Water-Related Technologies for Sustainable

Agriculture in U.S. Arid/Semiarid Lands

October 1983

NTIS order #PB84-172667
Library of Congress Catalog Card Number 83-600595

For sale by the Superintendent of Documents,

U.S. Government Printing Office, Washington, D.C. 20402
Foreword

Water is a major limiting factor in most areas where Western arid and semiarid

agriculture is currently practiced. Increasing water demands from nonagricultural

users plus growing problems of ground water depletion, salt buildup in agricultural

soils, and water-quality deterioration are causing heightened concern about the

sustainability of Western agriculture. A major part of this concern is focused on

whether the Federal agricultural system is prepared to meet the changing needs

of Western agriculture and whether technology can assist in providing the Nation

with Western agricultural production that is sustainable and profitable over the

long term.

This report assesses existing and emerging water-related technologies for their

ability to support long-term productivity of arid/semiarid agricultural plants and

animals in the context of institutional factors, water supply/use relationships, and

the characteristics of the renewable natural resource base on which agriculture

depends, The study was requested by the House Committee on Agriculture and

endorsed by the Senate Committee on Environment and Public Works, Subcommittee on Water Resources. The technologies examined by the study are generally

directed toward: 1) improving efficiency of water use, whether for rain-fed (dryland

and rangeland) systems or irrigation; 2) improving water management, storage,

and distribution for agriculture; and 3) augmenting existing supplies with additional water not previously available. The report also identifies a number of options for congressional action. A background paper containing examples of application of arid/semiarid agricultural technologies in foreign countries has been

published separately as part of this assessment.

The Office of Technology Assessment (OTA) greatly appreciates the contributions of the advisory panel, working groups and workshop participants assembled

for this study, the authors of the technical papers, and the many other advisors

and reviewers who assisted us, including farmers, ranchers, agricultural scientists

in government and universities, and experts in the private sector. Their guidance

and comments helped develop a comprehensive report. As with all OTA studies,

however, the content of the report is the sole responsibility of OTA.

.,.

I l l
—

Water-Related Technologies for Sustaining

U.S. Arid/Semiarid Lands Advisory Panel

James B. Kendrick, Jr., Chairman

Agriculture

Vice President, Agriculture and University Services, University of California, Berkeley

Alton A. Adams, Jr.

Adams & Associates

Virgin Islands

Thomas G. Bahr (resigned May 1982]*

Director

Water Resources Research Institute

New Mexico

Wilbert H. Blackburn

Professor

Department of Range Science

Texas A&M University

William T. Dishman

Farmer/Rancher

Idaho

Harold E. Dregne

Professor

Department of Plant and Soil Science

Texas Tech University, Lubbock

Chester E. Evans

(Retired, USDA Research Director)

Colorado

Larry J. Gordon**

Director

Albuquerque Environmental Health Department

New Mexico

Robert M. Hagan

Professor

Department of Land, Air, and Water Resources

University of California, Davis

David E. Herrick (Retired, USFS)

Western Agricultural Research Committee

Colorado

Helen Ingram

Professor

Department of Government

University of Arizona, Tucson

Cyrus McKell

Director of Research

Plant Resources Institute

Utah

Michael F. McNulty

Director

Tucson Active Management Area

Arizona Department of Water Resources

Milton E. Mekelburg

President

National Association of Soil Conservation Districts

Colorado

Clifford J. Murino

President

Desert Research Institute

Nevada

Alice Parker

Farmer/Rancher

Washington

Cynthia Reed

Rancher

South Dakota

Luis Torres

Program Director

American Friends Service Committee

New Mexico

Casey E. Westell, ]r.

Director of Industrial Ecology

Tenneco, Inc.

Texas

Norman K. Whittlesey

Professor

Department of Agricultural Economics

Washington State University, Pullman

—————

* Resigned to head office of Water Policy, U.S. Department of the Interior.

* * Until August 1982 Deputy Secretary of New Mexico Health and Environment Department

iv
OTA Water-Rekted Technologies for Sustainable

Agriculture in Arid/Semiarid Lands Project Staff

H. David Banta, Assistant Director, OTA

Health and Life Sciences Division

Walter E. Parham, Program Manager, Food and Renewable Resources Program

Barbara Lausche, Project Director

Phyllis Windle, Analyst

Rita Dallavalle, Research Analyst

Donald Alford, In-house Contractor

John Willems, Research Assistant

Kathryn White, Editor-Contractor

Administrative Staff

Phyllis Balan, Administrative Assistant

Nellie Hammond, Secretary Carolyn Swarm, Secretary

OTA Publishing Staff

John C. Holmes, Publishing Officer

John Bergling Kathie S. Boss Debra M. Datcher Joe Henson

Glenda Lawing Linda A. Leahy Cheryl J. Manning
—

Contents

Chapter Page

I. Summary and Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

II. Agricultural Production in the Western United States, . . . ., ..,,..,. 29

III. Water Supply and Use in the Western United States.. . . . . . . . . . . . . . 47

IV. Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

v . Institutions Affecting Western Agricultural Water Use... . . . . . . . . . . 109

VI, Technologies Affecting Precipitation and Runoff, . ..,,,..,. . . . . . . . 149

VII. Technologies Affecting Surface Water Storage and Delivery .., ,,,,, 181

VIII. Technologies Affecting Soil Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

IX. Technologies Affecting Water-Use Efficiency of Plants and Animals. 243

X. Technologies Affecting Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

XI. Selected Technologies Affecting Water and Land Management ,..,. 299

XII. Issues and Options for Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

Appendix Page

A. Features of the Arid and Semiarid Region . . . . . . . . . . . . . . . . . . . . . . . 351

B. Western Regional Water Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 355

c. Institutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385

D. Method of the Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

E. Acronyms and Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

F. Contractors, Work Groups, and Workshops. . . . . . . . . . . . . . . . . . . . . . . 398

Index .,....., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

vii
Summary

and Findings
Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . + ....!.... . . . . . . . . . . . . . . . ....+~~.o~s

Major Findings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..~~t+~-~

Western Agricultural Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...+.....

Water Supply and Use . . . . . . . . . . . . . . . . . . .. .. .. .. ... .s. .. ~..... . . . . . . . . . . . Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......+..

Institutions Affecting Western Agricultural Water Use . . . . . . . . . . . . . . . . . . . . . . .

Technologies: Making Optimal Use of the Hydrologic Cycle for

Arid/Semiarid Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Policy Issues and Options for Congress . . . . . . . . . . . . . . . . ....+......,.. . . . . . . . .

Treating Renewable Resources as Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sustaining Long-Term Productivity . ............................9.. . . . . . . . .

Involving Users in Decisionmaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

5

5

6

7

8

9

18

19

23

24

Table

Table No. Page

I. Federal Water-Data Collection Agencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

List of Figures

Figure No. Page

l. Arid and Semiarid Regions of the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Z. The Hydrologic Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3. Conflicts in Instream v. Offstream Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Chapter I

Summary and Findings

INTRODUCTION

As a Nation with bountiful resources, the

United States has rarely faced natural resource

limits. In the short history of this country, there

have always been more lands and more resources to develop and a philosophy that technology could supplement natural resources

when needed. Increasingly, however, some

Western States are experiencing resource limitations related to water use and distribution

that challenge the full capacity of existing social and technical institutions. The water problems to face this region and, therefore, the Nation in the 1980’s and 1990’s are likely to expand and intensify for agriculture. Stretching

resources to accommodate the West’s continuing growth while protecting existing patterns

of water demand may require levels of technical input no longer economically feasible. Concerted Federal, State, and local action will be

needed to help build a sustainable Western

agriculture that is profitable for the Western

farmer and rancher and that effectively addresses the complex and interrelated problems

surrounding the agricultural use of Western

water, A strong Federal role will remain fundamental to help bring about necessary

changes.

This study assesses the role of present and

emerging water-use technologies for sustaining the long-term agricultural productivity of

arid/semiarid agricultural plants and animals

and the renewable natural resource base on

which agriculture depends. The study considers increased demands on the resource, concerns about water quality, and the capacity of

existing institutions to respond effectively and

equitably to growing demands. Congressional

interest in this topic is important because the

arid/semiarid West (fig, 1) makes significant

contributions to this country’s agricultural production, providing unique benefits not easily

replaced by the other regions of the United

States. Its large expanses of land nurture cereal

grains and livestock. Its dry and disease-free

Figure 1 .—Arid and Semiarid Regions of

the United States

SOURCE: Carle Hedge (ed ), Aridity and Man (Washington D C American Assoelation for the Advancement of Science, publication No 74, 1963)

environment is especially suited to seed production and certain kinds of agricultural research. When irrigated, its soil, aided by low

humidity and many cloud-free days, produces

high-value specialty crops such as fruits, nuts,

and table vegetables. Much of the research and

development (R&D) of agricultural technology

that now benefits the entire United States originated in the West, where water application

could be carefully controlled.

3
4 ● Water-Related Technologies for Sustainable Agriculture in

———.—

This report is organized into two parts: background chapters on the state of the renewable

resource base and associated water institutions

(chs. II-V) and technology chapters containing

assessments of near- and long-term technology

potentials (chs. VI-XI). Technologies are organized in particular chapters according to the

principal components of the hydrologic cycle

[fig. 2) the technologies are meant to manipulate. Because water is a key factor dictating the

types of agriculture that can be sustained in the

water-short West, knowing the impacts of a

particular water-related technology throughout

the water system is critical. Benefits to one user

upstream could mean losses to another user

U.S. Arid and Semiarid Lands

————— .— -

downstream in reduced flow, reduced quality, or altered timing of flow. Alterations in surface water at one site could affect ground water

supplies at another hydrologically interconnected site. Moreover, technologies and land

uses may overlap at particular sites.

As used in this report, the term “renewable

natural resource base” includes soil, water, and

all the physical, chemical, and biological components of agricultural resource systems.

“Long-term,” as used in this report, means

more than one human lifespan (approximately

70 years) from the date of this report.

Figure 2.—The Hydrologic Cycle

Condensation

Transpiration

Water passes continuously through this cycle from evaporation from the oceans into the atmosphere through

precipitation onto the continents and eventual runoff into the oceans Human use of water may modify this cycle at virtualIy every point

SOURCE H Hengeveld and C DeVocht, Urban Ecology 6(1-4) 19, 1982
Ch. l—Summary and Findings ● 5

MAJOR

The following three major findings of this

assessment are the synthesis of individual

chapter findings which are discussed in more

detail below:

●

●

●

If agriculture in the Western United States

is to be conducted in a sustainable fashion,

a systems approach to decisionmaking regarding policies, plans, and programs affecting the agricultural resource base and

water-related technologies is a fundamental need, one that generally is lacking

throughout government.

The goal of sustaining long-term productivity of the agricultural resource base in

the western States is not being advanced

effectively by some existing Federal activities.

To ensure sustainable Western agriculture,

users must be involved in and must perceive equity and fairness in decisionmaking about water-related technologies and

resolution of conflicts over water use. Improved mechanisms are needed to expand

this involvement.

Western Agricultural Production

Products of Western agriculture constitute

a large share of the total income derived from

farming and ranching in the United States.

In 1980, cash receipts from marketing crops

and livestock and their products in the Western

States accounted for approximately $59.3 billion, or about 43 percent of the income derived

from farming in the United States. Some 30

percent of this sum came from export markets.

Unlike the Eastern United States, much of

the land in the West is federally owned:

Percen t

Federal Non-Federal Federal

(in millions of acres)

17 Western State s 368 790 32

31 Eastern States 3-1 705 5

The amount of public land varies from State

to State, from some 85 percent of Nevada to

about 1 percent of Kansas and Nebraska. These

public lands are used largely for livestock grazing and include major water-producing areas,

FINDINGS

The Federal ownership of these lands has generated Federal policies on use and management, policies that can substantially affect the

sustainability of Western agriculture.

Of the three types of agricultural production

(see box A) used in arid/semiarid regions,

rangeland and dryland agriculture are the most

extensive in area and rely on precipitation for

water supplies. Rain-fed agriculture makes

important contributions to the economy and

lifestyle of the West and is likely to increase

in importance. Present-day irrigation agriculture is especially significant because of the

large amounts of energy and supplemental water involved. It allows crop production in areas

where it might otherwise be impossible, and

farmers who irrigate generally have higher and

more stable yields and can risk growing crops

of higher value. However, irrigation agriculture

is the subject of particular controversy and concern at present. Some crops that are irrigated

are surplus. Moreover, competition for these

water resources is increasing from industries

and municipal users who can afford to pay

more for their water. Finally, depletion of

ground water resources threatens agricultural

producers and rural communities and diminishes the possibility of using this resource in

the future. These factors lead many analysts

Box A

Three broad types of agricultural production are common in arid/semiarid regions:

●

●

●

Rangeland agriculture—usually involves

grazing domestic livestock on grasses,

grasslike plants, forbs, and shrubs on

lands traditionally considered unsuitable

for cultivation.

Dryland farming—involves crop production through cultivation of the land and

relies on precipitation to supply plantwater needs.

Irrigation agriculture—involves crop production through land cultivation and uses

additional water to supplement normal

precipitation.
6 . water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

to believe that in the future Western irrigation

agriculture as practiced today will diminish

in productivity and profitability in some

areas.

Water Supply and Use

Available estimates of water supply and use

indicate that almost half of the Western

United States is experiencing water-supply

problems in relation to demand. Surface water shortages exist annually or seasonally in at

least some portion of each of the major water

resources regions of the Western States. In

almost all cases, these shortages are offset by

water reuse and ground water pumping. In

much of the Southwest and southern High

Plains, ground water is being withdrawn faster

than it is replaced (often called ground water

“mining”) in order to sustain developed levels

of use. Where water supply is not being consumed, competing nonconsumptive uses, such

as instream flow requirements for hydroelectric generation, waste assimilation, recreation,

Figure 3. —Conflicts in

.-

and habitat maintenance, increasingly create

scheduling conflicts for offstream uses (fig. 3).

Present trends and experience indicate that

every additional drop of water conserved, and

thus available, enables more growth and development, raising demand levels further. Effective water-use management will necessitate attention to demand as well as supply

aspects of water use.

The availability of water for agricultural use

varies by location and over time. Water supply depends on variations in components of the

hydrologic cycle—precipitation, evaporation,

transpiration, infiltration, and runoff, Because

these components interrelate, a change produced by technology in one component of the

cycle will inevitably affect other components.

The potential for a given technology to produce additional water or to conserve existing

supplies is difficult to evaluate and will remain so unless the quantities of water involved in the hydrologic cycle can be defined

more accurately. Various responsibilities for

Instream v. Off stream Use
the collection, synthesis, and dissemination of

hydrologic information are delegated among

a number of Federal and State agencies (table

1), resulting in a variety of data bases and data

interpretations that are often not compatible.

Important gaps in data exist, and few regional syntheses of data have been made. Shortterm climatic fluctuations affecting water supply can be accommodated in management and

planning processes through statistical analysis

of past trends; there is no reliable method for

predicting long-term fluctuations.

The most important source of renewable

surface water supplies in the Western United

States is the mountain snowpack. When the

snowpack melts in the spring and summer, it

supplies an estimated 70 to 100 percent (depending on location) of the total annual surface runoff for all river basins except the TexasGulf region. Relatively little research attention

has been given to the snowpack. Technologies

such as weather modification and the forecasting of streamflow to improve reservoir management would benefit considerably from increased understanding of the snowpack’s dominant role in renewing surface water supplies.

Ch. l—Summary and Findings ● 7

— —

Water Quality

Water quality is determined both by the nature of a pollutant and by the concentration of

that pollutant in water. The kinds and amounts

of impurities in water depend on a number of

environmental factors, such as the source of

the water, the physiographic characteristics

through which the water moves, and the effects

of human activity on water. The types of water

pollution can be categorized as follows:

1.

2.

3.

4.

5.

6.

7.

8.

municipal sewage and other oxygen-demanding wastes,

infectious agents,

synthetic organic chemicals,

mineral substances and inorganic chemicals,

sediments,

plant nutrients,

radioactive substances, and

heat.

Since the volume of water in the Western

United States is lower than that in the more

water-abundant Eastern part of the country,

any given water use in the West has a greater

Table 1 .—Federal Water-Data Collection Agenciesa

In-house data programs

Surface water .

Ground water. . . . . . . .

Water quality . . . . . ... . . . .

Water use. . . . . . . . . . . . . . . . .

Environmental impact . . .

Ecology . . . . . . . . . . . . . . . . .

Management effects . . . . . . . .

Basin studies . . . . . . . . . . . . . .

Real-time sensing . . . . . . . . . . .

Remote sensing . . . . . . . . . . . .

Data sensing . . . . . . . . . . . . . . .

Instream use . . . . . . . . . . . . .

Water rights . . . . . . . . . . . . . . . .

Floods . . . . . . . . . . . . . . . . . . . .

Energy . . . . . . . . . . . . . . . . . . . .

Nuclear. . . . . . . . . . . . . . . . . . .

Precipitation quality . . . . . . .

Government agencies Independent agencies

USDA

x

x

x

x

x

x

x

x

x

x

x

x

x—

—

—

—

DOC DOD

x x

-

— x

x x

x x — x — x — x — —

x x

x x — x — —

— —

x – — —

— —

— —

DOE

x

x

x

x

x

x

x

—

x

—

x

x—

DOI

x

x

x

x

x

x

x

x—

—

x

x

x

x

x

x

x

DOT

x

x

x—

x

x

x

x

x

x—

—

x—

—

—

EPA

x

x

x—

x

x

x

x

x

x

x—

—

—

x

x

x

IBWC

x

x

x—

—

—

—

—

—

—

—

—

—

—

—

—

—

NRC TVA —

— x — x — x — —

— x — x — x — x — x — x — x — —

— —

— x

x —

x – — x

KEY USDA—U S Department of Agriculture, DOC—Department of Commerce, DOD—Department of Defense, DOE—Department of Energy DOI—Department of the

Inter! or, DOT— Department of Transportation, Independent agencies EPA— Environmental Protection Agency, IBWC— International Boundary & Water Commission

NRC—Nuclear Regulatory Commission, TVA–Tennessee Valley Authority.

aFor the 1981.82 fiscal year 26 Federal agencies, representing six departments and four Indepen d

ent agencies colIected ‘water resource data

SOURCE U S Department of the Interior Geological Survey Off Ice of Water Data Collect Ion, Plans for Water Data Acquisition by Federal Agencies Through F/sea/

Year 1983 (Reston Va 1982) p 7
8 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

potential for causing water-quality degradation. The limited supply of Western water requires that each unit of water be more fully

used, resulting in patterns of reuse in which

each unit of water is used consecutively as it

moves downstream. Thus, water may be removed from a river and partially consumed for

irrigation; the return flow may be stored in a

reservoir and subsequently reused to generate

hydroelectric energy; and the remainder may

be withdrawn by a municipality for human

consumption. The return flows from each of

these uses often have increasing levels of pollution that, left untreated, can threaten uses

downstream, including agricultural uses.

Most water-quality problems appear to be

site-specific. The data base describing the

quality of water in the Western United States

is incomplete, however, and few integrated

analyses of water contamination as it affects

water reuse, environmental characteristics,

or public health have been performed.

The term “water quality” in agriculture

refers primarily to the quality of water used for

farm and ranch water supply, livestock watering, and irrigation. In evaluating the relationship between water quality and agriculture,

two aspects must be considered:

1. the effect of agricultural uses on the quality

of water for other uses, and

2. the effect of water quality on various agricultural uses.

The highest quality water required in agriculture is for domestic farm and ranch consumption. Much of the water used in this way

is well water, which in many areas is not routinely monitored for quality nor subjected to

any routine treatment prior to use. The quality of this water source is particularly susceptible to degradation because of the many potential sources of contamination in the farm and

ranch environments.

The quality of water used in irrigation is also

very important, When water applied in irrigation is lost to evapotranspiration during plant

growth, salts contained in that water are left

behind in the soil. Continued reuse of streamflows for irrigation without prior treatment

has become a necessity in many of the watersport areas of the Western United States. This

reuse can result in the gradual buildup of

salts and agricultural chemicals in the soil

and in water that is ultimately detrimental

to long-term agricultural productivity.

Agricultural water pollution can be reduced

by using improved management practices and

methods that result in fewer contaminants being released into the water supply, However,

present monitoring and control measures may

not be sufficient to prevent deterioration of

water quality caused by Western water use for

either agricultural or nonagricultural activities—e. g., municipal and industrial activities.

Institutions Affecting Western

Agricultural Water Use

Distribution of water in the Western United

States among uses and users responds to two

major institutional forces—the legal system and

the market system, The legal system defines

rights and responsibilities regarding the use of

water; the market system allows water to be

bought and sold, and thus transferred between

uses and users. The Western agricultural water user is, at best, moderately uncertain

about water use and the adoption of technology affecting water use because it is unclear

how legal and economic institutions might

change as demands for water increase.

The Western State water institutions developed in response to the surrounding conditions

of aridity and the initial character of Federal

ownership of the water and land. Their focus

was on allocating water-use rights to individuals as property rights. States deferred to Federal agencies for large-scale water-resources

planning and development because of the Federal Government’s financial and technical capabilities and its broad geographic jurisdiction

that facilitated interstate river basin development,

At the time Western law doctrines (Federal,

State, and interstate) were developed, the level

of definition given to water rights and duties
Ch. l—Summary and Findings ● 9

.

was adequate to address early development

needs, water law divided the resource into water-supply categories, the major categories at

the State level being surface water and ground

water. I n recent years, water-quality programs

have been developed with distinct bureaucracies and regulatory responsibilities separate

from those programs related to water supplies.

This treatment of water has caused conflicts

and confusion among users within and between States and has made water planning and

management problems more severe. As wateruse demands increase and values change,

more precise definition of such concepts of

beneficial use will be required to allow the

user greater assurance of return on investments in water “saved.”

Growing demands are creating conflicts

among agricultural, energy, industrial, municipal, Federal reserved water-right holders,

environmental, and other uses and values

and suggest that water in the West will become more expensive. Until now, Federal

sponsorship of many development activities

provided water at well below its “cost” or

‘‘value’ relative to much non-Federal water.

This sponsorship has slowed the development

of Western water markets and has shaped the

character and patterns of agricultural water

use in the Western United States. However, as

demands for water for nearly all purposes increase and as the scarcity of water is recognized, pressures will mount to shift water to

new uses and users. The rules of economic efficiency will support arguments that the development of water markets may be desirable.

Making such changes, however, must be

viewed in a context broader than the primary

or first use of the water. whether the water is

used for irrigation, navigation, recreation, or

hydropower as the primary use, that water also

generates secondary and tertiary incomes to

local economics. Transferring substantial

amounts of water to a new use will have a

profound effect on the people and on the supporting resources that are left behind.

In the past two decades,

to take a more active role

growing conflicts of water

25-160 0 - 2 : QL 3

States have begun

in resolving these

use and the associated social effects of the choices being made,

However, direct Federal involvement to address Federal water issues, topics of broad

geographical jurisdiction, international impacts, and equity concerns and to support and

assist States’ efforts will be necessary to ensure the sustainability of Western agriculture.

Technologies: Making Optimal Use

of the Hydrologic Cycle for

Arid/Semiarid Agriculture

Evidence suggests that some new and

emerging technologies have potential for sustaining the long-term productivity of Western

agriculture. These technologies are wideranging, and their effective application requires an understanding of their interrelated

impacts on the agricultural resource base. Such

technologies involve several natural and social

science disciplines, including hydrology (understanding water-related impacts), plant and

animal science (adapting plants and animals

to resist environmental stress), engineering

(improved irrigation-system management),

agronomy (cultivation practices and planting

techniques), and interdisciplinary sciences for

integrated agricultural land and water management (multiple-use of rangeland and cropland,

flexible cropping).

Water-related technologies for arid/semiarid

agriculture are general1y directed toward:

1.

2.

3.

4.

improving efficiency of use (and thus minimizing “waste” in such practices as irrigation),

augmenting existing supplies with additional water not previously available for

agricultural purposes,

preserving water quality, and

improving supply and distribution,

Technologies Affecting

Precipitation and Runoff

The renewable water resources of the West

originate as precipitation from air masses moving across the region. Surface runoff represents

that fraction of this precipitation not consumed

by evapotranspiration or infiltrated into the soil
10 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— -———

and ground water. Three major classes of technology have evolved around modifying or

anticipating the surface runoff fraction of the

original precipitation: weather modification,

watershed management, and water-supply forecasting. Each of these technologies has some

potential on at least a local, site-specific basis.

Evidence does not yet exist, however, to demonstrate that these are generally accepted operational technologies for sustainable agriculture,

Evaluation of any technology designed to

modify or forecast precipitation and/or runoff

from hydrologic environments in the region

would benefit from a more integrated approach to the study of the hydrologic regimes

of the Western United States than that which

now exists. Moreover, hydrologic research activities and priorities should reflect the fact that

most of the annual surface runoff and ground

water recharge in the West comes from the

mountain snowpack,

WEATHER MODIFICATION

Weather-modification technologies are designed to increase the amount of precipitation

over that which occurs naturally. This is done

by injecting artificial nucleating agents, such

as silver iodide, into suitable air masses. The

two weather-modification technologies that

have received the most attention are those involving: 1) winter storms that cross the major

mountain ranges of the Western United States,

producing the snowpack of the mountain watersheds; and 2) the summer cumulus clouds

that produce both rain and hail, often in large

amounts over limited areas. Of the two, precipitation augmentation from winter storm

systems by “cloud seeding” appears to show

the most promise. This technology has been

developed within a solid scientific framework

creating a body of knowledge that should facilitate future advances.

WATERSHED MANAGEMENT

Two major classes of watersheds occur in the

Western United States: 1) highland watersheds,

located in the major mountain ranges and consisting of the unlimbered “alpine” zone (above

the timberline) and the timbered “montane”

zone; and 2) lowland watersheds consisting of

grass- or brush-covered valleys and plains. Watershed-management technologies are designed

to increase surface runoff by vegetation removal or replacement or by other surface modifications,

No proven technologies exist to increase

water yield from the alpine zone. This area

may be the most efficient and productive

source of water in the Western United States,

and a passive, conservative management approach may be the most beneficial and effective management technology at present for

downstream users.

In certain situations in the montane zone,

vegetation management through timber harvesting may produce local increases in water

yield. It may be difficult, however, to detect

increased yields at points downstream where

arid/semiarid agriculture is practiced because

such increases, when combined with the entire volume of watershed runoff may not be

discernible using existing stream-gage technologies. Moreover, the ability to predict results of application on an unstudied watershed

is difficult because of the range of hydrologic

environments in the mountains of the West relative to that represented by existing experimental results. At some sites the effects of timber

harvest on soil erosion, other components of

the hydrologic cycle, or existing wilderness

values may negate potential beneficial effects

for downstream arid/semiarid agriculture,

Results of attempts to produce additional surface runoff from lowland watersheds have

been varied because of the natural hydrologic

variability of the lowland watersheds and the

range of purpose of the technologies. Because

practices are very site-specific, they have more

local than regional significance, In most cases

where the dominant vegetation consists of

shrubs and grasses, management should emphasize forage production and erosion prevention rather than surface runoff production.

Where surface runoff is collected and used for

cultivated crops and animal watering (runoff

agriculture), water-management practices can

provide an important local water supply.
.

Ch. I—Summary and Findings ● 1 1

..— —.—

STREAMFLOW FORECASTING

Water-supply forecasting is one of the most

important technologies related to precipitation and runoff in the Western United States

for long-term sustainable agriculture. Improvements in the accuracy of these technologies will entail advances in understanding the

impacts of weather modification and watershed management on the hydrologic environment. Improved water-supply forecasting

could provide the link between the resource

and the water user or planner because it

directly relates to the timing and volume of

water available to downstream or lowland

agriculture.

A wide range of forecast models exists, from

very sophisticated computer simulation technology to simpler statistical correlation models.

Research has indicated that no single forecast

model may be sufficient for all the hydrometeorological environments in the West. Research

also suggests that progress in accurately forecasting streamflow for certain regions in the

Western United States would reap considerable economic benefits for agriculture.

Technologies Affecting Surface

Water Storage and Delivery

Natural streamflow and precipitation seldom

meet agricultural demands for water in the

western States. Three approaches make more

surface water available when demand exceeds

supply:

1. increasing the total amount of

storage,

2. augmenting supplies with addit

ter, and

water in

ional wa3. stretching existing water supplies by conservation.

Currently, opportunities to develop large

sources of previously unavailable surface

water or to augment existing supplies are feasible technologically but are limited by economic, environmental, legal, and social considerations. They are unlikely to add significant amounts of water to irrigation supplies in

the future, Technologies that reduce water

losses [i.e., conserve water) in storage and delivery systems can be applied relatively easily

but tend to be expensive. In addition, their effects on the entire hydrologic cycle are often

difficult to measure and their application, at

times, can have unexpected, negative effects

on riparian (areas of shrubs, trees, and grasses

generally along streambanks) and wetland

wildlife habitats.

TECHNOLOGIES THAT STORE

AND AUGMENT WATER SUPPLIES

Technologies that increase the amount of

water in storage include storage facilities,

desalination processes, and interbasin transfers

of water.

Storage Facilities.—The extensive and complex system of large and small reservoirs in the

Western States represents about 79 percent of

storage capacity in the Nation. These storage

areas include a few reservoirs that contribute

much to the total storage capacity, a sizable

number of medium-sized reservoirs, and an

even larger number of farm and ranch ponds.

Storage facilities permit more convenient and

efficient use of available water supplies by

downstream agricultural users. Construction

technologies for reservoirs are well developed,

and technologies to manage reservoirs are advancing rapidly.

The Federal Government has a sizable investment (at least $26 billion) in completed water

resource projects and owns some 2,000 dams,

ranging in size from small reservoirs to large,

multipurpose projects. While the benefits to irrigators and other users have been sizable, the

costs have also been substantial.

Barriers to new, large-scale developments are

not technological; they are physical, economic,

and environmental. Because of these constraints, many experts expect that the Federal

role in building and operating new, largescale water-storage facilities will diminish

markedly in the future. New storage facilities

are likely to be smaller, and their construction

may depend increasingly on private and nonFederal public investment, Innovative costsharing arrangements could be encouraged between private and public developers and

among local, State, and Federal governments.
12 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—. . —

Desalination.— Desalination (removal of dissolved salts from brackish water, seawater, or

salt-degraded water) is a technology that can

supplement freshwater supplies. Desalination

can be accomplished by many methods and has

proven to be reliable for small amounts of

water. High costs are the major current limitation to use of desalination; further development is needed before the process can produce low-cost freshwater. Brine disposal is

also a problem. These considerations now limit

production of desalted water to municipalities

and industries and exclude most agricultural

uses.

Interbasin Transfers.—In the Western

United States, regional transfers of water from

one river basin to another—e. g., the Colorado-Big Thompson project—have been in operation for many years. Current attention focuses

on proposals to transfer water from areas of

supposed surplus (e.g., Alaska and the Missouri

River) to Western stream systems for irrigation

use. Such transfers will present considerable

problems for the foreseeable future. First, the

cost of irrigation water from an interbasin

transfer would probably be prohibitively expensive. Second, such transfers will present

complicated environmental, political, legal,

and institutional problems. Most important,

however, surplus water may not be available

for transfer since many areas are realizing

the present and future values of their water

onsite.

TECHNOLOGIES THAT CONSERVE

EXISTING WATER SUPPLIES

Technologies that conserve existing water

supplies have promise for meeting short-term

needs for irrigation water. These practices include flexible delivery systems for irrigation

water, seepage and evaporation control, and

vegetation management.

Flexible Delivery Systems for Irrigation

Water.—Timely delivery of surface water to irrigation users is a crucial element of effective

water management. In most arid/semiarid regions, delivery systems are based on supply

rather than demand because the water supply

is limited. Delivery schedules are prepared in

advance and are fixed for a preset time and

length. Adjustment in timing, duration, or

quantity of water application is limited. This

system favors water distribution over crop

needs.

A variety of technologies for improving

water delivery flexibility is being examined.

While the agronomic benefits of new waterdelivery technologies are likely to be substantial, existing irrigation facilities and practices

may require extensive modifications before

these benefits can be realized.

Seepage Control.–Seepage occurs through

the sides and bottoms of reservoirs and canals.

Its extent depends largely on geology, soils, and

topography. Water “losses” caused by seepage

can be large enough in some areas to prevent

reservoirs from filling; however, estimates of

the problem’s magnitude are difficult to make

and vary widely.

Seepage control can “save” water on a local

basis, and its effects can vary widely in different locations. For example, water lost through

seepage is not lost to the hydrologic cycle and

is generally available for downstream users, for

ground water recharge, and for plants and animals in wetlands and streams.

Although technologies to reduce seepage

are available (e.g., soil sealants and methods

that compact the earth), control is costly, a

primary limitation to use. As the relationship

between wildlife populations and standing

water from inefficient irrigation is explored

more fully, other limitations to use may be

identified.

Evaporation Control.—In arid/semiarid

lands, evaporation is high. In some regions, reservoir evaporation may reach about 40 percent

of usable storage. In small reservoirs, stock

tanks, and farm ponds, more water may be lost

than is used productively. Since conserving

collected water is one of the most economical

methods of maintaining an adequate water supply, considerable research has been devoted to

developing effective evaporation-control technologies. These technologies increase water

supplies, in effect, by increasing reservoir
capacity without new construction. They alter

the processes that contribute to evaporation by:

● lessening the amount of energy that

reaches the water surface to drive evaporation, and

● altering the ease with which vaporized water moves into the air.

Four methods of controlling evaporation

have received attention: 1) surface area reduction, 2) reflective coatings, 3) surface films, and

4) mechanical covers. Results from use of

evaporation-control technologies have been

variable and often disappointing. Reflective

coatings and surface film are unstable and ineffective if the water surface is not still. Small

reservoirs arranged in clusters and of varying

depths (frequently called “compartmented”)

experience substantially reduced evaporation

when volumes are managed to minimize the

exposed surface area. Mechanical covers show

high potential for use on small reservoirs, stock

tanks, and ponds.

Vegetation Management In and Near Surface Water.–Riparian zones constitute a small

fraction of Western lands. They are significant

to agriculture, however, and provide high-quality forage for livestock and are important in

maintaining water quality. Many water experts

believe that water “saved” by removing riparian vegetation remains in ground or surface

waters for direct human use. However, recent

research indicates that plant removal from riparian zones does not necessarily make more

water available for other immediate uses.

Consequently, less emphasis has been placed

on vegetation eradication. Other technologies

to manage riparian vegetation (e. g., chemical

methods to slow plant-water use) are limited

by high costs, unknown long-term effects on

wildlife, and difficulty in application.

Aquatic plants present a special problem for

irrigators because they interfere with water

movement, disrupt control devices, cause leaks

in canal linings, and lose water to evaporation

at rates greater than would occur from openwater surfaces, As many as 85,000 miles of U.S.

canals could be affected, and some water managers believe the problem is becoming more seCh. I—Summary and Findings ● 1 3

— —

vere, These problems have a large economic

impact,

Perhaps the most effective and least costly

approach to aquatic-plant management is prevention. But where aquatic weeds are present,

mechanical, biological, and chemical methods

of control are available, Of these, the chemical

methods are faster and easier; however, they

involve problems of water pollution, Mechanical methods are expensive, time-consuming,

and laborious, but are used by many water

managers, using biological methods—insects,

fish, and plants—is rare but generally effective,

economical, and minimally detrimental to the

environment,

Technologies Affecting Soil Water

Many opportunities for improving soilwater conditions exist, both where precipitation is used to supply crop- and foragewater needs (rangeland and dryland agriculture) and where additional water is supplied

to fulfill crop-water requirements (irrigation).

Technologies that conserve precipitation include practices that shape the soil surface,

manage the soil cover, and change the physical

or chemical properties of soil. Technologies

that supplement soil-water supplies include

drip irrigation, surface irrigation, sprinkler irrigation, and subsurface irrigation. Effective

use of precipitation and irrigation water often

requires the use of more than one technology

and skillful management of plants, water,

and soil.

The extent of soil-water increase that can

be expected with the adoption of a particular

technology or set of technologies is difficult

to quantify, given the wide variability y in site

conditions across the arid and semiarid region. Where water-conserving technologies are

used on irrigated land, data that assess the effects of adoption on total water supplies are

lacking. Similarly, information on economic

and social consequences of technology adoption is generally not available.

Some water-conserving practices have been

adopted by producers, but numerous barriers

remain to their widespread application. First,
14 ● Water-Related Technologies for Sustainable Agriculture

many of these technologies are effective only

under certain soil and/or climatic conditions.

Where site conditions are not appropriate, application can yield little or no improvement in

soil-water conditions. Second, some practices

require large economic investments for equipment, fuel, and labor; application costs may

outweigh their benefits in terms of higher farm

or ranch profits. Third, the use of some technologies is hindered by Federal and State institutions. For example, mechanical land treatments on public rangelands by individuals are

often prohibited; water saved by irrigators is

often not allowed for their reuse. Finally, some

practices are difficult to incorporate into existing farm and ranch operations and in some

cases require new equipment or skills.

Soil salinization of irrigated lands and

other effects of irrigation on natural resources (e.g., ground water depletion) lead

many experts to believe that present irrigation agriculture is not sustainable and that

existing practices will not make the contributions to agricultural growth that they have in

the past. If a shift to limited irrigation or

dryland or rangeland agriculture does occur,

Western agriculture will face a period of economic and social readjustment which will be

facilitated by development of a wide range of

new opportunities for production.

Technologies Affecting Water-Use

Efficiency of Plants and Animals

Agricultural production is handicapped on

almost 35 percent of U.S. soils by either

drought or salts, and much of this acreage is

in the West, In the past, these lands were often

ignored in the search for high-yielding crops

that were adapted to more favorable conditions. The methods used to “improve” these

lands—e.g., irrigation and drainage—are becoming less available and more expensive.

Therefore, technologies that improve the efficiency with which plants and animals use

water, yet do not entail extensive additions

of extra water, are likely to make large areas

more productive. These technologies include

new and traditional methods of improving existing organisms as well as the use of plants

in U.S. Arid and Semiarid Lands

— —

and animals that have not been widely used in

the United States previously or that are newly

domesticated.

In arid and semiarid lands, the efficiency

with which organisms use water has important implications for sustaining all types of

agriculture, influencing the growth, distribution, and survival of plants and animals.

Plants have evolved a number of different ways

of coping with water shortages; no single factor completely controls the way plants respond.

Plants may almost totally escape drought by

germinating, growing, and reproducing before

water becomes limited or only after a heavy

rainfall, They may resist drought with special

anatomical and physiological mechanisms to

take up, store, and retain water. Or they may

“tolerate” drought with mechanisms to limit

the destructiveness of internal water deficits.

The complex interaction of factors involved

with these responses has slowed the development of drought-resistant agricultural plants.

Animals exhibit a similar range of adaptations to limited water supplies. Some may

never drink water, obtaining moisture instead

from their diet and excreting little water. Since

the total amount of water used by animals is

small, there has been little effort to use or breed

animals that use less water. Instead, efforts

have been concentrated on ways to increase

the efficiency with which animals convert

plant biomass into their own.

IMPROVING PLANTS AND

ANIMALS WITH BIOTECHNOLOGY

Biotechnologies include intensive new methods of introducing genetic variation into bacteria, plants, and animals and reproducing the

results, Specific applications of biotechnology to the problems of water use in arid and

semiarid lands are underway and are likely

to increase substantially in the next 10 to 15

years.

Tissue culture of rangeland, dryland, and

irrigated crops is in commercial use and analogous methods are used in animal breeding.

Protoplasm fusion and recombinant DNA technologies are promising, but they face a poten-
—.. .

—

Ch. l—Summary and Findings ● 1 5

—. .— . —————

tially long period of basic research before being

widely applicable.

Institutional constraints to biotechnology use

exist in addition to the technical ones. There

is concern that reliance on laboratory practices

might narrow the genetic diversity of present

crops to an undesirable degree. However, concerns regarding the release of novel, potentially

dangerous, organisms have diminished. These

technologies have already had important effects on agricultural research and have led to

at least a short-term shortage of trained personnel. The fear exists that public sector agricultural research, handicapped by low funding

and the inability to attract scientists, may not

keep pace with private efforts and that there

may be little progress in the application of new

biological technology to problems of social importance with little foreseeable profit. While

much former skepticism has been allayed regarding the potential of biotechnology, such

capital-intensive enterprises use relatively

sizable amounts of public research money at

a time when research funds are increasingly

limited. Some concern exists that less glamorous technologies that also have significant

potential—e.g., new approaches to classical

plant breeding—will be overlooked.

INNOVATIONS IN CLASSICAL

PLANT AND ANIMAL BREEDING

Traditional methods of improving plants

and animals will remain important. These

techniques have accounted for yield increases

of as much as 1 to 3 percent per acre per year

for major annual crops. Range-plant breeding

has been revitalized by the need for surfacemined land reclamation. Classical crop-plant

breeding is likely to undergo an important shift

in focus, however, as breeding for water stress

becomes more important.

Identification of the character to be modified

is the single most important step in plant

breeding. It dictates both breeding and evaluation methodology. In many cases the fundamental mechanisms of adaptation to water

stress are not known. Where critical features

can be identified for breeding, they are often

not based on more than a few genes, unlike the

disease- and insect-resistant traits used successfully in past breeding programs. Thus,

direct plant breeding for drought resistance

awaits development of improved laboratory

technology, Meanwhile, genetic markers can

be used to correlate drought resistance with

more readily measured features.

With adoption of the 1970 Plant Variety Protection Act and its 1980 amendments, institutional constraints to the development of new

plant varieties decreased. Private investment

increased, and larger numbers of new crop varieties were released, Concerns remain, however. First, the trend toward fewer, larger seed

companies may have unanticipated effects on

germplasm availability. Second, the ownership

of seed companies by agricultural chemical

firms may foster breeding programs that

increasingly rely on agricultural chemicals.

Production of meat, fibers, and other products by ruminants is an important and appropriate use of unique Western resources. Breeding programs increase animal productivity,

sometimes by as much as 2 to 3 percent per

generation. Embryo storage and transfer, artificial insemination, and computerized herd

recordkeeping promise to accelerate increases

in animal productivity.

Some animal-breeding technology is available only to large ranches with high incomes.

Other methods promise to make important new

germplasm available to small ranchers for the

first time. Major economic changes are occurring in the livestock industry, some of which

are linked to the decreasing availability of inexpensive irrigated grains and forage. Shifts

in the distribution of feedlots, the demand for

red meat, and the relative importance of

sheep and goats may have substantial implications for innovations in animal breeding.

CHOOSIN6 ADAPTED PLANTS AND ANIMALS

Many major crops and livestock species are

not highly adapted to water stress, and their

lack of genetic diversity may make Western
16 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

agriculture overly susceptible to new pests or

harsh conditions. The broader use of native

organisms and the domestication of new

crops have potential for alleviating some of

the environmental problems caused by agriculture in the past and for tailoring it more

specifically to arid and semiarid lands.

Promising crop candidates include amaranth, tepary bean, guar, cowpea, jojoba,

guayule, saltbush, mesquite, buffalo gourd, and

milkweed, These are food and fiber crops, biomass energy plants, or sources of industrial

products. Their status varies widely. At least

one, grain amaranth, may be poised for major

entry into the agricultural market. Most others

face major institutional hurdles: lack of an

established market and infrastructure, disinterest from the established agricultural community, and incomplete research. Western agriculture may include “new” animals in the future,

but the use of rabbits, elk, buffalo, and other

species will probably not increase rapidly in

the short term.

Salt-tolerant organisms may extend the agricultural life of areas that are naturally saline

or that result from agricultural mismanagement. Adapting already salt-tolerant organisms

for agriculture may be faster than adding salt

tolerance to crops that now require freshwater.

Salt-tolerant crops of the future may include

algae, bacteria, and blue-green algae as well as

higher plants. *

Technologies Affecting Ground Water

Ground water use in the Western United

States almost tripled between 1950 and 1975,

and the ground water percentage of the

total water withdrawn in the region nearly

doubled. Much of this increase in ground

water use was made possible by technologies

that permit the withdrawal of ever-deeper

supplies at ever-faster rates, often in excess

of recharge. This ground water “mining” has

led to the noticeable depletion of ground water

in many of the agricultural areas dependent on

*Higher plants are those such as conifers and flowering plants,

which possess a well-developed conducting system. Plants such

as mosses, fungi, and algae are not part of this group.

——— —

it. Technologies to recharge these supplies artificially depend on a water surplus during at

least some portion of each year to use for recharge, Their effectiveness is also very sitespecific, dependent on suitable geologic characteristics and availability of land where

recharge ponds are to be used. In some situations, ground water overdraft may cause the

collapse (commonly referred to as “subsidence”) of underground, water-bearing formations. This process renders them incapable

of fully reabsorbing or transmitting recharge

waters and causes displacement of surface

structures. In many of the areas most affected

by ground water overdraft, the total available

renewable water resources are being completely consumed each year.

Water quality among the major ground-water

resource regions varies considerably with

ground-water recharge rates, rock chemistry,

and human waste-disposal practices. With the

exception of portions of the Pacific Northwest

and eastern Texas, the ground water of the

Western States is moderate to very hard with

high concentrations of calcium and magnesium salts. When water having high levels of

these or other salts is brought to the surface

and applied for irrigation, evaporation losses

lead to increases of soil salinity. Irrigation

return flows with high levels of dissolved materials and agricultural chemicals percolate

back into the ground water, producing a further deterioration of the existing quality.

Once a ground water aquifer becomes contaminated, there is relatively little that can

be done technologically and in a manner that

is economically feasible to remove or contain

the contaminant. A few technologies have

been investigated for dealing with groundwater contamination problems, but in general

these have been very expensive to implement

and have produced uncertain results, Technologies effective against ground water pollution

are those associated with surface and subsurface waste disposal designed to prevent contaminants from reaching the aquifer. Control

of toxic and noxious substances in surface

and subsurface waters will probably remain

the only feasible ground water pollutioncontrol technology in the foreseeable future.
—— —

While irrigated agriculture has consumed the

largest volume of ground water in recent decades in the Western United States, municipal

and industrial uses have also become increasingly important. Many Western cities are now

dependent on ground water and have a greater stake in its quantity and quality. While irrigated lands may be shifted to a lower value

use as water levels decline, cities cannot make

this transition so easily. The social costs of

declining water tables and increasing contamination of ground water resources of the

Western United States must be addressed as

both an agricultural and a broader social and

public health problem. Until more understanding has been gained, the most appropriate ground water technology may be prudent

and conservative management. It is probable

that, in the long term, ground water may

become much more valuable in some Western

areas than is indicated by its present value for

irrigated agriculture.

Selected Technologies Affecting

Land and Water Management

Much Western agricultural land suffers from

erosion, soil compaction, or other adverse

changes, and these lands require improved

management to restore their inherent productivity. In irrigated areas, improved water management may compensate for decreasing availability of affordable water.

Modern management technologies are developing rapidly and have potential for sustaining agriculture in arid and semiarid lands.

They represent a wide combination of individual practices involving animals, plants, cultivation equipment, irrigation systems, and computers. Few attributes are shared: some are

capital-intensive; others substitute labor for

capital. Some are highly specialized, while

others are diversified. At least two features are

common. The most promising technologies

are based on an understanding of the operation and limitations of the natural hydrologic

cycle, and they usually rely on significant

amounts of information about the natural

processes involved.

Ch. I—Summary and Findings ● 1 7

— —

WATER-MANAGEMENT TECHNOLOGIES

Water management includes flexible cropping, irrigation scheduling, water reuse, conjunctive use of surface and ground water, and

crop enclosures. Several of these rely on relatively sophisticated methods of assessing soil

and plant water requirements, Additional research is needed to validate the accuracy of

some techniques. More well-developed water-management technologies may not be

available to managers because of high costs,

a lack of trained personnel or suitable programs to transfer information to the producer, or the manager’s inability to implement recommendations. Federal policies may,

in some cases, impose an additional constraint

on technology adoption.

Reuse of municipal wastewater may represent a source of additional irrigation water and

a possible method to reduce water pollution.

Before this technology is implemented, however, questions must be resolved regarding its

long-term effects on renewable resources and

health. Legal, economic, and policy questions

about ownership of reused water, its market

value, and its allocation to uses besides agriculture must be answered.

Conjunctive use of surface and ground water

may be technically feasible, depending on local

geology and the extent to which ground water

is manageable over a wide range of depths. It

requires careful planning and the thorough understanding of local water resources.

Enclosures for plants and fish, especially

those using solar energy, have potential for

using unique Western resources, particularly

the high amount of incoming solar radiation

characteristic of the region. At present, they

are suitable only for high-value agricultural

products.

LAND-USE MANAGEMENT TECHNOLOGIES

With uncertain economic and resource conditions, such as increasing energy costs and

unknown water availability, production specialization may involve increased risks. Therefore, technologies that integrate different
18 . water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

——.———- — —— — . —

types of land use and different types of agricultural and nonagricultural products are

especially promising for stabilizing economic

risk. Land-use management technologies are

diverse and reflect a range of agricultural

philosophies. They include alternative agriculture, multiple land use on rangelands and farmlands, and animal mixtures on rangelands.

Alternative types of agriculture have largely unexplored potentials in arid and semiarid

regions. These new systems may include complex mixtures of crops in one field, perennial

grains or tree crops instead of annuals, or the

elimination of synthetic pesticides and fertilizers, Generally, they rely heavily on natural

biological processes.

Diversified farming and ranching have important benefits in areas where climate is unpredictable or the economy is unstable. Most

types of land are amenable to some type of diversified enterprise; however, markets for

products, restrictions on the use of public land,

and specialization of agricultural production

hinder adoption of these management systems.

Increasingly, rangelands are used for multiple

purposes. Some of these uses are not compatible with agriculture, and their effects on production and natural resources need to be considered.

The more complex management methods

have received little research attention. These

methods have potential for improving use of

arid- and semiarid-land resources and for increasing farm income. In the past, interested

private experimenters have often been isolated

from one another, and this has hindered wide

dissemination of knowledge about these practices.

COMPUTERS AND INFORMATION MANAGEMENT

Computers are having a major impact on

agricultural extension services and on individual farmers and ranchers. They assist in

recordkeeping and help prevent costly management errors. Their role is likely to increase

in the future, but questions remain regarding

fair access to computerized information and

the reluctance of many Western farmers and

ranchers to adopt computer technology.

POLICY ISSUES AND OPTIONS FOR CONGRESS

Agriculture

arid/semiarid

as it is known today in the

United States is being increasingly threatened by water-related problems.

Federal agricultural and water-related institutions are poorly prepared for the long-term

needs brought about by these problems.

Change is inevitable and in some areas is likely to be severe if current trends continue.

Whether change ultimately produces a sustainable Western agriculture that strengthens the

agricultural producer,

tion depends in part

chooses or declines to

years.

the region, and the Naon the role Congress

play in the coming few

Theoretically, future congressional action

might range from delegating all control over

water resources to States and regions to preempting State laws completely and nationalizing the water resource. Israel’s successful national water-management program is based on

this latter action, providing a national focus

and goal with respect to water. More likely, appropriate actions for Congress lay between

these extremes. For example, this Nation has

neither a comprehensive national water (surface and ground) policy nor a national agricultural policy. As limits are reached and longterm productivity is threatened in the West,

Congress may be asked to decide whether it

will, acting for the Nation, develop an effective national water policy or whether States

and regions will be left to fill the vacuum in

water-resources management and planning.

The actions chosen will depend on the level

of this Nation’s commitment to protecting the
Ch. I—Summary and Findings ● 1 9

—— —. .——

long-term productivity of its renewable resources.

However, Congress alone cannot act effectively in this complex and diffuse area. Federal,

State, and local governments are all involved

in the regulation of Western water, for agricultural and other uses, and thus affect use and

development of water-related technologies for

arid/semiarid agriculture. The broad types of

Federal tools available to influence use and

development of these technologies involve institutional action to develop an improved statement of goals and priorities for Western water

use and agriculture, provide incentives, penalize abuses, promote improved management,

equitably resolve conflicting claims and demands, and provide more and improved information.

In recent years, awareness has increased that

most of the West’s water-resource problems

transcend State boundaries and are extremely difficult in nature, involving a complex web

of physical, chemical, biological, economic,

legal, and sociopolitical issues. Often, they go

well-beyond the ability of a single agency, State,

university, or group of organizations to address

effectively. Western States have begun to take

impressive steps to increase their role in regional interaction and water-resources planning and management (see examples in app.

C). However, they cannot handle all the problems alone. The need for an active Federal

commitment to water-related matters of broad

public concern and wide geographical jurisdiction has become increasingly evident for sustainable Western agriculture.

The following policy issues and options have

been identified by OTA as those most critical

for congressional action over the next few

years. They are grouped in three major categories (treating renewable resources as systems, sustaining long-term productivity, and involving users in decisionmaking) to parallel the

three fundamental findings of this assessment.

They are not listed in any order of priority.

Treating Renewable

Resources as Systems

This major action area is divided into three

categories:

1. how Western scientists, water users, universities, and the public-at-large can play

an expanded role in decisionmaking about

water and Western agriculture;

2. how congressional decisionmaking can be

strengthened; and

3. how other Federal and State Government

agencies can improve specific programs.

Issue 1: The Need for an Interdisciplinary

Program of Basic and Applied

Research on Arid/Semiarid-Water

Resources

The Nation’s universities, water users, and

private sector have a variety of research programs on water resources and water-resource

management and could provide unique services in arid/semiarid-water resources research

and decisionmaking. At present, however,

links are often not made to broader national

or regional problems and there is a lack of a

national coherence and synthesis of university water-related research. Progress in Western

water-resources research, both basic and applied, could benefit substantially by the creation of a broad coordinating mechanism to focus and interrelate the multidisciplinary talents

of the academic community and water users

with the resources of the private sector. The

Nation’s universities are especially important

to tap at a time when Federal assistance to

coordinate water planning and research has effectively disappeared.

Option: Congress could establish a National

Center for Water Resources Research to provide a coherent and coordinated mechanism

for the Nation’s university research programs

in water resources and water-resource management for problem-solving and policymaking.
.20 ● Water-Related ——

Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— ——— ——

The mission of this center could include:

1.

2.

3.

4.

Undertaking an interdisciplinary program

of basic and applied research on water resources and water-resource management,

including strong programs in the natural

sciences, engineering, and social sciences,

such as resource economics and law as

they pertain to water-resources programs.

The center could further assist in the conduct of site-specific research being carried

out under State auspices.

Developing and providing advanced and

sophisticated research facilities on a scale

required to cope with the broad nature of

water-resources problems, and often not

affordable by single universities, to be used

by resident staff, innovative producers,

and university scientists.

Undertaking a program to develop and test

conventional and emerging technologies

for application to water-resources problems in United States arid/semiarid lands,

including problems of agriculture and its

sustainability in arid/semiarid lands, and

coordinating such efforts with existing

government research by USDA and State

agricultural experiment stations.

Serving as an objective, nonpartisan, and

continuing national source of information

for Congress when formulating public policy dealing with water resources, and as

a link to public agencies, water users, and

the private sector for application of research findings.

This center could serve as a base for marshaling university and private industry talents and

for augmenting, but not in any sense competing with, university work already underway.

Using the successful experience of the National

Center for Atmospheric Research (NCAR), an

institution created some 20 years ago by an act

of Congress, the center could be managed and

operated by a consortium of universities with

doctoral-level programs in water resources. An

essential aspect for effective operation is that

prime responsibility for program initiatives

reside with this consortium. This requirement

is in sharp contrast with “Government ownedcontractor operated” laboratories where program initiatives commonly reside in the sponsoring, mission-oriented Federal agency. This

contrasting approach for the center is important, since the university community is closest

to the research and its potentials. In light of

this knowledge, plans and priorities designed

by the consortium would take into account national, regional, and State needs.

Issue Z: The Need for Congress to Have

Reliable Ongoing Information

About the State of the Nation’s

Renewable Natural Resources

The assessment finds that existing data available for congressional decisionmaking is scattered throughout the Federal Government in

a variety of forms. These data were not collected with the intention that each piece would

be part of an integrated and self-consistent base

for Congress to use in making decisions affecting resource sustainability, Moreover, existing

data on components of the resource base on

which agriculture depends are seldom synthesized because the data may be in noncompatible forms and no single agency has had the ongoing responsibility to seek compatibility or

synthesis.

Congress needs improved information for

setting near- and long-term goals for sustainable use of Western water and agricultural

lands. This information should focus on congressional needs and emphasize systems analysis of the natural resources on which agriculture depends. Ongoing analysis and synthesis

of existing data bases could provide improved

information on the dynamics of the resource

system and how interactions (natural and

manipulated) among resource components affect the sustainability of Western agriculture,

Option 1: Congress could develop a bipartisan unit within the legislative branch with

the principle purpose to provide Congress

with ongoing quantitative evaluations of the

state of the renewable natural resource system as a consequence of near- and long-term

congressional policies. The unit’s program
.

Ch. l—Summary and Findings ● 2 1

———— .

should be interdisciplinary and multidisciplinary, with access to state-of-the-art computer

facilities to conduct comprehensive data analysis and synthesis from existing data sources

on specific topics requested by Congress. Such

a unit could identify data gaps important to

U.S. decisionmaking that affects the sustainability of the renewable resource base. It would

require independence and flexibility to obtain

and interpret data in a nonbiased fashion for

the entire Congress. Specific organizational

structure and legislative authority would have

to be developed to meet the unit’s defined

purposes.

The first step in considering this option

might be a workshop of interested and involved

congressional, executive, State, and local participants to examine existing problems, the history of similar attempts and experiments in

data synthesis, and possibilities for action. This

workshop might be combined with the formation of a joint committee of members from relevant House and Senate committees to plan

subsequent steps.

This option will require ongoing communication among the many branches of Government

to achieve an acceptable arrangement for the

new unit. Some individuals within Congress

and the executive agencies may question the

value of such a unit for a number of reasons.

In recent years, public concern has increased

over the growing size and cost of congressional

staffs. Others may claim that existing agencies

are competent and qualified to provide Congress with the resource systems analytical capacity.

Option 2: As an alternative to option 1, Congress could develop an executive branch unit

to provide ongoing quantitative evaluations

for congressional decisionmaking affecting

resource sustainability. On congressional request, this unit could coordinate, integrate, and

interpret existing information similar to that

noted for the legislative unit proposed in option 1, and report directly to Congress. Traditionally, Congress has turned to the executive

branch for answers to fundamental questions

involved with its policymaking, Existing executive agencies have personnel, equipment,

and many separate data bases; some career

staff have experience in aspects of water- or

agricultural-data collection and analyses, partial funding might be available for this option

through redirection of existing funds from

lower priority executive activities, as determined by Congress.

Possible disadvantages of this option relate

to the adequacy of existing agencies to incorporate this function and the nature of executive

branch programs in general. The capacity of

existing executive agencies for long-term and

multidisciplinary resource systems planning is

seriously lacking, The placement of this systems capacity in the executive branch poses

concerns about continuity. Programs and priorities in the executive branch change with administrations. A small new executive unit is

unlikely to be in a secure position to provide

objectivity, coherence, and continuity, essential requirements for effective long-term data

syntheses. In recent years Congress has found

it necessary to develop inhouse expertise to

supplement executive branch input in areas requiring focused analysis, integration of issues

or activities, and verification or clarification

of executive branch reports.

Issue 3: The Need to Integrate WaterRelated Agricultural Activities in

Government Agencies

Increased demands are being placed on the

arid/semiarid-agricultural resource base as

pressures grow from new and expanding water

uses. The complexity of the natural processes

in arid/semiarid agriculture requires an integrated approach to resource manipulation in

order to cope effectively with these increasing

demands and to ensure a sustainable agriculture, No longer can Western water-related agricultural problems be trusted to one-problem/

one-solution procedures that have been relied

on chiefly in the past by government institutions.

Federal agencies charged with implementing

congressional policies and programs need a

perspective that interrelates technological impacts as they affect various components and

ultimately the agricultural system and long-
22 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

.— —.. . — —-— —

term productivity of the region. The following

options are specific areas conducive to immediate congressional action, All four are compatible.

Option 1: Congress, through the hearing

process, could initiate discussions with

USDA for the purpose of designing and establishing a high-level office to integrate and

provide coherence to water-related and agricultural activities within the Department.

This office of resource coordination should be

placed at an appropriately high level—e,g., in

the Office of the Secretary of Agriculture—to

minimize confusion in organizational responsibilities and to ensure coordination and integration of activities among all specialized agencies of the Department. This office could have

responsibilities for analyzing programs of the

specialized agencies, for helping formulate a

systems perspective that integrates the agencies’ resource programs, for minimizing narrowness of focus and potentially conflicting activities, and for overseeing implementation of

integrated programs in research, technology

development, and production in long-range

sustainable arid/semiarid agriculture. An office

at the level of the Secretary could emphasize

the importance of agriculture’s natural resource base and make visible the role of the Department in protecting it. It could encourage

the Department to take advantage of the most

modern systems-analysis technology, technology that has not commonly been used in agriculture.

Option 2: Congress could instruct Federal

land-management agencies responsible for

Western areas to increase efforts in water

resources and water-resources management

pursuant to their existing multiple-use responsibilities for managing natural resources

on public lands. Existing multiple-use statutory guidelines prohibit optimization of single

measurable uses (e.g., timber and cows) at the

expense of less quantifiable uses (e. g., watershed and recreation), and they forbid practices

that impair long-term land productivity, This

option will entail a reorganization of agency

priorities such that more emphasis is placed

on long-term benefits from water management

and less emphasis is placed on short-term revenue-producing benefits from grazing and

timber production. This is an area of considerable importance for long-term Western

water-resources management and arid/semiarid agriculture because most Western surface

water-producing areas are on public lands.

Option 3: Congress could assist States to develop and integrate computerized data bases

for the wide range of hydrologic data now

scattered among State and local agencies and

private industry. Such information is not being entered into Federal data storage systems

but is increasingly needed for effective water-resources planning and management at the

regional, State, and local levels, Data bases

could be designed to ensure integration of

water quality and quantity data for systems

planning. Federal funds to States for waterresources planning and coordination could be

allocated for State participation in this data

system. The private sector could share data and

give advice on the best available technology for

data storage, retrieval, and processing.

Option 4: Congress could expand mandates

of Federal agencies responsible for waterproject development and maintenance to take

into account needs of instream flow, a subject that has had inadequate and, in recent

years, reduced attention at the Federal level.

Some minimum instream flow requirements

are essential for rivers for dilution, hydroelectric generation, and fish and wildlife habitat

protection. In many river systems of the West,

however, virtually the entire flow of the river

is committed already to various offstream uses.

In view of the geographic nature of river systems, an increased Federal role is needed to

help define and monitor instream flow requirements of Western rivers. The maintenance of

instream flows may make it possible to maintain acceptable water-quality levels in some

Western rivers without the need for greatly increased water-treatment facilities. An improved understanding of instream needs for

the multiple purposes of Western river systems

will also improve management information for

planning long-term requirements of the various

water users.
—

Ch. l—Summary and Findings . 23

— . —

This option may raise additional burdens as

well. Traditionally, the Federal Government

has deferred to the States on matters involving local water rights. Virtually the entire flow

of many Western river systems is committed

already to various local offstream uses. If instream flow requirements are to be met on

these rivers, some existing off stream uses

might have to be curtailed or discontinued.

Federal involvement will raise all the difficulties inherent in trying to coordinate and

respect these two governmental systems, the

longstanding States’ interests in local water

rights and the broader geographic and national

interests of the Federal Government.

Sustaining Long-Term Productivity

Issue 1: The Need for a Strong Federal

Role in Water Quality for

Sustainable Western Agriculture

Congressional action to maintain strong water-quality standards, support pollution controls, and strengthen water-quality research is

essential for protecting agriculture, the environment, and the public health of the arid/semiarid West. Because of the West’s low or sporadic water-volume flows, the region cannot

absorb the levels of industrial, municipal, and

agricultural pollution possible for more waterabundant regions. Without the maintenance of

a strong and committed Federal role, it is conceivable that agriculture in some areas may go

out of production because of water-quality degradation rather than loss of supplies.

Three options are particularly important, and

all are compatible for immediate congressional

action.

Option I: Congress could maintain a firm

commitment under the Clean Water Act to

strong water-quality standards that are applicable across the Nation in order to ensure that

economic burdens and benefits are evenly

shared among States and to avoid industrial

“shopping” for areas where water-quality

standards might be low. National waterquality standards must be stringent in order to

protect the range of present and future interests

in water, some of which require the highest

standards (e. g., for drinking-water purposes).

Existing requirements could be retained, and

any new or revised water-quality standards

could be made to enhance the quality rather

than allow degradation.

Option 2: Congress could refine national

nonpoint source policy under the Clean Water Act and particularly under section 208 of

that act, and accelerate implementation of

controls on water pollution from nonpoint

agricultural sources. Knowledge exists to

reduce water pollution from agricultural nonpoint (diffused) sources through the adoption

of improved management practices. Some of

these practices may involve costs that are difficult for economically disadvantaged farmers

and ranchers to absorb over the near term.

However, such costs may be far outweighed

by long-term benefits in reduced water-treatment costs and public health problems and

thus justify Government assistance with implementation. As part of this action, Congress

could strengthen Federal support to State and

local efforts to achieve nonpoint source pollution reduction. Because the water-short Western States face more concentrated contamination possibilities with any pollutant, progress

toward implementing control programs is essential, Increased Federal support could come

in a number of forms, including providing incentives, assisting economically depressed

farmers to adopt better practices, and offering

technical and financial assistance for training

farmers and ranchers to implement control

measures.

Option 3: Congress could increase research

and monitoring of short- and long-term agricultural and public health effects of Western

surface and ground water-quality deterioration. Little water-quality research has been

undertaken on a comprehensive areawide basis

or on related health and environmental impacts

of water-quality degradation, Existing standards may not adequately protect the public in

some areas, while others may be too stringent.

In view of the West’s low or sporadic water-volume flows, the prudent approach is to maintain high or more stringent standards for both

surface and ground waters and to support high
24 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

levels of water-quality research to ensure longterm protection of the public health and of the

environment on which agriculture depends.

Particular focus could be given to synthesis of

existing information, most of which is scattered and contaminant-specific, and to research on likely agricultural contaminants that

are detrimental to other uses and on contaminants from other uses that are detrimental to

agriculture. Such activities could provide valuable information for national and local policymaking to protect ground waters and surface waters from contamination.

Issue 2: Protecting and Maintaining the

Long-Term Productivity of

Rain-Fed Agricultural Resources

Protecting the renewable resource base for

productive rain-fed agriculture in the arid/

semiarid West is a growing national concern,

especially since irrigated production in some

areas is likely to decrease because of water

problems. Two areas, in particular, have received inadequate Federal attention in the past.

First, the problem of cultivating marginal or

unsuited lands (“plow-out”) has become particularly critical in the semiarid lands of the

Great Plains and in other States in the West

where the land is especially vulnerable to erosion. Some Federal agricultural programs encourage cultivation of fragile lands and thus

contribute to resource degradation. Second,

dryland and rangeland research and technology development have received scant Federal

support. This area is particularly important for

expanding the range and mix of opportunities

for productive Western agriculture on rain-fed

agricultural lands over the long term. The

following two options are important and compatible.

Option 1: Congress could withdraw those

Federal programs that induce conversion of

rangeland to uses not suited to that land and

thus cause resource degradation that ultimately limits long-term productivity. One

method of achieving this could be to require

that applicants for Federal agricultural assistance certify that their land is not new cropland

or, if so, to demonstrate that a conservation system approved by the local conservation district

is, or will be, in place for the land to be put

into production. The land-capability classes

could be used as a guide for determining what

lands are unsuited for cultivation and thus ineligible for Federal assistance, except with an

approved conservation plan.

Option 2: Congress could direct that USDA

increase its R&D focus on rain-fed agricultural systems—both dryland and rangeland.

Significant opportunities exist to develop and

expand dryland and rangeland research into

broader areas of focus than now exist. Increased support is needed if this Nation is to

have the range of alternatives necessary to ensure flexibility in meeting anticipated and unanticipated future needs for agricultural production in the West. As one means of implementing this option, Congress could hold hearings with USDA to examine that Department’s

existing field research stations. The purpose

would be to identify and convert appropriate

stations to facilities for testing and developing

technologies, based on an integrated resource

approach, to sustain or improve rain-fed agricultural productivity of these arid/semiarid

lands over the long term. The work could be

made readily available to producers through

special pilot projects and field-days and

through the conventional extension programs,

InvoIving Users in Decisionmaking

Issue 1: Achieving Equity in Western

Water Availability and

Distribution

Lasting settlement of conflicts over Western

water use must involve principles of equity and

fairness for current users, for those whose

rights have yet to be developed, for those whose

communities and lifestyles might be affected

by major water shifts, and for new users with

economic power who seek to buy water supplies, Already, perceptions are growing among

poorer farmers and American Indians that existing Western institutions responsible for

water distribution and development have not

treated them fairly. Without committed congressional action, conflict, distrust, and litiga-
Ch. I—Summary and Findings ● 25

.

Issue 2: Understanding the Impacts of

Water Prices on Adoption of

Technology
26 . water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— —— -. ——..—.

Issue 3: Improving the Effectiveness of

Water-Related Technologies for

Sustainable Agriculture

Development and successful application of

water-related technologies depend, in part, on

the ability of the researcher and user to adapt

them to local conditions. This is a result of the

complexity and spatial and temporal variability

of the natural resource system on which agriculture depends. In addition, the researcher’s

perspective about effectiveness may vary from

that of the user. The former r-nay be concerned

with technical efficiency, while the latter is interested in economic efficiency for farm or

ranch use. A gap appears to be growing between the researcher and user of water-related

technologies in Western agriculture in some

areas. Research for both onsite and offsite technologies commonly suffers from questions of

relevance and practicality for a particular agricultural site and user.

Option: Congress could direct the establishment of two user oversight groups specifically

focused on Western water and agriculture.

One user group could address onsite waterconserving technology potentials and needs

and provide advice principally to USDA. The

other user group could focus on offsite water

augmentation technologies for downstream

agriculture. This second group could advise

Federal agencies responsible for those waterrelated technologies (e. g., weather modification, watershed management, snowmelt forecasting) applied upstream or in highland areas

offsite from arid/semiarid agriculture but having potential water-related impacts for downstream or low-land agriculture. Each user

group could advise appropriate congressional

committees as well.

By making use of innovative producers and

by bringing the research to the farm or ranch,

this option could improve research/user interaction, an essential aspect of effective technology development and adoption now seriously lacking in many areas. User groups could

assist Congress to determine whether existing

programs are doing the job needed for sustainable agriculture from the Western users’

perspective.

Concerns about this option relate to the possible effectiveness of the user groups. At present, a National Agricultural Research and Extension Users Advisory Board (UAB) exists

pursuant to legislation in the Food and Agriculture Act of 1977, A recent OTA report* on

the food and agricultural research system

found this board’s effect on USDA research priorities to be unclear. Other concerns are that

researchers who interact with user groups

would be taking time that might be spent otherwise with laboratory or field work. Moreover,

the focus of particular users might be on shortterm economic solutions rather than longrange issues involved with the development of

technologies for sustainable agriculture.

Precautions in establishing these groups will

be required to ensure that they effectively

represent the range of users’ views, include

long-range interests, and have the capacity to

evaluate and scrutinize Federal agency research work. Congress could require that users

be nominated by representative agricultural organizations and have access, when necessary,

to scientific expertise independent of the

Federal agencies. Membership rotation could

ensure a flow of new ideas to minimize loss

of research time on new potentials.

.—

*An Assessment of the Unittxi States Food an(f Agricultural

Research S~stem, OTA-F-1 55, December 1981.
Production

Agricultura l

in the Western United States
Page

Characteristics of Arid/Semiarid Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Features of Western Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Western Agriculture in the National Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Types of Agriculture in the Arid and Semiarid Region . . . . . . . . . . . . . . . . . . . . . . . 34

Structure of Western Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Chapter II References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

List of Tables

Table No. Page

2. Agricultural Land in the Western States, by State, 1978 . . . . . . . . . . . . . . . . . . . . . 30

3. Ownership of Land in the 17 Western States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

4. Cash Receipts From Farm Marketing, 17 Western States, 1980 . . . . . . . . . . . . . . 31

5. Selected Major Crops Harvested in the 17 Western States, by Acreage, 1978... 33

6. Market Value of Major Agricultural Products Sold, 17 Western States, 1978 . . . 34

7. Agricultural Exports in the 17 Western States, by Value,

October-September, 1979-80 and 1980-81 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8. Agricultural Services: Number of Establishments, Gross Receipts and Payroll,

by State, 1978 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9. Nonirrigated and Irrigated Cropland, 17 Western States, 1977 . . . . . . . . . . . . . . . 38

10. Irrigated Acreage of Selected Crops, 17 Western States, 1978 . . . . . . . . . . . . . . . . 40

List of Figures

Figure No. Page

4. Arid and Semiarid Regions of the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5. Schematic of Western Agriculture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6. Irrigation Development in the Central and Southern Great Plains, 1944-74 . . . . . . 37

7. Vegetation Types in the Arid and Semiarid Regions of the United States . . . . . . . 37
Chapter II

Agricultural Production in the

western United States

Throughout the history of the United States,

agriculture has helped shape the Nation’s people, prosperity, and outlook. Self-sufficiency in

agriculture served to transform a rural, agrarian society into a largely urban, industrial one.

Internationally, American agriculture played

a vital part in supplying food to those in need

during periods of crises such as war, crop failure, and famine.

Today, agriculture continues to supply an

abundance of relatively low-cost food and fiber

to domestic consumers. Agricultural exports,

in recent years, have been especially valuable

to the domestic economy by creating a trade

surplus to offset, in part, the deficit in some

nonagricultural trade accounts. Agriculture

also provides a livelihood to workers directly

involved in agricultural production and in

related industries such as food processing,

farm equipment manufacture, and transportation of agricultural goods.

Arid and semiarid lands comprise about onethird of the contiguous United States and are

an integral part of the Nation’s productive

capacity. Particular qualities of the area make

it especially suited to certain types of agriculture. The climate, characterized by low humidity and many cloud-free days, is ideal for some

irrigated and nonirrigated crops such as wheat,

sorghum, cotton, potatoes, barley, and specialty crops such as fruits, nuts, grapes, and table

vegetables. In some areas where the growing

season is long, farmers can produce crops

throughout the year. Seed and nursery stock

production are also well-suited to the arid and

semiarid region because the area’s dry climate

discourages growth of plant pathogens.

The arid and semiarid region is well adapted

to animal production as well. Large acreages

of land not suitable for intensive cultivation

provide low-cost forage for animals that are

used for meat, hides, or wool.

In addition, Western agriculture extends the

diversity of agricultural production in the Nation and further ensures that domestic consumers have a reliable and varied food supply.

Moreover, it is an important component of

many local economies and contributes to the

perception of a Western lifestyle. Many production technologies originated in U.S. arid

and semiarid regions and were then transferred to more humid areas or to other countries.

Finally, in an age of increasing urbanization,

the wide expanse of open land, characteristic

of the region, offers visual amenities and numerous recreational opportunities and supports

a diverse and unique population of native

plants and animals.

Many forces threaten continued success of

this country’s agriculture, but one factor that

particularly threatens Western agriculture is

limited water. Water is essential for food and

fiber production, yet in much of this region,

low precipitation limits both plant survival and

growth. On land where precipitation is supplemented by water application, increasing competition from municipal and industrial users,

diminishing ground water supplies, higher

pumping costs, and declining water quality

cloud the future of agriculture.

This chapter describes the character of

Western agriculture and discusses its present

features and future outlook. Other chapters address the water issue explicitly as it relates to

agriculture.

29
30 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —— .— — —

CHARACTERISTICS OF ARID/SEMIARID LANDS

No universal definition of arid and semiarid

lands exists for agricultural purposes. Definitions based solely on total annual precipitation

fail to provide adequate information on its distribution throughout the year and on other climatic elements—e. g., temperature, humidity,

wind, and intensity and duration of sunlight—

that characterize the arid and semiarid environment. Definitions based on vegetation

types, soils, animal distribution, or land use are

similarly limited in application. Arid and semiarid lands, as used in this assessment, are those

lands where crop-water requirements exceed

the plant-available water (growing season precipitation plus soil water stored in the root

zone) by a significant amount,

Arid and semiarid lands characteristically

have predominantly clear skies, high average

wind speed, and low relative humidity. The

average annual precipitation is generally 20

inches or less. In the continental United States,

the arid and semiarid area includes parts of the

Figure 4. —Arid and Semiarid Regions of

the United States

17 Western States that lie between the 100th

meridian and the Sierra Nevada and Cascade

Mountain ranges (fig. 4). Offshore are scattered

arid and semiarid areas on the Hawaiian Islands, the Virgin Islands, and Puerto Rico. In

this assessment, the arid/semiarid lands of principal focus will be those located in the 17

Western States. *

Table 2 presents the land area by State for

the 17 Western States. Because information on

agricultural production is tabulated and classified by State boundaries, production figures

for some areas (particularly in the Pacific and

Great Plains regions) include crops and livestock produced under humid and subhumid

conditions.

*Although some resource management and technology aspects

of this assessment apply generally to any arid or semiarid situation, islands have unique natural resource characteristics and

agricultural capacity that vary by location and geology, A separate study of arid and semiarid islands is suggested.

Table 2.—Agricultural Land in the Western States,

by State, 1978

State

Great Plains:

Nebraska . . . . . . . . . . . .

North Dakota . . . . . . . .

South Dakota . . . . . . . .

Kansas. . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . .

Mountain region:

Wyoming . . . . . . . . . . . .

Montana . . . . . . . . . . . .

New Mexico . . . . . . . . .

Nevada. . . . . . . . . . . . . .

Colorado . . . . . . . . . . . .

Arizona . . . . . . . . . . . . .

Idaho ... , . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . .

Total land area

(rounded to

million acres)

49

44

49

52

168

44

62

93

78

70

66

73

53

53

Pacific region:

Oregon. . . . . . . . . . . . . . 62

California. . . . . . . . . . . . 100

Washington. . . . . . . . . . 43

17 Western States . . . . 1,158

31 Eastern States . . . . 739

Total . . . . . . . . . . . . . . 1,897

Agricultural land

(percent of total)

93

91

89

89

80

74

78

70

69

67

60

59

52

49

46

35

35

67

38

56

Note: Agricultural land includes cropland, grassland, pasture, and range.

SOURCE: H Thomas Frey, Major Uses of Land in fhe United States 1978, U.S.

Department of Agriculture, Economic Research Service, Agricultural

Economic Report No 487, 1982, appendix table 1
Ch. II—Agricu/tura/ Production in the Western United States ● 3 1

— ———

FEATURES OF WESTERN AGRICULTURE

Natural features, including climate and

weather patterns, soils, topography, and vegetation, differ markedly across the West. These

natural features, in turn, influence the types

of agriculture that are practiced and the crops

that are grown. *

Western Agriculture

in the National Context

Agriculture (farming and ranching) is the

dominant land use in the Western United

States. On average, the 17 Western States use

about 67 percent of the land for agriculture

compared with 38 percent in the East, This percentage changes across the region and ranges

from about 90 percent of the land area in some

States of the Great Plains to less than 40 percent in California and Washington (see table 2),

Unlike the Eastern States, a substantial

amount of land in the West is federally owned

(table 3), This percentage varies widely. In

* tl})[]endi x ~ ~jrf;sents more in furmat Ion on natural features,

ii I)(I ag r if u I t u ral production i n the arid and sem ia rid region.

Nevada, for example, over 85 percent of the

land is federally owned. In contrast, approximately 1 percent of the land in Kansas and

Nebraska is federally owned. Much of the public land is used primarily for livestock grazing;

a smaller portion is used primarily for timber

production, recreation, mining, or national security installations.

Products of Western agriculture constitute

a large share of the total income derived from

farming in the United States, In 1980, cash

receipts from marketing livestock and their

products and crops in the 17 Western States

accounted for approximately $59.3 billion, or

about 43 percent of the income derived from

farming in the United States (table 4).

The types of agricultural goods that produce

this income vary across the region and include

livestock products (e.g., meat, wool, hides,

milk, eggs, genetic material) and crops such as

wheat, barley, sorghum, cotton, hay, vegetables, field seed crops, fruits, and nuts. Within

the arid and semiarid area, there are regions

of crop specialization. In eastern Washington

Table 3.—Ownership of Land in the 17 Western States

Ownership

Federal Non-Federal

(000 acres) (000 acres) Percent Federal

17 Western” States . . . . . . . . . . . . . 368,108 -

789,503 32

31 Eastern States . . . . . . . . . . . . . . . . . . 33,759 704,693 5 ——.

SOURCE U S Department o; Agriculture, Soil Conservation Service, 1977 National Resources Inventory, Basin Statistics, revised

February 1980, table 1

Table 4.—Cash Receipts From Farm Marketing, 17 Western States, 1980a

(million dollars)

Agricultural product

State

— —

Livestock and products Crops Total

Total, 17 Western States . . . . . . . . . . . . .-. . $30,281 $29,0 $ 59,3

58 39

Total, United States . . . . . . . . . . . . . . . . . . $69,209 $68,8 $138,0

06 15

aOther income derived from farming (e g Government payments and nonmoney Income) are not included in totals

SOURCE U S Department of Agriculture Economics and Statistics Service Agricultural Outlook, March 1981 AO-63 p 25
32 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Photo credit: USDA-Soil Conservation Service

Western agriculture
Ch. II—Agricu/tura/ Production in the Western United States ● 3 3

.——— -. ——.

Box B.—Numbers, Numbers, Numbers

Congress, executive agencies, States, farm organizations, and the public rely on agricultural

statistics compiled by numerous Federal agencies. One of the most well-known and widely used

sources of a variety of agricultural data is the Census of Agriculture, conducted every 5 years by

the U.S. Department of Commerce, Bureau of the Census. Among the statistics that the census

collects are: land use, number of farms, crops harvested, average size of farms, characteristics of

farmers, and farm production expenses.

The U.S. Department of Agriculture (USDA) also has a major responsibility for collecting and

tabulating information on soil and water resources, land use, world agricultural production and

trade, farm income and expenses, crop supplies, market prices, and crop use. Much of this information is gathered independently by various agencies within the Department, but some data are

supplemented and coordinated with the Census of Agriculture and statistics from other executive

departments.

The large amount of agricultural data and the number of organizations that collect information have led to some problems for data users. First, coordination of data between organizations

that collect similar information is sometimes difficult. Second, there is often a delay between the

time the survey is taken and when it is compiled, summarized, and published. Another problem

is the accessibility of information. Agricultural data are dispersed throughout various USDA agencies and other departments. USDA makes an effort to compile these statistics, and each year the

Department publishes Agricultural Statistics. Information, however, focuses on agricultural commodities. Data on cropland and rangeland use, conditions of soil and water resources, and other

natural resources must be obtained from other sources, both within USDA and outside the

Department.

Finally, there are problems related to the nature of agricultural surveys. Data are collected and

tabulated along political boundaries, and it is very difficult to evaluate agricultural production under

arid/semiarid conditions V. humid/subhumid conditions in States where both climatic types exist.

Both the census and USDA have been criticized also because of the scope of their surveys. For

example, neither collects information on the extent of some agricultural practices such as organic

farming, “new crops, ” and livestock operations on public lands.

and Oregon, Idaho, and the Great Plains, for

example, large acreages of wheat, sorghum,

and barley exist. In California and other irrigated areas, farmers grow a wider mix of

products, including specialty crops such as

table vegetables, citrus fruits, wine grapes, and

melons, and row crops such as corn and cotton. Wyoming, Colorado, Nevada, and Utah

derive a major portion of their agricultural income from cattle and other livestock and their

associated products.

Certain crops grown in the West constitute

a significant share of the total acreage and

value of that crop for the entire Nation (tables

5 and 6). For example, nearly 85 percent of all

Table 5.—Selected Major Crops Harvested in the

17 Western States, by Acreage, 1978

Acreage Percent of

(000 national

Crop — acres) production

Wheat for grain ... , ... . . ., 46,811 86

Hay crops ... . . . . . . ... . . ., 29,116 47

Corn for grain or seed . . . . . . . . . . 13,870 20

Sorghum for grain or seed 11,620 90

Cotton . . . . . . . . . . . . . . . . . . . . . . . . 9,260 73

Barley for grain ., . . . . ... . . . 7,512 84

Oats for grain . . . . . . . . . . . . . . . . 4,487 44

Land in orchards . . . . . . . . . . . . 2,635 58

All vegetables harvested for sale ., 1,647 46

Field seed crops ., . . . . . . . 905 65

Irish potatoes ... , . . ... ... . . . . 867 62

Strawberries . . . . . . . . . . ... . . . . . 21 46

SOURCE U S Department of Commerce Bureau of the Census, 1978 Census

of Agriculture vol 1, c h 2, tables 29-34, 1981
34 . water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—. — —

Table 6.—Market Value of Major Agricultural Products

Sold, 17 Western States, 1978

Value Percent of national

Crop (million $) market

Livestock, poultry, and

other animal products .. .$27,461 46

Wheat for grain . . . . . . . . . . . . 3,947 83

Hay crops. . . . . . . . . . . . . . . . . 2,981 46

Fruits, nuts, and berries . . . . 2,834 61

Corn for grain or seed . . . . . . 2,689 19

Cotton . . . . . . . . . . . . . . . . . . . . 2,657 78

Vegetables, sweet corn,

and melons . . . . . . . . . . . . 1,973 60

Field seeds, hay, forage,

and silage. . . . . . . . . . . . . . . 1,343 58

Sorghums for grain or seed . 1,123 87

Irish potatoes ... , . . . . . . . . . 840 68

SOURCE U.S Department of Commerce, ‘Bureau of the Census, 1978 Census

of Agriculture, vol 1, ch 3, compiled from individual State tables, 1981

land used for wheat, barley, and sorghum production in the United States is located in the

17 Western States. Most of the agricultural land

used for the production of cotton, orchard

crops, and field seed crops is also located in

the region,

Export markets, particularly those in Japan

and other countries in the Far East, provide a

significant source of income for Western producers and represented about 30 percent of

cash receipts from farm marketing and about

40 percent of the total U.S. agricultural exports

in 1980 (table 7). The leading Western States

in terms of income derived from agricultural

exports are: California, Texas, Kansas, Nebraska, and North Dakota. California, Texas, Kansas, and Nebraska are also among the top 10

exporting States, by value, in the Nation. Texas,

for example, ranked first by value in exports

of cotton, grains, tallow, cattle hides, beef, and

live animals in 1980,

Western agriculture also generates employment in processing operations such as canning,

packing, and ginning, and in support services

such as equipment sales, transportation, and

farm and ranch supply businesses (table 8).

Many of these enterprises are rural-based and

are an important element of rural life (see

discussion of rural economies and agriculture

in ch. V].

.— — — — — —

Table 7.—Agricultural Exports in the 17 Western

States, by Value, October-September, 1979-80

and 1980-81 (million dollars)

Region 1980 1981

17 Western States . . . . . . . . . . . , . . . . . $16,662 $17,656

Total United States . . . . . . . . . . . . . . $40,481 $43,789

17 Western States,

percent of United States. . . . . . . . . . 41 0/0 40%

SOURCE U S Department of Agriculture, Economic Research Service, Foreign

Agricultural Trade of the United States, March/April 1982, table 17.

Types of Agriculture in the

Arid and Semiarid Region

Agriculture is shaped by the natural environment—landscape, climate, and soils. Production technologies, landownership patterns,

distance to livestock and crop markets, economic conditions, individual choice, and social

custom also influence agricultural production.

Agricultural production in the arid and semiarid region includes three broad types of agricultural practices: rangeland agriculture,

dryland farming, and irrigation agriculture.

Each has a different level of resource use and

output (fig. 5). Rangeland agriculture occurs in

areas where the native vegetation—predominantly grasses, grasslike plants, forbs, * and

shrubs—are used commonly for grazing domestic livestock. Such areas are generally unsuitable for cultivation because they are too

cool, too hot, too arid, or have soils too shallow

or infertile to raise crops. Dryland farming is

crop production through cultivation of the

land. It relies on precipitation to supply plantwater needs. Irrigation agriculture supplements precipitation with additional water, primarily providing water for plant growth that

is not normally supplied during the growing

season,

The proportion of land used for each practice varies greatly across the Western States.

Rangeland agriculture is the most land-extensive practice, followed by dryland farming and

irrigation agriculture.

* Herbaceous plants other than grasses.
— .

—.——

Ch. II—Agricultural Production in the Western United States 35

Table 8.—Agricultural Services:a Number of Establishments,b

Gross Receipts and Payroll, by State, 1978

Number of Gross receipts Annual payroll

State establishments (in $000) (in $000)

Great Plains:

Texas ... . . . . ... . . . . . . 2,436 $ 281,493 $ 96,476

Nebraska . . . . . . . . . ... . . 554 48,494 14,385

Oklahoma . . . . . . . . . . . . . . . . 562 36,447 8,821

Kansas . . . . . . . . . . . . ... ... . 754 41,937 8,599

South Dakota . . . . . . . . . . . . . . . . 313 16,516 3,921

North Dakota . . . . . . . . . . . . . . . . 243 15,571 3,213

Mountain region:

Arizona . . . . . . . . . . . . . . . . . . . 441 104,250 41,705

Idaho . . . . . . . . . . . . . . 352 45,853 10,503

Colorado . . . . . . . . . . . . . . . . . 355 31,981 8,477

Montana . . . . . . . . ... . . . . . . 238 13,528 2,971

New Mexico . . . . . 118 8,741 2,686

Wyoming . . . . . . . . . . . . . . . . . . . 79 4,197 1,394

Utah . . . . . . . . . . . . . . . . . . ., 98 5,905 1,120

Nevada, . . . . . . . . . . . ..., . . . . . 40 2,544 490

Pacific region:

California. . . . . . . . . . . . . . . . . . . . 3,043 1,034,223 452,186

Washington, . . . . . . ..., . . . . 387 78,732 24,904

Oregon. . . . . . . . . . . . . . . . . . 331 31,197 8,943

17 Western States ., . . . . . . . . . . 10,344 1,801,609 690,794

United States . . . . . . . . . . . . . . . 20,595 2,936,208 2,134,248

aAgricultural services consistt of soil preparation services; crop services; veterinary services for cattle, hogs sheep, goats,

and poultry, animal services (except veterinary) for cattle, hogs, sheep, goats, and poultry; farm Iabor; and management services

bEstablishments having a dollar volume of business less than $2,500 are omitted.

SOURCE U S Department of Commerce, Bureau of the Census, 1978 Census of Agriculture, vol 3, table 23, 1981

Agricultural practices are dynamic. For example, an area can shift over a period of years

from rangeland to dryland farming to irrigation. If irrigation water becomes limited and

dryland agriculture is possible, a producer may

choose to switch to crops that require less irrigation water, supply less than full water requirements to a crop, revert to dryland farming, or reseed an area and use it for grazing

purposes. At the same time, a single farm or

ranch can combine different types of agricultural practices. An individual can graze livestock on land not suited for cultivation but farm

other areas where the soils are more fertile and

where precipitation or irrigation water is sufficient for crop production.

The way agricultural practices change over

time is evident in some of the Great Plains

States. In 1944, about 2 million acres of land

in Kansas, Oklahoma, Nebraska, and Texas

were irrigated; by 1974 this total had grown to

about 13 million acres (fig. 6), The shifts among

agricultural practices continue. Irrigated acreage in the southern Great Plains (primarily

Texas) decreased by over a half-million acres

between 1974 and 1979 because of depletion

of the Ogalalla aquifer and because of highenergy costs (11). As a second example, in the

past 3 years, nearly 450,000 acres of grasslands

in Colorado (approximately 700 square miles)

that were previously used as range have been

plowed in preparation for dryland farming (l).

Another 700,000 acres of grasslands in South

Dakota (approximately 100 square miles) have

been plowed in the last 9 years (9). This trend

has alarmed Federal and State officials who

fear that this land is too fragile for intensive

cultivation* and that the “Dust Bowl” days of

the l930’s will return if irrigation water is in

short supply or if a lengthy period of dry weather occurs.

“Legislation has been introduced in Congress and in some

States with the intent of curbing this practice. See also ch. XII.
36 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 5.—Schematic of Western Agriculture

Rangeland Agriculture

After the Western territories were acquired

by the Federal Government in the 1800’s, much

of the land was in the public domain. One value

that became apparent to early inhabitants was

its use for breeding and feeding domestic livestock, mainly sheep and cattle. Gradually, the

livestock industry advanced throughout the

Western region to supply settlers’ needs and

to fulfill the demand from Eastern States.

Rangeland is often classified by vegetation

type: grassland or prairie types, desert shrub,

chaparral, and understory herbage in both coniferous and hardwood forests (fig. 7). The natural productivity of a particular site varies

greatly throughout the region and depends on

precipitation, soils, and management.

In general, rangeland agricultural areas produce forage for livestock. In addition, many of

these areas are located in mountainous regions

where surface runoff provides water to streams

and rivers. Rangelands serve, too, along with

forests, as the most productive and largest habitat for wildlife in the United States because

they are managed less intensively than are

other types of ecosystems. Federally owned

rangelands are mandated to be managed for
Ch. II—Agricultural Production in the Western United States . 37

Oklahoma, Texas

Kansas, Nevada

multiple products—grazing, timber, mining,

water, and recreation.

Dryland Farming

The United States contains an estimated 350

million acres (546,000 square miles) of semiarid

land (2]. This area encompasses the Great

plains, eastern Oregon, eastern Washington,

northern and southern Idaho, parts of western

Colorado, Utah, and parts of the California

Valley. Some of this land is suitable for crop

production, especially using dryland methods.

In dryland farming, crops must be able to

grow and produce under conditions of low

precipitation. The number of crops currently

adapted is limited. Wheat and barley, sorghum,

millets, seed legumes (e. g., dry beans, dry peas,

and lentils), safflowers, and sunflowers are produced commonly. The choice of a crop is further limited because some crops are adapted

narrowly to certain climatic conditions (e. g.,

seasonal distribution of precipitation, winter

and summer temperatures, and length of growing season).

The most extensive dryland crop area in the

semiarid region of the United States is planted

—

Figure 7.— Vegetation Types in the Arid and Semiarid

Regions of the United States

SOURCE

in wheat, which provides the highest cash income of all dryland crops. The major producing areas include the Great Plains, eastern

Oregon, eastern Washington, and Idaho. Depending on climatic characteristics, different

classes of wheat (i.e., hard red winter, hard red

spring, durum, or soft white wheat) are grown

in certain areas.

Barley can be grown in many areas where

wheat is produced but tends to be less tolerant

of cold weather. Much of the dryland region

in California produces barley, and the crop is

used for animal feed or malt.
38 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

.— —

Where wheat and barley production is lim- Irrigation can have several purposes. Its priited by low precipitation or hot temperatures, mary aim is to supply water to plants so that

farmers can grow sorghum, millets, and seed yields are not limited by insufficient water.

legumes. Grain sorghum is especially suited to Other purposes include:

parts of the southern and central Great Plains,

where growing seasons are long. It can be used ●

for animal feed or grazed by livestock. Other

crops such as pinto beans, dry peas, lentils, safflowers, and sunflowers are locally important. ●

For example, dry peas are grown in the Pacific

Northwest and sunflowers are produced in

North Dakota and western Nebraska. ●

●

Irrigation Agriculture

Irrigation agriculture accounts for roughly ●

50 million acres of agricultural land in the 17

Western States, or about 6 percent of the total ●

agricultural land in the region (table 9). California is the leading State in number of acres irflushing soluble salts out of the soil,

thereby preventing their harmful effects on

plants;

preventing severe freeze or frost damage

to orchards, citrus nurseries, strawberries,

ferns, and subtropical fruits;

seed-bed preparation;

waste treatment of effluents from food

processing industries and municipal sewage facilities;

reducing heat stress in plants by wetting

the foliage; and

facilitating harvest of root crops (e.g., sugar beets, potatoes) (6).

rigated, followed by Texas, Nebraska, Idaho, Irrigation is an economically important pracand Colorado. In 1978 more than 80 percent tice in the arid and semiarid region because

of the harvested cropland in Nevada, Arizona, it allows crop production where it might not

and California was irrigated; from 50 to 80 per- otherwise be possible. Furthermore, with its

cent of the harvested cropland in Idaho, Wyo- value in controlling soil water and in reducming, and Utah was irrigated. ing the risk associated with crop production,

Table 9.— Nonirrigated and Irrigated Cropland,a 17 Western States, 1977

All cropland

Non irrigated irrigated Percent of total

State (000 acres) (000 acres) cropland irrigated

. —

Great Plains:

North Dakota. . . . . . . . . . . . . . . . . . . . . 26,835 78 <1

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . 25,631 3,175 11

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . 22,510 7,929 26

South Dakota . . . . . . . . . . . . . . . . . . . . 17,684 472 3

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . 13,794 6,905 33

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . 11,073 710 6

Mountain region:

Montana. . . . . . . . . . . . . . . . . . . . . . . . . 13,294 2,061 13

Colorado . . . . . . . . . . . . . . . . . . . . . 7,699 3,394 31

Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,743 3,547 56

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . 1,320 1,650 56

New Mexico . . . . . . . . . . . . . . . . . . . . 1,203 1,079 47

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655 1,160 64

Arizona. . . . . . . . . . . . . . . . . . . . . . . . . . 145 1,167 89

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . 4 1,103 100

Pacific region:

Washington . . . . . . . . . . . . . . . . . . . . . . 6,179 1,772 22

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . 3,139 2,009 39

California . . . . . . . . . . . . . . . . . . . . . . . . 1,920 8,153 81

Total, 17 Western States. . . . . . . . . . . 155,828 46,364 23

Total 48 States . . . . . . . . . . . . . . . . . . . 357,027 55,594 13

aCropland Includes cultivated cropland, pasture, hay land, orchards, and vineyards.

SOURCE U S Department of Agriculture, Soil Conservation Service, 1977 National Resources Inventory. Basic Statistics, revised

February 1980. table 3
Ch. II—Agricultural Production in the Western United States ● 3 9

. .—

Box C.—Rainfall and the Western Settler

One element that strongly shaped agriculture in the Western States was the environment, particularly limited precipitation. Explorers to the region in the early 1800’s noted that the West was

unsuited for farming operations and called it “A Great American Desert.” Some individuals who

later attempted to farm without irrigation affirmed this notion–the weather was unpredictable;

precipitation was often erratic, scant, and poorly distributed; and temperatures were extreme.

Despite the crop failures sustained by many farmers and the powerful presence of the cattle

industry, hopes for a more intensive type of agriculture than ranching remained alive. Some colorful myths developed that promised rain to the farmers:

● rain would follow the plow because evaporation would increase from worked soil,

. rain would follow the train because raindrops would form around smoke particles,

● rain would follow the telegraph because of electricity in the air,

● rain would follow a military battle (experiments were even conducted in Texas with explosives

and cannons—without success], and

. rain would follow settlement because the people were good and worthy with a destiny to

fulfill.

Farming practices in the West strongly reflect this past experience. Dryland farming techniques

eventually evolved that conserved precipitation during the winter months for use during the growing

season. Crops were selected that did well despite the low amounts of water. Water supplies were

developed (by reservoir and canal construction) to enable crop production in areas that would have

little potential for farming otherwise.

farmers who irrigate generally have higher and

more stable yields than do dryland farmers, *

Moreover, such producers have a wider choice

of crops. * * These crops include corn, cotton,

wheat, sorghum, high-value specialty crops

such as fruits, nuts, berries, vegetables, sweet

corn, and melons, and field seed crops (table 10).

Structure of Western Agriculture

Farm Size and Ownership

Many factors influence farm/ranch size and

ownership patterns including natural resources, availability of capital, export demand

for crops, availability of nonfarm employment,

commodity programs, credit availability, and

tax rules. * * * In the Western States, farms and

* [’rt~[i[~rl(.k and Hanson (5) compared yields among western

d r~ la n(l II I~d i rri~a ted crops of corn, sorghum wheat, and cotton to th{’ I{a\t. Irrigated t:rops had significantly higher jrields

IIf’r ,1( r(~ than ~’ithf;r {Ir} lan(i cro]]s or crops grown in the East.

F’or example, with lrri,qation, average yields for corn increase(i

from 48 to 1 I 5 bushels per acre. In the East, atrerage ~ields were

t){j I)ushf;]s pf?r a( rt’.

* * The wide se]er.tion of crops atailahle to irrigators is reflected

i n the fact that in cal iforn ia, o~er zoo commercial crops are

Rrown.

* * “This ~iiscussion is Iargel} from Schertz, et al. (IO].

ranches tend to be larger than in the rest of the

United States; dryland farms and ranches tend

to be larger than irrigated areas.

For purposes of this discussion, the farming

regions are as follows:

1. the Great Plains include North and South

Dakota, Nebraska, Kansas, Oklahoma,

Texas, Colorado, Wyoming, and Montana;

Z. the Southwest includes California, Nevada, Utah, Arizona, and New Mexico; and

3. the Northwest includes Washington,

Idaho, and Oregon.

Among the Western States, as in the rest of

the United States, there has been a trend

toward fewer but larger farms. In the Great

Plains in 1978, the average farm size was about

900 acres (over two times the national average

of 415 acres). Cash receipts per farm were

about $55,000 (the national average was about

$44,000). Most of the farms in the region were

less than 500 acres in size, but about one-fifth

(about 100,000 farms) were over 1,000 acres.

Over one-half of the farms were owned by an

individual or family; many operators also

rented land.
40 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 10.— Irrigated Acreage of Selected Crops, 17 Western States, 1978

Acres harvested Acres irrigated Percent of

Crop (000 acres) (000 acres) crop irrigated

Hay Crops . . . . . . . . ~. .: . . . . . . . . . . . . . 29,116 8,954 31

Corn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13,870 7,850 57

Cotton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9,260 4,555 49

Wheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46,811 2,987 6

Orchard crops . . . . . . . . . . . . . . . . . . . . . . 2,635 2,306 87

Sorghum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,620 2,019 17

Barley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7,512 1,964 26

All vegetables harvested for sale . . . . . . . . . 1,647 1,445 88

Irish potatoes . . . . . . . . . . . . . . . . . . . . . . . . . . 867 716 83

Field seed crops . . . . . . . . . . . . . . . . . . . . . 905 303 33

Oats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4,487 223 5

Strawberries . . . . . . . . . . . . . . . . . . . . . . . . 21 18 86

SOURCE US Department of Commerce, Bureau of the Census, 1978 Census of Agriculture, vol 4, ch 1, tables 9.13, 1981

Farm size in the Southwest, as measuredly

resources controlled and output per farm, far

exceeds the U.S. average. In 1978, average farm

size was 1,300 acres and cash receipts per farm

totaled about $130,000. Looking only at crop

production, the value of crops sold per farm

in the Southwest was 3 I/Z times the U.S. average. Also of interest was the distribution of

farms and sales among size classes. In 1974 the

Southwest had a slightly higher proportion of

small farms (less than 180 acres) than did the

rest of the United States (reflecting specialtycrop production); however, more than 55 percent of Southwestern farms exceeded 1,000

acres, compared with 34 percent for the United

States, Three percent of all farms had more

than $500,000 in annual sales and produced 60

percent of the cash receipts from farming.

Corporate farms (both family held and nonfamily owned) are another important feature

of the Southwest. In 1978 corporate farms controlled nearly 20 percent of Southwestern farmland, Their role varies with crop and area. For

example, in the southern San Joaquin Valley

of California, conglomerates operate some

large producing-processing-marketing farms.

These farms produce a large variety of crops,

including tree fruits, nuts, and vegetables.

Characteristics of Northwestern farm production are difficult to assess because of the

diverse crop-production capabilities in the

region. In 1978 average farm size was slightly

over 500 acres; however, farm size tended to

be much lower along the coastal areas than in

the intermountain irrigated area or dryland

farming region east of the Cascade Mountains.

Average farm sales were approximately $75,000.

A majority of farms were owned by an individual or family.

Role of Labor

Since World War II, one of the most dramatic

shifts in agriculture has been the substitution

of capital goods (e. g., tractors and other farm

machinery, farm chemicals, and irrigation water) for labor. On the Great Plains, for example, fewer farms and the development of larger

tractors and other machinery have reduced

farm labor requirements and the number of

farmworkers. Over the period from 1960 to

1977, the number of farmworkers declined

from 1.25 million to 785,000. About one-fourth

of these workers were hired; the rest of the

labor force consisted of family farm labor.

Where high-value specialty crops are grown,

considerably more hired labor is used. For example, in the Southwest in 1977, the bill for

hired labor totaled $1.9 billion, 26 percent of

the U.S. hired labor charge. Of the total farm

work force in the region, 69 percent was hired

labor, compared with 31 percent owner and

family labor. Comparable national totals were

reversed.

Much has been written about the hired labor

force in the Southwest. In general, it is char-
Ch. II—Agricultural Production in the Western United States 41

.

acterized by its impermanence—80 to 90 per- of 25 and 44 have an average of 9 years of

cent of hired labor work less than 150 days. schooling (4). Many are minorities, and these

Furthermore, of all the occupational classes in workers may find little alternative employment

the United States, farm laborers are the least outside of agriculture.

educated. Male farm laborers between the ages

TRENDS

The long-term future of Western agriculture

is uncertain. The elements that have shaped its

past—natural resources, people, science and

technology, economics, and Government policies—will invariably affect its future. New considerations, unknown or discounted as unimportant at present, may influence the future

direction of Western agriculture. Examples of

these elements include climatic change, increased foreign and corporate ownership of

farmland, energy shortages, increased water

restrictions on agriculture, resource degradation, world food shortages or famine, widespread crop failure (domestically or internationally), international conflicts, or other crises.

Irrigation agriculture raises particular concern at present. The West supplies the Nation

with important foodcrops, especially perishables, and most of these crops are irrigated. *

Furthermore, mild winter temperatures and

fertile soils give some areas of the region (e.g.,

California and Arizona) a virtual monopoly in

producing numerous specialty crops (e.g., almonds, walnuts, and wine grapes). However,

large tracts of land produce corn, sorghum,

alfalfa, wheat, and lesser grains that are produced in abundance elsewhere.** In recent

years, some of these commodities have been

in surplus. Moreover, decisionmakers at all

levels of government are concerned that the

water-short West may not be able to sustain

current levels of population growth, accommodate new energy and industrial development, and maintain its irrigated acreage (see

discussion of completing uses in ch. V). Individuals and groups that support environmental conservation worry also about the

effects of irrigation on land, surface flows, and

wildlife. Depletion of ground water resources,

especially in the southern Great Plains, threatens not only the well-being of agricultural producers who use this water but also rural communities that are agriculturally based. Furthermore, current use of easily tapped ground water diminishes the possibility of using this

resource in the future. Added together, these

factors lead many analysts to believe that irrigation in its present form will not continue

to make the contributions to agricultural

growth that it has in the past (5,8).

The social ramifications of irrigation are less

well understood and more difficult to assess,

but important questions nonetheless. Irrigation

agriculture often affects farm size and ownership dramatically—changing land use patterns,

increasing land values, and limiting ownership

to large farmers and ranchers, outside investors, or corporations that can more easily

afford the high risks and high investments irrigation often necessitates (7). Reliance on

migrant farm labor, especially in fruit and

vegetable crop production in the Northwest

and Southwest, raises questions about income

equity, housing standards for migrant workers,

and immigration policies (12).

A second set of issues affects agricultural

land and its competition with nonagricultural

uses: urban development, recreation, and

transportation. Estimates indicate that from

1967 to 1977, some 2 million to 3 million acres

of agricultural land (cropland, pasture, range25-160 0 - 4 : QL 3
42 ● Water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—— ——— . .— .

Box D.—Reducing Agricultural Surpluses

During the 1981 and 1982 crop years, U.S. and world grain production reached record levels.

Favorable weather contributed to this increase. At the same time, the demand for U.S. agricultural

products slowed, and domestic grain stocks ranged to new highs mainly caused by weak economic

conditions in the United States and in other parts of the world, financial instability in several countries, a strong U.S. dollar, market losses related to the Soviet embargo, continued East-West tensions, and restrictive marketing practices in some foreign markets. For farmers in this country,

the high grain stocks meant reduced crop prices; in calendar 1982, average domestic prices for

wheat and coarse grains dropped to their lowest levels since 1979.

Following these events, the administration launched several programs to reduce stock, lower

Federal commodity payments, and bolster prices. In 1982, USDA offered farmers an acreage-reduction program in an effort to curb production. Under this program, farmers voluntarily agreed to

reduce the number of acres they would plant in a particular crop (e.g., corn, wheat, cotton) by

a specified percentage. In return, they became eligible for Federal price support benefits. However,

good weather and the late program announcement negated its intended effects.

For 1983, the program was expanded to include paid diversion (i.e., farmers who comply with

the voluntary acreage reduction may further reduce their acreage and receive cash payments), an

expanded export credit program, and a payment-in-kind (PIK) program. The novel PIK program

attracted much interest from the public. Under this program, farmers who removed from production additional acres over what they agreed to take out under current acreage-reduction programs

received as payment a certain amount of the commodity they would have grown on these acres.

The commodity then became the property of the individual and could be disposed of in any way

the farmer wished. Crops of wheat, corn, grain sorghum, cotton, and rice were included in PIK.

Secretary Block, in detailing features of the program, noted, “We have a threefold objective

with PIK—reduce production, reduce surplus stockholdings, and avoid increased budget outlays

that would otherwise be necessary under price support programs.” Furthermore, he stated, “It

is unlikely our surplus will be substantially reduced any time soon by increased exports. PIK is

aimed at bringing supply more in line with demand.”

SOURCES: USDA Payment in Kind Fact Sheet, 1983. Remarks Secretary John R. Block, Ian. 11.1983. Economic Research Service, World Agriculture Outlook

and Situation, WAS-3I, March 1983.

. 

land, and forest) were converted each year to

nonagricultural uses (3). About one-third was

in active use. Two points become evident. First,

with current low prices of many farm commodities (particularly grains and cotton), many

farmers are facing financial ruin. Some Western farmers may leave agriculture, thereby easing the way for additional land conversion,

which may ultimately affect the Nation’s capacity to produce food and fiber. Second, expansion of urban areas often occurs at the expense of local agricultural land. Farmers may

decide to retire from agriculture or move their

operations to other lands, which may be less

productive and more erosive, and which may

entail higher production costs.

A third but related set of issues affects agricultural practices in the region. Will the shift

from rangeland agriculture to dryland farming

or irrigation on privately owned lands create

another “Dust Bowl”? If these areas are converted but later abandoned, how can they be

rehabilitated and made productive again, and

who should bear the costs of reclamation?

New technologies and Government policies

(including water, food, export, and agricultural

research policies) may drastically shape tomorrow’s agriculture in the arid and semiarid

region. Traditional agricultural practices may

change. Irrigation, as it is practiced today, may

become less important; producers may move
Ch. II—Agricu/tura/ Production in the Western United States “ 43

away from reliance on a single crop for their

income toward multiple-use of croplands and

rangelands. Some native plants and animals

may be used more intensively for food, fiber,

energy, and industrial feedstocks. Greenhouses

—— -——.

and fish enclosures may gradually become

more common, capturing the incoming solar

radiation and highly concentrating food production over small areas of land.

CHAPTER II REFERENCES

1. Anonymous, “Where is That Rain on the Western Plain?” The Kansas City Times, May 25,

1982.

2. Brengle, K. G., Principles and Practices of’ Dryland Farming (Boulder, Colo.: Colorado Associated University Press, 1982).

3. Conservation Foundation, State of the Environment 1982 (Washington, D. C.: Conservation

Foundation, 1982].

4. Finan, Timothy J., Downing, Theodore E., and

Bennett, John W., “Social Impacts of Water

Technology Changes on Western Populations,”

OTA commissioned paper, August 1982.

5. Frederick, Kenneth D., and Hanson, James C.,

Water for Western Agriculture (Washington,

D. C.: Resources for the Future, 1982).

6. Jensen, Marvin E., “Overview-lrrigation in

U.S. Arid and Semiarid Lands, ” OTA commissioned paper, October 1982.

T. Johnson, Stanley S., and Jesse, Edward V., “The

Southwest, ” Another Revolution in U.S. Farming? U.S. Department of Agriculture, Economics, Statistics, and Cooperatives Service,

Agricultural Economic Report No. 441, 19T9,

pp. 362-403.

8. Langrone, William Franklin, “The Great

Plains,” Another Revolution in U.S. Farming?

U.S. Department of Agriculture, Economics,

Statistics, and Cooperatives Service, Agricultural Economic Report No. 441, 1979, pp. 335-361.

9. Laycock, William A., Range Ecologist, Ft. Collins, Colo., personal communication, 1983.

10. Schertz, Lyle P,, et al., Another Revolution in

Farming? U.S. Department of Agriculture, Economics, Statistics, and Cooperatives Service,

Agricultural Economic Report No. 441, 1979.

11. Texas Department of Water Resources, Inventory of Irrigated Acres in Texas, Report 263, October 1981,

12. Torres, Luis, Program Director, Northern New

Mexico American Friends Service Committee,

Espanola, N. Mex., personal communication,

1982.
Water Supply

and Use

WesternUnited

in the

States
..— — —

Page

Survey of Federal Agencies Involved in Water . . . . .$ ....,.,........0,,...,.,,, 47

Discontinued Federal Efforts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Ongoing Federal Efforts .o**o. .,, .*, ..** ... .., ,., *.. ... .., ... ... .,. ... ,,o, 47

Water Supply: The Hydrologic Cycle . .........,.....,,.....,.,...,,,,..,.0,. 48

The Components **. ... **. o.o. **. *.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Variability in the Hydrologic Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Water Planning, Data Collection, and Analyses . ..,.,.....0...,....,,,....,,.0 67

Evolution of the Federal Role ● , . . . . ., . . . . ,0, , ., . .,, .,, ., . . . . . . . . . . . . . . . . . . 67

Data Collection and Analysis Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Water Use in the Western United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Relationship Between Supply and Demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Water Supply and Use Patterns . . . . . . * . ., ., . * . * ., . .,, . . . . . . . . . . . . . . . . . . . . . 72

Future Energy Demands for Waste Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Chapter III References ..*. .*. .o. **. *.** . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

List of Tables

Table No. Page

11. Federal Water-Data Collection Agencies ● , *, ., . . . . . . ., .,, * . ., . .,, . ....,*.*. 69

12. Estimates of Average Annual Runoff in the Western United States, 1975 . . . . . . 70

13. Estimates of Total Water Withdrawals in the Western United States, 1975 . . . . . 70

14. Per Capita Water Use in the Eastern and Western United States . . . . . . . . . . . . . 72

15. Water Supply and Use, Including Off-Channel

and Hydroelectric Generation, by Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

16. Western Water Resource Subregions Where Offstream

Use Exceeds Total Streamflow ● *.** ..o. ...0 e**. . e**.*......*......*...*.. 76

List of Figures

Figure No. Page

8. The Hydrologic Cycle .o. ..** *0. *o. o*. .*o. .,*. ..*. *.. *.** .., *o, *.6. .$. .o 49

$. The Water Resources Regions of the Western United States . . . . . . . . . . . . . . . . . 51

10. Major Landforms of the Western United States ● . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

11. Average Annual Precipitation of the United States . . . . . . ., * . . . . . . * **,.*..** 54

12. Average Annual Snowfall in the Western United States . . . . . . . . . . . . . . . . . . . . . 55

13. The Relationship Between Precipitation and Potential Evapotranspiration . . . . . 57

14. Potential Evapotranspiration in the Western United States. . . . . . . . . . . . . . . . . . . 58

15. Major Ground Water Resource Regions of the Western United States . . . . . . . . . 59

16. Average Streamflow for Major U.S. Rivers, 1941-70 . . . . . . . . . . . . . . . . . . . . . . . . 60

17. The Spatial Pattern of Annual Streamflow ● . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

18. The Annual Variability of Streamflow Volume, Upper Colorado River, 1920-80. 63

19. Average Monthly Runoff, Clarks Fork, Yellowstone River . . . . . . . . . . . . . . . . . . . 64

20. Potential Errors in Water Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

21. River Basin Commissions and Other Regional Water Agencies

Abolished in 1$81 ..*. *.. .0*0 **. *.. *0** *0** ...0 *.. . . . . . . . . . . . . . . . . . . . . . 68

22. Total Offstream Water Withdrawals, by States, 1980 . . . . . . . . . . . . . . . . . . . . . . . . 71

23. Water Resource Subregions Where Total Water Use

Exceeds Streamflows in an Average Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

24. Ratio of Offstream Consumptive Use to Streamflow During August. . . . . . . . . . . 77

25. Monthly Relationship Between Water Supply and Use

for Three Western Rivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Chapter III

Water Supply and Use in the

western United States

The existing relationship between water supply and use in the Western United States determines both the extent of the supply/use problem and the potential of any individual technology to alleviate current or anticipated problems. Regional water-use patterns, that have

evolved as a result of the spatial and temporal

variability of water supplies, are linked in a

complex fashion by the hydrologic cycle. The

understanding of the hydrologic cycle and of

current or potential water problems is inextricably tied to the way in which relevant data

are coIlected and analyzed.

This chapter provides an overview of the existing water resources and current water uses

in the Western United States. It is the foundation for assessing water-related technologies in

succeeding chapters. The purpose of this chapter is: 1) to outline the major components of

the hydrologic cycle, their interrelationships,

and their variability as they are altered naturally or technologically; 2) to discuss the adequacy

of data available on the quantities of water in

various components of the cycle and problems

of water-data acquisition and analysis; and

3) to evaluate, in the context of available data,

the nature of the supply and demand relationships of the major river systems of the Western

United States. The chapter begins with a review of the major Federal agencies dealing

with water.

SURVEY OF FEDERAL AGENCIES INVOLVED IN WATER

Various agencies within the Federal Government have been involved in water and waterresources management since the United States

was formed. Generally, these activities have

been oriented toward supporting the specific

mission and program of each agency.

Discontinued Federal Efforts

Water Resources Council: Established by the

Water Resources Planning Act of 1965 (Public

Law 89-90); produced a first National Water

Assessment in 1968, based mainly on data compiled and analyzed by major Federal agencies;

produced second National Water Assessment

in 1978 which updated information on the Nation’s water resources and which attempted to

determine the adequacy of water supplies for

future use; agency functions essentially abolished in 1981 with termination of funding.

National Water Commission: Established by

Act of Congress (Public Law 90-515) for a fixed

term; produced in 1973 a report to the President, Water Policies for the Future, that considered the Nation’s water-resource supplies

and uses and outlined several alternative futures and possible actions for water-resource

development to the year 2020; Commission terminated with production of report.

Office of Water Research and Technology:

Established within the Department of the Interior; sponsored State programs of research,

development, and demonstration in the fields

of water and water-related resources generally through State water research institutes; abolished by Reagan administration in early 1980’s.

Ongoing Federal Efforts

Currently, Federal responsibility for waterdata acquisition, planning, and management

of particular relevance to this assessment includes the Departments of Agriculture (USDA),

Commerce (DOC), Defense (DOD), and Interior

47
48 ● water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

(DOI) and the Environmental Protection Agency (EPA). The key mission and water-related

activities of the principal agencies within each

Department are summarized below from Plans

for Water Data Acquisition by Federal Agencies Through Fiscal Year 1983 (11),

Agricultural Research Service (USDA):

Conducts research on water-use technologies

for agriculture, analyzes data on agricultural

water use, and develops practices involving use

of soil, water, and air resources for agriculture.

Forest Service (USDA): Maintains responsibility for water resources that are derived

from Forest Service lands, protects tributary

waters, and conducts water-resource research

relevant to the long-term productivity of forests

and rangelands.

Soil Conservation Service (USDA): Collects

water-related data, including snow data, for

downstream agricultural users and undertakes

soil, water, and related resource projects with

farmers, ranchers, and groups of individuals

to improve production and protect the resource

base.

National Oceanic and Atmospheric Administration (DOC): Includes the National

Weather Service; provides water data in support of basic hydrographic surveys, research,

water regulations, specialized users, and safe

navigation; conducts some weather modification work.

U.S. Army Corps of Engineers (DOD):

Plans, designs, constructs, and operates waterresource projects throughout the United States;

performs similar analyses for nonstructural

projects.

Bureau of Land Management (DOI): Manages water resources on the public lands administered by the Bureau and conducts inventories and analyses of quality and quantity of

surface- and ground-water resources on public

lands.

Bureau of Reclamation (DOI): Plans and

constructs water projects in the 17 Western

States to provide flood control, water for irrigated agriculture, municipal and industrial

water supplies, and hydroelectric generation;

involved in some weather modification work.

Fish and Wildlife Service (DOI): Responsible for overseeing national interests in the conservation of fish and wildlife and their habitat;

provides ecological expertise to water-resource

planning, development, and management activities.

U.S. Geological Survey (DOI): Collects and

analyzes water data, operates the National

Water Data Exchange (NAWDEX) program,

and provides hydrologic information for the

use and management of the Nation’s water

resources.

U.S. Environmental Protection Agency:

Conducts research and demonstration projects

on water quality, monitors water quality, establishes and enforces water-quality standards,

and defines water pollution controls.

WATER SUPPLY: THE HYDROL0GIC CYCLE

present agricultural practices in the arid and technologies that agricultural production has

semiarid portions of the Western United States been feasible.

are the result of complex interactions involving both the biophysical environment and hu- In arid and semiarid areas, both temporal

man modification of and adaptation to that en- and spatial inequities in the distribution of

vironment. Water is one of the primary limiting water lead to shortages. These shortages may

factors in this environment, and it is general- be chronic for certain areas, such as the deserts

ly only where this limitation has been over- of the Southwest, or seasonal in areas that

come by rangeland, dryland, and irrigation derive the bulk of their water supply from the
Ch. III—Water Supp/l and Use in the Western United States . 49

— -. — — —

annual spring snowmelt and runoff. Water- may be considered the central concept in hy -

related problems are site-specific to some ex- drology.

tent. This geographical aspect of the problem

varies with agricultural practices and depends, The components of the hydrologic cycle are:

to some extent, on which water processes are ●

involved.

The fundamental, unifying concept in the

study and understanding of water is the hydrologic cycle (fig. 8). The cycle is the conceptual ●

model that relates the interdependence and

continuous movement of all forms of water

through the vapor, liquid, and solid phases. It

precipitation: Water added to the surface

of the Earth from the atmosphere. It may

be either liquid (e.g., rain and dew) or solid

(e.g., snow, frost, and hail).

Evaporation: The process by which a liquid is changed into a gas. In the context

of the hydrologic cycle, the most important form

Figure 8. —The Hydrologic Cycle

of evaporation is probably that

Water passes continuously through this cycle from evaporation from the oceans into the atmosphere through

precpitation onto the continents and eventual runoff Into the oceans Human use of water may modify this cycle at virtualIy every point

SOURCE H Hengeveld and C DeVocht Urban Ecology 6(1-4) 19, 1982
50 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

●

●

●

s

which takes place from the seas and

oceans. This is the main source of water

on land areas.

Transpiration: The process by which

water vapor passes through a living plant

and enters the atmosphere.

Infiltration: The process whereby water

soaks into, or is absorbed by the surface

soil layers.

Percolation: The downward flow of water

through soil and permeable rock formations to the water table.

Runoff: The portion of precipitation that

comprises the gravity movement of water

in surface channels or depressions. It is a

residual quantity, representing the excess

of precipitation over evapotranspiration

when allowance is made for storage on

and beneath the ground surface.

All water is involved in continuous cyclical

movement according to the hydrologic cycle.

Some of the water vapor in the atmosphere

gives rise to precipitation through complex

processes of condensation and freezing. Not

all precipitation reaches the surface of the

Earth. Some evaporates while falling and, more

importantly, some is intercepted by vegetation

or artificial structures and is then returned to

the atmosphere by subsequent evaporation.

The watershed, or river basin, is the fundamental geographic unit of hydrology. It is also

the fundamental biophysical unit within which

technologies to affect precipitation and runoff

must be assessed. A watershed is a land area

surrounded at its perimeter by highlands that

cause precipitation falling within the watershed’s bounds to flow generally toward its

center to form rivers or streams. In 1970, the

U.S. Water Resources Council divided the

United States into geographic units based on

the watershed, or river basin, for the collection

and organization of hydrologic data (12) (fig. 9).

Water reaching the surface of the watershed

follows one of three courses. First, it may remain on the surface as pools and surface moisture that eventually evaporates back into the

atmosphere. Or it may be stored on the surface

in the form of snow until air temperatures are

high enough to allow melting and runoff. Storage as snow is a common occurrence during

at least a portion of each year in much of the

Western United States.

Second, precipitation reaching the ground

may flow over the surface into depressions and

channels to become surface runoff in the form

of streams and lakes. It then moves by evaporation back into the atmosphere, or by infiltration into the soil and toward the ground water

table, or by continued surface flow back into

the seas.

Third, falling precipitation may infiltrate the

surface and percolate to ground water. As

ground water, it is stored for periods ranging

from days to thousands of years. Ground water

can be removed naturally by upward capillary

movement to the soil surface and plant root

zone, by ground water seepage, or by runout

into surface streams, lakes, and oceans. Some

of it is removed by pumping from wells, in

which case it again arrives at the surface as artificial precipitation and follows one of the

paths described above.

Generally acceptable estimates of the

amounts of water passing annually through the

various phases of the hydrologic cycle for the

Western United States have not been found

in the literature. Based on estimates for the

United States as a whole, however, more than

1,500 million acre-ft of water are added to the

Western United States each year as precipitation and the majority of this is consumed by

evapotranspiration (12). Approximately 500

million acre-ft constitute the measured streamflow from the region (e.g., 4,12) and 50 million

acre-ft of water are added annually to the

ground water reserves of the region.

Runoff is not uniformly distributed throughout the Western United States. Streamflow to

the Pacific Ocean, primarily from the Pacific

Northwest region, is estimated to be over 335

million acre-ft annually, or nearly 70 percent

of the total for the entire region. Almost all of

the remaining surface runoff flows into the

Mississippi River and ultimately into the Gulf

of Mexico. In general, those areas with the low-
N

The conterminous portion of the Western United States has been subdivided into 9 water resource regions, containing

52 subregions as defined by the water Resources Council (WRC) for the Second National Water Assessment. These are

shown below. The water resource regions in the Western United States: (10) the Missouri region, (11) the Arkansas-WhiteRed region, (12) the Texas-Gulf region, (13) the Rio Grande region, (14) the Upper Colorado region, (15) the Lower Colorado

region, (I 6) the Great Basin region, (17) the Pacific Northwest region, and (18) the California region.

The water resources regions consist of either the drainage area of a major river, such as the Missouri region, or the

combined drainage areas of a series of rivers, such as the Texas-Gulf region. The second level of classification, the subregion,

consists either of an area drained by a river closed basin(s), or a group of streams forming a coastal drainage area. Ail

subregion boundaries are hydrologic (i.e., are located along watershed boundaries) except where discontinued at international

boundaries The subregions were reorganized by WRC in 1974 and 1978. They do not correspond to those in use by the

U.S. Geoogical Survey.

SOURCE U S Water Resources Council, The Nation‘s Water Resources 1975-2000 (Washington, DC.: U.S. Government printing Office, 1978)
52 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Photo credit USDA So// Conservation Service

The most important source of renewable surface water supplies in the Western United States is the mountain snowpack.

This photograph of a snowpack in the Teton Range has an average depth of some 5 ft. When Western snowpacks melt

in the spring and summer they supply an estimated 70 to 100 percent (depending on location) of the total annual surface

runoff for all river basins except the Texas-Gulf region

est annual precipitation contribute runoff to

rivers only during sporadic summer thunderstorms. The bulk of the runoff in the region

originates from the melting mountain snowpack each spring and summer. Following

snowmelt, runoff enters the river system of the

region, where it is often stored in surface reservoirs until the period of peak demand in late

summer.

The Components

hydrologic components and also in terms of the

interrelationships among the components.

Precipitation

The primary factor determining the amount

of precipitation that falls over the 17 Western

States appears to be topography (fig. 10). The

four broad north-south zones are generally

more uniform within themselves than are any

two adjacent east-west zones. These general

hydrologic zones are: 1) the mountain ranges

The Western United States has a wide range of the Pacific coast, consisting mainly of the

of hydrologic environments, both in terms of Sierra and Cascade Mountain ranges; 2) the inthe absolute amount of water in the various terior basins; 3) the Rocky Mountains; and fi-
Ch. III—Water Supply and Use in the Western United States ● 5 3

Figure 10. —Major Landforms of the

Western United States

l - -

‘-l. I

The total amount of precipitation and the form in which it

falls (snow or rain) are related more to the major Iandforms

of the region — i.e., mountains or plains—than to any other

factor

SOURCE Off Ice of Technology Assessment

nally 4) the Great Plains, which extend from

the eastern side of the Rocky Mountains to the

western edge of the more humid portions of

the continent, at approximately the 100th meridian, or the Missouri River.

Air masses that carry atmospheric moisture

over the region move generally onto the west

coast of the continent and follow a west-to-east

path. As these air masses cross the Western

portion of the United States, they are forced

upward to cross each of the two major mountain chains in their path. The forced, or orographic, rise produces a band of increased precipitation associated with each of the major

mountain chains. The subsequent descent on

the downwind sides of these chains produces

the two belts of generally deficient rainfall.

— —

Precipitation amounts in the region vary

widely, depending largely on the geographical

location of a particular site with respect to

these mountain chains and on the location of

the major storm tracks (fig. 11). The percentage

of annual precipitation that falls as snow is

highest in the mountain ranges (fig. 12). The

snow/rain ratio is particularly important in

understanding the role played by precipitation

at a particular site. Snow represents a form of

natural storage during months of generally low

water demand and a natural release to surface

runoff at a time approximately coincident with

peak demand. Therefore, it is more important

to agriculture than is an equivalent amount of

rainfall received when demand is low or stored

at high cost.

The greatest amount of precipitation in the

Western United States occurs in the Pacific

Northwest, on the Olympic Peninsula, and on

the west slope of the Cascade Mountains where

amounts total over 100 inches per year. At the

opposite extreme, values of less than 5 inches

per year are recorded in some of the southwestern deserts.

The annual regime of precipitation is highly

variable from one part of the region to another.

As much as half of the annual precipitation

may fall during the growing season in much

of the eastern portion. On the Pacific coast, the

distribution is reversed, and virtually all of the

total annual moisture falls during winter.

Evapotranspiration

Evaporation and transpiration are processes

that return water to the atmosphere. These

processes are controlled by the amount of

energy available to convert liquid water to

vapor and are limited also by the amount of

available water. The term “evapotranspiration’

is used to designate the loss of water from the

soil by evaporation and from plants by transpiration.

Values of evapotranspiration are more difficult to evaluate than those of precipitation because in many areas of the West total evapo-
5.4 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 11.—Average Annual Precipitation of the United States

Precipitation patterns closely reflect a region’s Iandforms, which are a primary factor in determining the amount of

water available for use in any given area,

SOURCE: H. Anderson, M Hoover, and K Reinhart, Forests and Water: Effects of Forest Management on Floods, Sedimentation and Water Suply, USDA Forest Service

General technical report PSW-18, 1976

transpiration is limited only by the available

water supply. Potential evapotranspiration is

the amount of water that would be lost if precipitation were unlimited. Throughout the interior basins, the desert southwest, and much

of the southern portion of the Great Plains, actual evapotranspiration is a small fraction of

potential evapotranspiration.

Actual evapotranspiration is determined in

part by the seasonal distribution of precipitation and in part by air temperature regimes.

If precipitation occurs largely during winter,

as is the case in the mountain ranges of the

Western United States and along the Pacific

coast, much of this precipitation runs off or infiltrates the soil, For most of the region, however, precipitation occurs during the summer,

when evapotranspiration is at a maximum, and

much of it is returned to the atmosphere without affecting other components of the hydrologic cycle.

The timing of precipitation and evapotranspiration is important to agriculture in the

Western United States because of its effect on

available soil water and plant growth. Seasonal

variations in soil water, as determined by the
— .

Ch. Ill—Water Supply and Use in the Western United States ● 5 5

—-.—— —.

Figure 12.—Average Annual Snowfall in the Western United States

section of the country, a result of the increasing length of the winter season with altitude and latitude. This snowfall represents the primary form of natural water storage for the region

SOURCE U S Department of the Interior, Geological Survey, The National Atlas of the United States of America (Washington. D C U S Government Printing Office,

1 970)
56 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

balance existing between precipitation and

evapotranspiration for several selected stations

in the region, are shown in figure 13.

The average potential evapotranspiration in

the Western United States ranges from an estimated low of 15 to 20 inches in the high

mountains of the Pacific Northwest and northern Rocky Mountains to a high of more than

60 inches in small isolated areas in the deserts

of Arizona and southern California (fig. 14). It

is less than 20 inches along the Canadian border and more than 60 inches in southern Texas. Although potential evapotranspiration and

precipitation are independent climatic elements, potential evapotranspiration in arid

regions is greater because of the higher daytime

temperatures resulting from the absence of

clouds and rain. High values in the Colorado

and Gila Deserts and in the lower Rio Grande

Valley are examples. In the arid sections of the

Columbia River Valley between Washington

and Oregon, potential evapotranspiration is

more than 30 inches, whereas it is only about

20 inches at the same latitude in the Eastern

United States.

The variation of potential evapotranspiration

through the year follows a uniform pattern in

most of the region, It is negligible in the winter

months as far south as the Gulf Coastal Plain.

It rises to a maximum in July that ranges from

5 inches along the Canadian border to 7 inches

on the gulf coast. In some mountainous areas

and along portions of the Pacific coast, it does

not reach 5 inches in any month,

Infiltration and Percolation

Precipitation that falls on a surface and that

is not immediately returned to the atmosphere

by evaporation may infiltrate into the surface

soil layers. The amount of that which can infiltrate the surface layers is determined largely by the permeability of those layers (the ability

to transmit water which is governed by the size

and geometry of the spaces within the soil or

rock layers) and the amount of water already

present in those spaces. Infiltration rates are

highest at the beginning of a rainstorm, gradually decreasing with time until some relatively

constant value is reached. Some infiltrated water will be retained near the surface by capillary

forces. Some will move by gravity flow either

toward adjacent stream channels where it will

appear as runoff or, more commonly, downward by percolation to the water table where

it will enter into ground water storage,

All water that exists below the surface of

the Earth in interconnected openings (“interstices”) of soil or rock may be called “subsurface water, ” That part of the subsurface water

in interstices completely saturated with water

is called “ground water. ” The upper surface

of the zone of ground water is known as the

“water table. ” Between the water table and the

surface of the Earth is the “zone of aeration, ’

where the interstices of the soil and rock may

contain some varying amount of water, less

than total saturation. The water table commonly rises and falls as the availability of water at

the surface varies with time (e.g., as a result

of climatic change) or as a result of groundwater extraction practices.

Ground water is not uniformly distributed

throughout the West. The major producing

aquifers are deposits of unconsolidated sands,

gravels, and clays located on preexisting outwash plains or in former lake beds and in the

basalts of the Pacific Northwest. In general, the

thickness of these aquifers ranges from tens of

feet to several thousand feet. Both the amount

of water they produce and the quality of that

water are extremely variable, even from well

to well within the same aquifer. The general

locations of the more important ground-water

resource regions of the Western United States

are shown in figure 15. A detailed discussion

of the individual ground-water resource regions is contained in appendix B.

Surface Runoff

Surface runoff, as rivers or streams, generally

occurs only after the requirements of evapotranspiration and soil- and ground-water recharge have been satisfied. Where the requirements of either, or both, processes are in excess of annual precipitation amounts, no runoff

will take place, Water lost to evapotranspiration is completely lost to runoff. Water that infiltrates into the soil or percolates to ground
Ch. Ill—Water Supply and Use in the Western United States 57—

Figure 13.—The Relationship Between Precipitation and Potential Evapotranspiration

Monthly trends for selected stations in the Western United States show the effects of precipitation and potential

evapotranspiration on soil-water conditions. For all stations, precipitation exceeds evapotranspiration only during the

winter months. During the summer months, periods of soil-water deficits occur and may last up to 6 months.

Centennial, Wyo

San Francisco, Calif.

Santa Fe, N. Mex.

2.3 ins

Manhattan, Kans.

Dalhart, Tex.

Los Angeles, Cal if.

4.0 ins. 18,5 ins.

Helena, Mont.

Grand Junction. Colo.

SOURCE R Thornthwaite, “An Approach Toward a Rational Classification of Climate,’ The Geographical Review, vol 28 (New York American Geographical Society, 1948)

25-160 0 - 5 : QL 3
58 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 14.— Potential Evapotranspiration in the Western United States

The pattern of average annual potential evapotranspiration as calculated by Thornthwaite (1948). This figure is included to ilIustrate a general pattern rather than the actual values for evapotranspiration over the region. Various technologies have been developed to measure total potential evaporation. Actual values will depend on the method of measurement used.

SOURCE: R. Thornthwaite, “An Approach Toward a Rational Classification of Climate,” The Geographical Review, vol. 28 (New York: American Geographical Society, 1948).
Figure 15.—Major

Ch. Ill—Water Supply and Use in the Western United States ● 5 9

Ground Water Resource Regions of the Western United States

SOURCE D Todd. Ground Water Hydrology. 2d ed (New York: John WiIey & Sons, Inc 1980)
60 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— . —— .———-—

water may ultimately appear as surface runoff

at some point distant from that at which it fell

as precipitation, This will be determined by the

amount of transpiration losses, which depletes

soil water, and by the ability of the rock formations at a given location to transmit water.

Surface runoff in the Western United States

is highly variable, both from one river basin to

another and from one time of the year to another. In terms of total volume of annual discharge, the major river system of the region is

the Columbia River, which has a mean annual

flow in excess of 140 million acre-ft and represents nearly 36 percent of the total volume

of surface water available for the entire region.

The river system with the smallest annual disFigure 16.—Average Streamflow

Columbia River.

charge volume is that of the Rio Grande River,

which has an estimated mean annual discharge

between approximately 1.3 million acre-ft/yr

(1.2 million gal/day] (4) and 6.0 million acre-ft/yr

(5.4 million gal/day) (12).

All rivers of the Western United States, except those flowing through the Texas Gulf region, have their headwaters in the mountain

ranges of the region or in Canada (fig. 16). The

period of peak runoff coincides with the period

of spring snowmelt and generally occurs during May or June. There are two exceptions to

this general pattern. First, rivers flowing into

the Pacific Ocean from the west side of the

Sierra and Cascade Mountain ranges in Washington, Oregon, and northern California have

for Major U.S. Rivers, 1941-70

The rivers in the Western States originate in the mountains of Montana, Wyoming, and Colorado, with the exception of

the Red River in northern Texas and the Columbia River, which flows into the United States from the Rocky Mountains in

Canada. One cubic foot per second (cfs or ft3

/s) equals approximately 2 acre-feet per day

SOURCE J Bredehoeft Physical Limitations on Water Resources in the Arid West ‘ paper presented at a conference on Imnpacts of Limited Water for Agriculture

the Arid West, Asliomar, Calif. Sept. 28-Oct. 1, 1982
Ch. I//—Water Supply and Use in the Western United States . 61

— —

a peak discharge in January or February. Second, the lower reaches of the Missouri and

Snake Rivers have a peak flow in March or

April, reflecting the contribution of meltwater

produced by the snow deposits of the plains.

The total amount of runoff contained in

streams during the spring and summer months

varies from over 90 percent of the annual total

for some small streams totally dependent on

the mountain snowpack to less than 15 percent

for streams originating in the Cascade Range,

where the contributions to flow are more uniformly balanced between winter rains and

spring and summer snowmelt. Figure 17 shows

the spatial pattern of the variations in areal

contributions to surface runoff in the Western

United States. These values are the depth of

runoff produced annually and underscore the

importance of the mountainous portions of the

region in determining water supply,

For the Western United States as a whole,

surface runoff estimates vary, depending on

the data source (4,6,12). The range of estimates

is between 515 million and 550 million acreft/yr (460 billion to 490 billion gal/day) for the

amount of surface runoff that passes through

the major river systems of the region.

Variability in the Hydrologic Cycle

Both human-caused and natural variations

in the hydrologic cycle affect the timing and

Figure 17.—The Spatial Pattern of Annual Streamflow

With the exception of the Rocky Mountains and the Cascade-Sierra Mountains, much of the Western United States

averages less than 1 inch of runoff or streamflow annually

sol

Average annual streamflow
62 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

volume of available water in the Western

United States. It is important to recognize that

in the Western United States, very few areas

remain where the hydrologic cycle operates

naturally. Estimates of water availability in any

particular component of the cycle must take

into account human intervention at the specific

site. The impacts of this intervention may vary

from site to site. This is due partly to the particular nature of the human activity and partly to the natural hydrologic variability of the

area. Thus, it is important to understand the

natural variability of Western water resources

as well as the variability when modified by

humans,

Human Intervention

The primary approaches to accommodate

natural variability of Western rivers have been:

1) construction of reservoirs to delay the surface runoff; 2) development of ground water

resources; and 3) in limited cases, importation

of water from adjacent basins with greater natural supplies. It is estimated that in a natural

state the runoff from the 17 Western States

would be approximately 590 million acre-ft/yr

(12). Human modification of the river systems

of the region through the construction of storage reservoirs and water diversions for offstream consumptive uses has reduced natural

runoff by approximately 100 million acre-ft/yr.

Other components of the hydrologic cycle have

also been affected by technological intervention. Human withdrawals from ground water,

estimated to be nearly 70 million acre-ft/yr, affect the amount of recharge required to maintain the natural equilibrium (12).

Natural Variability

For any given watershed, “wet” and “dry”

years are defined with respect to the long-term

average streamflow for that watershed. The

definitions are based on the percentage of time

that given flow volumes occur, as determined

by a statistical analysis of the available

streamflow record. For the Second National

Water Assessment (12), a “dry” year has been

defined in terms of the streamflow that would

occur, as indicated by a statistical analysis of

the data, 20 years out of every century, or 1

year out of 5. The volume of streamflow, as determined in this way, would be much less for

a subregion that has a normally low volume of

streamflow than for one where this volume was

high. Where natural year-to-year variability of

streamflow is low, little difference in the flow

volume will exist between a “dry” year and a

“normal year. ” For those subregions with a

high annual variability, the “dry” year may be

a small fraction of the “normal” year flow

volume.

It is generally recognized that the annual and

seasonal variation in the flow of rivers in the

Western United States is significant, often

varying by as much as 10 times during a year

or during 2 succeeding years. For example,

figure 18 reflects the variability of the Upper

Colorado River, a pattern typical of Western

rivers. Because of such variability, the longterm average annual streamflow volume is not

a particularly useful measure of the amount of

water that will be available for any given year.

Similarly, the monthly volume of flow fluctuates widely, with that occurring during the

spring and summer months often representing

as much as 90 percent of the total annual flow

of many Western rivers (fig. 19). Because of the

extreme variability associated with both the

annual and monthly streamflow volumes,

water-management approaches that are based

on a long-term average annual flow will

generally be unrealistic for shorter time

periods, such as a single year or month during a given year.

In determining the adequacy of existing reservoir storage facilities to meet water demand

for agriculture during a series of dry years, it

is more useful to know the year-to-year fluctuation of flow and the number of years that this

may be expected to drop below an acceptable

level than to know only the average flow for

some period of years. In determining the extent to which a river will meet seasonal needs

of irrigated agriculture, it is more useful to

understand the nature of the seasonal variability of streamflow than to know the annual flow

volume. Most discussions of the adequacy of

water supplies in the Western United States
Ch. Ill—Water Supply and Use in the Western United States . 63

. —— —. .— ——————— ——————

Figure 18.— The Annual Variability of Steamflow Volume, Upper Colorado River, 1920-80

The year-to-year variability of most Western rivers is high, as typified by the Upper Colorado River. Where water IS

a I located on the basis of some long-term mean-flow volume, there wiII be insufficient water to meet that al Iocation during

many years The decreased variability of the Colorado River shown on this fiqure beginning in the mid- 1960’s results from

the construction of dams and reservoirs

1930 1940 1950 1960 1970 1980

SOURCE Off Ice of Technology Assessment. compiled from National Water Data Exchange (NAWDEX), U S Geological Survey, 1983

have been developed in terms of annual mean

values [e. g., 4).

Estimates of future water availability, including that for all types of agriculture, must

be based on some estimates of climatic trends.

Climatic fluctuations affect all components of

food-producing ecosystems, Changes in food

production can be caused by the effects of

weather on pests, pathogens, weeds, and crop

plants and by altering water-supply and wateruse patterns. Western agriculture has developed during a particularly warm period in recent climatic history (7). Climatic records show

that climate has varied in the past, however,

and significant fluctuations have occurred in

recent history,

In addition to the natural variability of climate, there is growing speculation about human-induced climatic change. These include:

1) the decreasing pH (increasing acidity) of

rainfall, which may be caused by emissions

from burning fossil fuel; 2) the gradual increases in the atmospheric fraction of carbon

dioxide (CO2

) and other infrared absorbing

gases, also largely a result of increased burning of fossil fuels; and 3) the associated changes

in water quality, quantity, and, specifically in

the case of the infrared absorbing gases, air

temperature increases.
64 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—.

Figure 19.— Average Monthly Runoff, Clarks Fork, Yellowstone River

Natural seasonal variability in the volume of flow of most Western rivers is large. In come cases, the spring and early

summer snowmelt peak flow of Western rivers represents as much as 90 percent of the annual volume of flow of these

rivers

40

30

20

10

0

Average monthly runoff

Clarks Fork

Yellowstone River

I

SOURCE J Bredehoeft, “Physical Limitations on Water Resources in the And West,” paper presented at a conference on: Impacts of Limited Water for Agriculture

in the Arid West, Asilomar, Calif., Sept 28-Oct 1, 1982

Long-term agricultural planning and policymaking must be undertaken with the knowledge that some climatic change is inevitable.

The geographic extent of any changes in climate will be related to the frequency of the

change. Changes on the order of a few years

to a few decades will be more localized geographically than will those that persist for

decades. To the extent that the ability to predict

climatic trends is limited, so too is the ability

to determine continuing availability of water

for agriculture in the Western United States.

As stated in a National Research Council report

(5), “Our knowledge of mechanisms of climate

change is at least as fragmentary as our data. ”

An improvement in the existing data base, as

discussed in the next section, should be a first

step toward improving the ability to factor

climatic trends into agricultural planning.

Measurement

Water is in continuous movement through

the hydrologic cycle. A variety of measurement

techniques are required to monitor this movement. While all hydrologic processes take place

over the surface area of a region, measurements of elements of the hydrologic cycle such

as evapotranspiration or precipitation are

made at discrete points within that region. In

order to determine the volume of water involved in these transfer processes, it is necessary to combine the individual point measurements into a spatial pattern from which volume

can be estimated.

Some of the problems inherent in all point

measurements may be illustrated by those

associated with determining the amount of rain

that falls at a point, The uncertainties involved
Ch. Ill—Water Supply and Use in the Western United States ● 6 5

—— — —— — — — —

in even this apparently simple measurement Only surface runoff may be measured as an

are illustrated in figure 20. In developing aver- areal value, since all the surface runoff from

age values representative of a particular place a region must pass through a surface-gaging

or time, the selection of the data to be included station. Thus, for surface water, the location

or excluded is critical. selected for the placement of the gaging staFigure 20.— Potential Errors in Water Measurements

Errors can occur in the measurement of any of the components of the hydrologic cycle

and can affect the accuracy of the data.

I I

Gage errors:

Inclination, leaks,

adhesion, evaporation,

I

splash out, condensation

Observer errors

SOURCE R Ward Principles of Hydrology (New York McGraw-HiII 1 975)
66 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

tion is critical. In many cases, the proximity

of a gaging station to the point of use determines the usefulness of the data obtained.

In addition to the uncertainties of point

measurements for estimating spatial volumes,

there are uncertainties in developing time

trends from estimates of selected time periods.

The amount of water in each of the solid, liquid, and vapor phases changes naturally with

time. In order to reduce this continuous variation to terms meaningful for analysis, it is common to present data pertaining to elements of

the hydrologic cycle as averages for selected

time periods. Thus, concepts such as “mean

annual precipitation” or “mean monthly

streamflow” have been introduced to simplify

data manipulation. Ultimately, this simplifying

process has produced concepts such as “the

average precipitation for Arizona” or the

“average runoff of the Upper Colorado River. ”

In both cases, a large amount of spatial and

temporal variation in the natural processes has

been condensed in order to compare the environments of two or more hydrologic areas.

Also, as discussed above, various components of the hydrologic cycle are modified by

human intervention. For example, as water is

stored in reservoirs or removed from the surface or subsurface and applied to some use

such as irrigation, the fundamental natural

relationships are altered. Virtually all the

technologies discussed in this assessment are

designed to modify to some degree the distribution of water within the natural hydrologic

cycle. The degree to which the hydrologic cycle has been modified varies widely among the

river basins of the Western United States. This

human-caused variability further complicates

collecting, interpreting, and developing useful

averages from existing data.

In developing average values, short- and

long-term syntheses are prepared. Short-term

syntheses relate to daily, monthly, or annual

fluctuations and are referred to as “climate”

or as the “hydrologic regime” of a region.

Climate is the average course or condition of

the weather at a place over a period of years,

as exhibited by air temperature, wind velocity, and precipitation. Taken together, these

simple measurements of complex processes of

water and energy transfer estimate the disposition of water among the various phases of the

hydrologic cycle. These short-term syntheses

are important in making decisions concerning

water availability and use from one year to the

next or from one growing season to the next.

Long-term syntheses involve the concept of

climate change over decades, centuries, or

longer. This type of synthesis uses the average

values developed from short-term data collected over a few decades. Long-term change

is identified as the climate slowly becomes wetter or drier, warmer or cooler. An example of

climate change that has been important for recent water planning involves the value for the

average flow of the Colorado River used in the

Colorado River Compact (discussed in ch. V).

Runoff in this river during the period used to

determine an “average” flow for allocating the

waters of the Colorado River was higher than

the average annual flow that now exists. A

change in the climate of that river basin has

gradually decreased the flow of the river below

the value used in the allocation of water between the upper and lower basin States.

Decisions on water availability and use in the

Western United States must reflect uncertainties associated with measurement. To some extent, all measurements of the elements of the

hydrologic cycle are estimates, As concluded

by another OTA assessment, estimates of water

volume or time-trends from point estimates

have varying degrees of reliability (8), The

reliability of these estimates will be determined

by: 1) the ability of an instrument to accurately measure the processes involved; 2) the extent to which the measurement site is representative of the area in which it has been established, and 3) where point-source data (e.g.,

precipitation measurements) are involved, the

number of gages that are combined to develop

the estimate, This reliability is also related to

the length of record and the assumption of no

climate change during the period of record.
Ch. III—Water Supply and Use in the Western United States ● 6 7

—.—.— —

WATER PLANNING, DATA COLLECTION, AND ANALYSES

Evolution of the Federal Role

The Federal Government has been involved

in water-data collection and water-resources

planning and analyses since the formation of

the Nation. It intensified its activities with the

passage of the 1902 Federal Reclamation Act.

More than 20 major national studies or programs have been undertaken since then for the

purpose of defining and guiding Federal activity in this complex and important area (13).

Some of the more publicized programs have

occurred since the 1940’s when a major focus

was the development of multipurpose river

basin plans and the analysis of river basin problems. One reason that the Federal Government

became involved was that river basins and

aquifers (basic water-planning units) almost

always cover parts of more than one State and

require a broad regional geographic perspective. In 1943, the Federal Inter-Agency River

Basin Committee (FIARBC) was established as

a coordinating body for agencies involved with

preparing river basin surveys. After World War

11, FIARBC developed regional committees for

some of the major river basins, including the

Missouri and Columbia basins in the West. In

1959 Congress established a Senate Select

Committee on Water Resources. The work of

this committee was later translated into two

major acts, the Water Resources Research Act

of 1964 (Public Law 88-379) and the Water

Resources Planning Act of 1965 (Public Law

89-90), which has provided the basis for much

recent Federal involvement in water. The

Water Resources Council (WRC) created under

the latter act produced the first National Water

Assessment in 1968,

In the 1970’s, attempts continued to better

define a Federal role in water-resources planning. A National Water Commission, established by an Act of Congress (Public Law

90-515), produced a report to the President and

to Congress in 1973, Water Policies for the

Future. This report outlined several alternative

futures and possible actions for waterresources development to 2020 in light of the

Nation’s water-resource supplies and needs,

WRC produced a second national assessment

in 1978 that compiled data on the Nation’s

water resources to determine the adequacy of

water supplies for meeting anticipated future

needs in the 21 major water-resources regions

of the United States. Then, during the Carter

administration, an intensive review of national

water policy and several water-policy initiatives were begun, including increased attention

to water conservation and environmental quality.

The early 1980’s brought a major reversal in

Federal water involvement from that which

had developed over the past two decades, president Reagan removed Federal sponsorship of

WRC, the river basin commissions (fig, 21), and

the State water research institutes previously

supported through DOI’s Office of Water Research and Technology. This action effectively caused the demise of these institutions except in a few cases where States have attempted to assume full financial responsibility for operations.

These earlier broad-based Federal attempts

to integrate water-resource research, policy,

and planning have not been replaced. The

Reagan administration created a small Office

of Water Policy in DOI in 1982 to serve the

Department Secretary. Then in March 1983,

DOI announced that it would prepare annual

National Water Summary reports in a simplified and condensed form for decisionmakers

as an alternative to previous detailed national

water assessments.

Currently, no additional funds are available

for this activity. All costs for data collection

and analysis are to be absorbed within existing

budgets of the Department and of other agencies that will be expected to volunteer staff and

equipment to respond to data requests. Also,

these summaries will not project future trends.

That function will be a responsibility of the individual States. According to the Department,

this program is in furtherance of the present

administration’s policy “that responsibility for
68 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 21.— River Basin Commissions and Other Regional Water Agencies Abolished in 1981

Klamath River Compact Commission Great Lakes Basin Commission

(Calif,, Oreg,) (N. Y., Ind., Ill., Ohio, Pa., Minn., Wis.)

New England Interstate Water

Pollution Control Commission

(Corm., Maine, Mass. N.H., N. Y., R. I., Vt,)

Tahoe Regional Planning Agency \

I

I

–J

‘(Calif., Nev.) - - ‘

SOURCE: K. C. Flynn, “Loss of River Basin Commissions Forces a Look at Alternatives, ” Journal WPCF, vol. 54, No 1, January 1982, p. 9.

water resources management rests with the

States” (9).

Data Collection and

Analysis Responsibilities

A fundamental barrier to any institutional attempt to assess the nature and magnitude of

potential water-related problems facing Western arid/semiarid lands is the nature and adequacy of the water-resources data base. Basic

hydrologic processes are complex, and the data

required to evaluate water available at a particular point in the process are often unavailable in the form needed.

Responsibilities for water-related data collection, analysis, dissemination of information

based on those data, and planning are scattered

widely among a number of Federal and State

agencies. Most of the regionally useful data

have traditionally been collected by agencies

of the Federal Government (table 11). In recent

years individual States have begun developing

a data collection and interpretation capability

to fulfill local needs.

Among Federal agencies, the lack of a single

or coordinated mechanism for data collection

and analyses has produced a number of data

bases and interpretations with varying degrees

of compatibility. * Beginning in 1973, a national

confederation of water-oriented organizations

was formed to improve access to water data

(10). The resulting program, the National Water

Data Exchange (NAWDEX), became operational in January 1976, with the U.S. Geological

Survey (USGS) having lead-agency responsibility through its Office of Water Data Coordination. NAWDEX can provide data directly or a

listing of those organizations responsible for

the data, together with a description of the

*For an analysis of water models, see the OTA assessment (8).
—.

Ch. III—Water Supply and Use in the Western United States ● 6 9

— —. — —

Table 11.— Federal Water-Data Collection Agenciesa

Government agencies Independent agencies

In-house data programs USDA DOC DOD DOE DOI DOT EPA IBWC NRC TVA

Surface water . . . . . . . . . . . . . . X x x x x x x x – x

Ground water. . . . . . . . . . . . . . . X — x x x x x x – x

Water quality . . . . . . . . . . . . . . . X x x x x x x x –

Water use. . . . . . . . . . . . . . . . . . X x x x x–––– l

Environmental impact . . . . . . . X — x x x x x – – x

Ecology . . . . . . . . . . . . . . . . . . . X – x x x x x – — x

Management effects . . . . . . . . X — x x x x x — – x

Basin studies . . . . . . . . . . . . . . X — — — x x x — — x

Real-time sensing . . . . . . . . . . . X x x – x x — –

Remote sensing . . . . . . . . . . . . X x x – – x x — : x

Data sensing . . . . . . . . . . . . . . . X — x x x — x – —

Instream use . . . . . . . . . . . . . . . X — — — x–––– :

Water rights. . . . . . . . . . . . . . . . X — — — x—––— _

Floods . . . . . . . . . . . . . . . . . . . . — x – – x x–— — x

Energy . . . . . . . . . . . . . . . . . . . . — — — x x–– – x —

Nuclear . . . . . . . . . . . . . . . . . . . . — — — x x – x –

Precipitation quality . . . . . . . . . — — — — x – x—? ;

KEY USDA—U S Department of Agriculture, DOC—Department of Commerce, DOD—Department of Defense; DOE—Department of Energy, DOI—Department of the

Interior, DOT— Department of Transportation, Independent agencies” EPA— Environmental protection Agency; IgwC—international Boundary & Water Commission,

NRC—Nuclear Regulatory Commission, TVA—Tennessee Valley Authority.

aFor the 1981.82 fiscal year, 26 Federal agencies, representing six departments and four Independent agencies, collected water resource data These efforts have pro.-

duced a diffuse data base, confused agency responsibilities for water measurements, and often introduced varying data collection techniques which produce data

Incompatibility

SOURCE U S Department of the Interior, Geological Survey, Office of Water Data Collection. Plans for Water Data Acquisition by Federal Agencies Through Fiscal

Year 1983 (Reston, Va 1982), p 7 -

characteristics of the data. Through NAWDEX,

it is possible to obtain basic data from several

data systems:

●

●

●

●

●

the Water Data Storage and Retrieval

(WATSTORE) System of USGS;

the Storage and Retrieval (STORET) System of EPA;

the Environmental Data and Information

Service (EDIS) of the National Oceanic and

Atmospheric Administration (NOAA);

the Water Resources Scientific Information Center (WRSIC) of USGS; and

various State agencies, such as the Texas

Natural Resources Information System

(TNRIS), the Nebraska Natural Resources

Information System (NNRIS), and the

Utah Division of Water Rights.

NAWDEX is a significant improvement over

the previous method. It was formerly necessary

to obtain the published lists of data from each

responsible agency. However, it is still necessary to analyze any data obtained through the

NAWDEX system, since the system mainly

,

provides data storage and retrieval without extensive analytical capabilities,

For the purposes of this assessment, OTA has

relied heavily on preexisting analyses, rather

than on the data base itself. These analyses,

consisting of reports by the National Water

Commission (6), WRC (12), and USGS (e.g., 4)

provide summaries of many pertinent aspects

of the hydrologic regime of the Western United

States.

There are, however, discrepancies among the

summarized data contained in these reports

(tables 12 and 13). For assessment purposes, it

has been assumed that these discrepancies

have arisen from the nature of the assumptions

made in the analysis of basic data and from the

use of different data bases rather than from

faulty analytical procedures. It has not been

possible to resolve these differences, and they

can only be noted here, In some cases, these

discrepancies are great enough to make it difficult or impossible to reach any firm conclusion about the total availability of water for
70 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

——.— — . —.

Table 12.—Estimates of Average Annual Runoff in the Western United States, 1975

(in billion gallons per day [bgd] and million acre-feet [maf])

Estimates of average annual runoff in the Western United States for 1975, show

a wide range of data. Published estimates for individual regions varied by more than

400 percent. Until discrepancies such as these can be eliminated, it will be difficult

to reach valid decisions on water resource management.

WRC USGS

Region bgd maf bgd maf ‘/o WRC

10

11

12

13

14

15

16

17

18

Missouri . . . . . . . . . . . . . . . . . . . . . 44.1

Arkansas-White-Red . . . . . . . . . . . 62,6

Texas-Gulf . . . . . . . . . . . . . . . . . . . 28.3

Rio Grande . . . . . . . . . . . . . . . . . . 1.2

Upper Colorado . . . . . . . . . . . . . . 10.0

Lower Colorado . . . . . . . . . . . . . . 1.6

Great Basin . . . . . . . . . . . . . . . . . . 2.6

Pacific Northwest. , . . . . . . . . . . . 255.3

California . . . . . . . . . . . . . . . . . . . . 47.4

49.4

70.1

31.7

1.3

11.2

1.8

2.9

285.9

53.1

54.0

73.0

32.0

5.0

13.0

3.2

7.5

210.0

62.0

60.5

81.8

35.8

5.6

14.6

3.6

8.4

235.2

69.4

122

117

113

417

130

200

288

82

131

Regions 10-18 . . . . . . . . . . . . . . . .. ..453.1 507.5 459.7 514.9 101

SOURCES: U.S. Water Resources Council, The Nation’s Water Resources 1975-2000 (Washington, D C. U S Government Printing Office, 1978), vol. 3, table II-6.

C. Murray and E. Reeves, Estimated Use of Water in the United States in 1975, U.S. Geological Survey Circular

765, 1977, p. 18.

Table 13.—Estimates of Total Water Withdrawals in the Western United States, 1975

(in billion gallons per day [bgd] and million acre-feet [maf])

Estimates of total water withdrawals in the Western United States for 1975 were

made by the Water Resources Council and U.S. Geological Survey. A wide range exists in the data, a result largely of data selection criteria and assumptions used in the

interpretation of those data. Until these differences are resolved, it will be difficult to

reach an agreement on the nature of the water problems in the area.

WRC USGS

Region bgd maf bgd maf ‘/o WRC

10 Missouri . . . . . . . . . . . . . . . . . . . . . 38.0 42.6 35.0 39.2 92

11 Arkansas-White-Red . . . . . . . . . . . 13.0 14.6 15.0 16.8 115

12 Texas-Gulf . . . . . . . . . . . . . . . . . . . 26.0 29.1 22.0 24,6 84

13 Rio Grande . . . . . . . . . . . . . . . . . . 6.3 7.1 5.4 6.1 86

14 Upper Colorado . . . . . . . . . . . . . . 6.9 7.7 4.1 4.6 59

15 Lower Colorado . . . . . . . . . . . . . . 8.9 10.0 8.5 9.5 96

16 Great Basin . . . . . . . . . . . . . . . . . . 8.0 9.0 6.9 7.7 86

17 Pacific Northwest. . . . . . . . . . . . . 37,6 42.1 33.0 37.0 88

18 California . . . . . . . . . . . . . . . . . . . . 54.2 60.7 51.0 57.1 94

Regions 10-18 . . . . . . . . . . . . . . . . . . . 198.9 222.9 180.9 202.6 91

SOURCES: US Water Resources Council, The Nation’s Water Resources 1975-2000 (Washington, D C U S Government Print.

ing Office, 1976), Summary, vol 1, p. 25.

C Murray and E Reeves, Estimated Use of Water in the United States in 1975, US Geological Survey Circular

765, 1977, p. 19.

some water resource regions or about the re- dience. The necessity for such an organization

gional usefulness of a given technology de- is doubly important inasmuch as water is an

signed to increase water-use efficiency. extremely dynamic resource. Because of this

dynamism, both the data base and the assumpSome form of coordinating mechanism is es- tions applied to its interpretation must be consential for collecting and synthesizing available tinually tested if both are to remain relevant

data and communicating results to a wide au- to the solution of emerging problems.
Ch. ///—Water Supp/y and Use in the Western United States 71

— —

Relationship Between

Supply and Demand

Depending on the areas, from 70 to 90 percent of the total annual surface runoff and

ground-water recharge in the Western United

States occurs during spring and summer. It is

derived largely from the melting of the mountain snowpack of the region (e.g., 2). The contribution of snowmelt may be as low as 30 percent of the annual total flow in the mountains

of western Washington State, where the precipitation peak occurs as a result of rainfall

during the winter months, to as high as 90 percent along tributaries of the upper Missouri or

Colorado Rivers.

Water is “consumed” when it is withdrawn

and used in such a way that it is no longer

available for additional uses. This means it has

been either evaporated, transpired, incorporated into products or crops, consumed by livestock or humans, or otherwise removed from

the water environment. Water is “used” but not

consumed when it is withdrawn and returned

to a river, as with irrigation return flows,

hydroelectric energy generation, or maintenance of instream flow requirements,

According to USGS data, in 1975, water

withdrawn from surface and ground water

supplies in the Western United States averaged

3,000 gallons per person per day for a population of 50.8 million people. The total withdrawal was approximately 170.7 million acre-ft. A

comparison of total water withdrawal, by State,

is shown in figure 22. Water use in the Western

and Eastern States is compared in table 14.

Figure 22.— Total Off stream Water Withdrawals, by States, 1980

SOU
_ . .

72 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —— —

Table 14.—Per Capita Water Use in the Eastern and Western United States

These figures represent both water withdrawals and consumptive uses.

Contiguous United States

water resources regions

Eastern Western United States (50 States,

(9 regions = (9 regions = District of Columbia,

31 States)a

17 States)a Puerto Rico, and Virgin Islands)

Population, in millions:

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Served by public supplies . . . . . . . . . . . . . . . . .

Self supplied (rural) . . . . . . . . . . . . . . . . . . . . . . .

Per capita water use, In gallons per day:

Off stream use:

Total withdrawals . . . . . . . . . . . . . . . . . . . . . . . .

Public supplies:

All usesc 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Domestic and public uses and Iossesc 

. . . .

Rural domestic used 

. . . . . . . . . . . . . . . . . . . . . .

Irrigation b 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Self-supplied industrial . . . . . . . . . . . . . . . . . . .

Consumptive freshwater useb 

. . . . . . . . . . . . . .

Instream use:

Hydroelectric powerb

. . . . . . . . . . . . . . . . . . . . . .

Total off stream and instream useb 

. . . . . . . .

155.7 69.1 229.6

123.5

32.2

1,600

160

100

73

82

1,300

120

8,900

10,000e

58.1

11.0

2,900

230

150

98

2,000

660

1,200

27,000

30,000e

186.1

43.5

2,000

180

120

79

660

1,100

450

14,000

16,000

qApproximate boundaries

Based on total population.

cBased on population by public supplies

‘Based on rural population.

‘Totals may n ot add due to rounding.

NOTE’ All per capita data calculated from unrounded figures and rounded to two significant figures

SOURCE: W Solley, E Chase, and W. Mann, Estlmate Use of Water in the United States in 1980, U S Geological Survey Circular 1001, 1983

Also according to USGS data, the per capita

consumption of water in the Western United

States averages 1,300 gallons per person per

day, or approximately 145 million acre-ft.

Eighty-five percent of the total withdrawals are

for irrigated agriculture. The amount of this irrigation withdrawal that is consumed ranges

from over 80 percent in the Texas-Gulf Water

Resources Region to slightly more than 30 percent in the Pacific Northwest and Upper Colorado River Water Resources Regions. The

average water consumed by irrigated agriculture for the nine western WRC regions is 56

percent of that withdrawn (4,12). Aspects of

water supply, withdrawal, and consumption in

the nine water-resource regions of the Western

United States are given in table 15.

A variety of problems is encountered in defining the amount of water actually available

for use in the Western United States. The most

obvious one is determining the total volume of

water that passes annually through the hydrologic cycle of the region. A second measure of

water availability, that of determining the quantity of water that is used “consumptively,” and

thus made unavailable for any subsequent uses,

is becoming a less certain indicator of water

availability because, increasingly, nonconsumptive uses such as hydroelectric generation

or instream flow requirements compete with

consumptive uses such as irrigated agriculture.

It is apparent that the same unit of water cannot generate electricity and concurrently be

used for irrigation. Increasingly, decisions

about the timing of storage and release of water

from regional reservoirs will be made in the

context of diverse and often conflicting uses.

Water Supply and Use Patterns

Annual Estimates of Supply

Attempts to estimate a “dependable” supply

for the purposes of water planning and management are partially subjective, involving the

relationship between supply and use at the time

of use. Total annual streamflow is not a useful
Ch. Ill—Water Supply and Use in the Western United States ● 7 3

Table 15.—Water Supply and Use, Including Off-Channel and Hydroelectric Generation, by Region

Water Normal Established Withdrawals Ground water Hydroelectric

resources Area Average runoff a

reservoir dependable all sources’ Consumptio n

c withdrawn ’ generation

region (000 ml 2

) Maf/y r Inches/year storageb (maf) supply a (maf) (maf) (maf) (maf) (maf)

1 0 5 1 5 60. 5 2 . 2 83. 4 33. 6 43. 7 17. 9 13. 4 160, 0

11 2 6 5 81. 8 6 . 0 30. 3 22. 4 26. 9 10. 7 10. 6 70. 0

1 2 1 7 5 35. 8 3 . 9 23. 5 19. 0 19. 0 7 . 3 5 . 7 8 . 7

1 3 1 3 6 5 . 6 0 . 8 7 . 8 3 . 4 5 . 3 2 . 7 2.1 1 . 2

1 4 1 1 0 14. 6 2 . 5 10. 2 14. 6 9 . 5 2 . 6 0 . 2 18. 0

15 1 3 7 3 . 6 0 . 5 61. 3 2 . 2 9 . 7 5 . 5 5 . 0 43. 0

16 1 8 5 8 . 4 1,0 3 . 8 10.1 8 . 4 4 . 4 1.8 6 . 2

1 7 271 235. 0 16. 0 54. 8 78. 4 38.1 13. 4 9 . 2 1,700, 0

1 8 1 2 0 69. 4 9 . 0 40. 0 31. 3 60. 5 28. 0 23. 5 83. 0

Tota l 1,91 4 514. 9 4 , 7 315. 0 215. 0 221. 1 97. 5 71. 6 2.090. 1

Percent o f

conterminou s

U s . 630/o 380/o 560/o 70 ”/0 37 ”/0 44 ”/0 57 ”/0 73 ”/0 560/o

NOTE Partial figures may not add because of independent rounding.

aC. Murray and E Reeves Estimated Use of Water in the United States in 1975, U S Geological Survey Circular 765, 1975

bUS Water Resources Council, The Nation's Water Resources 1975-2000 (Washington, DC U.S Government Printing Office, 1978), vol 2, pt. IV, 1978, p 13

CW. Solley, E Chase, and W Mann, Estimated Use of Water in the United States in 1980, U S Geological Survey Circular 1001, 1983

indicator of water availability for most uses

because a considerable amount of seasonal and

year-to-year variation exists in the volume of

flow of the rivers of the Western United States.

Water supply at any point is a result of a complex interaction between withdrawal activities

and return flows all along the system, involving some consumptive uses and some instream,

nonconsumptive uses. Moreover, these use patterns are subject to change as the needs or

desires of society change.

Analyses of the adequacy of water supplies

are commonly based on the annual amounts

of consumptive water use and streamflow.

USGS has developed estimates of dependable

annual supply for the water-resource regions

(14), based on a statistical analysis of streamflow records and an evaluation of the degree

to which reservoir storage assists streamflow

in maintaining a satisfactory available supply.

These estimates do not relate specifically to the

needs of irrigated agriculture because they do

not reflect the relationship between supply and

use patterns during summer when demand for

irrigation water is at a maximum. They do,

however, serve as a useful first approximation

of water availability in the West.

According to the USGS statistical analysis of

streamflow and storage, the Missouri and Arkansas-White-Red regions have moderately

large water supplies and favorable supply-to25-160 0 - 6 : QL 3

demand relationships. In the Texas-Gulf region, withdrawals are greater than the estimated dependable supply and have exceeded

the flow in 90 years out of 100, and excess demand is made up largely from ground water

and water reuse, Consumption of water in the

Rio Grande region is greater than dependable

supply, while in the Upper Colorado region,

supply exceeds demand. Both water withdrawals and consumption in the Lower Colorado region exceed the supply originating in that area.

Excess demand is met by inflow of water from

the Upper Colorado region, importation of surface water, repeated withdrawals of water, and

ground water “mining.” Large ground water

withdrawals are characteristic of the TexasGulf, Rio Grande, Arkansas-White-Red, Lower

Colorado, and California regions,

A slightly different approach to estimate

water supply and demand has been used by

another USGS scientist who defines a “relative

water depletion” index as the total consumptive use plus any water exported from each

basin, divided by the total supply (1). Ground

water mining was excluded from this USGS

calculation,

Bredehoeft found that for:

1. most of the lower Colorado River basin,

southern California, and most of Nevada,

depletion exceeds 100 percent of the annual surface supply;
74 . Water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

2. south-central California, including the San

Joaquin and Owens Valleys, depletion exceeds 75 percent of the annual surface supply;

3. the High Plains of Colorado and west Texas, depletion exceeds 75 percent of annual surface supplies; and

4. much of New Mexico, depletion exceeds

75 percent of annual surface supplies.

A third comparison of water supply and use

in the Western United States is contained in

the Second National Water Assessment (12).

This assessment presents both annual aggregate values of streamflow, total water use (including instream flow requirements), offstream

consumption, and ground water mining for the

52 water-resources subregions of the West as

well as monthly values for each. In the Second

National Assessment, “use” is defined as the

total of all offstream consumptive uses plus

evaporation losses (from ponds and reservoirs)

and net imports of water. “Supply” is defined

as the streamflow volume that would occur at

the outflow point of each subregion if consumption were eliminated, ground water overdrafting were discontinued, and current water

transfer and reservoir practices were continued.

Based on the Second National Water Assessment data for average year conditions, total

water use exceeds streamflow in 28 subregions,

which account for about 66 percent of the

West’s irrigated land (fig. 23). In most of the

other 24 subregions, there is little difference

between streamflow and total water use. Total

use is less than 75 percent of streamflow in one

subregion, northern California, where there is

limited agricultural potential,

In a year of below-average streamflow, the

imbalance between supplies and estimated

Figure 23.—Water Resource Subregions Where Total Water Use Exceeds Streamflows in an Average Year
Ch. III—Water Supply and Use in the Western United States ● 7 5

total water use is more intense and widespread.

Shortfalls are more likely not only because supplies are reduced but also because demand may

be higher, especially for irrigation to compensate for reduced precipitation. In a dry year,

total water use exceeds streamflow in 48 of the

52 subregions. Four of the exceptions are in

the Pacific Northwest region, and the other is

in the northernmost subregion of the California region. In eight of the subregions, use is

more than twice the dry-year streamflow.

Monthly Estimates of Supply

The use of annual aggregates to determine

the water-supply/use patterns of the Western

United States often obscures the seasonal nature of many of the shortages that characterize

the area. A more reasonable indicator of adequacy would relate water supplies to water

needs of humans, animals, and plants during

periods of maximum need. Currently, the

shortest period for which data are readily

available is 1 month. While this is longer than

most living organisms can survive without

water, it approximates more closely a realistic

indicator of water-supply adequacy. An inspection of the Second National Water Assessment

data suggests that there are at least three major water-supply/use patterns in the Western

United States. These are subregions where:

1) streamflow exceeds offstream uses during

every month of the year; 2) streamflow exceeds

offstream uses during summer months only,

when irrigation withdrawals reach their peak;

and 3) streamflow is exceeded by offstream

uses during every month of the year.

The Second National Water Assessment

found that in 26 of the 52 water-resources

subregions of the Western United States, offstream water use exceeded 90 percent of the

average monthly supply during at least 1 month

each summer (table 16). These subregions are

generally located in the areas also identified

by USGS sources (1,4) as experiencing watersupply problems. Those areas experiencing at

least 1 month of a water-supply deficit during

each summer are southern California; the Great

Basin; portions of Arizona, New Mexico, Colorado, Nebraska, Kansas, Texas; and the Snake

River Plain in southern Idaho.

Consumptive Uses of Surface Water

Consumptive uses of water account for more

than the amount being renewed on an annual

basis in approximately 40 percent of the waterresources subregions of the Western United

States during at least some portion of each

year, For much of the Western United States,

August is the month of maximum offstream

consumptive use. In August, generally, streamflow volumes have diminished significantly

from the peak flows of springtime snowmelt.

Based on August values of offstream consumption and total streamflow taken from the Second National Water Assessment (12), figure 24

shows that for all of the water-resources

regions of the West (excluding the Pacific

Northwest), consumption of water is estimated

to be about 90 percent of total streamflow during the month of August and goes as high as

395 percent of streamflow in the Brazes River

subregion in Texas (12). * Water consumption

of many of the subregions of the West actually exceeds 90 percent of streamflow during

more than 1 month of each year (see table 16).

This suggests that there is currently no excess

surface water during August in the Western

United States, since even in the Pacific Northwest water that is not used off stream is required for instream hydroelectric generation.

In some areas, no excess surface water exists

during other months as well. A variable percentage of this water consumption is based on

reuse of surface waters and ground water withdrawals depending on the water-resources region. If it is assumed that ground water

withdrawal is not sustainable because of “mining” and rising energy costs, current patterns

of Western water consumption and use are

probably not sustainable.

The monthly patterns of water supply and

offstream use for several selected subregions

“Total streamflow is defined as a “computed flow that includes

effects of consumption, ~ater transfers and evaporation from

manmade reser~oirs, but not ground [i. ater overdraft.
76 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 16.—Western Water Resource Subregions Where Off stream

Use Exceeds Total Streamflow

Region Subregion Months during which off stream use

number number Name exceeds 90°/0 of total streamflow

10

11

12

13

14

15

16

17

01

02

03

04

05

06

07

08

09

10

11

01

02

03

04

05

06

07

01

02

03

04

05

01

02

03

04

05

01

02

03

01

02

03

01

02

03

04

01

02

03

04

05

06

07

18

01

02

03

04

05

06

07

MISSOURI:

Missouri-Milk-Saskatchewan . . —

Missouri-Marias . . . . . . . . . . . . . —

Missouri-Musselshell . . . . . . . . . —

Yellowstone . . . . . . . . . . . . . . . . —

Western Dakotas . . . . . . . . . . . . —

Eastern Dakotas . . . . . . . . . . . . . —

North and South Platte . . . . . . . June-September

Niobrara-Platte-Loup . . . . . . . . .July-September

Middle Missouri . . . . . . . . . . . . . —

Kansas . . . . . . . . . . . . . . . . . . . . . July-August

Lower Missouri . . . . . . . . . . . . . . —

ARKANSAS-WHITE-RED:

Upper White . . . . . . . . . . . . . . . . —

Upper Arkansas . . . . . . . . . . . . .June-July

Arkansas-Cimmaron . . . . . . . . . . July-August

Lower Arkansas . . . . . . . . . . . . . August

Canadian . . . . . . . . . . . . . . . . . . . July-September

Red-Washita . . . . . . . . . . . . . . . . July-September

Red-Sulphur . . . . . . . . . . . . . . . . —

TEXAS-GULF:

Sabine-Neches . . . . . . . . . . . . . . —

Trinity-Galveston Bay . . . . . . . . —

Brazes . . . . . . . . . . . . . . . . . . . . . July-September

Colorado (Texas) . . . . . . . . . . . .June-September

Nueces-Texas Coastal . . . . . . . . —

RIO GRANDE:

Rio Grande Headwaters . . . . . . July-August

Middle Rio Grande. . . . . . . . . . . June-October

Rio Grande-Pecos . . . . . . . . . . . March-September

Upper Pecos . . . . . . . . . . . . . . . . April-September

Lower Rio Grande . . . . . . . . . . . March-August

UPPER COLORADO:

Green-White-Yampa . . . . . . . . . . —

Colorado-Gunnison . . . . . . . . . . —

Colorado-San Juan. . . . . . . . . . . —

LOWER COLORADO:

Little Colorado . . . . . . . . . . . . . . —

Lower Colorado Main Stem . . . March-October

Gila. . . . . . . . . . . . . . . . . . . . . . . . January-December

GREAT BASIN:

Bear-Great Salt Lake . . . . . . . . . July-August

Sevier Lake . . . . . . . . . . . . . . . . . June-September

Humboldt-Tonopah Desert . . . . February-December

Central Lahontan . . . . . . . . . . . . August

COLUMBIA:

Clark Fork-Kootenai . . . . . . . . . . —

Upper/Middle Columbia. . . . . . . —

Upper/Central Snake . . . . . . . . . —

Lower Snake . . . . . . . . . . . . . . . . —

Coast-Lower Columbia . . . . . . . —

Puget Sound . . . . . . . . . . . . . . . . —

Oregon Closed Basin . . . . . . . . —

CALIFORNIA:

Klamath-North Coastal . . . . . . . —

Sacramento-Lahontan . . . . . . . . —

San Joaquin-Tulare . . . . . . . . . .June-October

San Francisco Bay. . . . . . . . . . . July-August

Central California Coast . . . . . . June-September

Southern California . . . . . . . . . . April-November

Lahontan-South . . . . . . . . . . . . . April, July-September

SOURCE’ U S Water Resources Council, The Nation’s Water Resources 1975-2000 (Washington, D.C U S Government Printing Office, 1978), vol 3, app Ill, table III-5.
Ch. Ill—Water Supply and Use in the Western United States ● 7 7

. — . —

Figure 24.—Ratio of Off stream Consumptive Use to Streamflow During August

SOURCE U S Water Resources Council The Nation‘s Water Resources 1975-2000 (Washington, D.C. U.S. Government Printing Office 1978)

in the Western United States are shown in

figure 25A, B, and C. These rivers are, respectively:

1.

2.

3.

the Yellowstone, a tributary to the Missouri, which has its headwaters in the

northern Rocky Mountains;

the North and South Platte Rivers, which

originate in the Colorado Rocky Mountains and flow eastward through Nebraska

to enter the Missouri River; and

the Gila River, which drains the southwestern portion of Arizona and includes

the metropolitan areas of Tucson and

Phoenix within its watershed.

The monthly supply/demand relationships

for the Yellowstone River in southwestern

Montana are typical of many of the rivers of

the Pacific Northwest and northern Rocky

Mountains, where water supplies normally exceed withdrawals during all months of the

year. For the North and South Platte Rivers in

Colorado, Wyoming, and Nebraska, supply exceeds withdrawal only during the winter

months. During the irrigation season, from

April through August, offstream demand exceeds the supply available from these rivers

during each month. The deficit is made up by

pumping ground water. This pattern is typical

for a majority of the water-resources subregions of the Western United States. The most

extreme imbalance between supply and offstream demand is represented by the Gila

River, which is characteristic of those in the

Southwestern tier of States. Here, offstremn demand exceeds supply during every month of

the year, a situation made possible only by the

reuse of surface water supplies and by extensive ground water “mining, ”
78 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 25.— Monthly Relationship Between Water Supply and Use for Three Western Rivers

1004

Month

A. The Yellowstone River, a tr[butary to the Missouri

River. This pattern is typical of many In the northwestern

portion of the Western United States.

Month

B. The North and South Platte Rivers, tributaries to the

Missouri River in the central portion of the Western

United States. Use of water in this subregion exceeds

supply during a portion of each year. This deficit is made

up by pumping ground water.

C. The Gila River in Arizona. Water use exceeds the

renewable supply during every month of the year in this

river basin. This is made possible only by the extensive

mining of ground water.

SOURCE Office of Technology Assessment, 1982, from U.S Water Resources Council, 1978
Ch. I/l—Water Supply and Use in the Western United States ● 7 9

Offstream demand in excess of surface water

supply in the southwestern United States has

become a difficult social and economic problem. An extensive social infrastructure has

developed in that region based largely on investments that depend on a reliable water supply. In these regions, surface supplies often do

not meet demands and ground water must be

tapped, From a hydrologic point of view,

ground water use in excess of ground-water

recharge cannot be sustained into the future,

either because of declining volumes of water

in the aquifers of the region or increasing

pumping costs to extract the water. These factors are contributing to shifts in water-use patterns in the Southwestern United States. (See

app. B for further graphics on variability

among the water resource regions in spatial

and temporal availability of water and in the

use of that water.)

Nonconsumptive Uses of Surface Water

A number of nonconsumptive instream uses

are as important as consumptive uses but are

not often generally considered in determining

the supply/use relationship for an area. These

are instream requirements for habitat maintenance and waste assimilation, hydroelectric

generation, recreation, and the maintenance of

commercial fisheries.

Instream uses, “ . . . that amount of water

flowing through a natural stream channel

needed to sustain the instream values at an

acceptable level” (12), are particularly difficult

to define or quantify. The first attempt to accomplish this was made by the Second National Water Assessment, largely based on minimum streamflow levels required for maintenance of fish and wildlife populations and for

navigation, where applicable.

An example of the economic and social

desirability of maintaining sufficient instream

flow for the support of fish habitat involves the

salmon fishing industry of the Pacific States

of Washington, Oregon, and northern California. The anadromous (primarily salmon) fish

runs of the rivers draining into the sea have

national as well as regional importance because they support a commercial fishery, an

extensive sports fishery, and an Indian fishery.

Damage to this fishery, either by a diminution

of instream flows or by undesirable water-quality changes, will have both serious economic

and social effects.

Other instream uses also exist that have a

direct impact on human activity. An important

instream flow use involves waste assimilation

and dilution. It is common practice to discharge municipal and industrial wastes into

streams with less than complete, or tertiary,

treatment (3). Approximately 50 percent of the

water used in irrigation returns to the river

degraded in quality. Without some minimum

level of streamflow, the water quality of return

flows will become, in effect, the water quality

of the stream. While this will have an effect on

fish and wildlife, it also will mean that the

water will require extensive and expensive

treatment before being suitable for human domestic use.

A third instream use in a number of the

water-resources regions of the Western United

States involves hydroelectric generation, This

use requires that water be “spilled” from a

reservoir. If this spillage is to be consistent with

the energy demands of the region supplied,

reservoir water levels cannot be allowed to fall

below some minimum level. If an optimum

reservoir level is to be maintained, the spillage

must be approximately equal to the amount of

water flowing into the upstream end of the

reservoir. In the case of the Pacific Northwest

Water Resources Region, for example, present

patterns of hydroelectric generation require

that a monthly average of 140 million acre-ft

of water (1.7 billion acre-ft/yr, or more than 12

times the annual flow of the Columbia River)

be discharged from the reservoirs of the region

to generate the energy being produced there,

Without cumulative inflows to these reservoirs

of 140 million acre-ft/month, hydroelectric

generation must decrease. Thus, this instream

use requires a certain volume of water with

relatively little room for equivocation. Other

uses such as irrigated agriculture, which might

require reservoir water, would be detrimental
80 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

to the hydroelectric use at the point that agricultural demands cause reservoir drawdown

and decreased power generation.

Fourth, outdoor recreation activities, while

somewhat more difficult to quantify, are important instream uses. According to the Second

National Water Assessment, in 1975 there were

592 million water-related outdoor recreation

activity “occasions” * in the 17 Western States.

On a per-capita basis, this is 11.8 occasions per

capita in those States compared with a per

capita average of 8.4 occasions in the Eastern

United States. Most of the water-related recreational activities in the water-short Western

United States center on reservoirs and the freeflowing streams of the region. In both cases,

some minimum level of instream flow is required to maintain a reservoir pool level

suitable for recreational purposes. A minimum

instream flow is necessary specifically to main-

* Participation by a person 12 years or older in a specific activity without regard to the duration of the activity.

tain flows during late summer in unregulated

streams and to maintain recreational activities

below dams on regulated streams.

There are no simple measures of instream

flow requirements. To a certain extent, these

must reflect the current level of development

within a given river basin or along a given

stream reach. Water use has already exceeded

average annual streamflow in the Southwestern and Great Plains subregions of the Western United States. For these areas, adding

another use in the form of instream flow requirements is largely academic.

The issue of instream uses and their priority was raised but not resolved in the Second

National Water Assessment. An acceptable definition and quantification of these important

uses should be of the highest priority for economic, social, and environmental reasons, Because these uses have national as well as regional and local significance, this area needs

national as well as regional and local attention

(see also ch. V).

FUTURE ENERGY DEMANDS FOR WESTERN WATER

Water availability is commonly noted as one

of the key factors for the successful development of Western energy resources. Some areas

of the northern Great Plains and the Rocky

Mountain region already are experiencing economic activity as the result of energy development. Surface waters from both the Upper Colorado River Basin and Upper Missouri River

Basin, as well as ground waters in these areas,

have been described in a number of studies for

purposes of water availability for Western energy development. *

Water requirements of energy facilities vary

considerably. For example, coal-fired electric

*See previous OTA reports on: Increased Automobile Fuel Efficiency and Synthetic Fuels: Alternatives for Reducing Oil Imports, OTA-E-186, September 1982; An Assessment of Oil Shale

Technologies, OTA-M-118, June 1980; 7’he Direct Use of Coal.’

Prospects and Problems of Production and Combustion, OTAE-86, April 1979; and A Technology Assessment of Coal Slurry

Pipelines, OTA-E-60, March 1978. Also see Science and Public

Policy Program, University of Oklahoma, Energy From the West:

A Technology Assessment of Western Energy Resource Development, 1981, Univemity of Oklahoma Press.

power generation requires more water than

synthetic fuel technologies and more water

than slurry pipelines to produce an equivalent

amount of energy. High-Btu coal gasification

consumes more water than either coal liquefaction or in situ oil shale production, but less than

some oil-shale conversion methods. Water requirements for shipping coal by slurry pipelines are less than for some conversion facilities.

projections of actual water demand from

Western energy development are difficult and

depend on numerous assumptions about Western law, needs of existing users, economic

value of the water to be used, the specific site

and time of development, and the technology

used. Studies on individual energy resources

have concluded that sufficient quantities of

suitable water may be physically available or

could legally be made available for certain

kinds of energy development. The quality of

water required for some energy uses may be

lower than that required for agriculture.
Ch. III—Water Supply and Use in the Western United States ● 8 1

— -. .-

No definitive estimate of the cumulative effects of Western energy development for agriculture is available, however. The difficulty

with providing such an estimate is due, in part,

to complex and dynamic legal, institutional,

political, and economic issues involved. Moreover, data on water availability, current uses,

and future demands are incomplete. The impacts of water demand for energy hinge on the

quality of water required and future local,

State, and Federal roles in programs to make

water available for energy development. International activities also will influence the

Western energy industry. The energy-specific

studies generally recognize that on a sitespecific basis, some Western agricultural areas

could experience significant impacts from increased water use for energy.

CONCLUSIONS

Both the spatial and temporal availability of

water for agricultural uses in the Western

United States are related to variations in the

components of the hydrologic cycle. It should

be recognized that the use of a technology to

produce a change in any single component of

the hydrologic cycle to create additional water

or water savings will inevitably affect other

components of the cycle. A detailed analysis

of the existing hydrologic regime at the site of

technological modification will help to determine the extent to which that modification will

affect the desired change (e. g., in increased surface runoff, decreased evapotranspiration, and

increased soil-water storage). It will also help

to define possible adverse impacts on other

components of the cycle.

Evaluating the potential of a given technology for either producing additional water or

conserving supplies will be difficult unless the

quantities of water now involved are defined

more accurately. Both the reliability and availability of water-resources data present problems for site-specific hydrologic analysis. Estimates of annual streamflow volume now vary

by as much as several hundred percent, depending on the river basin and the source of

the estimate. Additional cooperation and coordination among the involved Federal and State

agencies would help to resolve water-data problems and discrepancies. Consideration should

be given to using a lead agency concept for

various data-reIated activities.

It is inevitable that both short- and long-term

fluctuations in climate affecting water availability in the Western United States will

continue in the future. Short-term variations

in water supply lasting a single season or year

have traditionally been a factor in planning and

management of the water resources of the region. Changes in the water supply associated

with long-term changes in the climate are Iess

commonly considered in either planning or

management. The past several decades have

been particularly favorable for agricultural

development. It must be assumed that present

levels of agricultural production are at least

partly the result of this, Short-term fluctuations

in water supply can be accommodated in management and planning schemes by a statistical

analysis of trends in the recent past, However,

because there is no reliable method for predicting the nature of long-term trends, water use

and planning over the long-term should tend

toward conservative estimates of future availability.

The most important source of renewable surface water supplies in the Western United

States is the mountain snowpack. This snowpack accumulates during the winter months in

both the mountains bordering the Pacific

Ocean and the Rocky Mountains in the interior. When it melts in the spring and summer

months, it supplies an estimated 70 to 100 percent (depending on location) of the total annual

surface runoff for all river basins except the

Texas-Gulf region. Traditionally, the approach

to the study of water resources in the Western

United States has been one that emphasized

problems related to meeting demand rather

than those associated with the sources of

supply,

Relatively little research attention has been

given to the snowpack, either in terms of the

spatial and temporal variations of volume of

water stored each year or the rate at which sur-
82 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

face runoff is produced during the melt seasons. Technologies such as weather modification and streamflow forecasting to improve

reservoir management would benefit considerably from an increased understanding of the

snowpack as the dominant source of the renewable surface water supplies. The snow

survey program of the USDA Soil Conservation Service has produced a valuable data base

that would greatly facilitate this research.

Based on the available estimates of water

supply and use, almost half of the Western

United States is experiencing water-supply

problems in relation to demand. In much of the

Southwest and southern High Plains, the total

available surface supply is used in some way

1.

2,

3,

4.

5.

6.

7.

CHAPTER Ill

Bredehoeft, J. “Physical Limitations on Water

Resources in the Arid West, ” paper presented

at a conference: lrnpacts of Limited Water for

Agriculture in the Arid West, Asilomar, Calif.,

Sept. 28-Oct. 1, 1982, Department of Land, Air,

and Water Resources, University of California,

Davis.

Castruccio, P., Loats, H., Lloyd, D., and Newman, P,, Apphcatkms Systems Verification and

Transfer Project, Volume VII: Cost/Benefit

Analysis for the ASVT on Operational Applications of Satelljte Snow-Cover Observations, Nati~nal Aeronautics and Space Administration

(NASA) Technical Paper 1828, 1981.

Gordon, Larry, OTA Advisory Panel Member,

personal communication, March 1983.

Murray, C., and Reeves, E. Estimated Use of

Water in the United States in 1975, U.S. Geological Survey Circular 765, 1977.

National Research Council, National Academy

of Sciences, Understanding Climatic Change:

A Program for Action, U.S. Committee for the

Global Atmospheric Research Program, National Research Council, Washington, D. C., 1975.

National Water Commission, Water Policies for

the Future, Final Report to the Congress of the

United States by the National Water Commission (Port Washington, N. Y.: Water Information

Center, Inc., 1973).

Shaw, R, “Climate Change and the Future of

American Agriculture,” The Future of American Agriculture as a Strategic Resource, The

Conservation Foundation, 1980.

annually, and ground water is being withdrawn faster than its recharge rate in order to

sustain the levels of use that have developed.

Ground water mining can only be considered

a short-term solution to water-supply problems,

since diminishing reserves and increasing

energy costs may gradually make the pumping

of ground water prohibitively expensive,

Where water supply is not entirely consumed,

competing nonconsumptive uses, such as instream flow requirements or hydroelectric

generation, are increasingly creating scheduling conflicts for offstream uses. Water-quality

problems may prove to be an even more critical

factor affecting patterns of future Western

water use.

REFERENCES

8. U.S. Congress, Office of Technology Assess9!

100

11.

12,

13,

14.

-.

ment, Use-of Models for Water Resources Management, Planning, and Policy, OTA-O-159, August 1982.

U.S. Department of the Interior, “Watt Announces New System for Summarizing the Nation’s Water Resources, ” Department of the

Interior news release, Mar. 10, 1983.

U.S. Department of the Interior, Geological

Survey, “NAWDEX: A Key to Finding Water

Data,” Informational Brochure, National Water

Data Exchange, undated,

U.S. Department of the Interior, Geological

Survey, Office of Water Data Coordination,

“Plans for Water Data Acquisition by Federal

Agencies Through Fiscal Year 1983, ” April

1982.

U.S. Water Resources Council, The Nation

Water Resources 1975-2000, vol. 1-4 (Washington, D. C.: U.S. Government Printing Office,

1978).

Viessman, Warren, Jr., “Coordination of Fecieral Water Resource Policies and Programs, ”

Report No. 78-227 ENR (Washington, D. C.:

Congressional Research Service, Library of

Congress, Nov. 22, 1978).

Woodward, D,, Availability of Water in the

United States With Special Reference to Industrial Needs by 1980 (Washington, D. C., Armed

Forces Industrial College, 1957). In: Murray and

Reeves, 1977.
"Pollutions”

Water Quality
Page

Water Quality in Arid and Semiarid Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

The Effects of Water Quality on Agriculture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Domestic Use on Ranches and Farms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Livestock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Irrigation: Salts and Ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Irrigation With Wastewater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Heat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Radioactive Substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

The Effects of Agriculture on Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Suspended Sediments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Plant Nutrients and Fertilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Dissolved Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Animal and Other Organic Wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Agricultural Chemicals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Water-Quality Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. ... ... ... .$... ... ... .$..... 102

Chapter IV References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

List of Tables

Table No. Page

17. Summary of Classifications of Irrigation Waters. . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

18, Trace Element Tolerances for Irrigation Waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

19. Population Equivalent of the Fecal Production by Animals

in Terms of Biochemical Oxygen Demand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

20. S elected Infections and Infestations Shared by Humans

and Vertebrate Animals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

21. Organochlorine Insecticides in Illinois From Cow’s Milk . . . . . . . . . . . . . . . . . . . . 97

22. Pesticides in Human Milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

23. Pesticides in Diet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... .. t...... 98

24. Categories of Known or Suspected Organic Chemical Carcinogens

Found in Drinking Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

25. Organic Pesticides and Other Organic Contaminants in Drinking Water,

Concentration, Toxicity, ADI, and Suggested No-Adverse-Effect Levels . . . . . . . 100

26. Organic Pesticides and Other Organic Contaminants Found

in Drinking Water, With Insufficient Data on Chronic

Toxicity to Calculate an Acceptable Daily Intake . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Chapter IV

Water Quality

Water-quality deterioration in the Western

United States would have significant impacts

on water use, Although agriculture is the primary user of water in the region, water-quality

problems are associated with all uses,

This chapter presents an overview of two

aspects of water quality of the Western United

States: 1) the impacts that water quality has on

agriculture and 2) the impacts that agriculture

has on water quality. While the chapter is not

an exhaustive consideration of all the waterquality implications for water supply and use

in the Western United States, it does illustrate

the broad nature of the problem and some of

the more salient public health implications.

The discussions of this problem in the

literature, on which this chapter is based, are

fragmentary, and it is apparent that legitimate

differences of opinion exist concerning the

seriousness of the problem. Water planners and

managers must be aware of these different interpretations but must also understand that, at

least locally, water pollutants and their associated health problems have been detected

in the region. With the increasing water usage

indicated by present trends, these pollution and

health problems can only worsen without concerted action on the local, State, and Federal

level.

WATER QUALITY IN ARID AND SEMIARID REGIONS

Water quality defines the physical, chemical,

and biological attributes that affect the suitability of water for agricultural, industrial, and domestic uses as well as for recreation and wildlife habitat. These attributes are closely linked

to the physical availability of water, the extent

to which the available resources are used, and

the nature of the water-quality changes that use

produces. Water quality is determined both by

the nature of the pollutant and the concentration of that pollutant in the water.

No water problems are unique to the arid and

semiarid portions of the Western United States.

The more limited amount of water available in

this environment, however, has the potential

to increase the severity of any that do exist. For

example, arid and semiarid environments are

commonly characterized by high natural levels

of salinity in the soil owing to the imbalance

between precipitation and evaporation which

decreases natural leaching, The sporadic runoff that characterizes these environments will

often contain high concentrations of both suspended and dissolved solids which are added

to the perennial river system. It is estimated,

for example, that natural sources account for

about two-thirds of the total annual dissolved

salt carried by the Colorado River. For portions

of this river, this represents values that may exceed 1,500 parts per million (ppm) total dissolved solids, or three times the recommended

level for municipal drinking water.

The fact that there is less total water available

in arid and semiarid environments means that

each unit of water must be more fully used, resulting in the development of patterns of reuse

in which each unit of water must be used consecutively as it moves through a river system.

Thus, water may be withdrawn from the river

and partially consumed by irrigation; the return flow may be stored in a reservoir where

it will ultimately be used to generate hydroelectric energy; and then, following release, the

water may be withdrawn by a municipality for

85
86 l Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— —

domestic consumption. The return flows from

each of these sequential uses have increasing

levels of pollutants and may ultimately have little reuse potential without significant treatment (35). While continued reuse of streamflows for irrigation without treatment has become a necessity in many of the water-short

areas of the Western United States, the gradual

buildup of salts and agricultural chemicals in

the soils and in the water itself could ultimately

prove to be more detrimental to agriculture and

other water users than will increasing water

shortages.

Traditionally, the streams, lakes, rivers, and

ground water of the Western United States

have seemed a convenient and seemingly inexpensive and inexhaustible dumping area for

human and animal wastes and residues from

industry and municipalities. Many waterquality problems have been identified in the

Western United States; most on a site-specific

basis, depending on the type of pollutant and

the nature of the ground and surface water

system into which it is introduced. Experts

disagree about the nature or extent of existing

water-quality problems and about related public health aspects. Based on available evidence,

however, concern is justified.

The kinds and amounts of impurities in

water depend on a number of environmental

factors, such as source of water and physiogeographic characteristics of the environment

through which the water moves, and on the effects of human activity on water quality. In

practice, it is difficult to separate water-quality

from water-quantity problems in the Western

United States. The development and use of the

region’s water resources have generally tended

to decrease the volume of water in both surface and subsurface sources and to increase

the concentration of both natural and humancaused contaminants. The ability of Western

water resources to assimilate the increased

levels of contaminants that might be produced

by urban populations, industrial activities, and

use of agricultural chemicals is more limited

than in the humid Eastern United States because of lower total volumes of water. Because

of the interconnected nature of ground and surface water supplies, contamination of one will

eventually affect the quality of the other.

In discussing water quality in relation to agricultural development, two major issues arise.

On the one hand, agricultural use requires certain standards of water quality. Under conditions of water scarcity, waste products concentrating in surface or ground water supplies can

appreciably diminish the availability of suitable

water for agricultural use. On the other hand,

agriculture itself contributes waste products to

the environment affecting water quality and its

suitability for other uses.

THE EFFECTS OF WATER QUALITY ON AGRICULTURE

Technologically, water of any quality can be uses is far from complete. However, the promade suitable for any use. However, to neutral- visional threshold tolerance levels available for

ize or remove certain types of pollution from many water constituents may serve as guides

water is prohibitively difficult and expensive. in evaluating the suitability of water for parThe extent of improvement a water supply will ticular uses. In 1963 the California State Warequire and the associated costs usually repre- ter Resources Control Board published the first

sent the rationale in assessing the comparative “Water Quality Criteria” for various uses, inworth of alternative supplies. eluding agriculture (33). In 1968 the Federal

Water Pollution Control Administration pub-

“Water quality” in agriculture relates pri- lished “Water Quality Criteria” in which conmarily to farmstead water supply, livestock, siderable emphasis was given to water-quality

watering, and irrigation. Understanding the requirements in agriculture, In 1976 the Envisignificance of a great variety of water constit- ronmental Protection Agency (EPA) contribuents regarding tolerance limits for various uted “Quality Criteria for Water. ” In 1977 the
Ch. IV—Water Quality ● 8 7 — —

National Research Council of the National

Academy of Sciences published “Drinking Water and Health, ” which summarized the state

of knowledge on the effect of various drinkingwater constituents on human health.

Domestic Use on Ranches and Farms

The requirements for water quality for domestic use by a human population in an agricultural setting should not be different from requirements for drinking-water quality elsewhere. However, water available on farms and

ranches is usually in a raw state, while water

in the cities is treated to make it suitable for

human consumption. Thus, farm and ranch

water must be of such quality that it can be consumed without, or with minimal, treatment.

Because water used by individual households

in rural areas is not subject to routine quality

inspections as are public water supplies in the

cities, there is very little information on the

quality of drinking water available to rural populations. Some rural drinking-water suppIies

have become polluted. For example, analysis

of water in California during 1979 revealed that

some 100 water-supply wells contained trace

amounts of DBCP (dibromochloropropane),

formerly a widely used pesticide and a suspected carcinogenic compound (47)

.

Livestock

It is usually accepted that water that is safe

for human consumption may be used safely by

stock, but that some stock can tolerate water

of a somewhat poorer quality. According to

Heller (25,26), the maximum concentration of

salts that can be tolerated by certain domestic

animals is about 15,000 milligrams per liter

(mg/l), but this limit is believed to be too high

for food-producing animals. The maximum acceptable salinity level for livestock drinking

water suggested by EPA (50) was 3,000 mg/l of

soluble salts.

In general, the types of pollutants in water

that are of potential significance to livestock

are mineral salts, organic wastes and algae,

microbiological pathogens and parasites, pesticides, herbicides, and radionuclides, Livestock

water can be contaminated in many ways,

either directly from natural sources or indirectly; e.g., agricultural fertilizers may stimulate

algae “bloom” in the water so that it becomes

unsuitable for animal watering. Various water

pollutants may cause either loss of livestock by

death or by reduced reproduction,

lrrigation: Salts and Ions

The quality of water used in irrigation is very

important. It is known that water retained in

soil (so-called “soil solution”) tends with the

passage of time to become progressively more

saline. This process is believed to be responsible for the failure of many irrigation projects

throughout the history of civilizations (7).

Using an inferior quality water for irrigation

can affect soil by changing soil structure

(permeability and aeration), and plants through

the presence of phytotoxic substances in water

or through the modification of processes that

limit the water uptake by plants, Moreover,

some constituents of irrigation water of no particular significance to plants themselves, but

significant to animals and humans, can be accumulated by crops.

An evaluation of water suitability for irrigation based solely on water characteristics has

limitations because more factors are involved.

First, the “soil solution” is usually several times

as concentrated as the water applied (in some

cases it may be as much as 100 times more concentrated). Second, plants vary widely in their

tolerance to salinity (see ch. IX, table 67). Third,

soil types, climatic conditions, and irrigation

practices and drainage conditions are of importance and vary widely. Well-drained soil can

support growth of satisfactory crops even if the

water applied to it is not of the best quality.

However, poorly drained soils favor buildup

of undesirable constituents, even if the constituents are present in rather small quantities in

the water.

The characteristics of water most often considered in determining the suitability of water

for irrigation use are: 1) the total concentration
88 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

of salts in water (measured in mg/l or as the

specific conductance, in micromhos); 2) the

proportion of sodium to calcium and magnesium (often in percent); and 3) boron, chloride,

and sulfate content in mg/l (table 17). Each of

the characteristics varies relatively independently. Thus, water, adequate in all other respects, may not be suitable for irrigation because of a specific single adverse water-quality

factor.

Soils in arid and semiarid regions have specific salt-accumulation problems. Such soils

have been formed under limited precipitation

conditions and scarce vegetation. Infrequent

infiltration by rainwater causes the soils in

such areas to be more shallow and saline. In

order to maintain a steady state, salt accumulation in the process of irrigation should be balanced by equally effective salt removal, a difficult practice to accomplish. In most cases,

salt removal may succeed only in moving the

problem downstream to the next point at which

water is withdrawn for irrigation application.

The proportion of sodium to other cations*

in water is used to indicate the relative activity of sodium ions in exchange reaction with

*Positively charged ions,

soil, Sodium hazard increases if water has a

large concentration of bicarbonate ions. Alkaline water will act to dissolve the organic material in the soil, The effect is known under the

general term of “black alkali,” referring to the

characteristic black-grayish color of the affected soil. Because of these considerations, the

RSC* index (residual sodium carbonate) was

suggested as an additional criterion for irrigation water. Water containing more than 2.5

mg/l of RSC is probably not suitable for irrigation; with RSC in 2.5 mg/l, water is marginal,

and with RSC lower than 1.25 mg/l, water is

probably safe (53).

While trace quantities of boron in water are

essential for plants as a micronutrient, an excess of this element can cause plant injury. The

information on tolerance of plants to boron as

well as several other trace elements is presented in table 18,

Irrigation With Wastewater

In conditions of water scarcity, the reuse of

wastewater in irrigation has been considered

as a possible way to stretch available resources.

—

*RSC = (CO3 -- + HCO -3) – (CA+ + + Mg + +), Ionic content in milliequivalents per liter.

Table 17.—Summary of Classifications of Irrigation Waters

% Na EC x 106 at 25° C

Na x 100 Specific conductivity

Na + Ca + Mg + K Chlorides Sulfates (concentration Total salts

Class as meq per liter Boron, in mg/l in meq/l in meq/l of ions) in mg/l

350-2,100

I Less than 30-60°/0 Boron recommendation Less than 2-5.5 Less than 4-10 Earlier papers Up to about 700

(most recent for water of this class suggested limit of

work favors a is generally accepted about 500, but more

60°/0 limit) as less than 0.5 mg/l; recently 1,000 has

however, tolerant plants been accepted

will not be injured by

1-1.5 mg/l

II 30-75% 0.5-2.0 mg/l although 2-16 4-20 500-3,000

for tolerant plants

water with boron up to

3.35 mg/l may be

satisfactory

III More than More than 2 mg/l al- More than 6-16 More than More than More than

70-75% though water with more 12-20 2,500-3,000 1,750-2,100

than 1.0 may be highly

unsuitable for sensitive

plants

SOURCE J E McKee and H W Wolf, Wafer Quality Criteria, California State Water Resources Control Board, 1963
Ch. IV—Water Quality ● 8 9 —

Table 18.—Trace Element Tolerances for

Irrigation Waters

For water used For short-term use

continuously on on fine textured

Element all soils (mg/l) soils only (mg/l)

Aluminum . . . . . 1.000 20.00

Arsenic . . . . . . . . . 1.000 10.00

Beryllium . . . . . . . . 0.500 1.00

Boron . . . . . . . . . . . 0.750 2.00

Cadmium ... . . . . . 0.005 0.05

Chromium . . . . . 5.00 20.00

Cobalt . . . . . . . . . . . 0.200 10.00

Copper . . . . . . . . . . . 0.200 5,00

Flourine . . . . . . . . (’) (’)

Iron . . . . . . . . . . . . (’) (’)

Lead . . . . . . . . . . . . 5.000 20,00

Lithium . . . . . . . . . 5.000 5,00

Manganese . . . . . 2.000 20.00

Molybdenum . . . . . . 0.005 0.05

Nickel . . . . . . . . . . . . 0.500 2.00

Selenium . . . . . . . . . 0.050 0,05

Tin . . . . . . . . . . . . . (’) (’)

Tungsten ., . . . . . . . (’) (’)

Vanadium . . . . . . 10.000 10.00

Zinc . . . . . . . . . . . . . 5.000 10.00

SOURCE J E McKee and H W Wolf, Water Qualify Criteria, California State

Water Resources Control Board, 1963

However, the safety and desirability of land

application of wastes has been a controversial

issue, The divergence of opinion in this matter was reflected by participants of the Fourth

National Groundwater Quality Symposium in

1978. At this symposium Wright and Rovey

(both private sector water engineers) characterized such a practice as beneficial, arguing that

“land application of treated wastewater can

provide unique opportunities not only for a

final high level of waste treatment, but for reasons of nutrients as well. ” To support this conclusion, the authors presented several examples of land application of treated municipal

and industrial wastewater with no detectable

impact on ground water quality (57). In agreement, Sheaffer, the president of a company that

works with wastewater reuse, suggested that

“land treatment systems provide an opportunity to view sewage treatment as an investment

in the production of food and fiber. ” It “provides our nation with a positive program to

deal with a negatively perceived material, sewage” (41).

On the other hand, Johnson, chairman of the

National Drinking Water Advisory Council and

vice president of an environmental engineering company, characterized land application

of waste as “an accident waiting to happen. ”

He indicated that research has not been done

to give assurance that natural interaction of

wastewater and soils will remove to acceptable

levels potentially harmful contaminants. He

cited several examples where sewage effluents

penetrated the ground to the water level,

“There is a great deal to be learned, ” he said,

‘‘about the fate and transport of contaminants

below the surface; the practices that represent

the greatest threat to this national resource; and

the economics of alternative ways of disposing of wastes in a manner more protective of

the environment, ” Johnson quoted California

State studies in 1976 that concluded that “areas

of uncertainties regarding health effects cannot be resolved because basic scientific knowledge is lacking” (29).

A 1979 report by the United Nations World

Health Organization (WHO) warned that the

application of wastewater to land, whether for

agricultural irrigation or as a method of treatment for disposal, poses a possible risk of virus

contamination of ground water. The report emphasized that “concern about hazard from viruses caused by this practice has only recently been raised, and available information remains limited. ” Concentration of enteric viruses in human feces was reported to be as

high as 105 to 108 PFU/g (plaque-forming units

per gram) (56), Raw sewage and wastewater

usually contain a large number of enteric viruses of human origin, Although sewage treatments reduce virus contamination to varying

extents, significant numbers of viruses survive

treatment.

Because viruses in wastewater that is applied

to land can survive in the environment for a

considerable period of time (27), the application

of inadequately treated effluents and sludge to

land poses the risk of potential public health

problems, According to the 1979 WHO report,

deposition of significant concentrations of

viruses on the soil might be a health hazard via:

direct virus infection of farmworkers and

their contacts,

virus contamination of crops destined for

human consumption,

25-160 0 - 7 : QL 3
90 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— . —

●

●

●

virus contamination of the drinking-water

source (surface contamination by runoff

or ground water contamination by percolation),

dissemination of viruses by insect vectors

or animals in contact with contaminated

soil, and

virus dissemination by the air when

sprinkler irrigation is u-seal.

An improved understanding of factors that

influence virus retention and inactivation in

soil and of factors controlling virus migration

through soil is critical in managing wastewater

land-treatment systems. According to studies

by Gerba, et al. (19), virus retention in soil is

believed to occur mainly by the mechanism of

adsorption, * which, in turn, is controlled by

a number of variables; e.g., soil composition

and ionic content, pH, moisture content, temperature, rates of wastewater application,

strength of sewage (19,27). Moreover, adsorptive behavior of viruses and their survival were

also demonstrated to be strongly type- and

strain-dependent. Hurst, et al. (27), reporting

this observation in 1980, stated:

The fact that [adsorptive capacity] significantly affected virus survival is of great importance. This finding indicates a dilemma insofar

as virus inactivation during land treatments is

concerned. On one hand, concern for public

health would, of necessity, require that land

treatment sites be developed on soils with high

virus adsorptive capacity. This is required to

minimize the possibility of viruses applied to

soil reaching groundwater. On the other hand,

virus survival is likely to be greatest in those

soils that would be most effective in preventing groundwater contamination.

*Adherence of one particle, ion, or molecule to the surface

of another.

Heat

Water-temperature increases can result from

industrial water use and from water impoundment, Such increases have a direct effect on

the efficiency of water as a coolant and an indirect influence on aquatic life and on water

chemistry. A change in water temperatures, by

itself, has little effect on the agricultural uses

of water. However, changes in water temperature may produce associated water-quality

changes which will render the water less desirable for a variety of agricultural uses. For

example, an increased water temperature increases the volubility of all substances including those that may be harmful to agriculture. With higher water temperatures the dissolved oxygen content is lowered, increasing

the possibility of eutrophication, including the

production of anaerobic decomposition products and increased algae growth, when sufficient nutrients are present. Pathogenic organisms will survive for longer periods of time

at higher water temperatures, thus increasing

the risk of disease transmission both to and

from agricultural areas.

Radioactive Substances

The possibility of the uptake and translocation by plants of the radioactive material from

fallout—in particular strontium, cesium, barium, and iodine—has been identified in some

literature (33). Radioactive material can be

picked up by rivers as they cross areas of

uranium mining (7)0 Uranium mining exists in

several States—e. g., Utah, New Mexico, Arizona, and Texas. Some streams used for irrigation purposes either cross through uranium

districts or originate within the uranium districts (9,55). Ground water can also be contaminated in the process of uranium exploration.

THE EFFECTS OF AGRICULTURE ON WATER QUALITY

Agriculture contributes its share of water pol- The impact of agricultural wastes such as sedlution, both from point and nonpoint sources, * iments, dissolved salts, and bacteria on water

● Point pollution comes from sources that can be pinpointed; quality has been given comparatively little atnonpoint pollution comes from diffuse sources. See app. E. tention until recently (14,51). Within the past
Ch. IV—Water Quality ● 9 1

— —

several decades the use of agricultural chemicals (pesticides and fertilizers) has become

widespread in the West, and a sizable feedlot

industry has been created with massive concentrations of livestock, poultry, and the resultant waste products. These kinds of activities

raise serious concerns about Western water

quality,

Suspended Sediments

The greatest mass of waste resulting from

agricultural activity in terms of quantity is

probably the material eroded from cultivated

land. The total quantity of sediment production in the United States is appreciable, estimated to be as much as 6.4 billion tons per year

(11). Waterborne sediments are solid particles

of various sizes composed of inorganic and organic materials eroded from soil and rocks,

products of plant and animal decomposition,

and debris of human activity.

Much sediment and erosion results from

poor agricultural management practices according to a report prepared by the Department

of Agronomy at Cornell University (14). The

problem is magnified by numerous individual

farmers who, either for lack of knowledge,

carelessness, or economic necessity, do not

practice proper methods of erosion control,

manure application, or agricultural chemical

application.

Although there is no evidence that common

suspended sediments or solids affect health

directly, they can affect health indirectly. Specifically, clays are very adsorptive and can provide a transport mechanism for viruses, bacteria, and various toxic substances into drinking-water supplies. Pesticides and fertilizers

bind to soil particles and are later mobilized

by erosion and transported by runoff. Paraquat

and Diquat (herbicides) and phosphorus (fertilizer) are examples of chemicals that can be

transported by clay particles (36). Viruses and

bacteria tend to concentrate in the bottom sediments of lakes, rivers, and estuaries (22,32,36],

Some organic pollutants that do not adsorb

readily on pure clays adsorb on clay-organic

is usually capable of removing most of the

suspended material; in cases when it is not,

such material may be ingested, Pollutants

bound to clay particles may be released into

the water or into the digestive tract of humans

and animals.

Other problems commonly reported in association with waterborne sediments come from

agriculture. These include impairment of

drainage, reduction of reservoir storage capacity, and increased need for dredging of waterdevelopment projects. Waterborne sediments

increase costs of water clarification for industrial use and potable water delivery. Coarse

sediments cause abrasion of turbine blades in

power-generation facilities and clogging of injection wells, Economic losses to commercial

fisheries can result from the effects of sediment

on spawning grounds.

Nutrient transport from cultivated land and

feedlots is among the most frequent problems

associated with agricultural activity. While elements such as phosphorus and nitrogen are essential nutrients for any terrestrial or aquatic

ecosystem, the overenrichment of water bodies

with these same chemicals may bring about

an uncontrolled algae “bloom” and excessive

growth of aquatic plants. This growth leads to

problems in waterways and canals and interferes with water recreation and other beneficial

uses of water. Decaying water plants reduce

the quality and length of the useful life of farm

ponds, lakes, and reservoirs.

Phosphorus

According to some experts, phosphorus may

be one of the most limiting nutrients in aquatic

habitats. Agricultural sources of phosphorus

include fertilizer and runoff from animal feedlots. Phosphorus, unlike nitrogen, does not

readily leach out of soil. Soil can hold large

quantities of this nutrient in a fixed state. Erosion and sediment transport is the primary way

in which phosphorus is introduced into water

complexes in the sediments. Water treat-merit bodies. phosphorus commonly is present in
92 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands — —-.. .—

greater concentration in the bottom sediments

of a water body than in solution.

Some research has shown that algae “bloom”

can exist at phosphorus concentrations in

water as low as 0.1 ppm. However, such algae

could not sustain itself for long at this initial

concentration unless phosphorus were resupplied at least 15 times throughout the growing

season (14). It is believed that the amounts of

phosphorus moving off the land as fertilizer

may not be sufficient to support the algae

“bloom” experienced in farm ponds, lakes, and

reservoirs, Runoff from barnyards, animal

feedlots, and domestic sewage also contribute

phosphorus to water.

Nitrogen

A second nutrient and potential water pollutant is nitrogen. Nitrate contamination is

likely to be of importance where rural water

supplies are concerned. Major sources of nitrogen-containing wastes are drainage from animal feedlots, irrigation reuse water, wastewater from municipalities and industries, solid

waste dumps, and septic tanks. An important

nonpoint source is runoff from fertilized land

(chemical or manure) (36). It has also been suggested that some nitrates in ground water are

of a natural origin—i.e, indigenous to some geological deposits—e.g., tertiary and quartenary

sands (18). The origin of excessive nitrates in

shallow wells is a subject of debate. Several

recent reports from the United States and England have suggested trends of increased nitrates in water attributed principally to the increasing use of organic and inorganic fertilizers in areas of arable farming and to changes

in methods of farming (16,24,58).

IMPACTS ON HUMAN HEALTH

An excessive intake of nitrate or nitrite leads

to the development of methemoglobinemia. *

The effect has been well documented in humans, and a similar effect has been observed

in animals exposed to high doses of these

chemicals (36).

*Presence of methemoglobin (a chemically altered hemoglobin

which does not combine with oxygen) in the blood results in

cyanosis (bluish discoloration due to deficient oxygenation of

the blood].

Evidence implicating nitrate, nitrite, and Nnitroso compounds in the development of cancer in humans is circumstantial. Several epidemiological studies of certain geographical/

nationality groups have provided data that are

consistent with the hypothesis that exposure

of humans to high levels of nitrate and nitrite

may be associated with an increased incidence

of cancers of the stomach and esophagus (see,

e.g., 2,13,59), In none of these studies was there

a direct attempt to investigate actual exposures

of nitrate, nitrite, or N-nitroso in individuals

who developed cancer, however. In most of the

studies, several other plausible causative agents

were also identified (36).

Many N-nitroso compounds are clearly carcinogenic in many species of laboratory animals, suggesting that they should be considered

as possible human carcinogens. However, the

value of these tests in making predictions of

the nature or extent of risk to humans is unknown (36). It has been recommended that exposure to the precursors of N-nitroso compounds—especially nitrate and nitrite—and to

preformed N-nitroso compounds be reduced

(36), A thorough discussion of pathology associated with N-nitroso compounds is available

in a publication of the International Agency for

Research on Cancer (28).

IMPACTS ON ANIMALS

Cattle, sheep, goats, horses, swine, and birds

are farm animals susceptible to nitrate poisoning which occurs when nitrate is ingested

faster than it can be reduced and incorporated

into proteins. In such a situation, nitrite is then

absorbed into blood where it converts hemoglobin into methemoglobin, This reaction reduces the oxygen-carrying capacity of blood,

and the animal then experiences oxygen deprivation and may die by asphyxiation. Other

consequences are spontaneous abortion, reduced production of milk, and signs of vitamin

A deprivation.

Dissolved Salts

A favorable mineral salt balance in the soil

is essential for human survival and for successful functioning of agriculture. Water that
evaporates from the soil surface or is transpired by the plants is salt-free, and thus salt

residue tends to be left behind not only in the

soil but also in any water flowing through the

field. As a result, the irrigation return flow

usually has a much higher salt burden than

does the incoming water.

Wadleigh (51) has suggested that irrigation

does not actually produce waste in the form

of dissolved salts nor add much to this salt

burden by the application of chemical fertilizers. He suggests that irrigation transfers the salt

loads in a more concentrated form into return

flows from irrigation. The increased salt burden of irrigation drainage water renders the

water of receiving streams and rivers less suitable for downstream users. Progressively higher salt concentrations of irrigation return flows

may render receiving waters unfit as a potable

water supply or for other uses.

Sodium is one of the salts that may buildup

in relatively high proportions in irrigation

return flow as water on the field evaporates.

The impact of sodium excess on nonagricultural uses of water—in particular, water designated for human consumption—has not received widespread recognition. Sodium is a

life-essential element, and the amount that can

be tolerated by healthy people is believed to be

considerable. For people suffering from some

illnesses, however, excessive intake of sodium

(salt) is undesirable, and might be harmful.

These illnesses include congestive heart failure,

hypertension, liver cirrhosis, renal disorders,

adrenal hyperfunction, and possibly certain

complications of pregnancy.

The U.S. Public Health Service limits the

total dissolved solids in water destined for

human consumption to 500 mg/l and the chloride content to 250 mg/l. A report of the National Research Council (38) indicates that over 6

million people in the United States are on physician-prescribed salt-restricting diets. When

drinking water contains sodium in a concentration greater than 20 mg/l, compliance with

restricted diets of 1 g or less daily becomes difficult. In view of this fact, the American Heart

Association (1) recommended that the amount

Ch. IV—Water Quality ● 9 3

—

of sodium in water for use in salt-limiting diets

shall not be in excess of 20 mg/l. White, et al.

(52), found that many municipal water supplies

are unsuitable for patients on severely restricted sodium-salt diets. Drinking water containing sufficient sodium to interfere with the

aims of salt-limiting diets had been reported

by Krishnaswami (31), Cech, et al. (10), and

Gonzales, et al. (21).

Animal and Other Organic Wastes

The tendency in animal husbandry toward

huge confinement-type operations with feedlots containing thousands of cattle and hogs

and hundreds of thousands of poultry creates

massive and serious waste problems. It has

been estimated that domestic animals produce

over 1 billion tons of fecal material a year and

animal liquid sewage amounts annually to 400

million tons (51). Together with other wastes,

such as animal carcasses, the total amount of

waste products from animal husbandry is estimated to be around 2 billion tons per year;

about half of this is generated in concentrated

confinement-type operations.

One of the problems in coping with animal

waste stems from its high biochemical-oxygen

demand (BOD), the amount of oxygen necessary to decompose organic material present in

water, A feedlot of 10,000 cattle may produce

a sewage-disposal problem equal to that of a

city of more than 160,000 people. The major

differences are that sewage from a city of this

size would be diluted in about 8 million gallons

of water, while feedlot wastes are undiluted.

Also, most cities are served by some form of

sewage treatment facilities, while often feedlots

are not. Table 19 provides estimated population equivalents of the fecal production by animals expressed in terms of BOD.

Other sectors of agricultural manufacturing

are also known to contribute wastes with high

BOD, These include fruit canning; sugar refining, fermenting, and distillation; animal slaughterhouses; meat processing; dairy cleaning;

wool processing; and cotton manufacturing

(51). Also, runoff of decaying products from
94 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 19.—Population Equivalent of the Fecal

Production by Animals in Terms of

Biochemical Oxygen Demand (BOD)

Relative

BOD per

Fecal unit of waste Population

Biotype G./cap./day (lb) equivalent

Man . . . . . . . . . . . . 150 1.00 1.00

Horse . . . . . . . . . . . 16,000 0.105 11.30

cow . . . . . . . . . . . . 23,600 0.105 16.40

Sheep. . . . . . . . . . . 1,130 0.325 2.45

Hog . . . . . . . . . . . . 2,700 0.105 1.90

Hen. . . . . . . . . . . . . 182 0.115 0.14

SOURCE E. H. Wadleigh, Wastes in Relation to Agriculture and Forestry, USDA

Miscellaneous Publication No. 1085, 1988

plant residues on farms and ranches contributes organic materials to the receiving water

bodies.

Oxygen-demanding wastes act to impair the

quality of the receiving water. Common effects

are depletion of oxygen in bacterial decomposition of organic wastes, changes of conditions

in the water from aerobic to anaerobic (putrid),

characteristic foul odor, and algae “bloom,”

Water-Treatment Problems

Undesirable effects on water supplies from

the overload of oxygen-demanding organic

wastes is comparatively well recognized. Recently, however, other problems related to high

organic content in receiving water have been

identified. When such water is subjected to

chlorination at water-treatment plants, some

exotic compounds are synthesized by chlorine

interactions with organics (4,40). The compounds so formed are collectively known as

trihalomethanes (chloroform, bromoform, bromodichloromethane, and dibromochloromethane). Some of these compounds are recognized

animal carcinogens and suspected human carcinogens.

The cancer-causing potential of one of these

trihalomethanes, chloroform, was suggested as

early as 1945 by Eschenbrenner from studies

with mice. These results were confirmed later

by the National Cancer Institute (37) which

reported that chloroform induces certain kinds

of tumors in male and female rats. The carcinogenic properties of a related compound, carbon tetrachloride, were demonstrated also with

rats and mice, and a possible accumulation of

this compound in blood plasma was reported

by Dowty and associates (15).

The mutagenic properties of two other trihalomethanes (bromoform and dibromochloromethane) were demonstrated by Simmon and

Poole (43) and by Theiss, et al. (46). Brungs (5),

in assessing the effect of chlorination of wastewater effluents on aquatic life, concluded that

the end-product compounds created after chlorination of wastewater are often entirely different from the original material and are more

toxic.

In 1974, EPA undertook the National Organic Reconnaissance Survey that included 80

U.S. cities (45). Chloroform was detected in the

drinking water of 95 percent of those cities. It

was concluded that trihalomethanes were

probably present in almost all drinking water

disinfected with chlorine. They are more likely to occur in higher concentrations when surface water is the source of raw water because

the organic content of raw water is high,

when prechlorination is used, and when the

dose of chlorine required to disinfect water is

high.

Several epidemiological studies have been

carried out to address the association between

chlorination and cancer mortality (see, e.g.,

9,30,44). Comprehensive reviews have been

written by Wilkins, et al. (54), Shy and Struba

(42), and Crump and Guess (12), While differences of opinion with respect to existing evidence are still considerable, prudence dictates

increased efforts to reduce the organic load in

water destined for drinking. In February 1978,

EPA amended the National Interim Primary

Drinking Water Regulation by setting a maximum contaminant level (MCL) at 0.1 mg/l for

trihalomethanes in community water systems

serving populations greater than 75,000 persons and by specifying trihalomethane monitoring requirements for smaller communities.

To meet these regulations, some cities have to

remove or reduce the content of precursororganics in raw water prior to its treatment
Ch. IV—Water Quality . 95

—

with chlorine, which means that the burden of

dealing with the high organic load falls on

municipalities.

Waterborne Infectious Diseases

Agricultural wastes also are important potential sources of infection, Leachates from barnyards and feedlots carry animal-disease agents.

Residues and litter from crops, orchards, and

forestry operations are often sources of plant

diseases and breeding places for insects.

Many animal diseases are infections shared

by humans and other vertebrates. Table 20

shows selected diseases of worldwide distribution and/or relevance in the United States. The

list is by no means all inclusive. It is, however,

illustrative of a number of diseases shared by

animals and humans for which water is known

or suspected to be the route, or one of several

routes, of transmission.

Agricultural Chemicals

According to a recent FDA report, more than

300 exotic chemical compounds are in use in

the agricultural sector of the United States and

other countries (39). The word ‘‘pesticide” encompasses categories of chemicals such as:

insecticides—agents designated to control

insect pest infestations of plants, animals,

and humans;

herbicides or defoliants—chemicals designated to control undesirable plants in the

vicinity of beneficial plants (including

aquatic plants);

fungicides–chemicals used for control of

fungal growth;

rodenticides—chemicals that control rodents that would otherwise consume farm

products;

fumigants—gases or aerosols used to control pest organisms in the soil or in buildings; and

larvicides and molluscicides–agents that

control undesirable larval or mollusk populations in terrestrial or aquatic environments,

Historically, the use of pesticides has been

of great value to society. For example, pesticides have helped control insect carriers of

various communicable diseases (typhus, malaria] and have increased the agricultural output

of food, Tschirley (48) has pointed out that despite intensified and accelerated research on

alternative methods of pest control, there will

probably be some continuous need for chemical pesticides. He has stated that “agricultural

scientists cannot conceive of producing an adequate supply of food, feed, and fiber on the

acreage now used for agriculture without judicious use of pesticides. ”

The unauthorized or careless use of pesticides may, and has been known to, cause harm.

For some pesticides the margin of error is very

small (48). Acute effects from unintended exposure to a large dose of toxic chemicals have

been recognized. Quite another matter is the

question of the impact of chronic human exposure to trace levels of pesticides distributed

in the environment. This issue is much more

complex, sensitive, and unsettled.

When pesticides are applied, it is very difficult to avoid an exposure of nontarget organisms in the vicinity. Some chemicals decompose readily and rapidly in the soil and thus

are of little concern. Others, however, tend to

persist for an appreciable length of time and

become widely distributed in the environment,

across land, water, and air.

Some resistant and fat-soluble pesticides tend

to concentrate in animal tissues and to magnify

biologically in the successive steps in the food

chain. The concern over such persistence and

accumulation in the environment and also in

tissues of fish, birds, wild and domestic animals, and humans has brought notoriety to one

group of insecticides, the chlorinated hydrocarbons. Other agricultural chemicals may be contaminated with a toxic byproduct of manufacture, dioxin, Many chemicals, currently

banned, may continue to reside in the environment, being carried by and deposited in water

which is then applied to other uses, The following discussion is illustrative of the concern in

this complex and difficult area over past and
.-

Table 20.—Selected Infections and Infestations Shared by Humans and Vertebrate Animals

Principal Known

animals involved geographical Probable means

Disease Causative organism bacterial diseases distribution of spread

Anthrax

Brucellosis

Melioidosis

Salmonellosis

Staphylococcus

Streptococcus

infections

Tuberculosis

Tularemia

Bacillus anthracis

Brucella abortus

Brucella melitensis

Brucella suis

Brucella canis

Pseudomonas

pseudomallei

Salmonella spp.

(2,000 serotypes)

Staphylococcus spp.

Streptococcus species. Some

species host-specific and only

accidentally are the cause of

disease in humans

Mycobacterium bovia

Cattle, sheep, goats, horses, and

wiId herbivorous animals

CattIe

Goats and sheep

Swine, caribous

Dogs

Rodents, sheep, goats, horses,

swine, nonhuman primates, and

kangaroos

Poultry, swine, cattle, horses,

dogs, cats, wild animals and

birds, reptiles, amphibia, and

crustacea

Domestic animals

Domestic animals

Cattle, nonhuman primates

Rabbits, dogs, cats, rodents, and

sheep

Worldwide

Worldwide

Asia, Australia, East India,

South America, and United

States

Worldwide

Worldwide

Worldwide

Worldwide, except for countries that have eliminated the

disease in cattle

Circumpolar in northern

hemisphere of America,

Europe and Asia

Occupational exposure (hand

dead animals) occasionally

recreational exposure, from

wounds or insect bites. Rarely

airborne or food borne. Waterborne in animal to animal

transfer

Occupational exposure. Foodborne. Waterborne in animal

to animal transfer

Exposure and ingestion.

Organism lives in soil and

water

Ingestion, occupational and

recreational exposure. Wound

infection

Ingestion and contact

Ingestion and contact

Ingestion, inhalation, and occupational exposure

Organism is capable of surviving in water

Occupational (hunters) and

recreational exposure to

water, insect bites, and

ingestion

SOURCE Abstracted from Cech, 1983 Original source” U S Department of Health and Human Services, Public Health Service, Centers for Disease Control, Center for Infectious Diseases and the Off Ice of Biosafety

Atlanta, Ga and the University of Texas School of Public Health, Health Science Center, Houston, Tex. Revised in 1982. Courtesy of Professor James Steele, D V M
. — —

Ch. IV—Water Quality . 97 —

present uses. A number of new products enter

the agricultural market every year.

Chlorinated Hydrocarbons

Chlorinated hydrocarbons include Aldrin,

Dieldrin, Endrin, Chlordane, Heptachlor, Oxychlordane, and Heptachlor Epoxide. (These

compounds are grouped under the common

term “cyclodienes.”) Tables 21 and 22 illustrate

pesticide concentrations reported in animal

milk and human milk. Cyclodiene insecticides

have been recognized as animal carcinogens.

NAS (36) has characterized this group as “the

most hazardous of all pesticides because of

their persistence, fat storage, and central nervous system target site. ” In conclusions and recommendations on cyclodiene pesticides, the

NAS report states:

The cyclodiene insecticides—particularly the

persistent expoxides, Dieldrin, Endrin, Heptachlor Epoxide, Oxychlordane—present the

greatest hazards of all residual pesticides in

water. At low dosages, they are highly active

hepatocarcinogens and have a dangerous effect on the central nervous system of man and

Table 21 .—Organochlorine Insecticides in Illinois

From Cow’s Milk (ppm)

Insecticide 1971 1972 1973 Average

Chlordane . . . . 0.02 0.04 0.06 0.05

DDT . . . . . . . . . 0.05 0.02 0.03 0.03

Dieldrin . . . . 0.08 0.04 0.08 0.07

Heptachlor . 0.03 0.03 0.05 0.05

Lindane . . . . . Trace 0.02 0.03 0.02

Note Of 200 Samples analyzed, 87% were positive for chlordane, 92% for dieldrin,

93% for heptachlor, and 81% for Iindane

SOURCE A Curely and R Kimbrough, “Chlorinated Hydrocarbon Insecticides

I n Plasma and Milk of Pregnant and Lactating Women, Arch Environ

Health, vol 18, 1969, pp 156.164

Table 22.–Pesticides in Human Milk

Concentration, ppm

Insecticide Mean Range

Dieldrin . . . . . . . . . 0.0073 0.0029-0.0146

Heptachlor epoxide. ., . . . . 0.0027 <0.0001-0.0044

DDT-T . . . . . . . . . . . . . . . . . . 0.0027 0.0404-0.1563

SOURCE A- Curley and R Kimbrough, “Chlorinated Hydrocarbon Insecticides

in Plasma and MI I k of Pregnant and Lactating Women, ’ Arch. Environ.

Health, vol 18, 1969, pp 156-164

higher animals, leading to apparently irreversible changes in encephalographic and behavioral patterns , , . .

and further:

In light of the above and taking into account

the carcinogenic risk projections, it is suggested that very strict criteria be applied when

limits for Dieldrin, Heptachlor, and Chlordane

in drinking water are established.

According to NAS (36), perhaps 600 million

pounds of these compounds have been dispersed into the soil, air, water, and food of the

United States during the last several decades,

and little is truly known about the fate of these

compounds. It is recognized, however, that

they are very stable compounds and, because

of certain properties, become widely distributed throughout the environment.

Traces of these insecticides and their stable

byproducts have been found in water nearly

everywhere in the United States. The following average concentrations were reported by

Breidenback and coworkers in 1967 (5):

Aldrin, <O.001–O.006 parts per billion (ppb)

Dieldrin, 0.08-–0.122 ppb

Endrin, 0.008–0.2144 ppb

Heptachlor, 0–0.0031 ppb

Heptachlor Epoxide, 0.001–0.008 ppb.

Samples of finished drinking water taken in

the late 1960’s and early 1970’s from the Mississippi and Missouri Rivers were positive for

Dieldrin, Endrin, and Chlordane. Surveys of

drinking water have identified traces of cyclodienes in public water supplies in Miami, Seattle, Cincinnati, New Orleans, and other cities.

Water treatment apparently is incapable of

totally removing these pesticides even with activated carbon filters (36).

pesticides are regulated under the Federal

Insecticide, Fungicide, and Rodenticide Act

(FIFRA). This act, as Tschirley (48) pointed out,

is essentially a “labeling law, ” It allows the reg

-

istration of so-called “economic poisons” by

the U.S. Department of Agriculture [USDA) in

situations where products are designated for

interstate commerce. It further allows the seizures of unregistered or insufficiently labeled

pesticides. In 1972 an amendment to FIFRA
98 . water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

was passed, giving EPA the authority for control over end-uses of pesticides.

The cyclodiene insecticides Aldrin and

Dieldrin were banned by EPA on October 1,

1974. Chlorodane and heptachlor registrations

were suspended for use on agricultural crops

on April 1, 1976. DDT was another chlorinated

hydrocarbon insecticide in widespread use

from World War II until its ban in 1972. *

Because of its slow biodegradation and highfat volubility, this chemical also became widespread in the environment. DDT has been detected in milk and many other food products.

Table 23 shows daily dietary intake estimated

for an average 16- to 19-year-old U.S. male in

the period 1965-70. The significance of these

residues in the environment is not adequately

known.

Dioxin

Contamination of irrigation water with herbicides was reported by the Federal Water

Pollution Control Administration in 1968. In

recent years the herbicide of phenoxy-type

2,4,5-T and also 2,4,5-TP (Silvex) have received

much attention, mainly in connection with

their associated chlorinated dioxin, TCDD (or

2,3,6,8 -tetrachlorodibenzo-p-dioxin). By itself,

2,4,5-T (or 2,4,5 -trichlorophenozyacetic acid)

herbicide is only moderately toxic. However,

it is now known that manufacturing of 2,4,5-T

herbicide is accompanied by formation of an

extremely toxic byproduct, TCDD, or dioxin,

and that this dioxin may be present as a con-

*DDT and DDT-related products, DI)D (2,2 -(p-chloropheny l)-l,

l-dichloroethane) and DDE (2,2 -bis-(p-chlorophen yl]-l,

I-dichloroethylene) are collectively known as DDT-T.

Table 23.—Pesticides in Diet

Daily dietary intake, mg

6-yr

Pest icicle 1965 1966 1967 1968 1969 1970 average

DDT . . . . . . 0.031 0.041 0.026 0.019 0.016 0.015 0.025

DDE . . . . . . 0.018 0.028 0.017 0.015 0.011 0.010 0.017

DDD . . . . . . 0.013 0.018 0.013 0.011 0,005 0.004 0.011

DDT-T . . . . . 0.062 0.087 0.056 0.045 0.032 0.029 0.053

SOURCE” National Academy of Sciences, National Research Council, Drinking

Wafer and Heallh (Washington, D C U S Government Printing Office,

1977)

taminant of technical grade herbicide 2,4,5-T

and also Silvex.

The President’s Scientific Advisory Committee (Panel on Herbicides) moved in 1971 that,

in the future, production of 2,4,5-T herbicide

shall not contain more than 0.1 mg/kg of dioxin as a contaminant (it has not been feasible

to produce 2,4,5-T herbicide totally free of dioxin), Existing stock manufactured before 1971

was allowed to be marketed only if dioxin was

limited to 0.5 mg/kg,

According to the Council on Scientific Affairs of the American Medical Association Advisory Panel on Toxic Substances (3), at one

time as much as 70 ppm of the dioxin TCDD

was present in the commercial formulation of

these herbicides. Since manufacturers have become aware of the problem, products contain

dioxin impurities at levels normally below 0,01

ppm. Dioxin maybe generated during incineration of some chlorinated compounds in industrial and municipal wastes and by burning vegetation treated with phenoxy-type herbicides,

Dioxin is not particularly soluble in water,

but it binds tightly to clay particles and thus

can be carried into water by sediment transport. This compound is toxic at extremely low

levels, much below the reliable limits of detection, Dioxin “may well be one of the most toxic substances known to man, ” according to the

Advisory Panel on Toxic Substances of the

American Medical Association (3). Symptoms

of exposure to dioxin have been reported as

chloracne, impaired liver function, nephropathy, irritation of gastrointestinal tract, depression, and irritation of nervous system (36).

Pathological changes in the liver, peripheral

nerves, blood-forming organics, and the reticuloendothelial system (3) have also been noted,

In assessing the situation with regard to toxicity and the long-term health effects of dioxin, the Advisory Panel on Toxic Substances

formed by the Council on Scientific Affairs reported that “although data from studies on experimental animals tend to support some of

these claims, it is not certain that the animal

data are extrapolatable to man” (3). The council therefore recommended a continuation and
Ch. IV-Water Quality ● 9 9

——-.——

expansion of the studies of exposed or allegedly

exposed persons to alert all physicians through

American Medical Association publications to

the possible adverse effects and signs of dioxin exposure and to enlist their cooperation in

the collection of vitally needed information.

DBCP

Another example of recent concern over

agricultural chemicals that may still be polluting the water supply and affecting humans is

DBCP (dibromochloropropane)—an agricultural chemical widely in use prior to 1977. In 1977

it was reported that DBCP had caused infertility in male factory workers exposed to it.

Studies initially conducted in the agricultural

chemical plant in Lathrop, Calif., and later in

three other DBCP manufacturing plants, found

a total of 100 cases of abnormally low-sperm

counts (49). In September 1977, DBCP was

banned from manufacturing and agricultural

application in the United States.

According to Glass and associates (20), workers who applied this chemical in the field situation were probably the largest group of people

exposed to this nematocide. Glass pointed out

that prior to the ban on DBCP in 1976, several

thousand independent farmers and professional pesticide applicators in California alone applied more than 1 million pounds of this chemical to more than 50,000 acres of land.

Public Health Effects

In 1977, the NAS National Research Council reported that a large number of synthetic

organic compounds had been detected in

drinking water in the United States. From the

compounds known to be present in water, a

fraction were selected for detailed review of

their health significance. Among compounds

selected for scrutiny were 55 pesticides and 74

nonpesticide organic chemicals. It was indicated that some of the pesticides studied had

not been observed in drinking water but were

included because of their widespread and

heavy use.

Of the pesticides studied, 23 compounds

were identified for which positive data on carcinogenesis existed. These compounds are

listed in table 24. The category of confirmed

animal carcinogens included such well-known

pesticides as Dieldrin, Heptachlor, Chlordane,

DDT, Lindane, B-BHC, Aldrin, Kepone, and

several others, The insecticides Endrin and

Heptachlor Epoxide and the fumigant Bis (2-

chlorethyl ether) were classified as “suspected

animal carcinogens. ”

In this NAS study, data to estimate risk from

human exposure varied widely. For some compounds it was possible to estimate acceptable

daily intake (table 25); for others it was not

possible (table 26), As a result of its assessment,

NAS (36) concluded that:

The potential for existing concentrations of

organic pesticides and other organic contaminants in drinking water to adversely affect

Table 24.—Categories of Known or Suspected Organic

Chemical Carcinogens Found in Drinking Water

Highest observed

concentrations in

finished water,

Compound μ/liter

Human carcinogen:

Vinyl chloride . . . . . . . . . . . . . . . . . . . . . . 10

Suspected human carcinogens:

Benzene . . . . . . . . . . . . . . . . . . . . ... . . . 10

Benzo (a) pyrene . . . . . . . . . . . . . . . ., . . D

Animal carcinogens:

Dieldrin . . . . . . . . . . . . . . . . . . . . ., . . . . . . 8

Kepone . . . . . . . . . . . . . . . . . . . . . . . . . . . . ND

Heptachlor . . . . . . . ... ... . . . . . . . . . D

Chlordane. . . . . . . . . . . . . . . . . . . . . . . . . . 0.1

DDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D

Lindane (7-BHC) . . . . . . . . . . . . . . . . . . . . 0.01

ßBHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D

PCB (Aroclor 1260) . . . . . . . . . . . . . . . . . . 3

ETU

Chloroform . . . . . . . . . . . . . . . . . . . . . . . . . 366

a-BHC . . . . . . . . . . . . . . . . . . D

PCNB . . . . . . . . . . . . . . . . . . . . . . . . . . . . ND

Carbontetrachloride . . . . . . . . . . . . . . . ., 5

Trichloroethylene . . . . . . . . . . . . . . . . . . . 0.5

Diphenylhydrazine 1

Aldrin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D

Suspected animal carcinogens:

Bis (2-chloroethyl) ether. . . . . . . . . . . . . . 0.42

Endrin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 008

Heptachlor eposide . . . . . . . . . . . . . . . . . D

D = Detected but not quantified, ND= Not detected

SOURCE National Academy of Sciences, National Research Council, Drinking

Water and Health (Washington, D C U S Government Printing Office,

1 977)
100 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 25.—Organic Pesticides and Other Organic Contaminants in Drinking Water, Concentration,

Toxicity, ADI, and Suggested No-Adverse-Effect Levels

Maximum dose

Maximum producing no

observed observed

concentrations adverse effect, Uncertainty ADl

b

Compound in H20, μg/liter mg/kg/day factor a mg/kg/day

0.04 12.5 1,000 0.0125

100 0.1

2,4-D . . . . . . . . . . . . . . . . . . .

2,4,5-T . . . . . . . . . . . . . . . . . .

TCDD . . . . . . . . . . . . . . . . . . .

2,4,5-TP . . . . . . . . . . . . . . . . .

MCPA . . . . . . . . . . . . . . . . . .

Amiben . . . . . . . . . . . . . . . . .

Dicamba . . . . . . . . . . . . . . . .

Alachlor . . . . . . . . . . . . . . . .

Butachlor . . . . . . . . . . . . . . .

Propachlor . . . . . . . . . . . . . .

Propanil. . . . . . . . . . . . . . . . .

Aldicarb . . . . . . . . . . . . . . . .

Bromacil . . . . . . . . . . . . . . . .

Paraquat . . . . . . . . . . . . . . . .

Trifluralin (also for

Nitralin and Benefin . . . .

Methoxychlor . . . . . . . . . . . .

Toxaphene . . . . . . . . . . . . . .

Azinphosmethyl . . . . . . . . . .

Diazinon . . . . . . . . . . . . . . . .

Phorate (also for

Disulfoton) . . . . . . . . . . . .

Carbaryl. . . . . . . . . . . . . . . . .

Ziram (and Ferbam). . . . . . .

Captan. . . . . . . . . . . . . . . . . .

Folpet . . . . . . . . . . . . . . . . . .

HCB . . . . . . . . . . . . . . . . . . . .

PDB . . . . . . . . . . . . . . . . . . . .

Parathion (and Methyl

parathion) . . . . . . . . . . . . .

Malathion . . . . . . . . . . . . . . .

Maneb (and Zineb) . . . . . . .

Thiram . . . . . . . . . . . . . . . . . .

Atrazine. . . . . . . . . . . . . . . . .

Propazine . . . . . . . . . . . . . . .

Simazine . . . . . . . . . . . . . . . .

Di-n-butyl phthalate . . . . . . .

Di (2-ethyl hexyl) . . . . . . . . .

Hexachlorophene . . . . . . . .

Methyl methacrylate . . . . . .

Pentachlorophenol . . . . . . .

Styrene . . . . . . . . . . . . . . . . .

detected d

2.9

0.06

detected

6.0

1.0

5.1

detected

detected

5.0

30.0

0.01

1.0

1.4

1.0

10.0

1 0

- 5

0.75

1,25

250

1.25

100

10

100

20

0.1

12.5

8.5

10

10

1.25

0.125

0.02

0.01

8.2

12.5

50

160

1

13.4

0.043

0.2

5.0

5.0

21.5

46.4

215.0

110

60

1

100

3

133

100

1,000

1,000

1,000

1,000

1,000

1,000

1,000

1,000

100

1,000

1,000

100

100

1,000

10

10

100

100

1,000

1,000

1,000

1,000

1,000

10

10

1,000

1,000

1,000

1,000

1,000

1,000

100

1,000

1,000

1,000

1 0

- 7

0.00075

0.00125

0.25

0.00125

0.1

0.01

0.1

0.02

0.001

0.0125

0.0085

0.1

0.1

0.00125

0.0125

0.002

0.0001

0.082

0.0125

0.05

0.16

0.001

0.0134

0.0043

0.02

0.005

0.005

0.0215

0.0464

0.215

0.11

0.6

0.001

0.1

0.003

1,000 0.133

Suggested no-adverse-effect

level from H20, μg/liter

assumption

1 2

87.5

700

7 x 10 4

5.25

8.75

1,750.0

8.75

700.0

70.0

700.0

140.0

7

87.5

59.5

700.0

700.0

8.75

87.5

14.0

0.7

574

87.5

350

1,120

7

93.8

30

140

35

35

150

325

1,505

770

4,200

7

800

21

931

4.4

35.0

3.5 x 10 5

0.26

0.44

87.5

0.44

35.0

3.5

35.0

7.0

0.35

4.4

2.98

35.0

35.0

0.44

4.4

0.7

0.035

28.7

4.4

17.5

56.0

0.35

4.7

1.5

7.0

1.75

1.75

7.5

16.0

75.25

38.5

210.0

0.35

35.0

1.05

46.5

aUncertainty factor—the factor of 10 was used where good chronic human exposure data was available and supported by chronic oral toxicity data in other species,

the factor of 100 was used where good chronic oral toxicity data were available in some animal species, and the factor 1,000 was used with limited chronic toxicity data.

bAcceptable Daily lntake (ADl)—Maximum dose producing no observed adverse effect divided by the uncertainty factor.

cAssumptions Average weight of human adult = 70 kg, Average daily intake of water for man = 2 liters

1 20% of total ADI assignment to water, 80% from other sources.

2. 1% of total ADI assigned to water; 99% from other sources

dDetected but not quantified

SOURCE National Academy of Sciences, National Research Council, Drinking Water and Health (Washington, D C US Government Printing Office, 1977)
—

Table 26.—Organic Pesticides and Other Organic

Contaminants Found in Drinking Water, With

Insufficient Data on Chronic Toxicity to Calculate

an Acceptable Daily Intake

Highest concentration in

Concentration finished water, μg/liter

Acetaldehyde . . ~, . . . . . . . .

- – 0.1

Acroleina . . . . . . . . . . . . .

Bromobenzene . . . . . . . . . . . . detected

b

Bromoform ... . . . . . . . . . . . . . detected

Carbon disulfide . . . . . . . . . . . . detected

Chloral . . . . . . . . . . . . . . 5.0

Chlorobenzene . . . . . . . . . . . 5.6

Cyanogen chloride . . . . . . . . . . 0.1

1, 2-Dichloroethane . . . . . . . . . 21.0

2, 4-Dichlorophenol . . . . . . . . . 36.0

2, 4-Dimethylphenol . . . . . . . . . detected

e-Caprolactam . . . . . . . . . detected

Hexachloroethane. . . . . . . . . . . 4.4

o-Methoxyphenol . . . . . . . . . detected

Methyl chloride . . . . . . . . . . . . detected

Methylene chloride . . . . . . 7,0

Phenylacetic acid . . . . . . . . . . 4.0

Phthalic anhydride . . . . . . . detected

Propylbenzene ... . . . . . . . . . <5.0

t-Butyl alcohol . . . . . . . . . . . 0.01

Tetrachloroethane. . . . . . . 4,0

Tetrachloroethylene . . . . . . . . . <5.0

Toluene . . . . . . . . . . . . . . . . . . 11.0

Trichlorobenzene . . . . . . . . . . . detected

1, 1, 2-Trichloroethane . . . . . . . 1,0

Nicotine . . . . . . . . . . . . . . . . . . . 3.0

Methomyla . . . . . . . . . . . . . . .

Cyanazine . . . . . . . . . . . . . . . . . detected

Xylene ... . . . . . . . . . . . . . . . . <5.0

aNot detected in finished drinking water

bDetected detected but not quantified

SOURCE” National Academy of Sciences, National Research Council, Drinking

Water and Health (Washington, D C U S Government Printing Office,

1 977)

Ch. IV—Water Quality ● 101

—

health cannot be answered with certainty at

this time. The key issue is whether or not certain organic chemicals found in very low concentrations can cause or increase the rate of

cancer development in man. Even though

several of these chemicals have demonstrated

carcinogenicity in laboratory animals, the extrapolation of such results to man remains difficult for a number of reasons.

Among the reasons for uncertainty was the

difference in dosage: the doses at which tests

are conducted are many times greater than the

concentrations of the same chemicals found in

drinking water. Therefore, risk at low levels of

exposure is derived, out of necessity, by extrapolation from high doses. “There is no real

hard evidence, “ it was said, “that low-level exposure to the same chemical produces cancer, ”

The 1977 report summarized NAS’s position

on pesticide use as follows:

Demonstration that a pollutant is carcinogenic, and application of nonthreshold risk

estimates to it, do not imply that its use must

be prohibited. Such a prescription might itself

give rise to even greater risks to health or

other disadvantages. In some cases, a net risk

must be estimated, and society must attempt

to use the pollutant in such a way as to

minimize risk and maximize benefit.

The

DATA COLLECTION

Water-Quality Monitoring The stations included in the NASQAN network were established to measure the amount

only coherent nationwide information of surface water flowing out of a watershed.

on water quality is provided by a monitoring

system established by USGS in 1975. The National Stream Quality Accounting Network

(NASQAN) is an assemblage of monitoring stations located in different river basins and subbasins, The size of the network is increasing

and now numbers over 500 stations, of which

approximately half are in the Western United

States. The same data have been collected on

the same pollutants since the inception of the

network.

For this reason, they are not necessarily located

where water is used. In some cases, the watersheds which the stations were established to

monitor are located upstream from major pollution sources, In other cases, the station may

be located substantially downstream of such

sources, For those pollutants that do not degrade or otherwise change in the water, downstream monitoring locations may be adequate.

However, some water pollution problems are

quite localized. For example, the depletion of
102 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

oxygen in a stream near the point where municipal sewage or agricultural organic wastes

enter may produce serious problems near the

point of discharge and be undetectable by the

time the river reaches a NASQAN station.

Moreover, NASQAN stations do not measure

all pollutants. Most toxic organic chemicals,

such as those used as pesticides, are not measured. In many cases, monitoring equipment

may not be able to measure low concentrations

of pollutants which nonetheless may have a significant effect on water quality and long-term

implications for human and animal health.

Additional information on water quality is

collected by State water pollution authorities.

The usefulness of this information, however,

is limited because of variations in State programs and monitoring procedures and because

the data often cannot be easily obtained. One

useful source of State-generated information

is the set of reports that State authorities are

required to submit to EPA every 2 years under

section 305(b) of the Clean Water Act.

No systematic, comprehensive monitoring of

ground water quality exists, Federal legislation

adopted subsequent to the Clean Water Act has

——

addressed ground water contamination from

selected sources, principally hazardous waste

sites. But this legislation (the Resource Conservation and Recovery Act, or RCRA, and

the Comprehensive Environmental Response,

Compensation, and Liability Act, “Superfund”

program) lacks clearly stated ground waterquality objectives.

The Safe Drinking Water Act contains a provision that allows the Federal Government to

attempt to prevent pollution of specific aquifers

designated as the sole source of drinking water

supplies. Since its passage in 1975, nine aquifers have been designated as sole-source aquifers. Approximately 12 additional aquifers are

in various stages of investigation for inclusion,

In 1979, EPA began to integrate its various

legislative authorities for ground water quality into a coherent ground-water protection

strategy. In a draft published in 1979, the Agency has proposed water-quality goals for ground

water and alternative means of achieving those

goals. The success with which these goals are

met is clearly related to the effectiveness of

a ground-water quality-monitoring program,

which has yet to be established,

To evaluate the relationship between water

quality and agriculture in the Western United

States, it is necessary to consider: 1) the effects

of agricultural uses on water quality for other

uses, and 2) the effects of water quality on various agricultural uses. In some cases, these are

linked in that an agricultural water use may

create a quality problem that affects succeeding

users, including agricultural users. In other

cases, water-quality changes that are deleterious to agriculture may result from nonagricultural water uses or simply from the processes

that determine natural water quality.

The types of possible water pollution are

varied and can arise from different uses, They

can be summarized in eight general categories:

1.

2.

3,

4.

5.

6.

7.

8.

municipal sewage and other oxygendemanding wastes,

infectious agents,

synthetic organic chemicals,

inorganic chemicals and mineral substances,

sediments,

plant nutrients,

radioactive substances, and

heat.

The highest quality water required in agriculture is for domestic farm consumption.

Almost all of the water used in this way is taken

from water wells, The quality of this water is

not routinely monitored, nor is it subject to any

routine treatment prior to use, as is the case
.

— — —

Ch. IV—Water Qualify ● 103

—

with municipal domestic water supplies. The

quality of this water source is particularly susceptible to degradation because of the many

potential sources of contaminants in the farm

environment.

Water that is safe for human consumption

can also be used by livestock, but some stock

can tolerate water of a somewhat poorer quality. It is suspected that many animal diseases

can be transmitted by contaminated water.

Water for livestock use can either be polluted

by natural sources, such as a high natural

mineral content of the water or a deficiency

of some necessary mineral, by algae “blooms”

associated with the discharge of agricultural

fertilizers into the water, or by the presence of

diseased animals.

The quality of water used in irrigation is very

important. Also important is the way in which

this irrigation water is applied to the soil and

the characteristics of the soil itself. As some

water applied in irrigation is lost to evapotranspiration during the growth of plants, the salts

contained in that water are left behind in the

soil. If this situation is not eventually corrected

by the application of additional water to leach

the salts out of the soil and return them to the

river, this salt buildup will ultimately restrict

agricultural productivity. The return flows

from this leaching process raise public health

implications for downstream drinking-water

users.

Present knowledge of water constituents and

associated tolerance limits for various users is

far from complete. Some tolerance levels are

available, however, for evaluating the suitabili1

2,

3,

CHAPTER IV

American Heart Association, “Sodium Rest ri(; t [;[i Diets: 500 rng, ’ 1965

Arnlijo, C, P., an(i Coulson, A. H., “Epidemi -

oiogj of” Stoma[; h Cancer in Chile—The Role

of N’it rogen Fertilizer, ]ni, ]. Epidenziol.

4:301-309, 1975.

13el]an, J. R., 1 rej’, N. S., Kilgore, W. W., Kirnura, K., Suski n(l, R., Vostai, J. J., an(i Wheatcr,

R, Ii., “The I Ieaith Effects of ‘Agent Orange’

ty of water for particular uses. Increased research efforts would contribute to improved information on water-quality aspects of agricultural water use.

The possibility of supplementing irrigation

water supplies in some areas with municipal

and industrial wastewater is receiving increased attention. The suitability of such water

for agriculture depends on its level of contamination and the type of treatment it receives. The most serious reservations concerning this practice have to do with viruses and

heavy metals, which are particularly difficult

to remove by existing water treatment. There

is concern that viruses may remain viable in

the water or the soil for long periods of time

and pose a significant health threat to both

humans and animals.

Water contamination resulting from agricultural practices involves many natural and

chemical nonpoint sources of pollution that are

particularly difficult to detect and treat. The

exact effect of any single practice will be largely determined by the nature of the substance

introduced into the water, the concentration

at which it is introduced, and the natural

capacity of the soil-water system to deal with

that substance, Effects may range from increased sedimentation to complicated chemical reactions from synthetic agricultural pesticides that are suspected of causing serious

human health problems ranging from cancer

to nervous disorders. In all cases, more efficient management of potential sources of water

pollution from agriculture will do much to decrease the severity of the impacts.

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5.

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— — — . —

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25-160 0 - 8 : QIJ 3
— .

Affecting

Institutions

Western Agricultural

Water Use
— .

Page

Western Water Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Water Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Western Water Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

State Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Federal Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Interstate and International Agreements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Implications for Sustainable Western Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Socioeconomic Factors Affecting Western Water Institutions . . . . . . . . . . . . . . . . . . . . . . . 125

Demographics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Rural Economics and Western Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Competition for Western Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

The Economics of Western Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

A Market for Water... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Water Economics in a Nonmarket Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Economic Efficiency and the Adoption of Water-Related Agricultural Technology . . . 141

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

List of Tables

Table No. Page

27. A Summary of Western Water Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

28. Indian Reservations and Rural Populations by Region and State . . . . . . . . . . . . . . . . . 119

29. Status of Settlement of Western Indian Claims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

30. Percentage Increases in Population for the 17 Western States

and United States, 1930-80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

31. Population and Employment Change by Region and State . . . . . . . . . . . . . . . . . . . . . . . 129

32. Total and Farm Population of the United States: 1920-81 . . . . . . . . . . . . . . . . . . . . . . . 130

33. Projections of Changes in Total Cropland and Irrigated Farmland

by State, 1975-2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

34. Rate of Change in Water Use as Percentage of Total Water Use, Municipal and

Industrial. Irrigation Purpose in Selected States... . ................,,.,,,,,.. 133

35. Cost per Acre-Foot of Water to Pump at Alternative Depths, Given

Selected Natural Gas and Electricity Prices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

List of Figures

Figure No. Page

26. Federal, State, and Local Spending for Water Resources, 1960-82 . . . . . . . . . . . . . . . . 112

27. Surface-Water Law Systems in the Western States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

28. Ground-Water Law Systems in the Western States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

29. Population Rate of Change of the IT Western States Compared

to the U.S. Population, Rate of Change, 1930-80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

30. United States: Census Regions and Divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Chapter V

Institutions Affecting Western

Agricultural Water Use

Distribution and use of Western water resources for sustainable agriculture are subscribed by two institutional forces: first, water

laws that establish rights and duties with respect to the use of water and, second, in recent

years, economic institutions that allow water

to be transferred between users and uses.

These institutions and their associated rules influence the adoption of water-related technologies and effective water management for sustainable Western agriculture, The Western

agricultural water user is, at best, moderately

uncertain about water use because it is unclear

how these rules might change as demands increase,

This chapter first describes the major elements of western water law as they affect

water use in agriculture, In light of growing

demands on existing supplies and few opportunities to acquire new inexpensive water,

water economics is receiving increased interest

as a vehicle for reallocating water among competing demands. The chapter next highlights

some of the factors contributing to increased

demand for Western water and then examines

factors affecting the feasibility of water markets

and the impact of economics on the adoption

of water-related technologies for sustainable

Western agriculture.

History

In the early days of the United States, when

Western lands were owned in a proprietary

capacity by the United States, a precondition

to settlement and development of the watersport West was a secure water supply. Farmers

and soiree miners diverted water through networks of small river dams and canals for use

on distant lands. Other settlers and miners

located along streambanks claimed rights to

water in those streams. In early conflicts, the

courts generally followed local rules and

custom and ruled against riverbank (riparian)

settlers on the grounds that they did not legally meet the riparian doctrine’s fundamental requirement, ownership of the land.

Perhaps more important, water was already

being used consumptively far away from the

stream to meet the needs of farming, mining,

and other purposes in this arid/semiarid region,

In contrast to the humid and water-abundant

Eastern United States, it became increasingly

important in the West to ensure that upstream

diversions would not deplete supplies on which

downstream investments depended. Thus began an early judicial recognition of the right

of the first user [or appropriator) of surface

water in western lands to have the superior

right to that water. “First in time, first in right”

became the local rule.

Gradually, Federal programs became directly

involved in shaping the character of Western

agriculture and water use. Two Federal laws

had particular impact on early Western agricultural and water development. First, the

Desert Land Act of 1877 severed water rights

from the public land and granted each State

the right to adopt its own system of water law

to govern the appropriation of nonnavigable

waters. In the act, Congress also recognized

that farmers in the arid/semiarid western lands

could not operate successfully on the 160-acre

parcels of land provided by the Homestead Act

of 1862 and so granted full title to 640 acres

109
110 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Box E.—John Wesley Powell’s “Blueprint for a Dryland Democracy”

John Wesley Powell, chronicler of American Indian languages, explorer of the Colorado River,

and one of the most prominent Government scientists of his age, knew the West intimately. He

watched with dismay as Western settlement followed Eastern models. In 1878, he presented a revolutionary plan to the United States Congress. It proposed to tailor agricultural development to the

unique features of these dry lands.

As Wallace Stegner, a major American historian described it, Powell’s plan had several important provisions regarding the size and shape of homesteads and their ownership. Stegner wrote:

Water was the true wealth in a dry land; without it land is worthless or nearly so. And if you

control the water, you control the land that depends on it. In that fact alone was the ominous threat

of land and water monopolies. To prevent this-or to stop it for it was already beginning to happen,

Powell made two proposals. One was that each pasturage farm should have within its 2560 acres

twenty acres of irrigable land with a water right that was inseparable from the land. , . . Instead

of rectangular parcels, therefore, Powell proposed surveys based on the topography, letting farms

be as irregular as they had to be to give everyone a water frontage and a patch of irrigable soil.

The second part of Powell’s proposal suggested that national surveys, conducted by a central Government scientific agency or settlers themselves, would choose irrigation or “pasturage” for their

regions. Stegner wrote that “In either case, a homesteader would have a guaranteed water supply.”

Powell’s proposals were debated in Congress in 1878 and 1879. They were defeated by powerful Western delegations, Powell’s scientific enemies, and the special interests of the day. Powell

went on to suggest other far-reaching plans for the development of the arid West. But the Nation

never fully used the insights of this man who understood “the unity of drouth.”

SOURCE: Wallace Stegner, Beyond the Hundredth Meridian: John Weseley Powell & the Second Opening of the West (Lincoln, Nebr.: University of Nebraska Press,

of land after 5 years of residency if a portion

of the land were developed for irrigation within

a specified period. Second, the Carey Act of

1894 granted 1 million acres of public land to

each State containing arid lands on condition

that the State provide for the necessary reclamation.

Under these laws Congress deferred to Western State appropriation doctrines for local nor)-

navigable water use. Since then, Federal waterrelated agencies have generally been required

to comply with State laws in the appropriation

of such water. *

Water Projects

The progress of water development in the

Western United States has had a fundamental

impact on the development of Western agricul-

. —

“See, for example, the Federal Reclamation Act of 1902, which

requires the Secretary of the interior to secure project waters

in accordance with local law.

ture and on the kinds of water-related technologies developed and adopted. As more individuals became involved, mutual water companies or water cooperatives were formed to

reduce conflict and ensure a fair distribution

of water. Mutual irrigation companies frequently became formal corporate entities under

State charters, with stock being issued to their

members as evidence of proportionate voting

rights in the election of company directors.

Many other groups elected officers on the same

voting basis as in formal corporations but operated as associations rather than as formally

registered corporations. In some areas largescale irrigation projects were organized and

supported by foreign capital, primarily from

the British (24). Today, many of the Western

mutual irrigation companies are still significant water institutions, some having been

transformed into major water management and

power-generating organizations.

As the need for water increased, the trend

in water-management development was for an
Ch. V—Institutions Affecting Western Agricultural Water Use ● 111

— — .

increasing government role. Early State legislation authorized the creation of water supply

and irrigation districts and provided formal

organization and power to the districts to raise

revenue for constructing water-conservation

facilities such as dams, reservoirs, canals, and

diversion structures. A further shift occurred

with the passage of the Federal Reclamation

Act of 1902 (Public Law 57-161). The features

of large-scale construction projects called for

a strong role by the Federal Government in particular, for substantial financial resources,

technical expertise, and a geographic perspective convenient for interstate river basins,

The 1902 Act provided for Federal subsidies

to irrigators through a number of activities.

First, it set up a revolving fund for irrigation

development from moneys raised through the

sale of public lands, Funds were to be used in

constructing storage and power dams and for

canal systems required for irrigation, Second,

settlers were to receive their lands free in much

the same way as under the Homestead Act (a

5-year residency requirement) but were to repay the costs of structures built by the Government within 10 years. Gradually, Federal subsidies were further extended to irrigation farmers in the form of interest-free loans for capital

facilities, longer repayment periods, low interest rates, contributions to irrigation construction costs by other beneficiaries (especially

power users), and a repayment formula that attempted to consider the irrigator’s ability to

pay.

The politics of these and other federally subsidized projects has been called “distributive,”

reflecting a political process whereby each element in an omnibus package is carefully designed to provide local benefits to a variety of

community, user, and political interests (17).

Congressional vote-trading determined who

would get the initial Federal projects. This distributive process involved both upstream and

downstream States in the arid/semiarid West.

Growth in some areas was made possible in

part through the consent of upstream users

who, under less growth pressure at the time,

believed they would eventually receive Federal assistance for water development (15). The

apparent cost-free benefits to local communities provided incentives for sponsorship by the

principal local political interests, and actual

costs were distributed among general taxpayers. Clear standards for judging the long-term

desirability of these projects based on costs and

benefits to the Nation, were largely absent in

these early decisions (18).

“Principles, Standards, and Procedures” (replaced in 1983 by the new “Economic and Environmental Principles and Guidelines”) were

developed pursuant to the 1965 Water Resources Planning Act to guide the planning and

design of projects. The application of these criteria has led to conclusions that many projects

are uneconomic and unjustified, Federal financing arrangements for water projects have

been under attack particularly regarding the

planning, design, and actual construction of

projects whose costs are not adequately recovered (31). The fiscal criticism focuses on the

overall costs to Government, including the

costs of Government borrowing, and whether

this should remain a priority in light of other

Government concerns.

Reforms of existing Federal water-project repayment laws and practices that include more

equitable cost-sharing arrangements and

greater cost recovery from water users are

underway and are likely to continue over the

next several years (32). From its peak in 1965,

Federal spending for water projects has generally declined (see fig. 26). Moreover, expenditures for water resources appear to be

shifting away from massive new construction

projects and toward rehabilitation and more

efficient management of existing public works

(27).
112 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 26.—Federal, State, and Local Spending for

Water Resources, 1960-82a

aActual State and local data for 1980-82 not avaiIable.

SOURCE Congressional Budget Office from data supplied by the Congressional Research Service and the U.S. Department of Commerce,

Bureau of the Census, U.S. Congressional Budget Off Ice. Public

Works Infrastructure Policy Considerations for the 1980’s

(Washington, D C U S Government Printing Office, 1983)

Water’s special nature as both a natural resource and an essential social good has always

made it subject to some public regulation to

protect public interests. Until laws were developed, settlement of disputes over water

rights was left to private means, often vicious

and brutal. Early on, a clear interest developed

to channel private grievances to public institutions, thereby bringing some order and equity

to the process of water use and distribution.

The major State and Federal law doctrines

that have developed to regulate water are

fundamental in guiding decisionmaking on

water distribution and use in the arid/semiarid

West. They define the extent of a water user’s

rights as well as the extent of duties or constraints on those rights. The doctrines are key

factors influencing decisions about the adoption of water-related technologies for sustainable agriculture.

The concept of priority in accordance with

the date that use began gave birth to the term

“prior appropriation” to describe the most

common water-use system in the Western

States. The fundamental principles established

under this arrangement have been followed

since its recognition by early courts. They are:

1.

2.

3.

that water in its natural course is the property of the public and is not subject to

private ownership;

that a vested right to use the water may

be acquired by appropriation and application to beneficial use;

that the person first in time is first in right;

and
Ch. V—Institutions Affecting Western Agricultural Water Use . 113

—

4. that beneficial use is the basis, measure,

and limit of the right (6).

This doctrine creates the right of private use

of a public resource under certain conditions

where the use has been declared to be a public

one. Generally, a use is public when it is applied to a beneficial purpose, defined initially

in State constitutions and statutes to be domestic, municipal, stock watering, irrigation, and

certain industrial and power uses. More recently, it has also been defined in a few States (e.g.,

Colorado and Montana) to include instream

flow (see app. C). Some State laws give a preference to one sector of use over another. Historically, in most Western States, strong rural

representation has ensured agriculture a high

position as a beneficial user.

An acquired water right in the Western

States has two legal characteristics. First, the

right is a real property right to use the resource,

a right which if defined can be sold, bequeathed, or otherwise transferred so long as

approved by the State water authority, a necessary condition to protect other appropriators.

Second, it is a right to be exercised only when

the water authorized for diversion under the

right is available and applied to a “beneficial

use. ” The water applied must also be “reasonable” for that use. If the rightholder cannot put

it to reasonably beneficial use, the water remains a public resource to be passed to other

appropriators, However, if the rightholder can

beneficially use the water, it remains an individual’s personal property while diverted within his/her delivery system and until it is returned back to the natural system (stream or

aquifer).

State Level

States are involved with water regulation

through their implied constitutional powers to

create property rights and to protect and regulate their citizens through their police powers.

State water law regulates use, not ownership,

of water by granting and administering rights

for use contingent on conformity with certain

conceptions of “public interest” as developed

by the political process.

The development of State water-law principles was influenced by early court decisions,

some reinforcing and others frustrating local

custom. Because of its reliance on precedent,

the judicial arena has been slow to reflect contemporary scientific understanding of water as

it operates in a dynamic, interconnected, surface-subsurface system, Western State legislatures and related local water institutions have

had to become increasingly active in attempts

to meet changing needs and resolve conflicts

over use. While early legal doctrines remain the

backbone of current State water law, innovative experiments also are underway in some

States to adapt these principles to be more responsive to the increasing demands on limited

supplies (discussed in app. C).

Surface and Ground Water Law

Major bodies of water law at the State level

have developed for surface-water instream

sources and ground water. Historically, each

has been treated separately under the law and

generally without regard to natural interconnections existing within the hydrologic cycle.

The point at which water was diverted from

its natural state and brought under control determined the legal classification (26).

The historical development of water law permitted each Western State to formulate solutions that fit local needs. Although each accepted the major concepts of prior appropriation, various State laws developed significant

differences in their substantive and administrative aspects, Some with more humid areas integrated certain riparian rights with prior appropriation doctrine and developed “mixed”

systems. Some “pure” appropriation States that

had rejected the entire regime of riparian rights

still applied some riparian concepts. The riparian doctrine of the water-abundant East was

gradually entirely replaced by the appropriation doctrine in other States. Figure 27 identifies the general system of surface water law

under which each of the 17 Western States operates,

Several States have adopted additional rules

to protect water needs of users within a water-
114 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 27.—Surface-Water Law Systems in

the Western States

Legend

SOURCE G. E Radosevich, Western Water Laws and Irrigation Return Flow,

EPA.600/2-78-180 (Ada, Okla U S Environmental Protection Agency,

1978).

shed or river basin from future shortages

caused by out-of-basin diversions and uses.

These “basin of origin” statutes (see table 27)

have taken a variety of approaches, from those

that authorize inhabitants within the basin to

reclaim water for future needs, to others that

restrict transfers outside the basin to water that

is determined to be surplus.

Ground water rights and legal systems developed more recently in the western States,

owing in part to reliance on surface supplies

for the early settlements and in part to a lack

of knowledge about subsurface supplies and

the technologies to develop them. As knowledge of ground water increased and as subsurface supplies were in greater demand, and

public regulation of withdrawal and use

became more important. For legal purposes,

ground water has commonly been divided into

two classes: 1) underground streams which

flow in known and definite underground channels, and 2) percolating waters which flow

beneath the surface of the earth in no known

or identifiable natural channels. These legal

classes are often at variance with scientific

evidence, since in many areas no natural distinctions actually exist. All ground water is

presumed in law to be percolating water, rather

than an underground stream which would be

considered in law essentially the same as surface water.

For ground water, each Western State

adopted and modified basic surface doctrines

to fit its perceived needs. Four major legal doctrines developed. A few States took the English

view of absolute ownership of ground water

somewhat parallel to the riparian view of surface water–i.e., the owner of the land owned

all of the water within or under it because this

water was deemed to be part of the soil. The

consequence was that a landowner had no liability for any use made of ground water even

though that use might damage others (8). As

it became more evident that ground water

moved in subterranean aquifers and use of, or

interference with, such water could affect other

landowners, this common law rule was later

modified in some States to limit the landowner

to reasonable use.

Other doctrines developed with the growth

in knowledge about the interconnection of

ground and surface waters. Some Western

States adopted the doctrine of correlative rights

whereby each landowner was held to have

rights in a common aquifer in proportion to the

land overlying the aquifer. Many States applied

the appropriation doctrine to ground water, requiring that rights could only be acquired by

withdrawing the water and applying it to a beneficial use. Figure 28 identifies the basic

ground water doctrines used by the 17 Western

States; most States have modified these basic

theories to some extent by legislation (e.g., the

Arizona Ground Water Management Act, 1980

[Ariz. Rev. Stat. (45-512)]).

Recently, challenges to the validity of two

State ground water statutes have raised con-
Table 27.—A Summary of Western Water Law I

8 9 10 11

Water Water

Date of Appurtenance rights quality

priority registry in rights

D O A Strict Original Case

12 13 14

Basin

Forfeiture Drainage o f

of rights a

ruIes on g I n

5 yrs CE & Yes

C L

C

5 yrs <1914 Yes

3 yrs >1914

. . . e C L Yes

(modified)

1 2 3 4

Water Law Doctrines Evidence

Surface Ground Ownership of water

waler water right

P A R.U b Public Permit

P A &R C R People Permit d

PA P A Public S.W. -

decree

G W -

permit

P A P.A State License

P.A & P A People Permit

R

g

P A PA. State Permit

5 6 7

Criteria Preference

Basis of of of use

allocation alIocation (order)

B U B U 1.2.3-4-5

Legal

feature

State

1-ARIZ

2 CAL B &R U B &R U 1 2 - D O A Unlimited Current Case +

post 1914 Statute

B U B U 1-2 over 5 S W None Original Case

1st step (compuG W terized)

3-COLO

D O A

4.IDA B.U 1 cfs/50 1 -2 D O A Unlimited Current Case 5 yrs f C L

acres (Limited)

B U 1 to 2 1-2-5-6-3 DOA Case +

acre-ft/ Statute

acre

B.U 1 miners None D O A Original Case

feet per (Limited)

acre —

B U 1 cfs/70 1 2 over 5 D O A Case

acres or 3

acre ft/

5.KAN 3 yrs C L

6 MONT . . e C E

PA & R . U

b Publi c Permit

R

g

7.NEB 3 yrs C E Yes

8-NEV

acre

P A P.A Public Permit B U Conditions None D O A Original Case

P A P A Public Permit

5 yrs C.L.

& needs

B U BU & None D O A Original – Case

good agr

practices —

B U 1 cfs/80 1-2 & 5-6 D B U Case

acres

B.U B U. None D O A Stric t Current Case

7 yrs + 1 C L

yr after

notice

9-N M

1O-N D P A P.A. Public Permit 3 yrs R.D.

11 .OKLA 7 yrs R.D Yes

12-ORE

PA & P.A. -- Permit d

R.g

P A. & P A ‘

— Public Permit

R

g

B U. - B U“-

1-2-4 -- D.O.A Strict Original Case 5 yrs C L.

13-S D P.A & P A People License

R

g

B U. 1 Cfs/70 1-. D.O.A. Original Case

acre or 3

acre-ft/acre

3 yrs C.L

14-TEX PA &

R

g

P A

A O State Permit d B U B U 1-5-2-4- D B U Current Case 10 yrs C.L Yes

3-7-6

15.UTAH P A Public Permit B U Nature of 1-2 D O.A. Current Case

use

5 yrs C E

PA &

R

g

P A Public Permit —

B U Reasonably None DBU & Current Case - 5 yrs ‘– C E

necessary D O A. for (compu-

& B.U permits terized)

B U. 1 cfs/70 1-5 D O.A. Strict Original Case 5 yrs “- “Undecided

acres

16.WASH

17 WYO P A P.A State Permit

KEY

A O —absolute ownership, B U —beneficial use, B &R U —beneficial and reasonable use, C E — aAll States recognize loss by abandonment

common enemy C L —civil law, C R —corrective rights D O A —date of application, D B U —date Lack comprehensive ground water laws.

of beneficial use G W —ground water, P A — prior appropriation R — riparian, R D —reasonable c ~C - E - flood waters, C L . natural flows

discharge R U — reasonable use S W —surface water -Different types, not for 1914 rights, riparlan rights, and percolation ground water

Column 7 1 – domestic and municipal 2—agricultural (irrigation), 3—power, 4—mining, eTen years IS evidence of abandonment

5— manufacturinq and Industrial 6—recreation 7— navigation In mining districts 4 over 2 and 5

Column 9 Original —initial filing recorded Current —user must notify agency of name use place gAll new water by prior appropriation

etc transfers unlimited

SOURCE Adapted from: G E Radosevich, Western Water Laws and Irrigation Return Flow, EPA-600/2-7&180 (Ada, Okla.: U.S. Environmental Protection Agency, 1978)
116 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 28.—Ground-Water Law Systems in

the Western States

Appropriation Correlative rights

aOklahoma has many characteristics that also place it in the correlative rights

category

SOURCE: Adapted from G. E. Radosevich, Western Water Laws and Irrigation

Return How, EPA-600/2-78-180 (Ada, Okla.: U.S. Environmental Protec.

tion Agency, 1978).

cern about some of the traditional precepts of

Western water law, In particular, the U.S. Supreme Court in Sporhase, et al., v. Nebraska

(25), and the U.S. District Court in El Paso v.

Reynolds (10), decisions addressed the legal

grounds of two States, Nebraska and New Mexico, to protect their scarce water supplies.

While noting a State’s public interest and equity concerns over water, these courts declared

water an “article of commerce” and held unconstitutional State antiexport statutes that

placed an undue burden on interstate commerce. Because their scope or potential impact

is unclear, these cases have increased the confusion about a Western State’s proper role in

protecting and conserving vital water resources for its own citizens in times of severe

shortage. Conceivably, the impacts are regionwide (29]. Several other Western States have

laws similar to that declared unconstitutional

in the Sporhase, et al., v. Nebraska case.

Water Quality Under TraditionaI

Doctrines

Water-quality considerations are noticeably

absent in a majority of the surface and ground

water doctrines of the Western States. The one

exception is California, which has a statute

making water quality a specific element of a

water right. A California user can make the

same demands on an agency to protect an interest in water quality as that in water quantity entitled under the water right (24).

An implied right of water quality exists under

the doctrine of prior appropriation. In theory,

water-right holders should be entitled to the

quality of water existing at the time of its appropriation. In practice, however, if an individual believes a water right is being impaired

because of upstream pollution, the only recourse in most cases will likely be a lawsuit

based on common law doctrines of nuisance

and trespass. Only a few courts have protected

irrigation users from upstream polluters, and

these cases have usually involved extreme instances of water degradation. Most of the cases

relating to such pollution occurred in the early

1900’s (24).

The extent to which an individual State

water-right holder might be able to revive either

appropriation or common law doctrines for

water-quality purposes is questionable. Unless

strict controls exist, water-quality deterioration

will probably increase as development and

water use intensify in the West. Some States

more than others may experience severe waterquality problems and thus threaten an individual user’s right.

Administration of Western Water Rights

In most of the West, rights to use water are

regulated and administered on a comprehensive basis. Table 27 summarizes the adminis-
Ch. V—Institutions Affecting Western Agricultural Water Use . 117

trative approaches developed by each of the 17

Western States to oversee the system of water

rights, Commonly, a State officer, often designated the “State Engineer, ” holds one of the

most powerful positions in State-level water institutions. This officer keeps records of water

use, receives and approves applications for

new water uses, appoints river commissioners

or water masters to supervise the distribution

of water in accordance with water rights of

record, and institutes court actions to determine and adjudicate both surface and ground

water rights.

The prominent approach used for providing

evidence of a Western water right is the permit system (table 27, column 4). In some States,

the final water right may be called a license or

certificate. A few States have different classes

of permits to enhance their ability to allocate

and regulate the use of water among competing

interests.

In the West, most States have well-established procedures governing the transfer of

water rights (7). A water user or a purchaser

of a water right generally is entitled to change

the point of diversion, place, and nature of use

of the right. However, as a procedural matter,

before such a change maybe made, the owner

of the right must file a change application with

the State water-rights administrator. The purpose of the change application is to give notice

to other water users on the system of the

changes proposed and to allow the administrator to determine whether or not the change can

be approved without impairing other existing

rights on the same watercourse. The general

rule in most States is that an appropriator is

entitled to rely on stream conditions substantially as they were when that individual made

an appropriation, and any change that is proposed cannot adversely affect other existing

water rights (7). The question of impairment

usually arises in connection with return flow.

This is particularly true with respect to irrigation uses where it is common for some of the

irrigation water to return to the watercourse

as return flow or seepage. If this is the case,

and the return flow makes up a portion of the

downstream water rights, the upstream irrigator is not allowed to diminish that return

flow by changing his/her water right. However,

subject to the caveat that a proposed change

cannot impair other water rights, most States

have adopted a fairly liberal policy with respect

to proposed changes.

An unrestricted policy with respect to water

transfers has caused a few States to reevaluate

their historic practices in this area. For example, the Wyoming Legislature has provided that

when considering a change application the

State Engineer may consider: 1) the economic

loss to the community and State as a result of

the discontinued use, 2) the extent that such

economic loss would be offset by the new use,

and 3) whether there may be another source

of water available to satisfy the new use. These

criteria supplement the traditional consideration of whether or not there would be impairment of other rights. This legislation thus

allows for at least some modest evaluation of

the public interest in determining whether the

proposed change should be approved. Montana has taken a more restrictive step in an effort to protect large agricultural rights in that

State. The Montana Water Code prohibits a

transfer of an irrigation right to an industrial

use if the quantity of water involved exceeds

15 cubic feet per second. This provision appears to have been designed to preserve the

agricultural industry in that State (7).

Administration of Western water rights has

become particularly complicated regarding allocation of those rights. In practice, water is

allocated not only on the basis of traditional

water law doctrines that have developed for

naturally flowing and underground water but

also on the basis of contractual arrangements

between water districts and water supply agencies. A Federal or State agency may have constructed a dam for water storage, with entitlement to this water being defined by agreement

with a water district. Thus, the specific amount

delivered to an individual farmer may be

unique to the given water supply system and

not be defined entirely by strict application of

a priority-of-use system. For example, an individual farmer may receive water defined by

combined flow and storage rights and also have
118 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

access to water in an underground aquifer.

Many irrigation farmers in the West have all

three types of water. Identifying what a particular user can get, when, and how becomes

complicated. In addition, in some States permits are issued for single purposes, so consolidated records may not be available to identify

the amounts allocated to and uses approved for

a particular individual.

Owing to lack of information, ineffective

monitoring, and disagreement on the meaning

of the standard, the doctrine of reasonable

beneficial use has not proven to be a significant constraint on water use. The definition

of reasonable use depends on the availability

of water, methods of diversion, and purpose

of use, and is subject to uncertainty until the

specific facts and circumstances are examined.

More fundamental to influencing adoption

of “water-saving” technology for Western

agriculture is the requirement of use as the

basis of a water right under the doctrine of

prior appropriation. This concept may discourage water conservation because it emphasizes

either using the full allocation of water or losing the right to the unused portion. It is frequently argued that those who operate more

efficiently and thus save water or who salvage

water that would otherwise go to “waste” have

no assurance that they will be the beneficiaries

of such socially responsible conduct (18).

Federal LeveI

Constitutional authority exists for Federal

water control and regulation through the commerce, property, and general welfare clauses

Box F.-” Today’s Decisions On Water Will Shape Future’'

The following was excerpted from an article by W. W. Lessley, chief water judge for Montana,

who retired at the end of 1982 after 33 years on the bench:

Three great rivers flow through the state--The Yellowstone, the Clark Fork and the Missouri.

Because of this fact, we are truly the Treasure State and seldom face loss of water; but now new

forces move toward our water. The great need of sister states and those states farther to the south

of us for our water is a threat to our complacency concerning this resource. The possibility of Federal

concern and even intervention gives us pause.

If we were asked today by any court or administrative body to show the amount of water we

have and the beneficial use we make of it and our great need for it, we could not do those simple

things.

The reasons for this are many. Approximately 76 percent of our water and water rights are what

we call “use rights.” There era no records anywhere except the use of these rights over a great number

of years. Many of them rest in the far territorial and early history of our state, and the memories

of those on which we rely are now gone. The rest of the percentage is divided between appropriated

rights and decreed rights. The appropriated rights, in many instances, are faulty in record or cannot be found in our courthouse records. The decreed rights are uncertain because some water users

were never informed when judicial action was in process and the inadequacy of the handling of

the tidings.

Now we face the future with water, but for how long? We have strength. We are at the headwaiters. Every rancher knows [w]hat that means even on a simple irrigation ditch, let alone on the

great Missouri.

But we have weaknesses. We have great expanse of territory but few people and few representatives in the Halls of Congress. The lower basin states have many people and that means many

senators and representatives and clout in the Congress!

The future lies ahead. Those who can only see the water we now have and are smug about our

water really don’t think of these things,

SOURCE: Bozeman Daily Chronical Centennial Edition, Mar. 30, 1983.
Ch. V—Institutions Affecting Western Agricultural Water Use ● 119

of the Constitution. The Federal Government

is involved directly in water issues in the

Western United States through the Federal doctrine of reserved water rights, water quality and

environmental protection legislation, and interstate and international compacts.

The Doctrine of Reserved Water Rights

Under the doctrine of reserved water rights,

the Federal Government acts as public trustee

to ensure adequate water supplies to fulfill the

purposes of national parks, forests, Indian

reservations, and other Federal lands. Water

rights become “reserved” by implication whenever Federal land is withdrawn from the public

domain and reserved for some specific use or

purpose: It is now generally settled that when

a Federal reservation occurs, enough unappropriated water is reserved to accomplish in

a reasonable manner the present and future

purposes for which Congress made the reservation [Winters v. United States, 207 U.S. 565

(1908), commonly known as the “Winters” doctrine]. The water so reserved must come from

the watercourses arising on or flowing across

Table 28.—lndian Reservations and

the Federal lands set aside for the reservation.

Federal reserved water rights are vested as of

the date of the reservation, whether or not the

water is actually put to use. These rights are

superior to the rights of those acquired after

the reservation date.

Perhaps the most significant of the reserved

water rights, for purposes of Western agriculture, are those held by Western Indian tribes.

Approximately 400,000 American Indians live

on over 200 reservations in the West (table 28).

Their situation is hardly distinguishable from

that of other rural poor, except for one important difference: the unique status of the Federal

reservation.

In recent years, attention has been drawn to

quantification of these rights as non-Indian

development has expanded in the West and

pressures have increased on existing supplies.

Opinions differ about whether quantification

is desirable for Indian rightholders. On the one

hand, these rights include those for future

needs and opportunities; it may be unreasonable to require that such needs be quantified,

Rural Populations by Region and State

Rural population

Number of Total Number of Percent of total Mean income

Regions reservations Modulation acres population (household) , . .

California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 6,824 502,712.68 22.7 $7,123

Intermountain:

Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4,849

Montana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 24,137

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2,718

Washington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 18,238

Southwest:

Arizona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

New Mexico . . . . . . . . . . . . . . . . . . . . . . 24

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Northern Plains:

North Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

South Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Southern Plains:

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Nebraska. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Texas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

173,412

2,144

4,886

30,125

1,961

16,735

29,119

4,435

3,009

2,601

81,264

1,000

NA = data not available

683,505.23

5,870,984.49

821,945.32

2,779,045.40

24,710,019.26

902,897.00

1,171,699.55

3,463,637.50

1,133,730.31

2,143,046.07

5,962,418.35

1,886,556.00

26,476.00

72,672.85

1,644,913.12

4,473.00

NA

80.2

43.3

48.2

82.4

NA

NA

81.7

65.1

86,5

70.5

NA

NA

NA

48,9

15.2

$5,872

$7,191

$7,200

$4,335

NA

$4,617

$4,189

$5,332

$4,556

NA

NA

$5,389

$7,373

SOURCE Finan, et al , 1982 Original source U S Department of Commerce, Federal and State Indian Reservations (Washington, D.C. U.S Government Printing Office,

1974), and 1970 Census of Population Subject Reports American Indians (Washington, D C U.S Government Printing Office, 1973)
120 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

particularly because technological opportunities may change and because the very nature of reserved rights entails some uncertainty. Furthermore, as the result of a 1983 U.S.

Supreme Court decision in Arizona v. California (l), new concerns have been raised that

quantification, once made, may not be changed

at a later date to meet redefined needs because

developers will have relied on the initial quantification in their investment decisons, On the

other hand, some quantification has been urged

by both Indian and non-lndian interests to increase certainty for developers.

The Federal role in these issues is complex,

and many tribes are finding it increasingly difficult to rely on the Federal Government to act

on their behalf. In one role, the Federal Government finances water-storage projects and allocates water supplies from such projects primarily to non-Indians. In another role, the Federal

Government acts as public trustee for Indian

users. Thus, at any one point in time Federal

officials may be representing competing interests: farmers and ranchers v. the Indians. As

a result, the Western Indian community has increasingly perceived that its interests are not

being fairly and fully represented (15, 21).

Indians defend some claims for water that

at present cannot be put to full use. Most of

that water would go to agriculture and, in fact,

the quantification of Indian rights is predicated

on agricultural uses. Legal questions have been

raised whether their water rights are restricted

to agriculture or can be transferred to nonagricultural and non-Indian uses. Most Indian

groups do not have a tradition of, or sufficient

resources to begin, large irrigated farms. These

problems have been exemplified by the Navajo Indian Irrigation Project, where pressure to

quantify water claims preceded clear plans regarding water use (9). In the absence of such

planning, Southwestern Indians have considered several options, including the sale of partial allotments to their municipal, industrial,

and agricultural competitors.

Other claims—owing to the historical uniqueness of the reservations—focus more specifically on present threats to Indian water use and

livelihood from non-Indian development off

the reservation. In several areas of the West,

non-Indian uses of both surface and ground

water off the reservation either have damaged

or threaten to damage Indians on the reservation. The Pyramid Lake Paiutes in Nevada, for

example, sued the State, the Truckee-Carson

Irrigation District, and some 13,000 other water

users for lowering the level of the lake so that

a principal economic activity, fishing, became

unfeasible. The Papago Indians in Arizona

have requested a solution to the depletion of

reservation ground water supplies by municipal, agricultural, and mining sources, and the

Fort McDowell Indians of Arizona objected

vigorously to a Bureau of Reclamation plan to

build the Orme Dam that would force them to

abandon traditional lands. On the Umatilla reservation in Oregon, Indian fishermen lost their

fishing rights with the construction of the

Dalles Dam on the Columbia River, and have

sued to regain them.

Until recently, few incentives have existed

for the quantification of Indian water rights,

Throughout the history of water-project development, Congress and the executive branch

have seldom taken reserved rights into account

in development, Both the Colorado River Compact and the Upper Colorado River Compact,

for example, are silent on Indian claims to

water, The assumption was that such rights

would be satisfied within the quantities allocated to each basin and to each State.

Now, increased pressures on existing supplies has brought this issue into sharp focus,

in many cases through litigation (table 29). Pursuant to Federal law, States can negotiate for

the Federal Government on these matters.

Some States (e.g., Utah, Arizona, and Montana)

are negotiating with Indian tribes to seek settlement of claims. However, the evidence is not

yet available as to whether these experiments

will provide equity and fairness to all parties

and will avoid future litigation.

Efforts to settle conflicts involving Indian

claims have failed, both legislatively and administratively, at the national level. Ironically, Federal mechanisms for participation and
Ch. V—/r)stitutions Affecting Western Agricultural Water Use ● 121

Table 29.—Status of Settlement of Western Indian Claims

This table summarizes the decisional and settlement processes used in the river basins, or sections of basins, where

there have been significant clashes between Indian and non-lndian claims to water. A few cases have not matured to the point

where the parties have initiated any formal process, and these are omitted from the table.

Litigation

Arizona:

Main stem of Colorado River below Hoover Dam. . . . . . . . . .

Lower Colorado River between Grand Canyon

and Lake Mead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

Kanab Creek within Lower Colorado River Basin . . . . . . . —

Little Colorado River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gila River Watershed, except Santa Cruz Basin . . . . . . . . ●

Salt River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

Santa Cruz Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Groundwater Basin in Gila River Basin

(Ak-Chin) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –

Transbasin diversion from Colorado River

to Gila Watershed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

California:

San Luis Rey River. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s

White River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

Klamath River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Colorado:

Animas, Mancos, Los Pines, La Plata and

other tributaries of San Juan River . . . . . . . . . . . . . . . . . . . . . ●

Idaho:

Rapid River in Salmon River System . . . . . . . . . . . . . . . . . s

Kootenai River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

Montana:

Tongue River, Yellowstone Basin . . . . . . . . . . . . . . . . . . . . c

Big Horn River, Yellowstone Basin . . . . . . . . . . . . . . . . . . . ●

Milk and St. Mary Systems. . . . . . . . . . . . . . . . . . . . . . . . . . ●

Big Muddy, Poplar, Milk and Missouri

Rivers (Fort Peck) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s

Flathead River System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Flathead Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Marias River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s

Nevada:

Groundwater Basin in Walker River Basin... . . . . . . . . . . ●

Owyhee River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

Duckwater Valley and Muddy Creek Basins . . . . . . . . . . . —

South Fork of Humbolt River . . . . . . . . . . . . . . . . . . . . . . . . —

Truckee and Carson Rivers . . . . . . . . . . . . . . . . . . . . . . . . . . G

Clear Creek, tributary of Carson River . . . . . . . . . . . . . . . . —

New Mexico:

San Juan River, within Upper Colorado

River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c

Nambe—Pojoaque—Tesuque River System,

tributary of Rio Grande . . . . . . . . . . . . . . . . . . . . . . . . . . . Q

Santa Cruz River system and Rio de Truchas,

tributaries of Rio Grande . . . . . . . . . . . . . . . . . . . . . . . . . c

Rio Grande del Rancho, Rio Pueblo de Taos, Rio

Chiuito and Other tributaries of Rio Grande . . . . . . . . . .

Chama River and tributaries between El Vado

Dam and confluence with Rio Grande . . . . . . . . . . . . . . ●

Bonito, Hondo and Ruidoso Rivers,

tributaries of Pecos River . . . . . . . . . . . . . . . . . . . . . . . . . s

Santa Clara River, tributary of Rio Grande. . . . . . . . . . . . . Q

Chaco River, part of San Juan River drainage . . . . . . . . . . .

Rio Puerco (west), tributary of Little Colorado

River in Lower Colorado Basin . . . . . . . . . . . . . . . . . . . . ●

Rio Grande . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

Rio San Jose, within Rio Grande Basin . . . . . . . . . . . . . . . —

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122 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 29.—Status of Settlement of Western Indian Claims—Continued

Litigation

Oregon:

Williamson River in Klamath River Basin. . . . . . . . . . . . . . ●

Umatilla River, tributary of main stem

of Columbia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

South Dakota:

Missouri River and tributaries in

western South Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Lake Andes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Utah:

Duchesne River and Tributaries, Green

and White Rivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . —

Washington:

Yakima River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

No Name Creek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Chamokane Creek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Groundwater Basin (Lummi) . . . . . . . . . . . . . . . . . . . . . . . . . ●

Skagit River, and tributary, Copper Creek . . . . . . . . . . . . . ●

White River, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Western Washington rivers containing traditional

fishing grounds of tribes signatory to any of

five treaties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Payallup River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

Quinault, Queets and Raft River Systems . . . . . . . . . . . . .

Skokomish River System . . . . . . . . . . . . . . . . . . . . . . . . . . . ~

Dungeness, Skagit, Snohomish, Stillaguamish,

Pilchuk, Snoqualmie basins, and off-shore sites

in Strait of Juan de Fuca and Puget Sound . . . . . . . . . ●

Wyoming:

Big Horn River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ●

SOURCE: John A. Folk-Williams, ”What lndian Water means to the West:’ Water in the West,

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negotiation with Indian interests have been

severely reduced in recent years. Unless the

Federal Government establishes a full commitment to resolve the issues surrounding Federal

reserved rights and a focal point for negotiation, uncertainty and confusion for Western development, including Western agriculture, will

continue.

Water-Quality Regulation

As noted above, in the 1800’s the Federal

Government chose to defer to the States on

matters of control and development of local

water supplies. In the mid-1900’s, however,

there was a gradual shift back toward more

Federal regulatory interest in water. This occurred in the area of water quality, an aspect

of Western agricultural water use that affects

both the quality of water needed in agriculture

and the quality returned to the natural system

after agricultural use (see ch. IV).

Federal involvement in water quality control

has moved State agencies forward in waterquality regulation. A significant example of

Federal action that has had major impact on

State programs was the passage of the Federal

Water Pollution Control Act of 1972, amended

by the Clean Water Act of 1977 (together commonly referred to as the Clean Water Act, Public Law 92-500). Through the combination of

two mechanisms, a permit system for point

sources of pollution and instream standards of

water quality, the U.S. Environmental Protection Agency and the States are obliged to impose restrictions on effluents entering a stream,

They are also to undertake steps necessary to

ensure that water-quality standards are met.

Nonpoint source pollution, especially from

agriculture in the form of salts and agricultural
Ch. V—Institutions Affecting Western Agricultural Water Use . 123

— —

chemicals, received more attention with the

passage of the Clean Water Act. Section 208

of that act authorized and directed the Secretary of Agriculture to establish programs to implement “best management practices” on

farms and ranches to control nonpoint source

pollution from agriculture. Technical assistance and financial support were initially provided. Now, with Federal assistance effectively

eliminated, most States rely on voluntary action and cooperation to achieve nonpoint pollution reduction.

Interstate and International

Agreements

Interstate and international agreements dealing with Western river systems are important

attempts to recognize politically the regional

nature of surface water regimes and the need

to manage them as total units. Existing agreements define some framework for water use

by different parties of interest. At the same

time, uncertainty has been created by the potential constraints of some of the provisions as

water quality and quantity limits are reached

and strict enforcement measures become necessary to ensure compliance. These interstate

and international agreements affect all Western

water users. As compliance becomes a matter

of increased concern, these agreements will influence decisions about the kinds of waterrelated technology acceptable for meeting compact water quality and quantity obligations effectively. The major Western agreements are

noted below.

Interstate Compacts

The major provisions of the Colorado River

Compact of 1922 are (28):

I. It divides the river system into the Upper

and Lower Basins and allocates 7.5 million

acre-feet per year (maf/yr) to each basin for

beneficial consumptive use. The Lower Basin is also given authority to increase its annual use by 1 million acre-feet (maf).

2. It does not recognize a specific obligation

to provide water to Mexico. However, a

framework is established whereby any future obligation would be shared equally between the Upper and Lower Basins.

3. The Upper Basin is prohibited from reducing the flow at Lee Ferry to below an aggregate of 75 maf in any 10-year period. The

Upper Basin is not to withhold water, nor

is the Lower Basin to demand water that

cannot reasonably be applied to domestic

and agricultural uses,

The Boulder Canyon Project Act of 1928 provided for the construction of Hoover Dam and

its powerplant and for the All-American Canal.

Its major provisions were:

1,

2.

3.

It suggests a specific framework for apportioning the water supplies allocated by the

compact of 1922 among the Lower Basin

States of California, Arizona, and Nevada,

(The States did not adopt this framework,

but it was later imposed on them by the Supreme Court decision in Arizona v. California, 376 U.S. 340 [1964].)

It requires California to reduce its annual

consumption to 4.4 maf plus not more than

half of the surplus water provided to the

Lower Basin. (This requirement was met

through the California Limitation Act of

1929.)

It authorizes the Secretary of the Interior to

investigate the feasibility of projects for irrigation, power generation, and other purposes.

In the Upper Colorado River Basin Compact

of 1948 the Upper Basin States apportioned the

water allocated under the compact of 1922, The

negotiators recognized the problem inherent

in allocating water on a strict-quantity basis because of flow fluctuations from year to year,

As a result, water was apportioned on a percentage basis to all States except Arizona, Major provisions of the compact are (28):

1.

2,

Arizona is guaranteed 50,000 acre-ft/yr,

The remaining water is apportioned as

follows:

Q Colorado: 51.75 percent

c New Mexico: 11.25 percent

c Utah: 23.00 percent

● Wyoming: 14.00 percent.

It recognizes that new reservoirs will be

needed to assist the Upper Basin in meeting

its delivery obligation to the Lower Basin.

The compact provides that charges for
124 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

such evaporative losses be distributed

among the Upper Basin States. Each State

is to be charged in proportion to the fraction of the Upper Basin’s water allocation

consumed in that State on a yearly basis,

and its maximum consumptive use is to be

reduced accordingly.

3. It provides for the division of water between pairs of States on a number of specific rivers.

Being in a position to use water available

under these compacts has been a problem for

some States. For example, the 1922 Colorado

River Compact legally guaranteed the State of

California 4.4 maf of Colorado River water annually. Yet California has used approximately

5.7 maf every year because it has had the physical structures to convey and use the extra

water, while other States have not had this

capacity. The Central Arizona Project (CAP),

a massive water system which will lift the

water almost 2,000 ft in elevation and carry it

over 300 miles to make use of Arizona’s share,

should make its first delivery in 1985 to Phoenix, shifting water away from California users

to Arizona users. *

International Agreements

In the Mexican Water Treaty of 1944-45 the

United States promised the Republic of Mexico that 1.5 maf of water will be delivered to

Mexico every year through the Colorado River.

This provision was part of the negotiations

over apportionment of water from the Rio

Grande, Tijuana, and Colorado Rivers. The

States in the Upper and Lower Colorado Basins

were apportioned 7.5 maf for each group of

States.

The treaty with Mexico had not been made

when the Colorado River Compact was signed.

But article III(c) of the compact provides that

if the United States recognizes any Mexican

rights in the river, these rights would be filled

“first from the waters which are surplus over

and above the aggregate amount” allotted to

the Upper and Lower Basin States (1.5 maf plus

*For a discussion of the major social, economic, and political

issues surrounding the CAP, as well as a physical description

of the project, see ref (14).

whatever the Lower Basin States have been

able to use, up to 1 maf/yr).

If the surplus is not adequate to fill the obligation to Mexico, the “burden of such deficiency shall be equally borne by the Upper and

Lower Basin . . . .“ In short, if the “surplus”

waters of the Colorado River are less than 1.5

maf annually, existing rights in the United

States could be cut short to make up the difference owed to Mexico. Moreover, under international agreement with Mexico, the quality of the 1.5 maf was to be improved through

the Water Salinity Control Project at Yuma,

Ariz. (see ch. VII for discussion of desalting

techniques).

The Columbia Treaty of 1964 concluded two

decades of study and negotiation by the United

States and Canada for joint development of the

Columbia River basin. For the United States,

large quantities of Canadian storage were acquired to meet certain flood-control objectives

in the Northwest States and to provide power

through the Bonneville Power transmission

system to the Pacific Northwest, California,

and to the Southwest. When enacted, its focus

was not principally on irrigation, a domestic

matter within the concept of multiple-purpose

development of U.S. rivers. Eventually, the

treaty may restrict the entry of new agricultural users, since such users would have junior

rights to existing power rights and hydroelectric power requirements may not be compatible with timing needs of new users. In this

sense, hydroelectric power will become a competing use for new irrigation farmers.

Implications for Sustainable

Western Agriculture

State and Federal water-law doctrines have

helped define general rights and duties. As

demands for the limited resource have grown,

however, uncertainties have increased about

the specific meaning of these rights regarding

more intensive water use, potential new users,

and opportunities for water transfers and reallocation. A substantial part of the uncertainty

concerns the nature of the water right held by

an individual. For example, in California,
Ch. V—Institutions Affecting Western Agricultural Water Use . 125

which has attempted to quantify water rights,

appropriative rights acquired before 191+1 are

not required to be recorded, Post-1914 rights

were, until 1969, recorded regarding flow rate

and seasonal restrictions but omitted total

quantities. Even where water rights have been

recorded, the quantities of water claimed may

be exaggerated, thus largely destroying the

utility of the record (12). In addition, uncertainties about the quantities of water involved with

Indian and other Federal reserved water rights

cloud the titles of many recorded private appropriative rights, and Federal commitment to

negotiate and resolve these issues is lacking.

Problems have also grown regarding the artificial separation of water into legal classes.

Surface and ground water rights are administered along different well-established doctrines,

as discussed above. Nevertheless, these surface-subsurface waters are connected physically and interact both quantitatively and qualitatively. Rights in atmospheric moisture, a relatively new legal area, are poorly defined because interception technologies are relatively

new, although a few States have begun to claim

sovereign rights to atmospheric moisture (see

ch. VI). If precipitation makes its way to the

ground as diffused surface water, the runoff

may become subject to other types of water

rights before it reaches the streamcourse or

ground water. In some States, use of diffused

surface water (not yet concentrated in a channel) impounded for certain purposes by a landowner must be secured through special procedures. No State has gone so far as to actually

appropriate diffused surface water (26). *

● For a thorough discussion of the impacts of Federal agricultural production programs on soil and water resource management in general see the OTA assessment: Impacts of Technology on U.S. Cropland and Rangeland Productivity, ch. VI, OTAF-166, August 1982.

SOCIOECONOMIC FACTORS AFFECTING

WESTERN WATER INSTITUTIONS

The social and demographic trends that characterize the West have been shaped by economic opportunities and institutional forces.

Such opportunities have been and continue to

be conditioned by the distribution and availability of water resources.

Demographics

In many ways, unmanaged population growth

constitutes a major long-run threat to agricultural growth and development in the West. People increase demands not only on water supplies but also on space. Since cities grow more

easily on level terrain, farmers and urban developers compete for the same valleys. Population increases promote commercial and industrial sectors of the economy, which in turn

attract more people in search of jobs. Much of

the West is fully involved in this spiral, and

local conflicts over land and water use are

becoming commonplace.

Regional population-growth patterns have

shifted in the past three decades. Figure 29

compares the rate of growth for the 17 Western

Figure 29.-Popuiation Rate of Change of the

17 Western States Compared to the U.S. Population,

Rate of Change, 1930-80

1930 1940 1950 1960 1970 1980

Year

SOURCE: Office of Technology Assessment staff, from U S. Department of

Commerce, Bureau of the Census, 1980 Census of Population and

Housing, advance reports

States with that of the entire United States. All

four U.S. census regions gained population in

each of the intervals between the last three censuses (fig, 30). The Western census region (note

that this region does not include all 17 Western

States) grew fastest, although its population in-
126 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Photo credits: USDA-Soil Conservation Service

Suburban growth of Santa Clara County, Calif., during 28-year period (April 1950 to April 1978). Photo (top shows the

area that was predominantly agriculture now covered with highways, housing developments, and industry (bottom)
Ch. V—Institutions Affecting Western Agricultural Water Use ● 127

Figure 30.—United States: Census Regions and Divisions

SOURCE u s Department of Commerce Bureau of the Census. Statlstlcal Abstract Of the United States 1981 (102d ed ) (Washingfon D C 1981)

Components of Population Growth in Regions and Divisions: 1950-80 (numbers In millions)

——

Population Population Net Population Net Population

Regions and divisions 1950 1960 migration 1970 migration 1980

Northeast . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . ... , . . . 39.5 44.7 + .3 49,0 + .3 49.1

New England . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 10.5 + .0 11.8 + .3 12.3

Middle Atlantic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.2 34.1 + .3 37.2 + .0 36.8

Northcentral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.5 51.6 - .1 56.6 - .8 58.9

East Northcentral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.4 36.2 + .7 40.3 - .2 41.7

West Northcentral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.1 15.4 - .8 16.3 - .6 17.2

South . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47.2 55.0 -1.4 62.8 + .6 75.3

South Atlantic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.1 26.0 + .6 30,7 + 1,3 38.9

East Southcentral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5 12.0 -1.5 12.8 - .7 14.7

West Southcentral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.5 17.0 - .6 19.3 - .0 23.7

West. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.6 28.1 + 3.8 34.8 + 2.9 43,2

Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 6.9 + .6 8.3 + .3 11.4

Pacific . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.5 21.2 + 3.3 26.5 + 2.5 31.8

SOURCES’ Bureau of the Census, 1950-70, Revised Estimated of the Population of States and Components of Change, Current Population Reports Series P.25, Nos.

— —

3-4 (1985) and 460 (1971). Bureau of the Census, 1970-80, 1980 Census United States Summmary Final Population and Housing Unit Counts (Advance Reports)

PHC 80 V-1, 1981, table 1.
128 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

crease dropped from 39 percent in the 1950’s

to 24 percent in the 1970’s. The Pacific division within this region grew faster in the 1950’s

and 1960’s, while the Mountain States attracted

more population growth in the 1970’s (23).

State-by-State percentage change in population

for the 17 Western States is indicated in table

300

By 1980, the population of the South and

West exceeded that of the two northern regions

for the first time. California was the most populous State, with 23.7 million people—far ahead

of second-place New York, with 17.6 million

(23),

For the period 1970-80, population growth

in the West was above the national average

with the exception of the Dakotas, Kansas, and

Nebraska (table 30). For California, Texas,

Arizona, and New Mexico, the increases were

dramatic. Since the natural increase in population (births minus deaths) is relatively constant

throughout the country, the large total increases in the West have been due to positive

net migration: from 1970 to 1976, 623,000 for

California; 543,000 for Texas; 356,000 for Arizona; 237,000 for New Mexico; and 1,849,000

for the entire West.

Both push-and-pull factors explain the population flux to the West. Climate certainly carries significant influence. perhaps equally important is the reluctance of many to endure the

inconveniences of city life and the popular perception that Western cities and towns offer a

rural-like setting and relaxed lifestyle without

a loss of necessary services. Industry seeks

what is referred to as “unexportable amenities.” A warm, dry climate extends the use-life

of capital goods and reduces shutdowns from

adverse weather. Also, a growing population

of employable persons ensures both a labor

force and a demand for manufactured items.

Commercial interests respond to urban population changes by developing the service sector.

As a consequence, from 1970 to 1977, the West

experienced an increase in nonagricultural

employment three to four times higher than the

national average (table 31). And whereas manufacturing employment in the United States actually declined over the same period, most

Western States registered a dramatic increase,

The broadening of job opportunities that accompanies the growth of industry and business

promotes a regional image of abundant employment, thus drawing larger migrant flows.

Population trends for the 1980’s indicate that

the population shift to the South and West will

continue but will not accelerate as it did in the

1970’s. The question is more open, however,

regarding the movement to nonurban areas.

Table 30.— Percentage Increases in Population for the 17 Western States and United States, 1930-80

State 1930-40 1940-50 1950-60 1960-70 1970-80

Arizona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.6 50.1 73.7 36.3 53.1

California. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.7 53.3 48.5 27.1 18.5

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 18.0 32.4 26.0 30.7

Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.9 12.1 13.3 6.9 32.4

Kansas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -4.3 5.8 14.3 3.2 5.1

Montana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. I 5.6 14.2 2.8 13.3

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -4.5 0.7 6.5 5.2 5.7

Nevada. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.1 45,2 78.2 71.6 63.5

New Mexico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.6 28.1 39.6 6.9 27.8

North Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -5.7 -3.5 2.1 -2.2 5.6

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -2.5 -4.4 4.3 9.9 18.2

Oregon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.2 39.6 16.3 18.3 25.9

South Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -7.2 1.5 4.3 -2.2 3.6

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 20.2 24.2 16,9 27.1

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 25.2 29.3 18.9 37.9

Washington. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 37.0 19.9 19.6 21.0

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 15.9 13.6 0.6 41.6

17 States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 25.8 29.4 19.4 22.4

Total United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 14.5 18.5 13.4 11.4

SOURCE U.S. Department of Commerce, Bureau of the Census, 1980 Census of Populatlon and Housing, advance reports, from Statistical Abstract ’81, p, 10.
—

Ch. V—Institutions Affecting Western Agricultural Water Use 129

Table 31.- Population and Employment Change by Region and State

Percent change in Net migration Percent change in employment

Population population 1970-76 1970-77

Regions 1976 1970-76 Number Percent Nonagricultural Manufacturing

. — — California . . . . . . . . . . . . . . . . . . . . ... , 3.1 20.6 7.1

Intermountain:

Idaho. . . . . . . . . . . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . . . . . . . . . .

Southwest:

Arizona . . . . . . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . . . . . . . .

Northern Plains:

North Dakota. . . . . . . . . . . . . . . . . . .

South Dakota . . . . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . . . . . . . .

Southern Plains:

Kansas . . . . . . . . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . . . . . . . . .

21,510,000 7.8 623,000

831,000

753,000

2,329,000

3,612,000

16.5

8.4

11.3

5.8

64,000

25,000

159,000

64,000

8.9

3.7

7.6

1.9

44.2

21.3

25.2

17.1

29.5

-2.5

10.8

3.9

2,270,000

2,583,000

610,000

1,168,000

1,228,000

27.9

16.9

24.8

14.9

15.9

356,000

237,000

91,000

67,000

35,000

20.1

10.7

18.5

6.6

3.3

43.7

32.3

44.5

37.6

32.7

20.3

18.6

62.0

46.6

32.7

643,000

686,000

390,000

-4,000

-9,000

37,000

-0.6

-1.3

11.3

34.1

21.1

45.9

4.9

31.0

9.5

4.1

3.0

17.4

2,310,000 2.7 -13,000

-0.6

0.8

4.2

4.9

25.7

18.5

25.3

32.3

24.2

5.3

19.9

17.6

1,553,000

2,766,000

12,487,000

4.5

8.1

11.5

11,000

107,000

543,000

Total United States . . . . . . . . . . . . . . . 214,659,000 5.6 2,857,000 1.4 8.6 -1.3

SOURCE Flnan, et al, 1982. Original source: Bernard L. Weinstein and Robert E. Flrestlne, Regional Growth and decline in the United States (New York: Praeger Publishers,

1978)

.

Photo credit Jack Schneider, ISP

Skyline of Denver, Colo., 1974—a Western metropolis at the hub of growth and urban development
130 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

During the first half of the 1970’s, one of the

major demographic surprises was a reversal of

the rural-to-urban population flow, the first

time this had occurred since the beginning of

the century. This outmigration appears to be

to counties adjacent to major metropolitan

areas, however, and not to rural counties more

removed from urban areas.

A panel of experts assembled by the Population Reference Bureau has projected continued

rapid migration to the Mountain States (Arizona, Colorado, Idaho, Montana, Nevada, New

Mexico, Utah, Wyoming) in the 1980’s. While

some of this population movement will be related to mining activities, most will be related

to resort-retirement growth and suburbanization. According to these experts, “diminishing

water supplies will eventually restrain population growth in the West, but not yet in the

1980’s” (23). In the meantime, recent population increases in the West are related, for the

most part, to nonagricultural activities. Regional water-use priorities that traditionally favored

agriculture may be affected by this trend to a

more urban/suburban voting population.

Rural Economics and

Western Agriculture

In much of the West, as in the rest of the

United States, the farm population is comparatively low. Western farm population has

dropped to about 3 percent of the total population, close to the 1981 national average (table

32). The ratio of agricultural income to nonagricultural income averages somewhat less than

3 percent in the southern half of the West and

7.5 percent in the Plains area (30). Agriculture

itself directly supports a small population;

however, as a regional activity it has become

an integral part of local economies. Agriculture

contributes to such local and regional activities

as grain-elevator operation, transportation, and

food processing. In Texas, for example, every

dollar of farm sales leads to more than $3.40

in the Texas economy (5).

A large, complex economy such as that of the

United States is made up of thousands of subeconomies. In the 50 United States, there are

over 3,000 counties and approximately 20,000

municipalities, most with populations of less

than 2,500 people (3). These small towns are

primarily agricultural service centers and are

highly dependent on the agriculture that surrounds them.

The irrigation of agricultural areas in the

West has changed the productivity of their

resources and hence their economic bases. Irrigating large parts of Arizona has changed that

Table 32.—Total and Farm Population of the United States: 1920-81 (numbers in thousands)

Farm population

Year Total resident population Number of personsb Percent of total population

Current farm definition1981 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224,064 5,790 2.6

1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221,672 6,051 2.7

1979 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219,611 6,241 2.8

1978 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217,771 6,501 3.0

Previous farm definition:

1981 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224,064 6,942 3.1

1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221,672 7,241 3.3

1979 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219,611 7,553 3.4

1978 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217,771 8,005 3.7

1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215,966 7,806 3.6

1976 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214,282 8,253 3.9

1975 . . . . . . . . . . . . . . . . ... , . . . . . . . . . . . . . . . 212,542 8,864 4.2

1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203,235 9,712 4.8

1960 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179,323 15,635 8.7

1950 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150,697 23,048 15.3

1940 . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . 131,669 30,547 23.2

1930 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122,775 30,529 24.9

1920 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105,711 31,974 30.2

aOfficial census counts, except 1975-81, which are estimates.

bFarm population estimates for 1920 to 1970 from Farm Population Estimates, 1910-70, U.S Department of Agriculture, Statistical Bulletin No. 523 JUIY 1973; fivequarter averages centered on April beginning 1980. See app A.

SOURCE U S Department of Commerce, Bureau of Census, “Farm Population of the United States” 1981, ” November 1982, p 1
Ch.--Institutions Affecting Western Agricultural Water Use ● 131

area from one that produced cattle to an area

that produces citrus crops, cotton, and other

high-valued commodities. The irrigation of

some parts of southern California has permitted that area to switch from essentially no

agricultural production to an area that produces many of the Nation’s winter vegetables.

Irrigating Washington State’s Columbia basin

has changed that region from extensive cattle

These changes, however, are not made in a

vacuum. Once the major change occurs in agriculture, the effects spread to nonfarm parts of

the society and the economy. Reactions to

change in an economic base are site-specific,

A cattle-producing area that suddenly has

water to irrigate some of its hay-producing land

may not change at all. A desert that is made

to produce many labor-intensive crops will

grazing to the highly

hay, sweet corn, and

intensive cultivation of change demonstrably. In the latter case, nearpotatoes. by towns–as well as the farms–grow, develop,

Box G.—Economic Impacts of Irrigation on the West

The Grand Valley trade area in western Colorado has been irrigated by Bureau of Reclamation

projects for many years. A 1963 study of the area showed that water was used on 3,999 farms (95.9

percent of all farms) and that nearly all of the cropland as well as some of the hay-producing land

was irrigated (Struthers, 1963, in Barkley, 1983). In 1960 the 273,000 irrigated acres helped produce agricultural commodities valued at $27.6 million-38 percent of the area’s total product.

Agriculture was also estimated to be responsible for 18 percent of the “linked” or secondary employment in this area. This amounted to 1,026 persons who produced processing services valued at

over $18 million. The analysts responsible for the study also estimated that agriculture was responsible for 7,500 to 10,000 jobs in the general sectors of the local economy. The entire influence of

irrigated agriculture is summarized in ratios showing that for each dollar of income originating

in agriculture, an additional $1.97 to $2.68 is generated in the local nonfarm sector.

The Columbia Basin Irrigation Project in central Washington was planned almost since the

Bureau of Reclamation was formed in 1902 (Corssmit and Barkley, 1975, in Barkley, 1983). The

irrigation components of the project became a reality in 1950, and by 1970 over 500,000 acres were

irrigated using water supplied by the public project. The land that came under irrigation had

previously been of little agricultural value and had been used almost exclusively for grazing cattle

and sheep. After two decades of development, the area was reaching economic maturity, which

involved massive expenditures by Federal, State, and local governments. By 1970 the Federal

Government had invested $6.6 million in nonproject costs in the area (in addition to the direct

costs of water delivery), the State and county governments had invested $258 million, and the many

local governments had invested $25 million. In addition, utility companies serving the expanding

populations invested $198 million. This represents a total investment of $8,032 per capita that was

required to install an “appropriate” amount of social overhead capital in the area.

The High Plains area of eastern Colorado began to switch from dryland farming to irrigated

farming in the 1960’s. The development was carried out by individual farm operators who sunk

wells into the Ogallala aquifer. Development was quite rapid. In 1966, 366 wells were registered

with the State Ground Water Commission. By 1970, at least 2,000 wells were registered and in

use (Rohdy, et al., 1971 in Barkley, 1983). The development occurred in a sparsely populated region

and centered on towns that were quite small. The effects of irrigation farming are quite extensive

and can be shown as “business multipliers, “ indicating the increase in nonfarm business that accompanies each dollar of economic activity in irrigated agriculture. The results of a 1973 study

show that there was 77 cents of nonfarm business generated for each dollar of economic activity

on irrigated farms.

SOURCES : P. Barkley, “The Sustainability of Rural Non-Farm Economics in Water Dependent Agrricultural Areas,’ OTA commissioned paper, 1983.

C. W. Corssmit and P. W. Barkley, “Water Resource Development Related Social Overhead Capital Expenditures in the Columbia Basin 1950-1970,”

paper presented at the annual meeting of the American Agricultural Economics Association, Columbia, Ohio, 1975. In: Barkley, 1983.

D. D. Rohdy, D. B. Tanner, and P. W. Barkley, “Secondary Economic Effects of Irrigation on the Colorado High Plains,” Colorado State University

Experiment Station Bulletin 5455, June 1971. In: Barkley, 1983.

Robert E. Struthers, “The Role of Irrigation Development in Community Economic Structures,” U.S. Department of the Interior, Bureau of Reclamation, February 1963.
132 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

and change. Lifestyles and business patterns

are affected. The growth requires the commitment of personal, social, and capital resources that, once put in place, are very hard

to move (3).

Because of such investments, the possibility that irrigation may end in some areas of the

West is generating increased attention. Irrigated agriculture could be diminished for a

number of reasons. The availability of affordable water supplies could change (see ch. X),

as in parts of Texas over the Ogallala aquifer,

or competition could cause water to be shifted

from agricultural to other users who can pay

more, as in parts of Arizona and Colorado.

Similarly, irrigation could damage the soil with

salt buildup over time (see ch. VIII) to the

degree that some areas cannot be economically farmed, as in parts of New Mexico and California.

Where competition diminishes agricultural

use of water (e.g., when large energy companies buy major water rights), the economy

of the area may remain strong even though particular patterns of community life and business

may be changed as shifts take place away from

an agricultural to an industrial/mining economy. Such change may have serious and in

some cases negative social effects (even with

the emergence of a stronger economy) on

others in the local community who may not

have chosen to elect that change. Other areas

may be able to remain in irrigated agriculture

only with large subsidies in water or energy.

Thus, social costs are also incurred, this time

by the taxpayer.

These varying consequences underscore the

importance of taking into account short- and

long-term effects on local farm and nonfarm

economies of public investments made in Western water use and agriculture. The question increasingly asked is whether new investments

can generate a sustainable Western agriculture

that is relatively stable for social and economic growth over the long term or whether the

investments will be more productive in another

sector of the economy.

Competition for Western Water

Water supplies can be used to support farming, mining, industry, urbanization, or combinations of these activities. The socioeconomic

character of a region is influenced substantially

by which of these activities enjoys the greatest

relative control over water resources. Traditionally, agriculture has been dominant in establishing and maintaining the particular flavor

of Western living and, to a large extent, has

defined the economic, political, and cultural

legacy of the region (11). In the past, federally

subsidized water has placed irrigated agriculture in a favorable competitive position with

other uses of water. Changes in Federal funding policies may affect the competitive advantage of irrigated agriculture and have ramifications for future agricultural production and the

kinds of water-related technologies attractive

to the producer. As Western populations expand in nonfarm sectors, greater demand is

placed on land and water resources formerly

used by farmers and ranchers (table 33). Decisions about who will get water may increasingly be affected by the “value” or “cost” of

the water and by which competing users will

be willing and able to pay. Major competitors

for Western water are noted below.

Western Indians

As discussed in detail earlier in this chapter,

some Indian claims are being defended in agricultural and nonagricultural uses, including instream uses such as fishing. The American

Indian is a potentially large group of competitors. While quantification of many of their

claims is unsettled, the potential impact of the

amounts involved on all other existing rights

created after the establishment of their reservations is substantial.

Energy and Mining Uses

One of the largest industrial developments

affecting recent water policy in the arid/semiarid region is the growth of the energy industry

(z). Although the west coast and other urban

centers have developed a diversified manufac-
Ch. V—Institutions Affecting Western Agricultural Water Use ● 133

Table 33.—Projections of Changes in Total Cropland and Irrigated Farmland by State, 1975-2000

Change in percent of cropland Acres of irrigation farmland (1000 acres)

Regions 1975-1985 1985-2000 1975 1985 2000

California . . . . . . . . . . . . . . . . . . . . . . . . . . - 20/0 - 5% 8,495 9,132 9,854

Intermountain:

Idaho . . . . . . . . . . . . . . . . . . . . ... , . . . . +1 ”/0 - 1 % 2,989 3,351 3,400

Montana . . . . . . . . . . . . . . . . . . . . . . . . . +1 ”/0 +1% 2,010 2,967 2,904

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . - 1 % - 1 % 1,742 1,987 2,096

Washington ., . . . . . . . . . . . . . . . . . . . . +1 ”/0 - 1 % 1,421 1,809 2,013

Southwest:

Arizona . . . . . . . . . . . . . . . . . . . . . . . . . . - 30/0 - 60/0 1,207 1,112 1,057

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . +1 ”/0 +1% 3,313 3,156 3,375

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . 39% 38% 828 737 773

New Mexico . . . . . . . . . . . . . . . . . . . . . . - 1 % - 1 % 956 877 816

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1% +1% 1,056 979 1,062

Northern Plains:

North Dakota. . . . . . . . . . . . . . . . . . . . . + 1 % + 1 % 94 126 230

South Dakota . . . . . . . . . . . . . . . . . . . . . - 1 % - 2 % 218 274 380

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . 2% 1% 1,731 1,818 1,874

Southern Plains:

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . 7% 8% 2,044 2,618 2,823

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . +1% +1% 4,315 4,858 5,118

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . +1% 1% 566 580 589

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . +1% - 1 % 7,414 6,886 6,170

SOURCE: Finan,et al, 1982 Original source US. Water Resources Council, TbeNation's Water Resourcces, 1975-2000, vol 2,pt llI, tableilP29, 1978

turing sector, energy development has been the

principal industrial force in such areas as the

northern Great Plains and Rocky Mountain

States, and both boom towns and company

towns dot Western maps. The relatively recent

surge of the energy industry, particularly coal

and oil-shale mining, has brought increased

economic opportunities to many Western

areas.

Most estimates of demand for water for energy production, slurry-line transportation, and

cooling purposes conclude that energy demand

for water on a regional scale is relatively small

compared with that of irrigated agriculture.

However, on a site-specific basis, increased

water use to meet energy demand in such areas

as the Rocky Mountain States will have a significant impact on the availability of water for

other purposes, especially for agriculture (18).

Ultimately, the quantities of water ’’required”

for energy production at a particular site will

be affected by the cost the producing industry

must pay for that water and associated restrictions put on its use (see ch. III). Much of the

future of energy production in the West hinges

on the ability of energy-producing firms to bid

water away from irrigated agriculture (16) (see

discussion in app, C on the value of water in

alternative uses).

The competition for water between farms

and mines also raises arguments over the desirability of development paths and the kinds

of practices used by each. AS extractive operations, mines are limited by the quantity, quality, and world price for mineral products, and

the rise and fall of boom towns underscore the

cyclical nature of this activity. Mining operations use land and water as short-run inputs

and with full awareness of their eventual degPhoto credit: © Ted Spiegel, 1982

Mining Wyoming soft coal. Proposals to transport in

slurry pipelines to Eastern markets would require

extensive off stream water resources
134 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

radation or depletion. Farms and ranches may

be perceived to use land and water on a more

permanent and beneficial basis; however, some

present Western agricultural practices are

degrading land and water both (see e.g., chs.

VI, VIII, and X).

Municipal and Other Industrial Uses

Municipalities and nonmining industries use

a relatively small fraction of the total amount

of water used in the West. In table 34 this fraction is compared with agricultural use for some

States of the West. Municipal and industrial

water users are in a relatively favorable position with respect to future water supplies, owing to their superior financial capacity. In

many areas, municipalities have developed reliable supplies of water and have supplemented

these supplies by water from public projects.

As compared with some agricultural users,

they are accustomed to paying at a level closer

to full cost of development, transportation, and

purification. Federal law—and State law in

States such as California–requires municipal

and industrial users to pay their fully allotted

costs. Costs may rise substantially, but urban

and industrial water users will probably make

minor financial or lifestyle adjustments to accommodate these changes.

Municipal and industrial users are increasingly interested in future water policy, particularly with respect to new water-development projects. Some communities still see

growth as both a likely and desirable trend and

foresee the need for additional water to permit such growth to occur. Municipal and industrial leaders fear drastic shortages such as

those in the severe drought of 1977-78. The efforts of southern Californians to promote the

Peripheral Canal and its accompanying works

are evidence of this concern for seeking a

margin of safety in drought situations.

Moreover, surface water diversions used to

develop additional irrigated acres may increasingly compete with opportunities to develop

hydropower for municipalities and industry.

Whittlesey, et al. (33), studied the economics

surrounding the irrigation/hydropower tradeoff the Pacific Northwest and concluded that,

using present low values for irrigation water,

most new irrigation developments in the Pacific Northwest represent a net loss for the economy of that region. Instead water use is heavily weighted in favor of hydropower generation

because of the tremendous power-producing

potential of the many dams on the Columbia

River.

Resource Protection Uses

Agriculture must face competition and constraints on water use from interests concerned

with environmental protection and resource

conservation. Such interests have been successful in limiting access to new sources of

water by placing some water sources in a protected status-e. g., in the wilderness and scenic

rivers classification. The requirements for minimum streamflow standards have placed a new

limitation on consumptive use (see ch. III).

In those areas where underground aquifers

are being “mined,” as in Arizona and the Central Valley of California, pressure exists to impose limitations on the levels and rates of withdrawals and thus reach a sustainable balance

Table 34.–Rate of Change in Water Use as Percentage of Total Water Use, Municipal and Industrial (M&I)

v. Irrigation (Irrig.) Purpose in Selected States

1955 1960 1965 1970 1975 1980

Arizona (M&I) . . . . . . . . . . . . . . . 30/0 4% 60/0 80/0 10% 10%

(Irrig.) . . . . . . . . . . . . . . . . . . . 960/0 94% 94% 930/0 90 ”/0 890/o

North Dakota (M&l). . . . . . . . . . 630/o 30 ”/0 39% 650/o 780/o 74 ”/0

(Irrig.) . . . . . . . . . . . . . . . . . . . 300/0 49% 45%0 290/o 180/0 21 %

California (M&l) . . . . . . . . . . . . . 250/o 41% 40% 300/0 300/0 300/0

(Irrig,) . . . . . . . . . . . . . . . . . . . 75%0 580/o 600/0 690/o 690/o 690/o

Texas (M&I) . . . . . . . . . . . . . . . . 390/0 380/o 41%0 600/0 57% 580/o

(Irrig.) . . . . . . . . . . . . . . . . . . . 590/0 59 ”/0 56% 37% 41% 40 ”/0

Nebraska (M&I) . . . . . . . . . . . . . 220/0 270/o 20 ”/0 200/0 14% 91 ‘/0

(Irrig.) . . . . . . . . . . . . . . . . . . . 77 ”/0 690/o 780/o 780/o 780/o 780/o

SOURCE U S. Government Survey, Estimated Use of Water in the United States, publications for 1955-80 (Washington, DC.: U.S. Government Printing Office, 1955-80).
Ch. V—Institutions Affecting Western Agricultural Water Use 135

Photo credit: USDA-Soil ConservatlonService

Idaho wilderness, an example of water resources in a natural

state. Here, beaver dams provide natural water control

between extraction and recharge. In Arizona,

this pressure—largely from urban and industrial interests—has already resulted in legislation that will impose a “duty of water” on agriculture—in effect, a limitation on the quantities

of water that may be used in growing various

kinds of crops. The director of the Arizona

Department of Water Resources has been given

extraordinary authority to define the limitations under which water may be used and

powerful tools of enforcement to achieve these

legislative ends (see app. C). Other Western

States (e.g., Colorado and New Mexico) have

specific statutory policies authorizing the mining of those ground water acquifers with little

or no natural recharge capacity

Resource protection issues have broad implications for the West. Traditional water use and

development relationships have been substantially altered in recent years by a broadening

of interests related to water resources and

changing institutional goals with respect to

Western water development. At the national

level, environmental values have gradually

gained a more prominent level among public

priorities. The relative primacy of Federal

development agencies such as the Bureau of

Reclamation has been challenged. Legislation

has been enacted to strengthen the role of other

agencies or to create new agencies, such as the

Environmental Protection Agency. These policy developments have altered the missions of

traditional agencies by placing them in the context of a broader decisionmaking structure. A

most notable example is the passage of the National Environmental Policy Act (Public Law

91-190), which requires Federal agencies to

prepare environmental impact statements prior

to undertaking new projects. Support at the

local level has grown for retaining water resources in a natural state. In addition, the traditional sentiment that “development” (inferring

“growth” in quantity) is a positive value is no

longer uniformly held. Indeed, major new water-project developments may increasingly encounter significant opposition and competition

from distinct elements of the general public.

THE ECONOMICS OF WESTERN WATER

The market system allows property to be

bought and sold, and thus transferred between

uses and users. It forms the basis of the economic system in the United States and as such

can be subsumed under the general heading of

economics and, with respect to water, the economics of Western water.

A market depends on the rights of ownership

and the legal conditions for exchange. The

owner of a good as simple as a pitchfork has

complete rights to that pitchfork and can sell

it to a neighbor. Rights of ownership transfer

with the sale. The pitchfork will be sold if its

present owner feels the value of the money obtained in exchange equals or exceeds the value

of the pitchfork. All well-functioning markets

operate in this fashion. Exclusive goods—goods

that have well-defined and perfected rights attached to them—are exchanged whenever dispositions about their relative values differ,

If rights in water were as straightforward and

secure as rights in pitchforks (or even rights
136 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

in land), a highly developed and organized

water market would emerge. Irrigators would

purchase water from industries if irrigated

crops were worth more to farmers than water

for cooling or dilution was worth to industrialists. Public utilities would purchase water

from householders if the value in power generation was higher than the value of water for

green lawns and kitchen gardens. Wheat farmers would purchase irrigation water from corn

farmers if the value of wheat exceeded the value of corn by an amount sufficient to make the

transaction worthwhile.

A Market for Water

Although there are some areas where the

market does allocate water among uses and/or

users, market exchanges of water are not the

rule. Attempts have been characterized as

“rudimentary” and unorganized (4). An important exception is found in the Colorado-Big

Thompson project area of northeastern Colorado, where a relatively sophisticated market

has evolved (see app. C).

Valid reasons exist for the lack of water

markets. Many derive from legal and institutional factors affecting water use and exchange

that have evolved in the West, as discussed

earlier in this chapter. The appropriations doctrine assumes a sequence through time. “Prior

rights” for a particular use may impede an individual’s ability or desire to sell. The doctrine

of beneficial use may establish a hierarchy of

uses inconsistent with water moving to its most

economical use. The riparian doctrine and the

doctrines of correlative rights tie water to other

resources or to a particular geographic territory

and impede its transfer to other uses and users.

Other factors that hinder the formation of an

orderly market for water include the physical

characteristics of water, its variety of uses,

water’s use as a public good, external or thirdparty dependence on water, and the recent

emergence of water as a scarce, and hence

“economic, ” factor of production (34). The difficulties associated with measuring use, location, and quality compound the problem of

identifying water, assigning rights to it, and

selling it in an orderly market.

Physical Characteristics

The physical barriers to establishing a water

market stem from the fact that water changes

its form and location as it passes through the

water cycle. Water changes from solid to liquid

to gas and moves from high locations to low

locations. Because it is difficult to identify

specific units of water, the ability to assign and

enforce property rights is more limited than a

well-functioning market might require. Assigning clear title to atmospheric moisture may, for

example, interfere with assigning rights to subsequent rainfall. Also, most water users consume only a part of the water that comes to

them. Water used to generate hydroelectric

power may not be diminished (consumed) in

the process but will be moved in location. Even

water that is allocated to irrigation is not entirely consumed by plants; some seeps back

into the water channel as return flow. Often

the returning water picks up soluble salts and

other chemicals as it moves through soil and

back into streams. Thus, the return flow is

lower in quality than the water originally applied by the irrigator; it is now a different

commodity.

Multiple Uses

Some water is, and can only be used for a

single purpose, A farmer whose remote windmill pumps water for a flock of sheep is pumping single-purpose water. A municipality

pumps potable water to residential areas, and

much of this is not available for reuse at a later

time or in another plan. That portion of irrigation water consumed by growing plants cannot be recaptured for a second use. Many of

the major uses of water, however, are not consumptive uses and require only that water be

relocated or prevented from being relocated.

Recreation is a good example. Water flowing

through swift mountain streams or impounded

in the lake behind a major dam is used for

swimming, boating, fishing, and for its esthetic

appeal. The same water may be released in

order to generate electricity or maintain the

flow of a stream. While it is conceivable that

power users could organize and offer a price

for water used in generating electricity, it is
Ch. V—Institutions Affecting Western Agricultural Water Use . 137

——— — —

impractical to think of swimmers organizing

in order to purchase the “swimming rights”

that go along with a major water impoundment, The major (and minor) users of water

have interests in water, but no identifiable and

merchantable rights. Thus, the market fails to

allocate properly the water used for several

purposes.

Public Goods

A public good (sometimes referred to as a collective good) is a good that can be used “within

reasonable limits” simultaneously by many

people, More than this, no one person’s use detracts from the quantity available for other people to enjoy. A city park is a public good. One

person can use it without reducing the amount

of park-use time available to a second, third,

or tenth person. Many water uses have public

goods characteristics. Recreation is one example, navigation is a second (another boat can

go up the Columbia River), and flood protection, which is not a water use but is a kind of

water control that inhibits other uses, has

public goods characteristics.

Public goods are hard to value and hard to

price. One user may know that his/her use has

value and will bring an increase in utility, but

that user also knows that if someone else will

pay the bill, he/she can get the good for free.

The user will then be what is called a free rider.

Water-resource management is full of free-ride

problems, all of which contribute to the difficulty of organizing a well-balanced market in

which water can be purchased by potential

users and sold by those who no longer have use

for the resource.

External Effects

In economic terms, “externalities” are unintended consequences of an exchange or a production process. Some, such as the black-lung

disease suffered by thousands of coal miners,

are quite harmful. Others, such as the social

benefits stemming from an educated populace,

are valuable. All have one characteristic: if the

primary economic activity is altered, the external effects are altered, too. Water use is filled

with externalities. Towns grow up around irrigation projects. Aluminum is smelted near hydropower dams. Marinas are installed near reservoirs. Owners and participants of these external activities eventually develop a vested interest in the present allocation of water and can

act to impede the orderly functioning of a

market, Alternatively, the possibility of large

beneficial external effects may lead some industries or groups of individuals to ask for

water reallocations that are not consistent with

the highest and best economic use of the resource.

Recent Emergence of Scarcity

While the idea seems anachronistic, the true

economic scarcity of water is a relatively new

phenomenon in the arid West. Most croprelated agriculture in the West is enhanced by

irrigation, In early years, water was known to

be available, but large expenditures of capital

and labor were required to move it from mountains and rivers to arable land. The market,

then, was not for water but for the other resources needed to convey water. No market

was needed; there was generally enough water

for all reasonable uses.

These complexities—the physical characteristics of water, the multiple-use problem, water

as a public good, external effects, and the recent emergence of water as a scarce resource—

have impeded the organization and development of a well-functioning market. Even

though a market may help water allocation

among uses and users, no general market has

emerged. However, few economists will argue

against a market for water. An organized way

of trading or exchanging rights to this resource

could help ensure that the net social product

accruing from use of the resource would increase. This option has received increased attention at the State level and within some

Federal agencies.

Proponents of a market argue that if a market

does not exist, allocation of water will be left

to a governmental entity. Values will have to

be set so that priority of use can be established

to determine who will use the limited supplies

25-160 0 - 10 : QL 3
138 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

and government will do this through the political or legislative system instead of the market

system (see, e.g., Arizona’s legislative approach

to ground water reallocation, app. C). According to these proponents, government intervention has historically failed, especially when

trying to “correct” market failure; therefore,

the market system should be given an increased

opportunity to participate in the water allocation process. At the same time, a need for

special mechanisms and safeguards to protect

third parties and address other issues peculiar

to water is generally recognized.

Water Economics in a

Nonmarket Setting

Economics and economic reasoning play an

important role in the water-allocation decisions

made by individuals, groups of users, and governments. These decisionmakers often use surrogate or artificial prices to help guide decisions about who will have access to water and

how it will be used. In the absence of freely

operating markets, the government has often

been the decisionmaker and has established

regulations to guide water use. Many decisions

are reached only after determinations of the

value of water have been made and after these

values have been processed through an analytical process known as benefit-cost (or, frequently, cost-benefit) analysis.

Water Value

The economic value of water is relevant only

when explicit recognition is given to quantity, location, quality, and time of supply of the

water that is being evaluated—i. e., the hydrologic system must be considered in terms of

its interactions with climate, land, ecosystems,

and pertinent social and economic systems,

This intricate set of relationships is further

complicated by the highly variable nature of

water supplies and the importance of sequential uses (multiple uses) of water as it flows

from upper watersheds to its eventual destination in the sea or freshwater system. The value

of water is highly site-specific and varies directly with local conditions of supply and demand

for the resource in a particular use. Even

though these supply and demand conditions

do not often work themselves out in a market

setting, they form the basis for evaluations

using surrogate prices.

Benefit-Cost Analysis

Nonmarket resource-allocation decisions can

be made by using benefit-cost analysis (22).

Water-resource planning and decisionmaking,

in fact, represent two of the initial practical applications of benefit-cost analysis, and water

may still be the resource most widely allocated

on the basis of benefit-cost evaluations.

The benefit-cost framework is based on the

same principles found in any well-functioning

market system. It assumes consumer sovereignty and accepts the existing distribution of

purchasing power as given. The main analytical problem posed by this method is derivation

of a set of prices that are close estimates of undistorted market values when there is no clear

and well-articulated market value for the resource, Once’ determined, these prices can be

used as a guide in many water-allocation

decisions.

The process of estimating water values uses

the concept of willingness to pay as a basic indicator of economic value. Willingness to pay

reflects the dollar amount that a rational, fully informed consumer would be willing to

spend in lieu of doing without the commodity

or service. Willingness to pay for water is the

maximum amount a farmer would be willing

to pay for an extra acre-foot of irrigation water

or the maximum amount a group of fishing enthusiasts would be willing to pay to keep water

flowing in a mountain stream.

Varying from one water use to another, willingness to pay has an important influence on

demand for water. Some uses for water are

very intense, and people are willing to pay high

prices to satisfy this need. People are less inclined to pay high prices for less intense uses

of water. Household water falls into the former

group; water for boating falls into the latter.

Willingness to pay for water is also very re-
Ch. V--Institutions Affecting Western Agricultural Water Use ● 139

—

pensive to the quantity supplied. A household

can use only a given amount of water for cooking, washing, and watering the lawn. If more

is made available, willingness to pay for the

added water falls rapidly to low levels. Once

a crop has received “enough” irrigation water,

additional water may have a negative value. In

formal terms, significant increases in the suply of water for a particular use will have a

negative effect on the price (or value) of water

at the margin.

Methods of Valuing Water

A number of methods and conceptual bases

can be used to generate estimated prices for

water (boxes H and 1). No method is correct

or incorrect in the abstract. A particular method may be better or worse for a specific purpose. Many methods are correct or acceptable

in the restricted context of a local- or privateplanning decision but have limited applicability in valuing water from a national, long-term

policy perspective. This is because once a

method is chosen, it may yield different values

for water at different sites, depending on what

is being done with the water, when, and how.

Many estimates of water values appear in

both popular and technical literature. The

range of the empirical results demonstrates the

problems of trying to place values on water for

national water planning and policymaking.

One of the most complex problems is assigning values that are comparable in concept,

place, form, and time. The numbers below

summarize the results of a range of available

contemporary studies on water values. The

estimates are for 1acre-ft of water devoted to

a given use in a particular year. This type of

estimate is often referred to as a point estimate,

since it considers only the primary value of

water at a single point within a limited (given)

period in time. The studies from which these

numbers are taken are discussed in more detail

in appendix C.

The range of point-value estimates for Western, consumptive uses is (34):

In agriculture ... ... ... .. .$7 to $80/acre-ft

In industry ... ... ... .. .$0 to $1,600/acre-ft

In domestic use . . . . . . .$150 to $250/acre-ft

Box H.— Estimating Water Prices for Use in National Policy:

An Overview of Methods

Since the market does not price water directly, economists have developed several methods

to estimate water values:

●

●

●

●

●

Ex post statistical analysis of water-user behavior.—This method applies conventional statistical analysis to water-consumption patterns of various users. It has an advantage over

some other techniques in that it relies on actual willingness to pay for water.

Change in net income.–This procedure defines the value of water as the incremental addition to profits arising from an incremental application of water. Its results are somewhat

deceiving and often incorrectly applied.

Alternative cost.—Water is valued as costs saved by employing a water-intensive production plan rather than the most economically reasonable labor- and capital-intensive producing plan. This approach is sensitive to assumptions about such factors as technology and

interest rates.

Direct observation of markets.-This technique is rarely available or suitable for water-policy

analysis because of limited reliable markets.

Consumer surveys.—The value of water is calculated by asking consumers to place values

on changes in water supply or quality for certain public goods-such as recreation or pollution abatement. Estimates are potentially useful, but not always perfect substitutes for price.

SOURCE: R. Young, “Allocating the Water Resource: Market Systems and the Economic Value of Water,” OTA commissioned paper, 1982.
140 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Box I.—Economic Theory and Its Realization:

Some Technical Problems in Setting Water Values

Economic methods that estimate the value of water are designed to establish an artificial but

useful price for water in a particular use, at a particular site, and at a given time. The various

approaches depend on the concept of ceteris paribus, which means that other economic variables

are kept equal while the price of water is estimated. Although useful conceptually, these methods

are subject to several limitations, noted below:

●

●

●

●

●

●

Indirect effects resulting from water development.—When major water developments occur, other economic changes are generated at local, regional, and national levels. Water values

should be adjusted to reflect these perspectives.

Marginal v. total value.-Like other inputs in crop production (e.g., labor and fertilizer), the

value of water is its contribution to output. In setting water prices, the incremental use of

water and its effect on net product should be evaluated in lieu of weighing total water costs

against total output.

Changing water values during crop-production cycle.—The value of agricultural water varies

during the crop-production cycle. Emergency, short-term values, for example, are generally

higher than prices estimated for long periods of time. During a drought, a farmer maybe

willing to pay a high price for water. Conversely, if rainfall is plentiful or if the farmer chooses

not to plant a crop, the value of water is lower.

Comparing values in place, form, and time.—Water is a bulky commodity that may need

to be transported, treated, or stored before used. The investments needed to carry on these

processes should be considered in the water-valuation process.

Measuring quantity: water diverted or water consumed.—Obviously, the quantity of water

supplied is an important determinant of its cost. However, large differences in price will

result, depending on whether water values are calculated by the amount of water that is

withdrawn or whether water consumption rather than diversion is considered. No set rules

or conventions exist.

Annual rental value or future income.—Where a water user rents water annually, the value

of the water is limited to the rental payment. If, however, the user owns the water and has

a water right, its value is usually much higher and consists of its present value and its future

expected annual value. To reconcile these two concepts, interest rates and annual returns

should be considered in setting water values.

SOURCE ; R. Young, ’Allocating the Water Resource: Market Systems and the Economic Value of Water.” OTA commissioned paper, 1982.

The range of point-value estimates for Western,

nonconsumptive, instream uses is (34):

Hydropower generation .$3.30 to $30/acre-ft

Waste-load dilution . . . . .$1.30 to $15/acre-ft

Recreation ., . . . . . . . . ..$2.00 to $13/acre-ft

Fish habitat , . . . . . . . . . . Less than $1/acre-ft

Navigation , . . . . . . . . No acceptable estimate

Figures as varied as those above make it difficult to place a “true” value on this resource

and illustrate their limited use in evaluating national water policy. Instream use values pose

a special set of problems. While economic analysis and accounting procedures can be used

to value the products of instream uses, such

as hydroelectric power, it is difficult to develop

adequate values for the public uses (public

goods) of the water. This problem has become

more serious with the passage of time. Many

people now want to use water for such public

uses as recreation, boating, waste dilution, and

esthetic charm. However, the market does not

provide access to values for these uses, and

analysts have not been entirely successful in

developing surrogate values. The value of

water in instream uses is very hard to determine because of:

1. public goods problems associated with

many instream uses,
Ch. V—Institutions Affecting Western Agricultural Water Use ● 141

— — .

2. multiple-use problems, and

3. a lengthy national water policy tradition

that assumes that water used for hydropower and water used for navigation

should be free (34).

Economic Efficiency and the

Adoption of Water-Related

Agricultural Technology

Agricultural and nonagricultural users respond to economic conditions in their attempts

to become efficient. A farm unit will be economically efficient when it maximizes its profits (13). Efficiency occurs in relation to a

number of factors affecting farm operations.

In the last 20 years, new irrigation and engineering technologies have led to increased

engineering and economic efficiencies in irrigation. In almost all cases, the purpose of

such technology has been to conserve nonwater inputs—principally energy and labor, In

other words, becoming economically efficient

in irrigation may or may not have saved water.

In most areas the actual conservation of water

has been a byproduct of shifts in the production system caused by changes in the relative

prices of inputs (19),

This is not surprising, given the artificially

low price that most irrigators pay for water.

Even in the case of the Ogallala aquifer, increased pumping costs, not increased water

prices, have been responsible for the increased

marginal cost of water to a user. Also, subsidies

have reduced the cost of water to some users

and thus the amount the user could gain in the

sale of that water. This has allowed the levels

of demand for water to remain relatively high

and the incentive to sell for economic gain

relatively low. When water subsidies occur,

water use may be economically efficient from

the point of view of the individual user, but it

will not be efficient from society’s point of

view, since society (the subsidizer) pays some

of the individual’s costs.

Changes in Prices Paid for

Nonwater Inputs

Irrigated crop production is an energy-intensive activity in which the cost per unit of

output is greater than it is for dryland production in the same locale. The irrigation farmer

is thus very sensitive to energy prices. Table

35 indicates expected pumping costs per acrefoot of water, assuming a number of alternative

energy prices and water depths. Since the

1960’s, the price of natural gas has risen from

some $0.50 per thousand cubic feet to over $3

per thousand cubic feet—a sixfold increase in

pumping costs, In the 1960’s, it cost $6.07 to

lift an acre-foot of water 250 ft. By the early

1980’s, the cost for the same lift was $36.49 per

acre-foot,

Table 35.—Cost per Acre-Foot of Water to Pump at Alternative Depths,

Given Selected Natural Gas and Electricity Prices

Energy usea

Depth Natural gas Electricity Natural gas price ($/000 ft3

) Electricity price (¢/kWh)

(ft) (000 ft3

) (kWh) 0.50 1.00 1.50 3.00 5.00 0.01 0.03 0.05 0.10

$/acre-ft

50 . . . . . . . 5.36 154.2 2.68 5.36 8.04 16.09 26.81 1.54 4.62 7.70 15.40

100 . . . . . . . 7.05 259.6 3.53 7.05 10.58 21.16 35.27 2.60 7.80 13.00 26.00

150 . . . . . . . 8.75 265.1 4.37 8.75 13.12 26.24 43.73 3.65 10.95 18.75 36.50

200 . . . . . . . 10.44 470.5 5.22 10.44 15.66 31.31 52,19 4.71 14.13 23.55 47.10

250 . . . . . . . 12.13 580.0 6.07 12.13 18.20 36.39 60.66 5.80 17.40 29.00 58.00

300 , . . . . 13.82 681.4 6.91 13.82 20.74 41.47 69.12 6.81 20.43 34.05 58.10

350 . . . . . . . 15.52 786.9 7.76 15.52 23.27 46.55 77.58 7.87 23.61 39.35 78.70

400 . . . . . . . 17.21 892.3 8.60 17.21 25.81 51.62 86.04 8.92 26.76 44.60 89.20

aCalculated based on equations in D Kletke, R Thomas, and Harry P Mapp, Jr , “Oklahoma State University Irrigation Cost Program, User Reference Manual,” Oklahoma

State University, Department of Agricultural Economics Research Report P.770, 1978 Pressure was assumed to be 45 pounds per square inch (PSI) and pumping efficiency with natural gas 65 percent.

SOURCE: R Lacewell, “Economic Efficiency of Agricultural Water Use in the West, ” OTA commissioned paper, 1982
142 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

The overall effect of rising energy costs on

irrigation from ground water sources cannot

be determined from general estimates. Higher

pumping costs will probably mean less pumping and therefore less irrigation. Specific

results depend on the nature of the aquifer,

relative crop prices, and prices of other inputs.

Nevertheless, as the cost of pumping water increases relative to crop prices, there is an

economic incentive to apply less water per acre

of the crop.

In some areas, rising energy costs have

severely affected irrigated agriculture. A 450-

percent increase in natural gas prices between

1972 and 1975 caused cotton production to

diminish from 200,000 acres to 20,000 acres in

the Trans Pecos area of Texas (5). On the

whole, however, energy price increases are not

projected to have such dramatic effects on

cropping patterns [16].

Other input costs may affect the adoption of

water-related agricultural technologies as well.

In the late 1960’s and 1970’s, for example, use

of sprinkler systems expanded significantly in

the Western United States. This shift to a new

technology for applying water was seldom

made for the purpose of “saving water. ” Existing gravity-flow irrigation systems were

often converted to sprinkler systems in order

to save labor, as well as energy. In some cases,

sprinkler rather than gravity-flow irrigation

systems were installed to ensure either the efficient use of inputs such as chemical fertilizers or the use of a highly sophisticated and

intensive farming system (19).

Increased costs of inputs relative to crop and

livestock prices have implications for the structure of irrigated agriculture in the West in that

they will reduce net farm income per unit of

land. Thus, each farmer who maintains present agricultural practices may require more

land to maintain a given level of living, suggesting the need for larger farms. Irrigation

may not disappear from the West over the next

few decades, but the organization and structure of irrigated farming is likely to undergo

continual adjustment.

Changes in Prices Received

Profitability of irrigation is affected as much

by crop prices as by input costs. The level of

demand for water will be influenced by the

amount of crop in production and by the prices

received and expected for the crop. As crop

prices increase, potential profits will increase,

motivating the producer to plant more acreage

which in turn will increase the consumptive

use of water, assuming no increased prices for

the water. If significant increases occur in any

combination of actual water prices, delivery

costs, application costs, and perceived user

costs for water, crop prices received can have

a significant impact on the demand for water.

Moreover, if real prices for crops decline,

there will probably be some loss of irrigated

acreage. Even though the impact of crop prices

on the economic viability of irrigated agriculture may be as important as costs of production, there is one main difference: an individual

farm cannot influence crop prices, whereas an

individual farmer may be able to have some influence on costs of production by manipulating

technologies and improving management.

It is likely that changes in relative prices and

availability of nonwater inputs will continue

to influence the adoption of new technology

for water application. To foresee the impact of

new water-application technology on water

use, it will be necessary to have a sound

understanding of the farming system. Predictions about water use cannot be made by concentrating on the single input of irrigation

water, and public policies that ignore this fact

can be successful only as long as there is plenty of water to meet the demands for water.

Once water becomes more scarce relative to

demand, perceived costs to the water user will

have to increase to maintain a socially efficient

rate of water use, The rate of water use will

be determined by the entire farming system

and will involve the adjustment of rates of use

for many inputs in addition to the cost of water.
Ch. V—Institutions Affecting Western Agricultural Water Use 743

CONCLUSIONS

Decisions about water rights and their administration have developed along political

boundaries, usually the State unit. Water law

has developed to solve particular problems on

a sector-by-sector basis. For example, traditional western water law was designed first to

ensure miners a water supply. Then agriculture became the dominant sector of interest,

greatly influencing the law’s growth. In the

early 1900’s, municipal and industrial users

were granted certain rights under law. In the

1960’s and 1970’s, water-quality programs were

developed. As a result, application of traditional water law has raised difficulties among

users and among States sharing a common

body of surface or ground water. It has also

made water planning and management problems more severe as it developed without

regard to natural resource boundaries.

Markets for Western water have been slow

to develop. A number of reasons related to the

physical nature of the resource, public goods

characteristics, externalities, perceived

absence of scarcity, and social values have

been the cause. Allocations of water are made

through complex sets of institutions, legal

restrictions, and government regulations.

while these provide order and regularity to the

delivery of water, they do not always encourage or allow water to be put to its best use for

the general public interest.

Economics and economists play a central

role in evaluating water and water projects.

They use a number of tools to make determinations of the price or value of water. These tools

are very specific, and each can yield a flawed

estimate of water value. Moreover, the aggregation of estimates into a cohesive set of values

for a whole region or watershed may result in

errors. Care must be taken in the choice of

method, and all results, regardless of method

used in determination, must be accompanied

by explicit documentation of the assumptions

required by the analysis.

The United States and particularly its arid

and semiarid West is entering a new era with

respect to water and water use. As demands

for water for nearly all purposes increase and

as the true scarcity of the resource is recognized, pressure may mount to shift water to

new uses and users. The rules of economic efficiency support these arguments. Making such

changes, however, must be viewed in a broader

context than that of the primary or first use of

the water. whether the water is used for irrigation, navigation, recreation, or hydropower,

that water generates primary, secondary, and

tertiary outcomes. Transferring water to a new

use may have a profound effect on the supporting resources and on the people left behind as

well as those who benefit. Equity and fairness

concerns related to such effects on existing

users and new users increasingly will be raised.

In the past two decades, States have begun

to shift from the traditional water-allocation

role to one involving more water-resource planning and management. An active State role will

become increasingly necessary for resolving

growing conflicts over water use because of the

associated social effects of choices made. Federal institutions will also need a strong and

committed long-term role in water-resources

planning and management to protect national,

regional, and individual interests in this vital

resource.

1. Arizona v. California et al. Supreme Court of Management, No.1 (Boulder, Colo.: Westview

the United States, No. 8 Orig., Mar. 30, 1983. Press, 1982). ]n: Mann, 1982.

2. Ballard, Steven C., Devine, Michael D., et al., 3, Barkley, P,, “The Sustainability of Rural Non-

“Water and Western Energy: Impacts, Issues, Farm Economics in Water Dependent Agriculand Choices, ” Studies in Water Policy and tural Areas, ” OTA commissioned paper, 1983.
144 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

4.

5,

6,

7.

8.

9.

10,

11.

12.

13,

14.

15,

Brown, F. Lee, et al., “Water Reallocation,

Market Proficiency, and Conflicting Social

Values,” in Weatherford, Gary D., et al.,

Western Water Institutions in a Changing Environment, report to the National Science Foundation from John Muir Foundation, Napa, Calif.

(to be published by Westview Press, Boulder,

Colo., 1980). In: Young, Robert A., “Allocating

the Water Resource: Market Systems and the

Economic Value of Water,” OTA commissioned

paper, 1982.

Clarke, Neville P., Texas Agriculture in the 80’s:

The Critical Decade, Texas Agricultural Experiment Station B-1341, Texas A&M University,

1980.

Clyde, Edward W., “Current Developments in

Water Law,” Northwestern Law Review, No.

53, 1958-59, pp. 725-748.

Dewsnup, R., Jensen, D., and Quealy, M.,

“Selected Legal Constraints and Opportunities,” OTA commissioned paper, 1982.

Dewsnup, R. L., Jensen, D. W., and Swenson,

R. W. (eds.), A Summary-Digest of State Water

Laws (Washington, D. C.: National Water Commission, 1973).

DuMars, Charles, and Ingram, Helen, “Congressional Quantification of Indian Reserved

Water Rights: A Definitive Solution or a

Mirage, ” Social Assessment Manual (Boulder,

Colo.: Westview Press, 1980).

EZ Paso V. Reynolds, slip op. Jan. 17, 1983, doc.

No, 80-730 HB.

Finan, T., Downing, T., and Bennett, J., “Social

Impacts of Water Technology on Western Populations,” OTA commissioned paper, 1982.

Governor’s Commission to Review California

Water Rights Law, Final Report, Sacramento,

Calif., December 1978.

Heady, Earl O., Economics of Agricultural Production and Resource Use (Englewood Cliffs,

N. J.: Prentice-Hall, Inc., 1965). In: Lacewell,

1982.

Ingram, H. M., Martin, W. E., and Laney, N. K.,

“A Willingness to Play: Analysis of Water Resources Development in Arizona, ” Water and

Agriculture in the Western U. S.: Conservation,

Z?ealZocation, and Markets, G. Weatherford (cd.]

(Boulder, Colo,: Westview Press, 1982), pp.

137-1900

Ingram, H. M., Scaff, Lawrence A., and Silko,

Leslie, “Replacing Confusion With Equity: Alternatives for Water Policy in the Colorado

16.

17.

18.

19.

20,

21.

22.

23,

24

25,

26.

27,

28

29,

River Basin,” University of Arizona, Tucson,

unpublished, 1983.

Lacewell, R., “Economic Efficiency of Agricultural Water Use in the West,” OTA commissioned paper, 1982.

Mann, Dean E., “Politics in the United States

and the Salinity Problem of the Colorado

River,” Natural Resources Journal, vol. 15, No.

1, January 1975. In: Mann, 1982.

Mann, D,, “Changing Western Water Institutions,” OTA commissioned paper, 1982.

McConnen, R., “The Role of Economics in the

Adoption of Water-Use Technology in Agriculture,” OTA commissioned paper, 1982.

Moses, R. and Beaton, T., “The Initiation of

New Water Rights in the Western States,” The

Agricultural Law Journal, vol. 4, No. 2, summer

1982, pp. 153-178.

Ognibene, P. J., “Indian Water Rights Clouding

Plans for the West’s Economic Development,”

National Journal 14:44, October 1982, pp.

1841-1845.

Pearce, D. W., and Nash, C. A., “The Social Appraisal of Projects: A Text in Cost-Benefit

Analysis” (New York: Halsted Press, 1981). In:

Young, 1982.

Population Reference Bureau, “U.S. Population: Where We Are; Where We’re Going,” Population Bu)]etin, vol. 37, No. 2, June 1982, pp.

22-50.

Radosevich, G. E., Western Water Laws and Irrigation Return Flow, EPA-600/2-78-180 (Ada,

Okla.: U.S. Environmental Protection Agency,

1978).

Sporhase, et aZ. v. Nebraska ex rel. Douglas, Attorney General, Supreme Court of the United

States, No. 81-613, July 2, 1982.

Templer, O. W., Institutional Constraints and

Conjunctive Management of Water Resources

in West Texas, Project Completion Report:

OWRT Project No. A-029-TEX. Lubbock, Tex,,

1976.

U.S. Congress, Congressional Budget Office,

Public Works Infrastructure: Policy Considerations for the 1980’s (Washington, D. C.: U.S.

Government Printing Office, 1983).

U.S. Congress, Office of Technology Assessment, An Assessment of Oil Shale Technologies

(Washington, D. C.: U.S. Government Printing

Office, 1980).

U.S. Congress, Senate Committee on Environment and Public Works, Subcommittee on
Ch. V—Institutions Affecting Western Agricultural Water Use ● 145

—— — ——

30,

31.

Water Resources, “The Impact of the Supreme 32

Court Decision in Sporhase versus Nebraska, ”

hearing, 97th Cong., 2d sess. (Washington D, C.:

U.S. Government Printing Office, Serial No, 33,

97-H63, Sept. 15, 1982).

U.S. Department of Commerce, 1978 Census of

Agriculture (Seventeen Western States), Washington, D. C., 1981, In: Finan, Downing, and

Bennett, 1982.

U.S. General Accounting Office, Federal

Changes for Irrigation Projects Reviewed Do 34.

Not Lower Costs, PAD-81-07, Washington, D. C.,

Mar. 3, 1981. In: Mann, 1982.

U.S. General Accounting Office, Water Issues

Facing the Nation: An Overview, stud y

by the staff, GAO/CED-82-83, May 6, 1982,

Whittlesey, Norman K,, Buteau, Joane R. ,

Butcher, Walter R., and Walker, David, “Energy

Tradeoffs and Economic Feasibility of Irrigation Development in the Pacific Northwest, ”

College of Agriculture Research Center, Bulletin 0896, Washington State University, 1981.

In: Lacewell, 1982.

Young, R., “Allocating the Water Resource:

Market Systems and the Economic Value of

Water,” OTA commissioned paper, 1982,
——.——

Affecting

Technologies

Precipitation

and Runoff
.

Page

The Water Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

The Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

Weather Modification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

Surface Watershed Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Streamflow Forecasting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Chapter VI References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Table

Table No. Page

36. Variable Percentage of Surface Runoff From the Mountain Snowpack . . . . . . . . 150

37. Summary of the Nature and Extent of Alpine Disturbances

in the Western United States as of 1976 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

38. Potential Catchment Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

39. Summary of the Regional Irrigation Data and Benefits

in the 11 Western States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

40. Summary of the Computed Hydroelectric Energy and Other

Relevant Data by USGS Hydrologic Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

List of Figures

Figure No. Page

31. Vegetation Zones in the Mountains and Plains

of Western North America . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

32. Approximate Aptitudinal Ranges of Major Vegetation Types

in the Upper Colorado River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

33. The Spatial Distribution of Highland and Lowland Watersheds

Over the Western United States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

34. Average Runoff Hydrographic for Experimental Watershed. . . . . . . . . . . . . . . . . 162

35. Regions of Hydrologic Similarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

36. The Effect of Watershed Condition on Rainstorm Runoff and Erosion . . . . . . . 165

37. Catchment Surface With Butyl-Coated Nylon Water-Storage Bag. . . . . . . . . . . . . 168
—

Chapter VI

Technologies Affecting

Precipitation and Runoff

Most of the water used by agriculture in the

Western United States originates as precipitation, then runoff. The hope exists that large

amounts of additional water could be made

available by altering these processes a small

amount. A variety of technologies have been

developed either to increase or predict the surface runoff from watersheds of the Western

United States. These include augmentation

methods such as weather modification (“cloud

seeding”), watershed management through

vegetation removal or replacement, and

streamflow forecasting. Each of these has been

supported by Federal research, and interest in

each remains high.

This chapter illustrates the interrelated nature of these technologies and assesses the

degree to which they increase or manage precipitation and surface runoff for the region’s

agriculture. The chapter is based on the extensive research literature about the United States

and similar hydrologic environments throughout the world. A definitive regionwide assessment of these technologies cannot be made

here, Their effects on distant downstream

users may be difficult to measure, their results

may not be applicable to large geographic

areas, and few data syntheses exist. Considerable disagreement persists, then, regarding the

potential of these technologies as well as the

legal and institutional ramifications of their

application.

Box J

“If we lived in a desert and our lives depended on a water supply that came out of a steel tube,

we would inevitably watch that tube and talk about it understandingly. No citizen would need

to be lectured about his duty towards its care or spurred to help if it were in danger. Teachers

of civics in such a community might develop a sense of public responsibility, not only by describing the remote beginnings of the commonwealth, but also how that tube got built, how long it would

last, how vital the intake might be if the rainfall on the forested mountains nearby ever changed

in seasonal habit or amount. It would be a most unimaginative person, or a stupid one, who could

not see the vital relation between the mountains, the forests, that tube and himself. ”

SOURCE: Isaiah Bowman, “Headwaters Control and Use-Influence of Vegetation on Land-Water Relationships,” Proc. Upstream Engin. Conf. Washington, D.C.,

pp. 76-95, 1937.

THE WATER SETTING

In the Western United States, a watershed mates, geology, soil and vegetation types, and

may be as large as that of the Missouri River land use practices. Even the smallest waterbasin, with a surface area of at least 500,000 sheds are seldom homogeneous in all of these

square miles (mi2

), or as small as an ephemeral factors.

tributary to that river, with a surface area of

only a few tens of acres. Watersheds in the Water may leave a watershed in a variety of

Western United States, at their largest geo- ways. The most obvious is surface runoff as a

graphic scale, encompass a wide range of cli- river or stream. Water also may leave a water149
150 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— —.-.

shed by percolating to ground water. The extent to which this occurs is dependent on the

ability of the soil and rocks of the basin to

transmit water. Over much of the Western

United States, the primary means by which

water leaves the watershed is by evapotranspiration (ET). ET is generally greatest in the arid

and semiarid portions of watersheds and least

in high-altitude mountain watersheds. Thus,

ET may account for almost all of the precipitation falling on a watershed in an arid portion

of the Lower Colorado River Basin, while it

may account for only a small fraction of the

precipitation falling in an alpine environment

at the headwaters of that river.

Each year, an estimated 1.5 billion acre-ft of

water are added by precipitation to the water

supplies of the Western United States. Of this

amount, approximately 500 million to 550 million acre-ft form the surface runoff of the region, 50 million acre-ft enter into the ground

water reserves, and the major portion is returned to the atmosphere by evaporation or

transpiration from vegetation. The bulk of the

surface runoff is derived from the melting

mountain snowpack, which produces an estimated 70 percent, or 350 million acre-ft, of the

runoff of the region (table 36).

Table 36.—Variable Percentage of Surface Runoff

From the Mountain Snowpack

Estimated snowmelt fraction of the total annual surface

runoff for those Western States where melting mountain

snowpack is the principal source of surface runoff.

State

Arizona . . . . . . . . . . . . . . . . . . . . .

California . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . . . . . .

Oregon. . . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . . . . . .

Washington. . . . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . . . . . .

Snowmelt fraction of

total annual streamflow

0.74

0.73

0.73

0.67

0.70

0.65

0.71

0.67

0.74

0.67

0.74

0.70

SOURCE P Castruccio, H. Loats, D. Lloyd, and P Newman, Application Systems

Verificatlon and Transfer Project, Volume VII: Cost/Benefit Analysis

for the ASVT on Operational Applications of Satellite Snow-Cover

Observations, National Aeronautics and Space Administration

Technical Paper 1828, 1981

Channeled surface runoff, as occurs in rivers

or streams, is of three major types: perennial

runoff, which flows throughout the year; intermittent runoff, which occurs each year during

certain seasons; and ephemeral runoff, which

only occurs following an event such as a heavy

rainstorm, While both intermittent and ephemeral runoff contribute at times to the flow of

the perennial rivers and streams of the region,

they do not constitute a dependable water-supply source, except for specialized local uses.

Intermittent and ephemeral runoff characterize

much of the valleys and plains of the Western

United States, while the perennial rivers almost

always have their headwaters in the mountain

ranges of the region. The amount of ET will

be determined by the amount of available energy required by this process, the seasonal

distribution and amount of precipitation, and

the nature of density of the vegetal cover,

The ratio between the amount of precipitation falling on a watershed and the amount

leaving the watershed as surface runoff determines the “runoff efficiency” of that watershed. As the runoff efficiency increases, greater

amounts of precipitation become surface runoff. Runoff efficiency for any given watershed

is determined by complex interactions among

precipitation, evaporation, and soil-moisture

recharge. The demands of evaporation and soil

moisture recharge, which must be met before

any surface runoff can occur, are relatively

constant from year to year, while precipitation

may be variable. The interactions among these

hydrologic elements are complex and generally

small percentage changes in a single element,

such as precipitation, will not translate directly

into a proportional change in surface runoff.

Runoff efficiency in the Western United States

varies greatly, from as little as 10 percent in

a hot desert environment (where most of the

precipitation rapidly evaporates) to as much as

90 percent in a humid maritime climate. Technologies designed to increase surface runoff by

changing some element of the hydrologic cycle to increase runoff efficiency must be considered in terms of the wide range of hydrologic regimes which characterized the region.

Any volume of additional runoff produced

by modification of a particular watershed will
Ch. V/—Technologies Affecting Precipitation and Runoff . 151

.

eventually move through the entire river system to the sea or ground water, or be removed

by evapotranspiration. The ability to measure

any increased volume by the application of

technology will diminish as one moves farther

from the point of application and as the water

is incorporated into the normal, increasing volume of the river system. Thus, the impact of

the application of any watershed-management

technology that produces

runoff will be most easily

point of application.

Information on impacts

agement technologies that

additional surface

measured near the

of watershed-manattempt to increase

usable runoff or to improve management of

that runoff has been derived largely from experimental watersheds, These technologies include: 1) precipitation augmentation by weather modification (cloud seeding), 2) removal or

replacement of vegetation to reduce evapotranspiration or to increase snow captured onsite,

3] management of surface water runoff through

modification of the surface permeability and

landscape to store water or direct it to selected

areas, and 4) water-supply forecasting, The impacts of any technology designed to alter the

hydrologic cycle within a watershed will be affected by the basin’s preexisting water regime,

the relationship among the elements of the basin’s hydrologic cycle, and the portion of the

watershed to which they are applied.

It is useful to consider the major elements

of a watershed in order to understand the kinds

of specific technologies that might be applicable to increase surface runoff or to improve the

ability to manage or forecast the natural or

modified runoff. A number of classification

systems have been proposed. For timbered watersheds, the U.S. Forest Service has proposed

a classification scheme based on the dominant

vegetation present (e. g., 14). A similar concept,

based on vegetation type, has been used to describe rangeland watersheds where brush or

grasses, rather than timber, are dominant (e.g.,

11), For development of streamflow runoff forecast models, classification is commonly based

on the dominant form of precipitation—i.e.,

rain or snow—while weather-modification

technologies are generally classified in terms

of the dominant meteorological process controlling precipitation. Fundamentally, each

technology has developed its own approach to

the classification of watersheds without reference to the other relevant watershed-management technologies.

To compare technologies that modify or forecast runoff from watersheds, a simple but useful classification based on altitude above sea

level and major topographic features was used

in this assessment. In this scheme, watersheds

of the Western United States may be viewed

as being either “highland” watersheds, those

associated with the mountain ranges of the region, or “lowland” watersheds, which are

found primarily in the adjacent valleys and

plains. While such a system does not completely describe the range of application for any

single technology, it enables comparisons between the technologies considered. In addition,

it corresponds approximately to the most recent classification scheme proposed by the

Forest Service for delineating the ecoregions

of the United States (3).

The highland-lowland classification used

here is based primarily on major terrain features and vegetation types. In essence, the

highland watersheds are located in mountain

ranges and have a vegetative cover characterized by alpine tundra at their highest elevations

and montane coniferous forests at lower elevations, Lowland watersheds consist of valleys

and plains adjacent to these mountains. Some

conifers, such as pinyon-juniper stands may be

present in the lowlands, but the dominant vegetation is deciduous trees or brush and grasslands (figs. 31 and 32).

Latitude and position on the continent affect

the type and density of the vegetative cover in

both types of watersheds. The highland watersheds are marine, as in the Pacific Northwest;

mediterranean, as in California; or continental, as in the Rocky Mountains. Lowland watersheds are prairie, in the eastern portion of the

Western United States; steppe, between the

Coastal Ranges and the Rocky Mountains and

immediately to the east of the Rocky Mountains; or desert, in the Southwestern United

States (fig, 33). In each case, a distinctive
152 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

-— —. —

Figure 31 .—Vegetation Zones in the Mountains and

Plains of Western North America

This diagram shows general conditions that might be

expected in the Central Rockies of Utah. To the north, south,

east, or west of this region, vegetation may change. For

example, to the north and east, the pinyon-juniper zone is absent; in the east, an oak-mountain mahogany zone IS present

between the grassland and northern conifer forest.

SOURCE Biological Sciences Curriculum Study, Biological Sciences: An ECOlogical Approach, BSCS Green Version, 4th ed (Chicago Rand McNally

& Co 1978)

vegetation type and hydrologic regime have

developed in response to precipitation and

temperature patterns (3),

A highland-lowland distinction is useful in

relating both the form and seasonal hydrologic

behavior of water and the varied environments.

The highland portion of each watershed is cold

and humid relative to the surrounding lowlands. Much of the annual precipitation falls

as snow during winter and becomes liquid water for runoff, evapotranspiration, or infiltration into the soil during spring and summer,

The lowland portion of each watershed is

warmer and drier. Rain is much more common

here and snow melts more quickly during the

winter or early spring than in the highlands.

Snow does not accumulate to the depths common in highland areas. Generally, the amount

of precipitation of any form decreases with

decreasing altitude.

Highland watersheds generally give rise to

perennial streams or rivers. Lowland watersheds are characterized more often by either

intermittent or ephemeral runoff, While both

forms of runoff are variable to some extent,

both seasonally and annually, perennial

streams will be less so. In addition, perennial

streams and rivers are more likely to be regionally significant in their importance as watersupply sources, while intermittent and ephemeral streams are more likely to have a local, sitespecific importance, Technologies to affect surface runoff must be designed with these characteristics in mind.

Figure 32.—Approximate Aptitudinal Ranges of Major Vegetation Types in the Upper

Colorado River Basin (water resources region 14)

Highland

watersheds

Lowland

watersheds

The diagram shows the various ecological communities contained within highland and lowland watersheds.

SOURCE F Branson, G Gifford, K Renard, and R Hadley, Range/and Hydrology, Society for Range Management, Range Science

Series No 1 (Dubuque, Iowa” Kendall/Hunt Publishing Co , 1981)
—————

Ch. VI—Technologies Affecting Precipitation and Runoff . 153

———

Figure 33.— The Spatial Distribution of Highland

and Lowland Watersheds Over the Western United

States

Highland watersheds are primariIy mountains and consist

of northern conifers or alpine tundra biomes. Lowland watersheds are characterized by a variety of grasslands or shrub

ecological communities

1

I 1

Highland watersheds (alpine tundra

and northern conifer forests)

Lowland watersheds (Pinyon-juniper,

v

grasslands, desert, etc.)

The major biophysical environments that

may be present in combination or singly in a

watershed are the: 1) alpine tundra, 2) montane

forest, and 3) grasslands or shrublands. The alpine tundra is that portion of a mountain range

above timberline (the upper limit where tree

growth occurs) and is found in most major

mountain ranges of the Western United States.

The montane forest environment extends from

the timberline at the lower edge of the alpine

zone to the base of the mountain. Grasslands

and shrublands exist on the low-altitude plains

and hills extending out from the foot of the

mountains. Across these three environments,

various land use practices, including timber

harvesting, rangeland agriculture, or crop production, mav be practiced in some combination. In general. the annual snow/rain ratio and

runoff efficiency will decrease from the alpine

environment to the grasslands.

The choice of an appropriate watershedmanagement technology to affect surface

runoff is influenced by all these watershed factors. The appropriate technology should be

designed for the principal form of precipitation and the percent of surface area in each of

the major biophysical environments affected.

Transition zones may occur where the snow/

rain precipitation ratio or biophysical environments are mixed. In these areas, no single

technology may be clearly preferred, Generally, technologies that have been developed to affect surface runoff for onsite or offsite use are

specific to a particular set of characteristics in

highland or lowland watersheds.

The highland and lowland watersheds, primary water-producing areas of the West, largely are on public lands, As such, Federal agencies responsible for managing these lands will

play an important role in affecting the future

of water use on arid/semiarid lands, whether

through active or passive involvement, Pursuant to their multiple-use responsibilities,

these agencies have the mandate to include water resources and water-resources management

within their multiple-use objectives, The multiple-use concept already is embodied in a number of Federal laws including the Multiple-Use,

Sustained-Yield Act of 1960 (Public Law 86-

517) and the Federal Land Policy and Management Act of 1976 (public Law 94-579). Existing

multiple-use statutory guidelines prohibit optimization of a single measurable resource (e.g.,

timber and cows) at the expense of less quantifiable uses (e. g., watershed and recreation),

and they forbid practices that impair continued

land productivity (9).

25-160 0 - 1 1 : QL 3
THE TECHNOLOGIES

Weather Modification

Introduction

Weather-modification technologies, often

called “cloud seeding, ” owe their scientific

beginning to one initial experiment that demonstrated that an artificial ice-nucleating agent

such as solid carbon dioxide induces the formation of ice crystals in air supersaturated

with water vapor with respect to ice (19). The

ice crystals grow quickly to precipitable size

and fall from the cloud as precipitation that

might not have occurred naturally. All modern

cloud-seeding technologies have developed

from this discovery.

Cloud seeding works in two ways. First, artificial nuclei may stimulate small cloud particles to coalesce. Second, cloud seeding with

ice nuclei or solid carbon dioxide (dry ice) may

induce freezing and cause the production of
Ch. VI—Technologies Affecting Precipitation and Runoff ● 155 —

large numbers of ice particles, which proceed

to grow to precipitable size. In the first case,

known as “warm seeding,” waterdrops maybe

introduced into a cloud to start a process that

might otherwise take longer. Because modifying a cloud might entail a substantial mass of

water in the form of individual drops, finely

divided salt or a water-attracting chemical mist

is usually used instead. In experiments, for example, a concentrated water solution of ammonium nitrate and urea has been sprayed

from an aircraft into a cloud in the form of

droplets about 0.20 millimeters (mm) in diameter. Within a minute, the nitrate and urea

droplets grew by gathering condensation from

the vapor to a ().5()-mm size, a factor of 15 in

mass. The 0.50 mm drops were large enough

to start a process that may have produced

drops 5 mm in diameter only 20 minutes later,

The second method, seeding by dry ice or

silver iodide, requires that the clouds being

seeded be at temperatures below freezing. If

dry ice is used, it has the effect of inducing a

massive, rapid cooling that freezes the supercooled water droplets in the cloud. In contrast,

silver iodide particles are good nuclei for ice

formation because of the close resemblance of

their crystal structure to that of ice (21), Whichever seeding material is used, the result is the

production of ice crystals that, it is argued, will

increase the precipitation efficiency of air

masses known to contain significant amounts

of supercooled water droplets.

Water-attracting particles and ice nuclei can

be introduced into the air mass in different

ways. In the first field experiments, dry ice was

dispersed from a small airplane (19) and silver

iodide was generated at the ground. Groundbased generators are considered to be effective

in the absence of a strong temperature inversion, which inhibits convection, and in mountainous terrain, where orographic processes

are generally present. Silver iodide is also often

released from aircraft with the aim of placing

the nucleating agent directly into selected portions of clouds containing liquid droplets.

Cloud-seeding technologies have been tested

primarily in two major air mass types: 1] winter

orographic air masses, and 2) summer cumulus

air masses. Orographic air masses are those

that are forced to rise by their passage across

mountain ranges and are often associated with

major winter frontal systems. Cumulus air

masses are those that commonly form during

the summer months as warm moist air rises

owing to surface solar heating, though they

may also occur in post-frontal situations in

winter, The seeding of orographic air masses

generally is undertaken to increase the amount

of snow stored in the highland mountain watersheds during the winter. Seeding cumulus

clouds to increase precipitation has the primary objectives of increasing soil water, of inhibiting hail formation in lowland watersheds

during the summer, or for direct crop rainfall

in areas of small grains, corn, and so}’bean

production.

APPLICATION TO MOUNTAIN CLOUD SYSTEMS

Three decades ago, Bergeron (4) concluded

that the main potential for causing considerable artificial precipitation might be found within certain types of air masses as they are forced

to rise over mountain ranges. This conclusion

was based on the argument that there was more

water in the clouds than was being released as

precipitation. Considerations assumed a steady

and often substantial formation of liquid water

for an extended period of time in a fixed location and the probable accumulation of “releasable but unreleased” cloud water at levels with

temperatures below 00 C. Generally, the basic

criterion for determining whether or not a

seeding potential exists is the natural precipitation efficiency of the clouds—orographic or

otherwise. The measure of precipitation efficiency is the percentage of the total water in

the cloud system that actually reaches the

ground. Seeding would not be required where

the efficiency is high, On the other hand, seeding may or may not be of value when the natural precipitation efficiency is low.

While precise numerical values are difficult

to achieve, a useful basis for evaluating precipitation efficiency is the comparison between

water removal by growth of ice crystals and

the supply of liquid water in the cloud. To illustrate this idea, the following processes have
156 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

been compared for a broad range of cloud temperatures: the average rate of formation of liquid water, the average rate of consumption of

this cloud water by ice-crystal growth that

would occur from natural concentrations of

primary ice crystals, and actual average rates

of precipitation observed at ground level. Studies show that, with cloud-top temperatures of

–20 o C or colder, the observed actual precipitation corresponds closely to the rate at which

liquid water becomes available in the clouds.

In the main, such clouds should have a high

natural precipitation efficiency with little corresponding potential for seeding.

When cloud-top temperatures are warmer

than –20 0 C, natural precipitation efficiency

should be low. For these cases, observed values

of ground precipitation are, in fact, much less

than the average amount of condensate available. A potential for seeding can exist in these

cases.

APPLICATION TO CUMULUS CLOUDS

In summer in the Western United States, precipitation very often occurs from cumulus

clouds. These clouds form as warm moist air

rises from the heated earth and are not necessarily associated with large-scale frontal systems. The natural precipitation efficiency of

these isolated clouds is quite low. Even the

largest clouds—those reaching thunderstorm

size—exhibit precipitation efficiencies of only

about 10 percent. The important question is

whether isolated cumuli constitute promising

targets for artificial nucleation by virtue of their

comparatively low natural precipitation efficiency. A major difficulty in assessing possible modification potential is the enormous natural fluctuation in all variables.

In determining seeding potential, it has

proven useful to subdivide all cumulus clouds

into two types: first, those having typically 50

to 100 droplets per cubic centimeter (cm3

) and,

second, those with 400 to 1,000 droplets per

c m

3

. As the total cloud liquid-water contents

are not greatly different for the two types, the

average droplet radius must be about twice as

great in the first as in the second. The clouds

with larger droplets have a more rapid coalescence process because fewer collisions will be

required to produce a raindrop. In cumuli containing small droplets, the coalescence process

would have to operate for a much longer time

in order to develop raindrops in sizes large

enough to precipitate. On the basis of this, ice

nucleants probably offer less potential for stimulating precipitation in cumuli containing large

droplets, for such cumuli can, and evidently

do, develop rapidly to the precipitation stage

naturally. On the other hand, the same picture

suggests that cumuli containing many small

droplets might be more readily modified artificially by accelerating cloud particulate

growth by seeding. This assumes that these cumuli have cloud-top temperatures of less than

00 C and that natural ice-forming nuclei are so

deficient that a substantial part of the cloud

water is supercooled,

Although this idea seems simple, there have

been few experiments that have demonstrated

the effect in the field. Early observational programs, such as those in Australia, gave clearcut results (23), whereas a U.S. study was inconclusive. It is estimated that an operational

cumulus cloud-seeding program (e.g., in the

high plains) would require a minimum of 10

years, starting from existing knowledge based

on a focused and adequately supported effort

(25). *

Several States, local government agencies,

and private utility companies now are engaged

in weather-modification projects in the Western United States. In addition, ongoing and

planned large-scale cooperative programs exist under Bureau of Reclamation sponsorship

as well as jointly funded cooperative programs

with the National Oceanic and Atmospheric

Administration (NOAA) (22).

As of 1982, the States in which seeding projects were being conducted were California, Nevada, Utah, North Dakota, and Texas, with

planning under way in Colorado, Oklahoma,

—

*Seeding very large cumulus and cumulonimbus clouds has

been undertaken in Kenya, U. S. S. R., Switzerland, France,

Canada, and the United States in attempts to decrease damage

from hail. Some of these programs claim 30- to 80-percent

decreases in hail damage to crops. Others have observed no

effects.
—

and Arizona. There are 13 independent pro

Ch. VI—Technologies Affecting Precipitation and Runoff . 157

. — .- . .—

ect areas in California, 4 in Nevada, 3 in Utah,

3 in North Dakota, 2 in Colorado, and 1 in

Texas. Most, if not all, of the programs west

of the Continental Divide are conducted in high

mountainous areas where snowpack augmentation is the goal. The programs east of the

Divide are designed for rain enhancement and/

or hail suppression efforts (22).

SEEDABILITY POTENTIAL

For the Western States, the potential of

weather modification for augmenting water

supplies is related, in part, to the number of

opportunities available for a seeding operation.

The fall, winter, and spring months yield between 30 and 50 precipitation events in which

opportunities may exist to carry out a modification operation. An event is defined as a storm

that is expected to last 6 hours or more and to

yield measurable precipitation. Some of these

storm events may last up to 3 days. The potential for seeding a storm to produce additional

precipitation depends on the existence of supercooled liquid water in the clouds of that

storm. The cloud must contain liquid water at

temperatures below freezing for the ice phase

processes to be effective. If there are only a few

“seedable” events available per season at any

given location, considerations of economics

may become crucial in deciding on the benefits

to be accrued from this opportunity-limited

situation (22).

“AREA OF EFFECT” PROBLEM

One of the most important issues in weather

modification today is the determination of the

‘‘area of effect” of operational and/or research

cloud-seeding programs. In its fullest sense,

area of effect encompasses not only the microphysical and dynamic aspects of cloud-seeding

effects but questions of water budgets, optimization of seeding technology, and State and international boundary issues.

In particular, it is important for the research

community to determine the impact (if any) of

seeding programs in one State on the water

supplies of an adjacent State or area. It is well

known that in a number of weather-modification projects, there have been indications of noticeable effects outside the “intended target

areas, sometimes at surprisingly large distances, especially in the downwind direction.

The programs in Switzerland, Israel, and Colorado, in particular, have been cited as examples (22),

RIGHTS TO USE Of AUGMENTED WATER

Perhaps no other aspect of weather modification is as perplexing as the concept of ownership or use rights regarding the water generated by cloud-seeding projects. No body of law

exists to deal with such problems; laws were

created to deal with surface waters and were

later expanded to cover ground water. Stretching these earth-bound laws to cover atmospheric moisture that does not confine itself to a

watershed, let alone to political boundaries, is

a difficult process (10).

The principal questions for weather modifiers relate to the share of “new” water that

might go to each modifier and the verification

of water-use rights based on weather-modification activity. The questions become increasingly complex as possible variables are considered—Does a senior rightholder downstream

have any rights to the “new” water i n d r y

years? IS a Federal water right created for

water that the U.S. Government generates

through its cloud-seeding efforts? Answers to

questions such as these will depend on how the

new water is classified. Classification hinges

conceptually on identifying the water as ‘‘developed” water—i.e., water not previously a

part of the natural yield of a river basin but

rather additional water made available from

the weather modification activities.

It is essential that the weather modifier be

able to prove that additional runoff has actually

been developed before securing a right to its

use. It is likely that the procedure would require the modifier to demonstrate that a specific quantity of water in the stream would not

have been there under normal conditions—i,e,,

without cloud seeding,

The problem is narrowed to that of “proving” a quantifiable increase over the natural
158 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

streamflow. Eventually, the technology may be

developed to enable definitive and accurate

measurement of such increases, but it is not

possible now, as discussed earlier, and a great

deal more knowledge must be available before

anyone can define how much water is developed from cloud seeding. Until the science of

weather modification offers some concrete

proof of its effectiveness and measures this effectiveness, any precipitation so produced almost certainly will be considered part of the

natural yield and will be distributed in accordance with established rights.

Assessment

Compared to other augmentation technologies such as evaporation control or interbasin

transfer, the technology of weather modification can be viewed as an economically attractive method for bringing additional water into

water-short regions of the Western United

States. However, the viability of the technology rests on the occurrence of suitable atmospheric conditions in these regions. Drought

years are the result of low rainfall, an indication of a low frequency of precipitating cloud

systems. Weather-modification technology depends on the availability of suitable cloud conditions for its application. Consequently, the

high, mountainous regions of the Western

United States probably offer the greatest and

most reliable potential for precipitation augmentation because these regions receive the

winter snows and thus provide the springtime

runoff water supplies to agricultural lands and

to ground water. These highland regions are

cooler for longer periods of time than lowlands

and thus provide a longer season for accumulation of snow and storage of water as snow.

In general, the major difficulty faced in

weather-modification technologies is the inability to detect statistically significant changes

in either snowpack water-equivalent depths,

snowmelt runoff, decreased hailstone size, or

increased rainfall at the ground surface. While

fairly substantial increases in the volume of

water stored in the winter snowpack have been

claimed, these claims have been challenged by

other researchers. In at least one case (“ Project Skywater, ” San Juan Mountains, southwestern Colorado), after a number of years of experimental seeding operations, the Bureau of

Reclamation concluded that a slight, but statistically insignificant, decrease in streamflow

had occurred.

These discrepancies may be due, in part, to

an incomplete understanding of snow-crystal

or hailstone growth and the precipitation processes involved, Also a contributing factor is the

incomplete understanding of the processes affecting snowpack accumulation, melt, and runoff in the mountain environment. There are

problems in selecting suitable air masses and

in understanding both the physical processes

that control the natural production of ice nuclei

and the efficiency of the nucleation process.

Similarly, the way in which seeding materials

are dispersed in air masses, the origin and location of supercooled water in air masses, and

the effects of small changes in the purity of

seeding agents need further study. The definition of useful verification standards is another

major area needing attention,

The most valid line of research, in light of

these problems, may involve studies of air mass

characteristics to understand better the nature

and behavior of an air mass prior to and during a seeding experiment. Attempts are now

underway to develop more objective verification procedures based on properties of the

deposited snow rather than on statistical relationships between precipitation and runoff.

More sophisticated studies of the mountain

snow accumulation and runoff regimes must

be an integral part of future cloud-seeding

experiments.

The environmental effects of increased precipitation as a result of cloud seeding have been

examined on a number of occasions. Shortterm environmental effects are discussed in the

Colorado River Basin Pilot Project Final Environmental Statement, The Project Skywater

Programmatic Final Environmental Statement,

and the Sierra Cooperative Pilot Project Environmental Assessment (22), These studies conclude that the incremental increases in precipitation over the short term involved with cloudseeding research programs do not have signifi-
Ch. VI—Technologies Affecting Precipitation and Runoff ● 159

cant adverse impacts on environmental-ecological systems. Incremental increases are usually within the historic natural variability of

seasonal and annual precipitation in the study

areas (22). As additional information and experience have become available, scientific concerns about potential long-term negative environmental impacts caused by precipitation

augmentation have eased (22).

Surface Watershed Management

While precipitation augmentation through

cloud seeding may be considered a watershedmanagement technology, current use of this

term restricts it to those practices designed to

modify the volume or timing of surface runoff

by surface modifications, such as vegetation

manipulation. This section discusses technologies that attempt to increase surface runoff

for offsite use or to retain precipitation onsite

to promote plant growth and stabilize the soil.

The technologies will be discussed in the context of the watersheds they affect.

In general, technologies that have been developed to affect surface runoff by surface

modification are site-specific in both highland

and lowland watersheds. Transitional zones

also exist where the hydrologic environment

is a mixture of montane forests and alpine tundra (at the upper limit) or grasslands and brushlands (at the lower). In addition a mixture of

precipitation can occur in each watershed type,

depending on elevation. In transition zones,

technologies from either highland or lowland

watersheds may be applicable, and careful

evaluation is necessary for selecting the appropriate technology for a particular transition

zone.

Highland Watersheds

Typically, highland watersheds are composed of two biophysical environments or

zones: the unlimbered alpine belt above timberline and, below this, the montane forests.

These two zones are commonly separated by

a transitional zone which most workers refer

to as the “subalpine. ” Surface runoff, ground

water recharge (where it occurs), and the liquid

— — —

water necessary for plant growth is supplied

largely by the melting of the snowpack that

forms during the winter.

Highland watersheds play a vital role in supplying water to rivers in the Western States.

The percentage of total surface runoff passing

annually through a river or stream which originates from the melting of the snowpack of

highland watersheds varies widely; however,

for the 11 westernmost States, researchers estimate that between 70 to 75 percent of the total

annual surface runoff of the region originates

from this source (e.g., 7).

In addition to their importance as wateryielding areas, highland watersheds have many

other uses. Domestic and wild animals graze

in the grasslands of the alpine belt and in

meadows within the montane belt. In the montane forests, commercial timber production is

the ‘most important. Other potential or actual

uses include recreation, wildlife habitat and,

locally, mineral extraction.

THE ALPINE ZONE

Introduction.—The alpine zone is a relatively cold, wet environment, where precipitation

falls as snow during every month of the year

and snow deposits persist throughout the year.

Precipitation amounts, which commonly increase with elevation, are highest in the alpine

zone. Coupled with the low amounts of evapotranspiration and infiltration, the alpine

regions produce the highest runoff efficiency

(the ratio between precipitation inputs and

streamflow) in the West,

The snowcover of the alpine zone is unevenly

distributed, a result of high winds that often

accompany the storms moving across the region and the rugged topography, which traps

blowing snow. Large areas blown completely

free of snow alternate with deep snowdrifts

that form in sheltered sites, The concentration

of snow into these snowdrifts causes snowmelt

to be delayed relative to areas where snow deposits are more uniform. This, in turn, delays

runoff until later in the season than is the case

with the snow cover at lower altitudes. It is this

storage and delay of snow melt runoff until the
160 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

warmer summer months, when demand in the

lowlands is at a maximum, which contribute

to the hydrologic importance of the alpine belt,

The alpine zone is not uniformly distributed

throughout the mountain ranges of the Western

United States. Estimates of its total surface area

are difficult to make. One estimate places the

total alpine acreage in the West at approximately 10 million acres (20), or slightly less than 10

percent of the acreage of montane forests in

the region. A more recent estimate suggests

that the actual area may be closer to 8 million

acres.

Hydrologic studies in the alpine region of the

Western United States have been scattered and

sporadic, Studies specifically dealing with aspects of the hydrologic cycle as they influence

snow accumulation, melt, and runoff in the alpine belt have been undertaken by only a few

investigators, and only broad generalizations

are possible from these studies.

Existing research indicates that the alpine region is naturally efficient in producing runoff

and constitutes an important water source for

the region. For example, in Colorado, estimates

indicate that the alpine belt, which comprises

about 3.5 percent of the surface area of the

State, produces approximately 20 percent of

the State’s surface runoff (20). In Utah, it is

estimated that 10 percent of the State’s highest elevation areas yield 60 percent of its runoff;

this area and the next lower 15 percent of the

surface area, account for 90 percent of the total

runoff of the State (20).

Relatively few technologies have been proposed for manipulating runoff and water yield

in the alpine belt. In part, this is because of the

difficulties of access to and movement in an

environment that generally is cold, windy, and

snow covered during much of the year. Additionally, research in this environment has had

little funding support from the public and private sector, owing to the apparent lack of management opportunities. Studies to date have focused primarily on the installation of snow

fences to trap blowing snow, to increase local

snow storage, and to reduce water losses from

sublimation during wind transport (16). Other

studies have looked at the possibilities of rehabilitating parts of alpine watersheds that

are disturbed by other activities, such as mining (13).

Assessment.—A major limitation for application of snow-fencing technologies in the alpine

zone is the scarcity of favorable sites for installation of fences. Suitable sites constitute a

small fraction of the total alpine area (6).

Research indicates that some potential exists

for rehabilitating many presently disturbed alpine sites, but only more intensive management practices can help reduce the impacts of

future disturbances (13), Severely affected sites,

such as abandoned or active mine dumps, generally require intensive revegetation and rehabilitation efforts. The success of these efforts requires an extensive commitment of manpower,

money, and expanded basic and applied research programs.

Two major considerations affect any management activities in the alpine, First, because

of the apparent high natural runoff efficiency,

the alpine may be most productive in yielding

water through passive management rather than

through the application of manipulative technologies. Second, a conservative approach to

the development of nonwater resources may

be the most prudent course until a better understanding of the hydrologic significance of this

environment is obtained. Future environmental problems may become more severe as the

result of other human activities on the alpine

zone—e.g., mining, grazing, and recreational

uses (table 37), Eventually, these kinds of activities may in turn affect the quality and quantity of runoff produced in that zone (13),

THE MONTANE ZONE

Introduction.—The montane zone generally extends downward from the timberline to

the foot of the mountain ranges. Its vegetation

is largely coniferous forest, but the types of

trees and their spacing vary in a complex fashion with latitude and altitude, The dominant

precipitation form is winter snow. The headwaters of eight of the nine major water re-
Ch. VI—Technologies Affecting Precipitation and Runoff ● 161

.-

Table 37.—Summary of the Nature and Extent

of Alpine Disturbances in the Western

United States as of 1976

Extent of disturbance

Percent

of total

Nature of disturbance Hectares Acres disturbed

Grazing . . . . . . . . . . . . . 256,194 633,056 74.5

Recreation. . . . . . . . 38,140 94,244 11,1

Mining ... . . . . ., . . . . . . 34,677 85,686 10.1

Roads. ... . . . . . . . . . . . . . 12,748 31,499 3.7

Pipelines . . . . . . ., 683 1,689 0.2

Power lines . . . . . . . . 289 714 0.1

Reservoirs . . . . . . . . . . 274 676 0.1

Other . . . . . . . . . . . . . . . . . 795 1,964 0.2

Total disturbance . . . . . . . . . 343,800 849,528 100.0

Total area of alpine ..,..,. 2,915,951 7,205,315 —

Percent disturbed .. . 11.8 11.8 —

Additional

anticipated by 1980. , . . . 57,646 142,444 16.7a —

aBased on the 1976 total

SOURCE R Johnston and R Brown, ‘Hydrologic Aspects Related to the

Management of Alpine Areas“ USDA reprint from Special Management Needs of Alpine Ecosystems Intermountain Forest and Range

Experiment Stat Ion Ogden, Utah, 1979

source regions of the Western United States lie

in this zone (see ch, III).

About 120 million acres of the Rocky Mountains lie within the montane zone. Snow waterequivalent accumulation depths in this area at

the end of the winter average about 2.5 ft annually, or approximately 320 million acre-ft of

water (6). In the Cascade/Sierra Ranges, the

other major mountain chain of the Western

United States, approximately 30 million acres

lie within the montane zone (2).

Experimental research dealing with the relationship between forests and surface streamflow has been conducted for at least 100 years

(17). The first recorded U.S. experimental study

of the effects of forest removal as a planned

land-use change on streamflow started in 1910

at Wagon Wheel Gap, Colo. By the 1960’s, work

accelerated on the potential for water production through timber-removal techniques in the

montane zone [2,14). Some 200 forested experimental watersheds were under study throughout the United States by 1960. In the Western

United States, at least six experimental watershed areas have been instrumented and studied

for water production. These experimental

watersheds located in Arizona, California, Col-

—-.—

orado, and Oregon, represent a variety of hydrologic environments (2).

Almost all experimental work on water-production technologies in these watersheds has

been conducted by the U.S. Forest Service, the

Federal agency responsible for management of

most montane areas in the Western United

States. Most work has involved timber removal,

either through clearcutting, patch-cutting, or

thinning. Clearcutting is a procedure that totally removes forest cover and may involve an entire watershed. This procedure is designed to

minimize transpiration losses, Patch-cutting involves opening the forest cover in a patch or

strip whose width is about three to eight times

the tree height and whose area totals 30 to 50

percent of the forest area. Patch-cutting is

designed to redistribute winter snowfall by

concentrating it within openings for maximum

capture and storage,

Assessment.—In certain situations, vegetation management through timber harvesting

may produce local increases in water yield. Application of this technology to increase surface

runoff has generally been restricted to experimental watersheds. Work remains to be done

on its general application and value on a larger

scale and to unstudied watersheds of the Western United States for purposes of supporting

arid/semiarid agriculture. Also needing more

attention are the extent and nature of the impacts of this technology on other major elements of the hydrologic cycle.

A number of attempts have been made by the

Forest Service to estimate and predict the sitespecific, water-related results of its timber removal experiments. Early evaluations of results

were based on classical hydrologic methods involving paired-basin comparisons and before/

after treatment studies (6). The comparisons

have since been augmented by basin simulation models.

Studies of the Fool Creek basin at Fraser,

Colo., have been the basis for Forest Service

predictions that streamflow water yields from

Rocky Mountain forests might be increased by

2 to 3 inches annually through selective patchcutting (fig. 34) (14), In this central Colorado
162 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 34.— Average Runoff Hydrographic for

Experimental Watershed

watershed, 40 percent of the old-growth lodgepole pine and spruce-fir forest were strip-cut

in 1955. Results from experimental forest modification in the west coast montane forests have

led to similar predictions (2).

Questions of whether these increases can be

maintained and whether they can be detected

at downstream arid/semiarid agricultural sites

are important, both in terms of the technology

potential and its economic feasibility for Western agriculture. The maintenance of runoff increases depends on several variables such as

the amount of snow stored in drifts, the amount

of sustained reduction in evaporation, natural

regeneration features of the harvested area, and

measures applied to control regrowth (2). For

example, new plant growth may reduce surface

water yield (2,20). If this hydrologic response

occurs, regrowth must be controlled to sustain

initial water-yield increases. Moreover, using

existing stream-gaging technology, it may be

difficult to detect increased yields at points

downstream where arid/semiarid agriculture

is practiced because such increases are relatively small when combined with the entire volume of watershed runoff at the point of use.

Application of runoff results obtained in

experimental watersheds to unstudied watersheds presents other questions in view of the

range of hydrologic responses possible from

site to site (box K). Within unstudied watershed

areas, various elements of the hydrologic cycle still are unmeasured. Inferences must be

drawn and assumptions made concerning the

manner in which these unmeasured variables

interact. Researchers often use statistical

trends of hydrologic relationships identified in

studied watersheds to predict hydrologic effects from timber removal in other watersheds.

These methods must be used with care because

the extension of results from experimental watersheds to other areas sometimes may not be

valid (17).

The meaning of experimental results regarding the relationship of timber removal and increased surface runoff remains unclear. Studies of the natural hydrologic activity of a subalpine forest in the Appalachian Mountains in

the Eastern United States found that 42 percent of the total annual precipitation to that

watershed was added by cloud-droplet condensation on the trees of the watershed. According

to this research, if this forest vegetation were

removed, total precipitation reaching the surface from that part of the watershed would be

reduced and runoff would decrease. Some Russian watershed-management studies have produced results indicating that in forests where

almost all annual precipitation occurs as snow,

and runoff is produced primarily by the spring

snowmelt, streamflow decreased as the forests

were removed (17). More recent studies reported by the Forest Service tend to support

the Russian results. Leaf (14) found that

“[w]hen 40 to 50 percent of the mature sprucefir timber volume is removed from north slopes

on a selection-cut basis, water yields may actually decrease somewhat. ”

More recently, Hawley and McCuen (12) analyzed the relationships that exist between water

yield and 17 environmental variables for 605

watersheds in the Western United States, They

found that the 11 westernmost States could be

best represented by five hydrologic regions (fig.

35). In each of these regions, precipitation was

the most important factor in determining water
Ch. V/— Technologies Affecting Precipitation and Runoff ● 163

Box K.—Managing Vegetation for Water Production: Perspectives From the U.S. Forest Service

A review of recent U.S. Forest Service literature that considered the possibility of using forestmanagement practices to increase water yields illustrates some of the complexities associated with

application of this technology. According to their research (Hibbert, 1983; Kattelman, et al., 1983;

Troendle, 1983; Harr, 1983; and Douglass, 1983), each of the major forest and range biomes of

the United States shows potential for water-yield augmentation from forest management. For example, in the Eastern United States, scientists report that “we know how to manage forests to improve water yield and the potential for increasing the water supply is enormous” (Douglass, 1983).

Similarly, in the mountainous regions of western Washington and Oregon, the potential for augmenting water yields appears high (Harr, 1983). Some potential also exists for increasing water yields

by managing rangeland vegetation on watersheds where average precipitation exceeds 18 inches

per year, in some regions of the Colorado Rockies, and in parts of California (Hibbert, 1983; Troendle, 1983; and Kettlemann, et al., 1983).

Notwithstanding these results, these same researchers caution that the expectation that vegetation manipulation can and will provide significant additions of water for Western agriculture may

not be realized. Kattleman and associates report that the large streamflow increases demonstrated

on small experimental watersheds in California’s Sierra Nevada diminish rapidly when spread

over a major river basin under multiple-use management. Furthermore, these researchers note that

the absence of large-scale studies limits their conclusions to little more than conjecture.

This is not an isolated problem. In the Rocky Mountains, Troendle reports that the role of

snowpack manipulation and evapotranspiration modification is not well defined. Moreover, Troendle adds that a watershed’s capacity to store water and yield “excess” water varies across the area,

and from a practical standpoint, only a small part of the watershed is now available for vegetation

management, Others have concurred with this opinion. On lowland rangelands, Hibbert estimates

that less than 1 percent of the Western rangelands can be managed to increase water yield and

that little or no increase can be realized by eradication of low-density brush and certain woodland

types. Scientists in the Pacific Northwest concluded that, realistically, watersheds will not be managed to produce more water (Harr, 1983).

SOURCES: James E. Douglass, “Potential for Water Yield Augmentation From Forest Managment in the Eastern United States,” 1983. R. Dennis Harr, “Potential

for Augmenting Water Yield Through Forest Practices in Western Washington and Western Oregon,” 1983. Alden R. Hibbert, “’Water Yield Improvement

Potential by Vegetation Management on Western Rangelands,” 1983. Richard C. Kattlemann, Neil H. Berg, and John Rector, “The Potential for Increasing Streamflow From Sierra Nevada Watersheds,” 1983. C. A. Troendle, “The Potential for Water Yield Augmentation From Forest Management in

the Rocky Mountain Region,” 1983. All of the above are in Water Resources Bulletin 19, in press.

yields, followed by elevation and air temperature. Land-use variables, including vegetation

cover density, did not correlate well with water

yield. For purposes of predicting water yield

from a Western watershed, vegetation cover

density “did not significantly improve the accuracy of the estimates where the precipitation,

elevation, and temperature variables were also

used in the estimation equation. ”

Such studies as these underscore the need

for additional research before timber removal

from the Western montane is a generally acceptable technology to increase water supplies

for downstream arid/semiarid agriculture. At

some sites it may be difficult to determine with

any certainty the short-term effects of timber

removal on the hydrologic activity of the various components affecting the arid/semiarid

agricultural area. It may become even more difficult to determine with some degree of accuracy the long-term hydrologic effects and potentials of different watersheds for Western

agriculture and development in general.

It has been suggested that the effects of timber harvest activities on soil erosion and increased sedimentation may far outweigh any

beneficial effects on streamflow (8), The

amount of soil erosion and sediment production that may result from timber removal will

be related to local variation in climate, terrain,
164 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 35.— Regions of Hydrologic Similarity

Regions of hydrologic similarity, based on the relationship

between annual runoff and precipitation, elevation, and

temperature variables in the Western United States. No two

regions respond i n the same way to these controls on runoff.

Regional

SOURCE M Hawley and R MuCuen ‘Water Yield Estimation in Western

United States,“ J. Irrig. and Drainage Division Proc. A. Soc Civ

Eng., 108 (No. IRI) 2534, 1981

vegetation, and the type and size of timber harvest undertaken (fig. 36). Forest Service literature indicates that most forests in the Western

United States have a natural sediment yield of

approximately 45 tons/mi2

/yr; logging operations have increased this annual yield to between zoo and 2,000 tons/mi2

, depending on

the particular logging technology employed (2).

Cumulative environmental impacts of any regrowth control measures must also be assessed.

If regrowth control involves repeated use of

mechanical or chemical measures, additional

environmental impacts may be created both

onsite and downstream through increased

chemical pollution and sedimentation.

Finally, the potential of timber-removal technologies in the montane for increasing surface

— .- —

runoff involves the question of scale. Opportunities for application of timber-removal technology for water production exist on a relatively small portion of the total forested acreage.

A realistic expectation of the amount of additional water that could be produced in the next

50 years under a timber-removal approach to

watershed management in the montane forests

would be approximately 3.7 million acre-ft (2).

A large but unspecified amount of this water

would be produced by Western forests. This

figure represents less than 1 percent of the

present mean annual runoff from the 17 Western States and, as has been noted previously,

would be difficult to detect by existing streamgaging networks at distances from the modified

watershed where arid/semiarid agriculture is

practiced, Some question exists also regarding

the desirability of extensive modification of

Western surface area, especially when wilderness and other less modified, natural mountain

environments are involved. A watershed-management technology that might substantially

alter a minimum of 10 percent of the Western

forests and may not produce a significant addition to the water needs of arid/semiarid agriculture may be difficult to justify from the point

of view of agriculture.

Lowland Watersheds

INTRODUCTION

Many lowland watersheds are used for livestock grazing and the technologies affecting

surface runoff are often associated with range

management. The technologies applied to lowland watersheds that are considered in this section are designed to produce additional surface

runoff for offsite use. Broadly, the technologies

consist of: 1) vegetation removal and replacement (brush control), and 2) runoff agriculture.

Both types of technologies are used to increase

water yields by facilitating a shift of water from

one component of the hydrologic cycle to another.

VEGETATION REMOVAL AND

REPLACEMENT (BRUSH CONTROL)

Introduction.—Much of the vegetation in

lowland areas consists of grasses, forbs, and

shrubs. Technologies that manipulate vegeta-
Ch. VI— Technologies Affecting Precipitation and Runoff ● 165

— -—

Figure 36. —The Effect of Watershed Condition on Rainstorm Runoff and Erosion

2.44 inches of rain In 1 hour

Good

ground cover—

60-75°/0 of ground

covered with plants

and litter

Fair

ground cover—

37°/0 of ground

covered with plants

and litter

Surface

tion on these sites can have two purposes:

1) to increase offsite water yield by replacing

deep-rooted shrubs with shallow-rooted grasses

or forbs that consume less water (also see discussion of phreatophyte management in ch.

VII), or 2) to increase soil water available to

forage plants by controlling less palatable

shrubs (see chs. IX and XI).

Vegetation removal can be accomplished in

several ways, and each method has different

effects on vegetation and soils. For example,

mechanical brush control is used widely in

some areas. Some types of mechanical brush

control [e. g., hand slashing, shredding, roller

chopping) remove only the top growth of the

plant and result in minimal soil disturbance;

others (chaining, cabling, disk plowing, grubbing, railing, bulldozing, and root plowing) remove the entire plant and can result in extensive soil disturbance. Generally, high labor and

energy costs are associated with these practices, and rough terrain can limit their application.

Herbicide application can also be used to

control vegetation on some shrub-dominated

rangelands. Generally, herbicides have an

advantage over some other brush control methods because of their relatively low costs, selectivit y in control, reduced labor requirements,

safety and utility in rugged terrain, maintenance of ground cover, and minimal soil disturbance (5].

A third method of brush control is by fire,

the oldest known practice to manipulate vegetation. Prescribed burning is an inexpensive

and often effective type of control that can be

used in combination with other brush control

methods for long-term brush control. However,

in some cases, brush areas cannot support a

fire, and because the burned land is denuded

for a short period of time, the potential for erosion may be high, especially on steep land or

where the soil is not firm,

Finally, vegetation can be manipulated

through biological conversion or elimination,
166 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

These methods employ grazing animals, insects, or pathogens to control plants. The control agent can either change plant composition

directly or indirectly by reducing the vigor or

reproductive ability of the target plant or by

promoting disease.

Assessment.—The effects of brush control

on the hydrologic characteristics of a watershed are a result of the interactions among the

vegetation, the type of control used to manipulate vegetation, site characteristics (e. g., soil

and slope), climatic factors (e.g., rainfall

amounts and distribution and storm intensities), weather before and after application, and

posttreatment practices (5). Because of the normal variability of these factors, the effects of

brush control will vary naturally over time and

from area to area,

To date, the evaluation of brush control on

the hydrologic characteristics of watersheds

has received little research attention (5). Instead, most studies have focused on livestock

response or vegetation change as a result of

vegetation manipulation.

Some research suggests, however, that brush

control may increase offsite water yields under

certain site conditions. For example, in heavy

brush-infested chaparral or mesquite watersheds that receive at least 20 inches (508 mm)

of precipitation each year, vegetation manipulation may increase water yields from these

sites, but brush control must be maintained (5),

Limited offsite water-yield increases can also

be expected by converting brush to grass and

forbs at the higher precipitation zones of pinyon-juniper or mountain big sagebrush watersheds. On other rangeland watersheds, however, when shrubs are replaced by grasses and

forbs, the herbaceous vegetation uses the available soil moisture equally well, and little or no

offsite water-yield increases can be expected.

Brush control to increase offsite water yields

has been restricted to relatively small experimental sites. Many questions remain about the

application of this technology on a larger scale

and under different conditions (e.g., vegetation

types, soil types, topography, and brush control practices). Environmental effects of these

-.

practices also require resolution. In some

cases, large-scale vegetation removal could result in accelerated soil erosion and sediment

production, degraded water quality, increased

flood hazard, and diminished fish and wildlife

habitat, Application and maintenance costs

must be determined and compared to the benefits derived from their use.

The following plant communities are considered to be especially troublesome to range managers, though they are not the only plants considered problems. Rather, these examples represent some of the range plant communities

where hydrologic data are available:

Sagebrush-Dominated Rangelands.—Sagebrush-dominated rangelands are most abundant in the intermountain region, and some

range managers estimate that these areas produce forage at about one-half of their potential (5). Sagebrush (Artemisia) is a natural component in many plant communities but readily replaces the grasses under heavy grazing

pressures, Since the 1940’s, a major effort has

been made to clear sagebrush-dominated lands

and reseed these areas to introduced grasses,

such as crested wheatgrass (Agropyron cristatum).

Most research on sagebrush-dominated

rangeland has evaluated livestock response or

vegetation change as a function of brush control (5). In studies of the influence of sagebrush

control on hydrologic variables, research indicates that infiltration rates, sediment production, runoff, and erosion will vary with location and type of brush control. For example,

herbicide application usually has the least effect on hydrologic characteristics (5). Mechanical methods of brush control have a limited

effect on offsite water yields and sediment production, depending on the degree of soil disturbance, the success of reseeding operations,

and other site characteristics (5). The effect of

prescribed burning on hydrologic characteristics has not been studied on sagebrush dominated rangelands. In general, research shows

that sagebrush or grass vegetation use most of

the available soil water, and brush control will

not increase offsite water yields, although a
Ch. VI— Technologies Affecting Precipitation and Runoff . 167

large increase in forage production can be expected.

Pinyon-Juniper Dominated Rangelands.—

Pinyon (Pinus)-juniper (Juniperus) woodlands

cover extensive areas of some watersheds in

Arizona, Colorado, New Mexico, Nevada, Texas, and Utah. They occur mostly at intermediate elevations in areas receiving less than 20

inches (500 mm) of precipitation each year and

usual l}’ have limited commercial value. These

trees intercept precipitation, which is then

evaporated without reaching the ground, or

consume water through transpiration that

might otherwise be available for forage plants.

Pinyon-juniper woodlands typically have low

livestock-carrying capacities, a result, in part,

of tree-stand density and of the invasion of

trees into grassland.

Mechanical methods of brush control, such

as slashing, bulldozing, and chaining, are the

primary methods used to control this vegetation, although fire and herbicide application

have also been employed. Studies that have

evaluated the influence of pinyon-juniper control on watershed variables have focused mostly on offsite water-yield increases after application, Results of these treatments have varied.

For example, one study of the Beaver Creek watershed in Arizona applied three different

Photo credit: USDA-Soil Conservation Service

Junipers being cleared with an anchor chain pulled by

two tractors as a demonstration to develop methods

to reduce clearing costs on good range sites

brush-control techniques (cabling, herbicide

application, and hand slashing) to paired watersheds in an effort to boost water yields (5),

Herbicide application significantly increased

runoff, but hand slashing and chaining had little effect on runoff, possibly the result of surface modifications that trapped runoff. Based

on limited sediment data, no significant change

was observed in sediment yield after cabling

operations or herbicide applications. Other

measures of water quality (e. g., total dissolved

solids, calcium, magnesium, sodium, potassium, and chloride) were lowest in herbicidetreated watersheds and highest from the cabled

watershed (5),

In another study, Wright and associates (5)

studied prescribed burning of bulldozed ashe

juniper (Juniperus ashei) on six paired microwatersheds (0.02 to 0.19 ha) in west-central

Texas and found significantly increased runoff

and soil erosion on moderate and steep slopes.

Controlling pinyon-juniper on gentle slopes (1

to 4 percent) had minor effects on water yields

and soil erosion. Sediment loss continued on

the moderate and steep slopes until vegetation

and mulch cover reached about 70 percent, a

period of about 9 to 15 months on moderately

steep watershed and 15 to 18 months for the

steep watershed.

Chaparral-Dominated Rangelands.—Chaparral refers to dense stands of shrubby plants

dominated by broadleaf and narrowleaf, nondeciduous species, many of which vigorously

sprout following removal of the aboveground

parts. Chaparral is common to the Southwest

and California and is characterized by shrubs

such as live oaks (Quercus), mountain mahogany (Cercocarpus), manzanita (Arctoscaphy10S), and

research

cerned wi

convertin

perennial

erosion.

eanothus (Ceanothus). Watershed

n chaparral areas has been conh offsite water-yield increases from

chaparral-dominated watersheds to

grasses or the effect of fire on

Mechanical, herbicide application, and prescribed burning have been used to control

chaparral. However, many chaparral species

are well adapted to fire, and this method alone
168 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

is not an effective control, Mechanical control

methods are often limited by terrain and are

most suited to nearly level areas.

Brush control on chaparral areas that receive

less than 20 inches (500 mm) of precipitation

annually will result in minor or no water-yield

increases (5), Where precipitation is greater, the

potential for increased yields appears to be

good; however, large variations in treatment

response are not well understood.

Use of fire as a brush-control method in chaparral areas reduces soil protective cover, produces a water-repellent layer in the soil, and

causes increased surface runoff and soil movement with relatively small storms (5). The results can increase the danger of floods, increase

erosion and sediment yields, and facilitate soil

slippage and landslides (5). Elevated levels of

nutrients in streamflow following fire may also

be associated with the high levels of erosion,

Mesquite-Dominated Rangelands.—Mesquite

(Prosopis) is an aggressive competitor and

often forms dense tangles of brush that reduce

range forage production and accessibility to

grazing animals, Many species and varieties

of mesquite are recognized—e.g., honey mesquite and running mesquite,

Research on the hydrologic effects of brush

control on mesquite is very limited. Where

studies have been conducted, control of honey

mesquite by several methods increased infiltration and either had no effect or decreased sediment production (5), When running mesquite

was treated with a herbicide and then burned,

infiltration rates were not significantly increased (5). Sediment production on areas subjected to the herbicide/burning treatment also

tended to be reduced compared to untreated

plots, possibly a result of improved grass cover

on the burned site.

RUNOFF AGRICULTURE

Introduction.—Because precipitation is infrequent in arid lands, farmers in lowland regions of the world have developed a variety of

techniques to collect surface runoff for use in

agricultural production. The theory behind

these practices is that water can be collected

from a large area and concentrated on a smaller, cultivated field for ample yields.

Historically, runoff agricultural systems allowed crop production in areas with as little

as 4 inches of annual precipitation, When modern irrigation technology became available,

many runoff agricultural systems were quickly replaced or abandoned and forgotten, Higher pumping costs for ground water, applicability to small-scale farming, availability of new

building materials, and recent research on runoff agriculture have rekindled interest in the

use of older technologies.

Runoff agriculture depends on water collection or “harvesting.” Water-harvesting systems

include two basic components: a catchment

area for collecting rainwater and a water storage facility, There are many kinds of each (fig,

37). Selection of a particular method is determined by soil, topography, amount and pattern

of precipitation, and climate,

Generally, water is collected on a soil surface

that has been treated to make it impermeable,

Treatments can include coats of paraffin wax,

asphalt/fiberglass membranes, layers of sodium

salts, gravel-covered plastic sheets, galvanized

corrugated sheet metal, concrete slabs, or

dense vegetative cover. Table 38 lists the features of some common catchment treatments,

Figure 37.— Catchment Surface With Butyl-Coated

Nylon Water Storage Bag

nylon bag

SOURCE J L Thames and J N Fischer, “Management of Water Resources in

Arid Lands, ” in Arid-land Ecosystems. Structure, Functioning and Man.

agement vol 2, D W Goodall and R A Perry (ed.) Cambridge, Mass

Cambridge University Press 1981), pp 519.547
Ch. V/— Technologies Affecting Precipitation and Runoff 169

Table 38.— Potential Catchment Treatments

Runoff Estimated Initia l

efficiency life cost

Treatment (percent) (years) ($/m2

)

Land smoothing

—

and clearing . 20-35 5-1o 0.01-0.06

Water repellents ... . . . 60-85 5-8 0.15-0,20

Paraffin wax . . . . . . 60-95 5-8 0,30-0,50

Gravel-covered sheeting 75-95 10-20 0.40-0.60

Asphalt-fabric membranes 85-95 10-20 1.25-1.75

Concrete, sheet metal,

artificial rubber . 60-95———.

10-20 3.00-5.00

SOURCE G W Frasier Water for Animals, Man and Agriculture by Water

Harvesting G R Dutt C F Hutchinson and M A Garduno (eds)

Rainfall Collection for Agriculture in Arid and Semiarid Regions

(Sough. U K Commonwealth Agricultural Bureaux 1981) PP 83-86

Structures designed for other purposes, such

as house roofs and roads, may collect water inadvertently, and this water can be used for agricultural purposes as well.

Collected water is stored in tanks or reservoirs. For many water-harvesting systems, the

storage facilities are the more expensive item,

but they are often vital to the success of a harvesting system, Typical storage facilities include butyl bags, steel tanks, and waterproof,

excavated pits. It is possible that natural

depressions such as playa lakes (“wet weather

lakes”) or preexisting storage facilities could

be used also. Stored water is diverted to irrigate

fields; directed into small basins around individual trees (microcatchments); or held temporarily behind a series of terraces.

An alternative practice to the use of catchment and storage facilities is “floodwater farming, ” whereby sporadic flashfloods that occur

in watercourses of arid lands are managed to

Photo credit: USDA Soil Conservation Service

Masonry and water spreaders. Stock grazing on spreading area treated with rock percolators on contour
170 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

supply water for crops. For example, crops can

be planted in the bottom of intermittent watercourses, and dams can be used to control water

when flashfloods occur; or crops can be

planted at the point where intermittent watercourses spread into an alluvial fan.

Assessment.—A variety of crops can be

grown using water obtained from surface runoff. Generally, crops need to be deep-rooted,

drought-resistant, and suited to local soils,

climate, and precipitation, The Papago Indians,

for example, grow a number of vegetables

using this practice, and some crops have been

bred especially for this purpose. Other possible crops are jojoba, Christmas trees, tree fruits,

grains, and wine grapes, Runoff agriculture

can also be used to aid in establishment of

plants that will not be harvested. For example,

water-harvesting technology is being used in

Mexico to aid in reseeding degraded rangelands.

Runoff agriculture systems that use waterstorage facilities have been used extensively for

animal watering to provide dependable sources

of water for livestock and wildlife when other

supplies fail. Some small systems that furnish

water for wildlife in remote areas have been

developed on public lands. Larger systems with

both large catchment areas and storage facilities can provide water for several hundred

head of livestock.

With current technologies, runoff agriculture

has some physical, biological, and economic

limitations, The systems depend on rainfall and

are no more dependable than the weather. In

areas with less than 2 to 3 inches (50 to 75 mm)

of annual rainfall, costs of application and

operation for water catchment and storage

facilities may outweigh benefits of increased

crop production, In addition, the high costs of

these technologies restrict its use to small-scale

applications such as livestock or wildlife.

Runoff agriculture systems also vary widely

in their efficiency in collecting precipitation

because of differences in soil, topography, climate, pattern of precipitation, and the materials used for catchment and storage facilities.

Limited experience has shown that some catchment and storage facilities can collect 20 to 40

percent of precipitation, More elaborate systems can collect more than 90 percent,

Lifespan of the soil treatments is limited also,

and replacement is costly, While these have improved greatly in recent years, the least expensive treatments still must be replaced every 5

to 10 years (table 38), Maintenance is often required because poorly designed and maintained facilities can cause soil erosion or local

flooding. The site-specific nature of these facilities also contributes to their high cost. Each

facility must be designed for its location and

intended use.

Some scientists believe that with the rise in

energy costs, runoff agriculture may compete

more favorably with conventional sources of

water. Questions remain, however; information is needed on the application of large-scale

runoff systems on conventional agricultural

crops and on the more complex effects of these

systems on crops. For example, with jojoba it

is known that runoff farming cannot be recommended when there is danger of severe, early

frosts, since ample supplies of harvested water

in the fall encourage growth that is very susceptible to spring freezing.

Questions have been raised also over the

long-term effects of soil treatments on soil and

water resources. Information on the quality of

water from areas where the soil is treated is

limited; some possibility exists that water from

catchments could be contaminated by materials used for waterproofing.

SreamfIow Forecasting

Introduction

Effective reservoir management requires

some advance knowledge of both the timing

and volume of runoff into the reservoir so that

releases from the reservoir can be scheduled

to meet identified demands and priorities most

effectively, Runoff forecast technologies have

been developed to facilitate acquisition of this

knowledge.

There are two broad categories of streamflow-forecast technologies. First, some technol-
Ch. VI—Technologies Affecting Precipitation and Runoff 171

ogies forecast runoff resulting from rainfall by

combining meteorological forecasting, soilmoisture accounting, and flow routing. Second, some technologies forecast spring snowmelt runoff from mountain watersheds. These

involve an evaluation of the amount of snow

present each spring at the beginning of the melt

season, how the snow melts, and the way it

enters the river system.

Technologies that forecast spring runoff are

particularly important in light of the major role

of this water source in meeting Western water

demands. A variety of approaches to forecasting runoff from melting mountain snowpacks

has been developed by Federal and State agencies responsible for various aspects of water

resource development or management in the

West, However, comparative analyses of these

approaches are rare. Much of the following is

adapted from Lettenmaier, et al. [15].

In the arid interior of the West, developers

of the earliest water projects saw the potential

for using winter snow depth measurements in

the mountains as an indirect indicator, or “index,” of runoff to be expected during the spring

and summer snowmelt period. By the 1930’s,

a network of snow-measurement stations was

established, With the expansion of the data

base over time, forecasting methods have used

an increasing number of indirect index indicators for predicting runoff—e.g., snow-course

readings (the average of 10 individual measurements of a single site), winter precipitation at

low-elevation stations, soil-moisture measurements, and areaI extent of snow cover. In each

case, attempts were made to relate statistically some easily measured variable, such as the

water content of the snowpack at a point, to

the complex of interactions that determined the

volume and timing of spring snowmelt runoff.

With the advent of the digital computer, the

level of detail that could be considered by numerical models of snowmelt and runoff physical processes was vastly increased. This

prompted the development of simulation models of runoff and later of snow accumulation

and melt processes. These models attempt to

trace the fate of incident precipitation to its

ultimate fate as stream flow, evaporation, or

ground water recharge. Similarly, snowmelt

Photo credit USDA-Soil Conservation Service

Snow surveyors weighing snow sample at Upper

Wheeler snow course in Washington State

(snow accumulation and melt) models attempt

to simulate the history of water storage in a

snowpack, including the melt process. Together, these models produce a simulated record of effective precipitation consisting of rain

on bare ground and snowmelt, The record is

used as input to a soil-moisture accounting

model.

Simulation models are generally data-intensive and require an experienced user for successful implementation. They have been used

for a variety of purposes, of which flood forecasting is one of the most important, However,

they have also been used for seasonal runoff

forecasting, notably by the California Joint

State-Federal River Forecast Center and the

National Weather Service (NWS) Hydrologic

Research Laboratory.

The advantage for using conceptual models*

is that they allow explicit consideration of such

factors as soil moisture, which is not usually

included in index models. They also allow convenient exploration of alternative scenarios.

The Sacramento River Forecast Center, for ex-

* F’or a [iis( ussion of water models in general, see the OTA

assessment: [ ~.se of” Alo(]el,s fi)r tl’a(er Resources Afanab~en]t?nt,

Planning, an[f I)ol](;j, OTA-()-1 59, August 1982.
172 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands — .

ample, was able to provide streamflow forecasts during the 1976-77 drought that were considerably more accurate than those achieved

using index methods,

Institutional Responsibilities

Streamflow forecasting has been undertaken

seriously for approximately the past 30 years.

Responsibilities for runoff forecasting are

dispersed among several Federal agencies, and,

to some extent, each has developed its own approach to the preparation of a streamflow forecast. Only the NWS of NOAA and USDA’s Soil

Conservation Service (SCS) are mandated to

disseminate forecasts publicly.

In the early 1930’s, Congress provided funds

and directed the Secretary of Agriculture to initiate a program of snow measurement to be

used to estimate the amount of water expected

to be available for irrigation use in the coming crop season. This cooperative snow survey

and water supply forecast program was first

assigned to the Bureau of Agricultural Engineering and later transferred to SCS, where it

has remained since approximately 1950 (24).

Beginning in the late 1940’s, the U.S. Army

Corps of Engineers and NWS jointly undertook

another program entitled the “Cooperative

Snow Investigations Program, ” Its purpose

was to initiate an interagency effort to develop

the necessary tools for analyzing snowmelt

runoff in connection with the respective authorities of the Corps of Engineers and NWS.

It included contributions by other agencies,

such as the Bureau of Reclamation and the U.S.

Geological Survey (USGS) (18), This effort

ultimately contributed to the development of

the Streamflow Synthesis and Reservoir Regulation (SSARR) model, which is used by the

Corps of Engineers and NWS in their joint reservoir-management activities in the Western

United States, primarily in the Columbia River

basin.

Working independently, in the 1940’s NWS

(then the Weather Bureau) began to develop

short-term forecasting techniques and water

supply forecast procedures (1). The Office of

Hydrology of NWS began experimenting with

continuous streamflow simulation models in

1964, leading to the creation of the NWS River

Forecast System (NWSRFS).

Beginning in 1967, SCS initiated the use of

.

a “parametric, deterministic, continuous wa-

tershed or basin simulation computer model”

primarily to monitor average annual runoff and

monthly runoff in several Western States. This

model also included an estimation of water requirements of irrigated agriculture,

The National Aeronautics and Space Administration (NASA) in the mid-1970’s began a research program designed around the ability of

satellites to obtain imagery of various mountain snowpack properties. The primary focus

is the area of the ground surface that is snow

covered at different times of the accumulation

and melt seasons. To date, research has relied

heavily on the interpretation of the satellite imagery that relates snow-covered areas in the alpine belt to snowmelt-streamflow from an entire mountain range. Unfortunately, little of the

satellite imagery data are readily available to

the scientific community at large; thus, no

broader use or independent verification is

possible. In addition, given the cost of satellite

imagery and the data processing required, the

costs of this approach currently outweigh its

benefits.

Also in the mid-1970’s, USGS developed the

Hydrometeorological Streamflow Prediction

(HM) Method as another forecasting approach.

In contrast to the more sophisticated attempts

of NASA, this approach uses available lowaltitude precipitation and runoff data from existing sites, Its primary advantage is the ease

with-which the data are obtained:”

of forecasting involves a simple

method based on precipitation

runoff,

the process

accounting

inputs and

Assessment

Water-supply forecasting for either internal

use or public dissemination is an activity in

which at least eight Federal agencies and one

State agency (California) are now engaged in

the Western United States. This has resulted

in some competition and confusion, For exam-
Ch. VI— Technologies Affecting Precipitation and Runoff . 173

pie, until the 1977 forecast season, both SCS

and NWS prepared duplicate forecasts for 260

points in the West. In some cases, the forecasts

proved to be significantly different, which resulted in some confusion among user groups.

In 1978 those agencies entered a cooperative

agreement to coordinate their activities and

jointly produce and publish “Water Supply

Outlooks for the Western United States. ”

A primary problem with the conceptual simulation models is the large amount of data required to use them and the relatively long computer running times involved (15). The USGS

HM model achieves a balance between data requirements and the desirability of including

some representation of physical processes in

seasonal forecasts. This model represents forecast season runoff as the difference between

total seasonal precipitation falling on the watershed and the sum of winter season runoff and

other losses from the system. The seasonal

precipitation is determined from measurements at low-elevation precipitation gages in

the original HM model. This model has been

modified to incorporate snow-course data (15).

The relationship between inputs and losses

from the system can be expressed also in terms

of basin storage, in which forecast season runoff is taken to be winter storage less losses plus

forecast precipitation,

The primary advantage of the HM model is

that it reflects soil water/runoff interactions in

a simple way, which is especially important in

— — .

extremely dry years, since an accurate forecast

is most valuable under extreme conditions, particularly droughts. It has been found that the

most accurate runoff forecasts were achieved

in extreme high and low runoff years. These

are conditions under which the earlier methods

perform most poorly, since the relationships

used were often linear and most inaccurate

when conditions were highly abnormal.

Improvement of runoff forecast accuracy is

of practical importance only if it has, some impact on water planning and use. The support

of water users for water forecasting programs

may be seen as some indication of the worth

of the forecasts, For instance, SCS, in considering possible changes to its snow survey and

water survey forecasting program, conducted

a survey during 1979-80 of users of the program. options included eliminating, continuing, or expanding the program, A large majority of the users supported continuation and/or

expansion (15).

Various attempts have been made to evaluate

forecast worth. * The most recent of these is the

work of Castruccio , et al, (7), which provides

estimates of the worth of forecast accuracy improvements throughout 11 of the Western

States where snowmelt runoff is the primary

source of surface runoff (tables 39 and 40). Five

—

*Currently, there is no direct cost to the users for SCS

forecasts, so it is not possible to employ a willingness-to-pay

criterion to assess the worth of the information.

Table 39.—Summary of the Regional Irrigation Data and Benefits

in the 11 Western Statesa

Percent total Estimated average

Benefit/acre impacted annual crop value/

USGS hydrologic region Benefit ($M) (in $/acre) irrigated acreage acre ($/acre)

Missouri . . . . . . . . . . . . . . . . $7.1 $1,14 30.9 $195

Arkansas Red-White . . . . . . 0.9 1,69 2.6 307

Rio-Grande . . . . . . . . . . . . 1.4 3.61 2.0 408

Upper Colorado . . . . . . . . 1.1 0.86 6.2 184

Lower Colorado . . . . . . . . . . 0.8 8.53 0.4 642

Great Basin . . . . . . . . . . . . . 2.8 1.56 8.7 209

Pacific Northwest . . . . . . . . 7.0 1.17 29.5 293

California . . . . . . . . . . . . . . . 5.5 1.39 19.7 592

aThe 11Western States are Arizona, California, Idaho, Colorado Oregon, Washington, Montana, Wyoming, New Mexico, Utah,

and Nevada

SOURCE : P Castruccio, H Loats D Lloyd, and P Newman, Applications Systems Verification and Transfer Projecf, Volume

VII: Cost Benenefit Analysis for the ASVT on Operational Applications of Satellite Snow-Cover Observations, National

Aeronautics and Space Administration Technical Paper 1828, 1981
174 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—. —

Table 40.—Summary of Computed Hydroelectric Energy and Other Relevant Data by USGS Hydrologic Region

Current a difference

1978 between Current a difference

percent of total hydroelectric & between 10 & 2°

hydroelectric steamelectric revenues from the Streamflow

USGS Benefit Benefit/MWh energy energy production sale of energy forecast

hydrologic region (vlF) $M ($/MWh) production (percent) (mills/kWh) (mills/kWh) error (percent)

Missouri . . . . . . . . . . . . 1.0 0.17 3.2 7.70 21.43 27.5

Arkansas Red-White . 0.05 0.18 0.1 7.73 21.41 29.0

Rio Grande . . . . . . . . . 0.1 1.03 0.1 17.57 19.16 43.8

Upper Colorado . . . . . 1.1 0.2 3.2 6.50 23.89 24,2

Lower Colorado . . . . . 2,1 0.46 2.5 18.07 15.33 89.9

Great Basin . . . . . . . . 0.1 0.24 0.3 19,36 4.36 39.4

Pacific Northwest . . 3.8 0.03 73,1 7.57 3.63 11.9

California . . . . . . . . . . 1.9 0.06 17.7 26.08 6.69 10.0

aValues shown have been adjusted for inflationary rises on production expenses (Inflationary factor = 1.21) and sales revenues (inflationary factor = 1.26)

SOURCE P Castruccio, H Loats, and D Lloyd, and P Newman, Applications Systems Verification and Transfer Project, Volume VII: Cost/Benefit Analysis for the ASVT

on Operarational Applicatlons of Satellite Snow-Cover Observations, National Aeronautics and Space Administration Technical Paper 1828, 1981

water uses that might be affected by water-supply forecasts have been identified: hydroelectric energy generation, irrigated agriculture,

municipal and industrial uses, navigation and

recreation, and fish and wildlife (7). Of these,

hydroelectric energy generation and irrigated

agriculture were identified as being by far the

most economically significant. In considering

an arbitrarily selected forecast improvement

of 6 percent over the existing situation, these

authors found a wide range of economic benefits for the individual water subregions of the

Western United States. The economic benefit

was found to be related to both the accuracy

of present forecasts and the value of agricultural products or electrical energy produced

by the water. For irrigated agriculture, they

projected increased economic values ranging

from $0,32 to $12,33 per surface water-irrigated

acre. The highest values were found for the

Lower Colorado River Basin, where forecast

accuracy is low and the value of crops produced by irrigated agriculture is high. The

lowest values came from the Pacific Northwest, where forecast accuracy is relatively

good. The economic benefit for hydroelectric

energy generation was calculated to range from

$0.03 to $1.03 per million watt-hour (MWh).

They calculated that the annual economic benefit for the 11 Western States resulting from a

6-percent increase in forecast accuracy for

irrigated agriculture would be $26,476,739

and for hydroelectric energy generation,

$10,032,798. These benefits are summarized in

tables 39 and 40.

Improvement of streamflow forecast accuracy, in general, is dependent on a number of factors, including forecast technology, watershed

characteristics, climatic conditions, and data

availability and reliability, In some cases,

where adequate data are available and existing

forecast methods are based on the development

of a simple statistical relationship between

some variable, such as snow water-equivalent

depth, and annual runoff volumes, it may be

possible to achieve forecast improvements of

at least 25 percent over existing methods (15).

More commonly, improvements in the range

of 10 percent appear to be a more reasonable

estimate. As noted above, even this modest improvement has the potential for producing a

considerable economic benefit by improving

the management efficiency of the reservoir

system of the Western United States.

Water-supply forecasting would benefit from

an increased understanding of the highland

watershed environment, It would also benefit

from increased coordination and cooperation

among the various Federal and State agencies

involved, primarily to eliminate any areas of

duplication. Primary research efforts could be

directed toward improving the ability to forecast the timing of the annual spring runoff.

Forecasts of annual volume are reasonably accurate for most of the forecast techniques, al-
Ch. VI—Technologies Affecting Precipitation and Runoff * 175

— -. — . .

though some effort could be expended in ob- forecasts of streamflow volume for certain retaining small increases in this accuracy. It has gions in the Western United States would have

been suggested that even small increases in the considerable economic benefit for agriculture,

Three major categories of technologies

(weather modification, watershed management, and streamflow forecasting) have

evolved to estimate and manipulate the surface

runoff produced annually or seasonally by precipitation on watersheds in the Western United

States. Debate and uncertainty exist in each of

these categories regarding their effectiveness

and potential.

The two weather-modification technologies

that have received the most attention are those

involving: 1) winter storms that cross the major mountain ranges of the Western United

States, producing the snowpack of the mountain watersheds, and 2) the summer cumulus

clouds that produce rain and hail, often in large

amounts over limited areas. While “seeding”

these air masses could produce additional precipitation under the right conditions, more

research is needed on whether this reaction results in increased soil water or surface runoff

in the target area, Additional information is

also needed on the physical interaction between the artificial nucleating agent and the

existing physical properties of an air mass and

on the development of acceptable verification

criteria for evaluating the success of a cloudseeding experiment.

Watershed-management technologies are designed to manipulate the water resource once

precipitation has reached the ground for onsite or offsite use, In the Western United States,

the most important of these technologies from

the standpoint of volumes of water are those

intended to increase surface runoff from the

highland mountain snowpack.

The most water productive of all the major

biophysical environments of the region is the

alpine zone, that zone in the highest elevations

of the major mountain ranges, This zone has

received little scientific attention, The few

alpine studies suggest that a

passive-management approach

most beneficial technology for

conservative,

may be the

the present.

Technologies that affect the montane zone

have involved, to a great extent, the removal

of all or portions of the mountain forest in an

attempt to alter snow-accumulation patterns,

evapotranspiration losses, or rates of meltwater

production. It has not yet been established that

forest removal will result in predictable runoff

increases for downstream arid/semiarid agriculture.

Attempts to modify the surface runoff regime

in lowland watersheds involve a wide range of

technologies, depending on the specific environment involved and possible objectives. In

some cases, the production of increased runoff

is desired; in others, the retention of water for

onsite uses is the goal. Generally, the approach

is to modify vegetation or the physical surface

area of the site. Results in these regions have

been variable because of the different objectives and because of natural variations in lowland watersheds.

Water-supply forecasts are undertaken by

several Federal and some State agencies to improve regulation of reservoirs that control the

surface flow of Western rivers. These efforts

sometimes are not coordinated and include aspects of duplication and inconsistency. A wide

range of forecast models exists, from very sophisticated, computed simulation technology

to simpler statistical correlation models, Research has indicated that no single forecast

model is sufficient for all hydrometeorological

environments in the West. In general, those

models having the simplest data and computer

processing requirements would appear to be

most desirable, strictly from local use, economic, and efficiency standpoints, An example of

this type of model is USGS’s HM model. At-
176 . Water. Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

tempts are being made also to incorporate satellite imagery and data acquisition by remote

telemetry into the data input required for forecasting. Much improvement is possible in forecasting techniques to assist in more effective

water-resources planning and management for

all Western users, including the major user,

agriculture.

Each technology assessed in this chapter has

demonstrated that it can, at least on a local,

site-specific basis, either augment runoff from

mountain watersheds or forecast the volume

of that runoff. In every case, however, it has

proven difficult to demonstrate that the results

can be generalized over extensive areas. Of the

technologies to augment runoff, precipitation

augmentation from winter orographic storm

systems by “cloud seeding” appears to show

the most potential, This technology, while not

living up to some of the claims of its more enthusiastic supporters, has been developed within a solid scientific framework that has created

a body of knowledge that should facilitate future studies. Watershed management, on the

other hand, has been approached largely as an

adjunct of commercial logging operations. For

this reason, the relationship between deforestation or afforestation and water yield from

highland watersheds is much more speculative.

This entire subject area would benefit from a

more rigorous scientific approach emphasizing water yields rather than timber production

if it is to be given serious consideration as a

technology capable of producing additional

water for Western agriculture. Technologies

for the management of lowland watersheds to

increase water yield can be applied locally (e.g.,

to produce water for stock ponds), but in general they cannot create sufficient additional

runoff to affect regional supplies, except in exceptional circumstances.

Water-supply forecasting is gradually developing approaches based on more realistic models and more sophisticated data collection techniques. Water-supply forecasting technologies

should form the foundation of water management and planning in the Western United

States. As such, responsible Federal agencies

should be encouraged to evaluate critically the

existing forecast systems, to develop a more

detailed study of the processes controlling

snow accumulation, melt, and runoff from

highland watersheds; and to coordinate their

efforts with those involved in precipitation

augmentation and watershed-management

technologies,

Finally, a more coordinated approach to the

study and management of highland hydrologic

systems would greatly benefit each of the technologies discussed in this chapter. Ideally, the

goal of this effort would be the development

of an ability to trace the path and history of

water from the time it originates as augmented

precipitation in a winter orographic storm

through deposition, melt and ultimate runoff

into either the rivers or reservoirs of the region,

and evapotranspiration or percolation to

ground water.

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Ch. VI— Technologies Affecting Precipitation and Runoff . 177

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RM-142, Rock~ Mountain Forest and Range Experiment Station, Fort Collins, Coio., 1975.

Lettenrnaier, D., Erikson, K., and Parkinson, D.,

“Evaluation of Snowmelt Forecasting Methods, ” Technical Report No. 68, Charles W. Hariss Hydraulics Laboratory, Department of Ci~~il

Engineering, University of Washington, Seattle, 1980.

Martinelli, M., Watershed Yield Improvement

From Alpine Areas: The Status of Our Knowledge, ” USDA Forest Service Research Paper

RM-138, 1975.

Pereira, H., Land Use and Water Resources

(Cambridge, England: Cambridge University

Press, 1973).

18. Rockwood, D. M., “A Review of Operational

Experience With the SSARR Model,;’ Proceedings: Modeling of Snowcover Runoff, S. C. Colbeck and M, Ray (eds.), U.S. Army Cold Regions

Research and Engineering Laboratory, Hanover, N. H., Sept. 26-28, 1978, pp. 387-396.

Schaefer, V., “The Production of Ice Crystals

in a Cloud of Supercooled Water Droplet s,’ S(;ience 194, 1946, pp. 457-459.

Sopper, W., Watershed Management, Water

Suppl~/ Augmentation b~~ Watershed Management in Wildland Areas, report for National

Water Commission (Springfield, Va.: National

Technical Information Service, 1971).

21. Vonnegut, B., “Nucleation of Supercooled

Water Clouds by Silver Iodide Smokes, ” Chem.

Re~., 1949, pp. 277-289,

22. Warburton, J., “Atmospheric Water Resour(; es

and Its Augmentation, ” OTA commissioned paper, April 1982.

23. Warburton, J., personal communication, 1982.

24. Williams, Kenneth, “Interagency Coordination

25

in Water Supply Forecastin~: Pr-ogress and Opportunities, ” 47th Annual Meeting, Water Sno~a

Conference, Apr. 1820, 1979, Sparks, Nev., pp.

112-115.

Williams, M., personal communication, 1982.
— .

Technologies

AffectingSurfaceWater

Storage and Delivery
—

Page

The Water Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

The Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Technologies That Augment Water Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Technologies That Conserve Existing Water Supplies., . . . . . . . . . . . . . . . . . . . . . . . . . . 191

Vegetation Management in and Near Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

Chapter VII References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

List of Tables

Table No. Page

41. Reservoirs in the Western River Basins With at Least 5,000

Acre-ft of Storage Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

42. Features of U.S. Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

43. Changes in the Colorado River, Grand Canyon National Park,

as a Result of Glen Canyon Dam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

44. The Effects of Glen Canyon Damon Animal and Plant Life in

the Colorado River, Grand Canyon National Park . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

45. Methods of Converting Saline Water to Freshwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

46. Desalting Plants, by Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

47. Major Seepage Losses From Western Rivers, 1975 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

48. Tradeoffs Between Agricultural and Wildlife Practices:

Californians Sacramento Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

49. Southwestern Birds That Rely on Wetland and Riparian Habitats . . . . . . . . . . . . . . . . 201

50. Widespread Phreatophytes of the Western United States . . . . . . . . . . . . . . . . . . . . . . . . 202

51. Major Aquatic Weeds and Extent of Total U.S. Infestation . . . . . . . . . . . . . . . . . . . . . . 204

52. Restrictions on the Use of Aquatic Herbicides. ..., . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

List of Figures

Figure No, Page

38. General Scheme of a Desalting Plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

39. Water Imports and Exports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

40. interstate Water Transfer Routes Assessed by the U.S. Army Corps of Engineers . . 190

41.irrigation Water Distribution Procedure, Kings River, Calif. . . . . . . . . . . . . . . . . . . . . . 192

42. A Compartmented Reservoir in Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

43. Evaporation From Compartmented Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

44. Some Riparian Plants, Called Phreatophytes, Tap Ground Water. . . . . . . . . . . . . . . . . 201

45. Cross-Section of Brazes River, Tex., Before and After Saltcedar Invasion . . . . . . . . . 204
Chapter VII

Technologies Affecting Surface

Water Storage and Delivery

In the Western States, where demand for water often exceeds supply, additional surface

water can be made available by: 1) increasing

the total amount of water in storage, or 2) conserving existing water supplies. Conservation

methods, which can often be applied relatively easily, hold promise for short-term changes

in water use, Methods that increase the amount

of water in storage require significantly larger

investments of time and money and may take

generations to implement.

This chapter considers a variety of technologies that affect surface water storage and delivery. Methods that increase the total amount

of water in storage include desalination, interbasin transfers, and new water projects. Several commonly discussed water-conservation

technologies are also discussed including flexible irrigation delivery systems, seepage and

evaporation control, and vegetation management.

This chapter focuses on those technologies

that have potential for sustaining supplies of

surface water. The effects of widespread adoption of these practices by agricultural producers, however, are difficult to judge, and

quantitative analyses are lacking. Debate continues regarding their technological potential,

their economics of use, and the legal and social

implications of their application.

THE WATER SETTING

Natural streamflow and precipitation seldom

meet agricultural demands for irrigation,

household, and stock water in U.S. arid and

semiarid regions. Therefore, Native Americans

and settlers devised various ways to manage

their water supplies early in U.S. history. Some

of these methods were relatively simple and involved collecting precipitation and runoff for

use when other water sources failed (see discussion of runoff agriculture in ch. VI). Later,

more elaborate systems of reservoirs and canals were built to store runoff, sustain downstream flow during dry periods, and convey

water to irrigation users. Also, multipurpose

reservoirs were built to control floods, maintain fish and wildlife habitat, and supply electrical power and recreation.

These and other developments have altered

the hydrologic cycle. Series of large reservoirs

now regulate the amount and timing of surface

water flow for much of the length of several

Western river systems. Natural runoff has been

reduced by 100 million to 150 million acre-ft

annually (ch, III). Smaller scale developments

also have affected surface water quality, Some

methods for restoring riparian vegetation decrease sedimentation and increase water storage, Changes in ground water use have also affected surface waters. Ground water pumping

from the Ogallala aquifer has lowered water

tables and decreased surface water flow in Nebraska and western Kansas.

181
182 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

Technologies

Water

Storage Facilities

. —

That Augment

Supplies

culture encourages development of smal

watershed projects for soil and water conser

vation and flood control. The U.S. Geologica

INTRODUCTION

Three Federal agencies have authority over

the extensive system of Western water-storage

facilities. The U.S. Army Corps of Engineers

and the Department of the Interior’s Bureau

of Reclamation are charged with developing,

managing, and conserving water resources.

Both agencies’ missions include supplying

water for municipalities, industry, irrigation,

recreation, hydroelectric power, and fish and

wildlife. In addition, the Corps, builds and

operates projects for flood control, hurricane

protection, and navigation. The Bureau of Reclamation, initially authorized to provide irrigation water, operates only in the 17 Western

States,

In addition to these groups, the Soil Conservation Service of the U.S. Department of AgriSurvey maintains a large collection of data on

hundreds of lakes, reservoirs, and other surface waters, Finally, State governments have

built storage facilities. For example, California

designed, financed, built, and operates one of

the world’s largest multiple-purpose reservoirs

at Oroville Dam.

A complex system of both large and small

reservoirs exists as a result of these waterdevelopment projects. The reservoir storage capacity in the Western river basins is about 79

percent of the U.S. total (table 41). These storage facilities include a few very large dams and

reservoirs that contribute much of the total

storage capacity, a sizable number of mediumsized reservoirs, and even more farm and

ranch ponds (table 42).

These reservoirs are managed to permit more

convenient and efficient use of available water

Box L.—Dams and the Western Spirit

Stored water: to some it makes the desert bloom; to others it is sacrilege. Our feelings about

dams reflect our most fundamental values:

Hoover Dam, show piece of the Boulder Canyon project, the several million tons of concrete

that made the Southwest plausible, the fait accompli that was to convey, in the innocent time

of its construction, the notion that mankind’s brightest promise lay in American engineering. Of

course the dam derives some of its emotional effect from precisely that aspect, that sense of being

a monument to a faith since misplaced , . . .—Joan Didion, 1970

Growing upon a farm that had been homesteaded by his grandfather in the eighteen-seventies,

[Bureau of Reclamation Commissioner] Dominy often enough saw talent and energy going to waste

under clear skies . . . . When Dominy was eighteen years old, a big thing to do on a Sunday was

to get into the Ford. . . and go out and see the new dam. Eventually he came to feel that there

would be, in a sense, no West at all were it not for reclamation.—John McPhee, 1971

SOURCES: Excerpted from: Joan Didion. “At the Dam,” The White Album (NeW York: Simon & Schuster, Inc., 1979), 1970, p. 199. John McPhee, Encounters

With the Archdruid [NeW York: Farrar, Straus & Giraux, inc., 1971), pp. 158-159.
Ch. VII— Technologies Affecting Surface Water Storage and Delivery . 183

Table 41.— Reservoirs in the Western River Basins With at Least 5,000 Acre-ft

of Storage Capacity

Storage Evaporation

Number of Natural capacity losses Other

Region reservoirs flow (000 acre-ft/yr) losses

RIO Grande . . . . . . . . . . . . . . . . ... . . . . . 23 2,670 3,958 816 53

Arkansas-White-Red ., . . . . . . . . . . . . . . . . 14 1,440 1,321 113 48

Missouri . . . . . ... . . . . . . . . . . . 105 23,880 26,005 1,108 57

Upper Colorado . . . . . . . . . . . . . . . . . . . . . 40 15,130 33,083 766 209

Lower Colorado . . . . . . . . . . . . ... . . . . 27 2,650 35,883 1,369

Great Basin . . . . . . . . . . . . . . . . . . . . . . . .

—

48 8,350 4,237 1,645 204

California/South Pacific . . . . . . . . . . . . . . . 221 75,890 36,931 1,323 4,148

Columbia/North Pacific . . . . . . . . . . . . . . 201 248,350 42,734 4,577 4,896

Texas-Gulf . . . . . . . . . . . . . . . . . . . . . . . . 0 10 0 12 —

SOURCE U S Department of the Interior, Critical Water Problems Facing the Eleven Western States (Washington, D C U S

Government Printing Off Ice, April 1975) pp 43, 45-46, tables 11-28-30
184 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

Table 42.—Features of U.S. Reservoirs

Reservoir size Storage capacity Part of total

(1,000 acre-ft) Number (1 ,000 acre-ft) U.S. storage (percent)

More than 10,000 . . . . . . . . . . . . . . 5 117,000 25

2,000 to 10,000 . . . . . . . . . . . . . . . . 26 74,000 16

5 to 2,000 . . . . . . . . . . . . . . . . . . . . . 1,600 168,000 37

0.05 to 5 . . . . . . . . . . . . . . . . . . . . . . 47,500 91,000 20

Less than 0.05 . . . . . . . . . . . . . . . . 1,843,000 10,000 2

Total . . . . . . . . . . . . . . . . . . . . . . . 1,892,131 460,000 100

SOURCE U S Water Resources Council, The Nation’s Wafer Resources 1975-2000 (Washington, D C U S. Government Print.

ing Office, 1978), vol 2, pt IV, table IV-3

supplies by downstream users. They may be

used in conjunction with other surface or

ground water facilities such as pumps, pipelines, wells, and canals. Both large and small

facilities may have multiple uses. For example,

farmers and ranchers sometimes store water

for frost control, fire protection, domestic use,

spraying fertilizers or pesticides, or recreation.

Onfarm irrigation reservoirs are used to:

1.

2.

3.

4.

5.

6.

store runoff for use during dry periods,

store water during periods of low demand

or at times when irrigation is not possible,

store water overnight,

regulate flows or otherwise match elements of an irrigation system,

store irrigation runoff, called “tailwater,”

and

control water levels in adjacent areas.

Ranches often have small stock-watering reservoir systems developed from natural or artificial impoundments. These may be used to increase stocking rates by: 1) lengthening the

grazing season, 2) spreading use more evenly

over the range, or 3) opening new land to grazing.

ASSESSMENT

Construction technologies for large and small

reservoirs are well developed. Recent advances

include the use of rolled concrete and soil cement and improved methods for placing cutoff

walls. Modern dams are safer and more durable than their early 1900 counterparts. Technologies to manage reservoirs are advancing

rapidly. New means exist to gage and time

water flows and to monitor water movement

throughout even the largest river systems. In

Photo credit. USDA Soil Conservation Service

This 33-ft-diameter stock-water tank supplies ground

water for two herds of cattle near Sterling, Colo.

order to assess the future of surface-water storage facilities, therefore, it is necessary to look

beyond available technology.

The Federal Government is a major reservoir

owner as a result of past investments. For example, the Federal Government owns over

2,000 dams, ranging in size from small diversions to huge multipurpose projects such as the

Central Valley Project in California. In addition, 50-percent Federal cost-sharing spurred

farm- and ranch-pond construction; by 1964,

one-fourth of all U.S. farms and ranches had

privately owned ponds, pits, reservoirs, or

earthen tanks. Over 2 million such structures

were built, but they were not heavily concentrated in the West (15).

The Federal Government has an investment

of more than $26 billion in completed waterresource projects and annual construction and

rehabilitation costs for the federally owned
Ch. VIII Technologies Affecting Surface Water Storage and Delivery 185

—

Box M.—Managing the Columbia River: CROHMS

The Columbia River Operation Hydromet Management System (CROHMS) is an example of

the integrated management of a river and its reservoirs to produce a more efficient use of the region’s

water. It is based on new and advanced technology: a central computer with access to hydrological

data gathered throughout the Columbia River Basin, data processors and displays, and mathematical

models of river and reservoir behavior. Taken together, these components simplify decisionmaking on reservoir management at 80 dams used for hydroelectric power generation, flood control,

irrigation water supplies, and recreation.

A number of independent data-collection systems forward information to CROHMS, where

data is processed and made available to all potential users. Cooperating Federal agencies include

the Bonneville Power Administration, the U.S. Army Corps of Engineers, the Bureau of Reclamation, the National Weather Service, the Geological Survey, and the Soil Conservation Service (SCS).

The Province of British Columbia also participates. Several U.S. agencies collect and provide data

from remote weather stations such as SCS Snotel and Bonneville’s Hydromet. The computer software is another important aspect of CROHMS. These programs are still under development at

the center in Portland, Oreg., but they will eventually include a complex data-management system,

methods for data validation, and various mathematical models for forecasting streamflows and

reservoir regulation. Eventually, automation will virtually eliminate the cumbersome manual tasks

of preparing data for the computer.

CROHMS represents an attempt to forecast and regulate the flow of a major river system by

computerized data collection, analysis, and modeling. If successful, this approach should improve

the efficiency with which the water in a river basin can be managed. This, in turn, should make

more equitable the allocation of water among potentially competing users.

SOURCE: Speer, et al., "CROHMS–An Example of Successful Interagency Coordination in Data Collection,” 47th Annual Meeting, Western Snow Conference

(Reno, Nev., 1979), pp. 102-107.

projects are high. In fiscal years 1981 and 1982,

combined appropriations for the Army Corps

of Engineers and the Bureau of Reclamation

for these purposes totaled $1.7 billion and $1.9

billion, respectively. Only a portion of the

Corps’ budget was spent in the West, but the

entire Bureau of Reclamation budget is related

to Western water developments. Long-term

U.S. Treasury borrowing finances these projects almost totally (39).

The benefits of these expenditures have been

sizable, The larger projects made it possible to

plan, build, and finance works on the scale required for main-stem Western rivers. Sometimes these have provided irrigation water,

higher farm incomes, flood control, municipal

water supplies, reservoir recreation, and power

generation, For example, irrigation has made

agricultural land use more productive on a peracre basis.

There have also been substantial costs in addition to those noted above, Scenic and productive lands have been inundated, capital and

labor have been diverted, families and towns

have been displaced, fish and wildlife habitat

has been altered, and towns have faced “boom

town” social problems.

In the past, these large, federally funded water projects were approved on an ad hoc basis

and met with little opposition (7). This situation no longer exists. Project selection, authorization, and construction now receive increased attention (see ch. V).

Barriers to new large-scale developments are

physical, economic, and environmental. The

physical sites most suitable for large-scale

storage facilities have been used. The remaining sites may be less favorable for large dam

construction and more distant from major pop25-160 0 - 1 3 : QL 3
186 Water-Related Technologies for Sustainable Agriculture — ———

ulation centers, thus decreasing their value for

recreation, an important benefit for multiplepurpose projects.

The economic costs of large projects have escalated, making conservation, improved management, and other nonstructural methods

more attractive for making more water available. In addition, the economic costs and benefits of existing projects have been called into

question. The analytical techniques used by

project sponsors to determine costs, associated

benefits, and interest and payback rates from

users sometimes have been criticized as inaccurate and misleading (8,38).

Also, today it is clear that large reservoir construction may result in major environmental

effects and hazards (tables 43 and 44). Development around Lake Powell, for example, has increased air pollution, noise pollution, and litter (19). The majority of dams and reservoirs

in many States became operational in the early

part of the 1900’s. Because previous water planners focused on project construction, not operation and maintenance, many expenditures to

ensure the safety and efficient management of

old facilities have been postponed. The total

cost of these repairs could reach several billion

dollars (39).

in U.S. Arid and Semiarid Lands

— .— — —

Because of these constraints, many experts

expect that the Federal role in building and

operating new large-scale water projects will

decline sharply. New storage facilities are likely to be smaller, and their construction may depend entirely on private or non-Federal public

investment or innovative cooperative arrangements between private and public developers

or among Federal, State, and local governments. State bonds, revenue-sharing, property taxes, user charges, and joint ventures may

become alternative means of raising funds. In

Wyoming, for example, when the State Engineer declared a reservoir unsafe if more than

one-half full, private investors agreed to renovate the reservoir in return for the first new

5,000 acre-ft of storage (l).

It is not clear to what extent farmers and

ranchers will be able to take advantage of arrangements such as these. If Bureau of Reclamation irrigation projects that are based on irrigators’ ability to pay contribute only about

19 percent of all costs, it is unlikely that private

financing at higher levels will be profitable

(17,28), The hydrologic effects are also not well

known. The trend to construction of a larger

number of smaller reservoirs may reduce the

amount of water stored throughout the region.

Table 43.—Changes in the Colorado River, Grand Canyon National Park,

as a Result of Glen Canyon Dam

Feature Pre-dam Post-dam

Appearance of water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Red Green

Average annual sediment load . . . . . . . . . . . . . . . . . . . . . . . 140 million tons 20 million tons

Annual variation in water discharge . . . . . . . . . . . . . . . . . . High, seasonal Low, daily

Annual water temperatures . . . . . . . . . . . . . . . . . . . . . . . . . 32-85’ F 42-48” F

Light penetration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 inches . River bottom

SOURCE S W Carothers and R DoIan, Dam Changes on the Colorado River, ” Natural History, vol 91, 1981, pp 75-83

Table 44.—The Effects of Glen Canyon Dam on Animal and Plant Life in the

Colorado River, Grand Canyon National Park

Results

Alteration Increases Decreases

Water discharge . . . . . . . . . . . . . . Streamside plants, animals Wetland breeding habitat

Light penetration . . . . . . . . . . . . . Mats of green algae

Water temperature . . . . . . . . . . . . Exotic fish (19 species) Native fish (8 species)

Overall changes . . . . . . . . . . . . . . Complex terrestrial food webs Complex aquatic food

webs

SOURCE S W Carothers and R DoIan, “Dam Changes on the Colorado River, ” Natural History, vol 91, 1981, pp. 75-83
Ch. VII—Technologies Affecting Surface Water Storage and Delivery . 187

—— -— ——

With higher surface to volume ratios, these

reservoirs might lose larger percentages of

their water by evaporation and seepage.

DesaIination

INTRODUCTION

As municipalities, industries, and irrigated

agriculture continue to grow, demand for

freshwater is expected to increase in the arid

and semiarid regions of the West. Desalination

is one technique that can supplement freshwater supplies by removing salt from ocean water

or by improving the quality of salt-degraded

water. In some cases, complete desalination

may not be necessary. Salt-tolerant plants (ch.

IX) and corrosion-resistant hardware may allow brackish water to be used. In addition,

saltwater or desalination wastes may have

direct uses. For example, some solar-powered

greenhouses use saline water for heating and

cooling. Moreover, seafood aquiculture depends on saltwater (ch, XI), and salt-gradient

solar ponds can supply economical electricity

and heat (12).

Of the many desalting techniques that exist,

there are four general methods: 1) distillation,

2) membrane processes, 3) crystallization, and

4) chemical processes (table 45). General desalting operations are similar (fig. 38). Water is delivered and mechanically screened to remove

suspended solids and debris. Subsequent processing results in two products: a disposable

brine stream and a product stream which may

be treated further, depending on its intended

use.

Desalting plants exist throughout the world

and are located in arid, semiarid, and humid

climates. They range in capacity from a fraction of an acre-foot to hundreds of acre-feet per

day. In the United States, a reported 637 plants

produce 760 acre-ft/day or approximately 15

percent of the worldwide output (table 46).

One-half of these plants are located in California, Florida, Texas, and Arizona.

One of the largest U.S. facilities will be the

Bureau of Reclamation’s Yuma (Ariz.) desalting

plant, Scheduled to be operational by the end

of 1987, it will produce 0.1 million acre-ft of

—

Table 45.—Methods of Converting Saline Water to

Freshwater

Distillation processes:

—

Examples:

Multistage flash distillation

Vertical tube distillation

Multieffect multistage distillation

Solar humidification

Attributes:

Most widely used

Energy intensive and costly

Results in “ultrapure” water

Favored for seawater

Membrane processes:

Examples:

Reverse osmosis

Electrodialysis

Transport depletion

Piezodialysis

Attributes:

Favored for brackish water

Require pretreatment to remove pollutants

Potentially energy efficient

Increasingly popular

Crystallization processes:

Examples:

Vacuum freezing-vapor compression

Secondary refrigerant freezing

Eutetic freezing

Hydrate formation

Attributes:

Experimental stage

Minimize corrosion

Potentially energy efficient

High recovery without major pretreatment

Chemical processes:

Example:

Ion exchange

Attributes:

Less costly “ultrapure” water

Useful for low-salinity water

SOURCES U S Department of Interior, The ABC of Desalting (Washington, DC.

U S. Government Printing Office, 1977), p 2, U S General Account.

ing Office, “Desalting Water Probably WiII Not Solve the Nation’s

Water Problems But Can Help” (Washington, D C General Account.

ing Office, CED-79-60, 1979)

water per year using a membrane process (18).

The plant will treat Colorado River water before it passes to Mexico, as required by treaty.

ASSESSMENT

Desalination by many methods is technically feasible, at least for small amounts of water.

It has proven to be a reliable way to meet specialized water needs but requires further development before it can produce low-cost freshwater.

High costs are the major current limitation

to use of desalination, although brine-disposal
. — —

188 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —.

Figure 38.—General Scheme of a Desalting Plant

●

Desalting plant

I

Table 46.—Desalting Plants, by Location

Number Plant capacity

Region of plants (acre-f t/day)

United States . . .; . . . . . . . . . . . . . 637 760

U.S. Territories . . . . . . . . . . . . . . . . 34 78

North America (outside U. S.) . . 58 51

Central America and Caribbean 66 123

South America . . . . . . . . . . . . . 41 30

Great Britain and Ireland . . . . . . 63 51

Europe . . . . . . . . . 256 380

Africa . . . . . . . . . . . . . . . . . . . . . . 244 438

Arabian Peninsula and Iran . . . . 599 3,485

Asia and India . . . . . . . . . . . . . . . . 172 292

Australia and the Pacific . . . . . 19 9

U.S.S.R. . . . . . . . ... . . . . 18 202

All regions . . . . . . . . . . . . . . . . . 2,207 - 5,899

SOURCE Techno-Economic Services, Desalting Plants Inventory Report No 7

(Honolulu, Hawaii Techno-Economic Services and Ipswich, Massachusetts Water Supply Improvement Association, May 1981), p 9, table 1

problems also could be troublesome. Costs and

conversion rates for the various desalting processes vary widely. They include capital costs

based on the process type, plant capacity, feedwater type and salinity, pretreatment required,

product salinity, site-related costs for land, and

operating, maintenance, and replacement

costs.

.- — —-

These considerations limit production of desalted water to municipalities and industries

and exclude most agricultural uses (5). For example, desalted municipal water costs about

$1,300/acre-ft for seawater and $325/acre-ft for

brackish water. Municipal water from conventional sources costs about $13/acre-ft (37). Some

irrigators pay $0.27 to $9.82/acre-ft of water

(39).

Use of expensive desalted water for irrigation would seem feasible where high-value,

high-yield crops could be grown under a yearlong or nearly year-long growing season, or

where no other water was available. Under

such conditions, farmers could take advantage

of the year-round water production from a capital-intensive desalting plant. Precise farm

delivery and crop application would be required because of the high water costs. Where

desalination is required because of agricultural

salt buildup (e. g., the Yuma plant), agriculture

cannot carry desalination costs alone.

Interbasin Transfers

INTRODUCTION

Water transfers from one river basin to another for irrigation, municipal and industrial

use, hydroelectric power, and other purposes

have existed throughout the world for centuries. In the Western United States, regional

transfers of water from the Colorado River Basin to other basins—e.g., the Colorado-Big

Thompson Project—have been in operation for

many years (fig. 39). Current attention focuses

on proposals to transfer water from areas of

supposed surplus (e. g., Alaska, the Missouri

River) to Western stream systems for irrigation

use.

ASSESSMENT

Results of the recently completed Six-State

High Plains-Ogallala Regional Resources study,

authorized by Congress in 1976, highlight the

complexity of the interbasin transfer issue. As

part of the overall study, Congress directed the

U.S. Army Corps of Engineers to investigate

the potential for augmenting water supplies in
—. .

Ch. VII—Technologies Affecting Surface Water Storage and Delivery ● 189

-——

Figure 39.—Water Imports and Exports

n

the region through interbasin transfers from

“adjacent areas. ” The Corps examined four

plans in detail. Two proposed to divert water

from either Fort Randall, S. Dak., or St. Joseph,

Mo., on the Missouri River and convey it to

eastern Colorado or Dodge City, Kans. Two

other proposals considered tapping water at

Various points along the Arkansas, White,

Ouachita, and Red Rivers in Arkansas and the

Sulphur and Sabine Rivers in Texas and transferring this water to storage points in Texas

(fig < 40).

The Corps concluded that construction of canal systems capable of transporting 9 million

acre-ft of water was feasible from an engineering standpoint. However, there were numerous

economic, physical, and environmental barriers to implementation (z). First, the cost o f

irrigation water obtained from an interbasin

transfer was prohibitively expensive and

ranged from $226 to $434/acre-ft (1977 dollars),

exclusive of costs beyond the terminal reservoir. Furthermore, with the high energy requirements needed for operation, water costs

were projected to escalate significantly a s

energy costs increased, Second, no surplus water existed in the basin of origin, given present

and future needs of the source basin. Third,

construction of any of the routes would result

in major environmental impacts. These projected effects included altered flow regime of

the source streams, inundation of large areas

of productive land for source and terminal stor-
190 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 40.– Interstate Water Transfer Routes Assessed by the U.S. Army Corps

Legend:
Ch. VII—Technologies Affecting Surface Water Storage and Delivery . 191

age, conversion of large amounts of agricultural land to other uses, and disruption of wildlife

migratory patterns.

Other considerations and possible limitations

to interbasin transfer, though not identified by

High Plains study, include:

treaty requirements and restrictions—e. g.,

the Mexican Water Treaty;

commitments under the Wild and Scenic

Rivers System;

Federal and State statutory prohibitions

against interbasin transfers, particularly

interstate;

vested rights to the waters of the source

stream;

allocations under interstate compacts;

uncertainties concerning Federal reserved

water rights and Indian water rights;

lack of comprehensive, multipurpose, upto-date regional planning encompassing

both the source river basin and prospective

affected area;

lack of State water plans in many States;

lack of generally accepted projections of

future consumptive water demands in the

source basins and receiving States; and,

public opposition in the source basins to

water transfer.

In the present and foreseeable future, political, financial, legal, and institutional considerations probably will preclude the use of extensive interbasin transfers of water to sustain irrigated agriculture in arid and semiarid regions

of the West. Major changes in Federal and

State laws and policies; provisions of large

amounts of Federal and State funds; comprehensive, multipurpose, regional planning for

water and other resources; and major changes

in public perceptions and attitudes would be

necessary before such transfers could be implemented. For example, the Colorado River

Basin Project Act of 1968 (Public Law 90-537)

prohibited planning by Federal agencies or

with Federal funds for water diversions from

the Columbia River Basin for use outside that

basin. The initial 10-year moratorium has since

been extended for another 10 years by the

Reclamation Safety of Dams Act of 1978

(Public Law 95-578).

— . —

Technologies That Conserve

Existing Water Supplies

Flexible Delivery Systems

INTRODUCTION

An adequate water supply is a critical aspect

of surface water management. Timely water

delivery is a second key element. Onfarm and

off-farm irrigation systems that use surface

water have two major features: a physical

system of storage and conveyance and a managing organization to oversee distribution.

Physical components generally include one or

more storage reservoirs, diversion works to

channel water into the conveyance system, a

conveyance system with structures for flow

control, and a distribution system that brings

water to the individual user. Throughout the

system, control gates or pumps regulate water

levels and control the quantity of water being

discharged through or into a particular structure.

The Federal Government builds and operates

many reservoirs and major conveyance systems in the Western States, but many non-Federal public and private systems also exist, If

Federal water is to be used for irrigation, it is

sold to irrigation districts and/or canal CO Illpanics. The exact arrangements for water distribution to individuals vary considerably from

place to place, They include procedures that

allot water based on crops, farm location,

shares owned in the irrigation system, time of

settlement, and other factors (fig. 41),

Operations of surface water systems are complex. Where sufficient supplies of water exist

and conveyance systems are capable of transporting variable flows, a water system can be

operated to meet all users’ potential demands.

However, in most arid and semiarid regions,

systems that respond to unregulated demand

are not feasible because water supply or system

capacity is limited. Here, systems that are designed around supply have been more common.

The amount and timing of surface water flow

in a supply-type system is controlled upstream.

Federal or local project operators release water
192 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 41 .—Irrigation Water Distribution Procedure, Kings River, Calif.

Water Supply to Canals

Streamflow diverted into canals according to water rights held by irrigation

units.a Since completion of Pine Flat Dam, most water is captured in reservoir space and released on order of irrigators.

Direct from stream Reservoir

Some units buy surplus water from Central Valley Project

to supplement their supply.

f

Deliver water from canals to farms. Water delivered at constant

rate of flow.
—.

Ch. VII Technologies Affecting Surface Water Storage and Delivery ● 193

from an upstream source based on “water orders” that anticipate downstream needs, The

water then moves into a main canal (managed

by Federal or local organizations), through a

system of smaller canals, and is delivered to

the farm. If farmers or districts decide not to

use the water, it continues to move through the

system and is spilled at the lower end of the

canal.

Districts have formal rules and regulations

for water distribution. Often, delivery schedules are developed in advance and are fixed for

time and length. Adjustment in timing, duration, or quantity of water application is limited.

For example, if several users are allowed to

shut off water, flow along the entire canal sys-

— — ———

tern changes, and canal banks may overtop.

while these rules allow close control of water

in the system and enable officials to maintain

accurate records of water deliveries, the

amount and timing of water deliveries facilitate

water distribution rather than accommodate

crop needs. This situation limits the amount

of water conservation that is possible. A variety

of technologies for providing improved flexibility in water delivery are being examined,

Automated Upstream Control.—Stabilization of water levels in a conveyance system is

difficult with conventional, manually operated

check gates. In recent years, many irrigation

districts have installed automated gates that

maintain a constant water level regardless of

Box N.—Water Delivery: Pulling It Down and Putting Some Over the Hill

I suppose it was partly the memory of that [raft trip] that led me to visit, one summer morning in Sacramento,

the Operations Control Center for the California State Water Project. Actually so much Water is moved around

California by so many different agencies that maybe only the movers themselves know on any given day whose

water is where . . . , They collect this water up in the granite keeps of the Sierra Nevada and they store roughly

a trillion gallons of it behind the Oroville Dam and every morning, down at the Project’s headquarters in

Sacramento, they decide how much of their water they want to move the next day. They make this morning

decision according to supply and demand, which is simple in theory but rather more complicated in practice. In theory each of the Project’s five field divisions . . . places a call to headquarters before 9 a.m. and

tells the dispatchers how much water is needed by its local water contractors, who have in turn based their

morning estimates on orders from growers and other big users. A schedule is made. The gates open and close

according to schedule. The water flows south and the deliveries are made.

In practice, this requires prodigious coordination, precision, and the best efforts of several human minds

and that of a Univac 418. In practice it might be necessary to hold large flows of water for power production,

or to flush out encroaching salinity in the Sacramento-San Joaquin Delta, the most ecologically sensitive point

on the system. In practice a sudden rain might obviate the need for a delivery when that delivery is already

on its way. In practice what is being delivered here is an enormous volume of water, not quarts of milk or

spools of thread, and it takes 2 days to move such a delivery down through Oroville into the Delta, which

is the great pooling place for California water and has been for some years alive with electronic sensors and

telemetering equipment and men blocking channels and diverting flowS and shoveling fish away from the

pumps. It takes perhaps another 6 days to move this same water down the Calfornia Aqueduct from the Delta

to the Tehachapi and put it over the hill to Southern California. “Putting some over the hill” is what they

say around the Project Operations Control Center when they want to indicate that they are pumping Aqueduct

water from the floor of the San Joaquin Valley up and over the Tehachapi Mountains. “pulling it down” is

what they say when they want to indicate that they are lowering a water level somewhere in the system.

They can put some over the hill by remote control from this room in Sacramento with its Univac and its

big board and its flashing lights . . . [and] with its locked doors and its ringing alarms and its constant printouts of data from sensors out there in the water itself. . . . I stayed as long as 1 could and watched the system

work on the big board with the lighted checkpoints. The Delta salinity report was coming in on one of the

teletypes behind me. The Delta tidal report was coming in on another. The earthquake board, which has been

desensitized to sound its alarm (a beeping tone for Southern California, a high-pitched tone for the north)

only for those earthquakes which register at least 3.0 on the Richter Scale, was silent. I had no further business

in this room and yet I wanted to stay the day . . . ,

SOURCE: Excerpted from: Joan Didion, “Holy Water,” The White Album [New York Simon & Schuster, Inc , 1979], 1977, pp 60-62, 66.
194 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

water flow. These gates do not change the basic

operation of the system. For example, if water

demand increases upstream, downstream gates

automatically close to maintain a constant

water level and users on the downstream end

may not receive enough water. Conversely, a

decrease in upstream demand automatically

opens downstream gates to allow extra flow to

pass. However, if supply exceeds demand, water may spill at the lower end of the canal system,

Downstream Control Systems.—Downstream control of irrigation water (“demand delivery”) is a second category of canal control.

Downstream control compares to water delivery in municipal systems where water is available any time an individual turns on the tap

and at any flow rate, up to the limits of the piping system or regulation. A downstream controlled system automatically responds to the

opening and closing of farm gate turnouts. If

an irrigator opens a turnout gate in these systems, a water wave is transmitted upstream to

a gate, which in turn opens to release extra water. An opposite reaction occurs when the turnout is shut off.

Downstream control has been achieved in

parts of irrigation projects in the United States,

and complete systems have been constructed

in Morocco and Tunisia. Two types of downstream control have been used. In one type, a

series of level-top canals are connected by controls that respond to changes in downstream

water levels, If water is discharged from the

downstream end of a pool, for example, the water surface drops at that end and the resulting

wave causes the upstream canal gate to open

wider. A second, more rapid response, downstream control relies on multiple-sensing devices to take continuous readings throughout

a canal system. Data are relayed to a computer

in the central office and gates are adjusted on

the upstream end.

Regulating Reservoirs Along Irrigation Canals.—An alternative to upstream or downstream control is to use one or more regulating

reservoirs along the irrigation canal to buffer

imprecise upstream deliveries and to allow a

demand schedule to be implemented in a large-

—

ly upstream-controlled system. Irrigation water

can be stored until it is needed, and response

time to irrigator demand can be shortened.

Combination Control.—It is not necessary

to have downstream control structure s

throughout the canal system to deliver water

to farm turnouts on a demand schedule. Upstream control structures on the upper one-half

or two-thirds of a system and a regulating reservoir below this point can be an economical alternative. Demand scheduling can then be implemented on the lower end of the conveyance

system.

Centralized Scheduling Services.-The U.S.

Bureau of Reclamation has been experimenting

with an extension of downstream control that

predicts water requirements in individual

fields based on weather and crop data. Water

requirements for the aggregate system can then

be predicted and the complete operation can

be prescheduled,

Onfarm Reservoirs.—Where irrigation districts deliver water on a fixed schedule, farmers

may build onfarm reservoirs at the turnout

point to store water until it is needed.

ASSESSMENT

Flexible delivery schedules are relatively new

in concept, design, and implementation. For

example, level-top and newer rapid-response

downstream control methods remain experimental, design refinements are still required,

and as yet, capital and labor costs remain high

(31).

The main advantage of these delivery schedules is the choice they provide in duration, frequency, and quantity of water delivered to ensure that the crop receives water when needed

but not in excess of the amount required. For

example, automated upstream control provides

irrigators with limited flexibility in operation

of turnout flows (discharge openings). Downstream control allows an irrigator to have water

when it is needed and simplifies canal company operations, since farmers determine delivery schedules. Combined methods of control

have advantages of several control methods

and generally reduce the risk of spillage and

under-irrigation (4).
Ch. VII—Technologies Affecting Surface Water Storage and Delivery . 195

— . —

Advocates of these control methods note

many benefits for individual irrigators. These

include: higher crop production per unit of

water applied; higher crop production per acre;

less surface runoff, erosion, and sedimentation;

less deep percolation and attendant loss of fertilizers and pesticides; less seepage; less ground

water use; and reduced pumping requirements.

With better control, any excess water may remain in the system with the result that instream

flow may increase. Because less polluted water

is returned to the stream, water quality may improve and deposition of suspended sediment

in reservoirs and streams may decrease (20,40).

Delivery arrangements based on considerations of technical efficiency alone may not be

easy to implement. Some factors that restrict

implementation include (24):

Economic limitations.’ Some irrigation

systems are old and rehabilitation to achieve

more flexibility is prohibitively expensive.

Others, such as onfarm reservoirs, are expensive to build and maintain and take land out

of crop production.

Training and education needs of engineers,

managers, and designers: The expertise required for some onfarm measurements of soil

moisture or water application, for example,

may be beyond that which most irrigators have

or want. Some irrigation districts do not have

the capability for automated water forecasting

and management.

Institutional considerations: Water rights

doctrines in the Western States are based primarily on the appropriation doctrine with a

water right tied to specific lands. Many decreed rights may be far in excess of irrigation

requirements, using current or improved technology, but irrigators who use less water on

their farms and ranches may not get the economic benefit of that water, since it becomes

available to the next junior user. For example,

farmers and ranchers may have little incentive

to use downstream controls that could reduce

the amount of water applied to fields unless

economic losses—e. g., those from fertilizer

leaching–can be demonstrated.

Accuracy of water measurement in canals

and soil is an important requirement in flexible delivery systems. For instance, extensive

field measurements are needed to calibrate the

computer programs that predict crop water requirements for centralized scheduling services.

Downstream control systems must be monitored to ensure that requests do not exceed the

capacity of the system. Modern electronic

measurement devices are available for accurate

accounting of water in all parts of the system,

but ensuring that farmers and managers have

access to this equipment and to backup information is difficult.

Responsibility for maintaining water records

is shifting in some areas. For example, Federal

efforts in providing centralized scheduling

services have been criticized as understaffed

and unresponsive to individual requirements.

Private agricultural consultants in some areas

are replacing Bureau of Reclamation irrigation

scheduling services, but this transition is not

without friction (23).

Seepage Control

INTRODUCTION

Seepage occurs through the sides and bottoms of reservoirs and canals. Its extent

depends largely on geology, soils, and topography. Many technologies used to make soils

impervious for water harvesting (ch. VI) also

can be used for seepage control. These include:

1) compacted earth, 2) rigid surfaces, 3) buried

and exposed membranes, and 4) soil sealants.

Each area must be evaluated individually before a control method is chosen. Soil characteristics, operating capacity and flow velocity

of the irrigation canals, structural stability required, water quality, and safety and maintenance needs must all be analyzed.

Assessment

Water “losses” from seepage can be large

enough in some areas to prevent reservoirs

from filling (4). However, estimates of the problem’s magnitude vary widely and are difficult

to make. For example, Morrison and Johns (25)
—..... .- —- . .-

196 c Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— -—. - — — — —

suggest that eliminating seepage from irrigation systems could affect 1.5 million acre-ft of

water. According to another author, consumption and conveyance water losses, including

seepage and water use by riparian vegetation,

account for about 5 percent of usable reservoir

storage in the West (4). An earlier compilation

of data by the Bureau of Reclamation showed

that losses were considerably higher for many

rivers (table 47).

Seepage control only “saves” water on a local

basis, though, and its effects vary widely in different locations. Water lost to seepage is not

lost to downstream users, to organisms in artificial or natural wetlands and streams, nor

to the hydrologic system. For example, seepage

from leaky irrigation systems in some areas

provides ground water recharge. Depending on

conditions, uncontrolled seepage may also result in soil salinization, waterlogging, or erosion of neighboring soils.

Seepage control currently is easier and less

expensive than evaporation control (26). Both

processes are expensive, however, and high

cost is the primary limitation to use. As the

relationship between standing water from inefficient irrigation and wildlife populations is

explored, other limitations may be identified.

In California, for example, applications of irrigation water in excess of plant needs and

seepage from canals have contributed to increases in waterfowl populations. As water
Ch. VII—Technologies Affecting Surface Water Storage and Delivery . 197

Table 47.—Major Seepage Losses From

Western Rivers, 1975

Acre-ft Percent of

of annual total water

Basin seepage diverted .

Missouri River:

Buford, Trenton, ND ... . . . .

Mirage Flats, NE . . . . . . . . . . . .

Buffalo Rapids, MT ... . . . . .

Lower Yellowstone, MT, NE . .

North Platte, WY, NE ., . . . . .

Milk River, MT ., . . . . . . . . . .

Columbia River:

Crescent Lake, OR. . . . . . . . . .

Arnold, OR . . . . . . . . . . . . . . .

Missoula Valley, MT . . . . . . . . .

Umatilla, OR . . . . . . . . . . .

Minidoka Palisades, ID, WY . .

Boise, ID, OR ... . . . . . . . .

Columbia, Basin, WA . . . . . .

Yakima, WA ... . . . . . .

Sacramento River:

Orlando, CA . . . . . . . . . . . . . . . .

Colorado River:

Salt River, AZ . . . . . . . . . . .

Grand Valley, CO . . . . . . . . . . . .

Rio Grande River:

Rio Grande, NM, TX . . . . . . . . .

Middle Rio Grande, NM . . . .

Klamath River:

Klamath, CA, OR . . . . . . . . . . . .

Total . . . . . . . . . . . . . . . . . . . . ——

6,149

6,821

42,478

57,985

542,380

151,967

32,830

8,590

710

60,335

1,457,949

784,655

676,320

520,832

45,066

526,177

59,661

273,301

121,360

265,473

5,641,039

35

46

55

21

43

59

49

38

24

30

24

35

23

24

37

39

18

39

24

28

SOURCE U S General Accounting Off Ice, “More and Better Uses Could be Made

of Billions of GalIons of Water by Improving Irrigation Delivery

System s,” (Washington, D C GAO 77117 Sept 2, 1977). p 15 Original

source U S Bureau of Reclamation Annual Report, 1975

conservation becomes more common, waterfowl are decreasing (35). It is not yet clear how

these tradeoffs will be judged and managed

(table 48).

Of the various types of seepage control, compacted earth linings often are available locally and at low cost. But these linings require

specific soil conditions; when these conditions

are not present, treated canals may continue

to leak.

Rigid surface linings—e.g., concrete, asphalt,

and soil-cement—are chosen when structural

stability is important, such as when soils are

unstable or near municipal areas. Concrete is

most resistant to erosion, which is important

when canals carry water at high velocities.

Concrete-lined structures are susceptible to

frost and chemical damage, though, and preventive features increase costs. Concrete linings may be either poured or applied under

pneumatic pressure (“shotcrete”). The latter is

limited to small canals and mild climates.

Asphalt and asphalt concrete also are effective linings. Asphalt concrete is durable, watertight, and erosion-resistant but requires careful

compaction by large machinery. Therefore, it

is used only in those large reservoirs and canals

where cost is not prohibitive. Asphalt blown

onto soil, then covered with more soil to prevent mechanical damage, is suitable for smaller

structures and is less costly, but also less

durable. Asphalt may also be mixed with other

materials, such as rubber or fiberglass.

A rigid surface lining can also be made of

a water, soil, and cement mixture. This mixture, called soil-cement, has high durability

and low permeability if mixed and applied

properly, It can be made only with relatively

fine-grained soils and requires careful compaction (6),

Many different types of membranes have

been used to line canals, sometimes only experimentally. These include synthetic rubber,

prefabricated asphalt sheets, fiberglass-reinforced polyester, and other types of plastics.

Thin membranes placed on the inside surface

of a canal are exposed to weathering, vandalism, erosion, animals, and weeds. Such liners

require careful ditch preparation to remove

sharp objects and to ensure that the liners lie

flat. Asphalt or plastic liners are usually

covered by about a foot of earth, Asphalt linings have been in place for over 20 years; plastic linings have been used for almost 30 years,

but detailed analysis of their performance covers a shorter period of time. Both are relatively low cost and effective, Rubber has been used

less because it costs about three times as much

as plastic (25),

A wide variety of soil sealants has also been

used to eliminate canal and reservoir seepage,

These agents may physically plug soil pores,

form a distinct impermeable membrane, or

chemically react with soil constituents, Soil

sealants must be nontoxic to humans, animals,

and crops; withstand a broad range of water

quality; and resist breakdown by animals,

equipment, erosion, and water pressure, Var-
Table 48.—Tradeoffs Between Agricultural and Wildlife Practices: California’s Sacramento Basin

Opportunity Agricultural viewpoint Fish-wildlife-recreation viewpoint

Practice

Increase ground ‘-

water pumpage

for water saving Positive Negative Positive Negative Comments

Possibly very large Farmers gain High initial cost;

big energy user

Reduces diversions

from river

May increase percolation

One of two true

means of saving

water in basins

operating independence and dryyear flexibility

Increased dry-year

supply

Increase reservoir

storage

Moderately large None Decreases peak

flows; increases

dry-year summer

flows; enhances

reservoir-type

fisheries

Would tend to

reduce diversions

from the Sacramento River, leavWould flood out

native lands

Opportunity for

true in-basin

water savings

Reduce water applied to rice

Large, possible

several hundred

thousand

acre-feet

Would increase irrigation management costs; increase TDS of

drainage water

Should produce a

large net saving in

applied water use;

save energy and

fertiIity

Would decrease

drain flows,

hence diminish

riparian vegetation and fish

flows, increase

TDS and water

temperatures

Elimination of

berms would reduce wildlife

habitat

No savings would

result unless

storage provided

ing more water

in-channel use

Included above

for

I Level all rice paddies, form rectangles

Included above Would decrease applied water use by

an estimated 5°/0;

increase yield,

reduce water management and harvest costs, increase net profit

Would reduce water

use; increase forage production

Would take land

out of production for one crop

year; require

capital outlay

Now catching on

rapidly in ricegrowing areas

Drain wet mountain meadows;

improve water

management

Small Would require annual maintenance cost; high

original investment

None As time goes on,

practice will be

employed

through the incentive to increase forage

product ion

Must develop

incentives for

districts to take

action; must persuade people

that water-saving

practices are

necessary

Would reduce

wetland habitat

reduce late summer downstream

flows

District practices;

canal lining (reduce seepage);

increased use of

relift pumps,

control ditch

bank vegetation,

clear channels

Large, could reduce district demandsThese practices will

decrease water demands on a district basis; could

increase yields and

decrease fertilizer

needs

Would require

more energy,

capital, and manpower, increase

the unit cost of

water, leave

drain water

None Would reduce

wetland habitat,

reduce fish

flows, raise water temperatures,

increase TDS,

concentrate

pesticides, and

increase channel

velocities in

some areas

users with no

available supply

SOURCE State of California, Water Conservation In California, Department of Water Resources Bulletin No 198 (Sacramento, Calif May 1976), p 70
Ch. VIII Technologies Affecting Surface Water Storage and Delivery . 199

ious sodium salts meet these conditions and a

sodium-treated reservoir will have a lifespan

of many years (1 1). Soil sealants of other types,

such as bentonite clays, have given variable results with differing soil types.

Evaporation Control

INTRODUCTION

The process of evaporation requires a source

of energy to vaporize water and a mechanism

to transfer water vapor from the liquid’s surface to the air, The climate in arid and semiarid

lands provides both factors in abundance, and

evaporation is high. Solar energy drives evaporation while low atmospheric humidity and

frequent high winds accelerate the transfer of

water vapor into the air.

Since conserving collected water is one of

the most economical methods of maintaining

an adequate water supply, a great deal of research has sought effective evaporation control technologies, These technologies increase

water supplies, in effect, by increasing reservo

ir capacity without new construction. They

alter the processes that contribute to evaporation by: 1) lessening the amount of energy that

reaches the water surface to drive evaporation,

and 2) altering the ease with which vaporized

water moves into the air.

Four methods of controlling evaporation

have received attention: 1) surface-area reduction, 2) reflective coatings, 3) surface films, and

4) mechanical covers. Surface-area reduction

can be achieved by selecting proper sites, by

diking to eliminate shallow areas of each reservoir, by deepening existing reservoirs, or by

compartmentalizing them. Deepening reservoirs reduces evaporation both by exposing less

water surface to warm, dry air and by lowering the temperature of the deeper water (and

thus increasing the amount of energy needed

to evaporate that water). “Compartmented”

reservoirs actually consist of several separate

reservoirs of varying depths (fig. 42). Water is

used from the shallower reservoir until the remaining water equals the storage capacity of

the other compartments. water from the first

container is pumped to fill the others at that

Figure 42.— A Compartmented Reservoir

in Operation

Water is used from and pumped between separate reser.

voirs so that the evaporative surface is as small as possible

time, This process is repeated as other reservoirs are drawn down, It ensures that most reservoirs will have the lowest possible ratio of

surface to volume water and thus the lowest

evaporation.

Reflective coatings are designed to reduce

the amount of incident solar radiation reaching

the water. They also may provide a barrier to

vapor. Surface films, which do act as barriers,
200 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

received considerable attention during the

1950’s and 1960’s, Single-molecule films of

long-chain alcohols were applied, sometimes

by airplane. More substantial floating covers

also have been developed. These mechanical

covers include polystyrene sheets, lightweight

concrete slabs, wax blocks, and rubber sheets.

Average evaporation from reservoirs throughout the West is approximately 6 percent. In

some regions, though, reservoir evaporation

may reach about 40 percent of usable storage

(4). Small reservoirs, stock tanks, and farm

ponds with large surface areas exposed to arid

conditions may lose more water to evaporation

than is used productively (26). Compartmented

reservoirs can reduce evaporation substantially (fig. 43), Measurements made under idealized conditions in Arizona suggest that savings

of 35 to 50 percent are possible, but these

amounts vary in different climates (6).

Evaporation reductions achieved using different methods have been variable and often

Figure 43. —Evaporation From

Compartmented Reservoirs

Reservoirs with several compartments have the potential

for reducing evaporation. The amount of water “saved” can

be substantial, as illustrated in this idealized graph for

Tucson, Ariz.

disappointing. For example, reflective coatings

have reduced evaporation by about 50 percent

for 1 month, but the materials used, such as

perlite, eventually become waterlogged. Once

coatings are wetted, evaporation savings drop

to about 10 percent, making such technology

impractical. Reflective coatings and surface

films are unstable if the water surface is not

still. Long-term field studies show that monomolecular layers of alcohols reduce evaporation only about 10 to 20 percent (4,14). These

controls are most economical for large reservoirs or in highly regulated river systems where

evaporation losses are large and increasing salinity levels must be controlled.

Mechanical covers are often simple and costeffective and have the highest potential for use

on small reservoirs, stock tanks, and ponds,

Materials of various kinds have achieved

reductions in evaporation of 80 to 90 percent.

Only minor problems have been reported, such

as damage by birds and weathering (14). Some

elaborate types of covers are specially treated

to retard weathering, but this makes them too

expensive to use for conventional agriculture.

They may be cost-effective when used in conjunction with water-harvesting methods, compartmented reservoirs, or less-than-full irrigation.

Vegetation Management In

and Near Surface Water

Riparian Vegetation

INTRODUCTION

Riparian zones constitute only a small fraction of Western lands. Their scarcity belies

their critical role, however, in affecting and

maintaining watershed stability, water quality, livestock grazing, wildlife habitat, and

recreation (22). These areas also are significant

for agriculture; they provide high-quality forage

and drinking water for livestock and can decrease soil erosion when in good condition.

They may, however, use water intended for irrigated crops, Riparian zones also constitute

an important esthetic and wildlife resource

(table 49). For example, although riparian zones
Ch. VII—Technologies Affecting Surface Water Storage and Delivery . 201

-—

Table 49.—Southwestern Birds That Rely on Wetland and Riparian Habitats

Distribution of bird species among habitats (percent)

Wetlands and/or Riparian Suburban and

Location (no. species) only riparian preferred Nonriparian agricultural

Blue-Point Cottonwoods (58) . . . . . . . . . . . . . . . . . . 45 29 24 2

Salt River Valley (86) . . . . . . . . . . . . . . . . . . . . . . . . . . 44 23 27 6

Central Arizona Mountains (102) . . . . . . . . . . . . . . 7 22 68 3

Flagstaff (125). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 18 62 2

Grand Canyon (122) . . . . . . . . . . . . . . . . . . . . . . . 16 14 68 2

Arizona (242) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 22 46 2

Southwest Lowlands (166) . . . . . . . . . . . . . . . . . . . . 47 26 23 4

SOURCE Adapted from R Roy Johnson, “’The Lower Colorado River,”’ Strategies for Protection and Management of Floodplain Wetlands and Other Riparian Ecosystems

U S Department of Agriculture Forest Service General Technicai Report WO-12 (Washington, D C U S Government Printing Office, 1979), P 43, table 2

represent less than 1 percent of public arid

lands, 75 percent of all sagebrush steppe wildlife in southwest Wyoming depends on these

areas (33,34), and over half of the land designated Arizona State Natural Areas include riparian areas (3).

Riparian zones are identified by characteristic shrubs, trees, and grasses that are associated with abundant water. Plants that tap

ground water, called “phreatophytes, ” are

common (fig. 44 and table 50). Plant species

vary throughout the West as a result of climatic

and management differences. The present vegetation sometimes is dominated by exotic

species, such as saltcedar, which have invaded

wide geographic areas and replaced native cottonwoods, willows, and mesquite.

Assessment

Knowledge of the hydrologic role of riparian

vegetation has changed considerably in the

past 30 years. Therefore, the approach to management also has changed. Early work indicated that phreatophytes “waste tremendous

quantities of ground water each year, ” cover

about 16 million acres in the 17 Western States,

and use as much as 25 million acre-ft of water

annually (32), Such estimates often were based

on limited studies, however, and extrapolation

to the entire West is suspect.

Early workers assumed that most, if not all,

of the water “saved” by removing riparian

vegetation would remain in ground or surface

waters and be available for direct human use.

While some streamside plants use large

amounts of water, removing the plants does not

Figure 44.—Some Riparian Plants, Called

Phreatophytes, Tap Ground Water

necessarily make this water available for other

uses. One of the first long-term measures of water availability before and after clearing was

completed in 1982. These Arizona results indicate that water “savings” depend on the

vegetation that replaces phreatophytes, Annual

average water “losses” are likely to increase

by 60 percent, remain about the same, or decrease by 2 percent if three different irrigated

25-160 0 - 1 4 : QL 3
202 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —— — .

Table 50.—Widespread Phreatophytes of the

Western United States

Common name Scientific name

Baccharis. . . . . . . . . . . . . . . . Baccharis spp.

Rabbitbrush. . . . . . . . . . . . . . Chrysothamnus spp.

Saltgrass . . . . . . . . . . . . . . . . Distichlis spp.

Wildrye. . . . . . . . . . . . . . . . . . Elymus spp.

Velvet ash . . . . . . . . . . . . . . . Fraxinus velutina Torrey

Wirerush . . . . . . . . . . . . . . . . Juncus balticus Willdenow

Sprangletop. . . . . . . . . . . . . . Leptocioa fascicularis

(Lamarck) A. Gray

Alfalfa. . . . . . . . . . . . . . . . . . . Medicago sativa Linnaeus

Reed . . . . . . . . . . . . . . . . . . . . Phragmites communis

Trinius

Engelmann spruce . . . . . . . . Picea engelmanni Parry

Cottonwood, quaking aspen Populus spp.

Mesquite . . . . . . . . . . . . . . . . Prosopis spp.

Willow . . . . . . . . . . . . . . . . . . Salix spp.

Elderberry . . . . . . . . . . . . . . . Sambucus spp.

Big greasewood . . . . . . . . . . Sarcobatus vermiculatus

(Hook) Torrey

Buffalo berry . . . . . . . . . . . . . Shepherdia spp.

Alkali sacaton . . . . . . . . . . . . Sporobolus airoides Terry

Saltwort . . . . . . . . . . . . . . . . . Sueda depressa Watson

Saltcedar . . . . . . . . . . . . . . . . Tamarix spp.

SOURCE T W. Robinson, Phreatophytes, US Geological Survey Water-Supply

Paper 1423 (Washington, D C U.S Government Printing Office, 1958),

pp 32-40, table 1, in part

forage grasses are substituted for saltcedar and

mesquite, Without irrigation, more water probably would remain in ground and surface supplies, but no data verifies this (9).

Vegetation along rivers and canals also traps

sediments, with both positive and negative

results. In areas such as the Pacific Northwest,

where soil erosion is severe, streamside plantings of phreatophytes and other plants supplement older structural control methods. In other

areas, sediment is trapped upstream of reservoirs, extending their useful life. However,

dense growth of phreatophytes can also block

channels (fig. 45), When water flow is constricted, flooding can increase.

There is less emphasis placed on eradication

of phreatophytes now that the results of past

attempts appear questionable and multiple-use

management is more common, In fact, phreatophytes such as mesquite and rubber rabbitbrush are potential new crops in the West (ch.

IX). If they are developed, what is now considered to be a waste of agricultural water

could become a beneficial use.

The technologies used to manage riparian

vegetation are similar to those for brush management (chs. VI and IX) but are often constrained by the need to prevent water pollution.

Chemical control and the use of fire are limited,

and riparian vegetation is often mechanically

cleared as a result. Dropping ground water levels quickly may be a practical method of control if a simultaneous use of the water ensures

that the water table remains below plant roots.

Antitranspirants, nondestructive chemical

methods used to slow water use, have been applied to riparian vegetation. They are costly,

their application is difficult, and their longterm effects on wildlife are unknown (10).

Aquatic Plants

INTRODUCTION

A number of organisms that live in and near

water can affect water conveyances. Beaver

and muskrat dams may block channels, and invertebrates may clog closed irrigation pipes,

but aquatic plants present the greatest problems for irrigators (table 51). Such plants interfere with water movement both mechanically and biologically by slowing the movement

of irrigation water, disrupting control devices,

and causing leaks in canal linings. Some may

lose water to the atmosphere at rates greater

than an open water surface (16).

Technologies for controlling and managing

aquatic plants include preventive, mechanical,

biological, and chemical methods. Preventive

measures are often overlooked, These include:

c encouraging growth of adapted plants compatible with irrigation,

● decreasing sources of seeds and other propagules,

● decreasing supplies of potential plant nutrients, and

● designing an irrigation system for quick establishment of cover plants.

Mechanical controls were common before

the availability of pesticides. Weeds were hand

cut, raked, dredged, or chained. Biological control methods are newer; these include the use

of herbivorous fish, competitive plants, and in-
Ch. VII—Technologies Affecting Surface Water Storage and Delivery ● 203

—

Box O.—Of Beavers and Willows: Restoring Riparian Habitats in Wyoming

Some riparian habitats have suffered from mismanagement. In southwestern Wyoming, for

example, about 83 percent of these communities have been lost. This resulted in decreased forage,

accelerated streambank erosion, lower water quality, declining water tables, and loss of fisheries

habitat.

The Rock Springs District of the Bureau of Land Management is one of the groups attempting

to reverse these conditions. Healthy willows appear to be key to this process. Some riparian areas

have been restored, with the cooperation of ranchers, by 1 to 3 years’ rest from grazing. Forage

production increased by almost 2,000 pounds per acre in one study site where grazing management was tailored to willows.

In other areas, stream conditions require that more complex technology be used. Costs for improving these areas have ranged from $3,000 to $100,000 per site when structural methods were

applied. A newer approach provides building materials at low cost to a different kind of engineer:

beavers. As beavers use wood and old tires to build new dams, water storage increases and streams

stabilize. This sets the stage for riparian recovery as willows and other plants colonize flooded areas.

private companies also have undertaken projects to restore riparian habitats. Timberline Reclamations, Inc., for example, has provided consulting services throughout the Western States, applying both engineering and biological approaches to natural resources. According to the company, the effects sometimes have been large: restoration of a creek in Montana which had been

destroyed by grazing resulted in a substantial increase in property values based solely on the improved fishery.

These technologies appear to be very effective. They are too new, however, to have long-term

records.

SOURCE: Excerpted from: Bruce H. Smith, “Riparian Willow Managament: Its Problems and Potentials Within the Scope of Multiple Use on Public Lands” (Lander,

WyO.: University of Wyoming, Shrub Ecology Workshop, June 5-6, 1990) and “Restoration of Riparian Habitats Within the BLM-Rock Springs District”

(Salt Lake City, Utah: Native Plants, Inc., Wildlife Habitat Rehabilitation and Reclamation Symposium, Jan. 10-11, 1983). Timberline Reclamation, Inc.,

Bozeman, Mont., n.d.

sects and pathogens. Chemical

elude both water and ditchbank

of pesticides.

ASSESSMENT

methods inapplications

Recent estimates indicate that aquatic plants

interfere with irrigation in as many as 60 percent of all canals in the Western United States.

As many as 85,000 miles of canals could be adversely affected. Some water managers believe

that aquatic weed problems are becoming more

severe. Both the introduction and spread of

prolific, nonnative plants and the rapid eutrophication, or nutrient buildup, of surface waters contribute to these changes. These problems have a large economic impact. For example, the Bureau of Reclamation spent about

$6 million annually to control aquatic plants

in its water systems in the late 1970’s (36).

Perhaps the most effective and least costly

approach to aquatic-plant management is prevention. But if part of the prevention system

breaks down, other methods are necessary.

There has been a resurgence of interest in

mechanical methods as stringent restrictions

on herbicides take effect and aquatic plants are

recognized as a renewable resource (27). Mechanical control is especially important when:

1) herbicide residues cannot be tolerated,

2) water conditions preclude isolation of chemicals, 3) nutrient removal is important, 4) largescale biomass removal is required before beginning an integrated-management program, or 5)

biomass has economic value, Mechanical

methods tend to be expensive, time-consuming,

and laborious. If the plants are not removed,

they can clog downstream structures. Mechanical systems are used by several municipalities,
204 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—————— ... —

Figure 45.—Cross Section of Brazes River, Tex., Before and After Saltcedar Invasion

10

1973 bank 1973 bank

15

}

10 10

5 5

0 0

0 15 30 45 60 75 90 105 120 135 150 165

Distance (meters)

SOURCE W H Blackburn R W Knight, and J L Schuster Saltcedar Influence on Sedimentation in the Brazes River Jourrral of SoiI and Walter Conservation

37(5) 301, September/Oclober 1982, fig 3

Table 51 .—Major Aquatic Weeds and Extent of Total U.S. Infestation

Present extent Potential

of infestation infestation

Plants (common/scientific names) (acres) area (acres)

Waterhyacinth Eichornia crassipes (Mart.) Solms. . . . . . . . . . . 1,000,000 9,550,000

Watermilfoil Myriophyllum spp. . . . . . . . . . . . . . . . . . . . . . . . . . . 500,000 17,450,000

Alligatorweed Alternanthera philoxeroides (Mart.) Griseb. . . . 60,000 9,850,000

Hydrilla Hydrilla verticillata (L. f.) Royle . . . . . . . . . . . . . . . . . . . 50,000 4,305,000

Egeria Egeria densa (Planch.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50,000 10,845,000

Waterlettuce Pistia stratiotes L. . . . . . . . . . . . . . . . . . . . . . . . . . 3,000 9,550,000

Waterchestnut Trapa natans L. . . . . . . . . . . . . . . . . . . . . . . . . . . 3,000 1,050,000

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,666,000 62,600,000

SOURCES US Department of Agriculture,“Report of the S E A Research Planning Conference on Aquatic Weed Control”

(Davis, C , Sept 13-15, 1977), 1978, p 50 Edward E. Terrell, A Checklist of Names for 3,000 Vascular Plants of Economic

Importance, Agriculture Handbook No 505 (Washington, D C. U S Government Printing Office, May 1977)
Ch. VII— Technologies Affecting Surface Water Storage and Delivery . 205 —

Photo credit USDA SoiI Conservation Service

Waterhyacinths are important aquatic weeds in

California, other warm parts of the United States, and

many of the world’s reservoirs and rivers

counties, lake owners’ associations, State and

Federal agencies, and private contractors. Despite this history, no focused data base exists

on the potential for marketing products from

weeds (36]. Research at a number of locations

is evaluating harvesting equipment, plant processing, and the use of weeds for compost, biogas production, or animal feed.

Biological methods of pest control are generally effective, economical, and minimally

detrimental to the environment. Insects are being used to control alligatorweed and there are

several promising candidates for controlling

waterhyacinth (21). The grass carp, a fish introduced from China, can control many types

of aquatic plants, but fear persists that it could

become a pest and eliminate native game fish

(30). Different species of spikerush (Eleocharis

spp, ), native aquatic plants, are able to eliminate or reduce populations of aquatic weeds

by a combination of competition for nutrients

——

and space and chemical “interaction s,” or allelopathy (13]. ” Nonetheless, effective biological control, which is both widely available and

acceptable for a large number of different species, is still rare.

Chemical control by herbicides is sometimes

faster and easier than other methods. In some

cases, chemicals can nearly eliminate aquatic

plants and reduce problems of reinfestation.

Some are selective enough to remove only

those plants that are undesirable, providing a

way to alter the habitat for specific purposes.

But some chemical controls have serious drawbacks–e.g,, high cost, toxicity to fish, lack of

specificity, toxicity to crops and livestock-or

other hazards. Recent restrictions on the use

of chemicals, especially in and around water,

has limited the chemical controls available

[table 52), other types of nonpesticidal chemicals such as plant growth regulators or dyes

that darken water and shade plants are promising.

In the case of large bodies of water, single

ownership is rare, and management for multiple uses makes chemical treatments of any kind

difficult. Integrated weed management, which

combines the best of all types of control technologies in a long-term management plan, is

a promising approach under those and other

conditions. However, many of the early mechanical and chemical control technologies were not intended for use in integrated

weed management systems. Therefore, they

are not well adapted for this purpose. New integrated-management schemes are only in early stages of development (29,36),

——

*Allelopathy is the production of (,henll(; al substan(:(:s [)} on(,

species that inhibit the germ i nation, ~rowth, or life of another

species.
206 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

Table 52.— Restrictions on the Use of Aquatic Herbicides

Aquatic weed Herbicide Rate Restrictions

Algae (phytoplankton, filamentous,

Chara) Copper sulfate 2.7 lb/A-ft. Do not use in trout waters

Copper chelates 0.6-1.2 gal/A-ft. Do not use in trout waters

(Cutrine Plus)a

Endothall (Hydrothol 1.1 pts/A-ft. F = 3 days; L, D = 7 days

191)a Do not use for crop irrigation

Simazine (Aquazine) 1-3.4 lb/A-ft. 1, L, D = 12 months

Submersed plants (coontail, watermil- Endothall (Aquathol

foil, pondweeds such as sage, curly- K)a

1.3 gal/A-ft. S = 1 day; F = 3 days; lb, D

leaf, leafy) —— 7 days

Diquat 1-2 gal/SA S, L, I = 10 days;

Simazine (Aquazine) 3.4-6.8 lb/A-ft. 1, L, D = 12 months

Free-floating plants (duckweed, watermeal) Diquat 1 gal/SA S, L, I = 10 days; D = 14

days

Simazine (Aquazine) 3.4-6.8 lb/A-ft. 1, L, D = 12 months

Rooted-floating plants (waterlilies, spatterdock) 2, 4-D (Aquakleen) 200 lb/SA Do not apply to waters for 1,

D, dairy animals

Emersed plants (cattails, perennial

grasses) Dalapon (Dowpon +

wetting agent) 15 lb/SA Restrict spray to plant

foliaqe

KEY F = fishing, I = irrigation, L == livestock, D = domestic use, SA = surface area, A-ft = acre-foot

aThese are liquid formulations which are also available as granules

bTreated water may be used for sprinkling bent grass Immediately

SOURCE Carole A Lembi, “Aquatic Weed Control—In Review, ” Weeds Today 11(3):5, 1980, table 1

Conclusions

Technologies to develop large sources of previously unavailable surface water are limited,

For example, large-scale interbasin transfers

are feasible technologically but constrained by

economic, legal, social, and environmental

considerations, Similarly, conversion of saltwater to freshwater is very expensive and likely

to be limited to municipal and industrial uses.

Neither large-scale interbasin transfers nor current methods of desalination are likely to provide water for agriculture in the near term.

Aging water storage and conveyance facilities require major public and private investments to repair deterioration. This need, combined with economic, physical, social, and environmental factors, makes construction of

new, large-scale storage facilities unlikely.

Smaller projects, including ones on farms and

ranches, continue to be built, often with State

and local government or private financing or

cost-sharing.

The short-term “losses” of water from storage and conveyance facilities by untimely irrigation water delivery, seepage, evaporation,

and interference by plants are large. While a

number of technologies have been proposed to

“save” this water, few are applied widely.

Their application may involve tradeoffs and the

effect on the entire hydrologic cycle is often

unknown.

Technologies for improving the timing of irrigation water delivery generally are promising. A wide variety of methods is being evaluated, but institutional factors may be the biggest factor limiting their adoption. High costs

and low effectiveness limit application of many

seepage and evaporation control technologies,

especially on large lakes and reservoirs. Similar

methods are economical now for use on small

reservoirs or stock ponds. Because the amount

of water transpired by phreatophytes and other

riparian vegetation and the availability for
Ch. VII—Technologies Affecting Surface Water Storage and Delivery ● 207 — . — —

other uses are uncertain, former eradication

measures often have been replaced by multipleuse management of streamside lands. In some

areas, especially the Southwest, where exotic

CHAPTER VU

1!

2.

3.

4.

5.

6

7.

8.

9.

10.

11

Anderson, W., Wyoming State Engineers Office, personal communication, 1981.

Banks, Harvey 0. “Interbasin Transfers, ” OTA

commissioned paper, ApriI 1982.

Bergthold, P. M., “Arizona State Park’s Natural

Area Program, ” Strategies for Protection and

Management of Floodplain Wetlands and Other

Riparian Ecosystems, USDA Forest Service

(“Washington, D. C.: U.S. Government Printing

Office, 1979), pp. 243-247.

Brockway, Charles E., “Supply and Distribution

of Water for Irrigation, ” OTA commissioned

paper, September 1982.

Catalytic, Inc., Desalting Handbook for Planners (Washington, D. C,: U.S. Department of the

Interior, OWRT TT/80 3, 1979].

Cluff, C. B., “Surface Storage for Water-harvesting Agrisystems, ” Rainfall Collection for Agriculture in Arid and Semiarid Regions, G. R.

Dutt, C. F. Hutchinson, and M. Anaya Garduno

(eds.) (Slough, U. K.: Commonwealth Agricultural Bureaux, 1981), pp. 23-30.

Cochrane, W. W., The Development of American Agriculture (Minneapolis, Minn.: University of Minnesota Press, 1979).

Council for Agricultural Science and Technology, “Water Use in Agriculture,” Report No. 95

[Ames, Iowa: CAST, 1982).

Culler, R, C., Hanson, R. L., Myrick, R. M.,

Turner, R. M., and Kipple, F. P., “Evapotranspiration Before and After Clearing Phreatophytes, Gila River Flood Plain, Graham County, Arizona, ” Geological Survey Professional

Paper 655-P, U.S. Department of the Interior

[Washington, D. C.: U.S. Government Printing

Office, 1982).

Davenport, D. C,, Martin, P, E., and Hagan, R.

M., “Evapotranspiration From Riparian Vegetation: Conserving Water by Reducing Saltcedar

Transpiration, ” Journal of Soil and Water Conservation 37(4): 237-239, 1982.

Dutt, G. R., “Establishment of NaC1-Treated

Catchments, ” Rainfall Collection for Agriculture in Arid and Semiarid Regions, G. R. Dutt,

C. F. Hutchinson, and M. Anaya Garduno (eds.)

— — —

plants have rapidly spread, control remains

necessary, but the effect on the overall water

balance is not known. Effective methods are

available for managing aquatic plants,

REFERENCES

12.

13.

14,

15.

16.

17<

18.

19.

20,

21.

22.

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208 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

23,

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26.

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Gary D. Weatherford (cd.) (Boulder, Colo.:

Westview Press, 1982), pp. 23-31.

Morrison, W. R., and Johns, H., “Canal Linings

and Soil Sealants, ” Water Systems Management

Workshop, Session Notes, Session 7-1 (Denver,

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and Power Resources Service, 1980), pp. 1-33.

National Academy of Sciences, More Water for

Arid Lands (Washington, D. C.: NAS, 1974).

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Weeds Useful: Some Perspectives for Developing Countries (Washington, D. C.: NAS, 1976).

North, R. M., and Neely, W., “A Model for

Achieving Consistency for Cost-Sharing in Water Resource Programs, ” Water Resources Bulletin 13(5):995-1005, 1977.

Oliver, F., Hansen, G., Otto, G., and Nibling, F.

L., “Vegetation Management and Pest Control, ”

Water Systems Management Workshop, Session Notes, Sessions 12-1 and 12-2 (Denver,

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Pierce, B. A., “Grass Carp Status in the United

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7(2):151-160, 1983.

Replog]e, J. A., Merriam, ]. L., Swarner, L. R.,

and Phelan, J. T., “Farm Water Delivery Systerns, ” Design and Operation of Farm Irrigation

32.

33.

34

35.

36,

37,

38.

39,

404

Systems, M. E. Jensen (cd.), American Society

of Agricultural Engineers Monograph No. 3

(ASAE), 1980, pp. 317-343.

Robinson, T. W., Phreatophytes, Geological

Survey Water-Supply Paper 1423 (Washington,

D. C.: U.S. Government Printing Office, 1958).

Smith, Bruce H., “Riparian Willow Management: Its Problems and Potentials Within the

Scope of Multiple Use on Public Lands, ” Shrub

Ecology Workshop (Lander, Wyo.: University

of Wyoming, June 5-6, 1980).

Smith, Bruce H, “Restoration of Riparian

Habitats Within the BLM-Rock Springs District, ” Wildlife Habitat Rehabilitation and Reclamation Symposium (Salt Lake City, Utah:

Native Plants, Inc., Jan. 10-11, 1983).

Smith, Felix, U.S. Fish and Wildlife Service,

personal communication, 1982.

U.S. Department of Agriculture, Report of the

SEA Research Planning Conference of Aquatic

Weed Control, Davis, Calif., Sept. 13-15, 1977

(Washington, D. C.: U.S. Government Printing

office: 1978-795-767-385, 1978).

U.S. General Accounting Office, Desalting

Water Probabl~~ Will Not Solve the Nation Water Problems, But Can Help (Washington, D. C.:

CED-79-60, 1979).

U.S. General Accounting Office, Federal

Charges for Irrigation Projects Reviewed Do

Not Cover Costs (Washington, D. C.: PAD-81-07,

1981).

U.S. General Accounting Office, Water Issues

Facing the Nation: An Overview (Washington,

D. C.: GA()/CED-82-83, 1982).

U.S. Interagency Task Force Report, Irrigation

Water Use and Management (Washington, D. C.:

U.S. Government Printing Office, 1979).
Technologies

Affecting Soil Water
—

Contents

Page

The Water Setting: Soil and Water Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Infiltration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Soil-Water Movement and Retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Soil-Water Losses . . . . . . . . . . . . . . . . . . . . . . . . . ........! . 4 . . . . . . . ! . . . . . . . . . . 212

Technologies . . . . . . . . . . . . . . . . . . . . . ! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

Conserving Precipitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

Supplementing Soil-Water Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Supplying Full Water Needs to Plants ...,... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

Limited Use of Supplemental Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .o. .. t . . . . . . . . . . . . . . . . . . . . . 238

Chapter VIII References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

List of Tables

Table No. Page

53. Water Available to Plants per Foot of Soil for Various Soil Textures . . . . . . . . . 213

54. Use of Precipitation: Technology, Application, and Effect on Soil Water . . . . . 215

55. irrigation Methods, 17 Western States, 1981 . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . 231

56. Factors Reducing Onfarm Irrigation Efficiency . . . . . . . . . . . . . . . . . . .......+. 232

List of Figures

Figure No. Page

46. The Role of Soil in the Hydrologic Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

47. Soil particle Size and Infiltration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

48. Diagrammatic Cross-Sections of Three Terrace Types. . . . . . . . . . . . . . . . . . . . . . 218

49. Development of a Saline Seep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

50. Areas of Potential Saline Seep Development, Northern Great Plains Region . . . 223

51. Water Destinations in a Cropped Field.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

52. Effects of Agricultural Water Conservation on Streamflow. . . . . . . . . . . . . . . . . . 230

53. Onfarm Irrigation Efficiencies, 17 Western States . . . . . . . . . . . . . . . . . . . . . . . . . 232

54.Surface-irrigation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

55. Sprinkler Irrigation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

56. Drip Irrigation Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Chapter VIII

Technologies Affecting Soil Water

Agricultural technologies that affect soil water have helped transform the “Great American

Desert” into an area of high annual agricultural

production. This change has occurred largely

because of improved methods of conserving

precipitation and the practice of irrigation.

New technologies and changes in the amount

and location of land to which they are applied

continue to shape Western agriculture and evidence suggests that future changes will be as

extensive as those of the past.

nologies that increase soil-water supplies.

These technologies involve a gradient from

conserved to added water. Some conserve precipitation, others supplement rainfall and

snowfall with limited amounts of applied water, and another group provides enough additional water to fill the crop’s requirements, “Irrigation” usually refers to the last type of technology, the one that uses the largest amount

of applied water,

This chapter first discusses soil and water

relationships, then examines some of the techTHE WATER SETTING: SOIL AND WATER RELATIONSHIPS

Additions of water to soil come from three

sources: precipitation (snow, rain, sleet, or

hail); application of irrigation water; and upward movement of water into the root zone

from a water table (capillary rise). Losses from

the soil occur through evaporation from the soil

surface, transpiration by growing plants, and

deep percolation (fig. 46). Soil plays a key role

i n the hyrdrologic cycle. Its properties help determine how much water runs off the land, the

a moun of water that can be supp1ied to growing plants, and the quantity of water that will

percolate to the ground water.

Infiltration

Infiltration results from the interactions between soil, vegetation, landscape, and weather

(e.g., rainfall intensity and duration), however,

soil properties dominate the process. Coarsetextured soils (“texture” refers to the size of the

soil particles), such as sands, or soils with good

structure (‘structure’ refers to the arrangement of soil particles into aggregates) usually

take in water quickly. Clay soils or those with

a compacted surface layer take in water slowly (fig. 47). Another important determinant of

i n filtration is initial soil-water content. Generally, dry soils absorb water readily; water will

move more slowly into a soil that is wet.

Site conditions also affect infiltration. Where

slopes are steep, water moves rapidly across

the surface with little time for infiltration. Conversely, water will move more slowly across

nearly level areas and these sites generally experience less runoff.

Vegetation can affect infiltration in several

ways. Plants can intercept water before it

reaches the soil surface and thereby reduce the

amount of water available for infiltration.

Vegetation can also facilitate water movement

into soil by slowing its movement across the

surface and allowing more time for infiltration

and by protecting the soil surface from the impact of falling raindrops. Finally, plants and

products of their decomposition can improve

soil structure and thus infiltration.

SoiI-Water Movement and Retention

Soil-water movement is a dynamic process.

Soil water can move downward, upward, and

laterally in response to different physical and

biological conditions. During and after initial

infiltration, for example, water generally moves

211
-- — —.. —

212 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

Figure 46.— The Role of Soil in the

Hydrologic Cycle

Precipitation or applied water Infiltrates the soil surface

and IS used by a growing plant or IS lost through evaporation,

percolation, or surface runoff. Some water is also added to

the soil profile through capillary rise.

Soil crop

evaporation transpiration

SOURCE David C Davenport and Robert M Hagan Agricultural Water Conservation California Water Planning and Policy. E. Engelbert (ed.)

Water Resources Center University of California at Davis 1979

Figure 47. —Soil Particle Size and infiltration

Coarse soil Fine soil

Generally, the larger the soil particle and aggregate size,

the faster the rate of water intake.

SOURCE J Howard Turner and Carl L Anderson, Planning for an Irrigation

System (Athens Ga American Association for Voctional Instructional Materials 1980)

downward and laterally in response to gravity and the “pull” of unwetted or drier soil particles. Water in excess of the soil’s “storage

capacity” will continue to move outward from

the wetted soil.

Water also moves upward into the plant root

zone by the process of capillary rise, which occurs where the water table is near the surface,

or where fine-textured soils are present that

can conduct water upward for considerable

distances. Water movement is usually slow and

except on some irrigated lands and in a few

other areas, soil water derived from capillary

rise does not account for a significant portion

of soil-water supplies.

Soils differ in their ability to retain and redistribute moisture, and many of the factors

that affect infiltration affect water retention

and redistribution. These include: soil texture,

soil structure, organic-matter content, clay

type, depth of wetting and amount of water in

the soil, the presence of impeding soil layers,

and evapotranspiration. Generally, about onehalf the water held in the soil after gravitational

water (water that moves under the force of

gravity and is not retained in the soil) has

drained away can be used by plants. This quantity of water can be stored for a long period

of time for later use by crops (table 53).

Soil-Water Losses

Water that could be used by plants can be

“lost” in several ways. Losses can occur when

water fails to infiltrate the soil and runs off the

surface. After water is stored in the soil, evaporation, transpiration by plants of low economic value (e. g., weeds), and percolation beyond

the plant root zone can reduce soil-water supplies. Evapotranspiration losses are especially critical in the arid and semiarid regions

because water lost in this process cannot be

recovered except through the course of the

hydrologic cycle, Water lost in surface runoff

and deep percolation generally remains a part

of water supplies and can be recovered.

The amount of water lost in each process differs from site to site and changes over time,
— .—

Ch. VIII— Technologies Affecting Soil Water . 213

Box P.—Soil Properties in the Arid and Semiarid Region

Soils are a product of climate, biological activity, topography, and mineral material acting together through time. These factors interact in varying degrees at a particular site and affect certain physical, chemical, and biological properties of soil. Some physical properties, such as texture and structure—i.e., the size of the soil particles and their arrangement into aggregates—are

critical to soil-water relationships. Chemical properties such as nutrient status and acidity are important to plant growth. Biological properties—e.g., the presence of certain micro-organisms—are

important in plant in animal decomposition and the recycling of plant nutrients.

Soil properties in the arid and semiarid region are dominated by climate, although its effect

is modified by the other factors mentioned above. LOW amounts of precipitation, for example, slow

the rate of soil formation. Similarly, with low precipitation and sparse plant growth, soils that form

on residual rock tend to be shallow. Plant root-restricting layers—e.g., caliche (a more or less cemented deposit of calcium carbonate)—may form because there is insufficient water to wash soluble minerals out of the soil.

Arid- and semiarid-climatic conditions are associated with other soil features. First, these soils

are relatively fertile but often have high soluble salt levels that may restrict plant growth. Second,

organic matter levels tend to be low because precipitation is not adequate for production of large

amounts of vegetation. Consequently, soils often lack good structure. Recent research also suggests that soils with low organic matter do not support high microbial populations—e.g., fungi,

bacteria, and algae—which are critical to decomposition of dead plants and animals and to nutrient

recycling. Some essential plant nutrients—e.g., nitrogen and phosphorus—may be lacking because

these elements are products of organic-matter decomposition. Finally, low levels of organic matter are associated with low nutrient-retention capacities.

Arid and semiarid soils are unique in other respects, particularly in their vulnerability to wind

and water erosion, salinity, and compaction. More importantly, if these processes occur, the results

are long lasting and not easily alleviated, given the slow rate of soil formation, low amounts of

precipitation, and limited plant growth. The recently completed OTA assessment of the impacts

of technology on the Nation’s cropland and rangeland productivity (24) discusses these hazards

in more detail.

Table 53.—Water Available to Plants per Foot of Soil

for Various Soil Textures

Textural description Available water (inches)

Coarse textured:

Sands. . . . . . . . . . . . . . . . . . . . 0.4 -0.75

Loamy sands . . . . . . . . . . . . . . . 0.75-1.25

Moderate coarse textures

(sandy loams, fine

loamy sands) . . . . . . . . . . . . . . . 1,25-1.75

Medium textured

(loams, silt loams) . . . . . . . . . . 1,50-2.30

Moderate fine textured

(clay loam, silty or sandy

clay loam) . . . . . . . . . . . . . . . . . . 1.75-2.0

Fine textured (sandy or silty

clay, clay) . . . . . . . . . . . . . . . . . . 1.60-2.50

SOURCE Hayden Ferguson. William Lyle, Charles Fenster, and Charles Wendt

Dryland Agriculture OTA commissioned paper, August 1982

depending on weather, soil, crop, and season

of the year. Generally, these losses can be

ordered as:

Transpiration > Evaporation > Runoff > Percolation.

As an example, where annual precipitation is

scant, as in the arid Southwest, evaporation

represents less than 10 percent of seasonal

evapotranspiration (13). In other areas where

rainfall is more abundant—e. g., the Great

Plains—up to 50 percent of the precipitation

may evaporate (11).

Agricultural practices can improve soil-water

supplies in several ways. They can help to:
214 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

●

●

●

increase the amount of water moving into This chapter considers some of these techthe soil; nologies. Measures that affect plant transpiraincrease the amount of water retained in tion are considered in chapter IX. *

the soil: and

decrease the amount of water lost in sur- *For additional information on land and soil characteristics

face runoff, evaporation, and deep perco- with agriculture see the OTA assessment, Impacts of Technology

on U.S. Cropland and Rangeland Productivity, OTA-F-166,

lation, August 1982.

Box Q.—Soil-Water Measurement

A number of devices are used by researchers and farmers to measure soil-water conditions.

These tools can help determine the amount of water available for plant growth. On irrigated fields,

soil-water measurement can aid in determining water application schedules. It is important to note,

however, that the ability of plants to remove water from soil is primarily related to the force with

which water is held in the soil and not solely to soil-water content.

One of the oldest methods for measuring soil-water content is by gravimetric determination.

In this process, soil samples are removed from desired depths and placed in cans to prevent moisture

loss. Th samples are weighed, heated to boil away the water, and weighed again. Water content

is calculated as a percentage of dry weight and converted to a volume basis (e.g., inches per foot

of soil) if bulk density of the soil is known (mass per unit volume of an oven-dried soil).

Using electrical-resistance gypsum blocks is a second means of estimating soil water. In this

method, two electrodes are embedded in gypsum blocks and placed in the soil. An electrical current is passed through the electrodes and the resistance across the electrodes is measured. Resistance

across the electrodes increases as the water content of the soil decreases. A calibration curve is

used to determine the soil-water content.

A third device for measuring soil water is a tensiometer. Tensiometers measure the “force

of attraction” of the soil for water and are calibrated to determine soil-water content in each soil.

These tools vary in form. One type, a vacuum-gage tensiometer consists of a porous, fired clay

cup which is attached to a vacuum gage by a water-filled pipe. If the cup is buried in dry soil—i.e.,

where the water has less energy than the water in the cup water will move from the cup into the

soil. When the system comes to equilibrium, the vacuum gage measures the potential as a tension*

in the water. It indicates that plants must work against this tension to extract water from the soil.

Wetting the soil releases the tension and water will move from the soil into the porous cup of the

tensiometer.

The neutron probe is another tool used to measure soil-water content. The components of

the system include a neutron source, a detector, an amplifier, and a scaler. The neutron source

is placed in the soil at a desired depth and emitted neutrons strike hydrogen nuclei that are

associated with water molecules. The scaler then senses the number of hydrogen nuclei and

estimates water content of the soil.

● “Tension” is the pressure required to extract water from soil and indicates the tenacity with which water is held in the soilt.

TECHNOL0GIES

Soil-water supplies in the arid and semiarid evolved. Over large areas of the West, where

region come mainly from two sources—precip- soil-water supplies are derived from precipitaitation and irrigation. Under each set of con- tion, dryland farming or rangeland agriculture

ditions, a distinct type of agriculture has is practiced. Where soil water is provided by
supplemental water applications, irrigated agriculture is practiced.

The technologies described in this chapter

are organized according to the type of agriculture for which they are most likely to be used.

Where dryland farming or rangeland agriculture is practiced, methods that conserve precipitation are appropriate. On irrigated land,

methods that manage supplemental water are

applicable. Although each technology is discussed separately, effective use of precipitation

or irrigation water often requires the use of

more than one technology and skillful management of plants and soil.

Selection of technologies presented here was

based on evaluations of a technology’s ability

to sustain agricultural productivity and potential use across broad geographic areas and in

different types of agriculture. Although each

technology will affect soil-water conditions to

some extent, an estimate of the amount of water that could be conserved by adopting a particular practice is not presented. Reliable estimates are nearly impossible given the broad climatic, topographic, crop, and soil differences

throughout the West, combined with uncertainty regarding the possible extent of application.

Conserving Precipitation

Technologies that conserve precipitation are

aimed primarily at reducing water losses

through surface runoff and evaporation (table

54). These goals can be achieved in three main

ways.

Ch. VIII—Technologies Affecting Soil Water . 215

— —

First, the soil surface can be shaped to

hold water on the surface and facilitate’ water

movement into the soil, Second, soil cover consisting of either growing plants or their residues can be managed to reduce runoff and

evaporation losses. Third, soil properties such

as structure or micro-organism content can be

manipulated to conserve soil water. These

practices also can be used together.

Shaping Soil Surfaces

INTRODUCTION

One of the most important features of a soil

is its ability to take in water. For many centuries, farmers achieved improvements in infiltration by altering the soil surface or by

reshaping the land. The ancient Egyptians

plowed their fields to lift and loosen the top

layers of soil to allow more water to infiltrate.

Ancient people also used terraces, embankments built across a slope, to hold precipitation

on the land.

In modern agriculture, the purposes and

types of practices used to alter and reshape the

land surface are similar to those used in the

past. Today, however, many modifications

have been made in the types of tools used and

in the degree to which soil and vegetative cover

are disturbed. For example, plowing, which is

one step in seedbed preparation, has been replaced in many farming operations by minimum tillage, which leaves crop residues on the

soil surface. Another practice, pitting, is apTable 54.—Use of Precipitation: Technology, Application, and Effect on Soil Water

Application

Technology Range Dryland Irrigated Comments

Mechanical land treatments . . . . . . . . . x x x Slow surface runoff, increased infiltration, –

facilitated water movement through soil

Terraces . . . . . . . . . . . . . . . . . . . . . . . . x x x Slow surface runoff, increased infiltration

Land grading or leveling . . . . . . . . . . . . . — x x Slow surface runoff, increased infiltration

Mulches ., . . . . . . . . . . . . . . . . . . . x x x Slow surface runoff, increased infiltration,

slow evaporation

Plant-barrier systems . . . . . . . . . . — x x Slow evaporation conserves snow.

Modification of plant canopies. . — x x Slow evaporation

Mychorrizal fungi . . . . . . . . . . . . . . . . . x x x Enhances plant-water uptake

Harvester ants and termites . . . . . . . x — — Increased infiltration

Soil conditioners. . . . . . . . . . . . . . . . . — x x Increased water retention

SOURCE Office of Technology Assessment, 1982
216 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands ——. ———

plied on rangelands. It uses a mechanical device to form small, shallow basins in the soil

surface to hold precipitation onsite. In contrast,

deep plowing, a practice used on croplands,

completely inverts and mixes the soil layers to

improve infiltration and water movement

through the soil.

ASSESSMENT

Many land-shaping practices are effective in

increasing the amount of water retained onsite

for plant growth. In addition, these technologies

can help conserve soil by reducing surface runoff. Generally, management requirements are

low, and practices can be applied to rangeland,

dryland, or irrigated areas.

The application of some practices is limited,

however, by physical considerations. First,

many technologies are site-specific; the waterconserving ability of each practice varies with

soil type, topography, vegetation, and weather.

Under natural rainfall conditions in arid areas,

for example, these technologies will have little effect in improving soil-water conditions,

A second limitation is the relatively short lifespan of some technologies. Some tillage practices (e.g., basin tillage) must be applied each

time a crop is planted. Similarly, the storage

capacity of pits diminishes rapidly, and pits

may disappear within 6 to 10 years depending

on site conditions. Finally, excessive working

of the soil, coupled with the use of heavy machinery needed for application of some practices, can alter soil structure, thereby aggravating the soil conditions that these operations are

trying to improve.

The application of land-shaping practices

may be limited also by economic considerations, For some ranchers and farmers, the expense associated with applying these technologies (i. e., special equipment, labor, fuel, land

taken out of production) may outweigh their

benefits in increased forage or crop production. Furthermore, economic evaluations of

costs and benefits that could assist farmers and

ranchers in planning their operations are often

not available.

Land-shaping practices may not be applied

to grazing lands for other reasons, Often these

—.— ———

lands are too arid, or on soils too shallow or

too infertile, to realize an increase in forage

production with their use. On more productive

areas, some ranchers may object to mechanical

treatments of natural grasslands because these

practices have not been applied traditionally.

Finally, on public rangelands,

who has a grazing permit may

from applying these practices.

Mechanical Land Treatments

Mechanical land treatments

an individual

be prohibited

include such

operations as deep plowing or ripping, land imprinting, contour furrowing, basin tillage, and

pitting, In general, these practices alter the soil

Photo credit USDA-Agricultural Research Service

The land imprinter can help establish grass on nearbarren areas. The imprinter presses furrows and

seedbeds of varying depths on the soil. The patterns

direct runoff rainwater and concentrate it where

new grass is seeded.
structure and attempt to increase the amount

of water retained onsite. Their application can

aid plant establishment and can increase existing plant production.

Many mechanical land treatments are effective in conserving water and are used presently. Contour furrowing, for example, has been

applied on rangelands in the Great Plains and

Interior Basin and has been especially useful

on sodium-affected soils to improve infiltration, reduce the sodium hazard, and increase

herbage production. Contour furrows have an

additional benefit in that they can catch more

snow than can nearby unfurrowed areas.

Another treatment, basin tillage, has been used

in row-crop production in the southern Great

plains and has helped increase the amount of

water stored in the soil. Deep ripping or plowing has been used on rangeland, dryland, and

irrigated areas to break up compacted subsurface layers and to mix the different soil textures. Ranchers and farmers have reported inCh. VIII— Technologies Affecting Soil Water . 217

creased forage and crop yields after this operation.

Extensive applications of mechanical land

treatments are somewhat hindered by the sitespecific nature of each technology, For example, some research indicates that pits are ineffective in areas of low precipitation and on clay

soils (23 ,33). Where pits are used on range in

poor condition, weed problems may develop,

Ripping treatments on six Western range sites

decreased perennial grass production, and researchers concluded that, in these areas, the

relativel y minor soil surface modifications did

not have a marked effect on runoff or water

retention (6).

Mechanical land treatments tend to have a

limited lifespan. The storage capacity of pits

and contour furrows diminishes rapidly with

time, and basin tillage requires application

each time a crop is grown. Where deep plowing is practiced, large soil pores and channels

Photo credit USDA Soil Conservation Service

Contour furrows are generally constructed to hold water onsite until it infiltrates the soIl

25-160 0 - 1 5 : QL 3
218 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands ——. —

are difficult to maintain with subsequent tillage

operations.

Finally, the application of these practices

tends to be energy- and capital-intensive, Generally, special equipment is needed that maybe

too expensive for some operators. Equipment

design also limits application of some practices. For example, basin tillage is limited currently to row-crop (e. g., corn, soybeans, and

cotton) production, although it could be applied

to close-growing, small-grains (e.g., wheat and

barley) production if planting equipment were

modified.

Terraces

Terraces are earthen embankments, channels, or combinations of embankments and

channels built across the slope of the land (fig.

48). By reducing the length of a slope, terraces

help conserve precipitation and irrigation

Figure 48. —Diagrammatic Cross-Sections of

Three Terrace Types

Terraces have been used for centuries and several types

exist. The ridge terrace (A) is constructed on the contour to

retain water on the land. Conservation bench terraces (B) are

constructed to spread runoff across a level cropped area. Level

bench terraces (C) retain water that falls on level cropped

areas.

A Ridge terrace

Original ground

---- -

Contributing

area

Level bench

———-.— — . .

water by reducing surface runoff. In addition,

terraces trap snow and increase over-winter

water storage. In semiarid regions, terraces

have been used traditionally in dryland agriculture. Irrigators may also use terraces to

reduce their irrigation water requirements.

Besides controlling runoff, terraces have

other benefits. They help reduce soil erosion

and sediment content in runoff water, improve

formability of sloping lands, and reduce peak

runoff rates to installations downstream.

Several problems limit the use of terraces,

however. One major difficulty is that terrace

design has not kept pace with changes in farm

machinery and maneuverability of farm equipment is sometimes difficult. A second problem

is that construction generally entails the removal of topsoil from large areas and the use

of heavy equipment. These two factors may

combine to cause surface compaction and may

result in reduced crop and forage production.

Initially, construction may interfere with seasonal agricultural operations and uneven drying, pending, and severe erosion in different

parts of the same terrace channel are also common in the first 3 to 5 years after construction.

Finally, during wet years, weed and insect control may be difficult,

Economic considerations may pose a barrier

to the adoption of terrace systems, Terraces are

often costly, although some technical and financial assistance may be available to producers

for design and construction. Maintenance requirements are high, and labor and energy

costs may increase more on terraced fields than

on nonterraced areas. In addition, some land

is lost from crop production because of the terraces.

Land Grading or Leveling

Land grading or leveling is a technology that

consists of smoothing a field’s surface to make

it level, A leveled field allows more uniform

water distribution, eliminates dry or waterlogged spots, and slows runoff. Currently, the

practice is applied most often to irrigated fields

but can be used on dry-farmed lands.
Although land leveling is effective for many

areas, the technology is not suited to some

fields. When first applied, leveling may reduce

infiltration and accelerate soil erosion because

the vegetative cover is disturbed and soil aggregates are destroyed. Second, some soils have a

thin topsoil, and extensive leveling operations

expose generally less productive subsoil. On

these soils, to maintain productivity, topsoil

may have to be set aside and spread back onto

the site after the grading is completed. Finally, leveling operations may fill in low depressions, some of which are important to wildlife,

Application of land leveling is affected by a

number of economic considerations, as well.

Government agencies and irrigation districts

may have technical and cost-share provisions

for land leveling on irrigated land that can reduce water costs, increase crop yields, and improve farm profits. For most dryland crops,

however, the benefits derived from land leveling do not pay for its application. Laser leveling is particularly expensive at present, * Basic

laser equipment costs from $12,000 to $20,000,

and scrapers that can be laser controlled range

in cost from $9,000 to $30,000 (17).

Managing Soil Cover

INTRODUCTION

Agricultural practices often have dramatic

effects on the ground cover and consequently

on soil and water relationships. This relationship has been long recognized by agriculturalists. In semiarid regions of the West, for example, early proponents of fallow systems (a

type of dryland farming in which, generally,

a crop is harvested every 2 years) believed that

a covering of soil, or “dust mulch, ” left on the

surface in alternate years would prevent water

from evaporating from the surface. Although

these claims were valid to some extent, wind

tended to blow away the mulch and the amount

of water conserved was negligible.

*rI”radit ]onal lan(l-surveying techniques that determine th(’ extent of leveling ncedwl, hat’e been replaced i n some areas by

laser-[; ontrollwl cfekfl(.es that permit more ~)recise le~’cling and

prokide for more uniform distribution of ~tater.

Ch. VIII—Technologies Affecting Soil Water ● 219

Technologies that affect soil cover aim to reduce surface runoff, increase infiltration, and

reduce soil erosion. These practices include

plant-residue management, application of materials that act like plant residues, and manipulation of growing vegetation (see box R).

ASSESSMENT

Managing soil cover is an effective means to

increase the efficiency of precipitation storage,

but several limitations to their use exist. First,

management requirements are high. With improved soil-water conditions, weeds and other

crop pests may build up and require control

by mechanical or chemical means. Second, soil

covers may lower soil temperatures and reduce

seed germination, a consideration in cooler

regions. Third, these practices are largely

limited to dryland and irrigated regions because of the economics of their application and

maintenance.

Mulches

Surface mulches are protective soil coverings

that are spread or left on the soil surface and

used to increase infiltration, decrease surface

runoff and erosion, and slow evaporation

losses. * They can be used in irrigated, dryland,

and rangeland agriculture, and consist of crop

residues applied where they are produced or

of introduced layers of plant materials, gravel,

black plastic, or sewage sludge.

Residual Mulches.—The use of crop residues as surface mulch became a common practice during the 1930’s to reduce the effects of

wind and water erosion. Since then, farming

practices and equipment have been developed

to till the soil and plant crops without inverting or burying the residue. On rangeland, slash

or debris from brush and trees are used as

mulch.

The value of mulch for collecting and storing available precipitation in dryland agriculture has been documented by numerous inves-

*Depending on the am~~n~ of crop residue a (’ailable, some

nontranspiring vegetation, such as standing wheat stubble, ca n

reduce evaporation losses. Howe\’er, if plant residues are scant,

as in many arid and semiarid areas, the reduction in e\’apora -

tion is minimal.
220 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

.— .

Box R.—Conservation Tillage: A New Way to Farm?

Prior to the 1940’s, farmers relied on a variety of tillage practices to prepare a seedbed, control

weeds, and bury plant residues. With the advent of chemical herbicides, many producers began

to substitute chemical weed control and “conservation tillage” for some of the traditional tillage

operations.

Although conservation tillage has attracted much attention in recent years, the practice is quite

old. In 1814, James Hall of Virginia secured a patent for a method of planting corn in an unplowed

field. He marked the land in squares; each square was a certain dimension and distance from other

plots and contained a given number of corn plants. Only these squares were cultivated, manured,

and mulched; the rest of the field remained in grass. Hall had little success with his idea.- The corn

was unable to withstand dry weather, and many farmers criticized the practice as slovenly.

The term “conservation tillage” is inexact in meaning. Generally, the practice uses fewer operations to produce crops than does conventional tillage. Three other characteristics distinguish conservation tillage: it uses implements other than the moldboard plow; it leaves residues on the soil

surface; and, it depends primarily on herbicides for weed control, although the degree of dependence

on herbicides varies.

In the arid and semiarid region, conservation tillage is important, especially for its use in conserving water and soil. Small-grain producers can find its application particularly beneficial, and

the advent of large chisel-type air seeders that can plant large acreages in a short period of time

has made conservation tillage profitable for these farmers. Conservation tillage has lower farm

labor and preharvest fuel requirements than does conventional tillage. It can be used on sloping

lands and can enable some producers to plant more than one crop in a season (multiple-cropping)

or omit the fallow period (continuous cropping).

These advantages are countered by several physical and economic constraints that include

high management requirements needed for control of weeds and other pests and for fertilizer placement, high costs of herbicides, adverse effects of herbicide use on human health and the environment, limited application in some cool dryland regions and some irrigated areas, high costs of

seeding equipment, and availability of plant varieties that will germinate in thick residue.

SOURCE: William T. Dishman, advisory panel member, personal communication. 1983; Hayden Ferguson, William Lyle, Charles Fenster, and Charles Wendt,

Dryland Agriculture, OTA commissioned paper, July 1982; Impacts of Technology on U.S. Cropland and Rangeland Productivity (Washington, D. C.:

U.S. Congress, Office of Technology Assessment, OTA-F-166, 1982); Andrew C. Revkin, “Paraquat-A Potent Weed Killer is Killing People,” Science

Digest 91:36-38, 42, 100-104, 1983.

tigators (11). Mulch reduces runoff and tends

to increase soil-water storage by protecting the

soil surface from the impact of precipitation

and by allowing more time for infiltration to

occur. In colder regions, standing stubble

mulch traps snow. Additional benefits include

higher crop yields, increased soil organicmatter content, more stable soil aggregates, and

decreased wind and water erosion.

Mulches are used widely in dryland crop

production but less extensively on rangeland

and irrigated fields. On rangeland, a lack of

plant residues restricts application to critical

areas—e.g., surface-mined sites or saline-affected soils (34). On irrigated land, mulches are

used most often under sprinkler irrigation systems. Farmers who attempt to use mulches in

surface irrigation may experience difficulty in

getting supplemental water through a field (13).

Crop residues also are difficult to maintain

because relatively low amounts are produced

in most dryland areas and a large portion is

destroyed during tillage operations. For example, stubble-mulch tillage, a method of cultivation practiced widely in small-grain production, attempts to maintain surface residues

through each tillage operation. However, this

practice destroys approximately 15 percent of
Photo credit: U.S.DA. Soil Conservation Service

A no-till drill, designed by the University of Idaho, used

on an Idaho farm. No-till is one form of conservation

tiIlage to reduce soil erosion and soil-water loss

(see Box R)

Ch. VIII—Technologies Affecting Soil Water ● 221

the residue each time; over a fallow period,

stubble-mulch tillage will destroy about 75 percent of the original residue (11).

Weeds and insect pests may build up when

crop-residue mulches are used. In addition, in

cooler dryland regions—e.g., the northern

Great Plains and the Pacific Northwest-crop

yields are sometimes lower under a residue

mulch than would be expected, considering the

amount of water available. Cool soil temperatures during critical stages of crop growth or

reduced levels of nitrates during certain periods of the year are possible reasons for yield

reductions.

Another limitation to the use of crop-residue

mulches to conserve available water is the increased risk of development of saline seeps (fig,

49). This is a hazard especially in the northern

Photo credit: USDA Soil Conservation Service

Minimum till planting in corn stubble, Gage County, Nebr. (see box R)
222 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— . —.— —

Figure 49. - Development of a Saline Seep

Saline seeps form when soil water percolates downward beneath the root zone, picks up soluble salts in the soil, and

accumulates on shallow, less permeable soil layers. A perched water table forms, and lateral flow then moves saline water

from recharge to discharge areas, where it evaporates and leaves a salt deposit on the soil surface. These areas, often

identifiable by a white salt crust on the soil surface, tend to reduce or eliminate crop and grass production, and the consumption of salts may result in animal kills.
Ch. Vlll—Technologies Affecting Soil Water ● 223

Great Plains (Montana, North and South Dakota), where a wheat-fallow rotation is followed, because of the geology and climate of

the region (fig. 50). Black, et al. (5), estimate that

2 million acres (approximately 800,000 hectares) of land used for dryland agriculture have

been affected by saline seeps. (Ch. XI discusses

flexible cropping, a possible way to reduce this

hazard.)

Introduced Plant Residues and Artificial

Materials. —Introduced materials used for

mulching have comparable purposes as residue mulches. Materials vary; straw (grain

stalks after threshing) and wood chips, sewage

sludge, gravel mulches, and black plastic have

been used,

Introduced mulches are used in both rangeland and dryland farming regions with success.

Mulches have been especially useful on rangeland to help in reseeding and plant establishment efforts. In dryland regions, Choriki

(8) showed that layers of “pea” gravel about 2

inches deep on the soil surface increased the

storage efficiency of summer precipitation

by some 60 percent and made annual cropping

feasible in the low rainfall area.

The major limitations of introduced mulches

are similar to those associated with residual

Figure 50.— Areas of Potential Saline Seep

Development, Northern Great Plains Region

Alberta

Saskatchewan

I \ I

Area of potential saline seep

development

mulches—e.g., cooler soil temperatures that

may inhibit seed germination and accelerate

plant pest buildup. In addition, introduced

mulches are sometimes difficult and expensive

to acquire, transport, apply, and maintain. The

ability to reverse the effects of an introduced

mulch, especially gravel or sewage sludge, has

been questioned (24).

Plant-Barrier Systems

Growing plants can be used to conserve soil

and water that might otherwise be lost because

of the drying effects of wind. The types of

plants used as barriers vary; historically, rows

of trees and shrubs (shelterbelts) have been

used, More recently, research has focused on

incorporating single and double rows of’ relatively low-growing vegetation (e.g., wheatgrass,

sorghum, or corn) within a field to catch Snow,

reduce windspeed near the soil surface, reduce

evaporation from wet soil, and control wind

erosion.

Plant-barrier systems are used mainly in

semiarid dryland farming areas that rely on

snow to supply soil water. The barriers are especially useful in conserving snow during the

second winter of a fallow period. The subsequent increase in soil water can boost crop production and may be sufficient to permit annual

cropping.

Limited research indicates that plant barriers

can also be applied to rangeland. Grass strips

planted between low-growing sagebrush vegetation increased onsite snow retention and contributed to increased soil water and improved

site productivity (30).

Plant barriers also have other benefits. Tree

barriers provide protection from wind erosion

and are pleasing esthetically. Annual vegetative

barriers and shelterbelts also can provide cover

and food for wildlife.

Although plant barriers are an effective way

to conserve snowfall, several considerations

may restrict their adoption. First, it is sometimes

physically difficult to get water into frozen soil

once the snow begins to melt. In the northern

part of the Great Plains, for example, soils

freeze deep and “hard.” Moreover, these soils
224 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Photo credit: USDA-Soil Conservation Service

This farmstead windbreak includes a variety of plants, both trees and shrubs. Besides conserving snowfall, the

windbreaks protect against wind erosion, provide wildlife with food and cover, and are estheticalIy pleasing

Photo credit: USDA-Soil Conservation Service

Tall wheatgrass barriers control wind erosion and trap snow to increase stored soil water. Tall wheatgrass barriers

reach an average height of 4 ft and snow accumulates relatively uniformly across the interval between barriers
Ch. Vlll—Technologies Affecting Soil Water . 225

-.

are often wet when they freeze. As a result,

storage efficiency of thesoil is often low and

serious erosion and water loss problems can

occur. Occasional midwinter warm periods

have a similar effect, In these areas, tillage

operations may be needed to roughen the soil

surface to trap snow and snowmelt water and

to allow water movement into the frozen soil.

Other constraints on adoption of plantbarrier systems include:

accelerated wind erosion if plants are not

spaced properly;

buildup of crop pests—e.g., weeds and

insects—and difficulty in control;

loss of some cropland;

disease problems in some areas, especially in northern Washington and southeastern Idaho, where snow mold can develop and affect winter wheat;

soil-water use by noncrop plants;

uneven grain ripening (especially where

annual barriers are planted) unless barriers

are spaced properly to ensure uniform

snow distribution; and

soil compaction where annual barriers

force tillage operations in the same direction and on the same path.

Modification of Plant Canopies

To reduce the amount of evaporation that

occurs early in the growing season, two approaches have been developed to allow for

earlier canopy closure: increased plant density and modified plant spacing. These measures

are especially effective in reducing evaporation

losses in areas of frequent rainfall early in the

growing season or of frequent irrigations that

are required because of soil texture and depth.

Modifications in plant canopies can also reduce wind velocities near the soil surface and

lessen evaporation losses. Such practices can

result in a slight increase in yield because of

the higher plant populations.

Widespread application of these systems is

hindered by two considerations. First, under

high water-stress situations, close-growing

crops may suffer yield reductions. Second, if

tall and short varieties are combined in a field

to reduce wind velocity, height difference may

become insignificant when plants are waterstressed (10).

Changing Soil Properties

INTRODUCTION

Besides mineral and organic constituents,

soils include a living component that consists

of a diverse population of micro-organisms

such as bacteria, fungi, algae, and protozoa;

small invertebrate animals such as earthworms, ants, and termites; larger vertebrate animals like snakes, moles, gophers; and birds,

such as burrowing owls. This diversity in animal and plant life accounts for the varied role

the living component plays in soil and plant

processes. For example, some micro-organisms

cause plant disease. More importantly, however, they decompose dead plants and animals,

recycle plant nutrients, and play a critical part

in forming the humus that binds minute soil

particles into larger aggregates. Humus aids in

water infiltration and retention and plant-root

development. Soil animals may also assist in

improving water relationships by mixing the

soil profile and by breaking up hard subsurface

layers.

Amendments* added to soil can affect soil

and water relationships. For example, chemical

fertilizers appear to stimulate plant root growth

and aid soil-water extraction. Chemical soil

conditioner materials (other than conventional

fertilizers) that are added to soils to change

them physically, chemically, or biologically,

imitate the action of living organisms and increase the amount of water retained in soils.

Plastic sheeting or gravel can be buried within

sandy soils to assist in retaining water for plant

growth.

ASSESSMENT

The potential for changing soil properties to

improve soil-water retention by using biologi-

—

“Substances that aid plant growth indirectly by improving the

condition of the soil.
226 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—

cal organisms or other amendments is unclear

and more research is needed. These technologies seem to have some application on small

areas with special problems, but, generally,

questions about their longevity, effectiveness

under different climates and variable field conditions, economics of use, and other possible

effects have not been resolved.

Mycorrhizae

Mycorrhizal fungi are beneficial soil microorganisms that form symbiotic associations

with the fine feeder roots of plants, By colonizing the plant root, the fungi receive an energy

source, nutrients, and other plant chemicals

from the host, Generally, the plant benefits

from improved uptake of mineral nutrients

(particularly phosphorus) and water. Ninetyeight percent of all plant species form mycorrhizal associations and most require symbiosis

for maximum growth and survival (12).

Mycorrhizal fungi may play an important

part in agricultural production in arid and

semiarid regions. Research shows that plants

colonized by these fungi seem more tolerant

of dry conditions, have increased resistance to

the toxic effects of salts, and have improved

tolerance to numerous root pathogens (e.g., 14,

19,27). Also, mycorrhizae have been shown to

improve the growth and survival of plants introduced into arid and semiarid lands by 20 to

200 percent (e.g., 1,7). The mechanisms that underlie these effects are not understood fully.

Improved mineral nutrition of the host is

thought to be a dominant influence, but osmotic and hormonal adjustments to infection may

also be involved.

Potentially, two important applications of

mycorrhizal inocula exist. The first involves

rebuilding depleted populations of mycorrhizal

fungi in soils that have been disturbed by soil

erosion, surface mining, fire, fumigation, or

long-term cropping with nonmycorrhizal species. Plants grown on such soils are frequently stunted and may benefit from mycorrhizal

inoculations, The second application is associated with transplanted horticultural crops.

Mycorrhizal inoculation can reduce transplant

injury and increase growth and establishment

of some nursery crops (4,21).

Despite their potential utility, commercialization and use of mycorrhizal inoculants are

limited at present. Major obstacles include

problems in development of commercial culture systems for inoculum production, risks

associated with inocula that may carry disease,

lack of efficient field inoculation techniques,

lack of guidelines for predicting costs and

benefits of inoculations, and the need for identification of superior and versatile fungal

strains.

Harvester Ants and Termites

Western harvester ants and termites are regarded as pests of economic importance on

many Western range sites. They frequently denude an area of existing vegetation through

forage and mound activities.

Limited research indicates that dry matter

yields in the area around ant colonies and termite mounds are much higher than in adjacent

areas (3,28). Researchers speculate that vegetation removal by the ants and termites increases

soil water in the mound area and its border.

In addition, ant and termite activity may be

beneficial to the physical and chemical character of the soil and may increase infiltration and

soil-water storage.

The potential for this technology is unknown.

Most range managers view these insects more

as a detriment than a benefit to rangeland,

Their future use appears restricted to small,

local sites.

Soil Conditioners

Soil conditioners, also known as soil amendments and soil additives, are materials other

than conventional fertilizers that are added to

soils to change them physically, chemically, or

biologically to improve productivity. In the arid

and semiarid regions, most attention has focused on the use of these substances to increase

the amount of water retained in soils that have

low water-retention capacities.

Some chemical amendments, such as waterholding starch copolymers (“super-slurpers,”

H-SPAN) have shown a tendency to increase

water retention in sandy soils, Naturally occur-
ring zeolite minerals have also been used to increase soil water-holding capacity.

Widespread use of chemical conditioners has

been hampered by many scientific, economic,

and legal considerations. Generally, research

is lacking on their application. Zeolites have

not attracted widespread attention from agricultural researchers in the United States. Use

of expensive soil conditioners is limited to

special soil conditions and to high-value crops.

Finally, because of unfavorable experience

with chemical soil conditioners in the past,

some States have taken legal action to require

scientifically acceptable evidence for efficacy

Box S.-Irrigation

Ch. Vlll—Technologies Affecting Soil Water ● 227

before these products are offered for sale within the State.

Supplementing Soil-Water Supplies

The primary purpose of irrigation is to supply water to crops during periods of water

shortage, The practice lessens some seasonal

risks associated with farming, allows production in areas that could not produce most crops

otherwise, and gives producers greater flexibility in selecting crops to be grown. Also, irrigation can boost crop yields.

Irrigated agriculture plays a significant role

in modifying natural resources. Some of these

and Soil Erosion

Many people assume that soil erosion in the arid and semiarid region is limited to overgrazed

rangeland and dryland agriculture. Irrigated lands are considered to be free of this hazard. For

example, the Soil Conservation Service’s (SCS) 1977 National Resources Inventory estimated that

erosion on irrigated row crops averaged approximately 3 tons/acre/yr. The national average on

all cropland was about 7 tons/acre/yr. (Soil conservationists generally recommend that soil losses

not exceed 5 tons/acre/yr.)

Some irrigated lands do have little erosion. For example, surface irrigation in an enclosed basin

(basin irrigation) usually results in no net soil loss to the fie1d and minimal soil transfer within

the basin. Often, however, erosion in other types of surface systems and on sloping lands are much

higher. A study by SCS in Idaho (Hazleton Butte Watershed) found that on fields with slopes of

O to 4 percent and under furrow irrigation, erosion averaged 8 tons/acre/yr. Winter erosion added

another 15 tons/acre/yr.

One of the reasons that soil erosion on irrigated land has been discounted is that it is hard

to measure. Erosion depends on soil, slope, climate, and agricultural management, including the

type and management of the irrigation system (e.g., length of run, set time, and number of sets

in a field). Furthermore, within a single field, soil loss can vary from irrigation to irrigation. For

example, early season irrigations can be more erosive than later irrigations because the furrows

are unstable and susceptible to the erosive force of water. Another factor that makes erosion difficult to measure is that under some types of irrigation, the process of soil erosion is fundamentally different from the process that occurs under rainfall. Because of these discrepancies, the usual

method of estimating soil erosion on cropland (Universal Soil Loss Equation) is not accurate on

irrigated lands.

A number of practices can be adopted to reduce erosion on irrigated land, and some erosion

control methods are also water-conserving operations. Conversion from furrow irrigation to

sprinkler irrigation, installation of sediment traps, or simpler operation such as planting a filter

strip of grain across the top or bottom of a furrow-irrigated field, or reducing the amount of water

running through the furrow once it has been wetted, can cut erosion lossses. If weeds can be controlled, conservation tillage on irrigated lands is another possible option. If soil savings can be

combined with improved profitability—higher crop yields or lower operating costs--farmers will

be more likely to adopt these practices.

SOURCE: Excerpted from: Neil Sampson, “Soil Erosion and Irrigation,” paper prepared for the American Farmland Trust Study on Soil Conservation Issues,

Mar. I, 1983,
228 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

effects—depleted water supplies, altered

streamflow conditions, and degraded water

quality—have been discussed in other chapters.

A major problem affecting irrigated soils is

salinity, although soil erosion and nutrient content of irrigated crops are concerns as well

(e.g., 22,26).

Soil salinity is often associated with irrigated

agriculture although nonirrigated lands can

also be affected. * Salinity is a special hazard

in the Western States; van Schilfgaarde (32) estimates that 25 to 35 percent of the irrigated

cropland in the region is affected by high levels

of salinity and that the problem is growing.

Furthermore, the costs of damage to both farmers and municipal and industrial users are

enormous. The Bureau of Reclamation, for example, has estimated that the annual cost of

damage in the Colorado River Basin is $100

million and will escalate to $237 million per

year in 2000 (in constant 1981 dollars) (2). The

process of salinization is considered in this section because excessive salt concentrations can

interfere with plant-water uptake. Under these

conditions, a plant can show signs of water

stress even though the soil is wet and crop

yields can be lowered.

Soil salinization can occur in two ways—either insufficient irrigation water is applied or

drainage is inadequate. In the first case, as irrigation proceeds and water (containing salt)

is added to the soil, pure water evaporates or

is transpired by plants, and salts remain in the

soil. Soil weathering, accelerated by irrigation,

also contributes salts to the soil solution. Unless

these salts are periodically flushed by rain or

by excess application of irrigation water, the

salt content of the soil will gradually increase

and soil salinization will occur. In the second

case, where drainage is inadequate, salinization occurs as repeated irrigations raise the

ground water table and capillary rise carries

water close to the soil surface where it evaporates, leaving a salt residue.

—

*In salinization, a soil accumulates sufficient soluble salts to

impair its productivity. These salts mostly consist of various proportions of the cations (positively charged ions) sodium, calcium,

and magnesium, and the anions (negatively charged ions)

chloride and sulfate.

Leaching, whether by periodic flushing or

adequate irrigation, can mitigate the effects of

salinization, However, large water applications

require adequate drainage (sometimes a network of drains must be installed across a saltaffect area) and often increases the salt concentrations for downstream users. If smaller quantities of water are used for leaching, a crop’s

tolerance to increased salinity in the lower part

of the root zone must be considered and monitoring is necessary. As stressed by Rhoades

(25):

At present we do not have suitable inventories of soil salinity in this country nor do we

have operational monitoring programs to follow the salinity status in our soils . . . The prop-
—— .-——— —. —

er operation of a viable, permanent irrigation

agriculture that is also efficient in water use

requires periodic information on the salinity

levels and distributions present within the rootzones of the soils of irrigation projects. Only

then can the adequacy, effectiveness, and efficiency of the projects’ operations be validly

assessed with respect to salt balance.

Other management methods to cope with soil

salinity include precise land leveling of fields

to enable flood, rather than furrow, irrigation

so that infiltration is more uniform and dissolved salts are transported below the root to

the drainage system with a minimum of applied water. Where land leveling is impractical,

sprinkler irrigation may be needed. In both

cases, irrigation must be scheduled with smaller quantities of water at each irrigation and at

more frequent intervals to maintain downward

movement of salts and favorable growing conditions for the plant, especially during germination and seedling stages.

Onfarm salinity management is costly and

many farmers may not have the capital necessary for such practices. One estimate placed

the cost for a sprinkler irrigation setup at about

$500 per acre. Precision land leveling was estimated at $50 to $100 per acre [15).

Defining Irrigation Terms

Farmers are encouraged often to “save” irrigation water, but this term and its effects on

the individual and on total water supplies are

sometimes unclear. First, this section defines

some of the terms associated with irrigation

water management and then discusses how onfarm water conservation affects an individual

irrigator and regional water supplies.

Technologies that affect irrigation practices

are often discussed in terms of their “onfarm

irrigation efficiency, ” defined as the ratio, or

percentage, of the volume of water stored in

the soil root zone and used by the crop to the

volume of water delivered t. the farm (31). Onfarm irrigation efficiency characterizes the onfarm distribution system and the field-application system.

Ch. VIII— Technologies Affecting Soil Water . 229

—

After irrigation water is applied, water that

does not become a part of soil moisture supplies in one field (this component includes

seepage, surface runoff, and deep percolation)

remains part of an area’s total water supply and

is usually available for reuse downstream,

although pumping may be required and water

quality may be changed significantly. These

losses are termed “recoverable.” Losses that

result from evaporation from open water, and

from the soil surface, transpiration, and flows

to saline sinks are called “irrecoverable” since

they are lost except through the course of the

hydrologic cycle or costly desalination operations (fig. 51).

Surface runoff and deep percolation can be

curtailed in several ways, resulting in higher

onfarm irrigation efficiencies. In most cases,

however, a roughly equal reduction in return

flows occurs, and a small net water savings is

realized (fig. 52) (9).

Figure 51 .—Water Destinations in a Cropped Field

ES T EW

Key

Recoverable losses. Irrecoverable losses:

S—Seepage EW-Evaporation from open water

L—Leakage ES-Evaporation from soil

SP-Operational spills T—Transportation

RO-Surface runoff

DP-Deep percolation
230 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 52.— Effects of Agricultural Water

Conservation on Streamflow

These illustrations show in a simplified way, the interrelations among water supply, gross demand, and return flows.

In figure A, 100 units of water are diverted from a 1,000-unit

supply of streamflow. 50 of the 100 units are lost as evapotranspiration (resulting in an onfarm irrigation efficiency of

500/0). 50 units are returned to the water source as return flow,

thereby yielding a final streamflow of 950 units.

In figure B, the farming area has improved its irrigation

efficiency to 830/0. Still meeting crop needs for water of 50

units, only 60 units of water (instead of 100 units) need to be

diverted. Streamflow is reduced to 940 units between points

of diversion and outflow and 10 units are returned to the

source. Final streamflow remains at 950 units.

c.

In figure C, the evapotranspiration requirements of the

agricultural area are reduced from 50 units to 40 units.

Because ET is smaller, less water diversion is needed (50

units instead of 60 units). The smaller diversion results in a

streamflow of 950 units between the points of diversion and

return flow; final streamflow is 960 units (instead of the 950

units in the other examples).

(ET = Evapotransplratlon IAE = Irrlgatton Appllcatlon Efflclency)

SOURCE David C Davenport and Robert M Hagen, Agricultural Wafer Conservation in California, With Emphasis on the San Joaquin Valley,

technical report, Department of Land, Air and Water Resources,

University of California, Davis, 1982

Reduction in irrecoverable losses are generally harder to achieve but can result in a reduction in net water consumption. Evaporation

losses, for example, can be reduced most easily by preventing unnecessary wetting and exposure of the soil surface. In many areas, the

effort required to reduce evaporation is not

worthwhile in relation to the amount of water

saved. Furthermore, a reduction in evaporation

losses can increase temperatures and reduce

humidities at the surface and result in greater

transpiration losses. Crop transpiration losses

are especially difficult to control. Producers

can decrease crop acreage and thereby curtail

total transpiration losses, grow crops that mature in a shorter time, or use antitranspirants

but these measures are usually not economically feasible for most producers.

To assess the effect of irrigation water conservation on total water supplies, a study by

the Soil Conservation Service looked at several

irrigation water conservation measures, both

on and off the farm, and evaluated their potential for reducing irrigation water demands in

the 17 Western States (31). With no increase

in either irrigated acreage or volume of water

provided to water-short areas, improved irrigation efficiencies reduced irrigation diversions

by over 30 million acre-ft. However, the water

that was available for reallocation was estimated at only 3.3 million acre-ft.

Other than saving some quantity of water,

onfarm water conservation efforts have both

benefits and negative consequences for an individual and for a wider area. Advantages of

reducing recoverable losses include energy savings by reduced pumping requirements, plantnutrient savings by reducing leaching losses,

less nutrient pollution and salt emission to surface and ground water, fewer plant disease and

weed problems, less standing water from runoff where mosquitoes could breed, and increased instream flows in sections of rivers

where water diversions are reduced. The disadvantage of reducing recoverable water losses

is that less water is available for leaching salts

from the soil, ground water recharge, and wildlife habitat.

Advantages for reducing irrecoverable losses

include reduced draft requirements for both
Ch. VIII— Technologies Affecting Soil Water ● 231

surface and ground water, energy savings from

lowered pumping requirements, increased

streamflow, additional water for other agricultural and municipal and industrial uses, and

improved quality of subsurface water. Reduced

crop yields and the physical requirements

needed to implement measures to reduce evapotranspiration losses are major disadvantages.

Finally, physical, social, legal, and economic

factors often hinder adoption of practices that

could improve onfarm irrigation efficiencies.

These include:

onfarm physical conditions that cannot be

alleviated easily (e. g., sandy soils that have

low retention capacities);

difficulties in identifying practices that

reduce irrigation efficiencies because of

current measurement techniques and services;

relative insignificance of water losses to

an individual if water is inexpensive or

cannot be used if saved;

questions over costs of practices relative

to benefits derived from application;

feasibility of integrating new practices into

existing farm management practices; and

legal uncertainties regarding whether the

farmer can use the water “saved” (see

ch. V).

The following sections discuss various modifications to existing irrigation systems and

possible irrigation strategies that individuals

can use to “stretch” their water supplies.

Supplying Full Water Needs to Plants

INTRODUCTION

Traditionally, irrigation systems are designed

and operated to supply full water needs to

plants so that yields are not limited by water

shortages and yields are maximized per unit

area irrigated. The crop root zone, the depth

of soil where crop roots are actively growing

(usually 1.5 to 6 ft deep), provides a reservoir

for storing water until it is needed for plant

growth. Water that infiltrates the soil but exceeds its storage capacity will percolate below

the roots and will enter the ground water.

ASSESSMENT

In irrigated areas of the West, three major

types of irrigation systems are used to apply

water. The most widespread type is gravity or

surface flow, followed by sprinkler irrigation,

and drip or microirrigation (table 55). A fourth

type, subsurface irrigation, is used less frequently, Each system is best suited to specific

soil, topography, crop, climatic, and economic

conditions. For example, surface methods are

generally the least expensive type of irrigation,

in capital required for application, but they require larger flow rates to operate efficiently

than do sprinkler or drip methods. If less efficient, surface methods require larger gross applications of water than do sprinkler or drip

irrigation. Sprinkler methods are well suited

to steep or rolling lands but often require substantial investments in equipment. Drip irrigation is appropriate for orchard and horticultural crops but less suited to row crops like

corn or cotton. It also requires large capital

investments,

Technically, most irrigation systems have

similar field application efficiencies. However,

actual application efficiencies vary considerably and range from less than 40 percent in

areas where management and site conditions

Table 55.—irrigation Methods, 17 Western States, 1981

Type of irrigation

(in percent)

State Surface Sprinkler Drip

Arizona . . . . . . . . . . . . 93,6 6.0 0.4

California . . . . . . . . . . 77,0 20.0 4.0

Colorado . . . . . . . . . . 78.0 22.0 —

Idaho . . . . . . . . . . . . . . 73.0 27.0 —

Kansas . . . . . . . . . . . . 63.0 37.0 —

Montana . . . . . . . . . . . 92.0 8.0 —

Nebraska . . . . . . . . . . 57,0 43.0 —

Nevada . . . . . . . . . . . . 95.0 5.0 —

New Mexico . . . . . . . 87.9 12,0 0.1

North Dakota. . . . . . . 23.0 77.0 —

Oklahoma. . . . . . . . . . 48.9 51.0 0.1

Oregon . . . . . . . . . . . . 46.9 53.0 0.1

South Dakota . . . . . . 13.0 87.0 —

Texas . . . . . . . . . . . . 72.7 27.0 0.3

Utah . . . . . . . . . . . . . . 77,9 22.0 0.1

Washington . . . . . . . . 28,8 71.0 0.2

Wyoming . . . . . . . . . . 90.0 10.0 —

SOURCE” Marvin Jensen, Overview-Irrigation in U S Arid and Semiarid Lands,

OTA commissioned paper, 1982 (Original source Irrigation Journal,

December 1981)
232 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

are poor to over 80 percent in a well-managed

system under good field conditions (fig. 53).

Reasons for low onfarm irrigation efficiencies

are outlined in table 56.

Surface Irrigation

Surface irrigation refers to irrigation methods where the soil surface serves both as the

channel to distribute the water over the field

and the control for water entry (fig. 54). Gravity

provides the energy needed to distribute the

water. Surface irrigation may be further subdivided into: 1) flooding, and 2) furrow irrigation.

Numerous modifications to existing surface

irrigation operations can be made by irrigators

to reduce evaporation and deep percolation

losses and runoff. These include:

● manipulation of the length of time water

is applied (set time), irrigation stream size,

Figure 53.—Onfarm Irrigation Efficiencies,

17 Western States

SOURCE. U S Department of Agriculture, Soil and Water Resources Conservation Act, 1980 Appraisal, pt. II, 1981

Table 56.—Factors Reducing Onfarm

Irrigation Efficiency

1. Delivery system:

Inadequate water-measurement devices

Unlined ditches

Improper location or alinement of ditches

Obsolete systems

Inflexible delivery schedule

2. Field application system:

Improper land shaping

Improper relationships of slopes, length of run,

border widths, discharge rates

Improper design of sprinkler or drip system

(pumping capacity, pressure, nozzle sizes)

Method of application not suited to soils or slopes

3. Ineffective water management:

Improper timing of irrigations

Incorrect application amounts

Improper scheduling of water

Excessive use of inexpensive water to save labor

cost

SOURCE: U.S. Interagency Task Force, Irrigation Water use and Management,

USDI, USDA, EPA (Washington, D. C.: U.S. Government Printing Office,

1979),

●

●

●

irrigation frequency, and the distance over

which water is applied (length of run);

land smoothing or leveling; ditch lining;

surge flow (a method of water application);

automation; and

system replacement.

In recent years, several developments have

occurred that may further improve onfarm

efficiency of surface systems. Mathematical

models have been developed to simulate and

predict interactions between soil, water, and

crops during irrigation (18). These models may

help decrease the random nature of surface irrigation design and operation and allow for

more effective and timely water application.

At present, models require further refinement

before they are used widely because of the extensive variability in site conditions across the

arid and semiarid region (e.g., soild infiltration

rates, weather, and crop consideration).

Another important modification to surface

irrigation has been use of a tailwater-reuse

system, which consists of a reservoir at the

lower side of a field to collect excess irrigation

water. A pump then delivers recovered water

back to a field. Tailwater-reuse systems allow

application of large quantities of irrigation

water (with accompanying runoff), reduce de-
Ch. VIII—Technologies Affecting Soil Water ● 233

Figure 54.—Surface-Irrigation System

Head ditch Turn outs Measuring

higher than the

field to be

irrigated or

pump and pipeline

SOURCE J Howard Turner and Carl L Anderson Planning for an Irrigation System (Athens, Ga American Association for vocational lnstructional Materials 1980).

Photo credit: USDA-Soil Conservation Service

Potatoes grow in furrow irrigation rows

mand for energy because pumping lift is less

from a tailwater reservoir than from deep

wells, and prevent damage to adjacent property

by irrigation tailwater. However, irrigators

who use a tailwater system lose land from crop

production, and water that has been pumped

through the system two or more times is lower

in quality than the first time through the field.

Laser-controlled land leveling has increased

the size of fields that can be irrigated using

basin irrigation (a type of system consisting of

a level area enclosed by earthen border ridges),

Where soils are uniform, the combination of

large flows with precision leveling can boost

application efficiencies. Expansion of level

basin irrigation over extensive areas of the

25- 160 0 - 16 : QL 3
234 ● Water-Related Technologies for Sustainable Agriculture

West is limited, however, by the availability of

high-volume, instantaneous water flows and by

potential problems with surface drainage in

areas with substantial rainfall. The disadvantages associated with land leveling are a problem also.

Sprinkler Irrigation

Sprinkler irrigation is the application of

water to the soil surface in the form of a spray,

somewhat as rain. Many different types of

sprinkler systems exist; in the United States,

center-pivot systems represent the major

sprinkler irrigation method (fig. 55).

With proper design and under correct

management, sprinkler irrigation systems have

a minimal amount of deep percolation and

runoff loss. The primary practices available to

an irrigator to minimize these losses further are

design changes or changes in operating procedures. For example, sprinkler spacings,

operating pressures, and set times may be

changed, or additional use of automated equipment to control the system may be employed.

Energy conservation has received considerable attention in recent years and poses

a special problem in continuously moving

systems (center-pivot or lateral move). Reducing pressure while saving energy tends to lower

irrigation efficiency because more water is applied and more runoff occurs. Modified-tillage

practices, for example, basin tillage, can be incorporated into the farming program to reduce

these runoff losses. Another practice is the

placement of water application devices below

the crop canopy. Low-energy precision application systems apply water directly to the

irrigation furrow at low pressure through drop

tubes as the sprinkler continuously moves

through the field. Thus, runoff and spray

evaporation are minimized (20).

Drip Irrigation

Drip, or microirrigation, is the frequent, slow

application of water to the soil near the roots

of a plant in sufficient amounts to meet its

needs (fig. 56). The technology was introduced in the Western United States in the early

1970’s; since then, its use has expanded to apin U.S. Arid and Semiarid Lands

proximately 494,000 acres in 1980 (16). Drip irrigation is used primarily on high-value crops

such as avocados, citrus fruits, strawberries,

tomatoes, vineyards, and deciduous orchards,

but has also been adapted to other types of crop

production. Among the advantages of its use

are:

●

●

●

●

●

●

●

●

enhanced water control;

lower seedling mortality;

greater uniformity of plants, bushes, or

trees;

fuel savings;

increased flexibility in the use of fertilizers;

fewer weed problems;

overall yield increases; and

erosion control.

In theory, drip irrigation can increase irrigation efficiencies by reducing evaporation and

deep percolation losses because a small amount

of water is applied to a small portion of the soil

surface. Actual water savings with a drip irrigation system, when compared to conventional

surface or sprinkler irrigation, depends on such

factors as irrigation frequency and crop. * In

irrigation of row crops or crops with a nearly

full cover, the water savings from reduced

evaporation may be less. Drip irrigation with

micro sprinklers * * may increase evaporation

losses when compared with conventional drip

systems because more of the surface is wetted.

Although the high irrigation efficiency associated with drip irrigation makes its use attractive, drip irrigation has some physical and economic limitations. Beyond the wetted zone, soil

salinity may increase. Also, in most systems

only a small portion of the soil is wet and plant

roots tend to be confined to this area. If water

delivery is stopped suddenly, severe plant

stress can occur quickly. Large capital investments are required for plastic pipe, filtration

*The most favorable situation occurs with orchard crops in

early growth stages where large areas of the surface is exposed

and water is not needed in areas not yet explored by roots.

* *Microsprinklers are smaller than conventional sprinkler

heads but larger than standard drip emitters. Their use helps

alleviate clogging hazards associated with emitters and have been

tested in orchards to apply greater amounts of water than would

be possible under conventional drip irrigation.
Ch. VIII—Technologies Affecting Soil Water . 235

—

Figure 55.—Sprinkler Irrigation System

Self-propelled II Hand- or tractor-moved

T Tripod-mounted

%?. . 3

r. J- L - -, --, I

SOURCE” J. Howard Turner and Carl L Anderson, Planning for an Irrigation System (Athens, Ga. American Association for Vocational Instructional Materials, 1980)

equipment, and installation. Energy is required

to pump water through the system, offsetting

some of the energy savings compared to other

irrigation systems. High maintenance is required. Water lines may be damaged by wildlife, insects, or soil-dwelling animals. Lines

must be flushed periodically, and emitters may

clog because of chemical buildup, silt, sludge,

algae, slime, or roots. Emitters must be inspected frequently, and breakdowns in the system are sometimes not seen, especially where

buried drip lines are used.

Photo credit USDA-Soil Conservation Service

In a test field in California, private researchers are

experimenting with the use of drip irrigation

on furrowed cotton

Subsurface Irrigation

Subsurface irrigation is accomplished by artificially raising the water table close to the soil
236 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 56.— Drip Irrigation Systems

Drip irrigation systems usually consist of a network of smalldiameter plastic tubing along each row or between pairs of

crop rows. Water is discharged through uniformly spaced

small openings in the tubing or through emitters, nozzle-like

devices that regulate water flow from lateral lines into the soil.

Filtration equipment, provisions for fertilizer and pesticide injection, a fertilizer holding tank, and hardware to regulate water pressure are usually included as part of the system.

SOURCE J HoW ard Turner and Carl L Anderson Planning for an Irrigation

System (Athens Ga American Association for Vocational Instructional

Materials 1980)

surface. Water reaches the plant roots through

capillary movement upward.

The advantages of subsurface irrigation include reduced evaporation, erosion control,

and fuel and fertilizer savings. This method of

irrigation also allows cultivation and other surface operations to be carried on without concern for the irrigation period.

Certain physical conditions must be met to

ensure the success of subsurface irrigation, and

these limit its application. First, soils should

permit rapid lateral and downward movement

of water yet should be capable of lifting the

moisture from the water table throughout a major portion of the root zone. Second, the topography of the land should be smooth, uniform,

and approximately parallel to the water table

to allow for even irrigation. Third, salinity control is necessary and often requires the use of

auxiliary irrigation systems (surface or sprinkler) to leach salt that accumulates at the soil

surface as water evaporates. Auxiliary irrigations may also be needed for seed germination

and plant establishment.

Limited Use of Supplemental Water

INTRODUCTION

In recent years, in areas where water supplies have become scarce or where the price

of water has increased, two concepts of irrigation management, distinct from full irrigation,

have evolved. “Supplemental” irrigation manages precipitation and irrigation water together

to supply full-crop water needs. In “deficit” irrigation, applied water or applied water combined with precipitation is less than the amount

of water needed for maximum crop yield.

For limited irrigation to succeed, a management strategy is necessary that integrates crop

selection, soil manipulation, and irrigation system management with available water and economic conditions. This plan is flexible and

varies from year to year.

Crop Considerations

Limited irrigation normally requires a diversified cropping program. This program includes:

relatively drought-resistant crops;

deep-rooted crops or crops with dense

root systems that can tap soil water or enhance infiltration;

crop rotations to ensure that water is available during growth periods that are sensitive to water stress; and

in areas of summer precipitation, cropping patterns that provide for a fallow period when rainfall can be stored.
Ch. VIII— Technologies Affecting Soil Water . 237

-.

Soil-Water Considerations

Tillage practices, water-storage facilities (e.g.,

tanks and ponds), and soil-water monitoring

are key elements in limited irrigation. As discussed earlier in this chapter, many land-forming techniques can be used to improve infiltration and ensure that precipitation and irrigation water are retained onsite.

Auxiliary water-storage facilities can also be

used to capture runoff for later use. Water can

be pumped from the storage facility when

crops need to be irrigated or when the soil can

retain the water.

Another aspect of soil-water management is

monitoring the extent of soil-water deficit. This

practice can help a grower identify when irrigation is required.

Irrigation System Management

Effective limited irrigation requires that recoverable losses (e. g., deep percolation and

runoff) are minimized and that water is available to the crop during critical growth periods.

Recoverable water losses can be reduced by increasing onfarm distribution and application

efficiencies (see previous discussion under full

irrigation).

Application methods, suited to the irrigation

system, can also be manipulated to distribute

limited water over a greater land area. For surface irrigation systems, for example, these

methods could include alternate furrow irrigation, which tends to reduce deep percolation

and results in greater lateral movement of applied water in the soil, and alternate furrow irrigation plus basin tillage. This latter practice

allows rainfall to be captured while irrigation

is proceeding. With both sprinkler and surface

methods, irrigators could practice skip-row

planting which leaves a number of rows fallow

to serve as a reservoir for soil water.

A second management practice for use in

deficit irrigation is a limited irrigation-dryland

system. In this system, a field is divided into

three water-management sections, The upper

half of the field is managed as fully irrigated.

The next one-fourth is managed as a “tailwater

runoff” section that uses runoff from the fully

irrigated section. The lower one-fourth is managed as a dryland section. This system has been

tested in the semiarid Texas High Plains region; limited research indicates that it has high

irrigation water-use efficiency when compared

to conventional irrigation (29).

Finally, the timing of irrigation water application is important. This requires that a knowledge of a crop’s most sensitive growth period,

If critical growth periods are known, irrigation

water can be applied at that time to as large

an area as possible, The irrigation is then terminated when plant-water stress on remaining

unirrigated areas reaches a critical point and

when the probable economic response to additional applied water would be mininal for the

area already irrigated. A second irrigation

begins on the area first irrigated and is normally continued until the economic contribution

from irrigation declines or the crop reaches

maturity (2).

ASSESSMENT

Limited irrigation has wide geographic

potential. It could be applied in those irrigated

areas where rainfall can supplement irrigation

water or where drought-resistant crops are

available, Currently, most limited irrigation is

practiced in the southern Great Plains where

high costs for pumping irrigation water are encouraging many farmers to shift from full irrigation to dryland farming. For these individuals, limited irrigation is one way to maintain

higher crop production than possible with dryland farming while minimizing irrigation costs.

Economic and institutional considerations

currently restrict extensive applications of

limited irrigation to areas that face severe

water shortages, Management requirements

are high, and crop yields may decline when

compared to a fully irrigated situation. Limited

irrigation also requires precise and timely application of water; least expensive irrigation

methods (e.g., surface irrigation) are often not

suitable. The availability of large irrigation

flows may limit the use of surface irrigation.

Computerized instrumentation may be needed
238 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

-. -— —

to monitor soil and crop and weather conditions and to control irrigation equipment, Institutionally, because this is a relatively recent

development in irrigation-system management,

many irrigation-system designers and extension personnel may not be able to provide appropriate information to producers who wish

to change to a limited system.

Application of deficit irrigation is limited

also by several technical considerations, First,

standard procedures presently used to predict

seasonal crop-water requirements and critical,

water-sensitive growth periods (water production functions) are not accurate for more than

one geographic area or crop, thus, results cannot be extrapolated across broad geographic

areas or even from one field to another. Second, unless actual evapotranspiration and predicted evapotranspiration deficits are monitored closely and precisely, it is difficult for a

producer to plan irrigation applications during water-stress periods. Monitoring programs

are costly, however, and beyond the means of

many individuals.

CONCLUSIONS

Many opportunities for improving soil-moisture conditions exist, both where precipitation

is used to supply crop-water needs and where

irrigation is practiced. Some of these technologies have been adopted by producers, but

numerous barriers remain to their widespread

application. First, many of these practices are

effective under certain soil and/or climatic conditions. Where site conditions are not appropriate, application can yield little or no improvement in soil-water conditions. Second,

some practices require large economic investments for equipment, fuel, and labor; application costs may outweigh their benefits in terms

of higher farm or ranch profits. Third, the use

of some technologies is hindered by Federal

and State institutions, For example, mechanical land treatments on public rangelands by individuals are often prohibited; water saved by

irrigators is often not available again for their

use. Finally, some practices are difficult to incorporate into existing farm and ranch operations and may require new equipment or skills.

1.

2.

CHAPTER VIII

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Armstrong, W. L,, statement before the Water

and Power Subcommittee of the Ener~vU.1

 and

The extent of soil-water increase that can be

expected with the adoption of a particular technology is difficult to quantify, given the wide

variability in site conditions across the arid and

semiarid region, For technologies that are used

on irrigated land, data that assess the effects

of widespread adoption on total water supplies

are lacking. Similarly, information on economic and social consequences of adoption is generally not available.

Finally, soil salinization on irrigated lands

and its associated effects on other natural

resources may result in a reappraisal of the potential for dryland and rangeland agriculture

in the Western United States. If a shift to limited irrigation or

ture does occur,

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tion.

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Study on Soil Conservation Issues, Mar. 1,

1983,

Schoenbeck, F. “Effect of Endotrophic Mycorrhiza on Disease Resistance of Higher Plant s,”

Z. pflanzenkr. Pflanzenschutz. 85:191-196,

1978.

Sneva, Forest A., “The Western Harvester

Ants: Their Density and Hill Size in Relation

to Herbaceous Productivity and Big Sagebrush

Cover,” J. Range Manage. 32:46-47, 1979.

Stewart, B. A., Duse, D. A., and Musick, J, T.,

“A Management System for the Conjunctive
240 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

30.

31

Use of Rainfall and Limited Irrigation of 32

Graded Furrows,” Sod Sci. Soc. Am. J. 43:407-

411, 1981.

Sturges, D. L., and Tabler, R. D., “Manage- 33,

ment of Blowing Snow on Sagebrush

Rangelands, ” J. Soil and Water Cons.

36:287-292, 1981.

U.S. Interagency Task Force, Irrigation Water 34.

Use and Management, USDI, USDA, EPA

(Washington, D. C.: U.S. Government Printing

Office, 1979).

.

van Schilfgaarde, J., Director, U.S. Salinity

Laboratory, Riverside, Calif., personal communication, 1981.

Vaux, H. J., Wright, J. R., and White, L. M., “Interseeding and Pitting on a Sandy Range Site

in Eastern Montana, ” J. Range Manage, 27:

206-210, 1974.

Wood, M. K., and Buckhouse, J. C., “Technologies for Capturing and Detaining Water on

Rangeland, ” OTA commissioned paper, 1982,
Technologies

Affecting Water-Use Efficiency of

Plants and Animals
Page

The Water Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

Plant Water-Use Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

Animal Water Use . . . . . . . . . .......0, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

The Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + . . . . . . . . . . . . . 246

Methods of Improving Plants and Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

Innovative Applications of the Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..9...-.. 267

Chapter IX References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...9 .. s....... . . . 267

Appendix 9-l.–Scientific Names of Potential ’’New’’ Agricultural Plants . . . . . . . . 269

List of Tables

Table No. Page

57. Comparison of the Total Amount of Biomass Produced per Total Amount

of Water Used in Transpiration for Crop Plants. . . . . 0 . . . . . . . . . . . . . . . . . . . . . 244

58. Comparative Water Use of Animals . . . . . . . . . ....+.... . . . . . . . 4 . . . . . . . . . . . 246

59. Percent of the United States With Soils

Subject to Environmental Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

60. Proportion of Crop Dry Matter Produced That is a Harvestable Product. . . . . . 253

61. Information on Potential New Crops for Arid and Semiarid Lands . . . . . . . . . . 258

62. Results of ’’New” Crop Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

63. The Protein Content and Quality of Various Grains. . . . . . . . . . . . . . . . . . . . . . . . 261

64. Starch and Moisture Content of Several Sources of Starch. . . . . . . . . . . . . . . . . . 262

65. Buffalo Sales in 1981 .1...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

66. A Comparison of Cattle, Sheep and Rabbit Production

on Western Rangelands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....6.... 264

67. Salt Tolerance of Crops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265

68. Halophytes With Potential for Agricultural Use . . . . . . . . . . . . . . . . + . . . . . . . . . . 266

List of Figures

Figure No. Page

57. Working With Protoplasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

58. The Technique of Recombinant DNA Technology . . . . . . . . . . . . . . . . . . . . . . . . . 248

59. A Generalized Method for Developing Drought-Resistant

and Drought-Susceptible Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . 252

60. The Complex Production, Marketing, and Consumption Scheme For

a New Crop Entering the Commercial Market. This Diagram Illustrates

a Potential Strategy for Jojoba Producers and Processors . . . . . . . . . . . . . . . . . . . 260

61. Two Methods for Producing Salt-Tolerant Organisms . . . . . . . . . . . . . . . . . . . . . . 265
Chapter IX

Technologies Affecting Water-Use

Efficiency of Plants and Animals

In the past, agricultural scientists and producers in the United States often chose agricultural technologies for their contribution to

high productivity. Essentially, these practices

made the natural environment less hostile for

plants and animals, a change from depending

on native organisms that were closely adapted

to sometimes harsh conditions. Today, as natural resources become more limited and economic costs increase, biological technologies

that use existing natural resources more efficiently are needed. In the arid and semiarid

areas of the West, these practices would be

water-sparing and would use the special features of the region.

This chapter focuses on technologies that

“stretch” the amount of plant or animal produced per unit of water used. As such, these

technologies are well-suited to the arid/semiarid region. The emphasis here is on working

within the natural limits of arid and semiarid

lands with sophisticated technologies to provide an array of opportunities for sustainable

agriculture.

Regardless of the quantity of water available

for irrigation agriculture, it is likely that these

technologies will figure more prominently in

the region’s future. If the amount of water

available for Western irrigation is maintained,

these technologies can add diversity to agricultural production in the region. If, however, expectations of less irrigation water are realized,

these technologies may be vital in easing the

transition to more suitable production systems.

In dryland and rangeland agriculture, where

production is usually limited by water, these

practices can help sustain some current styles

of production.

Water—the principal ingredient in living tissue—plays a vital role in biochemical reactions,

maintains cell rigidity, moves materials within

plants and animals, and helps to heat and cool

them. Water continuously flows through most

organisms and a certain quantity is an absolute

necessity. When plants open pores (stomata)

in their leaves to take in carbon dioxide for

photosynthesis, water is lost by transpiration,

a process significant because it is both essential and considerable. Desert plants may consume 100 times their weight in water each day

even though they physiologically require only

about 10 percent of that amount. While some

plants are able to slow transpiration, it cannot

be stopped completely without also stopping

all plant growth.

Because of the large amounts of water they

use, plants are a major component of the hydrologic cycle, and technologies have been

developed to make hydrologic changes by modifying vegetation (see chs. VI, VII, and XI).

Because animals use much smaller amounts of

water they are not usual l}’ considered to be part

of the hydrologic cycle. Both animals and

plants, however, are vital to agriculture, In arid

and semiarid lands, where water often determines survival and production, the efficiency

with which organisms use water has important

implications for sustaining all types of agriculture.

plants have evolved a number of different

ways of coping with water shortages. They may

243
244 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

almost totally escape drought by germinating,

growing, and reproducing before water becomes limited or only after a heavy rainfall.

They may “resist” drought with special anatomical and physiological mechanisms to take

up, store, and retain water. Or they may “tolerate” drought with mechanisms to limit the

destructiveness of internal water deficits.

The relationship between plant growth and

water stress is complex. A number of different

drought-resisting mechanisms may come into

play during a plant’s life, and its sensitivity to

water stress may vary with each. The different

mechanisms may involve disadvantages as well

as advantages. For example, a crop variety with

a short growing season may mature before

drought occurs, but in rainy years its yields are

likely to be less than that of a long-season variety. This complexity has slowed the development of drought-resistant agricultural plants.

Animals exhibit a similar range of adaptations to limited water supplies. Some, such as

kangaroo rats, may never drink water, obtaining moisture instead from their diet or even

from dew, and excreting little water.

In order to be meaningful, comparisons of

these and other differences in water use must

include both the amount of crop, forage, or

animal produced and the amount of water

used. The concept of water-use efficiency

(WUE) allows this comparison. As a general

measure of efficiency, this term applies equally

well to plants and animals, but it is seldom applied to animals because their relative water

use is small.

Plant Water-Use Efficiency

For plants, biological WUE is defined as the

total dry weight of plant material produced per

total water lost by transpiration. Agronomists

often use a different definition of WUE known

as “agronomic WUE, ” which is the amount of

harvestable or economic biomass produced per

water lost by transpiration and evaporation.

These two definitions allow distinctions to be

made between inherent biological processes

and the processes and conditions that apply to

plants grown as crops (19).

Instantaneous measures of WUE are not

meaningful, since plants constantly adjust

water use to changing environmental conditions, Over the entire season, however, biological WUE is relatively constant for a given

species. Variations are common among species

(table 57); these differences relate to time of

year that plants grow, evolutionary history, and

plant physiology. For example, grasses as a

group tend to use water more efficiently than

shrubs (27). But individual species of droughtadapted shrubs may use water more efficiently than some grass species.

Attempts to increase WUE by altering either

photosynthesis or transpiration have usually

failed, For instance, antitranspirants, chemicals that reduce transpiration, have been investigated extensively but have not been widely

used (14). While they can decrease transpiration effectively, they do not increase WUE

because they also reduce photosynthesis and

thus plant growth. There may be site-specific

circumstances in which this is not a disadvantage, such as in the control of plants along

streams.

Table 57.—Comparison of the Total Amount of

Biomass Produced per Total Amount of Water Used

in Transpiration for Crop Plants

Biological water-use efficiency has been divided by potential

evapotranspiration in order to correct for climatic differences.

Biological water-use efficiency

with climatic correction Photosynthetic

Crop (kg/ha/da) a

type

Alfalfa . . . 63, 90 C3

Oats . 90 C3

Soybean . 102 C3

Potato . . . 106 C3

Barley . . 106 C3

Wheat . 112 C3

Corn . . . . 151,213 C4

Sorghum 200,240 C4

Millet. . . . 198,260 — C4

aKllograms/hectare/day

SOURCE Wayne R Jordan, Ronald J Newton, and D W Rains, “Biological Water

Use Efficiency in Dryiand Agriculture,” OTA commissioned Paper,

1982), table 1A, Original sources” L. J Briggs and H. L Shantz, “The

Water Requirement of Plants II A Review of the Literature, ” U S.

Department of Agriculture, Bureau of Plant Industry Bulletin 285, 1913,

C B Tanner, and T. R Sinclair, “Efficient Water Use in Crop Production, H M Taylor, W R. Jordan, and T R Sinclair (eds ) (Madison, Wis.’

American Society of Agronomy, 1983), H L. Shantz and L. N. Piemeisel,

“The Water Requirement of Plants at Akron, Colorado,” Journal of Agricultural Research 34:1093-1190, 1927, R. J Hanks, “Yield and Water

Use Relationships An Overview, ” Limitations to Efficient Water Use

in Crop Production, H M. Taylor, W R. Jordan, and T R Sinclair (eds. )

(Madison, Wis. American Society of Agronomy, 1983)
.-

Ch. /X—Technologies Affecting Water-Use Efficiency of Plants and Animals 245 —

water-use improvements in the past have

often resulted from increases in agronomic

WUE because of the flexibility plants show in

allocating resources into different plant parts.

For example, tepary beans respond to overirrigation by producing leaves instead of seeds.

While biological WUE remains unaffected,

agronomic WUE is decreased. Since beans are

the desired product, a knowledge of agronomic

WUE is more important to crop management

and breeding. Also, crops can be managed to

minimize soil evaporation or to change crop

maturity to shift yields to before or after

drought occurs. Both changes can increase

agronomic WUE.

Animal Water Use

Significant differences exist in the amount

of water required by different livestock and

wildlife species (table 58). Some animals require large amounts of freshwater for drinking. Others require little drinking water, since

they can reduce water requirements when it

is limited, conserve available water, or acquire

most of their needs from food. A list of animals,

in order of increasing adaptation to drought

would be water buffalo, European cattle, African (zebu) cattle, wool sheep, hair sheep, goats,

and camels (28). Water use also will vary depending on the nature of the forage and weather conditions.

Because animals use comparatively little water, there has been little effort to use or breed

animals that use less water. Instead, efforts

have concentrated on ways to increase the efficiency with which animals convert plant biomass into their own. As long as water use remains unaffected, this process improves

animal WUE,

Biological v. economic (agronomic) yield also

applies to herds and single animals. Maintenance costs, in terms of water and food, are

substantial for many single animals. In some

cases breeding populations are maintained

from year to year and their requirements must

be counted in total water- and forage-use effiBox T.—Three Carbons, Four Carbons, and Cam: Plant Physiology and Water Use

Plant biological WUE falls into three broad categories corresponding to differences in photosynthesis: CAM, CA, and CS types. These processes, by which sunlight is converted into organic matter, are different enough to affect many features. CAM, or crassulacean acid metabolism, plants

use water most frugally. Stomata open at night when evaporative demand of the air is low but,

if water is plentiful, many CAM plants also take up carbon dioxide during the day, and water use

increases dramatically. Maximum growth rates of CAM plants such as cacti are low because of

very low photosynthetic rates. Pineapple, the only agricultural CAM plant, is more productive than

most. A large number of food and forage plants use four-carbon, or C4

, physiology and have intermediate biological WUE—e.g., corn, sorghum, grain amaranth, and many warm-season range

grasses. They have high photosynthetic rates and accumulate dry matter quickly. Most of the cereal

grains, almost all woody trees, many vegetables, and cool-season range grasses belong to the the

three-carbon, or C3

, group. This group has the lowest biological water-use efficiency and also is

least effective in retaining the carbon absorbed.

These fundamental physiological differences have not been exploited agronomically yet. Few

CAM species are of economic value now, but they may have potential for specific, high-value products. While four-carbon species are efficient water users, they also grow best during hot summers

and therefore consume large amounts of water over the total season. These species are generally

sensitive to low temperatures, so they cannot be planted earlier or later to reduce summertime

water demands. Attempts to breed hybrids with the best features of each type have so far failed.

SOURCES: James R. Ehleringer, “Photosynthesis and Photorespiration Biochemistry, Physiology and Ecological Implications, “ Hortscience 14(3] .217222. 1979;

James R Gilley and Elias Fereres-Casteil, “ Efficient Use of Water on the Farm, ” OTA commissioned paper, 1982, Wayne R Jordan, Ronald J Newton

and D W. Rains, “Biological Water Use Efficiency in Dryland Agriculture, ” OTA commissioned paper, 1982
246 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 58.—Comparative Water Use Of Animals

Low daily water turnovers reflect a high water-use efficiency. Thus, the animals listed first use the least

water

Body weight Daily water turnover

Animal (kg) (ml/kg

082 ) Environment

Antelope:

oryx . . . . . . . . . . . . . . . ~ ~ . . ~ . . ~ 136 70 African grassland

Wildebeest. . . . . . . . . . . . . . . . . . . 175 137 African grassland

Kongoni . . . . . . . . . . . . . . . . . . . . . 88 116 African grassland

Eland . . . . . . . . . . . . . . . . . . . . . . . 247 213 African grassland

Goat:

Somali . . . . . . . . . . . . . . . . . . . . . . 40 185 African desert

Camel:

Somali . . . . . . . . . . . . . . . . . . . . . . 520 188 African desert

Sheep:

Dorper . . . . . . . . . . . . . . . . . . . . . . 42 170 African grassland

Merino . . . . . . . . . . . . . . . . . . . . . . 38 180 African grassland

Ogaden. . . . . . . . . . . . . . . . . . . . . 31 197 African desert

Karakul . . . . . . . . . . . . . . . . . . . . . . 31 205 African grassland

Cattle:

Boran . . . . . . . . . . . . . . . . . . . . . . . 417 224 African grassland

Boran . . . . . . . . . . . . . . . . . . . . . . . 197 347 African desert

SOURCE L. A Stoddart, A. D Smith, and T W Box, Range Management (New York: McGraw-Hill Book Co, 1975), p 318. (Original

source Mac Farlane. “Prospects for New Animal Industries: Functions of Mammals in the And Zone, ” Proceedings

of the South Australian Water Research Foundation (Adelaide, S Australia, 1972).)

ciency of the herd. Of the animals slaughtered, selected for “agronomic” efficiency: faster and

only a portion is economic yield. About 50 per- greater weight gains in marketable products

cent of an animal is used for meat, while by- per total nutrients spent for animal mainteproducts of various kinds account for another nance.

15 to 20 percent. Like plants, animals have been

THE TECHNOLOGIES

Methods of Improving

and AnimaIs

Biotechnologies

INTRODUCTION

The term “biotechnology” has come to represent a cluster of methods for introducing and

reproducing new genetic variation in bacteria,

plants, and animals as well as a number of industrial applications of biological processes. In

this section, only those technologies are considered that may increase the WUE of agricultural plants. The application of similar technologies to animals is discussed under “Animal

Breeding. ”

The promising technologies include tissue

culture and other techniques for propagating

organisms; fusion of plant cells (protoplasts)

either within or between

recombination of DNA,

species; and precise

the genetic material

(figs. 57 and 58). These methods usually involve

intensive laboratory treatment and may be used

alone, in conjunction with one another, or with

more conventional breeding methods.

ASSESSMENT

The application of various kinds of biotechnology to the specific problems of water use

in arid and semiarid lands involves manipulation of the mechanisms that influence the uptake, use, and loss of water by organisms, For

example, some experts speculate that the

drought tolerance present in some western

weeds could be added to unrelated crops. O r

perhaps cell lines selected for salt tolerance

could produce crops for irrigated areas with

salt accumulation.
Ch. IX–Technologies Affecting Water-Use Efficiency of P/ants and Animals . 247

—

Figure 57.— Working With Protoplasts

“Clones” of a parent plant can be regenerated from its

isolated protoplasts by the methods developed for culturing

tissues as shown here. Protoplasm fusion Involves an additional step: protoplasts of two genetically unlike parents

would be combined at step 4. The offspring are not like either

parent, they often contain unique combinations of genetic

material that could not be produced with conventional plantbreeding methods.

9

Small terminal leaves are first removed from a young

potato plant (1). The leaves are placed in a solution containing a combination of enzymes capable of dissolving the cell

walI (2). Another substance in the solution causes the protoplasts to withdraw from the cell wall and to become

spherical, thereby protecting the Iiving protoplasm during the

disintegration of the wall (3). The isolated protoplants are next

transferred to a culture medium (4), where they grow, synthesize new cell walls and begin to divide (5). After about 2 weeks

of culture each protoplant has given rise to a clump of modifier-estimated cells, called a microcallus (6). The microcalluses

are transferred to a second culture medium, where they

develop into full-size calluses (7). At this stage the cells of the

callus begin to differentiate, forming a primordial shoot (8).

The shoot develops into a small plant with roots in a third

culture medium and is then planted in soil (9).

SOURCE James F Shepard The Regeneration of Potato Plants From Leaf.

Cell Protoplasts, Scientific American 246156 May 1982

Some of these technologies are rapidly entering agriculture. Tissue culture is already in

commercial use and, in the next 10 to 15 years,

is likely to make important contributions (23).

Other biotechnologies face a potentially long

period of basic research before their applications will be available. Protoplasm fusion, like

other more complex techniques, cannot be

used now with much expectation that the

desired results will occur. Recombinant DNA

technology holds the most promise for precisely changing plant features, but it is farthest

away from wide-scale development. Few practical applications of these technologies are expected within the next decade.

Institutional constraints exist in addition to

the technical ones. There is concern, for example, that reliance on laboratory practices

might narrow the genetic diversity of present

crops to an undesirable degree. On the other

hand, some believe that human-induced variation and the germplasm banks that might

spring up could actually increase genetic diversity. Other concerns regarding the release of

novel and potentially dangerous organisms into

the environment have diminished. For example, experience has shown that safeguards

are generally adequate to contain potentially

troublesome organisms used in industry.

These technologies have already had an important effect on the way agricultural research

is conducted. Some private universities and

corporations are involved in agriculture for the

first time. Few of these leading-research institutions are also involved directly in arid land

studies. Furthermore, rapid industrial expansion has created at least a short-term shortage

of trained personnel. As scientists and technicians move rapidly into the private sector,

universities are concerned that their ability to

conduct basic research and to train new teachers will be jeopardized. It is not clear to what

extent the large involvement by profitmaking

corporations may shape research priorities. If

public sector research—e.g., at land grant

universities, USDA laboratories, and State agricultural experiment stations—does not keep

pace, there may be little progress in the application of new biological technology to problems

of social importance that have little foreseeable

profit. Also, since new life forms can be

patented, there is concern that limited access

to the results of private research may further

limit public work,
248 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

——. . — — —

Figure 58.-The Technique of Recombinant DNA Technology

2 Tissues

1(3 Plasmld I

13 Laboratory scale

fermentation

/{

ASOURCE: U.S. Congress, Office of Technology Assessment, The Impacts of Applied Genetics (Washington, D. C.: US Government Printing Office, OTA-HR-132, 1981),

p. 6; and Genentech, Inc

No consensus exists on biotechnology’s nearterm potential in agriculture. While much

former skepticism has been allayed, these are

capital-intensive enterprises that are capturing

large amounts of public research money at a

time when funds are limited. Therefore, the

fear exists that less glamorous technologies—

e.g., new approaches to classical plant breeding

—will be overlooked.

Tissue Culture

Tissue culture is basic to the use of the other

biotechnologies discussed here and to making

the results of such biotechnologies available to

agricultural scientists. It is accomplished by

several methods (fig 57). In its simplest form,

individual sexual cells such as pollen grains

and eggs are stored and grown in artificial

nutrient media, More complex methods allow

identical plants to be developed from pieces of

the parent after they receive several hormone

treatments. In another type of culture, the initial unspecialized tissue, or callus, developed

from a plant cutting is agitated to separate the

cells; a new plant then regenerates from each

cell. This more productive method can also be

used to expose genetic variation among the individual cells of a single parent plant. If environmental stress is applied then to the

culture, the survivors can be regenerated. This

method may have important applications for

problems of water stress.

Many important crop and forage plants can

be regenerated from cuttings with these technologies. Strawberries, asparagus, pineapple,

coffee, and horticultural plants are mass produced this way. More recently, mass propagation of alfalfa, jojoba, and some grass species
—

Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals 249 — — — — —

Photo credits: USDA-Agricultural Research Service

Wheat plants growing using tissue culture: white clump (left) are cells forming from live wheat anthers, masses of

undifferentiated tissue growfrom the cells (center test tube), in a special growing medium (right test tube ‘and flask in

right photo), a small plant develops from the cultured tissue.

has become possible. The savings in time and

space can be substantial. For example, 25

gallons (about 100 liters) of Douglas fir cells in

nutrient media can produce enough plants in

3 months to reforest about 120,000 acres of

land (12).

When tissue culture techniques are used in

conjunction with classical breeding methods,

new germplasm can be made available rapidly, and the volume of material accumulated by

difficult crosses can be increased quickly. For

example, 65 new types of potatoes have been

“cloned” from Russet Burbank cells and more

than 134 virus-tree potato cultures have been

developed.

A number of water-related stresses can be applied to plant-cell cultures, including salinity,

drought, flooding, ion toxicities, nutrient deficiencies, and temperature extremes. Cell lines

with resistance can be developed from the survivors. Recent experiments suggest that cell

selection may provide researchers with material less susceptible to water stress (19). For example, alfalfa and rice cell lines have been obtained that tolerate 2 percent sodium chloride,

a salt concentration lethal to nonselected cells,

Gene dosage, or the number of duplicate sets

of genetic material present within a given

organism, can also be altered by treati ng

cultured cells with chemicals. Varieties of rye

differing only in gene dosage varied in susceptibility to cold and observations suggest that

a similar relationship holds for susceptibilit y

to water stress.

These treatments of plant cultures are recent,

so it is difficult to evaluate their eventual im25-160 0 - 17 : QL 3
250 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— .

“pacts. Sodium chloride tolerance in cell lines,

for example, is sometimes unstable and does

not occur in later generations. In other cases,

important water-related features characterize

the whole plant but not isolated cells and

tissues. Selection for these traits cannot be accomplished in cell culture.

Protoplasm Fusion

If single plant cells in cultures are treated further to remove the tough cell wall, protoplasts

remain. Protoplasts can then be combined, a

crude way of creating new mixtures of genetic material that normally are prevented by

natural breeding barriers (fig. 57). This method

has been used with petunias, plants in the cabbage family, and tomato/potato pairs (pomatoes). Protoplasts from more distantly related

species, such as tobacco and soybean, also have

been induced to fuse. So far, it is possible to

complete the necessary steps—strip the plant

cell wall, alter the protoplasm, regrow a cell

wall, form a callus, and regenerate the plant—

for only a few species. Until the fusion process

is further refined, the features of the new plant

will be unpredictable combinations of the

parents.

This technique holds promise for creating

unconventional hybrids before the more precise recombinant DNA technology is available.

Combinations such as “pomatoes” do not have

commercial value now, but investigators hope

that closer crosses may. Wild relatives of crop

plants often possess desirable features that

adapt them to stress, but natural barriers exist

to sexual crosses. For example, disease-resistant wild relatives often cannot breed with commercial potatoes. Protoplasm fusion may be able

to add this desirable genetic material to

potatoes without breeding (25). The same process, or recombinant DNA techniques, may be

applicable to the transfer of water-related

characters such as changes in growth rate and

production of “heat-shock” proteins (6).

Recombinant DNA

Recombinant DNA technology uses enzymes

to break apart the genetic material (DNA molecules) in one organism and recombine it with

Photo credits: USDA.Soil Conservation Service

The grama grasses are important native Western forage plants. Biotechnologies such as tissue culture and conventional

plant breeding are used for these types of plants as well as for the major annual crops
Ch. IX—Techno/ogies Affecting Water-Use Efficiency of Plants and Animals . 251

—

DNA pieces from another (fig. 58). The “recombined” material expresses new predetermined

characteristics in the organism into which it

is inserted. This process takes place in four

stages:

1.

2.

3.

4.

Desirable genes are chosen and “vectors”

are identified to carry them to the host.

The gene is prepared for splicing into the

vector.

The vector is inserted and maintained in

the host.

A number of hosts are cloned and the most

desirable is selected for further modification or conventional breeding.

This methodology is far from routine for

plants. The lack of vector systems and problems with regenerating whole plants have

hindered progress. The genetic material of

micro-organisms is simpler and transfers of

DNA among bacteria or yeast are common.

Therefore, near-term agricultural applications

are likely to involve only microbes, either

directly or as models for higher plants. For example, bacterial osmoregulation has been manipulated by moving the gene for proline production into nonproline-producing microorganisms. The recipient bacterium increased

its rate of nitrogen fixation while water

stressed (21). Since osmoregulation is the process by which organisms control the uptake of

water, it is crucial where water is limited.

Ultimately, all agriculture depends on carbon compounds “fixed” by plants from atmospheric carbon dioxide. Bacterial carbon

dioxide fixation systems are considered to be

models for plant systems, and preliminary

studies suggest that bacterial systems can be

altered by genetic manipulation (3). Attempts

focus on reducing photorespiration of C3

plants, the process by which about 40 percent

of the energy acquired by plants is lost before

organisms can use it.

Recombinant DNA techniques are often

more difficult to use with plants than with

bacteria and yeasts. In plants, the genetic

material is confined within a nucleus, and

there are few vectors for passing genetic

material from the nucleus of one plant cell to

another, The first genes were inserted across

natural reproductive barriers between plant

species in 1973, but the ability to transfer plant

genes at will is some time away.

Because of these constraints the thrust of recombinant DNA work in plants is developing

laboratory techniques and understanding basic

plant physiology. Much of the success of past

plant-breeding programs relied on the transfer

of large segments of genetic material. A clear

knowledge of the DNA-level changes was not

necessary. Recombinant DNA work requires

that the role of transferred genetic material be

understood if it is to achieve its purpose and

have successful agricultural applications. This

is not possible now.

Classical Plant Breeding

INTRODUCTION

Plant breeders have traditionally worked

with whole plants instead of the cells or

molecules that characterize biotechnology.

Plant breeding generally involves six steps:

1.

2.

3.

4.

5.

6.

choosing the crop for breeding,

identifying the breeding goal,

selecting methods to reach that goal,

exchanging genetic material among organisms,

evaluating the resulting offspring under

field conditions, and

producing seed for distribution to producers.

Some technical parts of these steps have

changed little over time: hand-pollination to

cross similar plants, data collection from extensive field plots, and identification, by art as

well as science, of the most promising young

plants. New methods have changed other steps

a great deal. Centralized research and seed production centers, single-crop specialists, collections of worldwide germplasm, and modern

statistical evaluation have changed the face of

contemporary plant breeding. The availability

of genetic engineering technology promises to

make even more changes.

The philosophical basis for crop-plant breeding, which is fundamentally important in the
252 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—— —

initial steps, may also be changing. For example, the ability to be productive under harsh

environmental conditions, such as those imposed by drought, has not been a major breeding goal for most crop species. In fact, most

plant breeding has involved selecting plants for

superior yield in fertile environments or under

other conditions of high external inputs (7).

This approach assumes that plants which have

high yields under irrigation or high fertilization will also have high yields when water- or

nutrient-stressed. General plant adaptability is

sought to a range of conditions. This is the most

common approach to crop breeding and, for

dryland crops, it has increased yields without

affecting agronomic WUE (10). In some cases,

this type of plant breeding has reduced genetic variability for those factors, such as nitrogen

fixation, stress tolerance, and photosynthetic

efficiency, that may be beneficial in arid and

semiarid environments.

Another approach to plant breeding seeks,

in the case of water shortages, to enhance

drought resistance in a manner similar to that

used successfully for disease and insect

resistance (fig. 59). Key features that confer

resistance are identified and incorporated into

less adapted varieties. Plant selection and

evaluation are carried out under the same

water-limited conditions that the crops are expected to endure because:

Breeding lines that use water efficiently in

a dry environment may not do as well as other

lines under more favorable water conditions,

This is because tradeoffs exist regarding plant

responses in different environments. Therefore selecting plants for wide adaptability may

be selecting for mediocrity. As a result, the

most promising route for plant improvement

under drought stress probably involves selection under water-limiting conditions (17).

Breeding programs of this type are common

for forage plants, but similar ones for annual

crops constitute only a fraction of the total

breeding effort. Because these programs are

new, they have yet to demonstrate their superiority to the first, more traditional, approach.

They have the potential, though, for making

major contributions to agricultural production

Figure 59.—A Generalized Method for Developing

Drought-Resistant and Drought-Susceptible Plants

Repeat as above for second

cycle of recurrent selection

because of the large geographic areas devoted

to production of forage plants and the major

areas of cultivated cropland that are susceptible to environmental limitations (table 59),

ASSESSMENT

Plant breeding for annual crops in the United

States has a long and productive history. Experts estimate that crop improvements have accounted for gains of 1 to 3 percent in yields

per acre each year for corn, wheat, soybeans,

cotton, and sorghum (19). Yield increases have
—

Ch. IX—Techno/ogies Affecting Water-Use Efficiency of P/ants and Animals . 253 —

Table 59.— Percent of the United States With Soils

Subject to Environmental Limitations

Environmental limitation Area affected (o/o)

Drought ., . ~ . . . . . . . . . . 25.3

Shallowness . . . . . . . . . . . 19.6

Cold . . . . . . . . . . . . . . . . . 16.5

Wet . . . . . . . . . . . . . . . . . 15.7

Alkaline salts . . . . . . . . . . . . . 2.9

Saline or no soil . . . . . 4,5

Other, . . . . . . . . . . . . . . . . . . 3.4

None . . . . . . . . . . . . . . . . . . 12.1

SOURCE J S. Boyer, Plant Productivity and Environment,” Science 218445,

Oct 29 1982

come from gradually altering combinations of

traits.

These include modifications of the partitioning of plant substances among organs and compounds, changes in seed retention characters,

and alterations in the timing of flowering and

of seed formation. For example, economic

yield is usually a fraction of total plant dry matter, including roots (table 60). The size of the

fraction depends on the plant species, water

supply, and management. A significant portion

of the yield increases obtained by plant breeding have been based on increasing this fraction,

In wheat, the proportion of harvestable grain

has increased from 35 to 50 percent over the

last 20 years (4). Selection pressure in other

plants would result in similar increases up to

Table 60.— Proportion of Crop Dry Matter Produced

That is a Harvestable Product

‘Plant breeding has successfully Increased the proportion of plantproduced dry matter that IS a harvestable product The figures

given below are for highly productive Irrigated varieties

Proportion economic

Crop Product product (in percent)

Cotton .. .-., . . . . . lint ‘- 8-12

Sunflower . . . . . . . . seed 20-30

Bean ... . . . . grain 25-35

Tomato ., ... . . . . . . fruit 25-35

Soybean . . . . . . . . . grain 30-40

Sorghum ... . . ., . . grain 30-40

Corn . . . . . . . grain 35-45

Sugarbeet . . . . sugar 35-45

Wheat ... ., . . . grain 35-45

Rice ... ... . . . . . . . grain 40-50

Pineapple ... . . . . . . . . fruit 50-60

Potato . . . tuber 55-65

Alfalfa ... . . . . . . . . hay 40-80 — .-

SOURCE Adapted from Wayne R Jordan Ronald J Newton, and D W Rains

“Biological Water Use Efficiency in Dryland Agriculture, ” OTA commissioned paper 1982 p A 7, table 3A

the limits established by the anatomy of the

crop. When these increases do not increase

evaporation or transpiration, they result in

higher agronomic WUE,

Until recently, little research has been conducted on range plants, but work in Utah, Montana, and the SCS Plant Materials Centers on

plants for mined land reclamation has vitalized

range-plant breeding. Vigorous, palatable,

quickly established hybrid grasses are now

available. Perennial range-plant breeding differs from breeding annual crop plants in several ways: survival, as well as production, is

important; only enough seeds are needed to ensure genetic mixing and reseeding; and storage reserves for the next season’s growth cannot be shunted into production. These requirements make breeding more complex,

Identification of the character or characters

to be modified is the single most critical step

in plant improvement; it dictates both breeding

and evaluation methodology. Once characters

are identified, breeders have been successful

because they make selections from vast numbers of plants. One breeding program that uses

computer-assisted seeding and harvesting allows seven staff members to test 30,000 plots

of plants in four locations (29). Large selections

may be important, especially for breeding

drought resistance, since it probably involves

many genes with small, difficult to measure,

effects.

In many cases, the fundamental mechanisms

of adaptation to water stress are not known,

where critical features can be identified for

breeding, they are not based on one or a few

genes, unlike the many disease- and insectresistance traits used successfull y in past

breeding programs. Instead, the complex physiological and biochemical features that enable

a plant to tolerate water stress vary from species to species. The properties that enable one

plant to survive in an arid region—e.g,, a large

root system—may make another susceptible to

severe dedication, or drying,

Under such conditions, accurate laboratory

measurements of the actual physiological feature that confers drought resistance may re-
254 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—. —. — —

quire hours. Measurement technologies are too

time-consuming for the large numbers of plants

needed for mass evaluations. Therefore, direct

plant breeding for the biological characters that

determine drought resistance awaits development of better laboratory technology. This

problem can be overcome by correlating these

physiological features with ones more readily

observed and measured. Such genetic markers

are used to identify some genetic diseases in

humans and in animal breeding programs.

With adoption of the 1970 Plant Variety Protection Act and its 1980 amendments, institutional constraints to the development of new

plant varieties decreased. Private investment

has increased, and several times as many cotton, wheat, corn, and soybean varieties are being produced as before its passage. Other concerns remain, however. The trend for small

seed companies to be taken over by large ones

concentrates economic power in fewer hands.

There is concern that this may increase seed

prices or hinder development of varieties that

have fewer customers or require fewer of a

company’s other products—e.g., pesticides.

Fears also exist that the new systems for patenting germplasm will decrease germplasm

availability at a time when it is needed (5).

Animal Breeding

INTRODUCTION

Animal production is a major feature of

Western agriculture. Large acreages in the

West cannot be cultivated because of erosion

hazards or other factors. For these lands, production of animal protein or other products by

ruminants (goats, cattle, sheep, wildlife) is a

beneficial use of unique resources. Also, large

numbers of cattle are raised on Western feedlots. In both cases, animal breeding can increase productivity.

The major focus of most animal-breeding

programs is increasing the amount of animal

biomass produced per unit of land area or per

amount of plant material consumed. This can

be accomplished by increasing the number of

young animals produced each year or by increasing the rate at which each offspring gains

weight.

Some breeding programs are related specifically to conditions prevailing in arid and

semiarid lands. For example, several new

breeds have been established to achieve greater

heat tolerance for Western rangelands. These

have involved the introduction of African and

Asian sheep and cattle germplasm into European stock, the common rangeland breeds.

Santa Gertrudis, Beefmaster and Africander

cattle, and Dorper sheep resulted from these

crosses.

Standard animal-breeding technologies have

been used to accomplish these goals: introduction of new breeds to create hybrids, intentional selection for high growth rates among

pure breeds, and development of composite

populations. A variety of more intensive technologies are also finding their way into the

livestock industry.

ASSESSMENT

The productivity of ruminant farm animals

has increased substantially during the past two

decades. For example, selection for growth and

carcass traits within beef cattle breeds has

changed some traits by 2 to 3 percent every

generation. Additional increases in productivity have been obtained by crossing several cattle breeds: calf weight was increased by 20 to

25 percent in a three-breed rotational breeding

program, These programs have used European

breeds such as the Simmental, Gelbviech, and

Maine Angou, which are larger and later maturing. Other programs use Texas Longhorns

to decrease calving difficulty, increase disease

resistance, increase fertility, and adapt the

animals to the harsh environmental conditions

that often prevail on open rangelands.

More intensive technologies, first used by the

dairy cattle industry, are being adopted for

other animals. Artificial insemination has

markedly increased milk production, and over

50 percent of dairy cattle are bred this way, Artificial insemination is used for only 3 percent

of beef cattle, but recent treatments to synchronize ovulation promise to decrease labor requirements and make it more acceptable (20).

For those 3 percent, though, artificial insemination has dramatically improved weight, quality and disease resistance.
Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals ● 255

Photo credit: IUDA-Soil Conservation Service

Texas longhorns, after hundreds of years of years of fending for themselves on the arid and semiarid ranges of Mexico,

became the foundation of the U.S cattle industry. They were almost replaced by European cattle breeds in the 20th

century but interest in these hardy animals is increasing now

These improvements are being enhanced by

embryo transfer and storage, methods similar

to those used for plant-tissue culture. In embryo transfer, genetically superior cows are

treated with hormones and, as a result, produce

6 to 20 eggs instead of one. These eggs are

removed, fertilized with semen from a genetically desirable bull, and transferred to surrogate mother cows. All of the calves will be

related to the superior genetic parents but will

also acquire the disease-resistance of the surrogate mother.

Some additional embryo manipulations are

possible before transplantation. New genetic

combinations can be made by combining two

embryos, or one embryo can be divided to produce identical twins. All of these processes are

complex and expensive. They require laboratory facilities, trained embryologists, and about

$2,000 for each procedure. These techniques

have developed in conjunction with embryo

storage methods. It is now possible to freeze

embryos, conserving important genetic resources on a worldwide basis. Frozen embryos

are often used in embryo transfer, and new

technologies promise to make both procedures

less expensive and more widely available. For

example, Rio Vista Farms in Texas have perfected a method of transferring frozen embryos

in plastic straws filled with protective fluid.

With these, thawing and implantation can be
256 Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—.

done by veterinarians or less specialized per- Innovative Applications

sonnel. the Technologies

Some of this technology is not equally available to ranches of different sizes and incomes.

Smaller farms and ranches cannot usually

manage the complicated rotational breeding

programs that increase productivity. Since

about 70 percent of the beef cattle in the United

States are in herds of fewer than 100 animals,

a large number of animals may be excluded,

Composite populations of animals developed

from a wide germplasm base selected from

several breeds would make the advantages of

hybrid vigor available to small cattle operators

perhaps for the first time.

The cattle industry is in transition now, and

changing economic conditions will affect the

availability of credit and the location of livestock centers. Some people expect that the

West will decline as a center for cattle feeding

but retain its prominence in rangeland cow/calf

operations (Ii). A continuing need will exist

for animal germplasm suited for arid and semiarid rangelands, but declining markets for red

meat may have unexpected effects on livestock

producers.

“NeW Crops": Plants and Animals

The greatest service which can be rendered

any country is to add a useful plant to its

culture . . . .

Thomas Jefferson, 1821

The domesticated plants and animals raised

by American farmers and ranchers frequently change. Seventy years ago avocados were

virtually unknown, soybeans were grown only

in a few States, research on grain sorghum had

barely begun, and European cattle were relative newcomers: Now each of these organisms

is well established, filling demands for highvalue or drought-adapted human and animal

food.

Concern remains that other agricultural

plants and animals are needed. These are:

 present agricultural organisms need diversification with new genetic material to prevent attack by new diseases and pests;

Box U.—Sunflowers: A Successful New Crop

Sunflowers are native American plants that, under some conditions, possess environmental

and economic advantages over other crops in the northern Great Plains: they offer drought and

flood resistance and tolerance for salinity and frost. Several North American Indian tribes used

sunflowers extensively but large-scale commercial development of sunflowers occurred first in

Europe. In 1964 the U.S.S.R. released the first high-oil variety, stimulating U.S. interest. Then,

in the late 1960’s, the sharp decline in Russian exports opened the European market to U.S. exporters. At the same time, several universities, USDA, and a commodity organization increased

the agronomic and economic attractiveness of the crop. Since then, U.S. acreage has expanded

65 times to about 4 million acres. In North Dakota, South Dakota, and Minnesota, the major producing States, sunflowers have maintained their economic edge over other small grains, stood up

to adverse weather conditions, and provided growers with an alternative crop. In 1980, a future’s

market was established, and other countries became eligible for financial assistance for U.S.

sunflower purchases. While acreage continues to fluctuate, the future of sunflowers appears bright.

SOURCES: Gary L. Laidig and J. W. Twigg, “Historical Crop Studies,” Feasibility of lntroducing New Crops: Production, Marketing, Consumption (PMC) Systems,

E.G. Knox and A. A. Theison (eds.) (Emmaus, Pa.: Rodale Press 1981), pp. 174191; E.D. Putt, “History and Present World Status,” Sunflower Science

and Technology, J. F. Carter (ed.) (Madison, Wis,: American Society of Agronomy, 1978), pp. 1-29.
Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals ● 257

● current domesticated plants and animals

are too demanding on the environment;

● conventional crops, forages, and livestock

require unacceptably high energy inputs

in the form of fuel, nutrients, pesticides,

irrigation, or disease prevention; and

● the lack of diversified markets exposes

farmers and ranchers to large foreign and

domestic price instabilities.

Some of these concerns have been shown to

be valid. For example, large geographic areas

planted in hybrids with a common genetic

background caused the rapid spread of corn

blight in the 1970’s, resulting in a nearly nationwide crop failure. Disease-resistant

material in a germplasm bank was used to

breed resistant plants for the next season,

preventing the problem from continuing. A

greater diversity of agricultural plants and

animals serve as long-term investments and insurance for the future if they can alleviate such

problems.

In the short term, different crops and forage

plants and animals may be able to provide new

profitable products and to diversify agricultural

markets. Some plant products may provide unusual and high-value chemicals for the pharmaceutical, chemical, or energy industries,

creating benefits for farmers and the Nation

where such crops replace subsidized excess

commodities or ones that exhaust important

resources.

Some experts feel that “new” crops are

needed especially for the arid and semiarid

regions of the United States. Of the established

crop plants, only barley, wheat, sorghum, certain beans, and cotton are adapted to dry conditions. Some of these have been bred for high

production under heavy irrigation, decreasing
258 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—— . —...—— — — —— . —

their adaptation to drought. Other established

crops, such as hybrid corn, were not originally arid-land plants and may have inherent limitations in genetic material.

Opportunities exist today for examining the

potential of new plants and animals because

of the uncertainty facing agriculture in the

West, In some places irrigation is no longer

possible. Lands need improvement to reach

higher levels of productivity in other areas.

Even in the large areas of the West that are too

dry and prone to erosion for conventional tillage and harvest, it maybe possible to increase

agricultural productivity without jeopardizing

important national resources. To this end, welladapted plants and animals are being examined, often for production without irrigation,

heavy fertilization or other large inputs.

ASSESSMENT

A study for the National Science Foundation

identified 54 potential crops. Either these

plants are adapted to environmental stress or

provide a product critical to the needs of

American society. Seven specifically are suited

for arid or semiarid climates (table 61). Other

authors have suggested additional potential

crops for arid or semiarid zones. For example,

Johnston (18) estimates that good evidence for

medical usefulness exists for about 300 plant

species of the Southwestern United States.

The status of these plants varies widely,

Some, such as amaranth, tepary beans, guar,

and cowpea, have a long history of use in the

Americas. Therefore, they are new only to conventional agriculture. These plants are already

domesticated, and their cultivation is well

developed for certain types of agriculture. A

sizable ethnic market exists for these products,

and supply cannot meet demand. Now these

old crops are ready for new and wider uses.

Other arid/semiarid-land plants are now being domesticated, Some are at early stages of

development (jojoba, guayule, saltbush), whereas others are undergoing basic preliminary research (kochia, buffalo gourd, milkweed, Euphorbia, most medicinal plants).

The potential contribution to national productivity is not known for many of these crops.

Preliminary assessments of biomass production indicate that levels are about one-fourth

to one-half that expected from irrigated crops

(19,22), but productivity would be expected to

increase with plant breeding (table 62), Highproduction levels over wide areas may not be

the goal for all crops, however. Some, such as

the traditional varieties used by Papago desert

farmers, may be best cultivated on smaller

scales to maintain sources of already-adapted

germplasm.

Table 61 .—Information on Potential New Crops for Arid and Semiarid Lands

Potential

magnitude and

significance

Life Part

Crop span used

Xerophytes:

Buffalo gourd. . . Perennial Seed

Market

competition

Land use

competition

Cultural

operations

Needed

Product Adaptation work

Protein and

edible oil

Latex

Soybean Dry Desert Mechanized Large Agronomic

Machinery

Guayule . . . . . . . Perennial Stem, Agronomic

root

Jojoba . . . . . . Perennial Seed

Synthetic

rubber

Spermwhale oil

Other

beans

Cowpea

Dry Cotton Mechanized Large

Industrial

oil

Vegetable

Dry,

infertile

Dry

Desert Hand labor Large Agronomic

Machinery

Mung bean . . . . . Annual Seed Sorghum Mechanized Medium Agronomic

Pigeon pea . . . . . Perennial/ Seed

annual

Pinyon pine ... Perennial Seed

Bean Dry,

infertile

Dry

Peanuts Mechanized Small Agronomic

Demand

Agronomic

Machinery

Agronomic

Demand

Nut Nuts Forest Hand labor Medium

Tepary bean ... Annual Seed Bean Other

beans

Dry,

infertile

Range Mechanized Small

SOURCE Soil and Land Use Technology, Inc., A A. Theisen, E G. Knox, and F. L. Mann (eds.), Feasibility of Introducing Food Crops Better Adapted to Environmental

Stress” (Washington, D.C U S Government Printing Office NSF/RA/780289, 1978), vol. 1, p 53, table 8.
Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals 259

— —

Table 62.— Results of “New” Crop Experiments

Production Water available in

Crop (Ib/acre) growing region (in)

Amaranth (grain) . . . . . . . 1,790 Not known (India)

Cowpeas (seeds) . . . . . . . 895 5-1o

Guar (seeds) . . . . . . . . . . 625-805 16-35

Mesquite . . . . . . . . . . . . . . 1,790 12-16

12,530 24

Guayule . . . . . . . . . . . . . . . 1,790-3,580 Irrigated

Kochia . . . . . . . . . . . . . . . . 9,845 16

Russian thistle . . . . . . . . 5,370-9,845 Not known

Saltbush . . . . . . . . . . . . . . 7,160 Not known (UT)

5,370 Not known (TX)

Present crops . . . . . . . . . . 22,375 Irrigated

SOURCE Various sources cited in: Wayne R Jordan, Ronald J Newton, and D. W.

Rains, “Biological Water Use Efficiency in Dryland Agriculture,” OTA

commissioned paper, 1982 )

The development of “new” animals has received less attention than plants. Individual

ranchers are experimenting with previously

unused animals such as elk. Generally, these

efforts are not well known and the people involved are isolated from one another and from

the established animal science community.

These plants and animals face barriers of

several kinds if they are to be used widely.

Domestication, when necessary, is a timeconsuming process, but sophisticated technology should shorten it significantly. Tissue

culture techniques and other biotechnologies

may contribute to the rapid development and

dissemination of new germplasm and organisms. However, more formidable barriers—

both technical and institutional—exist. A great

deal of research remains to be done for many

of the species described here, and there is little evidence to suggest that major Federal or

State initiatives will be forthcoming. Often, extensive field testing has not been completed.

Once these crops produce acceptable yields

under field conditions, they must be attractive

to producers and must find markets. There

have been previous attempts, both successful

and unsuccessful, to introduce new crops. Experience shows that markets and the institutional infrastructure for adoption are crucial

to success. For example, processing plants may

be required, commodity organizations maybe

necessary, consumers may have to be educated

about new products, and marketing channels

from farm to consumer may have to be developed (fig, 60). Even then, the adoption of a new

crop is unlikely to be entirely predictable,

Once a market for a new product exists,

germplasm will probably be available to all interested growers. At the early stages of introduction, however, new crop production may

be limited to large landowners with the capital

and interest for major new ventures. For plants

with industrial uses, this may require corporations to develop processing facilities first, then

to obtain raw plant materials from local farmers on a contract basis or to grow them on their

own land.

Generally, there are few legal barriers to the

introduction of new crops or animals. A major exception, however, relates to reclamation

of arid and semiarid surface-mined lands. Both

Federal and State laws restrict the kinds of nonnative plant species that may be used for

mineland revegetation. Therefore, potential

new crop or forage plants that are not U.S.

natives often cannot be included in some of the

largest research programs and experimental

plantings. Similarly, State laws that regulate

ownership of wildlife and Federal regulations

that control slaughtering and quarantine of imported organisms are cases where the adoption

of technology is restricted legally. While these

legal restrictions are small compared to the

social and economic barriers faced by new

products, they can be significant.

Generally, these drought-adapted agricultural

products have the potential for tailoring agriculture more closely to prevailing environmental conditions. Where resources—e.g,, soils or

water—are being used faster than they are

replenished, adapted organisms hold hope for

a more sustainable type of agriculture, For example, desert milkweeds may be able to replace

dryland crops in the western Great Plains

where increasing energy costs are eliminating

irrigation (1). Or, where fragile lands have been

plowed for annual crops and severe erosion

has resulted, adapted perennial shrubs, grasses,

and forbs may provide profitable products

without land degradation. Such potentials are

usually long term. Few of the crops discussed
. .

260 Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Figure 60.—The Complex Production, Marketing, and Consumption Scheme For a New Crop

Commercial Market. This Diagram Illustrates a Potential Strategy for Jojoba Producers and

Entering the

Processors

+

I

SOURCE: G. L Laidig, “Jojoba. Simmondsia chinensis,” Feasibility of Introducing New Crops: Production-Marketing-Consumption (PMC) Systems, E. G Know

and A A. Theison (eds.) (Columbia, Md.: Soil and Land- Use Technology, Inc., 1981), pp. 74-101. -
Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals ● 261

.-

Box V.—Rules, Regulations, and “New” Agricultural Plants

Federal and State laws restrict the types of plants that maybe used for reclamation of surfacemined lands. These legal limitations have had unexpected results on rangeland research programs.

The primary intent of most laws was to ensure a self-sustaining and persistent plant ground

cover to protect soils. For example, Wyoming law requires that mine operators:

. . . establish . . . permanent vegetative cover of the same diverse seasonal variety native to the

area or of a species that will support the approved post-mining land use. This cover shall be capable

of stabilizing the soil.

Wyoming law did not seek to prevent the use of all nonnative plant species but only those that:

1) were not self-renewing and required special management for persistence, or 2) gave a false impression of reclamation success and might encourage damaging early grazing. The unintended

result of the law, however, was the limitation of introduced plants in many reclamation and

rangeland programs.

Is this desirable? The question is still being debated. Some contend that the focus on using

and improving native forage plants is long overdue and that it might lead to new styles of agriculture more adapted to arid/semiarid regions. Others believe that plant specialists should have

worldwide germplasm at their disposal and that introduced plants may provide important new

additions to American agriculture. For the time being, constraints on the use of nonnative plants

provide an uncommon example of legal limitations on plant research.

SOURCE: Wyoming Department of Environmental Quality. Land Quality Division Rules and Regulations ch. IV.3.D.(2), August 1962.

here, with the possible exception of grain

amaranth, are on the verge of becoming major national commodities, but timely research

and development are likely to provide important payoffs with sustained support. The domesticated desert crops such as cowpea and

tepary bean, since they are adapted for cultivation now and have developed markets, deserve

especially close examination.

Plants for Food and Forage

Grain amaranth was a staple crop of Central

American Indians before colonizers, in order

to eradicate native cultures, methodically destroyed the fields. The remaining amaranth

germplasm is highly variable, providing rich

materials with which to work. Amaranth could

provide biomass energy, seed starch, or leafy

vegetables, but its high-protein grain is most

promising. Both leaves and seeds contain proteins rich in lysine and methionine, amino

acids that limit protein digestion in other grains

(table 63). Amaranth is well suited to semiarid

conditions but not to prolonged or excessive

drought; some plants are adapted to nutrientTable 63.—The Protein Content and Quality

of Various Grains

Protein Limiting Relative protein score

Grain (%) amino acid(s) (100 points optimum)

Amaranth . . 15 Leucine 67

Barley . . . . . 9 Lysine 58

Buckwheat . . 12 Leucine 83

Corn . . . . . . . . 9 Lysine 35

Oats . . . . . . . . 15 Lysine 62

Rice . . . . . . . 7 Lysine 69

Soybeans . . 34 Methionine, 89

cysteine

Wheat . . . . . . 14 Lysine 47

SOURCE: J P. Senft, “Protein Quality of Amaranth Grain, ” Proceedings of the

Second Amaranth Conference (Emmaus, Pa Rodale Press, Inc 1980),

p 45

deficient soils but others require substantial fertilization, An accelerated program of amaranth

research and development is underway at the

Organic Gardening and Farming Research

Center in Emmaus, Pa. The National Academy

of Sciences and the National Science Foundation sponsor amaranth research and USDA is

also showing interest (30).

Cowpeas, grown for their dry seeds in semiarid regions of the world, sometimes produce

seeds in years when drought causes other crops
262 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Photo credit: Rodale Press, Inc.

This grain amaranth plant was selected

for its compact form

to fail. Cowpea vegetation makes excellent hay,

and cowpea’s high-protein seeds can be used

as animal protein concentrates. Green cowpeas

are used now in the U.S. commercial canning

industry.

Buffalo gourds are native undomesticated

plants with wide distribution in the Western

United States. Each plant produces an abundant crop of gourds with oil and protein-rich

seeds and plant roots contain high-quality

starch (table 64). Its vines are a potential forage

that can be repeatedly harvested. It is also

reported to contain medicinal compounds. Domestication programs began for buffalo gourd

in 1973 at the University of Arizona.

Plants for Biomass Energy

Current energy prices do not encourage the

development of biomass crops. Some experts

believe that fragile arid and semiarid lands

Table 64.-Starch and Moisture Content of

Several Sources of Starch

Moisture Starch

Name of starch Source (

0

/ 0 ) (%0)

Buffalo

gourda root . . Cucurbita foetidissima 68-72 15-17

Potato . . . . . . . . Solarium tuberosum 75-78 19

Tapioca . . . . . . . Manihot utilissima 60-75 12-33

Arrowroot . . . . . Maranta arundinaceae 65-75 22-28 b

aOnly buffalo gourd is an arid-land plant.

Industrial starch yield Is typically 15 percent owing to cell structure.

SOURCE: W. P. Bemis, J. W. Berry, and Charles W. Weber, “The Buffalo Gourd:

A Potential Arid Land Crop,” New Agricultural Crops, G. A. Ritchie (cd.)

(Boulder, Colo.: Westview Press, 1979), p. 85.

should not be used for biomass production

under most circumstances. But conditions may

change, and with appropriate safeguards, the

following plants may have potential for producing biomass and other products.

Mesquites are a diverse group of woody

legumes from North and South America. While

they are commonly considered pests by ranchers, they have a long history of use for wood,

flour, and fuel by other cultures. Mesquite

grows in areas of low rainfall by tapping

ground water, thus creating a potential problem in some areas. Annual yields are currently low and plants are usually sensitive to low

temperatures. But mesquite is one of the few

nitrogen-fixing legumes that can tolerate salinities equivalent to seawater and its diversity

provides material from which to breed improved varieties.

Saltbush is a common Western droughtresistant shrub. Many species have protein

concentrations equivalent to that of alfalfa so

it is important for forage. It has also been important in revegetating disturbed lands.

Kochia (tumbleweed) and Russian thistle are

both “weeds” with potential for biomass fuel

as well as forage. Their reputation as weeds

may hamper acceptability but it can also be exploited for high productivity.

In other cases, agricultural residues can be

used for biomass energy, plant and animal residue have potential (15).
Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals ● 263

Plants for Industrial Products

Guar is a leafy annual legume that produces

gum and forage. Guar gum is a strengthening

and stabilizing agent in paper, cosmetics, processed foods, and industrial materials. Older

plants withstand drought, and plant seeds withstand alkaline or saline conditions. In 1977,

20,000 tons of guar were produced but demand

exceeded supply. U.S. consumption is expected

to be 41,500 tons in 1983 (31).

Guayule is a wild shrub, native to Mexico

and Texas. It is adapted to regions with low

and erratic rainfall. Plant roots and shoots contain rubber comparable to that produced by the

Asian Hevea rubber trees, rubber that cannot

be duplicated synthetically. Guayule appears

to be suitable for mechanized agriculture and

requires little fertilization. It is not very salt

tolerant, and guayule plantations are currently susceptible to insects and diseases. The

Native Latex Commercialization Act of 1978

(Public Law 95-592) was designed to stimulate

guayule production, and the commercial rubber industry is involved in guayule research

and development. Two other sources of arid/

semiarid lands natural rubber are rabbitbrush

and sunflowers.

Soaps for shampoos are extracted from various species of yucca, and wax obtained from

the seeds of jojoba is used for a variety of

cosmetics. Neither plant has been cultivated

in the United States but relatives of the yucca

are grown in other parts of the world. Jojoba

grows in Arizona, California, and Mexico on

infertile or saline soils where rainfall is scarce.

Jojoba wax is a substitute for sperm whale oil,

with a large number of potential commercial

uses in the cosmetic, pharmaceutical, and machinery industries. The first large-scale irrigated commercial jojoba plantations are expected to come into production in the Southwest in 1983. At that time the price for seeds

should decrease, and the high-volume, low-cost

lubricant market should open.

Many species of plants produce copious

amounts of hydrocarbons that can provide

chemicals or be cracked to liquid fuels. The

principal species under development are milkweeds, gopherweed, and rabbitbrushes. Milkweeds could provide a variety of chemical

products such as inositol and pectin and

perhaps stimulate development of a honey bee

industry. Gopherweed produces a milky latex

that can be harvested without destroying the

plant. Candelilla produces a wax with a high

melting point, and is a product imported from

Mexico. Candelilla wax sells for $4.19 per

kilogram ($1.90/lb) and the market is good (9).

Animals for Arid and Semiarid Lands

The American bison, or buffalo, was once the

most important large grazer of Western lands.

Bison have recovered from near extinction,

and several large public and private herds now

exist (table 65). Buffalo ranchers suggest that

these animals are more adapted to grazing on

semiarid lands than are their domestic counterparts, They claim that buffalo use low-productivity resources frugally, produce high-quality

meat, and generally exhibit greater hardiness

than do domestic livestock.

Rabbits also have potential as new agricultural animals. They have short gestation

periods, multiple births, and short parenting

time. None of these features is shared with major domesticated animals of rangelands, and

such characteristics provide the fastest way to

increase animal productivity per unit of plant

productivity (table 66). Rabbit farming is now

practiced on a small scale, but the potential for

open-range ranching is unknown. Control, containment, and slaughtering methods have not

Table 65.—Buffalo Sales in 1981

Number of Average

Sale animals a

price

Dakota Heritage Buffalo Sale,

Mitchell, S. Dak.. . . . . . . . . . . . . . . . 131 $572

Wichita Mountains Wildlife Refuge,

Cache, Okla. . . . . . . . . . . . . . . . . . . . 123 $487

Kansas Fish and Game

Commission, Canton, Kans. . . . . . 56 $582

Custer State Park

Hermosa, S. Dak. . . . . . . . . . . . . . . . 470 $444

Durham Ranch . . . . . . . . . . . . . . . . . . . 700 b

aThese figures include only one of the many private herds

Average price not available, individual price range $450 to $1,000

SOURCE. National Buffalo Association, “1981 Sales Results,” Buffalo 10(1), 1982,

pp 8-9
264 . Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— . —

Table 66.—A Comparison of Cattle, Sheep and

Rabbit Production on Western Rangelands

Feature Rabbits Sheep CattIe

Offspring/100 females . . 1,485 120 90

Weight per offspring (kg). . 1 39 182

Population replaced

annually (0

/0). . . . . . . . . . . 30 20 10

Offspring harvested

annually/100 females . . . 1,455 100 80

Harvested weight/

female (kg) . . . . . . . . . . . . 13 39 145

Energy use per individual

(kcal) . . . . . . . . . . . . . . . . . 200,000 1,600,000 9,000,000

Energy use per kg of

offspring (kcal) . . . . . . . . 19,000 40,000 62,000

SOURCE Adapted from C W Cook, “Use of Rangeland for Future Meat Production, ” Journal of Animal Science 451480, 1977, table 4

been developed, and large populations of uncontrolled rabbits have sometimes become major pests. Limited markets are a major constraint to developing a Western rabbit industry.

Limited experiments are underway on replacing single-species domestic livestock with

mixtures of species. The highest potential for

these approaches appears to be on rangelands

where multiple use is important (ch. XI).

SaIt-Tolerant Organisms

INTRODUCTION

Salts occur in agricultural soils for a number

of reasons. Some soils and ground water supplies are naturally saline, and both soils and

water can gain salt from agricultural practices

such as fertilization and irrigation. These processes are heightened in arid and semiarid

lands. High rates of evaporation and transpiration return pure water to the atmosphere, leaving salts behind. The chemical characteristics

of the salts vary. Chloride salts of sodium (table

salt), calcium, and magnesium are all common,

but sulfates and carbonates sometimes may replace the chloride ions. Large areas of nonirrigated croplands and rangelands in the northern Great Plains are experiencing salinity problems, but irrigated areas, especially in California and Arizona, are most affected.

Usually plant growth suffers once soils or

water are salinized. Salty water is difficult for

plants to extract from soils, and such soils often

contain high levels of potentially toxic ions (24).

Most common agricultural plants cannot tolerate salinities of 10 to 20 percent seawater.

Many are sensitive to even lower concentrations (table 67).

The productive life of salinized areas could

be extended by careful and intensive management. Current management technology, such

as drain installation or periodic flushing with

large amounts of water, has emphasized an

engineering approach. Often this is costly in

terms of dollars, energy, and water. Economically feasible engineering approaches do not

eliminate salt; they only minimize it. Therefore,

some experts believe that the development of

salt-tolerant crops would provide an important

biological method to supplement current management technologies. These plants might be

suitable for land currently too saline for agriculture, or they might be irrigated with lower

quality irrigation water, thus “saving” higher

quality water for use on those plants that require it.

The use of salt-tolerant organisms is not limited to flowering plants. A number of programs

are underway that use algae and micro-organisms to produce biomass for food or energy

in brackish or saltwater culture. Both indoor

and outdoor systems are used. Such systems

could be used in conjunction with carbon dioxide emissions from coal generators or saltgradient ponds to increase productivity or to

generate solar energy (26) and would be

another way to produce agricultural products

while using water too salty for most current

crops.

Proponents of these technologies do not advocate increasing the salinity of soil or water

nor the indiscriminate use of saltwater irrigation. Instead they stress the need for continuous evaluation and careful management

ASSESSMENT

There are two approaches to developing salttolerant flowering plants: adding genetic salt

tolerance to conventional crop and forage

plants or developing naturally salt-tolerant, or

halophytic, plants into productive agricultural

species (fig. 61).
.

Ch. IX—Technologies Affecting Water-Use Efficiency of P/ants and Animals ● 265

— — -——————

Table 67.—Salt Tolerance of Crops

Salt tolerance

Type of crop Low Medium High

Fruit Avocado

Lemon

Strawberry

Peach, apricot

Almond, plum

Prune, grapefruit

Orange, apple, pear

Vegetables . . . . . . . . . . Green bean

Celery

Radish

Forages . . . . . . . . . . . . . Burnet

Red clover

Meadow foxtail

White Dutch Clover

Field Crops . . . . . . . . . . Field bean

Cantaloupe

Date

Olive

Fig

Pomegranate

Cucumber, squash

peas, onion

Carrot, potato

Sweet corn

Lettuce

Cauliflower

Bell pepper

Cabbage

Broccoli

Tomato

Milkvetch

Sour clover

Meadow fescue

Oats (hay)

Wheat (hay)

Rye (hay)

Tall fescue

Alfalfa, Sudan grass

Mountain brome

White sweet clover

Castor bean

Sunflower

Flax, corn

Sorghum (grain)

Rice, oats (grain

Wheat (grain)

Rye (grain)

Date palm

Spinach

Aspragus

Kale

Garden beet

Barley

Western wheat

grass

Canada wild rye

Bermuda grass

Nuttall alkali

grass

Salt grass

Cotton, rape

Sugar beet

Barley (grain

SOURCE” D Todd, Ground Water Hydrology 2d ed (New York John Wiley & Sons, Inc., 1980)

Halophytes

Some experts feel that the halophyte approach may be more powerful since halophytes

are adapted already to salty water and soil and

are, in some cases, exceptionally productive (2),

For example, some of these plants are more

productive than alfalfa and grow in water at

least as salty as seawater.

Salt tolerance is scattered widely among wild

flowering plants. Various halophytes are potential forage crops, ornamental, potherbs, vegetables, grains or berries (table 68). All halophytes are not arid- or semiarid-land plants.

However, a world-wide search for promising

desert germplasm resulted in about 1,000 accessions from Argentina, Australia, Brazil,

25-160 0 - 18 : QL 3
266 ● Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Chile, New

Table 68.—Halophytes With Potential for Agricultural Use

Common namea Potential use Comments

Palmer’s saltgrass . . . . . . . . . Grain Used by Cocopa Indians, Gulf of California

Batis . . . . . . . . . . . . . . . . . . . . . Edible root

Cord grass . . . . . . . . . . . . . . . . Forage, grain Feeds cattle, Argentina

Glasswort 23 MTU/ha; seawater irrig.b

Salt bush Forage, grain Seed yield 1 T/ha; 16°/0 protein

Cressa. . . . . . . . . . . . . . . . . . . . Animal feed

Maireana Forage Feeds cattle, Australia

Mesquite . . . . . . . . . . . . . . . . . Forage Feeds livestock, 20,000 ha, Chile

aScientific names are given in the appendix.

bMTU/ha = metric tons per hectare

SOURCE: N. P. Yensen, M. F. Fontes, E P. Glenn, and R. S Felger, “New Salt Tolerant Crops for the Sonorhan Desert,” Desert

Plants 3(3):111-118, G F Somers, “Natural Halophytes as a Potential Resource for New Salt. Tolerant Crops Some

Progress and Prospects, ” The Biosaline Concept, A. Hollaender (cd.) (New York’ Plenum Press, 1979), pp 101.105.

Zealand, Peru, and South Africa.

Twenty-four species were identified from the

Sonoran Desert (32).

Some of these arid-land plants are known to

be useful and edible: they were gathered and

eaten by native people in the past. Most, however, have neither been used nor cultivated. Extensive research is required before they can

make an impact on agriculture, a process that

may take at least 50 years.

Conventional Crops

A wide variety of conventional crops is currently being evaluated for variations in salt

tolerance. Those plants that possess unusually high salt tolerances are being evaluated further. As of 1980, North American research on

such crops occurred at seven U.S. localities

and at least three Canadian sites. The plants

evaluated include alfalfa, cowpeas, mung

beans, melons, cucurbits,’ tomatoes, wheat, lettuce, dates, and grapes. Israeli scientists are

also involved: they are working with tomatoes,

cotton, wheat, and sugar beets, as well as fodder and landscaping plants.

Screening for salt tolerance among only commonly grown varieties of crop plants appears

unpromising. Much of the variability of these

crops in salt tolerance may have been lost during breeding for other traits. Therefore, breeders have turned to the large seed collections

held in germplasm banks around the world.

For example, several thousand barley and

wheat accessions from USDA collections were

screened and irrigated with various dilutions

of seawater in California (13). In some cases,

single species collections are not promising.

Germplasm from wild relatives may be required to supplement the low salt tolerance in

these plants. Because this was true of tomatoes,

crosses were begun with a wild, commercially useless tomato from the Galapagos Islands,

Other scientists are using tissue culture techniques to achieve results, a method that saves

both time and space. For example, millions of

cells, each a potential plant, can be grown in

a 4-inch dish. If the dish contains salty growth

media, only the tolerant cells will survive. This

technique has been used for cell lines of wheat,

oats, and tobacco. Results indicate that enhanced salt tolerance sometimes persists and

can be passed on to offspring. Experiments are

also underway on sugar beets, tomatoes, and

corn. This approach cannot be applied to all

plants now, Some species cannot be cultured

and regenerated yet and other species lose their

capacity for regeneration too quickly (8).

These experiments are preliminary, and it

will be some time before salt-tolerant strains

are ready for commercial use. There is another

disadvantage: it appears now that salt tolerance

is gained at the expense of productivity,

Micro-Organisms

The cultivation of marine and brackish water

algae is short compared to cultivation of agricultural crops on land. Most of the technology

is Asian; major research efforts in Western

countries are recent. Many of the larger species

have been cultivated in offshore beds using
Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Animals 267

—————

biological breakthroughs to supplement older

technology. Smaller organisms, such as microscopic algae, blue-green algae, and bacteria, are

harvested from inland ponds. The latter technologies may be adaptable to arid and semiarid

lands, For example, Mexico produces large

amounts of the high protein, blue-green alga,

Spirulina, in large ponds and processing

facilities and Israeli scientists are experimenting with the same organism in brackish water

ponds in the Negev Desert.

Some of these organisms can be very productive in saltwater. Microalgae used in Hawaiian

experiments produced 60 tons of biomass per

acre per year in small outdoor ponds. Smith

(26) speculates that such ponds would be a way

to use brine left from the process to improve

salty irrigation waters.

General concerns remain about the desirability of developing salt-tolerant crops, regardless

of the method used. It maybe futile to develop

salt-tolerant forages if the plant material is too

salty for animals. Saltwater irrigation presents

other potential problems. Without intensive

management, ground water contamination

may result, decreasing the quality of freshwater, The situations in which salt-tolerant

crops provide an unusual opportunity are limited. Such crops are not a panacea for the mismanagement of irrigated lands.

CONCLUSIONS

A large number of opportunities to improve

agriculture in arid and semiarid lands exists.

Some technologies will not increase production in the usual sense. For example, the ability of plants and animals to survive harsh conditions may sometimes be as important as high

yield. Attempts to decrease total plant water

use have often failed in the past. New approaches, such as plant breeding for environmental stress, are more promising. The biotechnologies are blossoming with unpredictable results. While it is clear that agriculture

is changing, it is not clear how older institutions will adapt to these changes.

The technologies that affect water-use efficiency are powerful, and the choice of goals

to which they are applied is crucial. Efforts to

improve drought resistance of existing agricultural plants and animals is quickening. Perhaps

faster and larger gains can be made by applying these technologies to “new” arid/semiarid

land plants. Rich germplasm from underused

desert crops and wild plants is available to

decrease water use while maintaining agricultural production. Although this is an important

long-term goal, it cannot be achieved immediately.

CHAPTER IX REFERENCES

1. Adams, R. P., “Chemicals From Arid/Semi-arid

Land Plants: Whole Plant Utilization of Milkweeds, ” OTA commissioned paper, draft, 1982.

2. Aller, J. C., and Zaborsky, O. R., “The Biosaline

Concept, ” The Biosaline Concept, A. Hollaender (cd.) (New York: Plenum Press, 1979), pp.

1-15.

3. Anderson, K., “Biochemical Genetics of Ribulose Bisphosphate Carboxylase/oxy genase: High

Frequency Transfer and Chromosome Mobilization by Broad Host Range R. Factors in COZ

Fixing Bacteria, ” Genetic Engineering of Sym -

biotic Nitrogen Fixation and Conservation of

Fixed Nitrogen, J. M. Lyons, et al. (eds.) (New

York: Plenum press, 1981), pp. 249-256.

4. Austin, R. B., Bingham, J., Blackwell, R. D.,

Evans, L. T., Ford, L. T., Morgan, M. A., and

Taylor, M., “Genetic Improvements in Winter

Wheat Yields Since 1900 and Associated Physiological Changes, ” Journal of Agricultural SGience 94:675-689, 1980.

5. Barton, J. H., “The International Breeder’s

Rights System and Crop Plant Innovation,” Science 216:1071-1075, 1982.
268 . Water Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

6.

7,

8.

9.

10.

11.

12.

13,

14,

15,

16<

17(

18

19.

20,

21.

Barton, K. A., and Brill, W. J., “Prospects in

Plant Genetic Engineering, ” Science 219:671-

676, 1983.

Boyer, J, S., “Plant Productivity and the Environment,” Science 218:443-448, 1982.

Chaleff, R. S., “Isolation of Agronomically Useful Mutants From Plant Cell Cultures, ” Science

219:676-682, 1983.

Chemical Market Reporter, Nov. 8, 1982.

Donald, C. M., and Hamblin, J., “The Biological

Yield and Harvest Index of Cereals as Agronomic and Plant Breeding Criteria, ” Advances

in Agronomy 28:361-405, 1966.

Drabenstott, M., and Duncan, M., “The Cattle

Industry in Transition, ” Federal Reserve Bank

of Kansas City Economic Review, July-August

1982, pp. 20-33.

Durzan, D. J., “Progress and Promise in Forest

Genetics, ” Science and Technology . . . The

Cutting Edge, Proceedings, 5t)th Anniversary

Symposium Paper (Appleton, Wis.: Institute of

Paper Chemistry, 1980).

Epstein, E., Norlyn, J. D., Rush, D. W., Kingsbury, R. W., Kelley, D. B., Cunningham G. A.,

and Wrona, A. F., “Saline Culture of Crops: A

Genetic Approach,” Science 210:399-404, 1980.

Gilley, J. R., and Fereres-Castiel, E., “Efficient

Use of Water on the Farm,” OTA commissioned

paper, 1982.

Goodin, J. R., “Biomass Potential in Semi-arid

Lands, ” OTA commissioned paper, May 1982.

Jefferson, T., “The Writings of Thomas Jefferson,” Monticello, Va., H. A. Washington (cd.),

1821, j). 176.

Johnson, D. A., “Improvement of Perennial

Herbaceous Plants for Drought-Stressed Western Rangelands, ” Adaptation of Plants to Water

and High Temperature Stress, N. C. Turner and

P. J. Kramer (eds.) (New York: John Wiley &

Sons), 1980, pp. 179-185.

Johnston, M. C., “Medicinal Plants of the Southwestern United States, ” Arid Land Plant Resources, J. R, Goodin and D. K. Worthington

(eds.) (Lubbock, Tex.: International Center for

Arid Lands Studies, Texas Tech University),

1979, Pp. 179-185.

Jordan, W. R., Newton, R, J,, and Rains, D. W.,

“Biological Water Use Efficiency in Dryland

Agriculture,” OTA commissioned paper, 1982.

Laster, D,, “Animal Performance, ” OTA commissioned paper, 1983.

LeRuduler, D., Yang, S, S., and Sconka, L., “Pro-

[ine Over-Production Enhances Nitrogenase

Activity Under Osmotic Stress in KlebsieZZa

Pneumonia , Genetic Engineering of Sym-

— ——.

22(

23.

24

25.

26.

27.

28.

29.

30,

31,

32,

biotic Nitrogen Fixation and Conservation of

Fixed Nitrogen, J. M. Lyons, et al, (eds.) (New

York: Plenum Press, 1981), pp. 173-179.

Loomis, R. S., and Gerakis, P. A., “Productivity of Agricultural Ecosystems,” Photosynthesis

and Productivity in Different Environments, J.

P. Cooper (cd.) (London: Cambridge University Press, 1973), pp. 145-172.

National Research Council, Priorities in Biotechnology Research for International Development, proceedings of a workshop, Washington,

D. C., and Berkeley Springs, W. Va., J~ly 26-30,

1982, Board on Science and Technology for International Development (Washington, D. C.:

National Academy Press, 1982).

Rains, D. W., “Salt Tolerance of Plants: Strategies of Biological Systems, ” The 13iosaZine Concept, A. Hollaender (cd. ) (New York: Plenum

Press, 1979), pp. 47-67.

Shepard, J. F., Bidney, D., Barsby T., and Kemble, R., “Genetic Transfer in Plants Through Interspecific Protoplasm Fusion, ” Science 219:

683-688, 1983.

Smith, C. S., “Testimony on Potential Uses of

Saline Waters Derived From the Colorado River

Quality Improvement Program,” U.S. Congress,

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on Water and Power, Committee on Energy and

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185-191.

Sosebee, R. E., Tueller, P. T., and Rittenhouse,

L. R., “Technologies for Increasing Water Use

Efficiency On-Site,” OTA commissioned paper,

1982.

Stoddart, L. A., Smith, A. D., and Box, T. W.,

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Townley-Smith, T. F., and Hurd, E. A., “Testing

and Selecting for Drought Resistance in

Wheat, ” Stress Physiology in Crop Plants, H.

Mussell and R. C. Staples (eds.] (New York:

Wiley Interscience, 1979), pp. 447-464.

U.S. Department of Agriculture, “Hold the

Spinach–Pass the Amaranth,” Food News for

Consumers, winter 1983, p. 6.

Whistler, R. L,, “Industrial Gums From Plants:

Guar and Chia,” Economic Botany 36:195-202,

1982,

Yensen, N. P., Fontes, M. F., Glenn, E. P., and

Felger, R. S., “New Salt Tolerant Crops for the

Sonorhan Desert, ” Desert Plants 3(3):111-118,

1981,
—

Ch. IX—Technologies Affecting Water-Use Efficiency of Plants and Anirnals ● 269

. -.

Appendix 9-1 .—Scientific Names of Potential “New” Agricultural Plants

Crop

Group 1:

Buffalo gourd ... . . . .

Cowpea . . . . . . . . . . . .

Euphorbia . . . . . . . . . .

Grain amaranth. . . . . .

Guar ... . . . . . . . . . . . .

Guayule ... . . . . . . . .

Jojoba . . . . . . . . . . . . . . .

Kochia . . . . . . . . . . . . . . .

Mesquite . . . . . . . . . . . . .

Saltbush . . . . . . . . . . . . .

Group II. Halophytes:

Batis. . . . . . . . . . .

Cord Grass . . .

Cressa . . . . . . . . . . .

Glasswort . . . . . .

Maireana . . . . . . . . . . .

Mesquite . . . . . . . . . . . . .

Palmer’s saltgrass . .

Saltbush . . . . . . . . . . . . .

Scientific name

Cucurbita foetidissima HBK

Vigna unguiculate (L.) Walp.

Euphorbia spp.

Amaranthus spp.

Cyamopis tetragonoloba (L.) Taub

Parthenium argentatum

Simmondsia chinensis (Link) Schneider

Kochia scoparia (L.) Roth

Prosopis spp.

Atriple spp.

Batis rnaritima L.

Spartina Iongispica

Cressa truxillensis

Salicornia europaea L.

Maireana brevifolia

Prosopis algorobo

Disfichiis palmeri (Vasey) Fassett

Atriplex patula, var. hastata — .
Affecting Ground Water

.
Page

The Water Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

Ground Water Use in the Western United States . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

Ground Water Characteristics . . . . . . ..+...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

Western Ground Water Regions.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

Relationships Between Ground and Surface Waters . . . . . . . . . . . . . . . . . . . . . . . . . 276

Ground Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

The Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

Increasing Ground Water Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

Improving Ground Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

Improving Ground Water Withdrawal Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

Limits of Technologies Related to Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

Special Characteristics of Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

Effects of Ground Water Overdrafting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

Chapter Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

List of Tables

Table No. Page

69. The Importance of Ground Water indifferent Western Regions, 1975. . . . . . . . 274

70. Sources and Effects of Dissolved Materials in Ground Water . . . . . . . . . . . . . . . 279

71. Hardness Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

72. Energy Costs for Pumping Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286

73. The Effect of Pumping Efficiency on Pumping Costs . . . . . . . . . . . . . . . . . . . . . . 287

74. Fuels Used for Irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

75. Ground Water Mining in the Western United States . . . . . . . . . . . . . . . . . . . . . . . 292

List of Figures

Figure No. Page

62. Ground and Surface Water Use in the Western United States... . . . . . . . . . . . . 273

63. Ground Water’s Contribution to Various Water Uses, 1975 . . . . . . . . . . . . . . . . . 274

64

65

66

67

68

The Major Ground Water Regions of the Western United States. . . . . . . . . . . . . 277

Depths at Which Saline Ground Water Is Encountered.. . . . . . . . . . . . . . . . . . . . 280

The Hardness of Ground Water in the Western United States . . . . . . . . . . . . . . . 281

Examples of Different Types of Wells... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

Regions of Ground Water Withdrawal in Excess of Recharge.. . . . . . . . . . . . . . . 293
Chapter X

Technologies Affecting Ground Water

Ground water resources have become increasingly important to Western agriculture in

the past decades, since increased use of ground

water allows large new areas of land to be irrigated, Concerns exist that such use is not sustainable over the long term and that more careful decisions must be made to protect the valuable, finite water resource.

This chapter assesses ground water’s role in

agriculture and in other uses in the Western

United States and evaluates technologies associated with its use. The chapter discusses

ground water availability, water-quality degradation, and the interrelated character of

ground and surface water, with emphasis on

broad ground water principles applied to

technologies and problems of the arid and

Ground Water Use in the

Western United States

During the past three decades, ground water

use in the Western United States has almost

tripled, and the percentage of total withdrawals

coming from ground water has nearly doubled,

from 21 percent in 1950 to 39 percent in 1975

(fig. 62). Ninety-six percent of the ground water

used in the entire United States occurs in the

17 Western States. Agriculture, including rural

domestic water use, relies heavily on ground

water (fig. 63), but the absolute and relative

amounts involved vary greatly within the region (table 69),

Major Western aquifer areas in heavy use are

the Ogallala (or “High Plains”) aquifer, which

stretches south from Nebraska to the Texas

panhandle, the aquifers of the interior valleys

of California, and those of the Snake River

plain in Idaho. Each of these ground water

areas supplies a significant percentage of the

total irrigation and domestic water used in

these areas. In other areas, however, the im

-

portance of an individual aquifer is more local.

semiarid West. Technologies designed to

manipulate ground water quantity and quality are discussed separately to reflect the fact

that, in general, water-supply technologies may

involve active management, while water-quality technologies generally require a more passive approach. In practice, this separation seldom exists,

A wealth of information exists on ground

water supplies and quality in the individual

aquifers of the Western United States, but a

regional synthesis was not found in the literature and may not exist. The recent trend

toward sophisticated computer models has produced a competence for detail, but has exacerbated the problem of gaining an overview of

this resource.

SETTING

Figure 62.— Ground and Surface Water Use in the

80

60

t

Surface water use

1950 1955 1960 1965 1970 1975

Year

Ground water withdrawals rose from 21 to 39 percent of

total water withdrawals during the period from 1950 to 1975.

These data include the nine water resource regions of the

West; such trends cannot be sustained.

SOURCE Office of Technology Assessment, 1982 (Original source U S GeoIogical Survey, Estimated Use of Water in the United States, published

at 5-year intervals )

273
274 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

Figure 63.—Ground Water’s Contribution to Various

57

—

—

Data exclude

saline water sources

domestic live- water supplied electric

stock supplies Industrial power

utiIities

In 1975 approximately 96 percent of the water for rural

domestic use came from ground water Rural livestock also

derived a large share of their water from ground water

supplies.

SOURCE: D Todd, Ground Wafer Hydrology, 2d ed. (New York’ John Wiley &

Sons, Inc., 1960). (Original source: C. Richard Murray ‘and E. Bodette

Reeves, Estimated Use of Water in the U.S. in 1975, U.S. Geological

Survey Circular 765, 1977.)

The extent of ground water withdrawals in excess of recharge, or “mining,” is also a local

problem. With the exception of a few areas

(e.g., Texas and Arizona) where obvious declines in the regional water table are being

noted, the relationship between recharge and

pumping is quite speculative.

The perception that ground water is an inexhaustible resource has gradually changed

during the last 30 years. Ground water is increasingly viewed as a finite resource that is

being overdrafted. Both the National Water

Commission (7) and the U.S. Water Resources

Council (WRC) (15) discussed the sustainability of activities based on ground water extraction and concluded that much of the irrigated

agriculture in areas such as Texas, Oklahoma,

and Kansas which are heavily dependent on

ground water (primarily the Ogallala aquifer),

probably are not sustainable. Further study of

this region by the High Plains Associates (5)

outlined some of the effects of diminishing

water and energy resources at the local, State,

regional, and national level.

Ground water overuse and its effects on agriculture (i. e., abandonment of once productive

farmland, higher pumping costs, and land subsidence) are only one element of the perceived

problem, however. The deterioration of ground

water quality, resulting from the infiltration of

agricultural, industrial, and municipal pollutants may be of even greater significance for

future ground water use in the Western United

States. Most rural uses involve untreated water,

and the quality of this water is therefore of

great importance, especially to those users requiring high quality, such as domestic rural

users (ch, IV).

Table 69.—The Importance of Ground Water in Different Western Regions, 1975

Total withdrawal Total withdrawal Percent ground water Overdraft

Region all sources ground water of total withdrawal Total (maf) Percent (maf)

Missouri. . . . . . . . . . . . . . . . . . . . . . . . . .

Arkansas-White-Red. . . . . . . . . . . . . . . .

Texas-Gulf . . . . . . . . . . . . . . . . . . . . . . . .

Rio Grande . . . . . . . . . . . . . . . . . . . . . . .

Upper Colorado . . . . . . . . . . . . . . . . . . .

Lower Colorado . . . . . . . . . . . . . . . . . . .

Great Basin . . . . . . . . . . . . . . . . . . . . . . .

Pacific Northwest . . . . . . . . . . . . . . . . .

California. . . . . . . . . . . . . . . . . . . . . . . . .

42.6

14,4

19.0

7<1

7.7

10.0

9.0

42.0

44.4

11.7

9.9

8.1

2.6

0.1

5.6

1.6

8.2

21.5

27

69

43

37

1.0

56

18

20

48

2.9

6.1

6.3

0.7

0

2.7

0.7

0.7

2.5

24.6

61.7

77.2

28.1

0

48,2

41.5

8.5

11.5

Note: All volumetric data in million acre-feet (maf), conversion from million gallons per day (mgd) and rounded to nearest 0.1 maf.

SOURCE: US Water Resources Council, The Nation’s Water Resources 1975.2000 (Washington, D. C.. U.S Government Printing Office, Summary, vol. 1, 1978), pp. 16-25.
Ch. X—Technologies Affecting Ground Water ● 275

— — — -

Box W.—When the Well Runs Dry-The High Plains Study

In 1976, prompted by concern about the diminishing ground water supplies in the Ogallala aquifer

and possible effects on irrigated agriculture in the six High Plains States (Colorado, Kansas,

Nebraska, New Mexico, Oklahoma, and Texas) underlain by the aquifer, Congress authorized and

funded the High Plains study (Water Resources Development Act of 1976, Public Law 94- 587).

Congress gave major responsibility to the U.S. Department of Commerce; the U.S. Army Corps

of Engineers was assigned the task of planning and evaluating the potential for interbasin transfer

of water to the High Plains.

Five major policy alternatives for the High Plains study were evaluated: 1) no change in public

water policy; 2) increased education and research to improve water use efficiency; 3) new regulations restricting the amount of water pumped for irrigation; 4) intrastate surface water development; and 5) interstate surface water development. The effect of each policy was considered for

total irrigated acres, crop-production volumes, total returns to land and management, number of

acres shifting to dryland production, changes in ground water levels, water use, sales volumes

by economic sector, employment, and population. Values were estimated for the years 1977,1985,

1990, 2000, and 2020.

According to the scenarios developed by the study, projections of future crop production do

not indicate a significant change in the current mix of crops and relative size of their production

volume to 2020. Instead, the problem of ground water depletion and disruption in irrigated crop

production is localized within States. Education and research on water conservation and legal restrictions on pumping could slow depletion of the aquifer. Intrastate and interstate surface water

development also could help slow ground water depletion but would require large economic investments and entail extensive environmental and social costs.

SOURCES: High Plains Associates,‘“Six-State High Plains Ogallala Aquifer Regional Resources Study, Summary.” A Report to the U.S. Department of Commerce

and the High Plains Study Council, July 1982. Raymond J. Supalla, Robert R. Lansford, and Neal R. Gollehon, “’Is the Ogallala Going Dry?,” J. Soil

and Water Cons. 37:310-314.

Ground Water Characteristics

Ground water may result from a number

processes:

1. infiltration of precipitation;

of

2. seepage through the banks and beds of

surface water bodies such as ditches,

rivers, lakes, and oceans;

3. ground water leakage and inflow from adjacent aquifers; and

4. artificial recharge from irrigation, reservoirs, water spreading, and injection

wells,

There

ing, and

that cred

s “misinformation, misunderstandmysticism” (7) about ground water

ts it with occurrence in underground

rivers, pools, and veins, and thus separating

“percolating” underground water from “underground streams. ” Ground water does not

occur in pools or channels of the kinds commonly seen on the surface, with a few exceptions, such as in some limestone or basalt formations. Instead, it is found usually in small

open spaces, or interstices, of subsurface geological formations of rock or unconsolidated

sediment.

Ground water represents a vast and largely

unmeasured natural storage reservoir. Although nearly all rocks contain some water,

rocks that yield significant quantities of water

are known as “aquifers.” The subsurface layers

of the earth, below the soil moisture zone, comprise a great reservoir through which water

moves very slowly. Its journey underground

may be extremely brief or very long. This reservoir acts as a vast natural regulator in the

hydrologic cycle, comparable in its effects to

the oceans. It absorbs some fraction of the rainfall and snowmelt that would otherwise reach

streams and rivers very rapidly as surface runoff, and it maintains streamflow during dry

periods when no surface runoff occurs.
276 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Only a small proportion of the total subsurface zone saturated with ground water is composed of rocks that store and transmit significant amounts of water. A wide range of permeabilities exists, ranging from cavernous limestones that may transmit water in much the

same fashion as surface rivers and streams, to

semipermeable layers that transmit water imperceptibly and that are not important in moving water to a spring or well.

In all cases, the deeper levels of the ground

water zone consist of interstices that are so few

and small that further downward percolation

of water is impossible. Generally, the amounts

of water to be found below a depth of 2,000 to

3,000 ft below the surface are very small, except in exceptional circumstances.

If inflow to a ground water system exactly

equals outflow from that system, storage remains constant and the ground water will be

a renewable resource. Ground water that is

used at a rate in excess of recharge, no matter

what the total available volume may be, is being “mined,” and its use is not renewable.

Agricultural development based on such mining will ultimately be threatened. For example,

irrigated agriculture in the High Plains region

of Texas was based on ground water development. The ground water used for irrigation has

been mined from the Ogallala aquifer in excess

annual recharge to that aquifer. In a period of

slightly more than 20 years, some irrigated

acreage is reverting to nonagricultural uses or

other types of agriculture (e. g., limited irrigation, rangeland agriculture, and dryland farming) as the ground water reserves of the Ogallala aquifer in that area have been depleted or

energy costs of pumping have become prohibitive,

In arid and semiarid areas, ground water inflow from adjacent aquifers, particularly those

found in higher level ground water basins, may

be important in local ground water recharge.

The actual effect of this at a particular site is

difficult to determine without detailed studies

of the meteorological and geological site characteristics. Attempts to recharge overdrafted

aquifers artificially have increased in recent

years, particularly in areas of water shortage

and may be locally significant. *

Western Ground Water Regions

Ground-water resource regions are more difficult to define than are surface-water resource

regions. While surface-water resource regions

may be differentiated on the basis of topographic divides, ground-water resource regions

must be separated on the basis of varying rock

types and surface climate. Arbitrary decisions

concerning the relative importance of these

factors must be made in assigning an area to

a given ground-water resource region. Thus,

various experts may have slightly different

opinions concerning the placement or definition of the controlling factors for a particular

site. A given ground water region may be comprised of a number of surface water basins.

For purposes of this assessment the major

ground-water resource regions of the Western

United States are defined as:

1. Western Mountain Ranges,

2. Alluvial Basins,

3. Columbia Lava Plateau,

4. Colorado Plateaus and Wyoming Basin,

5. High Plains,

6. Unglaciated Central Region, and

7. Glaciated Central Region (fig, 64).

These regions are discussed in detail in appendix B.

Relationships Between Ground and

Surface Waters

The distinction between ground water and

surface water is largely arbitrary. Water moves

between these two environments continuously. It is not accidental that those areas of the

Western United States now experiencing, or

beginning to experience, ground water supply

or quality problems are commonly areas of sur-

*In May 1983, the U.S. House of Representatives passed a

measure (H. R. 71) that would study and establish demonstration projects for ground water recharge in the High Plains. Other

Western States facing ground water depletion were to be included in the study as well.
Ch. X—Technologies Affecting Ground Water ● 277

Figure 64.— The Major Ground Water Regions of the Western United States

SOURCE D Todd Ground Water Hydrology 2d ed (New York John Wiley & Sons Inc 1980)
278 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

——— ———— ————

face water shortage. Only in certain special

geological settings is it possible to decrease the

amount of water contained in one part of the

hydrologic cycle without also decreasing the

amount in others.

Where ground water occurs in direct contact with surface water bodies such as lakes,

ponds, or rivers, there will commonly be a

movement of water between the two. The direction of this movement normally will be determined by the difference in altitude between

the two sources. In arid and semiarid lands,

where evapotranspiration losses normally far

exceed precipitation amounts, the few perennial or intermittent streams are generated

elsewhere and almost without exception lose

water to ground water throughout the desert

sections of their courses. Estimated ground

water recharge in arid and semiarid areas may

be as much as 10 times more effective than direct infiltration of precipitation (9). Therefore,

changes in surface water supplies caused by

technology may have significant consequences

for nearby or distant ground water supplies.

Ground Water Quality

Ground water-quality problems are not

necessarily unique to arid or semiarid areas.

However, some pollution problems may reach

critical levels more quickly than in more humid

areas because of the low recharge rates of drier

areas.

Precipitation reaching the ground contains

only minor amounts of dissolved mineral matter. The quantity and type of mineral matter

dissolved by this precipitated water, once it

reaches the ground, depend on the chemical

composition and physical structure of the rock

or soil on which it falls as well as on the

physical and chemical properties of the precipitation (e.g., temperature, acidity). Carbon dioxide, sulfate, and other natural and human-introduced, acid-forming compounds derived

from the atmosphere and from organic materials in the upper soil layers form weak acids

in combination with water and assist the solvent action of the water as it moves downward.

Most “salts” (dissolved materials) are added

to ground water as a result of soil and rock

weathering (table 70). Excess irrigation water

percolating to the water table may contribute

substantial quantities of salt. Water passing

through the root zone of cultivated areas usually contains salt concentrations several times

that of the applied irrigation water. Increases

result primarily from the evapotranspiration

process, which tends to concentrate the salts

in irrigation waters. In addition, fertilizers,

pesticides, and selective absorption of salts by

plants and soil minerals will modify salt concentrations of percolating waters, Factors governing the increase of dissolved salt content of

percolating waters include soil permeability,

soil chemistry, drainage facilities, amount of

water applied, type of crop(s), and climate,

High concentrations of dissolved substances

may be found in soils and ground water of arid

and semiarid climates, where leaching is not

effective in diluting the solutions. Similarly,

poorly drained areas, particularly basins having interior drainage, such as much of Nevada

and western Utah, often contain high concentrations. In some areas, such as the southern

portion of the Ogallala aquifer in Texas and

Oklahoma, high salinity may be the result of

the original sedimentary deposition of the

rocks under saline or briny waters.

Many ground waters contain salts in such

concentrations as to make them unusable for

ordinary water-supply purposes. Federal drinking-water standards recommend that total dissolved solids not exceed 500 parts per million

(ppm). Specific limits of permissible salt concentrations for irrigation waters cannot be so

precisely stated because of the wide variations

in salinity tolerance among different plants (ch.

IX). In general, a salinity level of 1,000 ppm is

considered a hazard for most irrigation purposes in the United States, although the extent

to which such water can be used successfully

will depend on the quality of the soils involved,

A well-drained soil, in certain cases, may produce a crop even using high-salinity water,

whereas a poorly drained soil may fail to produce a crop using water of a similar or better

quality. Keeping in mind this variability, a ma-
Ch. X—Technologies Affecting

-—

Ground Water ● 279

—

Table 70.—Sources and Effects of Dissolved Materials in Ground Water

Constituent or

physical property

Silica (Si02

)

Iron (Fe)

Calcium (Ca) and

magnesium (Mg)

Sodium (Na) and

potassium (K)

Bicarbonate (HCO) and

carbonate (C02

)

Sulfate (S02)

Chloride (Cl)

Dissolved solids

Hardness as CaC02

calcium carbonate

Acidity or alkalinity

(hydrogen ion concentration, p H )

Dissolved oxygen (O2

Source or cause Significance

Dissolved from practically all rocks

and soils, usually 1 to 30 ppma

Dissolved from most rocks and

soils; also derived from iron

pipes, More than 1 or 2 ppm of

soluble iron in surface water

usually indicates acid wastes

from mine drainage or other

sources

Dissolved from moist soils and

rocks, but especially from limestone, dolomite, and gypsum

Dissolved from most rocks and

soiIs

Action of carbon dioxide in water

on carbonate rocks

Dissolved from many rocks and

soiIs

Dissolved from rocks and soils;

present in sewage and found in

large amounts in ancient brines,

seawater, and industrial brines

Chiefly mineral constituents dissolved from rocks and soils, but

includes organic matter

In most water, nearly all the hardness is due to calcium and

magnesium.

Acids, acid-generating salts, and

free carbon dioxide lower pH.

Carbonates, bicarbonates, hydroxides and phosphates, silicates,

and berates raise pH.

Dissolved in water from air and

from oxygen given off in

photosynthesis by aquatic plants.

Forms hard scale in pipes and boilers and on

blades of steam turbines

On exposure to air, iron in ground water oxidizes to

reddish-brown sediment. More than about 0.3 ppm

stains laundry and utensils. Objectionable for food

processing. Federal drinking-water standards state

that iron and manganese together should not exceed 0.3 ppm. Larger quantities cause unpleasant

taste and favor growth of iron bacteria

Cause most of the hardness and scale-forming

properties of water. Waters low in calcium and

magnesium are desired in electroplating, tanning,

dyeing, and textile manufacturing

Large amounts, in combination with chloride, give a

salty taste, Sodium salts may cause foaming i n

steam boilers, and a high sodium ratio may Iimit the

use of water for irrigation

Produce alkalinity. Bicarbonates of calcium and

magnesium decompose in steam boilers and hotwater facilities to form scale and release corrosive

carbon dioxide gas. In combination with calcium

‘ and magnesium cause carbonate hardness

Sulfate in water containing calcium forms hard scale

in steam boilers. Federal drinking-water standards

recommend that the sulfate content not exceed 250

ppm

In large amounts in combination with sodium gives

salty taste. In large quantities increases the

corrosiveness of water. Federal drinking-water

standards recommend that the chloride content not

exceed 250 ppm

Federal drinking-water standards recommend that

the dissolved solids not exceed 500 ppm. Waters

containing more than 1,000 ppm dissolved solids

are unsuitable for many purposes

Consumes soap before a lather will form. Deposits

soap curd on bathtubs. Hard water forms scale in

boilers, water heaters, and pipes. Hardness

equivalent to the bicarbonate and carbonate is

called carbonate hardness. Any hardness in excess

of that is called noncarbonated hardness

A pH of 7.0 indicates neutrality in a solution. Values

greater than 7.0 denote increasing alkalinity; values

less than 7.0 indicate increasing acidity. Corrosiveness of water generally increases with

decreasing pH

Dissolved oxygen increases the palatability of water.

Under average stream conditions, 4 ppm is usually

necessary to maintain a varied fish fauna i n good

condition. For industrial uses, zero dissolved

oxygen is desirable to inhibit corrosion —— a

ppm parts per million

SOURCE PauI R Ehrlich, Anne H Ehrlich, and John P Holdren, Ecoscience Population, Resources, Envioronment [San Francisco W. H. Freeman & Co , 1977) (Original

source Charles B H u n t Physiography of the United States (San Francisco, W H Freeman & Co , 1967)
280 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —- ———— — —

jor factor affecting the suitability of ground

water for irrigation increasingly will be the

salinity level of the water (fig. 65).

“Hardness,” another effect of the concentration of certain salts in water, also impacts on

the suitability of water for irrigation. Hardness

results from the presence or absence of compounds of calcium and magnesium. The U.S.

Geological Survey (USGS) classifies hardness

according to the amount of calcium carbonate

or its equivalent that would be formed if the

water were evaporated (table 71). “Hardness”

varies across the Western United States (fig.

66).

While hardness is an undesirable characteristic for many uses of water, some hardness is

essential if soil quality is to be maintained. As

water hardness decreases, the calcium and

Table 71 .—Hardness Classification

Parts per million CaC03 Classification

0-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soft

61-120 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Moderately hard

121-180 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hard

More than 180 . . . . . . . . . . . . . . . . . . . . . . Very hard

SOURCE H Baldwin and C McGuinness, A Primer on Ground Water, U S

Geological Survey, 1963

magnesium may be replaced by sodium, which

will react with the soil and reduce its ability

to transmit water. The Salinity Laboratory of

the Department of Agriculture recommends

the use of the Sodium Absorption Ratio (SAR)

index, which measures the ratio of sodium to

calcium and magnesium and can be directly

related to the absorption of sodium by soil.

Water containing as much as 40 percent sodium (relative to the concentration of calcium

Figure 65.— Depths at Which Saline Ground Water Is Encountered

Saline water is defined here to contain more than 1,000 mg/l dissolved salts, a concentration that represents a highsalinity hazard for many irrigated crops.

SOURCE: D Todd, Ground Water Hydrology, 2d ed (New York” John W!ley & Sons, Inc , 1980).
Ch. X— Technologies Affecting Ground Water . 281

Figure 66.— The Hardness of Ground Water in the

Western United States

(areas shown represent average conditions)

Hardness as CaC 02 in mg/l

and magnesium) is classified as “good” for irrigation uses, while values as high as 60 percent are “permissible. ” Sodium levels are generally low throughout the Western United

States, at least in the shallow aquifers, with the

exception of portions of the Texas-Gulf and

Pacific Northwest regions (15), There is some

indication that deeper aquifers of the northern

Great Plains and interior basins of the Western

region may occasionally have higher sodium

levels that would render their use for irrigated

agriculture undesirable.

Human activities may affect the quality of

ground water in two major ways: 1) by accelerating the rate of buildup of compounds or

components normally found in ground water,

and 2) by adding or increasing the concentration of dissolved constituents during beneficia]

use of water, The first results from plowing

fields or any similar action that expedites the

normal movement of water into and through

soils containing soluble compounds. The second results from discharging inorganic chemicals, biological agents, and organic compounds associated with municipal, industrial,

and agricultural uses into the environment

through which water may move. [These are discussed in detail in chapter IV.)*

Detection of ground water-quality degradation depends largely on the existence of monitoring wells. It is highly probable that some

potential sources of ground water pollution in

the Western United States are not located near

a water-quality monitoring station. Knowledge

of the geographical distribution of and contributions to ground water-quality degradation is

incomplete. Many criticisms of the surface

water-quality monitoring network contained i n

the General Accounting Office (GAO) (14) critique apply equally to the ground water-quality

monitoring network. These include problems

related to taking samples at fixed time intervals, which may not coincide with the presence

of the pollutant, and the location of the monitoring well network, which may not coincide

with the potential sources of pollution. Moreover, GAO identified problems related to field

and laboratory inconsistencies in the collection

and analysis of water samples and the types

of data analyses used.

In addition, because the general flow of

ground water is not directly observable but

must be inferred from mathematical models,

the geographical extent of any pollutant source

is much more speculative than is the case with

surface water. It can be assumed that the pollutants in surface waters in any given area will

generally be present in the ground water, modified in some cases by filtering or by chemical

interactions with the soil or aquifer constituents. A more detailed discussion of water quality and its associated public health aspects is

presented in chapter IV.

* Ii ffe(, t\ of d( 1(1 rtiln art? atldl~ zt~(l ill tt)(’ ()’1”.4 ass(’s~lll(’[li: ‘1’1)[’

A’t’gIorl(l/ Impli(’atior?s of ‘f ”ri)rl,\/Jor’t(’(i }’oll[)tdl)ts, 111 ~)rt’~s.

25 – 160 C – 19 : ~11, 3
282 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— .

THE TECHNOLOGIES

Increasing Ground Water Supplies

Effective planning and management of

ground water resources at a particular site

must be based on the characteristics of the associated ground water region or basin within

the region and on the interrelated nature of

ground and surface water. Management objectives must take into account not only the

geology and hydrology of the basin but also the

economic, political, legal, and financial aspects

of managing the water resource. Typically, optimum economic development of the water resources of an area requires an integrated approach that coordinates the use of both ground

and surface water, Such development must consider both the quantity and quality of those resources to be successful.

With the exception of a decision not to extract ground water, most management technologies affecting water quantity may be considered active. They involve attempts to increase

the recharge artificially to the aquifer above

volumes that would occur under natural conditions. Technologies include water spreading

and the use of recharge wells or pumping to

induce recharge from natural surface water

bodies. The choice of a given method, or combination of methods, is highly site-specific and

will be governed by local topographic, geologic,

climatic, and soil conditions; the quantity and

quality of the water to be recharged; and the

ultimate use for the water,

A fundamental requirement for artificial

ground water recharge is that excess water be

available, either locally or by import into a

region, during all or part of each year, Without

a supply of “excess” water during at least some

portion of each year, artificial recharge technologies are not feasible. A number of areas

exist in the Western United States that appear

to have no water supply in excess of existing

use patterns (ch. III). In some of these areas—

for example, southern California and central

Arizona—wastewater is increasingly used for

ground water recharge. The implications of

this practice for water quality are discussed

below and in chapter IV.

Water Spreading

INTRODUCTION

Water spreading involves the construction of

basins, pits, or barriers in or near natural

stream channels to impound water and cause

it to infiltrate the ground surface rather than

leave the basin as surface runoff. This approach is most appropriate where the aquifer

to be recharged is a near-surface, unconsolidated aquifer having few impermeable layers

to impede either the vertical or horizontal flow

of the water.

The typical ground-water recharge basin is

excavated to a depth of 10 ft or more with side

slopes as steep as the soil will allow when

saturated. For some soils, special protection,

such as broken rock, is required at the anticipated water surface to reduce wave erosion

and the resultant turbidity in the water caused

by bank erosion. Small check dams have been

built in stream channels to impound surface

runoff briefly and to increase the wetted surface area of the stream bed.

Experience in the operation of offstream

ground-water recharge basins indicates that the

surface area of the spreading basin is less important than the wetted perimeter. The bank

area is the most important aspect of the wetted

perimeter because falling sediment seems to

clog this area less than on the bottom, The

steeper the side slopes, the greater the recharge

capability. The greater the perimeter of the

basin, the more bank area available. Curvilinear basin sides provide a longer perimeter

and result in a more esthetically pleasing facility in urban areas,

ASSESSMENT

No information is available on the extent of

water spreading in the western United States.

Information is available for two areas in Cal-
—

Ch. X—Technologies Affecting Ground Water ● 283

— .

ifornia, the Tulare Basin and southern California, where a total of 173 off stream basin and

pit facilities were in operation as of 1973. These

produced a total of approximately 892,000 acreft of recharge annually. This amount is an average of Slightly more than 5,000 acre-ft per facility and represents 40 percent of the total recharge that was accomplished in the State of

California during the 1972-73 water year (11).

For these two facilities, the average cost of

operating and maintaining surface recharge

basins was $6.00 to $8.50/acre-ft, plus capital

costs (land acquisition and construction) of

$1.25/acre-ft (1973 dollars). The use of a coagulant to reduce the turbidity* of the influent

water increased the cost of operation by an additional $3.l0/acre-ft. While these results are

site-specific, they illustrate what can be accomplished in one area when recharge basin

technology works and is used intensively.

The two primary limitations on the application of this technology are the availability of

land and the avail ability of unappropriated surface water, In many areas of the Western

United States, one or both of these will effectively make the technology impossible. A further limitation is the lack of a suitable geologic

setting. Recharge basins and pits will work well

only with a near-surface, unconfined aquifer

or in the natural recharge area of the aquifer.

Recharge Wells

INTRODUCTION

A recharge well moves water from the surface to freshwater aquifers. Recharge wells are

a way to increase ground water reserves where

deep, confined aquifers must be recharged, or

in urban areas, where land values preclude the

development of water spreading,

Recent studies on the use and success of recharge wells are scarce. A few regions in the

Western States have experience with this technology. At least 2,000 recharge wells are located in the agricultural lands of Idaho’s Snake

River plain (10), These wells are typically 2 to

3 ft in diameter and 20 to 30 ft deep, and are

capable of accepting flows up to approximately

700,000 ft3 (16 acre-ft) per day. The geology of

the area consists of alternating layers of fractured and permeable basalt, a common volcanic rock. A study of the effect of these disposal

wells on water quality revealed that ground water moved rapidly through fractures and channels in the basalt formations, that bacterial pollution persisted underground, and that suspended solids were reduced by downward percolation.

ASSESSMENT

In California, where artificial recharge is

practiced most extensively of the Western

States, recharge wells accounted for 12 percent

of the recharge projects in 1959 but only 1 percent of the recharged water (8). Davis, et al. (2),

present data showing an annual recharge of approximately 1,100 acre-ft/yr for a single well

in the San Joaquin Valley, but stress the lack

of experimental data. Todd (10) gives average

values ranging from 200 to 400 acre-ft/yr for

six sites in southern California and points out

that the highest rates will occur in highly porous rock formations such as limestone and

lavas.

According to USGS, recharge wells are 6(

. . . justified only where the spreading method is not feasible” (l). Impermeable near-surface layers of rock or soil would render the

spreading method geologically infeasible, while

higher valued uses of land could render it economically infeasible.

For most aquifers, artificial recharge rates

using recharge wells seldom equal pumping

rates. The difficulty lies in the fact that pumping and recharging differ by more than just a

simple change in direction, As water is

pumped from a well, fine material present in

the aquifer is carried through the coarser particles surrounding the well and into the well

where it is removed with the extracted water.

In the reverse direction, any silt carried into

a recharge well will be filtered out by the

coarser materials and will tend to clog the

aquifer surrounding the well, Dissolved air carried to the aquifer by recharge water will
284 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

.

similarly tend to clog the well. Bacteria, which

will be a much more common constituent of

recharge water than of natural ground water,

can form growths on the well screen and the

surrounding rock or soil, thereby reducing the

effective recharge area of the well. The chemistry of the recharge water may not be in equilibrium with the aquifer or the natural ground

water, thus producing chemical reactions that

may reduce the permeability and porosity of

the aquifer. In general, ground water recharge

using wells will only be suitable for highquality, treated water, and considerable experience is required to maintain optimum recharge rates. The recharge well is a technology that is limited to situations where there are

no other options.

Improving Ground Water Quality

lntroduction

In general, technologies to maintain or improve the quality of ground water are largely

designed to prevent pollution. In most cases,

once a ground water source has been polluted,

it responds very poorly to attempts to restore

its original quality,

Water reaches ground water levels by deep

percolation from precipitation falling on the

overlying land surface or through interconnected flow with surface water bodies (see ch.

III). This recharge to ground water aquifers

may be either artificial, as discussed above, inadvertent, or natural. Inadvertent recharge occurs as an unplanned result of some activity

not designed specifically to recharge the

ground water artificially, Included in this category is water from irrigation, cesspools, septic tanks, broken water mains, sewers, landfills,

waste-disposal facilities, canals, and reservoirs.

Whatever the source of recharge, degradation

of the ground water quality may occur if polluted water is introduced. Once it has occurred, ground water pollution may be more

difficult to detect than surface water pollution

because of the relative inaccessibility of the

water. Also, depending on the pollutant and

the natural filtering by the aquifer materials,

the subsurface pollution may be more difficult

. .

to control than surface water pollution, and it

may move within the aquifer and persist for

decades.

Technologies to improve ground water must

be designed for a specific water-quality problem at a specific site. Their success will be

determined by the extent to which the local

geology, ground water movement, and nature

of the contaminant are considered. All waters

contain some amount of either dissolved or

suspended contaminants. Technologies associated with ground water pollution must be

focused largely on preventing pollutants from

entering the ground water system. The sources

of these pollutants are diverse and the list of

potential pollutants is extensive, as discussed

earlier in this chapter and in chapter IV.

One form of ground water pollution that

sometimes may be dealt with technologically

involves the intrusion of seawater into coastal

aquifers. Seawater intrusion initially occurs

when the coastal aquifer is pumped beyond its

natural freshwater recharge capacity (“mined”)

or when freshwater recharge decreases naturally, In either case, seawater displaces or

mixes with the freshwater in the aquifer. As

little as 2 percent of seawater in an aquifer can

render the water unpotable. In the coastal section of Texas and portions of California, for example, this problem already exists to varying

degrees (I 5). The primary technologies for controlling saline water intrusion are:

1.

2.

3.

4.

Modification of pumping patterns, which

typically involves construction of new

wells at a site further inland.

Artificial recharge to balance withdrawals. This normally involves development

of a supplemental water source,

Extraction barriers (a line of pumping

wells along the coastal line), which create

a trough in the water table into which the

seawater flows. This water is then lifted

to the surface and subsequently discharged

back into the sea.

Injection barriers (a line of recharge wells

along the coastal line), which create a

“ridge” of freshwater beyond which the

higher density seawater cannot penetrate,
—

This normally involves development of a

supplemental water source.

Assessment

All technologies designed to improve ground

water quality must be assessed in terms of:

. whether the contamination exists at a concentration sufficient to cause problems for

the intended water use,

● the source of the ground water contamination, and

c the nature of the hydrogeologic environment.

The combinations and severity of impacts are

complex, and in many cases largely undefined,

in view of the current state of knowledge about

ground-water flow regimes and the behavior

of contaminants at a particular site.

pollution potential is largely dependent on

whether the recharge to ground water is taking place above or below the water table.

Elimination above the water table (e.g., by soil

filtering, biological decomposition, chemical

deposition] may be effective for some pollutants, generally organics. The exceptions are the

major inorganic constituents, many organic

pesticides, and viruses. As the types and

volumes of contaminants being introduced into

the ground water system increase, the traditional dependence on the soil as a filtering

agent becomes less feasible. Many organic

chemicals pass through the soil virtually unchanged and viruses may be unaffected by soil

filtering. Thus, many of the contaminants now

being introduced into the ground water system

are effectively permanent for purposes of society’s planning horizon.

The most problematical aspect of ground

water pollution involves the duration of the

decreased water quality and the most effective

form of water-quality treatment. In this regard,

An important aspect of ground water pollution is the fact that it may persist underground

for years, decades, or even centuries. This is

in marked contrast to surface water pollution.

Reclaiming polluted ground water is usually

much more difficult, time consuming, and

expensive than reclaiming polluted surface

Ch. X—Technologies Affecting Ground Water ● 285

water. Underground pollution control is

achieved primarily by the pollution source, and

secondarily by physically’ entrapping and,

when feasible, removing the polluted water

from the underground (10).

In light of this technological limit, the management of ground water quality involves managing the potential sources of ground water

pollution and control before the pollutant is introduced into the ground water system instead

of treating the pollution after it occurs, This

is an extremely complex matter, largely involving adjustments in the ways in which waterborne wastes are disposed rather than the technological means of purifying water once it is

contaminated. With modifications, the technologies for controlling seawater intrusions into

freshwater aquifers may be applied to the removal or isolation of any contaminant,

Improving Ground Water

Withdrawal Efficiency

Introduction

An important consequence of the reliance on

ground water for irrigated agriculture pumping has been the increased cost of obtaining

water from this source. In the 1960’s and early

1970’s, when the rate of withdrawal and overdraft were rising rapidly, concerns grew about

the effects of pumping on the long-term availability of ground water for irrigation. More

recently, the fear of depletion has been displaced by the much more immediate concern

that energy prices will make irrigation with

ground water uneconomical in some areas,

even with much of the water still in the aquifer.

Increasingly, when water must be lifted

several hundred feet, energy costs tend to be

the major component of water costs. The

energy costs of pumping 1 acre-ft of water from

various depths with alternative fuels as well as

fuel prices have increased greatly for some

areas in the last 10 years, and further increases

are projected (table 72).

Assessment

Technologies to improve the efficiency with

which ground water can be pumped from
286 Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—— — ——

Table 72.—Energy Costs for Pumping Ground Water

(1977 constant dollars)

These costs are for pumping 1 acre-ft of ground water from

various depths with alternative fuels and fuel prices for

1970-2000,

Pump Energy costs under

lift alternative fuel prices

Fuel (ft) 1970 1980 2000

Natural gas . . . . . 100 $ 1.13 $ 4.56 $ 9.12

200 2.30 9.29 18.58

300 3.43 13.86 27.72

Electricity . . . . . . 100 7.52 8.88 17.76

200 25.03 17.76 35.52

300 22.55 26.64 53.28

LPG . . . . . . . . . . . . 100 7.32 12.60 26.20

200 14.65 25.20 50.40

300 21.98 37.80 75.59

Diesel . . . . . . . . . . 100 5.24 14.96 29.92

200 10.59 30.00 60.00

300 15.74 44.96 89.92

SOURCE The technical assumptions such as the amount of fuel and the pressure

required to lift an acre-foot of water are based on Gordon Sloggett,

Energy and U S Agriculture” Irrigation Pumping, 1974.77 (Washington,

D.C : U.S Department of Agriculture, September 1979). Other assumptions include a 60-percent pumping efficiency Fuel costs in 1977 constant dollars are natural gas ($/mcf) 0.39 in 1970, 158 in 1960, and 315

in 2000; electricity ($/kWh), 0.033 in 1970, 0.039 in 1980, and 0.078 in

2000 LPG (S/gal) 025 in 1970,043 in 1980, and 0.66 in 2000, diesel (S/gal)

028 in 1970, 080 in 1980, and 160 in 2000. The 1970 prices for LPG,

and diesel are a national average obtained from Agricultural Prices,

Annual Summary (Washington, D C U.S. Department of Agriculture,

June 1977). The 1970 prices for electricity are a national average ob.

tained from Agricultural Prices, October 1977 The 1970 price for natural

gas was obtained by personal communications with Delbert Schwab,

OSU. The 1980 prices reflect average prices paid by farmers in

Nebraska, Kansas, Oklahoma, and Texas in January 1980 The prices

were obtained through phone conversations with officials in those

states Hans Landsberg, project director and co-authors (Energy: The

Next Twenty Years, Cambridge, Mass , Ballinger, 1979, p 71) conclude

that, on average, real fuel prices will double by the year 2000. Although

long-term contracts consummated in the last several years suggest

natural gas prices may rise faster than the prices of the other three

fuels, we have chosen to illustrate the implications of a doubling of

all fuel prices rather than attempt to estimate differential rates of

increase

SOURCE K Frederick, and J Hanson, Wafer for Western Agriculture (Washing.

ton, D C Resources for the Future, 1982)

underground aquifers are necessary to compensate for rising energy costs and declining

water levels. In addition to changing the spacing and depth of wells drilled into the aquifer,

the technologies involved are generally concerned with the type of pump employed and

the fuel or energy source used to drive the

pump. Technologies for improving the efficiency of the water well itself also may be important in certain cases,

IMPROVING PUMPING-SYSTEM EFFICIENCY

Pumping efficiency is the ratio of the theoretical to the actual energy input needed for

a given water output. It is essentially the product of the efficiencies of the pump and the

power unit. A new pump should have an efficiency of about 75 percent when properly installed, Internal combustion engines often

reduce the efficiency of the pumping system

by another 5 percent because of the gearhead.

The power-system efficiency varies widely

with engine type. Reasonable engine efficiencies are 90 percent for electric, 24 percent for

natural gas, and 32 percent for diesel fuel.

Overall attainable efficiencies for pumping

systems are about 66 percent for electric, 17

percent for natural gas, and 20 percent for

diesel (6),

Inefficient pumping systems result in unnecessarily high pumping costs. Recent tests

by the High Plains Underground Water Conservation District No. 1 in Texas showed that

some farmers pay twice or even three times as

much for irrigation because of the sizing, staging, and condition of the pump. oversized

pumps, specifically, were a major source of inefficiency. Commonly, the pumps had been designed years earlier to handle larger quantities

of water than the well could currently yield

(because of lowered water tables). Other

sources of energy loss included improper staging to accommodate changes in water levels

or additional lift requirements of newly installed sprinkler systems and reliance on worn

pumps. The condition of the power unit, especially with natural gas internal combustion

engines, was occasionally the source of some

inefficiency, but those problems were not so

severe as those involving the pumps.

Pump efficiency has a large effect on the cost

of pumping water. According to calculations

by Frederick and Hanson (table 73), energy

costs may rise as much as 40 percent as the

pump efficiency declines from 70 to 50 percent,

and costs may rise another 67 percent with a

decline to 30-percent efficiency. At 1980 energy

costs (deflated to 1977 constant dollars), a decline in pump efficiency to 50 percent costs a

farmer an additional $3.19/acre-ft with electricity compared to the costs of a 70-percent

efficient well.

The type of fuel is as important as the pumping depth in determining a farmer’s energy

costs. Despite a fourfold rise in price since
Ch. X—Technologies Affecting Ground Water ● 287

———

Table 73.—The Effect of Pumping Efficiency

on Pumping Costs (1977 constant dollars)

Energy costs to pump 1 acre-ft of ground water 200 ft with alternative fuels, fuel prices, and pump efficiencies.

Pump Fuel price

Fuel efficiency 1970 1980 2000

Natural gas . . . 70 $ 1.97 $ 7.96 $15.93

50 2.76 11.15 22.30

30 4.60 18.58 37.16

Electricity ., ... . 70 12.88 15.22 30.45

50 18,04 21.31 42.62

30 30.06 35.52 71.04

LPG . . . . . . . 70 12,56 21.60 43.20

50 17,58 30.24 60.48

30 29,30 50.40 100.80

Diesel . . . . . 70 9.08 25.71 51.43

50 12.71 36.00 72.00

30 21.18 60.00 120.00

SOURCE K Frederick and J Hanson, Water for Western Agriculture (Washington,

D C Resources for the Future, 1982)

1970, natural gas continues to be the least expensive means of pumping (table 74). In 1980,

natural gas was only half as expensive as electricity, the next least expensive source of energy. Diesel, as a result of rapid price increases

in the last 2 years, is now the most expensive

fuel.

Electricity accounts for 50 percent of the irrigated acreage served by onfarm pumps, and

within the Pacific region virtually all irrigation

pumps are electric (table 74). Abundant hydropower is the least expensive fuel in the Pacific

Northwest. Electricity is the most important

fuel in the Mountain States (74 percent) and

accounts for substantial acreage in the Plains

States (25 percent). Despite the 15-percent

growth in electricity use between 1974 and

1977, expansion has been hindered because

many electric utilities are near capacity and unwilling to add new irrigation customers because of peak load problems. One option for

such cases might be to limit new customers to

pumping during nonpeak hours.

The most rapid growth has been for diesel

fuel, which increased by 723 percent between

1974 and 1977, Almost all of this growth came

in the northern plains, the only area that uses

substantial amounts of this fuel. Under the

1980 fuel costs listed in table 73, little further

growth in diesel use is expected. Diesel fuel

prices have jumped dramatically since 1978,

and supplies have been erratic, especially at

vital periods in the growing season.

Use of liquefied petroleum gas (LPG) has

been concentrated in the Plains States. Although its use declined from 1974 to 1977, prospects for increased LPG use are good largely

because of the supply or price problems with

the alternatives. LPG prices have not risen like

either diesel or natural gas (table 74), and in

late 1979 there was a world surplus of LPG.

IMPROVING WELL EFFICIENCY

A water well is a hole or shaft, usually vertical, drilled or excavated in the earth to bring

ground water to the surface. Many methods exist for constructing wells. Selection of a particular method depends on the purpose of the

well, the quantity of water required, depth to

ground water, geologic conditions, and economic factors. Shallow wells in unconsolidated

aquifers, such as sand or gravel, may be dug

by hand or machine, bored with an auger or

constructed by driving a perforated pipe into

the material. Deeper wells, or those completed

in consolidated rocks, must be drilled using a

cable tool or rotary drill.

Table 74.—Fuels Used for Irrigation (1,000 acres)

— —

Electricity Diesel Natural gas LPG

Region 1974 1977 1974 1977 1974 1977 1974 1977

Northern Great Plains . . . . . . . . . . . . . . . . . . . . . . . . . . 1,573 2,612 1,543 2,914 2,430 3,231 1,553 1,008

Southern Great Plains. . . . . . . . . . . . . . . . . . . . . . . . . 2,007 2,347 151 166 6,742 6,949 509 568

Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4,297 4,500 307 350 1,152 1,104 184 136

Pacific . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6,197 6,717 4 9 84 31 0 0

17 Western States . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,074 16,176 2,005 3,439 10,409 11,315 2,246 1,712

SOURCE K Frederick and J Hanson, Water for Western Agriculture (Washington, D C Resources for the Future, 1982) (Original source” Gordon Slogget, Energy and

U S Agriculture Irrigation Pumping, 1974-77 AER Report No 436 (Washington, D C U S Department of Agriculture, September 1979)
288 ● Wafer-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

——-—

Photo credit © Ted Spiegel, 1982

Drillers inspect a forest of the latest waterwell drilling rigs at the Pacific Northwest Exposition

of the American Waterwell Association in Reno, Nev.

After a well has been drilled, it must be completed. This can involve the placement of casing, cementing of casing, placement of well

screens, and gravel packing (fig. 67), These

steps are necessary to ensure the stability of

the well walls and to maintain a flow of water

into the well through unconsolidated materials,

Wells in consolidated rocks can often be left

as open holes so that these completion techniques may not be required.

A new well, properly drilled, cased, and developed, should give years of satisfactory service with little attention. Many wells fail, however. They yield less water with time, a situation possibly associated with declining water

tables. Yield decreases may also be a result of

a faulty pump or poor well-construction techniques. Where the well is a factor, technologies

exist that may be used to remedy the problem.

Problems associated with a declining water

supply can sometimes be remedied by deepening the well. Where the problem in reduced

yields is faulty well construction that involves

poor casing connections, improper perforations of the casing, improper screens, incomplete placement of gravel packs, and poorly

seated wells, repairs may be possible. Repairs

to a well with one of these construction prob-
Ch. X—Technologies Affecting Ground Water 289

— —

I
290 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

lems may cost $8 to $12/ft (estimated), whereas

constructing a new well would cost an average

of $25/ft (estimated) (4).

The third and most prevalent cause of well

failure results from corrosion or incrustation

of well screens. These problems are caused by

chemical reactions between the well-casing

materials and the ground water or by precipitation of materials carried in solution by the

ground water. Screens can be cleaned by shooting a string of vibratory explosives in the well

or by adding hydrochloric acid to the well to

dissolve the incrustation, followed by pumping to agitate and surge the water in the well,

Where slime-forming organisms block screens,

particularly in recharge wells, treatment with

chlorine gas or hypochlorite solutions can

remedy the problem. For improving yields of

wells drilled in solid rock, concentrated acid

solutions or shooting with explosives is often

effective.

LIMITS OF TECHNOLOGIES RELATED TO GROUND WATER

Special Characteristics of

Ground Water

Ground water has certain characteristics that

make its manipulation in any predictable fashion a difficult task. As part of the hydrologic

cycle, ground water cannot be managed separately. Any management scheme must recognize that it is inextricably linked to the surface

water resources of a region. Those regions that

have overcommitted their surface water resources, either from the quantity or quality

standpoint, cannot depend on a supply of

‘‘new’ water from ground water supplies.

Where surface water supplies are in short supply, it is likely renewable ground water supplies will also be in short supply. Similarly, in

the Western United States, those areas with

surface water supplies in excess of present requirements have ground water supplies that appear to be recharging naturally at rates at least

equal to withdrawal.

Ground water is more diffuse than surface

water. Legal and social practices in the past

have generally treated ground water as if it

existed in discrete underground bodies or

streams. In fact, it is widely and unevenly

distributed throughout most of the surface

rocks of any given region. This characteristic

means that the economic costs of ground water

development for benefits received will be much

higher than for development of the more concentrated surface water bodies.

Technologies designed to affect either the

availability or quality of ground water generally

must be applied at individual water wells.

Thus, they are much more site-specific than are

most other water-related technologies discussed in this assessment. This creates a

number of unique problems in assessing the

nature and degree of potential threats to the

resource. Considerable information concerning local geology, recharge conditions, type of

well construction, and the well’s intended use

is required before these technologies can be

used with confidence. Discussion of problems

involving more than a single water well involves the extrapolation of well data, using assumptions concerning variations in geology,

climate, and other environmental controls.

While there will generally be less disagreement

among hydrogeologists concerning some of

these assumptions and extrapolation techniques, the nonhydrologist may often be at a

loss to assess the conclusions accurately.

Complex ground water models have been developed over the past two decades to aid in the

evaluation of ground water problems. * However, the use of these models has been restricted to a limited number of specialists. For

the most part, ground water information is anecdotal and deals with such local problems as

ground water decline, water-quality deterioration, and land subsidence as a result of the

*For an evaluation of methodologies, see the OTA assessment:

Use of Models for Water Resources Management, Planning, and

Polic.v, 1982.
Ch. X—Technologies Affecting Ground Water ● 291

overuse of ground water. Future management

of ground water resources probably will involve the use of such computer simulation

models because the behavior of the resource

is so complex. This will require the development of a data-collection network for each application site that is much more extensive than

that which now generally exists. Data collection and monitoring is a complex process that

will strain the economic resources of most

communities. It also requires a level of expertise that is rare at levels below that of State or

Federal agencies.

Effects of Ground Water Overdrafting

Prolonged ground water overdrafting may

lead to one or more undesired results. These

include:

progressive reduction in the total volume

of the available ground and surface water

supply, since these supplies are connected,

development of uneconomic pumping

conditions as depths increase,

degradation of ground water quality,

interference with other water rights as

drawdown affects other parts of the

aquifer, and

land subsidence caused by lowered ground

water levels.

The technologies to compensate for these effects are limited. There arc no known technologies, for example, to recover water storage

space lost by land subsidence or to improve

degraded water in aquifers.

It is estimated that ground water overdrafting is occurring in each of the nine major water

resources regions of the Western United States

(15) (table 75, fig. 68). The extent of this overdrafting, and the ability of affected aquifers to

recover in a reasonable time period if present

demands are diminished varies widely among

these regions. This variation results from the

highly complex and variable geology and climate of the region. As early as 1949, Warne

<<

. . . drew attention t o ‘trouble spots’

throughout the United States where heavy draft

upon the water-bearing formations has resulted

in the depletion of the underground water at

a rapid rate. ” According to Warne, in 1949

these areas of concern already included “the

Central Valley of California, the West Basin

southwest of Los Angeles, the High Plains of

Texas, south of Amarillo . . . and elsewhere”

(3). States where ground water withdrawals are

a high percentage of total water use, it can be

assumed that problems of sustainability will

develop with time.

By definition, ground water overdrafting is

nonsustainable, since the water resource is being used at a rate greater than it becomes available. According to the WRC estimates of

ground water supply and use in the Western

United States, the present (1975) ground water

overdraft represents 12 percent of the total

water withdrawn from all sources in the Western region and is some 20 million acre-ft annually (15). This is almost 11/2 times the annual

flow of the Colorado River.

Serious social disruptions may result when

economic, social, or environmental systems

develop, based on a limited surface/ground

water supply. Arguments in favor of ground

water mining are commonly economic in

nature. It is argued that water in storage is of

no value unless it is withdrawn. This argument

is valid only to the extent that an infrastructure is not developed based on the limited supplies. As ground water supplies are depleted,

surface water supplies commonly also become

less available. Ground water becomes increasingly expensive to withdraw as water table

levels decline. Ultimately, water must be imported in order to support the water-dependent infrastructure. As economic costs make this

increasingly unfeasible, however, those areas

may suffer some economic decline.

Two recent examples of this sequence are the

Central Arizona Project (CAP) and the Central

Valley Project (CVP) in California. A GAO report estimated that the total cost for these two

projects, designed to replace water originally

mined from local aquifers, would be approximately $5 billion* (197’7 dollars) (13). The

*$I.5 billion for CAP and $3. EI billion for (;J’P
292 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

—-—. — —

Table 75.—Ground Water Mining in the Western United States

The pressure on total water resources of a region Increase as the percentage of ground water mining Increases.

Ground water mining

as a percentage

Region Subregion of annual off stream

number number Name consumption

11

12

13

15

16

17

18

10

03

05

06

07

08

09

10

11

01

02

03

04

05

06

07

01

02

03

04

05

02

03

04

05

01

02

03

01

02

03

04

01

02

03

04

05

07

02

03

05

06

07

MISSOURI . . . . . . . . . . . . . . . . . .

Missouri-Musselshell . . . . . . . . . . . . . . . .

Western Dakotas . . . . . . . . . . . . . . . . . .

Eastern Dakotas . . . . . . . . . . . . . . . . . . . .

North and South Platte . . . . . . . . . . . . .

Niobrara-Platte-Loup . . . . . . . . . . . . . . .

Middle Missouri . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . . . . . . . .

Lower Missouri . . . . . . . . . . . . . . . . . . .

ARKANSAS-WHITE-RED . . . . . . . . . . . . . .

Upper White . . . . . . . . . . . . . . . . . .

Upper Arkansas . . . . . . . . . . . . . . . . . .

Arkansas-Cimmaron b 

. . . . . . . . . . . . . . . .

Lower Arkansas . . . . . . . . . . . . . . . . . . .

Canadian . . . . . . . . . . . . . . . . . . . . .

Red-Washita . . . . . . . . . . . . . . . .

Red-Sulphur. . . . . . . . . . . . . . . . . . . . . . .

TEXAS-GULF . . . . . . . . . . . . . . . . . . . . . .

Sabine-Neches . . . . . . . . . . . . . . . . . . . .

Trinity-Galveston Bay. . . . . . . . . . . . . . . .

Brazes . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Colorado (Texas). . . . . . . . . . . . . . . . . .

Nueces-Texas Coastal . . . . . . . . . . . .

RIO GRANDE . . . . . . . . . . . . . . . . . . . . . . . .

Middle Rio Grande. . . . . . . . . . . . . . . . .

Rio Grande-Pecos. . . . . . . . . . . . . . . . . .

Upper Pecos . . . . . . . . . . . . . . . . . . . . . . .

Lower Rio Grande . . . . . . . . . . . . . . . . .

LOWER COLORADO . . . . . . . . . . . . . . .

Little Colorado . . . . . . . . . . . . . . . . . . . . .

Lower Colorado Main Stem . . . . . . . . .

Gil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GREAT BASIN . . . . . . . . . . . . . . . . . . . . .

Bear-Great Salt Lake . . . . . . . . . . . . . .

Sevier Lake . . . . . . . . . . . . . . . . . . . . . . .

Humboldt-Tonopah Desert . . . . . . . . . . .

Central Lahontan . . . . . . . . . . . . . . . . . . .

PACIFIC NORTHWEST . . . . . . . . . . . . . . .

Clark Fork-Kootenai . . . . . . . . . . . . . . . . .

Upper/Middle Columbia. . . . . . . . . . . .

Upper/Central Snake . . . . . . . . . . . . . . .

Lower Snake . . . . . . . . . . . . . . . . . . . . .

Coast-Lower Columbia . . . . . . . . . . . . . .

Oregon Closed Basin . . . . . . . . . . . .

CALIFORNIA . . . . . . . . . . . . . . . . . . . . . . . . .

Sacramento-Lahontan . . . . . . . . . . . . . . .

San Joaquin-Tulare. . . . . . . . . . . . . . . . .

Central California Coast . . . . . . . . . . . . .

Southern California . . . . . . . . . . . . . . . . .

Lahontan-South. . . . . . . . . . . . . . . . . . . . .

17

1

2

7

13

13

16

41

5

68

2

3

100

2

85

55

1

50

8

19

78

38

26

16

21

46

16

1

53

7

27

61

16

3

60

27

3

5

2

8

4

7

2

2

8

4

10

10

8

43

SOURCE K Frederick and J Hanson, Water for Western Agriculture (Washington, DC: Resources for the Future, 1962) (Original

source U.S Water Resources Council, The Nation’s Water Resources 1975-2000 (Washington, DC US Govern.

ment Printing Office, 1978), vol 3, app II, table II-6
Ch. X—Technologies Affecting Ground Water ● 293

-—— ——

Figure 68.— Regions of Ground Water Withdrawal in

Excess of Recharge

According to a recent study by Resources for

the Future* (4) ground water mining has two

adverse effects on water costs. First is the increased pumping lift. On a regional or statewide basis, this increase may average not more

than 1 to 3 ft a year, generally signifying an annual increase of 1 or 2 percent. On a farm-byfarm basis, however, there is a great deal of

variation, and an individual irrigator may face

a more rapidly declining water level.

SOURCE J Bredehoeft

West paper presented at Impacts of Limited Water for Agriculture

I n the Arid West AsiIomar Calif., Department of Land, Air, and Water

Resources, University of California Davis 1982

federally supported CAP will include the construction of canals to carry water from the Colorado River to the cities of Tucson and

Phoenix, Ariz. The federally supported CVP is

a large multipurpose project in California, consisting of 19I dams and related water conveyance systems and hydroelectric generating

plants. The CVP's primary purpose is to provide irrigation water to the Sacramento and

San Joaquin Valleys. According to the GAO

Comptroller General:

. . . it appears that the population and economies of the areas (Arizona and California) developed at higher rate than could be supported

by the existing water supplly. Once such developments had taken place, crisis-oriented solutions had to be considered which involved

large expenditures and which required Federal

assistance.

A second effect is the decrease in saturated

thickness as the aquifer is mined. As saturated

thickness declines, so does well yield. Eventually, additional wells and pumps are needed to

maintain the flow. For example, a center-pivot

distribution system requires a minimum well

yield of 600 gallons per minute (gpm).

At lower yields, farmers must either adopt

a new irrigation system requiring fewer gallons

per minute, add to the number of wells, or be

satisfied with less than optimum coverage.

These alternatives tend to increase production

costs or decrease crop yields. In Texas, where

declines in saturated thickness are especially

serious, some farmers have installed eight or

nine smaller pumps, each yielding 75 to 150

gpm, to reach adequate output. On farms with

a center pivot or other sprinkler system, the

decline in the aquifer’s saturated thickness and

its resulting problems may have a greater impact on water costs than do the increased

energy costs resulting from greater pumping

lifts.

In addition to other effects, subsidence** is

often associated with ground water mining, As

the ground water level drops, the bouyancy

provided by the water is removed and the individual grains in unconsolidated aquifers

move closer together, diminishing the ability

of the aquifer to store water and causing the

overlying land surface to sink, While there are

a number of land use activities that may cause

this phenomenon, in the Western United States

ground water mining associated with irrigated

agriculture has produced the bulk of the existing land subsidence problems.

*An independent, nonprofit” (X.(JII[)III1( ,l]],]l~ii~ (]r~,il)iz,]t][)]l.

* *The sink or colla~)~c of thtl lan(l ~(lrf,l( (I>,
294 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands — —- .- . —

The effects of subsidence on agriculture have

been most extensive in those areas where

ground water withdrawal for irrigation is common. For example, water withdrawal in the

San Joaquin Valley of California produced subsidence of up to 20 ft by 1967 over an area of

2,500 square miles during 40 years, The gradual lowering of the land surface damaged expensive water-well casings, irrigation systems,

buildings, and drainage and flood-control

structures, and produced flow direction reversals in irrigation canals. In California’s San

Jacinto Valley, approximately 5,400 square

miles of cropland have subsided at a rate of up

to 1.2 ft/per year since measurements began in

1935, In some portions of the Valley, it has

reached a total of 28 ft (12). Costs are high for

repairing such damage, In California’s Santa

Clara Valley, subsidence costs during the same

period were estimated at $15 million to $20

million.

A similar situation exists in the Texas-Gulf

aquifers, where water withdrawals have been

primarily for industrial and urban uses. Agricultural lands have been adversely affected by

the resulting subsidence, During a 26-year period, 1943 to 1969, in the Houston area, a region some 15 miles in diameter suffered a 2-ft

lowering of the surface. An area of about 60

miles, much of it rural land, suffered at least

6 inches of subsidence during the same period.

These depressed land surfaces act as closed

basins during heavy, hurricane-associated rainfall and thus periodically limit the land’s

usefulness for crop production.

CONCLUSIONS

Ground water use in the Western United

States almost tripled between 1950 and 1975,

and the percentage of the total water withdrawn in the region nearly doubled. Much of

this increase has been made possible by technologies that have permitted the overdraft, or

‘‘mining, ’ of ground water, leading to the

noticeable depletion of the resource in many

areas. Attempts to recharge these ground water

supplies artificially depend on a water surplus

during at least some part of each year to use

for recharge, In many of the areas most affected by ground water overdraft, the total

available renewable water resources are being

completely consumed each year.

Water quality is highly variable among the

major ground-water resource regions of the

Western United States, varying with groundwater recharge rates, rock chemistry, and human waste-disposal practices. With the exception of portions of the Pacific Northwest and

eastern Texas, the ground water of the Western

States is moderate to very “hard,” with high

concentrations of calcium and magnesium

salts. When water having high levels of these,

or any other salts, is brought to the surface and

used for irrigation, evaporation losses lead to

increases of soil-salinity levels. Irrigation

return flows, with high levels of dissolved salts

and agricultural chemicals, percolate back into

the ground water, producing a further deterioration of the existing water quality.

Once a ground water aquifer becomes contaminated, relatively little can be done to remove or contain the contaminant. A few technologies have been investigated for dealing

with ground-water contamination problems,

but in general these have been very expensive

to implement and have produced uncertain

results. * Technologies effective against ground

water pollution are those associated with surface and subsurface waste disposal and designed to prevent contaminants from reaching

the aquifer. Better control of toxic and noxious

substances in surface and subsurface waters

will probably remain the only feasible ground

water pollution-control technologies in the

foreseeable future.

While irrigated agriculture has consumed the

largest volumes of ground water in recent dec-

*OTA is currently conducting an assessment on ground water

resources entitled: Technologies To Measure, Monitor, and

Mitigate Ground Wafer Con fifmin(]tion, estimated delivery date

late 1983.
Ch. X—Technologies Affecting Ground Water . 295

-.

ades in the Western United States, the percentage developed for municipal and industrial

uses has become increasingly important. Many

Western cities are now dependent on ground

water. AS ground water resources are degraded

by ground water overdraft or quality largely

caused by irrigated agriculture, the supplies on

which these cities have become dependent also

decline in both quantity and quality. While irrigated lands may be shifted to a use of lower

1 .

2.

3.

4.

5.

6.

7.

8.

value as water levels decline, cities cannot

make this transition so easily. The social costs

of declining water tables and increasing contamination of ground water resources of the

Western United States must be addressed as

both an agricultural and a broader social and

public health problem. Until more understanding has been gained, the most appropriate

ground water technology may be prudent and

conservative water-use management.

CHAPTER X REFERENCES

I]alciwin, I{., and McGuiness, C., A Primer on

(lround M’ater, U.S. Geological Survey, 1963.

Dat’is, G,, I.ofgren, B., and Mack, S., Use o f

Ground Water Reser\roir.? for Storage of Surface Water in the San ]oaquin b’alle~’, Calif.,

U.S. Geological Sur\cy Water Supply Paper

1618, 1964.

Engineers Joint (;ouncil, Principles of a Sound

Na fional kl’a ter f+)ii(;~’, The N’ ational water

Policj Pane] of the Engineers Joint Council,

publisher una~ailablc.

Fre[icri(:k, K., an(i Hanson, J., Water for Western Agriculture (Washington, D. C.: Resources

for the F’uture, 1982).

H i,gh Plains Associates, Six-State High Plains

Oga]ia]a Aquifer Regional Resources Stud~,

Sun]mar~r: A Report to the U.S. Department of

(lon]nler(:c an<] the Iiigh Plains Stud~’ CounCi], July 1982 .

High Plains Underground Water Conservation

District No. 1 and Texas Department of Water

Resources, A Summary of Techniques and

Management Practices for Profitable Water

Conservation on the Texas High Plains, Report

79-oI, Lubbock, Tex., 1979.

National Water Commission, Water Policies

for the Future (Port Washington, N, Y.: Water

Information Center, Inc., 1973], pp. 227-247.

Richter, R. C., and Chun, R. Y. D., “Artificial

Recharge of Groundwater Reservoirs in Cali9.

10.

11.

12.

13.

14.

15.

fornia,” Jour. of the lrrig. Drain. Div., Am. Soc.

Civil Engs., vol. 85, No. IR4, 1959, pp. 1-27.

Schoeller, H,, “Arid Zone Hydrology, Recent

Developments, UNESCO Arid Zone Research, 1959, in R. Ward, Principles of Hydrology (London: McGraw-Hill, 1975), p. 196.

Todd, D,, Ground Water HydroZog~, 2d ed.

(New York: John Wiley & Sons, Inc., 1980).

U.S. Committee on Irrigation, Drainage an(i

Flood Control, International Commission on

Irrigation and Drainage, “Development of

Techniques to Recharge Subterranean Aquifers to Conserve Surplus River Flows in the

united States, ” Symposium of Athens, 1978,

pp. s2-S23.

U.S. Congress, Office of Technology Assessment, Impacts of Technology on U.S, Cropland

and Rangeland Productivity (Washington,

D. C.: U, S. Government Printing Office, OTAF-166, August 1982).

U.S. General Accounting Office, “Ground

Water: An Overview, ” 1977.

U.S. General Accounting Office, Better Monitoring Techniques Are Needed to Assess the

Quality of Rivers and Streams, vol. 1, 1981.

U.S. Water Resources Council, The Nation

Water Resources 1975-2000, 211~ National Water Assessment (Washington, D. C.: U.S. Go\~-

ernment Printing Office, 1978].
Selected Technologies

Affecting Land and

Water Management
Page

The Water Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

The Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

Water Management.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

Water Management by Conjunctive Use.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

Land Use Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

Computers and Information Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327

conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

Chapter XI References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

List of Tables

Table No. Page

76. Comparison of Irrigation, Overland Flow, and

Infiltration-Percolation of Municipal Wastewater . . . . . . . . . . . . . . . . . . . . . . . . . . 306

77. Expected Quality of Treated Water From Land Treatment . . . . . . . . . . . . . . . . . . 308

78. Summary: Issues Surrounding Water Reuse for Irrigation . . . . . . . . . . . . . . . . . . 309

79. Crop Yields at Various Levels of Application of Wastewater,

Pennsylvania State University . .............................0.. . . . . . . . . . 309

80. Conjunctive Use of Surface Water and Ground Water Resources . . . . . . . . . . . . 311

81. Examples of Human Substitutions for Biological Processes . . . . . . . . . . . . . . . . . 323

82. Gross Revenue to Western Statesa From Hunting and Fishing Licenses in 1981 325

83. Relationships Between Agriculture Practices and Fish and Wildlife,

Sacramento Basin and Delta-Central Sierra Hydrologic Study Areas . . . . . . . . . . . . 326

List of Figures

Figure No, Page

69. Crop-Management Model for Flexible Cropping . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

70. Sample Crop-Management Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

71. The Wastewater Renovation Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

72. The Major Types of Wastewater Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

73. Summary Information for Using Big Sagebrush in Rangeland Reclamation . . . 316
Chapter XI

Selected Technologies Affecting

Water and Land Management

Continued agricultural productivity of arid

and semiarid lands will require more careful

and integrated management of many resources, including water. Improved water and

land management can help to restore the inherent productivity of many agricultural lands

that suffer from erosion, soil compaction, soil

salinity, or other adverse conditions. In irrigated areas, better water management may

compensate for the decreasing availability of

use of technology and “smart” users when resources become less available. This chapter

highlights an assortment of these lesser known,

and sometimes unconventional, practices for

managing water and land. This discussion is

not all-inclusive, however. Rather, each technology has shown its usefulness i n some locations and may play an increasing role in arid

and semiarid agriculture in the Western United

States.

affordable water which many experts predict,

Management

power and there

technologies rely on brainis no substitute for intelligent

SETTIN6

Most irrigation systems and arid/semiaridland cropping systems developed to manage

water; historically, patterns of agricultural land

use and agricultural practices reflected this

characteristic. Today, the more promising contemporary management schemes show a similar understanding of water in arid/semiarid

lands: the limited absolute amounts of water,

its spatial and temporal unevenness, its susceptibility to effectite exhaustion, and the interconnected nature of different water resources.

As an example, some areas are using the watershed (the fundamental hydrologic unit) as a

political management unit. In other locations,

individuals recognize that it is difficult to affect one hydrologic: component without altering others and have linked the use of ground

and surface waters.

The use and management of water, then, is

becoming more attuned to economic and natural resource conditions. For some regions,

however, the most precise use of water requires

more careful land management rather than water management per se. Rangeland agriculture,

for example, involves managing plants and animals to provide optimal production from existing precipitation. Although the amount of

water involved is small compared to irrigated

agriculture, the land areas are vast and agricultural production from these regions is significant nationally.

299
— . —

300 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Water

THE

Management

Flexible Cropping

INTRODUCTION

—

In much of the semiarid region, low precipitation limits dryland crop production to some

type of crop-fallow (noncropping season) system. Traditionally, farmers in the low rainfall

areas of the northern and central Great Plains

have strictly practiced this alternate-year rotation. In the slightly higher rainfall regions of

the southern Great Plains, more intense rotations such as two crops every 3 years or annual cropping have been possible.

TECHNOL0GIES

Dryland farmers in recent years have practiced methods of crop production that improve

water storage during the fallow period, such

as stubble mulch tillage and conservation tillage (ch. VIII). These technologies have helped

increase the amount of water stored during the

fallow period. Although there have been tradeoffs, for example, in weed control, this higher

level of soil water is sufficient in some cases

to allow farmers to grow crops each year,

Flexible cropping is an outgrowth of this development. In this system, a crop is planted

when stored soil water and predicted rainfall

are favorable for a satisfactory yield. When

Box X.—”Best Management Practices”

The importance of management practices for achieving various resource objectives has been

long recognized. Conservation plans initiated by the Soil Conservation Service during the 1930’s,

for example, recommended certain management practices for controlling soil erosion. “Best management practices” for controlling nonpoint sources of water pollution were formally recognized in

the Federal Water Pollution Control Act (FWPCA) of 1972 (Public Law 92-500) as amended by the

Clean Water Act of 1977. States were instructed to develop and implement “best management practices” to reduce this type of pollution. The actual “best” practices were not specified in the legislation nor in subsequent regulations issued by EPA.

USDA has remained involved with the original conservation plans as well as more recent programs. The Clean Water Act authorized USDA to provide technical and financial assistance to

farmers and ranchers for adoption of FWPCA’s best management practices. While the program

has moved slowly, it has spurred recognition that combinations of practices applied at the watershed level are most likely to meet multiple objectives: water conservation, erosion control, clean

air, sustained food and fiber production, wildlife habitat, and recreational lands.

Computerized agricultural models make the evaluation of management packages simple and

effective. For example, the long-term effects of weather and the implementation of new tillage practices can be tested locally and regionally before investments are made. A variety of agricultural

models are available for these and related purposes. These include: EPIC (Erosion Productivity

Impact Calculation), CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management

Systems), and SWAM (Small Watershed Model).

While technology exists for evaluating management practices, it has not been used to prepare

integrated-management packages for farmers. Some people believe that an adoption bottleneck

has resulted. Debate continues regarding who (i.e., public or private, Federal or non-Federal groups)

should be responsible for putting together management packages. It is unlikely, however, that

USDA’s Agricultural Research Service (ARS) will assume major responsibility. The portion of the

ARS budget allocated to integration of agricultural systems is expected to increase from 2 percent

in 1982 to only 3 percent in 1990.

SOURCE: U.S. Depafiment of Agriculture, Agricultural Research Service, “Agricultural Research Program Plan, &Year Implementation Plan, 19w19QIY’ (Washington,

D. C.: U.S. Government Printing Office, 1983).
-—

Ch. XI—Selected Technologies Affecting Water and Land Management ● 301 —

crop prospects are not favorable, no crop is

planted, and a field is left fallow to store additional soil water.

ASSESSMENT

Flexible cropping systems were developed in

the last few years for use in the northern Great

Plains, Such systems have wide potential application throughout the Great Plains, but

detailed procedures have yet to be developed

for their use.

Success of a flexible cropping system requires a combination of preplanning, in-season,

and postharvest practices. Before planting, a

farmer assesses root-zone water-supply required for planting time and determines predicted seasonal precipitation for the growing

season. Soil characteristics, crop-water requirements, and depth of rooting for different crops

are also considered. If a farmer decides that

soil moisture and predicted precipitation are

sufficient, tillage operations are timed to maximize the water available to the crop, Fertilizer

is applied to stimulate root growth during the

growing season, Weed control and snow management are used after harvest to collect precipitation for the next growing season.

It is difficult for an individual farmer to evaluate all of these factors, and thus computerized

management guides and users’ manuals have

been developed. In Montana, for example,

these materials help farmers decide the best

cropping and soil management options for

wheat, barley, oats, and safflower based on

stored soil water and expected growing season

precipitation (figs. 69 and 70),

Besides making more systematic and optimal

use of stored soil-water supplies and growing

season precipitation, research indicates that

the flexible cropping system may prevent the

formation of saline seeps (ch. VIII), since soil

water is used before it moves below the root

zone.

Many of the limitations associated with flexible cropping systems are similar to those experienced with other water-conservation technologies, For example, if plant-barrier systems

are used to trap winter snow. weeds mav inFigure 69.—Crop-Management Model for Flexible

Cropping

This model, developed in Montana, depicts grain yield as a

function of water supply crop variety weeds fertility plant

Ing date and rotation. Management decisions and crop information are then provided to the user, who types responses to

questions asked by the computer

Water

module

Crop selection and rotation

I

crease. If conservation tillage is employed,

managers may have difficulty seeding crops

into the resultant residue. Where snow is collected, water might not filter properly into

frozen soil.

Flexible cropping systems also have a unique

set of management limitations. Crop rotations

L are a highly effective way to avoid weed, in-
302 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— —

Figure 70.—Sample Crop-Management Worksheet

SOURCE P O Kresge and A D Halvorson, Fexcrop User's Manual

Computer Assisted Dryland Crop Management Montana State

University Cooperative Extension Service Bulletin 1214. Bozeman.

Mont 1979

sect, and disease buildup, but they have become rare in many regions because of past economic constraints, Therefore, little information

exists to guide farmers in choosing possible

crop rotations. In addition, some crops* are

difficult to work into a flexible cropping system

because they are planted in the fall before most

water is accumulated and total water supplies

are known.

Also, social and economic considerations

currently limit employment of flexible cropping systems. Farmers generally view flexible

cropping as a riskier approach than traditional

crop-fallow practices, one that requires a

higher management commitment. Some farms

may have the labor and time to conduct the intensive soil-water monitoring needed for its application, but total reliance on a flexible cropping system often requires resources (e.g., labor, capitol, and access to agricultural consultants who can assist in monitoring and planning operations) available most readily to large

operations. Federal policies governing crop diversions and set-asides may pose a further barrier to adoption. For example, policies requiring farmers to reduce acreage in order to be

eligible for certain benefits (e. g., commodity

loans and disaster payments) may be in effect

in years when soil-water conditions would

allow full production. In other cases, set-asides

may increase flexibility by allowing installation

of soil- and water-conserving practices without

losing a crop.

Irrigation ScheduIing

INTRODUCTION

Traditionally, many growers schedule irrigation periods by examining crop appearance

and soil-water conditions and judging future

weather. Others time water applications by the

calendar. Still others are forced to schedule irrigations by water delivery rotation systems.

These scheduling procedures give generally

satisfactory results but may not make the most

efficient use of water, maximize crop yields,

or save energy.

The concept of scientific irrigation scheduling” has received much attention in recent

years. It takes into consideration:

c precipitation and evapotranspiration since

the previous irrigation,

c allowable soil-water depletion at the particular growth stage of the crop, and

● expected precipitation and crop-water requirements before the next irrigation.

To assess the need for water application, two

technically sophisticated methods are used:

1) environmental and plant monitoring, and

2) a water budget technique. In the first method, tensiometers, electrical resistance gypsum

* For example, winter wheat.

*The prediction of the time and amount of water required for

the next and future irrigations.
Ch. XI—Selected Technologies Affecting

blocks, or neutron probes are used to measure

soil water (ch. VIII), Plant water stress is inferred through use of infrared thermometers

or pressure chambers, Some of these types of

monitors do not indicate how much irrigation

is needed.

In the water budget method, an alternative

to environmental monitoring, the crop root

zone is visualized as a reservoir of available

water. Water is withdrawn from the root zone

through evaporation or drainage and added

through rainfall and irrigation. If the volume

of water in the root zone—the amount of water

that can be drained without stressing the plant

(or the allowable depletion)–and the depletion

rate (or evapotranspiration) are known, the

date of the next irrigation can be predicted.

Coupled with accurate weather forecasts, this

method allows for accurate irrigation scheduling.

ASSESSMENT

Irrigation scheduling services (ISS) are provided to about 1 million acres in the Western

United States by Federal and State agencies

and private consultants (1 3). Most services are

based on computer predictions of time and

amount of irrigation.

Several advantages of irrigation scheduling

services have been noted by researchers. Limited information indicates that crop yields with

irrigation scheduling can be increased by an

average of 10 to 30 percent primarily a result

of proper timing and sufficient water application although other research has been unable

to document significant increases. Scheduling

may reduce the number of irrigations per season by making maximum use of soil water and

rainfall, It may also help to reduce pollution

of ground water because less excess water is

percolated through the soil. In areas where

electricity is used for pumping irrigation water,

irrigation scheduling may also help manage

peak electrical loads. Moreover, because plant

environmental conditions are better known,

this technology permits managers to plan water

rotations among fields, pesticide applications,

tillage operations, and other activities to minimize crop stress and yield reductions.

Water and Land Management 303

A number of technical and social factors affect the adoption of irrigation scheduling. First,

the effectiveness of the system depends on the

total water application and measurement system, including delivery, application, and irrigation. Before scheduling can be implemented,

each of these systems should be evaluated to

determine capacity, needs, flexibility, and limitations. Surface water delivery systems to the

farm in some areas are fixed and may not be

adapted to scheduling techniques based on

crop-water needs because of the short notice

involved (ch. VII).

Second, field verification of computer predictions about environmental conditions is necessary because of site-specific variability in the

depth of water applied at each irrigation, the

crop rooting depth, soil water storage capacity, allowable depletions, effective rainfall, and

crop evapotranspiration. These field checks require competent and trained personnel who

can communicate effectively with growers. For

example, the Bureau of Reclamation has developed an irrigation management service program to help irrigators schedule water deliveries and application. Private agricultural consultants have also developed scheduling services, These dual efforts raise questions about

the government and private role in onfarm water management (19).

Third, irrigation scheduling services are

adopted when definite economic benefits can

be readily identified by the grower, since these

services are costly and beyond the means of

many farmers. Inexpensive and readily available water supplies reduce the incentive to implement scheduling. As discussed in chapter

V, water law may often inhibit farmers from

conserving irrigation water onsite since the

water “saved” does not become available for

other uses on the same farm. Again, the shortterm economic incentive for adopting the technology may not be adequate, now, but this situation may change rapidly if water costs reflect

more closely replacement value of water,

Fourth, there is general skepticism that yields

can be improved by altering irrigation practices. Scheduling services can increase net income to growers to the extent that the level of
304 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— - — —

Box Y.—Water Management in Israel

Israel has limited freshwater supplies but a rapidly growing population. Consequently, watermanagement strategies during the 1980’s have shifted from development of new supplies to management of water demand. Nationalized water resources, a national supply system, and elaborate programs of technical assistance to water users are important components of this approach. These

arrangements were possible in part because Israel is a small country and neither farm groups nor

water-rights holders existed to oppose their initiation.

Several methods are used to manage water demand: metering, pricing, and allocation. All water

users are metered and receive annual licenses for ground water, runoff, and sewage effluents. Water

prices are adjusted nationally, and larger water users pay higher prices. Water costs are high, reflecting the true scarcity of the resource. Each farm is allocated its water annually, an allocation

which may be decreased the following year.

As a result of these policies, Israelis a leader in several water-use technologies. These include

wastewater reuse, use of brackish water, and specialized irrigation systems. A close-working relationship between researchers and farmers has also ensured that research results are quickly adopted

and often cooperative groups of farmers manufacture new instruments themselves.

SOURCE: U.S. Congress, Office of Technology Assessment, “Water and Agriculture in Arid Lands: selected Foreign Experience-A Background Paper” (Washington,

D.C.: U.S. Government Printing Office, OTA-BP-F-2O, May 1983).

some production input is decreased, the quality

of the crop is increased, or yields are increased.

Among those who provide scheduling services,

there may be an overemphasis on the degree

to which yields can be improved or irrigation

can be reduced.

In sum, irrigation scheduling is a necessary

but incomplete management tool for increasing irrigation efficiencies. It can help to conserve water when precise control is available

throughout the water distribution system.

Wastewater Reuse

INTRODUCTION

Wastewater reuse, defined as the use of land

to renovate sewage effluent from municipal or

industrial sources, is receiving increased attention as a possible way to augment irrigation water supplies and to reduce the water pollution

that might otherwise occur if such wastewater

were released directly to waterways. Those

who advocate wastewater reuse consider that

wastewater and the nutrients it contains are

resources rather than refuse. Wastewater provides water and nutrients to plants, In return,

biological and chemical processes that occur

in the soil, micro-organisms, and plants are

thought to cleanse the wastewater, According

to supporters of this practice, renovated, safe

water may then percolate downward to recharge the ground water reservoir or be discharged directly to surface water (fig. 71).

The idea of using land to treat wastewater

is not new. Parker (22) notes that “treatment

and disposal of sewage by land extensive

schemes of irrigation is the oldest form of the

modern methods of purification, ” These methods dominated U.S. municipal sewage-treatment systems until the early 20th century, but

gradually diminished in importance as metropolitan areas expanded, large expanses of land

adjacent to urban areas became limited, and

concerns grew about possible public health and

water-quality effects. Sewage treatments that

used less land were developed as well.

Since the early 1970’s, interest in land application technologies has revived, In part, this

interest reflects a greater public awareness of

the costs of treatment to meet health standards

and of potential pollution and degradation

caused by the discharge of partially treated

wastes into waterways. It also reflects concerns

about the growing scarcity of unallocated surface water supplies and rates of ground water

depletion, especially in the West. Finally, Fed-
—

Ch. Xl—Selected Technologies Affecting Water and Land Management ● 305

— —— —-—

SOURCE William E Sopper “Surface Application of Sewage Effluent, ” Planning the Uses and Management of Land, Marvin T Beatty, et al (eds ) (Madison, Wis.: American

Society of Agronomy, 1979), pp 633-663 (No 21 in the series Agronomy)

eral actions—e.g., passage of the Water Pollution Control Act of 1972 (Public Law 92-500)–

have stimulated interest in reuse technologies

to balance treatment costs.

Wastewater Treatment Methods

Wastewater contains two major categories of

contaminants: biological and chemical. Biological contaminants include bacterial or viral

pathogens and intestinal parasites. Chemical

contaminants include substances such as nitrates, sodium, heavy metals (e. g., cadmium,

lead, and zinc), oil, grease, and pesticides,

Levels of treatment generally recognized for

wastewater are primary, secondary, and tertiary. This classification is based on the removal of suspended solids and on the reduction of

biochemical oxygen demand (BOI))-i.e., the

oxygen needed to meet metabolic needs of aerobic micro-organisms in water containing organic matter. Primary treatment consists of

mechanical and physical removal of suspended
306. Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

solids. This process is estimated to remove approximately 35 percent of the BOD and 60 percent of the suspended solids in raw sewage water (26).

Secondary treatment introduces biological

processes—e.g., activated sludge or trickling

filters—to remove much of the remaining suspended solids and organic matter. Secondary

treatment will remove from 80 to 95 percent

of the BOD and suspended solids (26).

Tertiary, or advanced wastewater, treatment

is used after primary and secondary treatments

to reduce BOD further, remove suspended solids, lower nutrient concentrations, and improve the effectiveness and reliability of disinfection. Land application of wastewater is

considered one method of tertiary treatment

along with others such as chemical coagulation, clarification, filtration, activated carbon

treatment, and reverse osmosis.

Advanced wastewater treatment by land application can be achieved in a variety of ways,

depending on the goal of the treatment, the

composition of wastewater, and characteristics

of the waste site. The three most commonly

used methods for land application are slow-rate

irrigation, overland flow, and rapid infiltrationpercolation, Table 76 compares the three methods by use objectives.

Slow-rate irrigation (fig, 72-A) is probably the

method used most often and with most potential for agricultural use. In this process, wastewater is applied to the soil surface by a fixed

or moving sprinkler system or by surface irrigation. Water application rates are generally

low and are largely determined by climate, soil,

and the water and nutrient needs of the crops.

Treatment proceeds as vegetation and soil

micro-organisms act to remove and alter wastewater as it percolates through the soil.

Overland flow reuse systems (fig. 72-B) also

rely on a vegetative cover to effect waste treatment but differ from slow-rate methods

because crop production is usually not a major objective, In this process, wastewater is applied over the upper parts of vegetated terraces

and allowed to flow in a thin sheet down the

relatively impermeable surface to runoff collection ditches, Only small amounts of wastewater infiltrate into the soil or percolate to the

ground water. Renovated water that is collected may be reused or discharged directly to

surface water. Treatment occurs by physical,

chemical, and biological means.

Table 76.—Comparison of Irrigation, Overland Flow, and

Infiltration-Percolation of Municipal Wastewater

Type of approach

Overland lnfiltrationObjective Irrigation flow percolation

Use as a treatment process with a recovery of ‘-

renovated water a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0-70 ”/0 50-800/o Up to 970/0

recovery recovery recovery

Use for treatment beyond secondary:

1. For BODb and suspended solids removal . . . . . . . . . . . 98 + 0

/0 92 + % 85-990/o

2. For N removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 + %c 70-900/0 0-50 ”/0

3. For P removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80-99°/0 40-800/o 60-950/o

Use to grow crops for sale. . . . . . . . . . . . . . . . . . . . . . . . . . . . Excellent Fair Poor

Use as direct recycle to the land . . . . . . . . . . . . . . . . . . . . . Complete Partial Complete

Use to recharge ground water . . . . . . . . . . . . . . . . . . . . . . . . . 0-70 ”/0 0-10 ”/0 up to 97 ”/0

Use in cold climates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fair d d Excellent

aPercentage of applied water recovered depends on recovery technique and the climate

bBOD = Biochemical oxygen demand

CDependent on crop uptake

dConflicting data—woods Irrigation acceptable, cropland irrigation marginal

‘Insufficient data

SOURCE William E Sopper, “Surface Application of Sewage Effluent,” Planning the Uses and Management of Land, Marvin

T Beatty, et al (eds ) (Madison, Wis American Society of Agronomy, 1977), pp 633663 (No 21 in the series Agronomy)

(Original source U S Environmental Protection Agency, “Process Design Manual for Land Treatment of Municipal

Wastewater, ” EPA 62511-77-008 (Washington, D C , 1977).
.

Ch. XI—Selected Technologies Affecting Water and Land Management . 307

— . . . .

Figure 72.—The Major Types of

Wastewater Treatment

A. Slow-rate irrigation

Wastewater IS applied to the soil surface and allowed to

percolate downward Treatment proceeds as soil, vegetation,

and soil micro-organisms remove nutrients and suspended

solid material.

B. Overland flow reuse

Wastewater IS applied to a sloping surface and allowed to

flow over the soil surface to runoff collection ditches Treatment IS a result of physical, chemical, and biological

processes

C. Rapid-infiltration percolation

Wastewater IS applied by flooding or sprinkling to highly

permeable soils in basins. As the wastewater percolates Into

the soil renovation occurs

Evaporation

SOURCE William E Sopper “Surface Application of Sewage Effluent,” Planning

the Uses and Management of Land, Marvin T Beatty, et al. (eds.)

(Madison, Wis. American Society of Agronomy, 1979), pp. 633-663. (No.

21 in the series Agronomy )

Rapid infiltration-percolation, the third method, uses less land area to effect treatment than

do the other two methods. The main objective

in this system is ground water recharge (fig.

72-C). Wastewater is applied to highly permeable soils in basins by flooding or sprinkling.

The basins may or may not be vegetated. Renovation occurs through natural processes in the

soil as water percolates downward.

The degree of success for wastewater treatment varies with the type of method used to

apply wastes, Table 77 shows expected treatment performance for these three processes.

ASSESSMENT

Municipal wastewater is now used for irrigation, However, information on the number of

communities that use land treatment for sewage renovation and the number of individuals

who use wastewater to irrigate agricultural

crops is inexact, because funding for these systems may be through the Federal Government,

industry, or private sources, With Federal funding, estimates are that approximately 1,000

municipalities use land application to treat

wastes (31). Unpublished data from the U.S.

Geological Survey (USGS) indicate that in 1980,

0,5 billion gal/day of effluent were used for irrigation compared to 290 billion gal/day of

fresh surface water and 88 billion gal/day of

fresh ground water.

Some communities use municipal wastewater for irrigation for parks, golf courses, and

greenbelts and Federal and State guidelines

have been developed for its application (e.g.,

22,36). In California, for example, irrigation return flows of relatively good quality are applied

to wetland areas to maintain natural vegetation. These areas are then used for cattle grazing in summer and hunting in the fall. Chemical wastes from potato processing plants have

also been used for irrigation. In spite of these

signs of acceptance, widespread adoption of

reuse systems for most agricultural crops is

hindered by numerous biological, social, economic, and legal questions and a lack of longterm research on the subject. Chapter IV discusses some of the more serious public health

questions that still need answers before fullscale programs should be adopted. Table 78

presents a summary of issue areas that require

resolution.

Three examples illustrate the complexity of

these issues. First, regarding the question of
308 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Table 77.—Expected Quality of Treated Water From Land Treatment (mg/liter)

Slow rate’ Rapid infiltration Overland flowc

Constituent ‘Average Maximum ‘Average Maximum Average Maximum

BOD ... . . . . . . . . . . . . . . . . . . . <2 <5 2 <5 10 <15

Suspended solids. ., . . <1 <5 2 <5 10 <20

Ammonia nitrogen as N . . <0.5 <2 0.5 <2 0.8 <2

Total nitrogen as N . . . . 3 <8 10 <20 3 <5

Total phosphorus as P . . . . . <0.1 <0.3 1 <5 4 <6 —.

aPercolation of primary or secondary effluent through 1.5 m (5 ft) of soiI.

bPercolation of primary or secondary effluent through 45 m (15 ft) of soil

C

Runoff of municipal wastewater over about 45 m (150 ft) of slope

SOURCE William E Sopper Surface Application of Sewage Effluent, ” Planning the Uses and Management, of Land, Marvin

T Beatty et al (eds ) (Madison, Wis. American Society of Agronomy, 1977), pp 633-663 (No 21 in the series of

Agronomy) (Original source U S Environmental Protect Ion Agency “Process Design Manual for Land Treatment

of Muntcipal Wastewater, EPA 62511-77008 (Washington, D C 1977 )

land productivity with reclaimed water, data

indicate that the yields of crops irrigated with

wastewater usually increase or remain the

same (9,26), but crops seem to vary in their tolerance to wastewater application (table 79). For

example, research in Hawaii on sugarcane

tested the dilution of wastewater required for

optimal sugar yield (18). Five treatments for the

2-year cane cycle were tested: 1) conventional

irrigation water, 2) 12.5-percent effluent diluted

with irrigation water, 3) 25-percent sewage water, 4) 50-percent effluent diluted with ditch

water, and 5) effluent the first year and irrigation water the second year. Scientists found

that sugar yields for wastewater concentrations

up to 25 percent, or for wastewater the first

year and irrigation water the second year, were

equal to those from conventional irrigation supplies. When wastewater concentrations increased to 50 percent, however, sugar yields

and juice quality declined significantly. The

researchers concluded that chlorinated, secondarily treated sewage effluent with nitrogen

concentrations could be used in furrow irrigation for the 2-year crop cycle of sugarcane if

wastewater were diluted with freshwater so

that the concentration of effluent was 25 percent or less. They cautioned, however, that effluent quality must be constantly monitored for

nitrogen content, pesticides, heavy metals, and

pathogenic viruses. Such substances in the

soils or waterbodies could prove difficult, if not

impossible, to eliminate (chs. IV and X). In addition, field workers were warned to practice

careful sanitation and personal hygiene to protect against infection.

A second illustration provides a sample of

the economic questions that surround application of wastewater for irrigation. Although effluent was generally recognized as a valuable

resource for water and nutrients, few farmers

actually measured the fertilizer value of the

water. Similarly, those in local governments

responsible for the operation of reuse systems

acknowledged the economic value of the effluent but had not established procedures to

charge landowners or farm operators for the

value that they received. Instead, they took the

view that landowners performed a service in

disposal of municipal waste effluent.

Third, with regard to social concerns, public

reaction may be an obstacle to wastewater reuse. A survey of selected California communities indicated that respondents favored water

treatment options that protected public health,

enhanced the environment, and conserved

scarce water (5). However, use of reclaimed

water for ground water recharge and drinking

supplies was perceived as a threat to human

health. Effluent used for industrial purposes or

for irrigation of animal feed and fiber crops

was considered to be an acceptable practice (6).

The inconsistency arises when contaminants

from effluent reach the ground water secondarily, as the result of its use in industry or

irrigation.

Wastewater reuse has been adopted by relatively few communities and farmers in the

United States. It can potentially supplement irrigation water supplies and reduce reliance on

added fertilizer, but generates many questions
Ch. Xl—Selected Technologies Affecting Water and Land Management 309

Table 78.—Summary: Issues Surrounding

Water Reuse for Irrigation

Resource issues: ‘-

1. Effluent quality:

—Nutrient conten t

—Heavy metal conten t

—Pathogen conten t

2. Soil productivity”

—Salt buildu p

—Toxicity buildu p

—Viral contaminatio n

—Physical degradatio n

3. Crop production:

— Fertilizer and water requirements

—Crop growth and yield s

—Crop uptake of nutrient s

—Crop uptake of toxics and pathogen s

4 Animal health.

—Animal uptake of nutrients

—Animal transmission of pathogens to huma n

consumers

5. Ground water quality

—Path of water to water table

—Quality of water reaching ground water

6. Air quality (with sprinkler irrigation)

—Health effects for workers and nearby resident s

—Odor consideration s

Social and economic issues:

1. Human health effects:

—Contact with effluent by farmworkers

–Contact with plant and animal products by

consumers

2 Social factors

—Public attitudes toward application

—Public attitudes by consumers of products

—Attitudes of nearby residents

3. Economic considerations

—Water pricing

—Transportation costs

—Subsidies for those who use water

— Facilities for water storage

—Value in alternate uses

—Type of material contained in water

Institutional issues:

1. Water-treatment facilities

—Adequacy and reliability of treatment prior to

application

—Adequacy of storage facilities during periods of

nonapplication

2. Monitoring

—Need for monitoring air, effluent, ground water, crop,

and soil quality

3 Legal issues

—Ownership and sale of water

—Water rights

—Liability for damages

—Responsibility for monitoring

—Guidelines for water reuse (e. g., crops to be grown,

amount of water to be applied)

—Effect on downstream users (third parties), if water

previously was part of return flows

SOURCE William H. Bruvold Agricultural Use of Reclaimed Water unpublished

paper prepared for National Science Foundation January 1982 Off Ice

of Technology Assessment, 1982

Table 79.—Crop Yields at Various Levels of

Application of Wastewater, Pennsylvania

State University

— ——.

Wastewater Application Rates.

inches per weeka

Crop O

b

1,0 2.0

(bushels/acre)

Wheat . . . . . . ... 48 45 54

Corn ., . . . . ... 73 103 105

Oats. ., ... ... .. ...82 113 88

(tons/acre)

Alfalfa . ... . . 22 3.7 51

Red clover ., ... . . . . 2,4 4.9 4,6

Corn stover ... ... 3.6 7.3 8.5

Corn silage ... . . . 4.3 6.4 6,0

Reed canary grass ., . . 1.4 — 5.0

aMetric units in original document have been converted to English units.

bControl areas received commercial fertilizer ranging from 10 tons/acre of

0-20.20 for oats to 40 tons/acre of 10-1010 for corn

SOURCE William E Sopper ‘Surface Application of Sewage Effluent Planning

the Uses and Management of Land Marvin T Beatty et al (eds) 

(Madison, Wis American Society of Agronomy 1977) pp 633-663 (No

21 in the series Agronomy) (Original source U S Environmental Pro

tection Agency, ‘Process Design Manual for Land Treatment of

Municipal Wastewater, ” EPA 625/1-77-008 (Washington D C 1977) )

on long-term impacts for soil and water quality and, ultimately, public health. Wider application of reuse systems will require careful planning and monitoring by municipalities and irrigators. The costs and danger of handling

wastewater will have to be balanced with economic benefits of its reuse. In addition, when

applied on a massive scale, questions are raised

about the impacts of this water shift on other

aspects of the hydrologic cycle, especiall y

stream flow, if the treated water has previous-

}, been part of return flows. Moreover, legal

considerations for downstream users may be

complex. Much research has been done on this

topic, but additional long-term research on the

effects of these systems on crops, soils, ground

water, and human and animal consumers is

needed. ,

Water Management by Conjunctive Use

INTRODUCTION

The concept of conjunctive use is predicated

on shifts between surface and ground water

use and storage, During periods of aboveaverage precipitation, or seasons of aboveaverage runoff, surface water would be used

to the maximum extent possible to fulfill various water requirements. Any surplus water
310 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands — .—

would be used to recharge ground water supplies and raise ground-water levels. During dry

periods, surface water supplies would be supplemented by ground water reserves.

ASSESSMENT

Whether conjunctive management of a basin’s water is technically practical depends on

local geology and the extent to which ground

water resources are manageable over a range

of water levels. There must be space to store

recharge water, there must be water in storage

when and where it is needed, and there must

be the physical facilities and energy available

to transport surface and ground water.

Management by conjunctive use requires

careful planning to optimize the use of the

available surface and ground water resources.

Detailed, site-specific engineering and economic analyses are needed to determine optimal

mixes of surface and ground water storage.

A conjunctive use management approach requires more information than is commonly

necessary for the use of either surface or

ground water resources separately. In the most

general terms, these information requirements

include detailed data on surface and ground

water resources, the geologic conditions of the

basin, interconnections of surface and ground

water supplies, water-distribution systems, historical and projected water-use patterns, and

wastewater disposal practices.

Commonly, except perhaps in the simplest

situation, mathematical models are required to

describe the reaction of the ground water reserves to fluctuations in natural and artificial

recharge and to varying pumping rates. Such

models are available, but they vary widely in

capability and limitations and must be used

carefully. State governments indicate the desire

for more resource models, while the Federal

Government needs to better coordinate the use

of models among various agencies (32),

Ultimately, decisions concerning the feasibility of conjunctive use management of water

resources must also include an assessment of

the relative economic benefits of constructing

additional surface storage facilities, the increased complexity of conjunctive management approaches, and the cost of energy to

pump water from aquifers. Because each project will be unique, no universal rules exist

governing the economics of this approach to

water management. Some of the advantages

and disadvantages are listed in table 80.

Enclosures for Plants and Fish

INTRODUCTION

Greenhouses are commonly used in the

United States to grow horticultural products

such as flowers and houseplants. In Europe,

enclosures are used also for crops primarily of

very high economic value, such as table vegetables. In the Middle East and Asia raising fish

in enclosures is an ancient applied science.

Aquiculture in various forms provides over 40

percent of total fisheries production in some

countries but only about 2 percent of total

fisheries products (7).

Many features of arid and semiarid lands

make them especially suitable for growing

plants or fish in enclosures: solar energy is

abundant, growing seasons are long, and winters are often mild, Typically, the efficiency

with which water is used is very high, and intensive management allows for the most efficient use of other substances such as fertilizers

and pesticides.

Plant and fish enclosures vary widely in

scale. Some are major corporate enterprises requiring large investments to initiate. Others are

suitable for production of a few items for

household use and local sales.

ASSESSMENT

Experiments around the world with highly

sophisticated systems show that crop yield in

controlled environments is several times that

of field-grown crops. For example, enclosures

in Mexico and Abu Dhabi yielded almost 2 0

different fruits and vegetables at production

levels often several times higher than fieldgrown equivalents with about one-third the use

of water and significantly shorter growing seasons.
—

Ch. XI—Selected Technologies Affecting Water and Land — — —

Table 80.—Conjuctive Use of Surface Water and Ground Water Resources

Management . 311

—

Advantages Disadvantages —.

1. Greater water conservation 1.

2. Smaller surface storage 2.

3. Smaller surface distribution system 3.

4. Smaller drainage system 4.

5. Reduced canal lining 5.

6. Greater flood control 6.

7. Ready integration with existing development 7.

8. Facilitated stage development 8.

9. Smaller evapotranspiration losses

10. Greater control over outflow

11. Improvement of power load and pumping plant use

factors

12. Less danger from dam failure

13. Reduction in weed seed distribution

14. Better timing of water distribution

Less hydroelectric power

Greater power consumption

Deceased pumping efficiency

Greater water salinity

More complex project operation

More difficult cost allocation

Artificial recharge is required

Danger of land subsidence

SOURCE D K Todd, Groundwater Hydrology, 2d ed (New York John Wiley & Sons, 1980) (Original source F B Clendenen,

Economic Utilization of Ground ‘Water and Surface Water Storage Reservoirs, ” presentation to American Society

of CiviI Engineers, San Diego. Calif , February 1955 )

Photo credit Food and Agriculture Organization — U. Pizzi

Many types of plant enclosures exist. These plastic tunnels in Malta, protect horticultural crops,

such as grapes, vegetables, and flowers
312 “ Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

These results are possible because the systems are completely or nearly closed, humidity remains high, and irrigation water is recycled. Enclosures also insulate the grower

from the unpredictable climate of arid and

semiarid regions and help stabilize production,

Marketing is also independent of weather, and

it can be timed to take advantage of highest

prices.

Scientists and engineers continue to refine

technical aspects of these structures. In the face

of rising energy costs, systems that use solar

energy appear promising for long-term production. Bettaque (3) described “eco-islands in the

desert” that use solar energy and saltwater to

heat and cool greenhouses while distilling

freshwater. He found that such enclosures use

minimal amounts of fossil fuel energy, have

capital costs comparable to conventional green

houses, and that increased crop yields are possible with little technical sophistication. Similar

Israeli systems use a closed cycle of freshwater

to absorb solar radiation. Practices that may

not be technically possible in open fields, such

as atmospheric enrichment with higher levels

of carbon dioxide, are also being attempted in

enclosures (24).

Plant enclosures will not produce large

amounts of inexpensive food because the capital costs for large installations are usually high

and operating such enclosures may be laborand energy-intensive. While basic agronomic

crops grow well in enclosures, they are not expected to be grown commercially in this way

in the foreseeable future. The development and

use of less common types of plant enclosures

face many of the same constraints listed be

low for aquiculture. For example, most agricultural experts are not familiar with integrated

plant/fish enclosures or greenhouses, such as

attached solar enclosures of unusual design.

Some aquiculture (or a combination of aquiculture and plant production systems) may be

possible in U.S. arid and semiarid zones, Preliminary tests suggest that aquiculture in the

West is feasible (27). For instance, recent

research in Nevada has shown that shrimp can

be grown in ponds heated by geothermal

springs or by warm wastewater from electric

Photo credit: USDA Soil Conservation Service

The potential for aquiculture in the Western United

States is high. In Texas, these channel catfish have been

seined from a pond and separated from other fish, From

here, they will be transported to a feeding pond

generating plants (30). Several Western States

have extensive hatchery and release programs

that could be further developed. Generally, the

potential for aquiculture is rated highly. There

is an extensive market for seafood in the United

States and more than 50 percent is imported

(7). Few aquiculture attempts have been undertaken commercially in the Western United

States, however, and the further development

of integrated plant/fish and fish systems faces

severe constraints. For example, water requirements for fish culture could be substantial and

require diversions from other uses. Other problems include:

inadequate funding for research and development;

poor marketing practices;

inexpensive imported products;

regulatory controls, especially standards

for waste discharges;
Ch. XI—Selected Technologies Affecting Water and Land Management ● 313

.

● uncertain availability of high-quality water;

lack of trained personnel; and

overcoming a bad image from past failures.

For these and other reasons, aquiculture is

not expanding rapidly in the United States.

Government, industry, and academic experts

have recommended that the United States develop a national aquiculture development plan

and improve coordination of present Federal

programs in order to increase aquiculture’s

contribution to fisheries production.

Land Use Management

Most farms and ranches produce one product and use highly energy-intensive practices

such as chemical fertilization and pesticides.

With uncertain economic and resource conditions, such as increasing energy costs and

unknown water availability, such specialization may involve greater risks. Therefore, technologies that integrate different types of land

use and different types of agricultural and nonagricultural products hold promise for stabilizing economic risk and are perceived by some

as the direction of the future.

The technologies discussed in this section are

diverse and reflect a spectrum of agricultural

philosophies. For example, multiple land use

on rangelands falls within accepted traditional

practice, but the various types of alternative

agriculture are, by definition, not traditional

technologies.

MuItiple Use of Rangeland

INTRODUCTION

Rangelands in arid and semiarid lands are

being used increasingly by different kinds of

people for very different purposes. This is an

important feature of publicly owned rangelands and is required by law for Federal lands.

This concept is also being developed for some

privately owned lands. Under these conditions,

the highest animal, plant, or water production

per unit area is not necessarily maximized. For

example, plants that are “unproductive” in

—

agricultural terms may be allowed to remain

along streambanks for the other important

amenities that they provide. When the efficiency of water use is measured in terms of all

products per unit of water used, such multiple uses may be more water-use efficient than

would traditional single uses such as grazing.

Major present multiple uses of rangeland include livestock and wildlife grazing, recreation,

and mining. Uses that are less important include harvesting nonforage plant products,

such as seeds and nuts, providing military

reservations and waste disposal sites, producing nonmeat animal products, and producing

water for offsite use.

Al1 of these activities have hydrologic effects,

some greater than others. However, the relative

importance of each potential use and its impacts on water resources shift from area to area

and continue to change. In some States, public

rangelands provide a great deal of water-based

recreation; in others, mining activity is concentrated on these sites.

ASSESSMENT

Range managers often operate without an

adequate data base, making multiple-use management especially difficult. Because Western

grasslands were altered by human settlement

before data were collected, major gaps in the

understanding of the structure and function of

these areas exist. Early managers did not place

high emphasis on data collection. Even now,

the long-term effects of specific management

practices are unknown. For example, the results of stocking rates recommended by the

Bureau of Land Management for individual

users are not systematically monitored.

Intensive management of any resource is

made especially difficult under such circumstances. The tendenc y is to “maximize” all

uses, leading to the nonsustainable use of the

resource. Considerable debate has ensued recently over the results of applying the multipleuse concept to public range lands, Some contend that it wiII diminish the value of public

rangelands for grazing livestock. Others contend that multiple use discourages ranchers

25-160 0 - 21 , Q~ 3
314 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— . ——.—. — — —

Photo credit” U.S Department of the Inferior, National Park Service

Federal lands provide a great deal of water-based

recreation, including fishing, swimming, and boating

from overgrazing and will, in the long term,

improve range conditions.

Many factors outside of the agricultural sector determine the future importance of multiple uses of all land types. The growing Western

urban population has led to the increase in

recreational use of rangelands. The search for

new energy sources has stimulated mining activities. Some of these activities are discussed

below.

Factors Determining Future

Multiple Use of Rangelands

Wildlife.—Arid and semiarid rangelands

provide habitats for a significant number of

wildlife species, including mammals, birds,

and fish. These animals attract large numbers

of visitors to the region and are of great interest

to residents as well. Wildlife considerations

strongly influence water management on many

rangelands, and intensive water management

has important effects on wildlife. Technologies

for wildlife management usually do not require

additional supplies of impounded water but

may result in increased rangeland productivity per amount of water used (21,27).

Wildlife species normally require freshwater

of reasonably good quality. Water consumption

rates are virtually unknown for most wildlife

species, but they are not thought to be great.

For example, total water consumption by big

game animals may range from 100,000 to

130,000 acre-ft/year for the entire Western

range (27). Water distribution and quality are

more critical factors. Bighorn sheep are

adapted for high water conservation, but their

distribution depends on available drinkingwater supplies. Mule deer populations show

major changes if the nearest water supply is

farther than 3 miles (38).

Inland rangeland fisheries depend on the

maintenance of lakes, perennial streams, ranch

ponds, and reservoirs. These features also provide habitat for waterfowl, an especially important rangeland resource in the northern Great

Plains. Water levels must be consistently maintained for fish and waterfowl to survive. Sometimes this is not economically feasible and usually it is not legally required.

Irrigation in the same watershed may lower

water tables and reduce both streamflow and

riparian and upland wildlife habitat. Other

agricultural practices, such as the use of

chemical or mechanical methods to eliminate

unwanted plants, alter the cover and food

supply on which wildlife depend. After considering the major effects that agricultural

practices can have on wildlife, the National Research Council (21) recommended that there

be three requirements for optimizing all resources, including water and agricultural production. These are:

● promotion of attitudes encouraging

stewardship of wildlife;

● additional critical research on conservation tillage, irrigation patterns, pesticide
Ch. X/—Selected Technologies Affecting Water and Land Management ● 315

— —

effects, and nutrients in aquatic systems;

and

c consistent public policies that use incentives to enhance fish and wildlife habitats.

Recreation.—Recreational use of rangelands

has increased dramatically in recent years.

Much of this activity is water-based, either directly—e.g., fishing—or indirectly —e.g., hunting. Some recreational activities make extensive use of shorelines of existing water bodies.

Range managers sometimes develop new

sources of water from natural seeps, low-yield

springs, and wells for these uses. These developments supplement and expand water supplies on rangelands. However, goals for livestock production and recreational opportunities sometimes are incompatible and management is difficult. In Texas, for example, where

deer and other wildlife are hunted through

leases, ranch managers often give more attention to providing accommodations to hunters

than to actual management of the deer herds

(8),

The income from hunting leases to a rancher

with private lands can be substantial. In Texas,

where there are few public lands available for

hunting and most private lands are protected

from trespassing, hundreds of thousands of

acres are leased for hunting each year at prices

of up to $10 per acre (8). Income from leasing

in many cases exceeds that from the sale of

livestock, the primary use of the land. Hunters

paid landowners $108 million for leases in 1971

(2], and the average cost of each lease has increased two to three times since then (21).

Applegate (1) asserts that Texas is representative of other States and that there are examples of ranchers in every State who lease

hunting land. In Oregon, where public land is

available for hunting, leasing arrangements on

private ranches are increasing. In many areas

of the West, though, the lands used for recreation are public lands. Income from hunting permits and tourism accrue to the States and local

businesses, not to ranchers.

Nonforage Plant Products.—Uses and income derived from nonforage plant products

are not well documented, but they are significant for certain users in certain areas. For example, seeds are harvested in some areas for

range reseeding, mineland reclamation, and urban horticultural use (fig. 73). Some seeds may

bring prices as high as $8/lb (12).

Pinyon pine nuts have been a staple food

source for American Indians throughout the

intermountain States. The few nuts reaching

urban markets are prized, Potential exists for

maximizing production of native stands and

also harvesting nuts from areas unsuitable for

any other crop. Some range plants have potential as biomass fuel sources (see ch. IX for a

detailed discussion). Other potential plant

products include wooden jewelry and fibers for

basketry and paper. These activities will probably continue and may increase in the face of

declining water supplies for other uses,

Nonmeat Animal Products.—The production of many nonmeat animal products, such

as fur, wool, and hides, can increase substantially without seriously affecting water resources, Since most produced now are not

sold, their sale would represent an increase in

agronomic water-use efficiency. See the discussion on animal mixtures, below,

MULTIPLE-USE TECHNOLOGIES

The multiple-use concept has been instrumental in shaping technology development and

adoption for rangelands, Two examples follow,

one in which technology developed for the

mining industry is moving into agriculture and

one in which agricultural technology was refined by multiple-use demands,

Surface-Mined Land Reclamation

Introduction.— Mining activity is widespread on Western rangelands and on some

crop and pasturelands. Coalfields in Montana,

Wyoming, North Dakota, South Dakota, Utah,

Colorado, New Mexico, and Arizona underlie

more than 100 million acres. Approximatel y 9 0

additional minerals are found in sufficiently

large deposits to be mined,

Mining activities influence water in many

ways. Water that flows through a mining area

may be degraded in water quality, a conse-
316 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands— —

Figure 73.—Summary Information for Using Big

Sagebrush in Rangeland Reclamation

Big Sagebrush (Artemisia tridentata)

Characteristics

Height:

Spread:

Growth form:

Root-system type:

Habitat

Distribution:

Elevation:

Topography:

Salt tolerance:

Drought tolerance:

Soil:

Use

Forage value:

Erosion control:

Landscaping:

Propagation

Seed:

Vegetative:

1.5 to 9 ft (0.5 to 3 m)

1 to 5 ft (0.3 to 1.5 m)

Round, generally erect, multibranched, evergreen shrub

Deep, spreading

Nebraska to eastern California,

south to New Mexico, Arizona

1,500 to 10,600 ft (495-3,500 m)

Wide spread, low-elevation

rangeland to mountain slopes

Fair

Good

Fine- to coarse-textured, acidic and

basic, moderate to deep, well

drained

Important for wildlife on winter

rangeland

Control mass-soil slippage

Gray-green foliage

Good germination at room

temperature but is speeded at cooler

temperatures: seeds ripen late

September

Collect stem cuttings Feb. to April —

treat with 2.0°/0 IBA powder

SOURCE Institute for Land Rehabilitation, Select Ion, Propagation, and Field

Establishment of Native Plant Species on Disturbed Arid Lands,

Utah Agricultural Experiment Station Bulletin 500, 1979

quence of the mining process (ch. IV). Substantial water supplies may be required during mining operations and stream widening. Lake

drainage, surface-flow diversions, streambank

disruption, and ground water interference may

all occur. Collectively, mining activities affect

water supplies and the use of the land for agriculture.

Mining also has indirect effects on water use.

Surface mining destroys existing natural communities completely and dramatically. Because

water is the major factor in revegetating these

areas, many reclamation efforts focus on water

use and management.

Assessment.—Most arid and semiarid

rangelands have not and will not face such

drastic disturbances. Probably only a small

percentage of all rangelands will be surface

mined for coal. Yet water remains the key to

maintaining or restoring rangeland productivity. As a result of these similarities, many reclamation technologies can be used directly on

other rangelands. This is important because

Congress has mandated improving the condition of the 160 million acres of public rangelands in the 17 Western States and recent legislation* established a national commitment to

maintain and improve public and private

rangelands, making them as productive as feasible for all rangeland values. Until now, such

improvements were slow and few technologies

existed.

Reclamation technologies are not expected

to increase agronomic water-use efficiency of

plants or animals greatly, but preliminary

research suggests that some gains can be made

(27). A variety of technologies are possible:

c water-retention methods to speed plant

establishment and minimize runoff,

● plant breeding for hardy and palatable

grasses,

● planting and seeding technology,

● soil building techniques, and

— —.

* Forest and Rangeland Renewable Resources ~lanning Act,

(public Law 93-378]; Public Rangelands Improvement Act,

(Public Law 95-514).
—

Ch. Xl—Selected Technologies Affecting Water and Land Management ● 317 — —. . —

● management of vegetation composition

and ecosystem analysis.

Dryland sodding is an example of a technology to prevent erosion and to establish plant

cover rapidly. With this technique, thickly cut

native sods containing grasses, forbs, and

shrubs are placed on steep, erosive slopes and

special machines have been developed to handle native sod efficiently and effectively.

In the past, rangeland managers avoided the

use of many potentially useful plant species on

undisturbed lands owing to problems with seed

size and shape, low germination, or seedling

vigor. Because regulations require large proportions of native plants in reclaimed areas,

new planting and seeding technology was stimulated. Special techniques and equipment now

exist for harvesting, treating, and planting fuzzy, awned, sticky, minute, or otherwise troublesome seeds. In some cases, the vulnerable seed

and seedling stages are protected by specially

designed containers or underground stem and

root transplants are used in revegetation efforts

on marginal or “impossible” sites.

The productivity of some undisturbed range

sites is limited by soil conditions—e. g., high

sodium or clay content—that affect nutrient

and water availability as well as toxicity to

plants. Surface mining requires the complete

reconstruction of soils. Therefore, reclamation

research has stimulated the development of soil

building technologies that have the potential

for transfer to other lands. These include the

use of biological, chemical (organic and inorganic), and physical amendments to the soil.

Most surface mining regulations have rigid

requirements for determining the success of

reclamation. In some cases, the composition

of vegetation is specified. As a result, interest

has increased in vegetation management methods as well as in long-term ecosystem analysis.

Some management methods, such as rangeland

fertilization, burning, irrigation, interseeding,

and grazing, were developed for undisturbed

rangelands but are being refined by reclamation efforts. Others, such as long-term analyses

of plant/environment interactions, are seldom

—

matched in duration or intensity by traditional

rangeland research (25).

Legal, social, political, economic, and cultural factors may be barriers to implementation

of reclamation technologies on undisturbed

rangelands. For example, Federal law on the

use of native plants and land with agricultural

potential has affected State regulation and research. Schechter (24) maintains that R&D are

inadequate and that capital does not exist to

meet this need, A single discipline focus

hinders application of the research that has

been done. For example, undisturbed rangelands may contain more than 40 plant species,

but revegetation efforts often focus on a single

species. Moreover, there is a general lack of

understanding of soil biota. More information

about complex multiple species interactions is

needed, a task requiring an interdisciplinar y

effort.

Economic return varies widely among Western agricultural land uses, making certain

technologies suitable for some lands but not for

others. For example, private companies may

spend $2,500 to $6,000/acre to reclaim land that

has been surface mined for coal (14). A nearby acre of undisturbed land may sell for $200.

Clearly, reclamation is costly, even when

disturbance is less drastic than that from surface mining. Improvement of unmined but degraded public rangelands using a variety of

technologies would represent a major economic investment. The Bureau of Land Management has a backlog of $34.7 million in needed

range improvements, and the cost of additional

projects is estimated to be over $148 million (37).

Management of Undesirable Plants and Animals

Introduction. —Range managers identify a

number of plants that decrease livestock forage

or have other undesirable features. Some of

these plants are not natives of the West but

have spread after introduction from other parts

of the world. Undesirable plants maybe highly

adapted to arid and semiarid conditions and

therefore difficult to remove once established.
318 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Photo credit: USDA-Agricultural Research Service

The Range Improvement Machine is being developed by USDA/ARS in cooperation with Montana State University for use

on semiarid rangelands and marginal pasturelands to increase grass and forage yields. It uses a packing wheel system.

For purposes of water conservation, the gap in each wheel leaves a check dam at 7-ft intervals (inset)
Ch. Xl—Selected Technologies Affecting Water and Land Management ● 319 —.

The definition of plant pests depends on the

intended land use and the specific site, but

plants such as mesquite, oaks, and sagebrush

are often considered to be undesirable by

ranchers.

Human use of rangelands has exacerbated

the increase of plants considered undesirable.

Intensive grazing, the exclusion of fire, and

temporary cultivation have changed the composition of plant communities. Invasion of

woody species also decreases the availability

of forage for livestock and is the primary cause

of rangeland degradation. Therefore, technologies to control “brush” are one way to increase rangeland productivity. Usually, large

amounts of water are not directly involved in

these technologies. Instead, increases in productivity lead to higher water-use efficiencies.

Other applications of these technologies may

be made to increase water runoff specifically

(ch. VI),

In some parts of the West, principally in public rangelands in Utah and Nevada, wild horse

and burro populations also degrade lands. Ex-

—. —

perts estimate that 60,000 to 70,000 wild horses

compact soils, overgraze plants, and generally interfere with careful rangeland management and optimal use of forage. Programs to

control these and other animals are used to

achieve three management objectives: 1) protect livestock, 2) reduce the number of herbivores that compete with livestock for available forage, and 3) protect the range from overgrazing and subsequent damage to productivity. Most control programs seek to optimize

population size, not to eliminate all wil d

animals.

Assessment.—Studies of several plant

species indicate that control or removal significantly increases soil water, resulting sometimes in a concomitant increase in available

forage for livestock. However, not all stands

of undesirable plants use large amounts of water that would be available to other users, and

the amount of water affected depends on the

original type of vegetation, its density, local

precipitation, and the control method used. In

some cases, vegetation considered by ranchers

Box Z.—Integrated Brush Management: A New Approach for Degraded Rangelands

In the last few years, emphasis in range management has shifted from eradication of noxious

plants to their careful control by combinations of methods, known as integrated brush management, The basic principles include:

reducing dependence on any single control method,

using the synergistic effects from treatment combinations,

increasing both livestock and wildlife habitat,

developing flexible treatments for different conditions,

integrating treatments with other management techniques, and

enhancing economic returns from brush management.

These techniques are applicable to most sites, but to be successful they require long planning

horizons: brush-management systems are designed to span 15 or 20 years. These program are expected to be adopted first in areas that have major brush problems. For the next decade, Texas,

Oklahoma, and New Mexico will probably be most involved. Adoption could increase rapidly if

costs of other range-management technologies or Federal constraints on herbicide use increase.

The costs of these techniques vary widely, and there are additional indirect costs and benefits.

primar y constraints to implementation are economic, especially for the first costly step in a sequence. Technical constraints are significant since research still is in the formative stage and treatment testing requires long time periods.

SOURCE U.S. Congress, Office of Technology Assessment. Impacts of Technology on U.S. Cropland Rangeland Productivity (Washington, DC: US Government

Printing Office, OTA-F-166, August 1982)
. — —.

320 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

to be undesirable provides important benefits.

For example, most stands of trees and shrubs

furnish wildlife habitat. They may also provide

shade for livestock, protect soil from wind or

water erosion, increase water runoff for offsite

uses, or contribute to the attractiveness and diversity of arid and semiarid lands.

Each of the common brush-control technologies has advantages and disadvantages. Mechanical control is labor- and energy-intensive

and thus expensive. After chopping and clearing plants, some residue usually remains,

which is advantageous, but considerable soil

disturbance also occurs. Chemical control is

specific, effective, and often less expensive, but

some chemicals, improperly applied, may

cause crop damage or health hazards. Regulations largely prohibit chemical use on Western

——.——

Federal rangelands. In contrast, fire, always a

feature of Western rangelands, is gaining acceptance as a major control technology. It is

inexpensive, but all areas cannot support fires

and the resultant denuded ground is subject to

soil erosion.

These conventional control technologies

have been criticized for being used without

regard to their effects on values other than

livestock production. Integrated brush management is a newer technology that has the potential for enhancing multiple-use values of rangelands. Some experts contend that this technology can make a large contribution to increased

water availability for agriculture on rangelands,

With an integrated approach, it is possible

to manage noxious plants for their potential

Photo credit: USDA-Soil Conservation Service

Fire is gaining acceptance as an effective brush-control technique. Here, junipers are ignited

to increase forage production on rangeland in Arizona
Ch. XI—Selected Technologies Affecting Water and Land Management . 321

benefits. For example, because mesquite may

form very dense stands, and cattle sometimes

have difficulty digesting mesquite pods, mesquite is often considered to be noxious. But

these trees have traditionally been used for

food, forage, and firewood production by

Southwestern Indians who considered mesquite’s importance greater than that of corn

and wheat. Unripened and ripened pods and

seeds were eaten by humans and animals, and

the wood continues to be prized. There is evidence that selected varieties of mesquite could

become nitrogen-fixing, low water-using crops

which require little or no tillage (11), Big

sagebrush is also commonly regarded as a noxious plant because it is aggressive and unpalatable to domestic livestock. For these reasons

it has been the target of widespread eradication programs. An alternative approach would

be to use the richly variable germplasm base

to improve the species’ forage qualities.

An integrated management approach can

also be used for noxious animals, but wild

horse and burro control represents a particularly difficult problem. These animals are without

effective predators and are capable of rapid

population increases. They can inflict heavy

damage on rangelands. Both offsite and onsite

effects on water resources have been noted but

never quantified (20). Transplanting animals

is only a temporary solution, fertility-control

with drugs is expensive, and selective killing

is sometimes strongly opposed by the public.

Animal Mixtures on Rangelands

INTRODUCTION

Different animals have different food preferences, i.e, they consume different plant

species, different parts of the same species, and

the same plant parts growing at different

heights. Therefore, mixtures of animals use

resources more fully than any one species.

When species more adapted to dry conditions

are included, they may also use resources more

sustainably.

. —

ASSESSMENT

Some experts feel that animal productivity

can be increased by stocking rangelands with

more than one kind of animal (10). For example, new combinations of livestock and wildlife

species could double range productivity in

some areas, and an optimal grazing management scheme for shortgrass range sites might

allocate forage to cattle (67 percent), bison (20

percent), sheep (12 percent), and antelope (1

percent) (17). Sheep and goats graze over wider

areas and rougher terrain than do cattle, Used

in combination, they could control brush and

weed invasion resulting from overgrazing by

cattle.

Few range managers have attempted operations of this complexity. Ranchers with private

lands—e.g., in Texas—have the most ex perience with large mixtures of animal species.

These mixtures usually include unusual exotic

animals that are stocked for recreational hunting or photo safaris, not for large-scale meat

production. This concept awaits full-scale testing with North American game and domestic

animals.

Optimal combinations of herbivores can only

be determined if the diet-selection process is

understood. Currently, no models exist that can

define this process and it is not possible to

predict dietary or spatial use of any given site,

The limited numbers of experiments with

mixed-species grazing systems do not provide

information on their long-term effects. For example, little is known about the effects of such

systems on overall efficiency of energy use or

of nutrient cycling. Furthermore, little is

known about the effects of larger numbers of

sheep on populations of big game animals.

When more than one species of animal

grazes an area, it is critical to match demand

to available vegetation. Overlapping plant preferences could destroy a plant species before

the process is apparent in declining animal

health or numbers. Innovative approaches are

needed to study the responses of mixed animal
322 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— —.-——

Box AA.-Alternative Agriculture in Arid/Semiarid Lands: The Innovators

It maybe decades before alternative agriculture is practiced widely in arid and semiarid lands.

Pioneers are at work now, and it may be their work that shapes the future of American agriculture.

Workers at the Land Institute in Salina, Kans., are developing a grain-producing system that

mimics the diverse and productive grasslands which once flourished on the Great Plains. They

use perennial plants to decrease tillage and erosion; legumes and quickly decomposing composites

to cut fertilizer needs; and unusual germplasm to increase nutrition and seed yield.

Cooperative studies between botanists at the Arizona-Sonora Desert Museum (Tucson, Ariz.)

and the University of Arizona explore the potential for crop mixtures of short-lived desert plants

and perennials. Native plants such as mesquite, tepary beans, gourds, devil’s claw, and cacti are

blended with biological technologies for fertilization, pollination, and soil-water absorption.

The Agroecology Program at the University of California, Santa Cruz, focuses on research and

small-scale field trials of new systems. Experiments include ones on integrated pest management,

pollination, multiple cropping, the use of fire in agriculture, trees as crops, farm pond aquaculture,

and comporting. Part of this program is tailored to students, but it also includes cooperative projects with local farmers and extension agents.

Rodale Press has been a leader in the alternative agriculture movement and, with the establishment of the Rodale Research Center, it produces careful and credible agronomic research. This

center, especially through its work with grain amaranth, is now working more with crops for dry

lands. A new consulting role in foreign arid lands can be expected to strengthen these aspects

of its program.

species on different types of range sites, especially where sustained productivity of wild and

domestic species is the goal.

The combination of domestic livestock—e,g.,

sheep and goats with cattle—has not been practiced extensively, The sheep and goat industries are both relatively small, providing a

limited market for new technologies and constraining innovation, The sheep industry, after

a sharp decline due to low returns, high labor

requirements, and losses to predators, seems

to be at the beginning of a modest recovery owing to increasing competitiveness of natural

fibers. Both sheep and goat producers face

strict regulations that favor cattle producers,

Alternative Agriculture

INTRODUCTION

The predominant agricultural systems used

in the arid and semiarid parts of the United

States represent a fraction of the kinds of systems available worldwide. Present systems are

largely based on frequent tillage; the use of a

few, very specialized, annual crops; and additions of large amounts of added synthetic fertilizers and pesticides. While these systems

predominate, some Western farmers do not use

them.

Some farmers and ranchers are experimenting with types of agriculture that are quite different. These new systems are diverse and may

include complex mixtures of crops in one field

(polyculture or intercropping); they may include perennial grains or tree crops instead of

annuals such as corn, sorghum, and wheat

(perennial polyculture or permaculture); or

they may eliminate synthetic pesticides and

commercial fertilizers (organic farming), Generally, they rely heavily on natural biological

processes, such as nitrogen fixation by legumes, instead of artificial replacements, like

fertilizers (table 81),

ASSESSMENT

Such alternative agricultural systems have

demonstrated their usefulness under certain

conditions. Some scientists observe their in-
Ch. Xl—Selected Technologies Affecting Water and Land Management ● 323

— — —

Table 81 .—Examples of Human Substitutions for Biological Processes

Biological process displaced Non biological process substituted

Natural fertilization in plants/seed dispersal Plant breeding/harvesting of seeds

Fixation of atmospheric N by bacteria Application of artificial nitrogenous fertilizers

Exploration of soil by roots for potash and phosphorus Application of artificial fertilizers; irrigation

and water

Natural control of pests and weeds Use of pesticides and herbicides

Collection of feed by animals Harvesting, processing and automated provision of

compounded feed; forage conservation

Grazing Zero-grazing (the cutting and carting of herbage)

Natural deposition of excreta on the land Collection of excreta from housed animals and its

disposal, treatment or distribution on land

Incubation of eggs by hen birds Artificial incubator

Natural service by male animal Artificial insemination

Natural hormonal processes Control of light, day-length and temperature; use of

synthetic hormones

Natural suckling (of calves and lambs) Artificial rearing on milk substitutes

Natural immunity to disease in animals Use of vaccines

Use of animal power Use of machines and fossil fuel

SOURCE C R W Spedding J M Walsingham and A M Hoxey. Biological Efficiencyin Agriculture (London, U K Academic Press, 1981)

creasing credibility and expect that they will

assume greater importance in the future (23).

The advantages claimed for these systems are

many and include lower use of expensive, fossil fuel-based chemicals that may be hazardous

to human health and the environment, improved soil structure and better growing conditions for plants, less soil erosion, a more

diversified and therefore more stable agricultural base, more nutritious agricultural products, and more efficient use of natural resources.

Some of these claims have been substantiate]. For example, farms producing a variety

of products generally reduce their risks and increase the effective use of total resources. Polycultures of plants grown together, in contrast

to monoculture of one plant, may use soil nutrients more efficiently, increase economic

returns, improve the nitrogen status of crops

when legumes are part of the mixture, and provide stability of yields over time (16). Systems

that eliminate synthetic chemicals also eliminate the possibility of pesticide contamination

and minimize contamination of ground water

and runoff from commercial fertilizers (21).

Organic farming has been shown to increase

wildlife populations and in at least one Western

State, the U.S. Fish and Wildlife Service recommends it for producing crops for wildlife (29).

Other claims, such as the effects of organic

farming on crop nutrition, are less well understood and many need further research.

The earliest advocates of these technologies

based their arguments on ideological grounds

or on the perception of severe environmental

problems resulting from traditional agricultural

practices, More recent practitioners are adopting alternative systems on economic grounds,

For example, most of the cornbelt/Great Plains

organic farmers surveyed by Strange (29) cited

the importance of lower production costs and

insulation from rising variable input costs,

One-fourth of these farmers borrow no operating capital. Many of these people also share

a belief that farmers and ranchers should not

exhaust the natural resources on which the

future of agriculture depends. For this reason,

they feel that alternative agricultural systems

are among the most forward-looking and resource-conserving of technologies under development.

Both basic and applied research on alternative systems have been limited. This research

is not simple: controlled experimentation is difficult, no one type of alternative agriculture is

representative, and the benefits claimed to accrue may take decades to manifest themselves.

Public and private investment in research is

small. For example, USDA formally decided

to terminate research in this area contrary to
324 “ Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

. ——..—-—.-—— —

the results of its own study (35), Interested

farmers have had few places to get information. One survey of organic farmers showed

that only 5 percent sought or received help

from land grant universities and only 3 percent

could find assistance from extension agents

(29). A more extensive foreign data base exists

for some technologies, such as the polycultures

of India, France, and Africa, but this information generally has not been adapted for use in

the United States.

Research is lacking also on alternative systems for arid and semiarid lands, For example, most research on organic farming has been

done in humid regions of the United States.

Polyculture systems, such as those extensively used in India, are more common in arid regions and they generally perform better in dry

seasons. But claims that polycultures use water

more efficiently or are able to tap water unavailable to monoculture have not been substantiated. For these reasons, it is impossible

to predict under what site-specific circumstances polyculture will prove to be advantageous.

This lack of information has contributed to

an absence of organizations to assist producers

with questions and problems related to alternative agriculture. The people who are interested in many of these systems generally are

not part of the traditional agricultural community and are not well organized among themselves. Therefore, knowledge of alternative

agricultural systems has had limited acceptability and visibility. There is evidence that the

tendency to dismiss new systems as impractical or bizarre may be declining. For example,

under a congressional mandate*, USDA completed its first study of organic farming in 1980,

and the University of Nebraska holds an annual organic farming field day. Large numbers

of farmers continue to express their interest in

alternative methods despite the lack of official

encouragement.

It is not clear yet to what extent these technologies will be applicable to farms or ranches

‘Section 1461 of Title XIV of the Food and Agriculture Act

of 1977 (J’ub]ic Law 95-1 13).

of varying sizes and in different geographic

locations. Most of these systems are highly integrated and require good management skills,

substantial knowledge about plants and animals, and marketing expertise. The need for

these skills may place low limits on the size and

scale of a particular enterprise. While the productivity of some farming systems maybe high

per unit of land, the labor intensiveness may

make productivity per farmer or rancher relatively low.

There is no consensus whether these systems

would produce, in the near term, yields as large

as those currently achieved. For example, some

experts feel that the widescale adoption of

organic farming would result in lower, but acceptable, total productivity (4). Other results indicate that adoption of organic farming practices might actually increase farm unit production by decreasing operating costs. The greatest

benefit of these systems is in sustaining or improving inherent land productivity, This benefit could compensate for short-term yield

reductions if they materialized (33).

Multiple Use of Croplands

INTRODUCTION

Rangeland uses for recreation and wildlife

are important adjuncts to meat production in

many areas. Similar multiple uses of cropland

are possible, and some farmers are actively pursuing this option. In fruit, nut, and vegetable

growing areas, some farmers invite customers

to pick their own produce. Farmers may provide other services, such as hayrides to fields

or samples of processed produce. Management

of some areas emphasizes, for the visitor, the

recreational aspect of the visit,

Grain-growing areas provide important wildlife habitats and some States allow leasing them

for hunting. In Texas and California especially, irrigation and cultivation practices can

sometimes be managed to increase wildlife

habitat. The large pheasant and waterfowl

populations that often result provide an opportunity for farmers to lease land at attractive

prices.
Ch. XI—Selected Technologies Affecting Water and Land Management ● 325 — - — .-. . . —— — —

ASSESSMENT

It is difficult to assess either the present or

potential role of multiple uses of cropland. No

central source of information exists on these

land uses. For some areas, though, it is clear

that wildlife and hunting uses of cropland are

having a large economic impact.

Wildlife in many areas have suffered from

recent agricultural practices. Fencerow-tofencerow cultivation, removal of grain stubble,

intense grazing of pastures, and extensive

weed and pest control have adversely affected

wildlife. These practices partly reflect the drive

for higher agricultural production and partly

the feeling that wildlife is a farm liability. Thus

in some areas, recreational use of cropland is

unlikely in the face of negative attitudes. Hunting on croplands is also limited by farm schedules. Hunting season may occur during harvest

or other busy times when it is not practical to

have visitors in the fields.

In other areas, agricultural practices have

enhanced wildlife, and farmers have welcomed

and used this increase (table 82). In South

Dakota, small-game hunters purchase a $5

wildlife stamp in addition to their hunting

licenses. The revenues generated are then paid

to landowners for the maintenance of pheasant

nesting cover. More than $500,000 was paid

in 1979 to farmers at an average rate of $22/

acre. After 5 years in operation, 535 landowners are involved and about 15,000 acres of

cropland have been diverted for wildlife purTable 82 .—Gross Revenue to Western Statesa From

Hunting and Fishing Licenses in 1981

State Hunting licenses ($) Fishing licenses ($)

Arizona ., . , — 3,585,167

Californi a 7,005,827 24,156,555

Colorado. . . . 18,370,746 5,436,643

Idaho ., ., . . 5,322,771 3,100,745

Montana ., ., ., 4,688,759 3,797,090

Oklahoma ., . . . . 4,564,625 4,144,402

Oregon . . . . 7,543,558 6,408,517

Texas . . . 6,314,663 7,406,271

Utah . . . ., 5,598,120 5,129,323

Washington . . 5,867,014 6,704,656

Wyoming . . . 10,919,365 —

aStates included rank among the top 25 in the United States in terms of State

revenue from these activities

SOURCE U S Department of Agriculture, Soil Conservation Service Texas Conservation TIPS, December 1982

poses (l). Some wildlife species do not benefit

from such programs: in areas in which land

conversion among rangeland, cropland, and

pastures occurs, only those animals adapted to

changeable conditions are favored,

Set-aside programs for wildlife are expensive

to the organizers and may not encourage wide

participation. The multiple use of farmland,

therefore, depends on strong economic incentives for individual farmers. This is the case

when croplands are leased for hunting. In Texas, for example, farmers are being encouraged

to consider pheasants as a cash crop and to

plan management decisions to accommodate

gamebirds. By planting wheat, sorghum, and

corn to provide cover and food in proximity

to water, farmers can enhance pheasant production. Ponds that capture irrigation water

runoff also have become prime pheasant habitat where farmers can encourage the growth

of important gamebird vegetation. During

hunting season, these practices translate into

leases to individual hunters or sports clubs at

a minimal cost of $25/person/day or $125/person for the season’s opening weekend (28).

In Texas and other States where irrigation

has changed the face of agriculture, the availability of water supplies may determine the future of both agriculture and wildlife. Changing water use in the Central Valley of California has had major effects on wildlife and has

made hunting an important use of irrigated

land. In many cases, the changes in in wildlife

habitat or populations inadvertently accompanied changes in agricultural technology.

Table 83 shows some of the more general interactions between technological changes and

resources in the Sacramento Basin of California. Specific changes may also be traced. In

fewer than 100 years, about 5 million acres in

the Central Valley were converted from grasslands, marshlands, and waterways to high-value farmland and urban areas. As a result, a

number of species of waterfowl have become

dependent on cultivated cereal crops, whereas

other species dependent on the natural vegetation have declined. Pastures and fields of corn,

rice, mile, wheat, and barley provide habitat

for large numbers of migratory and resident
I

Table 83.— Relationships Between Agriculture Practices and Fish and Wildlife, Sacramento Basin and Delta-Central

Sierra Hydrologic Study Areas

Opportunity Agricultural viewpoint Fish-wildlife-recreation viewpoin t

Practic e for water savin g Positiv e Negativ e Positiv e Negativ e Comments

One of two true

means of saving

water in basins

Increase ground

water pumpage

Possibly very large

Moderately large

Farmers gain

operating independence and dryyear flexibility

Increased dry-year

supply

High initial cost;

big energy user

Reduces diversions

from river

May increase percolation

Increase reservoir

storage

None Decreases peak

flows; increases

dry-year summer

flows; enhances

reservoir-type

fisheries

Would tend to

reduce diversions

from the Sacramento River, leaving more water for

in-channel use

Would flood out

native lands

Opportunity for

true in-basin

water savings

Reduce water applied to rice

Large, possibly

several hundred

thousand

acre-feet

Should produce a

large net saving in

applied water use;

save energy and

fertility

Would increase irrigation management costs; increase TDS of

drainage water

Would decrease

drain flows,

hence diminish

riparian vegetation and fish

flows, increase

TDS and water

temperatures

Elimination of

berms would reduce wildlife

habitat

No savings would

result unless

storage provided

Level all rice paddies, form rectangles

Included above Would decrease applied water use by

an estimated 5%;

increase yield,

reduce water man -

agement and har -

vest costs, increase net profit

Would reduce wate r

use; increase forage productio n

Would take land

out of production for one crop

year; require

capital outlay

Included above Now catching on

rapidly in ricegrowing areas

I

Drain wet mountain meadows;

improve water

management

Small Would require annual maintenance cost; high

original investment

None Would reduce

wetland habitat

reduce late summer downstream

flows

As time goes on,

practice will be

employed

through the incentive to increase forage

production

Must develop

incentives for

districts to take

action; must persuade people

that water-saving

practices are

necessary

I

District practices;

canal lining (reduce seepage);

Large, could reduce district demands

These practices will

decrease water demands on a district basis; could

increase yields and

decrease fertilizer

needs

Would require None Would reduce

wetland habitat.

reduce fish

flows, raise water temperatures,

increase TDS,

concentrate

pesticides, and

increase channel

velocities in

some areas

more energy,

capital, and manpower, increase

the unit cost of

water, leave

drain water

users with no

available supply

increased use of

relift pumps,

control ditch

bank vegetation,

clear channels

SOURCE State of California, Department of Water Resources Bulletin No 198, May 1976

—
.— .— —. —

Ch. Xl—Selected Technologies Affecting Water and Land Management ● 327

. ..- .——— . .

waterfowl. In some parts of the valley, farmers

can realize significant economic returns from

leasing hunting rights. These farmers may

flood cornfields and create wetlands instead

of planting a second crop to increase waterfowl populations, In some cases, this practice

also removes salts that have built up in the soil

from previous irrigations. A large number of

duck clubs now makes use of these croplands.

For example, at least 84 private duck clubs exist

in San Joaquin County, Calif., and about onethird, or 12,000 acres, of the land leased for

hunting represents flooded fields.

In other areas, irrigation water is becoming

less available, and careful management is

undertaken. For example, where rice is grown,

land leveling—the use of fewer levees between

fields—and more productive rice varieties have

increased yields but decreased both cover and

food for wildlife. In these areas, wildlife

populations have declined. Some experts feel

that the situation is becoming critical. Greater

pressures for careful irrigation management

are driving farmers to use less water, and they

cannot be expected to continue to sustain large

water-dependent wildlife populations.

Computers and Information

Management

Inroduction

Ranchers and farmers manage information

daily, Decisions regarding which crop to plant

or when to sell livestock, for example, are based

on obtaining and evaluating information from

a variety of sources. The availability of electronic computers has changed the nature of information management, and computers are

rapidly becoming everyday tools in agriculture.

Agricultural scientists have used computers

for research analyses for some time. The direct

availability of computer-assisted analysis to

ranchers and farmers is more recent. Computers are having an impact in two different

ways:

1, university/State extension services are

providing access to large, shared computing facilities through networks of terminals; and

2. producers are purchasing microcomputers

for home use.

The large computer systems share central

data storage and processing facilities. The Agricultural Computer Network (AGNET) is a good

example. AGNET was developed by University

of Nebraska scientists in the 1970’s and expanded into five Western States on a pilot basis

in 1977. As of 1980, six States are full partners

in the operational system: Montana, Nebraska,

North Dakota, South Dakota, Washington, and

Wyoming. AGNET relies on a large central

computer in Nebraska and the backup skills of

nearly 20 computer specialists in the participating States. Extension Service offices and individual users gain access via local terminals

to program libraries. These terminals can be

as simple as touch-tone telephones or as elaborate as nonportable terminals with video

screens and printer attachments.

AGNET was designed to be a tool for making farm and ranch management decisions and

for providing up-to-the-minute market news

and extension information. Over 200 agricultural programs are available now to users and

it is considered to be the best system available

to farmers and ranchers today. Programs include ones for cattle production, tax planning,

machinery costs, home food preservation, irrigation scheduling, and soil loss. Farmers and

ranchers are often included in planning these

programs to ensure their usefulness.

Microcomputers (also called home or personal computers) can provide some of the same

facilities. These units often have a keyboard,

a video or television screen, magnetic data and

program disks and disk drives, and a printer.

They are self-contained and often users rely on

programs developed for their particular machine. Farmers and ranchers use these small

systems for business accounting as well as for

storing and analyzing records of herd performance. Some microcomputers have graphics

programs for displaying the results of analyses,

Telephone couplers allow microcomputers to

be used as terminals and provide access to the

large computer systems.
328 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Assessment

Some experts predict that computers will become commonplace during the 1980’s and that

the farmers and ranchers who do not use these

management tools will be out of business by

1990. Computers make recordkeeping more

precise and can help prevent management errors. Both of these elements are crucial when

profit margins are low and prices fluctuate

widely.

Farmers and ranchers with timely access to

large systems such as AGNET can use elaborate computer technology at minimum personal cost. They can use tools that were specifically designed for agriculture and many that were

tailored to conditions in the West.

Costs for direct terminals into large systems

such as AGNET vary from minimal monthly

telephone rental charges to $7,000 for the most

elaborate purchased ones, Several small portable terminals cost about $1,500. Also, users

pay long distance charges for the time during

which the computer link is actually made.

These charges may increase operating costs beyond the initial purchase price of the microcomputer. Purchase and operating costs are

usually borne by universities and cooperative

extension services in order to make terminals

available in county offices and for specialists

to use for local demonstrations, Some extension offices supplement large computer systems with microcomputers and are developing

special agricultural programs for them. For example, Utah State University is developing irrigation programs for their Apple microcomputers.

Agriculturists who rely on their own microcomputers will have fewer tools with agricultural applications immediately available. Telephone couplers into the larger systems are

probably necessary to have adequate agricultural programs. Such linkages provide the best

of the small and large systems, but they are far

from routine now. Microcomputers that are

sufficient for agricultural applications cost

$4,000 to $5,000 for the machinery, or hard-

.- —

Photo credit: USDA-Agricultural Research Service

Replacing the driver? Agricultural engineer Robert

Schafer presents tomorrow’s farmers with the circuit

board from a computerized guidance system for tractors

and other farm machinery, Research shows that

computer-controlled traffic across croplands

can reduce soil compaction considerably

ware, and an additional $2,000 to $3,000 for

programs, or software. The more elaborate and

expensive microcomputers also are more flexible, They are faster and easier to use, and their

standard features allow hardware and software

“extras” to be exchanged among different

brands,

The trend to greater reliance on computers

in agriculture has begun despite the substantial costs involved, A number of vital institutional issues remain to be resolved, including:

1) the role of the Federal Government in technology R&D, 2) the role of Federal and State

agencies in training, and 3) the need for improved cooperation among various agencies.

These issues may redefine the role of the

Cooperative Extension Service, alter the audience which it serves, and determine how widely Government-developed computer technology is distributed. For example, some experts

think that some extension services lag behind

vocational schools and even behind some high

schools in providing computer training.

Will Western agriculture participate fully in

the computer “revolution?” The technology is

available, but evidence suggests that Western
Ch. XI—Selected Technologies Affecting Water and Land Management ● 329

—

farmers and ranchers have trailed Midwestern- of water use, But computers can also be used

ers in its adoption, perhaps by as much as 10 as irrelevant and expensive toys; such uses will

years (15). It is clear that some computer ap- not necessarily help solve difficult water probplications can contribute to greater efficiency lems.

CONCLUSIONS

Agricultural management technologies that

affect water supplies in the arid and semiarid

region represent a wide combination of individual practices, including animal and plant

management, irrigation water management,

cultivation practices, and computer and information management. Each of these management technologies is used in recognition that

water is part of the natural system in which

it is impossible to affect any

fecting another.

part without afManagement technologies have high potential for maximizing production from available

water, plant, land, and animal resources in the

arid and semiarid region. Their application and

significance in the future will depend to a great

extent on research efforts by the scientific community, on economic costs and benefits of application, on managerial abilities of producers,

and on decisions by policy makers at the local,

State, and Federal levels.

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—

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330 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

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22. Parker, C. D., “Land Extensive Processes for

Wastewater Treatment and Disposal—A Perspective, ” Wat. Sci, Tech. 14:393-406, 1982.

23. Rushefsky, M. E., “Policy Implications of Alternative Agriculture, ” PolicuV Studies Journal

8(5):772-784, 1980.

24. Schecter, J., “Some New Directions in Arid

Zone Research, ” Arid Zone Research and Development, H. S. Mann (cd. ) (Jodhpur, India:

Scientific Publishers, 1980), pp. 483-489.

25. Sindelar, B., “The Relationship of Reclamation

Research to New Range Science Technologies,”

OTA background material, 1982.

26. Sopper, W, E., “Surface Application of Sewage

Effluent, ” Planning the Uses and Management

of Land, Marvin T. Beatty, et al. (eds. ) (Madison,

Wis.: American Society of Agronomy, 1979), pp.

633-663 (No. 21 in the series Agronomy).

27. Sosebee, R. E., Tueller, P. T., and Rittenhouse,

L. R., Technologies for Increasing Water Use

—

Efficiency On-Site, OT,4 commissioned paper,

1982,

28, Steiert, J., “Pheasant as a Cash Crop, ” Texas

Farmer-Stockman, p. 24, October 1982.

29. Strange, M., “Building a More Resourceful

Agriculture, ” Wildlife Management on Private

Lands, R, T, Dumke, G. V. Burger, and J. R.

March (eds.), Wisconsin Chapter of The Wildlife Society (Madison Wis.: La Crosse Printing

Co., Inc., 1981), pp. 357-370,

30. Taylor, R. E., “A Feasibility Study of the Pro31,

32.

33

34,

35.

36<

37.

38,

du&ion of Macrobrachium-Rosen& ergii (Giant

Malaysian Prawn) in Nevada, ” Final Report,

Cooperative Project University of Nevada, Reno

College of Agriculture, and Sierra Pacific Power

Company, 1980,

Thomas, R., Land Treatment Specialist with

U.S. Environmental Protection Agency, personal communication, 1982.

U.S. Congress, Office of Technology Assessment, Use of Models for Water Resources Management, Planning, and Policy (Washington,

D. C.: U.S. Government Printing Office, OTA0-159, August 1982),

U.S. Congress, Office of Technology Assessment, Impacts of Technology on U.S. Cropland

and RangeZand Productivity (Washington, D. C.:

U.S. Government Printing Office, OTA-F-166,

August 1982).

U.S. Congress, Office of Technology Assessment, Water-Related Technologies for Sustainable Agriculture in Arid and Semiarid Lands:

Selected Foreign Experience, Background

Paper (Washington, D. C.: U.S. Government

Printing Office, OTA-13P-F-20, May 1983).

U.S. Department of Agriculture, Report and

Recommendations on Organic Farming, Washington, D. C., 1980.

U.S. Environmental Protection Agency, Office

of Water Program Operations, Construction

Grants 1982 [CG-82), July 1982.

U.S. General Accounting Office, “Public Rangeland Improvement—A Slow, Costly Process in

Need of Alternate Funding, ” GAO/RCED-83-23,

1982.

Wood, J. E., Bickle, S., Evans, W., Germany, J.

C., and Howard, Jr., V. W,, “The Fort Stanton

Mule Deer Herd (Some Ecological and Life History Characteristics With Special Emphasis on

the Use of Water, ” New Mexico Agr. Exp. Sta.

Bu]l., No. 567, 1980.
Issues and

Options for Congress
Content s

Page

Treating Renewable Resources as Systems . . . . . . . . . . . . ““” ““””.. “ . . .“. “ . “ . . . . 333

Sustaining Long-Term productivity ~””.”. . . ” ” ” . ” ” ” ” ” .”””””.”” ..”.””..”. 341

Involving Uses in Decisionmaking . . . . . . ..”””...” ..”.”””Q.””””””..” ““””” 345
Chapter XII

Issues and Options for Congress

Federal support of Western water-resource

management and planning is critical for that

region’s agricultural and economic development. Most of the West’s water-resource problems are at least regional in scope and extremely difficult in nature, involving a complex web

of physical, chemical, biological, economic, legal, and sociopolitical issues. Often, they go

well-beyond the ability of a single Federal agency, State, university, or group of organizations

to address effectively. Although Western State

Governments have increased their role in this

area, they cannot, by themselves, handle all the

problems.

Because water does not remain within State

boundaries, water-related activities in one State

may have consequences beyond that State.

Strong Federal involvement under the Clean

Water Act continues to be needed to assure a

high quality of Western waters as they pass

through a river basin or an aquifer from one

State to another. Federal funding and support

in cost-sharing arrangements remains important for those regional water projects that require substantial investments, including those

related to rehabilitating existing projects.

Federal support for research in water resources

and water-resources management continues to

be needed to ensure that short- and long-range

national interests are served. In addition, longstanding Federal obligations in reserved water

rights, especially for Indian reservations, and

in international agreements involve issues that

require Federal attention. Finally, carefully

designed Federal incentives should still play

a role in helping States and individuals explore

and develop effective water management planning and equitable problem-solving of water-use conflicts.

Congress, however, cannot act alone to be

effective in this complex and diffuse area. Federal, State, and local governments are all involved with the regulation of Western water

for agricultural and other uses. This involvement affects and guides use and development

of water-related technologies for arid/semiarid

agriculture. The broad types of Federal tools

available to influence research and use of these

technologies include developing goals and priorities for Western water use and agriculture,

providing incentives, penalizing abuses, promoting improved management, equitably resolving conflicting claims and demands, and

providing more and improved information.

The following policy issues have been identified by OTA as those requiring congressional

attention and action over the next few years

to further the goal of sustainable agriculture

in the West. They are grouped in three major

categories (treating renewable resources as

systems, sustaining long-term productivity, and

involving users in decisionmaking) and are not

listed in any order of priority,

This major action area is divided into three

categories:

1. How Western scientists, water users, universities, and the public-at-large can play

an increased role in decisionmaking about

water and Western agriculture,

2. How congressional decisionmaking can be

strengthened.

333
334 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

3. How other Federal and State Government

agencies can improve specific programs.

Issue 1: The Need for an Interdisciplinary

Program of Basic and Applied

Research on Arid/Semiarid-Water

Resources

Federal attempts in the 1960’s and 1970’s to

build broad-based national programs in waterresources research and management through

the Water Resources Council and the Office of

Water Research and Technology were substantially reduced in the 1980’s. Awareness of

growing Western water problems has increased at a time when the Federal role in coordinating water-related research across the Nation has in large part been eliminated.

Many of the Nation’s universities have research programs on problems of water resources or water-resource management. Representing a wide variety of approaches and focuses depending on their funding priorities,

these programs involve a range of the natural

and social sciences and engineering, Frequently, agricultural departments within the landgrant schools utilize cooperative USDA-State

experiment station arrangements. Other universities outside the land-grant system or other

nonagricultural departments in land-grant

schools may conduct their work without cooperative USDA arrangements.

University programs related to water resources include biological and geochemical

research on water quality; studies of ground

water hydrogeology, recharge, and contamination; studies of wastewater treatment and

reuse; studies of weather modification; research on interbasin transfer and on more efficient use of water in agriculture; and studies

of the economic and legal aspects of water-resources management. These efforts include

laboratory and field research as well as theoretical studies. They entail use of any array of

field-measurement devices, computer modeling, or analytical instrumentation, or a combination of the three. They are housed in many

different departments, colleges, and institutes

of the universities, often appropriately in a

number of sites on a single campus, depending

on the focus and approach being pursued. All

such programs have at least one feature in common; they are all directed toward developing

new insight into the region’s and Nation’s

water supply.

However, the present situation lacks national

coherence. No mechanism exists for coordinating water-related basic and applied research

as it might apply to the wide range of waterresources problems in the U.S. arid/semiarid

lands. Often, links are not made to the broader

national or regional public policy relevance of

individual university research efforts.

A mechanism is needed that will focus the

multiplicity of university water-related

research approaches and disciplines on Western and national water problems. progress in

Western water-resources research, both basic

and applied, will benefit substantially by the

creation of a mechanism to focus and coordinate the talents of the Nation’s universities, the

research experiments of the innovative farmer

and rancher, and the resources of the

sector.

Option: Establish a National Center

Water Resources Research

Congress could establish a National

for Water Resources Research to provide a coherent and coordinated mechanism for the Nation’s university research programs in waterresources management for problem-solving

and policymaking, The mission of this center

could include:

private

for

Center

1. Undertaking an interdisciplinary program

of basic and applied research on water

resources and water-resource management. In addition to research in the natural

sciences and engineering, the program

should include a strong component of

basic and applied research in the social

sciences, such as resource economics and

law as they pertain to water-resources programs. The center could further assist in
.

2.

3.

4.

the conduct of site-specific research being

carried out under State auspices.

Developing and providing advanced and

sophisticated research facilities on a scale

required to cope with the broad nature of

water-resources problems, and often not

affordable by single universities, to be used

both by the resident staff, innovative producers, and university scientists.

Undertaking a program to develop and test

conventional and emerging technologies

for application to water-resources problems in U.S. arid/semiarid lands, including

application to problems of agriculture and

its sustainability in arid/semiarid lands,

and coordinating work with existing Government research by USDA and State agricultural experiment stations.

Serving as an objective, nonpartisan, and

continuing national source of information

for Congress when formulating public policy dealing with water resources, and as

a link to public agencies and to the private

sector for application of research findings.

The center could serve as a base for marshaling the talents of the Nation’s universities and

for augmenting, but not in any sense competing with, the work already underway in the universities. Its principal function could be to

enhance the effectiveness of water-resources

research and to focus the full competence of

the scientific community, private sector, and

innovative producer on problems of water

resources.

Using the example of the National Center for

Atmospheric Research (NCAR), an institution

created some 20 years ago by an act of Congress, the center could be managed and operated by a consortium of universities with

doctoral-level programs in water resources.

The member universities could elect a board

of trustees from member universities, industry,

user groups, and the community at large. The

board could be responsible for establishing

broad policy guidelines, for setting program

priorities and directions, and for overseeing the

center’s effective management. The operation

of the center could be directed by a scientist

Ch. X1l—issues and Options for Congress ● 335

.

appointed by and accountable to the board of

trustees,

Because a sustained effort is essential for

solving crucial water problems of the West and

the Nation, the funding support for the center

must be stable and long term. The principal

source of support for the center could be the

Federal Government, with supplemental support from the States and private sector,

An equally essential aspect for effective operation is that prime responsibility for program

initiatives reside with the consortium of universities managing the center. This requirement

is in sharp contrast with “Government-owned,

contractor-operated” laboratories where program initiatives often reside in the sponsoring,

mission-oriented Federal agency. This contrasting approach for the center is important

since the university community is closest to research for purposes of evaluating progress and

potentials. In light of this knowledge, plans

and priorities designed by the consortium

could take into account national, regional, and

State needs. Congressional and State agency

staff could be assigned periodically to the

center to translate research results for policymaking and update researchers on ongoing policy debates and issues.

For purposes of administration and funding,

the center could be operated by the university

consortium under a prime contract arrangement with a semiautonomous scientific agency such as the National Science Foundation

(NSF). Support from other Government agencies interested in water resources could be arranged through the single contract administered by the designated agency, The style

of research program management proposed

above is consistent with the research-overview

style and experience of NSF.

Issue 2: The Need for Congress to Have

Reliable Ongoing Information

About the State of the Nation’s

Renewable Natural Resources

OTA found that existing data available for

congressional decisionmaking is scattered
336 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

throughout the Federal Government in a variety of forms, These data were not collected with

the intention that each piece would be part of

an integrated and self-consistent base for Congress to use in making decisions affecting resource sustainability. Moreover, existing data

on components of the resource base on which

agriculture depends are seldom synthesized

because the data may be in noncompatible

forms and no single agency has had the ongoing responsibility to seek compatibility or

synthesis.

Congress needs improved information for

setting near- and long-term goals for sustainable use of Western water and agricultural

lands. This information should focus on congressional needs and emphasize systems analysis of data about renewable natural resources.

A recent Federal study about the analytical

capability of existing executive agencies to provide this long-term resource systems planning

capacity concluded:

. . . [E]ach agency has its own idiosyncratic

way of projecting the future, based on its own

responsibilities and interests. These different

approaches were never designed to be used as

part of an integrated, self-consistent system like

the “government’s global model. ” They were

designed by different people, at different times,

using different perspectives and methodologies, to meet different needs. While many are

widely recognized as making outstanding use

of state-of-the-art analytic procedures appropriate to their respective sectors, they produce

projections that are mutually inconsistent in

important ways. *

Ongoing analysis and synthesis of existing

data bases could provide improved information

on the dynamics of the resource system and

how interactions (natural and manipulated)

among resource components affect the sustainability of Western agriculture. Congress needs

improved information to understand:

1. the extent and quality of each resource

component,

—

* The Global zooo Report to the President, Technical Report,

vol, 2, 1980, p, 454; report was prepared by the Council on En-

\rironmental Qualit}. and the Department of State.

2. the amount and location of each resource

being used,

3. how quickly and where each resource is

replenished, and

4. how and what interactions among the

components affect the sustainability of the

system.

Option 1: Develop a special analytical

unit within the legislative

branch

Congress could develop a bipartisan unit

within the legislative branch with the principal

purpose to provide Congress with ongoing,

quantitative evaluations of the state of the

renewable natural resource system as a consequence of near- and long-term congressional

policies. The unit’s program should be interdisciplinary and multidisciplinary, with access to

state-of-the-art computer facilities to conduct

comprehensive data analysis and synthesis

from existing data sources on specific topics

requested by Congress, Such a unit could identify data gaps that are important to U.S. decisionmaking and that affect the sustainability

of the renewable resource base. It would require the independence and flexibility to obtain and interpret data in a nonbiased fashion

for the entire Congress. The following characteristics are important for this unit to function

successfully:

1.

2.

3.

4.

5.

6.

7.

8.

objectivity y;

bipartisanship;

ongoing capacity;

multidisciplinary and interdisciplinary

focus;

access to existing public data sources;

best available technology to analyze and

synthesize existing data quickly;

highly skilled specialists; and

a small, manageable size.

Specific organizational structure and legislative authority would have to be developed to

meet the unit’s defined purposes. The first step

in considering this option might be a workshop

of interested and involved congressional, executive, State, and local participants to examine

existing problems, the history of other experience in data synthesis, and possibilities for
Ch. XII—Issues and Options for Congress ● 337

—

action. This workshop might be combined with

the formation of a joint committee of members

from relevant House and Senate committees

to plan how to pursue and consider this option

further.

This option will require ongoing communications among the many branches of Government

to achieve an acceptable arrangement for

the new unit. Some individuals within Congress and the executive agencies may question

the value of such a unit for a number of reasons. In recent years, public concern has increased over the growing size of congressional

staffs. This unit, though small, could be so

criticized. Others may claim that existing agencies are competent and qualified to provide

Congress with the resource systems analytical

capability and that a small legislative unit will

require new funding at a time when funds are

in short supply.

Option 2: Establish an analytical unit

within the executive branch

Congress could develop an executive branch

unit as an alternative to that described in option 1 to provide ongoing quantitative evaluations for congressional decisionmaking affecting resource sustainability. On congressional

request, this unit could coordinate, integrate,

and interpret existing information-similar to

that proposed under option 1 for the legislative

unit-and report directly to Congress. Traditionally, Congress has turned to the executive

branch for answers to fundamental questions

involved with its policymaking. Existing executive branch agencies have personnel, equipment, and many data bases. Some career staff

have experience in aspects of water- and agricultural-data collection and analyses. At least

partial funding might be made available in the

executive branch through redirection of existing funds from lower priority activities, as

determined by Congress.

possible disadvantages of this option relate

to the ability of existing agencies to incorporate

this function and to the nature of executive

branch programs in general, as noted in the initial discussion of this issue. In recent years

Congress has found it necessary to develop

in-house expertise to supplement executive

branch input in areas requiring integration of

issues or verification and clarification of executive agency reports. Existing executive

agencies lack the analytical capacity for longterm resource systems planning. The placement of this particular unit in the executive

branch poses concerns about continuity. Programs and priorities in the executive branch

change with administrations. A small new executive unit is unlikely to be in a secure position to provide objectivity, coherence, and continuity, essential requirements for an effective

analytical unit. The current reduction in Federal support in water-resources planning and

research at a time when Western States are facing increased problems is only one example.

Currently, no existing executive agency has

the broad-based coverage of agriculture and

water required to meet the needs of this option.

Existing executive agencies commonly must

compete with one another for budget and program approval, especially where responsibilities are overlapping, as in the renewable resource areas. Any executive agency given the

task of providing ongoing quantitative evaluations for Congress about renewable resources

will require strong powers to obtain prompt

and ongoing cooperation from each agency

with potentially relevant data and expertise.

Issue 3: The Need to Integrate WaterRelated Agricultural Activities in

Government Agencies

The complex interrelated Western agricultural and resource problems of today require

an integrated approach to program research

and implementation. Generally, however, the

public sector agricultural and water-related

community is poorly prepared for the demands

currently being placed on it in arid/semiarid

agriculture.

Over the past few years, Federal reduction

in effort to integrate national water matters has

left the Nation with mission-oriented agencies

focused on their own particular responsibilities. Present Federal agencies in Western water
338 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

and agricultural-related activities have isolated

mandates and short-term remedies to parts of

the problem instead of pursuing research, data

analyses, and technological development with

a long-term view of the growing interdependency of all processes. For example, the U.S.

Geological Survey (USGS) has data on water

supply and quality, but not always in a form

available and useful for the more refined agricultural planning increasingly required in

water-short Western regions. The U.S. Department of Agriculture (USDA) may conduct research on a particular water-related technology without linking the design and results to

other important components of the onfarm

process; e.g., plant drought and stress factors,

soil-water management, or practices to reduce

nonpoint source agricultural pollution. The

Bureau of Reclamation storage and delivery

projects may work from an engineering perspective but may not be responsive to the growing needs of contemporary farmers for more

flexible and rapid adjustments to their water

deliveries in order to “save” water onfarm, The

National Weather Service may provide waterrelated forecasts in the West, but not in a context useful to the farmer who is planning cropwater requirements.

No longer can Western water-related agricultural problems be trusted to trial-and-error or

one-problem/one-solution procedures that have

been chiefly relied on in the past, Federal agencies charged with implementing congressional

policies and programs need an integrated coherent approach that minimizes confusion in

organizational responsibilities, and identifies

technological impacts as they affect various

components and ultimately the agricultural system and long-term productivity of the region,

The following options are specific areas conducive to immediate congressional action, and

all four are compatible with one another,

Option 1: Develop a USDA office of

resource coordination

Congress, through the hearing process, could

initiate discussions with USDA for the purpose

of designing and establishing a high-level office to integrate and provide coherence to water-related and agricultural activities within the

Department, This office of resource coordination should be placed at an appropriately high

level, for example, in the Office of the Secretary

of Agriculture, to ensure coordination and integration of activities among all specialized

agencies of the Department. The purpose of

this

1.

2,

3.

4.

5.

6.

office would be to:

analyze the various agency goals, priorities, and funding for any overlapping or

potentially conflicting activities related to

sustainable agriculture;

integrate the resource work of the various

agencies within USDA;

facilitate information exchange among

agencies;

work to develop consistency and reliability

among resource data bases of the various

agencies;

advise the Secretary on program adjustments to ensure that the Department operates with an integrated-systems approach

to agricultural research, technology development, and production; and

oversee the development and implementation of a systems perspective to specific

agency programs, such as that currently

in the planning stages within USDA’s

Agricultural Research Service.

The office could ensure that all departmental activities involving renewable natural resources are coordinated, alleviating the situation in which programs of one agency may

work at partial cross-purposes with those of another. An office located in the Secretary’s Office could emphasize the critical nature of agriculture’s natural resource base and make visible the role of the Department in protecting it.

It could encourage the Department to take advantage of the most modern systems-analysis

technology, technology that has not often been

used in agriculture.

Potential disadvantages exist with this option. An office of resource coordination within

USDA might become isolated from the operational activities of the Department unless careful procedures tie it to the action agencies. Its

role might vary widely among administrations,

making important responsibilities susceptible
Ch. XII—Issues and Options for Congress . 339

—

to political ideology, Some agencies might view

its activities as competitive with their own and

not be fully cooperative.

Option 2: Strengthen water focus of

Federal land-management

agencies

Congress could instruct the Federal land-management agencies responsible for Western

public lands to strengthen their focus on water

resources and water-resources management as

it affects agriculture, the primary Western

water user, pursuant to their multiple-use responsibilities. As part of this effort, increased

program attention could be paid to the mountain snowpack areas of the West, sources of significant surface water production for the entire region.

The multiple-use concept is already embodied in a number of Federal laws, including the

Multiple-Use, Sustained-Yield Act of 1960 and

the Federal Land Policy and Management Act

of 1976. Existing multiple-use statutory guidelines prohibit optimization of single, measurable resources (e. g., timber and cows) at the expense of less quantifiable uses (e.g., watershed

and recreation), and they forbid practices that

impair continuing land productivity. In recent

years, however, this mandate has often been

dismissed in preference for more single-purpose mandates aimed at revenue-producing activity. For the U.S. Forest Service, this focus

is principally timber production; for the Bureau

of Land Management, grazing. Decisions related to these single-purpose goals have left inadequate resources for the kinds of research

required to adequately take into account such

primary values as water in their resourcemanagement activities.

It is important that Congress take an increased interest in overseeing implementation

of the broad, multiple-use mandates of these

agencies. This option will entail a reorganization of agency priorities such that more emphasis is provided for long-term benefits from

water management and less emphasis is provided for short-term revenue-producing benefits from grazing and timber production. To ensure that water-management issues are adequately addressed, such tools as water impact

statements might be considered. Existing legislation might be strengthened, new legislation

might be added, or oversight might be more

earnestly focused on this increasingly important aspect of Federal public lands management—where possible, linking budget provisions to satisfactory performance.

An increase of focus on water resources by

Federal land-management agencies could lead

to a significant improvement in management

of water use on arid/semiarid lands, The primary water-producing areas in the West, the

mountain highlands, are on public lands. As

competition for available supplies increases,

Federal land-management agencies could play

an important role in designing and implementing long-term water-management programs for

the most effective use of water and in improving the knowledge of highland-lowland water

interactions for arid/semiarid agriculture.

There are several difficulties in strengthening the focus on public land water resources.

Federal agencies charged with this responsibility have no standards or defined priorities for

planning and integrating water projects within

multiple-use objectives. Multiple-use requires

tradeoffs, Some uses cannot be maximized in

a multiple-use system. A greater focus on water

may require adjustments in management plans

that result in some revenue reduction, from

timber and grazing activities, for example,

Moreover, a high proportion of agency personnel may lack the training and data needed in

hydrology to make the complex planning and

program decisions required to effectively integrate water into multiple-use programs. Finally, political influence and economic conditions have tended to set priorities favoring

timber and grazing, in spite of the multiple-use

mandates. Education of Federal administrators

and new thinking are required for the Federal

Government to appreciate the value of water

in the long-range planning of public lands for

arid/semiarid agriculture.
340 . Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

Option 3: Help States integrate waterresources data bases for systems

planning

Congress could provide technical assistance

and financial support to States for development

of computerized water-resources data bases. A

wide range of hydrologic data is presently being collected by various State agencies and

private industries as part of resource-monitoring programs (e. g., of mining sites). A

computerized data bank would make it possible for each State to store, retrieve, analyze, and

integrate a range of data not now being entered

into Federal data-storage systems, but increasingly needed for the depth of water planning

required at the regional, State, and local levels

for agricultural and nonagricultural purposes.

Such data bases could be designed to ensure

integration of water quality and quantity data

for water-resources planning. Federal funds to

States for water-resources planning and coordination could be allocated for State participation in this data system. The private sector

could share data and give advice on the best

available technology for data storage, retrieval,

and processing. Different States may need different levels of Federal technical support and

financial assistance to develop basic facilities.

Difficulties in data availability and use may

continue, even with the development of State

data banks, without some shift in other related

activities. For example, today in many Western

States water-quality and water-supply responsibilities are assigned to different entities. To

be effective, the development and ongoing use

of data banks at the State level may require increased coordination and cooperation among

the various State water-related agencies and increase in staff skilled in computer data storage

and retrieval.

Option 4: Expand mandates of Federal

agencies in instream flow

matters

Congress could expand the mandates of the

Federal agencies responsible for water-project

development and maintenance to take into account needs of instream flow, an area that has

had inadequate and, in recent years, reduced

attention at the Federal level. The agencies

could be directed to develop information and

operational procedures to identify and address

instream flow responsibilities and to be receptive to public concerns about instream flow issues. Coordination and consultation with other

Federal and State agencies on instream flow

matters could be systematized and intensified.

Instructive scientific and lay publications on

Western instream flow fluctuations and associated requirements to maintain the multiple

purposes of each river system in the West could

be an important aspect of these agencies’ expanded responsibilities for instream flow matters.

The maintenance of instream flows may

make it possible to maintain acceptable waterquality levels in some Western rivers without

the need for greatly increased water-treatment

facilities. An improved understanding of instream needs for the multiple purposes of Western river systems may also help improve management techniques to meet long-term requirements of hydroelectric generation and of

fish and wildlife habitat protection, Without

maintenance of some level of instream flow,

the quality of the river, in effect, becomes the

quality of return flows, which can often render a river unsuitable for subsequent uses without expensive treatment.

An increased Federal focus on the maintenance of instream flow requirements also

raises difficult issues. Traditionally the Federal

Government has deferred to the States on matters involving local water rights. In many U.S.

Western river systems, virtually the entire river

flow is already committed to various local offstream uses. If instream flow requirements are

to be met on these rivers, some existing offstream uses might have to be curtailed or

discontinued altogether in some of the most

severely water-short areas. Over the long term,

adjustments may prove the best approach

hydrologically and economically. Over the near

term, however, socioeconomic impacts may

occur during a period of transition that may

require special Federal assistance and atten-
Ch. Xl/—Issues and Options for Congress 341

— -—

tion to ensure that severe dislocations are min- cerned, the long-standing States’ interests in

imized. Federal involvement will raise all the local water rights and the broader geographic

difficulties inherent in trying to coordinate and and national interests of the Federa l

respect the two governmental systems con- Government.

SUSTAINING LONG-TERM PRODUCTIVITY

Issue : The Need for a Strong Federal

Role in Water Quality for

Sustainable Western Agriculture

water-quality issues require broad geographic perspective and strong involvement by the

Federal Government at a time when debate increases about the need to reduce Federal efforts in general. A strong national interest in

water quality is fundamental to protecting the

public health and environment in the arid/

semiarid West, The Western region, with

roughly one-third the volume of flow-through

water as that in the East, cannot absorb the

levels of industrial, municipal, and agricultural

pollution that the East can. Because agriculture

affects and is affected by water-quality degradation, the long-term economic development

of Western agriculture will hinge on a strong

national commitment to maintain high-quality

standards, support pollution controls, and

strengthen research efforts on the impacts of

water pollution on agricultural and nonagricultural users, A concerted, focused program of

water-quality maintenance and pollution control that involves the States is necessary.

The following options are compatible, and

all could be adopted by Congress,

Option 1: Make a firm commitment to

strong Federal water-quality

standards

Congress could maintain a firm commitment, particularly under the Clean Water Act,

to stringent national water-quality standards

for all uses. National standards are fundamental for long-term economic, environmental, and

public health protection of the Western States.

Stringent national water-qualit y standards

must be of high priority in order to protect the

range of present and future interests in water,

some of which require the highest standards

(e.g., for drinking water). Existing requirements

should be retained, and any new or revised water-quality standards should be made to enhance rather than degrade existing water

quality.

The West must be especially protective of its

water quality in view of the intensity of use and

reuse throughout the region and of the gaps in

knowledge about the complex interaction of

surface and ground water systems. Congress

could take special measures to minimize the

opportunity for exemptions or waivers to highquality water standards in the West. Even one

waiver could result in contamination of a river

basin or aquifer to such a degree that regional

and national interests could be jeopardized,

Without the maintenance of high national

standards, it is conceivable that agricultural

production in some areas may decrease or

cease because of water-quality degradation.

This situation could have major local and national implications, depending on the severity of the problem, for local economics, national

food production, and international trade. If

water-quality standard-setting were delegated

to the States, some upstream States might

lower standards, causing downstream users

the increased economic burden of absorbing

higher treatment costs before the water could

be used. National standards are needed to ensure that economic burdens and benefits are

evenly shared among States and to avoid industrial “shopping” for areas where water-qualit y

standards are lowest.

This option requires substantial commitment

of Federal, State, and local staff and finances,

all of which are becoming increasingly limited.

Monitoring and enforcement costs are involved as is increased research on the wide
342 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lana’s

— . —. ——

range of contaminants likely to be present from

time to time in Western water supplies.

Option 2: Implement nonpoint source

agricultural pollution controls

Progress toward implementing nonpoint

source agricultural pollution control programs

is essential for the same reasons strong waterquality controls are generally needed in the

West—the more concentrated contamination

possibilities with any pollutant. Congress could

revive national nonpoint source policy under

the Clean Water Act and particularly section

208, and actively support the accelerated implementation of controls on water pollution

from nonpoint agricultural sources where

problems are arising, This could include documenting and monitoring attempts and successes in controlling nonpoint source agricultural pollution. Current knowledge has identified some control measures useful for nonpoint

source pollution through the adoption of improved onfarm management practices. While

more research will improve such understanding for even better control, current opportunities exist to reduce such pollution. Some

of these practices may involve costs that are

difficult for economically disadvantaged farmers and ranchers to absorb over the near term.

However, such costs may be far outweighed

by long-term social benefits in reduced watertreatment costs and public health problems and

thus justify a Government role.

Because of limited resources, many States

now rely on voluntary action and cooperation

to achieve nonpoint pollution reduction. As

part of its commitment to control nonpoint

source pollution, Congress could direct that

Federal support to State and local efforts be

strengthened. Increased Federal support could

come in a number of forms, including technical

and financial assistance for training farmers

and ranchers to implement control measures,

providing incentives, and assisting economically depressed farmers to implement better practices. Federal grants to farmers might be made

contingent on farmers implementing known

procedures and methods, including “best

management practices, ” to reduce such nonpoint source pollution. Federal agencies already involved at the local level could increase

efforts to monitor agricultural runoff and assess methods of reducing nonpoint source agricultural pollution,

The disadvantages of this option relate principally to implementation uncertainties and

costs. To ensure adoption of “best management

practices, ” some economically disadvantaged

farmers may need technical and financial assistance to prevent the added costs from forcing them out of business. Additional resources,

including staff and funds, may be required to

implement the program and to enforce it

through surveillance and monitoring, Furthermore, to improve understanding and control

of nonpoint agricultural pollution, continued

research and analyses are needed on the hydrologic impacts of agricultural practices and

on improved methods of pollution control.

Option 3: Increase research and monitoring of agricultural and health

effects of contaminants in water

Congress could increase its support of research and monitoring on the short- and longterm agricultural and public health effects of

various contaminants in surface and ground

water, an area of research that is presently

fragmented and has few regional syntheses of

data. Present understanding of water-quality

conditions in the Western United States is

based largely on contaminant-specific local

studies, Little research, including that on

ground water contamination, has been undertaken on a comprehensive areawide basis or

on related health and environmental impacts,

Such research and monitoring could provide

valuable information for national policymaking to protect ground waters and surface waters from contamination. Existing standards

may not adequately protect the public in some

areas, while others may be too stringent. Once

contaminants and their long-term environmental and health effects are better understood,

water-quality standards can be adjusted accordingly. In view of the West’s low or sporadic

water-volume flows, the prudent approach is

to maintain high or stringent standards for both
Ch. X1l—issues and Options for Congress 343

. .-

surface and ground waters and to support high

levels of water-quality research to ensure longterm protection of public health and safety and

of the environment on which agriculture depends.

This option will require the support and assistance of all levels of government. Much of

the current information on specific contaminants and water-quality problems is with local

and State environmental protection agencies,

health departments, and universities. National

synthesis and analyses of existing data and a

strong national program of research will take

the time and talents of health and environmental specialists throughout the country. It may

be important to assist such efforts with funds

and support facilities through such means as

special grants administered by Federal agencies responsible for environmental or healthrelated matters. Duplication of effort may also

be a problem unless a national focal point for

coordination and information exchange can be

designated and supplied with the necessary

resources to function effectively.

Issue 2: Protecting and Maintaining the

Long-Term productivity of

Rain-Fed Agricultural Resources

Protecting the renewable resource base for

productive rain-fed agriculture in the arid/

semiarid West is a growing concern. Western

dryland and rangeland areas of the Great

Plains, the intermountain States, and the Southwest are important for rain-fed agricultural

purposes. Dryland farming sites represent

unique, global, soil/climate resources especially

suited for grain production. These areas are

vast; three times as much land is devoted to

dryland crop production in the West as to irrigated agriculture. Regional variations in

climate exist, but dryland areas share two features: 1) a limited and highly erratic supply of

water, and 2) a susceptibility to erosion. Sustainable agriculture in these areas must take

both into account.

Similarly, rangelands represent a substantial

Western land area and must be carefully

managed to maintain productivity. The problem of cultivating rangelands has become particularly critical in the semiarid lands of the

10 Great Plains States, where vast acreages of

grassland still exist, and in other States in the

West (e.g., California and Arizona), where the

land is particularly vulnerable to erosion. Such

areas are generally unsuited for cultivation because they are either too arid or on soils too

shallow or infertile to raise crops. Most rangelands are now in that category; they are unsuitable for cultivation but can produce, in an uncultivated state, forage for livestock and other

important services, such as habitat for wildlife.

Some Government programs currently carry

incentives that encourage cultivation of

arid/semiarid lands unsuited for cultivation but

agriculturally valuable as rangelands in their

natural state.

Maintaining and improving suitable rain-fed

agricultural systems could increase resource

productivity on vast amounts of U.S. land.

Dryland and rangeland agricultural systems

will likely increase in importance in view of

uncertain water supplies for irrigation.

Since the following two options are compatible, both could be adopted by Congress.

Option 1: Withdraw Federal incentives for

cultivation of Western lands

unsuited for cultivation

Congress could withdraw Federal incentives

that induce conversion of rangeland to cropland use where that use is not suitable for the

resource, One method of achieving this could

be to require that applicants for Federal

agricultural assistance certify that their land

is not new cropland or, if so, demonstrate that

a conservation plan approved by the local conservation district is in or will be in place for

the land put in production. The land-capability classes could be used as a guide for determining what lands are unsuited for cultivation

and, thus, ineligible for Federal assistance unless approved conservation measures ensure

that the land is not degraded.

Withdrawal of Federal incentives (e.g., price

supports, commodity loans, and disaster pay-
344 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands —

ments) for those producers who convert marginal lands to cropland would have little impact on conversion during periods of high-commodity prices since less Federal assistance

would be requested. Furthermore, withdrawal

would not “undo” the resource degradation

that has already occurred or may occur as a

result of inappropriate practices on such lands,

The option does not include provision for land

rehabilitation; thus, a speculator would not be

given the incentive to plow-up marginal lands

with the expectation that assistance will be

available for rehabilitation in the event of

severe erosion.

Concern may exist about the feasibility of implementing this option. Implementation problems could include the difficulty of developing

adequate conservation plans for those who

wish to convert rangeland to cropland. Additional staff and data may be required not only

to design adequate plans, but also to enforce

the plans and monitor compliance. Some sites

may not have had resource surveys; thus, information may be lacking on soil resources or

other related water- and environmental-data

needs that are important for making judgments

about the feasibility of cultivation. Finally, even

though the land-capability classification system

may be the best tool generally available, it has

many inadequacies, and questions exist about

its reliability for assessing land-conversion

issues. The National Association of Soil Conservation Districts, that has tried to address

some of these practical issues regarding implementation, maintains that the attempt is still

worth trying in view of the growing severity

of the conversion problem.

Option 2: Direct increased attention to

rain-fed agricultural technology

research and development

Congress could direct USDA to increase its

research and development focus on rain-fed

agricultural systems—both rangeland and dry

land. As Western water restrictions and costs

grow, irrigated production of grains and other

crops may decrease over time in many western

areas that can produce rain-fed crops. These

areas may be well suited to production of

stress-resistant varieties of conventional crops

and of other crops that are not now domesticated or widely grown. Significant opportunities exist to develop and expand dryland and

rangeland research into these broader areas of

focus. Moreover, many dryland and rangeland

areas could produce beyond their current capacities if a broader focus and strengthened

support were given to some of the long-term

opportunities of such technologies as waterconservation practices, land reclamation, integrated brush management, sophisticated

range management, and other biological techniques that are based on the strengths of the

natural systems.

One means of implementing this option

could be to convert some existing USDA field

stations specifically to facilities to test and

develop technologies, Such research and development could be part of an integrated resource approach to sustain or improve longterm productivity of rain-fed agriculture in U.S.

arid/semiarid lands, Congress could hold hearings with USDA to examine USDA’s existing

stations for the purpose of identifying those

facilities most appropriate for conversion. Research results could be made readily available

to ranchers and farmers through cooperation

with other USDA laboratories, State experiment stations, extension services, pilot projects, field-demonstration days, and exhibits for

the public. Grants might be provided to individual producers to test new technologies.

Cost-sharing arrangements could increase emphasis on innovative technologies.

Some may argue against this option, urging

that more and better crops for rain-fed agriculture may not be needed, However, that claim

is valid only if large quantitities of “new” water

become available to agriculture, an unlikely

possibility in the foreseeable future according

to the findings of this assessment. Others may

argue that rangeland research will be unnecessary because red-meat consumption may decline requiring less forage for livestock. Finally, resources devoted to potential new crops

adapted to low-water regions could decrease

those available for growing current commodity

crops.
Ch. XII—issues and Options for Congress ● 345

—— —

INVOLVING USES IN DECISIONMAKING

Issue I: Achieving Equity in Western

Water Availability and

Distribution

Lasting settlement of conflicts over water use

in the arid/semiarid West must involve principles of equity and fairness, The Federal Government, acting as public trustee for Federal

reserved water rights, is directly involved in

water-equity issues in the Western United

States, Without the application of equity principles in water distribution and development,

perceptions of unfairness will exist, and conflict and litigation, already problems of serious

proportions, will increase.

Water is security as well as opportunity in

the West, Because of water’s special properties as a dynamic renewable natural resource

and a fundamental social good, it has always

been subject to some public regulation to protect public interests. The practical application

of equity principles to protect the social value

of water has become a difficult test for contemporary institutions as rising demands have increased pressure on dwindling supplies. In

light of growing conflicts over use, the need

for Western institutions to ensure equity and

fairness in decisionmaking on water distribution and reallocation is a growing concern for

many users. It is especially worrisome for those

rightholders who may not have developed their

rights and for third parties who may be harmed

by shifts in resource use or by resource degradation.

Option: Assume leadership role in directly

addressing issues regarding

Federal reserved

water rights

Congress, in its leadership role under the

Federal reserved rights doctrine, could increase its efforts to address the complex and

long-term task of resolving issues surrounding

Indian reserved water rights and how they can

be protected in the future in view of increased

competition over water. In particular, two initial actions are appropriate, First, increased opportunity could be provided for negotiation

and ongoing representation of Indian interests

in both Houses of Congress. This might be accomplished through a variety of approaches,

including the initial appointment of a joint

House and Senate commitee or a special task

force to better define specific options for Congress, or the creation of a subcommittee on Indian affairs. Second, to protect reserved rights

where States have already fully appropriated

water, legislation could establish a mechanism

to remunerate or compensate reserved rightholders for water being used by others and to

provide for eventual reallocation of water to

reserved rightholders.

Because Congress has consistently left these

issues unresolved, piecemeal court decisions

have increased uncertainty for all parties, and

important Federal interests and economic investments have been threatened. In recent

years, pressures have grown (due to both nonIndian and Indian needs) to quantify present

and even future rights. Under the Federal doctrine of reserved water rights, Indians were

promised use of adequate supplies of water to

meet present needs and future opportunities.

By the very nature of the rights, society has

agreed to live with some uncertainty in order

to protect Indian homelands, so long as the

claims are reasonable. The Federal Government, as public trustee, has an obligation to

fulfill these agreements and promises. Congress could act to ensure that the Federal

Government adequately protects Indian interests by resolving issues surrounding reserved

water rights through the types of actions mentioned above. This will be an important step

in the effective long-term planning and development of sustainable Western agriculture,

Option 2: Establish a congressional

committee to oversee the

renewable natural resource

interests of disadvantaged

populations

Congress could establish a

tee on Disadvantaged People

Select Commitand Renewable

25-160 0 - 2 3 : QL 3
346 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

-— .— -. —

Resources to investigate and recommend legislation to protect the natural resource interests

of disadvantaged populations. A particular focus for Western disadvantaged people, especially poor farmers and Indians, could be their

relation to water resources. Among the topics

the committee could address is a mechanism

to educate these groups about their stake in

water management.

In addition, the committee could investigate

the possibility of legislation to help disadvantaged Western people form mechanisms to bargain collectively for Western water rights that

might be bought or sold in a market framework.

This kind of modification to “free” market

economics with respect to public properties of

water could help ensure that equity interests

are represented in large water-market transactions. For example, large energy companies

might choose to buy up major water rights.

This shift in water use could result in major

changes in economic patterns and in community life, along with severe dislocations for

many of the residents, including remaining

farmers. These changes may not be agreeable

to some community members. Where such

shifts are likely to precipitate community

change with major lifestyle implications, equity

principles would suggest everyone needs the

opportunity to participate in decisions about

how the water is to be used. The opportunity

to participate fully and fairly requires that information be made available on ways to pursue lifestyles in spite of change as well as ways

to participate in the transaction generating the

change.

Congressional action on this option and the

related prior option on Federal reserved rights

will be a challenge politically and administratively. Competent, sensitive staff, flexible and

creative negotiation, and a visibly strong national commitment will be required for a longterm effort if these complex areas are to be addressed effectively. Already, perceptions are

growing among poorer farmers and American

Indians that existing Western and Federal institutions responsible for water distribution

and development have not always treated them

fairly. Committed congressional action is

needed on both options to overcome conflict

and litigation, all of which will severely hinder

secure water-resources planning and management for sustainable Western agriculture,

Issue 2: Understanding the Impacts of

Water Pricing on the Adoption

of Technology

Farmers and ranchers respond to economic

conditions in their attempts to become efficient. Federal subsidies have lowered the cost

of water for many Western users. When water

is inexpensive, the use of large amounts of

water may be efficient from the user’s point of

view but not from society’s point of view, since

society (the subsidizer) is paying for some of

the individual’s costs. Although farmers and

ranchers have adopted more efficient technologies in recent years, they have done so generally for reasons other than water conservation, usually to reduce energy or labor costs.

Water conservation, when it has occurred, has

been a secondary benefit in most areas.

Existing Federal water-project repayment

laws and policies are receiving increased attention and study. Reforms being proposed in

both the legislative and executive branches include more equitable cost-sharing arrangements and greater cost recovery from the water

users. Such reforms will have the effect of helping move the cost of water to a level more reflective of its scarcity value.

As the cost of water increases, some agricultural users may find it economically profitable

to transfer (sell or rent) their water rights,

especially those senior rights that may attract

a high market value. Other agricultural users

may adopt more efficient water-use practices

to reduce total input costs, in view of higher

water prices, and remain a profitable operation. The price of water in a water market may

be affected by Federal action with water subsidies insofar as those subsidies affect the quantity of available water.

The short- and long-term consequences of

greater market activity in Western water are

matters of lively debate and growing concern,

especially for some Western farmers. Water is
Ch. Xl/—Issues and Options for Congress ● 347

—

a resource with physical characteristics and social value not suited to a pure market situation.

Transfers of major upstream water rights could

conceivably have hydrologic and economic

consequences downstream. Moreover, questions exist about the desirability from a national

standpoint of allowing water markets to develop without some measures to assure that existing agricultural users are not severely

harmed and that long-term public welfare is

benefited.

Option: Evaluate the impacts of water

markets on agriculture and related

economies

Congress could seek the assistance of the

Congressional Budget Office (CBO) in a study

of the short- and long-term economic impacts

of reduced water subsidies and increased

water-market activity on Western agricultural

users and nonfarm economics. A CBO analysis

can help Congress: 1) understand the possible

near- and long-term economic consequences

of reforming water-project repayment plans

and programs for Western agriculture and nonfarm economies; and 2] provide guidance,

monitoring, and assistance with the transition

to greater use of water markets to the extent

that is likely to result from reduced development subsidies. Although scattered studies are

beginning to appear on the economics of water

in the West, CBO could provide an objective,

comprehensive synthesis of available socioeconomic information and a focused analysis

of the Federal connection with the economics

of Western water and agricultural practices.

Over the near term, an easier solution might

be to allow the existing situation to continue.

Gradually, however, water-related problems aggravated by competing demands will probably

increase. Actions such as this option may help

Congress deal with the changes likely to occur

because of water-subsidy reform, particularly

those changes in Western agriculture and in

nonfarm economies affected by Western agriculture,

Issue 3: Improving the Effectiveness of

Water-Related Technologies for

Sustainable Agriculture

The bulk of current knowledge about the potential of existing and new technologies to contribute to a sustainable Western agriculture is

from site-specific studies. These studies have

led to the formulation of technological principles that may have general applicability. However, judgments about the potential of specific

water-related technologies for sustaining arid/

semiarid agriculture in the Western United

States are difficult to make from these sitespecific data. A principal reason for this is that

the effective application of specific technologies depends on the ability of the researcher

and user to adapt them to local conditions.

Moreover, the researcher’s perspective about

effectiveness may vary from the user’s perspective; the former may be looking at technical efficiency, while the latter may be interested in

economic efficiency. Research for both onsite

and offsite technologies suffers from questions

of relevance and practicality for a particular

agricultural site and user.

Option: Provide mechanisms for increased

researcher/user interaction

Congress could direct USDA and the Federal land-management agencies to establish useroversight groups for their research activities

in two particular areas. One user-advisory

group could focus specifically on the onsite water-conserving technology needs of arid/semiarid agricultural producers and provide advice

and oversight principal}’ to USDA. Particular

emphasis could be placed on identifying and

using innovative producers representing the

variety of agricultural systems in the West,

Local agricultural organizations could be

useful sources of information to identify the

most innovative producers.

A second user-advisory group could focus

specifically on the usefulness of offsite wateraugmentation technologies for downstream
348 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands — --

agriculture. This user group could be comprised of innovative producers who are directly

downstream from the experimental water-producing sites. The group could advise and oversee those Federal agencies responsible for water-related technologies that are applied upstream or in highland areas offsite from arid/

semiarid agriculture but have potential waterrelated impacts for that agriculture (e. g.,

weather modification, watershed management,

snowmelt forecasting), The linkage between researcher and user is particularly important

with such water-augmentation technologies because resource manipulation often occurs

some distance from the point of potential agricultural impact. A user-advisory group could

provide researchers with the increased opportunity to understand downstream needs of water timing, quality, and quantity.

These user-advisory groups could report to

heads of agencies and to Congress. They could

provide the much needed perspective of the

people who ultimately use the products of

research. Such an approach could mimic the

highly successful Israeli system in which agricultural researchers engage in farming and

equipment manufacture as well as laboratory

work. In view of the site-specific effectiveness

of water-related technologies and of the focus

of much of the Federal water-related research

work in arid/semiarid lands, improved agricultural user-researcher communication could

provide guidance to Federal agencies about

priority areas for action. User groups could

assist Congress in determining whether Federal resources in these areas are producing

results that justify continued Federal support

or whether a refinement in focus and programs

is appropriate.

Concerns about this option relate to the possible effectiveness of the user groups, At present, a National Agricultural Research and Extension Users Advisory Board (UAB) exists

pursuant to legislation in the Food and Agriculture Act of 1977. A recent OTA report on

the U.S. food and agricultural research system

found this board’s effect on USDA research priorities to be unclear. Other concerns are that

researchers who interact with user groups

would be taking time that might be spent otherwise with laboratory or field work. Moreover,

the focus of particular users might be on shortterm economic solutions rather than longrange issues involved with the development of

technologies for sustainable agriculture.

In light of these concerns, the task will be to

define carefully and succinctly the composition and functions of the Western user-advisory

groups proposed by this option. Precautions

will be needed to ensure that such groups effectively represent Western users and have the

capacity to evaluate and examine objectively

the work of the Federal agencies. Congress

could require that users be nominated by representative agricultural organizations and have

access, when needed, to scientific expertise

independent of that of the Federal agencies.
Appendixes
Appendix A

Features of the Arid and

Semiarid Region

Note: The information in this appendix further elaborates on material presented in chapter II.

Natural Features of the Arid and

Semiarid Region

The Great PIains

The Great Plains stretch eastward from the Rocky

Mountains to the Midwestern United States in a

band 300 to 400 miles wide and extend north and

south from Canada to the Gulf of Mexico. The region features comparatively level, broad expanses

of land that are, for the most part, easily traversed

and readily habitable.

The climate of the Great Plains is highly variable,

and its weather is known for extremes. Average annual precipitation generally increases from west to

east and from north to south; greatest amounts occur during the spring and early summer. Amounts

fluctuate widely between years and months but generally range from about 25 inches in southern Texas

to less than 12 inches in the northern part of the

plains. Snow accounts for 20 to 30 percent of the

annual precipitation in the central and northern

areas of the region. Another apparent characteristic

of precipitation is a tendency for a number of

below- and above-average precipitation years to occur together.

Temperatures in the Plains tend to increase as

one moves south. In the northern Great Plains,

mean monthly temperatures for January and July

are 50 and 700

F, respectively. In the south, average

temperatures for these months are 40- and 80” F.

Winter temperatures of –60 F and summer

temperatures as high as 120- F have been reported.

The length of the frost-free period ranges from

about 100 days in the north to over 200 days in the

south.

Wind is a prominent feature of the Great Plains.

Over most of the area, average wind velocity is 10

miles per hour. However, in the winter and early

spring, the region often experiences strong winds

of 30 to 60 milcs per hour that are sometimes accompanied by snow. The winds that occur during

and after these storms may last for several days and

cause severe soil erosion as well as damage to vegetation, livestock, and buildings.

Soil characteristics in the region vary widely,

reflecting differences in parent sources, topography, climate, and plant and animal life. In

general, soils of the Plains region are relatively fertile, moderate to low in organic matter, and susceptible to wind and water erosion. In poorly drained

areas, soils are subject to salinization.

The plants and animals of the Great Plains vary

along both the east-west and north-south gradients

of precipitation and temperature. In the east, most

of the region was originally covered by lush, tall

grass, characterized by deep roots and vigorous

growth. In the western part, where precipitation

is lower, short grasses dominate. The short grasses

form a dense sod, and their roots do not penetrate

the soil deeply. Herbs also grow in the short grass

region, Between the tall grass and short grass regions is a mixed area, composed of midgrasses and

short grasses. Both kinds of grasses are intermixed

and occur equally—mid-grasses form the upper

layer of vegetation, and short grasses and sedges

form the lower one. Woody vegetation in the grassland region occurs rarely under natural conditions, except in low areas and along rivers and

streams. Pronghorn antelope, mule and white-tailed

deer, jackrabbits, and other rodents are common

throughout the region. Across the southern part

of the Great Plains, grasses are mixed with shrubs

and low trees. The northern boundary of these

brushlands coincides with the northern distribution

of several mammals—e.g., the Mexican ground

squirrel and the gray fox.

The Interior Basin extends almost to the Canadian border in the north and to Arizona and New

Mexico in the south. On the east, the region is

bounded by the Rockies; the western and northern

border is formed by the Cascade and Sierra Nevada

Mountains. Relatively high elevations and level

land surfaces characterize the area, but some regions are dissected by rivers or interrupted by small

mountain chains. Some of the area consists of separate interior basins without drainage to the sea.

351
352 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

—.. —— -——. ..— —— -

A variety of weather patterns occurs within the

Interior Basin because of differences in topography,

latitude, and elevation. The region is characterized

by low and erratic precipitation. Average annual

precipitation ranges from O to 48 inches at the tops

of mountains. Most of the moisture comes as snow

in the winter months.

Temperatures in the Interior Basin are like those

of other continental climates. Both daily and seasonal temperatures range widely and reach extreme

highs and lows. In the north, average monthly

temperatures for January and July are 300 and 600

F. To the south, average temperatures are 350 and

800 F. Subzero winter temperatures in the mountains and summer temperatures over 100° F in

southern valleys are common, The frost-free period

varies from less than 60 days in high mountain valleys to over 200 days in southern lowland valleys.

Like the Great Plains, the northern part of the Interior Basin experiences strong winds in the winter

and early spring as storms move across the area.

Winds in the southern region tend to be from the

south, and wind speeds are usually light to moderate,

Soils of the northernmost part of the Interior

Basin developed in thick wind-blown deposits,

sometimes mixed with volcanic ash. These soils are

generally deep, fertile, and fine-textured, but prone

to severe water erosion. Over much of the rest of

the region, soils formed in residual materials. Salt

flats and playas (the level floors of undrained basins

that, at times, may become shallow lakes) are extensive in some areas and contain thick accumulations

of alkaline and saline salts.

Vegetation in the region varies widely. In general,

the broad valleys in the lower portion of the basin

are covered by low shrubs. Almost pure stands of

some shrubs occur, and many of them tolerate high

alkali and salt concentrations in the soil. The lower

elevations of the mountains and foothills in the area

are usually covered by big sagebrush and grass, or

by a combination of various low, shrubby, woody

species. The mountains of the area support complex vegetation with a number of different plant

communities, varying from low shrubs in the foothills, to trees at higher elevations, and grasses above

timberline.

For the most part, the animals in this region are

similar to those found in other areas. Wildlife

species are especially important because of the

wilderness character of the region. The area is also

an important breeding and resting ground for migrating birds.

The Central Valley of California

To the west and south of the Sierra Nevada and

Cascade mountain ranges and east of the Coast

range is the Central Valley of California. The Central Valley constitutes two major river basins, that

of the Sacramento River on the north and the San

Joaquin River on the south. These two rivers flow

toward each other and join in the Sacramento-San

Joaquin delta. The combined basins extend nearly

500 miles in a northwest-southeast direction and

average about 120 miles in width. They include

more than one-third of California.

Generally, the climate of the Central Valley is

mild. Most precipitation occurs in the fall and

winter. Annual amounts tend to be higher in the

north than in the south and range from 22 inches

in the northern Sacramento Valley to 6 inches in

the southern San Joaquin Valley.

Precipitation and resulting runoff vary not only

from winter to summer of each year, but also in

total annual amount in different years, For example, in extremely dry years, the runoff may be as

little as one-third to one-tenth the average annual

runoff, In extremely wet years, extensive flooding

may be caused by runoff which may be two to over

three times the average. Moreover, a succession of

dry or wet years often occurs,

Temperatures in the Central Valley increase from

north to south. Summers are hot and winters are

mild. The average temperature for January is 450

F and the average for July is 7 0

o F. The frost-free

period ranges from 260 to 300 days.

Soils of the Central Valley formed on a variety

of parent material, and properties vary. Generally,

however, the soils developed on fertile alluvial deposits and are deep and fine-textured. In low areas,

drainage may be poor and alkaline and saline salts

may accumulate.

Evidence indicates that the Central Valley of California was once dominated by annual grasses, Today, many of these grasses have been eliminated

by cultivation, fire, and grazing. Similarly, some

animals such as the tule elk, pronghorn antelope,

and feral horse and pig have disappeared from the

valley and are confined to higher elevations, Now,

deer, rabbits and other rodents, quail, wild turkeys,

and partridges are common,

The southwest

The Southwest includes areas in southern California, southern Nevada, southwest Utah, Arizona,
App. A —Natural Features of the Arid and Semiarid Region ● 353

— .

southern New Mexico, and southwest Texas. The

region is characterized by a broad spectrum of landscapes, including mountains, valleys, plains, and

canyons.

The climate of the Southwest is arid, with hot

summers and mild winters. Annual amounts of precipitation range from O inches to less than 16 inches. Most occurs during the summer months. Average temperatures range from 450 F in January to

85 F in July. Summer temperatures exceeding

100 r F occur frequently. The frost-free period

varies from 210 to 365 days in the southernmost

part of the region.

Soils in the Southwest are variable. Generally,

they formed in residual material and tend to be

shallow and coarse in texture, although some are

fine-textured and well-developed. In some areas,

gravel and bare rock appear on the surface because

intense desert storms remove soil accumulations.

Salt flats and playas occur in low depressions with

no exterior drainage.

Two large deserts occupy much of the area. The

deserts of California and Arizona are characterized

by large treeform cacti and numerous woody

shrubs. These plants provide little groundcover,

and small annual plants carpet the ground only

after rare and heavy rainstorms. Although large

animals are almost absent, small nocturnal burrowers such as rats and mice are common, To the

east, the deserts of New Mexico and Texas are

characterized by thorny scrub vegetation in open

stands or thickets. Short grasses provide forage for

pronghorn antelope, deer, and numerous rodents.

Cash Receipts From Farm Marketing,

17 Western States, 1980’

Agricultural product

(million dollars]

State

Great Plains:

Texas . . . ., ., . . . .

Nebraska .

Kansas . . ... ...

Oklahoma . . . . . . . . .

South Dakota ... ,

North Dakota . . . . . . .

Mountain region:

Colorado . . . . . . . . . . . .

Idaho ., ., ., . .

Arizona ., ... , . . . . .

Montana ... . .

New Mexico . . . . .

Wyoming . . . . . ...

Utah . . . . ... , ...

Nevada . . . . . . . . . . . .

Pacific region:

California ... , . . ., .,

Washington ... . .

Oregon . . ... . .

Total, Ii’ Western States

Total, United States ... ,

Livestoc k

and products Crop s

5,920

3,873

3,355

1,986

1,710

662

2,499

907

864

727

850

572

376

150

4,452

807

621

30,281

69,209

4,114

2,569

2,586

1,148

723

1,656

927

1,085

1,036

651

273

110

124

65

9,210

1,807

973

29,058

68,806

Tota l

10,034

6,442

5,941

3,134

2,433

2,318

3,376

1,992

1,900

1,378

1,123

682

500

215

13,662

2,614

1,594

59,339

138,015
354 . Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid

—...—- — —

Agricultural Exports in the 17 Western

States, by State, October-September,

1979-80 and 1980-81

Lands

—

— Total Total

agricultural agricultural

exports (million exports Million

State dollars) Leading exports * State dollars) Leading exports*

Great Plains:

—

New Mexico: Wheat, teed grains

Texas:

1980 ., . ,

1981 ., ... .,

Kansas:

1980 ... , .,

1981 .,

Nebraska:

1980 . .

1981 . .

North Dakot a

198 0

1981 ...

Oklahoma:

1980 ...

1981 .,

South Dakota:

1980 ., ...

1981 . ,

Mountain region:

Colorado:

198 0

1981 . . .

Idaho:

1980 . ., ...

198 1

Montana:

1980 . ,

198 1

Arlzon a

1980 ...

1981 . . .

2,976

2,577

2,085

2,263

1,873

2,114

1,435

1,144

1,003

931

697

708

534

780

467

634

474

513

439

488

Cotton, feedl grain

wheat, rice, animals,

and meat

Wheat, feed grains,

soybeans, animals and

meat, fats and oils

Feed grains, wheat,

soybeans, animals and

meat, fats and oils

Wheat, sunflower seeds

and oil, feed grains,

seeds, feed and fodder

Wheat, cotton, animals

and meat, fats and oils,

hides and skins

Wheat, feed grains,

soybeans, sun flower

seeds and oil

Wheat, feed grains,

an i reals and meat, seeds,

hides and skins,

vegetables

Wheat, vegetables, feed

grains, seeds, hides

and skins

Wheat, feed grains,

animals and meat, fats

and oils

Cotton, wheat, fruits,

cottonseed, an i reals and

meat

1980 . , 139

1981 . . . . 151

Utah:

198 0 104

1981 ., ., 114

Wyoming:

1980 . . . . 76

1981 ... ... 94

Nevada:

198 0 23

1981 . . . . . 25

Pacific region:

California:

1980 . . 3,253

1981 ., 3,589

Washington:

1980 ... . . . 699

1981 ., ., . 1,018

Oregon:

1980 . . 385

1981 ... . . 513

Total, 17 Western States:

1980 ... . . . . . . 16,662

1981 . . ., ... . 17,656

Total, United States:

1980 . ., ., 40,481

1981 ., ., ., . 43,789

17 Western States, percent

of total U. S.:

1980 . ... 41

1981 . . . 40

cotton, animals and

meat, fats and oils

Hides and skins, wheat,

animals and meats, feed

grains

Wheat, animals and

meat, hides and skins,

fats and oils

Animals and meat,

hides and skins, fats

and oils

Fruits, nuts, cotton

vegetables, wheat

Wheat, vegetables,

fruits, seeds, hides

and skins

Wheat, vegetables,

seeds, hides and skins,

animals and meat

—

Appendix A References

1. Bailey, R. G., Description of the Ecoregions of the 3

United States. U.S. Department of Agriculture ,

Miscellaneous Publication No. 1391, 1980.

2. Brengle, K. G., Principles and Practices of Druyland

Farming [Boulder, Colo.: Colorado Associated University Press, 1982).

Ferguson, Hayden, Lyle, William, Fenster, Charles,

and Wendt, Charles, “Dryland Agriculture, ” OTA, unpublished draft report, August 1982.
Western Regional Water

Appendix B

Characteristics

NOTE: This appendix presents in more detail the data on which chapters III and X have been

based. The data are presented primarily in graphical and tabular form, designed generally

to supplement the discussion of the water supply/use relationships of the Western United

States with specific data or discussions related to each of the surface- and ground-water resource regions of the area. The main source for the surface water section of this appendix

is the Second National Water Assessment (5). One of the primary difficulties in assessing

a water-related problem in the Western United States today lies in the often incompatible

data bases used to describe water supply/demand relationships in the region. Where such

discrepancies are noted in this appendix, the reader is referred to the original publications

from which the data were obtained.

The Water Resources Regions of the Western United States With Water

Supply/Use Patterns for Selected Subregions

The fundamental hydrologic unit is the river

basin. The United States was subdivided into 21

major water geographic units based on river basins

in 1970 by the U.S. Water Resources Council. Hydrologic data are collected and organized according

to these units, which are: 1) regions, 2) subregions,

3) accounting units, and 4) cataloging units. These

hydrologic areas contain either the drainage area

of a major river, such as the Missouri region, or the

combined drainage areas of a series of rivers, such

as the Texas-Gulf region. The second level of classification, the subregion, contains either an area

drained by a river system, a reach of a river and

its tributaries in that reach, a closed basin, or a

group of streams forming a coastal drainage area.

All subregional boundaries are hydrologic except

where discontinued at international boundaries.

For the purposes of this discussion, only the region

and subregion categories will be used. The subregion classification is that used in the Second National Water Assessment (5). This differs somewhat

from the accounting units of the USGS which are

also hydrologically defined.

The 17 Western States have been divided into

nine water resources regions, containing 52 subregions (fig. B-l). There are wide variations among

these water resources regions in the spatial and

temporal availability of water and in the uses of that

water (figs. B-2, B-3, B-4, B-5).

355
356 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

Figure B-1 .—Water Resources Regions and Subregions of the Arid and Semiarid Portions

‘of the United States

10

Missouri region

--- -. - --- . - -+

*-=- .- . —. . —.

These are the subdivisions used by WRC in the Second National Water Assessment. The subregions do not correspond

to those used by USGS.

SOURCE U.S Water Resources Council, The Nation Water Resources 1975-2000 (Washington, D.C U S Government Printing Office, 1978).
App. B—Western Regional Water Characteristics ● 357

.- .—

Figure B-2.— Total Off stream Water Withdrawals by States and Water

Resources Regions, 1980

A State s

B Water-resources regions

SOURCE W Solley, E Chase, and W Mann IV, Estimated Use of Wafer in the United States in 1980, U S. Geological Survey Circular 1001, 1983.
358 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

Figure B.3.—Freshwater Consumptive Use, by State and Water Resources Regions, 1980

25

26

24

25

SOURCE W. Solley, E. Chase, and W. Mann IV, Estimated Use of Water in the United States in 1980, U.S. Geological Survey

Explanation

Percentage

Range of total U.S.

(bgd) consumptive use

O-6 4 25

65-11.9 23

120-169 28

170-250 24

Circular 1001, 1983
App. B—Western Regional Water Characteristics c 359

— .

Figure B“4.— Withdrawals for Off stream Use From Ground and Surface Water Sources,

by States and Water Resources Regions, 1980

11. States

I I

Withdrawals

Iiil

SOURCE W Solley, E Chase, and W Mann IV, Estimated Use of Water in the United States In 1980 U S Geological Survey Circular 1001, 1983
SOURCE: W Solley, E. Chase, and W. Mann IV, Estimated Use of Water in the United States in 1980, US. Geological Survey Circular 1001, 1983.
Water-Region Maps

25-160 0 - 24 : QL 3
362 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands — .— -. — --

The Missouri River Basin: Water Resources Region 10

The Missouri River Basin—including portions of The relationship between water availabi

. .

ity and

Montana, Wyoming, Colorado, North and South

Dakota, Nebraska, and Kansas—contains one-sixth

the land area of the 48 contiguous States, about

511,309 square miles (mi 2

). Estimates of annual

runoff range from 49,4 million acre-feet (maf) (5)

to 60,5 maf (4). There are six large constructed

reservoirs on the Missouri mainstem and these, together with tributary reservoirs, have a normal storage capacity of slightly more than 83 maf. This storage capacity is approximately 1.7 times the mean

annual flow. Total withdrawals of water for all uses

is approximately 43 maf, one-half of normal storage. Withdrawals for irrigation are slightly more

than 35 maf, or 81 percent of all withdrawals. Fortyone percent of all water withdrawn is consumed,

the majority for irrigated agriculture.

water use varies greatly within this region. As can

be seen in figure B-6, in general there is a surplus

of water over demand in the northern States of

Montana and North and South Dakota, while the

southern States in the basin—Colorado, Nebraska,

and Kansas—use all of the available surface water

and make up the deficit between supply and use

by extracting water from ground water aquifers

during the period of deficit. The extent to which

current levels of water use can be sustained will

largely be determined by the availability of ground

water reserves. Without some shift in water use patterns, it is apparent that existing surface water resources are totally committed in the southern portion of the basin.

Water Resources Region 10: Missouri River

The relationship between water supply and use by month for selected subregions of the Missouri River Basin. While there is an

excess of supply over demand during all months in the northern sections of this basin, most subregions in the southern parts experience a water supply shortage during the summer months when use is at the annual maximum.

-. — — —

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption

Subregion

to total

(mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1001 . . . . . . . . 5,910 134 22 1 82 923 318 230/o

1002 . . . . . . . . 4,770 1,373 59 0 230 4,376 1,315 22

1003 . . . . . . . . 5,530 5,081 11 1 545 335 150 21

1004 . . ., 7,760 1,017 165 7 203 7,306 2,086 21

1005 . . . . . . . . 14,200 14,415 179 10 2,186 1,145 512 24

1006 . . . . . . . . 16,500 191 177 13 134 244 180 22

1007 . . . . . . . . 1,020 2,474 1,849 435 366 8,825 3,314 85

1008 . . . . . . 3,920 153 2,996 450 134 5,477 3,346 69

1009 . . . . . . . . 24,800 36 288 30 12 2,084 186 32

1010 . . . . . . . . 3,910 931 4,432 1,600 842 5,808 3,866 63

1o11 . . . . . . . . 44,100 1,536 229 10 190 1,493 196 27

Total region . . 44,100 27,161 10,407 2,557 4,924 38,016 15,469

Key mgd = million gallons per day (multiply by 1,120 to obtain acre-f t/year) bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App. B—Western Regional Water Characteristics . 363

— — — — —— — —— -

Figure B-6.—The Missouri Water Resources Region

5

D

I I

I

1001,1002,1003

20

15 [

40

30

10

1007

North and

South Platte

Month

1007 + 1008

)
364 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

— —

The Arkansas, White, and Red River Basins: Water Resources Region 11

The Arkansas-White-Red region covers about

244,000 mi2

, 7 percent of the Nation. It lies in the

south-central portion of the United States between

the Continental Divide and the Mississippi River.

Three major rivers—the Arkansas, White, and

Red—drain the region, which includes all of Oklahoma and parts of Colorado, New Mexico, Kansas,

Missouri, Arkansas, Texas, and Louisiana. It has

been included in the present assessment because

much of the basin lies in the southern Great Plains

region of the Western United States.

The total surface flow from the region in an

average year is estimated at 70.1 maf (5) and 81.8

maf (4). Normal storage in reservoirs in the region

is 30.3 maf, or approximately 45 percent of the

mean annual streamflow of the region. Total withdrawals for all uses in 1975 were 14.4 maf, of which

11.2 maf, or 78 percent, were withdrawn for irrigation. Sixty-three percent of all water withdrawn is

consumed, the majority (88 percent) by irrigated

agriculture.

Water supply and use relationships, which are illustrated graphically for various selected subregions within the basin in figure B-7, vary widely,

both spatially and temporally, throughout this basin. Headwaters subregions, as represented by

1102, the upper Arkansas River, have a high apparent excess of supply. The intermediate reaches

of the Arkansas and Red Rivers, in portions of Kansas, Oklahoma, and Texas, experience periods of

2 months (July-August) when demands made on the

surface water resources exceed the supply, while

in the lower reaches of these same rivers, in eastern

Oklahoma and Texas, supply generally exceeds use.

The deficit in supply in the middle reaches of the

Arkansas and Red Rivers has been met by overdrafting the Ogallala aquifer, which is now showing signs of depletion in portions of this area. Here,

water-use patterns and trends will have to be modified if a balance between available water supplies

and water uses is to be achieved.

Water Resources Region 11: Arkansas-White. Red Rivers

Water supply and use for the Arkansas-White-Red water resources region. Natural supply exceeds the demand during the winter

months in the region as a whole. However, during the summer months when agricultural use is at its peak, water use either exceeds

supply or approaches it very closely in most subregions.

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Offstream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1001 . . . . . . . . 15,900 3,477 301 2 0 196 96 1 %

1002 . . . . . . . . 155 416 217 21 126 1,800 743 85

1003 . . . . . . . . 4,280 198 3,619 2,098 547 3,456 2,031 56

1004 . . . . . . . . 27,000 2,107 150 6 203 1,024 299 19

1005 . . . . . . . . 3,540 1,466 2,805 2,069 659 3,168 2,440 62

1006 . . . . . . . . 2,320 1,473 1,647 1,259 1,007 2,746 2,276 68

1007 . . . . . . . . 1,970 736 107 2 73 478 179 12

Total region . . 62,600 9,853 8,646 5,457 2,615 12,868 ‘8,064

Key: mgd = million gallons per day (multiply by 1,120 to obtain acre-ft/year) bg = billion gallons (multiply by 3,070 to obtain million acre-f t).

SOURCE: Second National Water Assessment, 1978.
.

App. B—Western Regional Water Characteristics ● 365

— . — — .——. —

Figure B-7.—The Arkansas-White-Red Water Resources Region

Month

SOURCE Second National Water Assessment
366 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

The Texas-Gulf Basins: Water Resources Region 12

The Texas-Gulf region extends from the Gulf of

Mexico northwest for some 650 miles into the

southern Great Plains, Almost all of the region (94

percent) lies within the State of Texas, although

small portions of Louisiana (1 percent] and New

Mexico (5 percent) are included, The total surface

area of the region is about 177,700 mi2

, approximately 5 percent of the total surface area of the Nation. The region consists of the drainage areas of

the Sabine, Neches, Trinity, San Jacinto Brazes,

Colorado, Lavaca, Guadalupe, San Antonio, and

Nueces Rivers. These rivers drain in a general

southeasterly course to the Gulf of Mexico. The

total streamflow from the region during an average

year is estimated to be 31.7 maf (5) and 35.8 maf

(4). Streamflow has been as low as 12.7 maf during

dry years. Normal storage in the basin is 23.5 maf,

or 74 percent of the mean annual streamflow. Total

withdrawals in the region are 19 maf annually, of

which 8.1, or 43 percent, are from ground water.

Sixty-eight percent of the total withdrawals were

for irrigation, of the total withdrawals, 12.6 m a f

were consumed, of which irrigation consumed

10.5, or 83 percent,

Streamflow volumes decrease from east to west

across the region, while considerable irrigated agriculture is practiced in both the northern and western portions of the basin. This creates an imbalance

between supply and use curves, which is illustrated

graphically in figure B-8 for the two central subregions, the Brazes (1203) and Colorado (1204). It can

be seen that in both these subregions, use exceeds

surface supply during all or much of the months

of June, July, August, and September. This excess

demand has been met in the past by overdrafting

portions of the Ogallala and Edwards-Trinity aquifers, which underlie the extreme western boundary

of the region. At least in the case of the Ogallala

aquifer, local depletions are occurring and can be

expected to grow as declining water tables and rising energy costs further restrict the use of this water source.

Water Resources Region 12: Texas-Gulf Region

In the central portion of the Texas-Gulf region, the use of water exceeds the supply during all summer months. An east-west gradient of water availability exists such that the supply-use relationship becomes progressively poorer from the Sabine-Neches subregion

in the east to the Nueces subregion in the southwestern portion of the State of Texas,

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Offstream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1201 ., . . . . . . 10,300 3,065 163 — 39 4 9 2,926 502 5 %

1202 . . . . . . . 7,500 1,913 617 297 335 9,641 1,601 18

1203 . . . . . . . . 1,810 1,262 1,215 1,157 473 4,758 3,061 84

1204 ., . . . . . . 4,720 1,032 4,395 3,767 694 6,255 4,850 82

1205 . . . . . . . . 3,940 387 832 318 154 2,508 1,245 26

Total region . . 28,270 7,660 7,222 5,578 1,705 26,088 11,259

Key mgd = million gallons per day (multiply by 1,120 to obtain acre. ft/year). bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App. B—Western Regional Water Characteristics . 367 — —. — —
368 . Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

— — —- — —- —

The Rio Grande Basin: Water Resources Region 13

The Rio Grande originates on the eastern slopes

of the Continental Divide in Colorado and flows

south through New Mexico to enter Texas at El

Paso. Along the Texas reach of the river, it forms

the international boundary between the United

States and Mexico. The total drainage area is

230,000 mi2

, of which 93,000 mi2 are in Mexico and

137,000 mi2 are in the United States. Forty-eight

thousand square miles drain into closed basins. The

principal tributaries of the Rio Grande and the

Pecos River, draining portions of New Mexico and

Texas, are the Rio Conchos in Mexico, the Rio

Puerco in New Mexico, and the Rio Chama in New

Mexico.

The streamflow in the Rio Grande basin is largely derived from melting snow in the mountains in

the northern portion of the region. Because of historical patterns of water diversion for irrigated agriculture, which predate European settlement of the

region and the initiation of systematic streamflow

measurements, and because of contributions from

the Mexican portion of the basin to total streamflow

at the mouth of the river, water supply estimates

based on total streamflow measurements are, in all

probability, misleading. The mean annual flow of

the Rio Grande originating within the United States

portion of the basin is estimated to be 1.4 maf (5)

or 5.6 maf (4). This fourfold difference in estimates

of annual flow volumes make management decisions regarding the Rio Grande basin particularly

difficult. The aggregate surface storage in the basin

is estimated to be 7.8 maf.

Total withdrawals are estimated to be 7.1 maf, of

which 6.4 maf, or 90 percent, are for irrigated agriculture. Total consumption is estimated to be 4.8

maf, of which 92 percent is used by irrigation.

Ground water withdrawals are 2.6 maf/year, which

is 37 percent of the total withdrawal.

While there is apparently a serious question concerning the accuracy of the supply data for the Rio

Grande basin, some idea of the nature of the extent

to which the water resources are being used can

be obtained from an examination of figure B-9. This

graphic comparison of supply and use relationships

is for the upper Rio Grande and Pecos Rivers,

where the ambiguities of the lower reaches are minimized to some extent. It can be seen that in both

subregions (1303 and 1304) use slightly exceeds

supply during most months of the year. The statement of the Second National Water Assessment that

“there are no surplus flows to meet new demands

or to expand existing uses” appears to be correct.

Because it is also estimated that ground water withdrawals represent an overdrafting of the basin aquifers by as much as 700,000 acre-ft/yr, it would seem

that a gradual reduction from current use levels is

inevitable.

Water Resources Region 13: Rio Grande River

In this entire region, water use exceeds or equals supply during virtually all months of the year. Water supply in the lower Rio

Grande is difficult to assess, owing to the ungaged contribution from Mexico. The available data suggest that there is little or no excess water in the lower reaches of the Rio Grande River.

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) imgd) streamflow (mgd)

1301 . . . . . . . . 267 114 590 0 18 932 581 690/o

1302 . . . . . . . . 343 1,071 611 265 129 2,118 1,247 96

1303 . . . . . . . . 582 108 679 290 73 873 630 102

1304 . . . . . . . . 122 58 400 89 74 897 562 94

1305 . . . . . . . . 1,230 1,183 55 13 436 1,501 1,220 88

Total region . . 1,230 2,534 2,335 657 730 6,321 4,24 0

Key mgd = million gallons per day (multiply by 1,120 to obtain acre-ft/year) bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App. B—Western Regional Water Characteristics ● 369

—.— — ——

●

❉

s or
370 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

The Colorado River Basin: Water Resources Regions 14 and 15

It has become customary in most discussions of

regional water resources to divide the Colorado

River Basin into an upper region (14) and a lower

region (15) at Lee’s Ferry, Ariz. This division is

designed to reflect provisions of the Colorado River

Compact but has limited hydrologic utility.

The Colorado River Basin has a total surface area

of approximately 257,000 mi 2

, of which slightly

more than 100,000 mi2 are in the upper basin. This

basin lies immediately west of the Continental

Divide and includes parts of Wyoming, Utah, Colorado, Arizona, New Mexico, and Nevada.

Estimates of mean annual streamflow for the entire Colorado River Basin vary from a low of 12.4

maf (5) to a high of 18.1 maf (4), Historically, the

flow of the river has varied widely, and the value

given for a mean annual discharge depends very

much on the period of time represented by the data

on which it is based, While this is equally true of

virtually all rivers in the Western United States,

which have a high variability from year to year, it

is perhaps most interesting in terms of the Colorado

River. Because the mean flow of the river has declined since the original division of the annual

streamflow among the upper and lower basin

States, it has become a well-known example of the

need to understand fully, prior to any allocations,

the regime of any hydrologic regime subject to political agreement (fig, B-10).

Figure B-10.—The Colorado River Basin Water Resources Region

The annual flow of the Colorado River at Lee’s Ferry, Ariz., immediately downstream from Lake Powell (above) and at

its outflow into the Gulf of California (below). The trend toward lower annual flow volumes in recent decades is largely confined to the lower Colorado, where a majority of the water diversions are located.

Annual flow of Colorado River

n Lee’s Ferry, Ariz,

1930 1940 1950 1960 1970 1980

Year

25

0

SOURCE: J Bredehoeft, “Physical Limitations on Water Resources in the Arid West, ” paper presented at Impacts of Limited Water for

Agriculture in the Arid West, Asilomar, Calif., 1982.

Water Resources Region 14: Upper Colorado River

Water supply and use for the Upper Colorado Water Resources Region. For this entire region, current water supply exceeds demand during every month of the year.

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1401 . . . . . . . . 3,680 1,677 64 0 115 3,186 1,019 22 ”/0

1402 . . . . . . . . 4,740 948 24 0 27 2,532 987 17

1403 . . . . . . . . 10,000 702 38 0 569 1,151 434 20

Total region . . 10,000 3,328 126 0 711 6,869 2,440

Key: mgd = million gallons per day (multiply by 1,120 to obtain acre-ft/year) bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App. B—Western Regional Water Characteristics 371

—...— ———
372 ● Water-Related—

Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands —

Both water supply and use characteristics of the

region vary widely between the upper and lower

basins and is largely the result of a much lower

population in the upper basin (344,000 v. 2,400,000

in the lower basin (1975 data)).

Normal reservoir storage in the basin is 71.5 maf,

of which 61.3 maf (86 percent) are located in the

lower basin, This represents 5.8 times the mean annual flow of the Colorado River, as estimated by

the Second National Assessment, Ground water

withdrawals from subsurface storage are estimated

at 5.7 maf/year, More than 95 percent of these

withdrawals occur in the lower basin and are estimated to consist of at least 50 percent of overdrafted water that is not being recharged.

Total withdrawals for the basin as a whole are

14.1 maf annually, of which slightly more than half

are made in the lower basin. Consumption is somewhat less equally divided. In the upper basin, 2.7

maf are consumed annually, while in the lower basin, 5.2 maf, or almost twice as much, are consumed. Withdrawals for irrigation are 94 percent

and 89 percent for the upper and lower basins, respectively, while consumption by irrigation is

higher in the lower basin, 45 percent to 32 percent

of total withdrawals.

Supply and use relationships for individual subregions within the upper and lower basins are

shown graphically in figures B-11 and B-12. The

Second National Assessment states that “The Colorado River system is one of the most controlled,

overburdened, and most oversubscribed river

systems in the Nation. ”

For individual subregions within the basin, there

is an excess of water supply over water use in all

subregions of the upper basin, while demand exceeds supply, often significantly, in the subregions

of the lower basin. The water deficit is being made

up by ground water overdrafting, which must continue if water-use patterns are not to change dramatically in the lower basin Whether this overdrafting can be continued into the indefinite future is

a matter of some speculation, given the spatially

variable nature of the ground water resource and

the fact that the water table is now declining at a

rate of 4 to 10 ft/yr in certain critical areas of the

region. With the completion of the Central Arizona

Project, the Second National Assessment reports

that “essentially all renewable surface and ground

water supplies will , , , be utilized” and water supplies will become inadequate to meet the needs of

the basin sometime before the year 2000.

Water Resources Region 15: Lower Colorado River

The relationship between supply and use In the Lower Colorado River basin. In two of the three subregions, the use of water

exceeds the supply in all but one month of the year. In the Gila River subregion, which includes the clties of Phoenix and Tucson,

Ariz., the imbalance between supply and use IS particularly extreme,

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1501 . . . . . . . . 2 7 2 5 0 7 0 5 31 2 2 0 7 3 21 “/0

1502 . . . . . . . . 1,55 0 18,86 3 960 290 1,02 0 2,42 4 1,05 9 1 1 4

1503 . . . . 2 0 1,04 9 3,97 8 2,12 0 151 6,27 3 3,46 3 2 5 4

Total region . . 1,55 0 19,96 2 5,00 8 2,41 5 1,20 2 8,91 7 4,59 5

Key mgd - million gallons per day (multiply by 1,120 to obtain acre. ft/year) bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App. B—Western Regional Water Characteristics . 373

— . —

z
374 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

—- — —. —————

The Great Basin: Water Resources Region 16

The Great Basin is a closed interior basin, lying

between the Rocky Mountains and the Sierra

Nevada Mountains of California, from which there

is no drainage. All precipitation falling in the basin

and all runoff entering it from the surrounding

mountains must ultimately leave by evapotranspiration or, possibly, ground water runout. The Great

Basin encompasses the western half of the State of

Utah and virtually all of Nevada and it has a surface area of 137,000 m i

2

. Mean annual runoff has

been variously estimated at between 2.9 maf (5) and

8.4 maf (4]. Average annual precipitation in this

basin is probably less than 10 inches/yr, while potential evapotranspiration values are estimated to

be several times this value. This suggests that

relatively little water is available for soil or ground

water recharge. The high range in the estimates of

runoff into this basin results, at least in part, from

a lack of actual measurements of the water produced from these many mountain sources and from

a certain amount of ambiguity concerning the ratio

of rain and snowfall to runoff.

Normal surface storage in the basin is 3,8 maf.

Surface area storage 130,000 acres, from which

355,000 acre-ft are estimated to be lost annually to

evapotranspiration. This amount represen s a specific alue of 2.7 ft of water annually-and is approximately 12 percent of the low estimate of total annual runoff into the basin.

Available ground water resources are estimated

to be approximately 525 maf, of which 1.6 maf are

withdrawn annually for an estimated overdraft of

662,000 acre-ft over recharge.

Total annual withdrawals within the Great Basin

are 9 maf, of which 4.2 maf are consumed. Irrigated

agriculture accounts for 7.8 maf of the withdrawals

(87 percent) and 3,6 maf of the consumptive losses

(86 percent). The existing estimated ground water

overdraft represents approximately 7 percent of

total withdrawals.

It can be seen from an inspection of figure B-13

that subregions on both the east (1601) and west

(1604) sides of the Great Basin have very similar

water supply/use characteristics. In both cases,

supply exceeds demand during winter, wherea s

during July to September or October, supply and

demand curves are almost identical. In subregion

1602, the Sevier River basin in southeastern Utah ,

demand exceeds supply during almost every month

of the year.

Water Resources Region 16: Great Basin

The relationship between water supply and use for the Great Basin region of Utah and Nevada This arid area depends on the

mountains to the east and west for its water supply. With the exception of the Sewer Lake subregion (1602) in southwestern Utah,

where use exceeds the supply during most months of the year, there is an annual excess of water over demand Water supply and

use are equal during the summer months over the entire region.

—

Ground water

—

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1601 : . . : 1,640 ‘-

680 581 43 98 3,557 ‘1 ,255 44 %

1602 ... . . . . 114 178 321 240 59 1,153 599 127

1603 . . . . . . . 132 144 433 286 93 1,770 ,077 117

1604 ., . . . . . . 676 236 89 22 77 1,511 848 56

Total region . . 2,56 2 1,239 1,424 591 327 7)991 3,77 9

Key mgd million gallons per day (multiply by 1,120 to obtain acre. ft/year) bg = billion gallons (multlply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App, B—Western Regional Water Characteristics ● 375

—————— —- —.— —-—

1.-,

,

I

.1<

m o

~ol x p6uJ
376 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

— —.

The Pacific Northwest Basins: Water Resources Region 17

The Columbia River Basin, which drains sections

of Montana, Idaho, Washington, Oregon, Nevada,

and the Canadian Province of British Columbia, has

a surface area of approximately 275,000 mi2 (160

million acres) and discharges an estimated 235 to

286 maf into the Pacific Ocean each year, This represents approximately 50 percent of all the surface

water available annually in the 17 Western States

and is roughly 20 percent of all the surface discharge from the entire continental United States.

Of the approximately 140 maf discharged by the Columbia River each year, nearly 50 percent enters

the United States from the province of British Columbia. The remainder is largely produced by melting snowpacks in the mountains of western Montana, the Idaho “panhandle,” and the east slopes

of the Cascade Mountains in Washington State.

Discussions of water supply and demand in the

Pacific Northwest region are complicated by the extreme variability that characterizes this region and

competing uses for water, Average annual runoff

depth ranges from less than 1 inch in portions of

the interior of Washington State to more than 100

inches at the higher elevations of the Cascade

Range along the western coast,

The region is divided into two hydrologic provinces by the Cascade Range. On the west slope of

this range, water is plentiful and fairly uniformly

distributed. East of the range, water is plentiful, but

concentrated in channels of the Columbia River

and its major tributaries, the Snake and Clark Fork

Rivers, thus draining the west slopes of the Rocky

Mountains in Idaho and Montana.

While the question of instream flow maintenance

is not unique to this river basin, it is particularly

well defined here because of the economic value

of the various competing instream and offstream

uses. If all competing uses are considered, the water

resources of the Pacific Northwest east of the Cascade Range in the Columbia River basin, are fully

used.

The normal reservoir storage in the region is 54.8

maf, which is slightly less than 20 percent of the

mean annual discharge. Over 1.7 billion acre-ft are

required annually for the generation of hydroelectric power in the basin. This means that all water

passing through the reservoir system must be used

approximately seven times for existing hydroelectric generation. While this water is theoretically

available at all times for other uses, in practice, conflicts arise. Ground water withdrawals (8.2 maf/yr)

are the third highest of all the water resources

regions in the Western United States. Ground water

overdrafting exists locally and could create local

shortages in the future.

Total withdrawals (42 maf annually) and offstream consumption (13 maf annually, of which irrigation consumes almost 12.5 maf) are among the

highest in the Western United States.

Figure B-14 illustrates the supply-use aspects of

the basin for two selected subregions. In the Upper Snake River, use of water is within 15 percent

of supply during July and August. Maximum offstream uses for the main Columbia River (subregion

1702) never exceed 30 percent of monthly streamflow. Only if instream flow requirements for the

salmon fishing industry, navigation, and hydroelectric generation are factored into the supply-use

question can an accurate picture of water use in

the Columbia River basin be obtained. If it is assumed that the demand for electricity remains essentially constant throughout the year, the Columbia River is heavily overcommitted.

Water Resources Region 17: Pacific Northwest

Relationship between supply and use in the Pacific Northwest region. While this region is often considered to be a water surplus

area, it is apparent that along the Upper Snake River, water use is approaching supply during the summer months of each year. Along

the Columbia River, the various uses to which the water is put (e.g., hydroelectric generation, fishery support, irrigation) mean that

little excess water is actually available once all these demands are satisfied,

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1701 . . 31,400 3,579 242 10 406 1,924 626 2%0

1702 . . . . . . . . 115,000 6,107 742 332 664 7,774 4,023 8

1703 . . . . . . . . 10,600 4,082 5,591 225 830 20,640 5,128 33

1704 ... , . . . . 29.700 1,061 102 30 89 1,422 439 16

1705 . . . . . . . . 212,000 1,796 440 16 0 2,404 756 5

1706 . . . . . . . . 42,200 1,139 178 0 0 1,098 194 1

1707 . . . . . . . . 1,070 76 53 14 25 2,364 747 41

Total region . . 255,270 17,839 7,348 627 2,014 37,626 11,913

Key mgd = million gallons per day (multiply by 1,120 to obtain acre. ft/year) bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
App. B—Western Regional Water Characteristics ● 377

. .— —

Figure B-14. —The Pacific Northwest Water Resources Region

I

I

150.000

100

0

1702

Hydroelectric energy \

Upper/Middle

Columbia

I 1 I I I I I I I I

25-160 0 - 25 : QL 3
378 “ Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

The California Basins: Water Resources Region 18

The California region includes the State of California and Klamath County, Ore. It has a total surface area of approximately 160,000 mi2 and a mean

annual surface runoff variously estimated at between 53 maf/yr (5) and 69 maf/yr (4). According

to WRC, approximately 85 percent (45 maf/yr) is

discharged from two subregions in the northern

portion of the State, the Klamath and Sacramento

Rivers. At the same time, more than half of the approximately 21 million inhabitants of the State live

in subregion 1806, which includes the metropolitan

areas of Los Angeles and San Diego. This subregion

has an annual discharge of 6.5 maf annually, slightly more than 10 percent of the total runoff of the

State (5). The fact that significant amounts of irrigated agriculture also exist in the southern half

of California, principally in the San Joaquin Valley,

only serves to compound the severe water supplyuse imbalance in the State.

Normal reservoir storage for California as a

whole is approximately 39 maf, which is equivalent

to less than 75 percent of the smaller of the two

estimates of total streamflow. The California water

resources region ranks first among those in the

Western United States in terms of total water withdrawals (44.4 maf), total ground water withdrawals

(21.5 maf), total water consumed (29.8 maf), and

total water consumed by irrigation (27.2 maf).

A comparison of supply-use curves for northern

and southern subregions within the State illustrates

the imbalance (fig, B-15). In the Sacramento River

basin (1802), in spite of extensive irrigated agriculture, water supplies exceed uses during all months

of the year. In two southern basins, the San Joaquin

River and the Los Angeles-San Diego basins, water

demand slightly exceeds surface supplies during

almost every month of the year. There appears to

be no water available for future development in the

southern portion of the State without some change

in water supply or use patterns.

Water Resources Region 18: California

The relationship between water supply and use for selected subregions in the California region. This is a graphic illustration of

the water imbalance between the northern and southern portions in California. In a northern subregion (the Sacramento), supply exceeds use during all months of the year, while in the central San Joaquin-Tulare and southern California subregions, virtually all available

water is used during every month of the year.

Ground water

Mean Normal withdrawals Evaporation Withdrawals Total Off stream use

streamflow surface Total Overdraft from reservoirs, (mgd) (fresh consumption to total

Subregion (mgd) storage (bg) (mgd) (mgd) stockponds (mgd) and saline) (mgd) streamflow (mgd)

1801 . . . . . . . . 26,000 1,298 181 0 0 2,256 737 3 %

1802 . . . . . . . . 13,900 5,446 4,052 233 138 7,756 5,398 28

1803 . . . . . . . . 2,830 3,717 10,659 1,250 315 17,828 12,649 89

1804 . . . . . . . . 2,570 790 616 0 13 7,744 809 24

1805 . . . . . . . . 1,490 412 1,181 83 20 3,999 833 37

1806 . . . . . . . . 446 850 2,020 491 137 14,168 5,887 101

1807 . . . . . . . . 139 183 451 140 46 454 328 100

Total region . . 47,375 12,697 19,160 2,197 669 54,205 26,641

Key” mgd = million gallons per day (multiply by 1,120 to obtain acre-ft/year) bg = billion gallons (multiply by 3,070 to obtain million acre-ft)

SOURCE Second National Water Assessment, 1978
. .

App. B—Western Regional Water Characteristics . 379

———— —-— . ———

I

I

I
. —

380 . Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

Ground-Water Resources Regions

The availability, ease of extraction, and total

quantity of ground water present at a site is determined largely by the local geology, climate, and surface hydrologic regime. While climate and the surface hydrologic regime commonly vary together at

a site, the geology, which determines the extent to

which rocks will hold and transmit ground water,

often varies independently of the surface environment. For this reason, ground-water resources

regions do not necessarily correspond to surfacewater resources regions. In assigning an area to a

given ground-water resources region, arbitrary decisions must often be made concerning the relative

importance of climate and geology. For the purposes of this assessment, the delineation of these

regions used is that originally developed by Thomas

and subsequently adopted by others (1), The general

location these regions in shown in figure B-16. They

are:

1.

2.

3.

4.

5.

6.

7.

Western Mountain Ranges,

Alluvial Basins,

Columbia Lava Plateau,

Colorado Plateaus and Wyoming Basin,

High Plains,

Unglaciated Central Region, and

Glaciated Central Region.

Western Mountain Ranges

The Western mountain ranges, consisting primarily of the Rocky Mountains and the Cascade and

Sierra Mountain ranges near the Pacific Coast,

serve as the principal source of water in the

Western United States because the bulk of the

regional precipitation falls here and resulting

runoff supplies streams and aquifers. Rocks in the

region are generally hard and dense, They shed

water rather than absorbing it and ground water

is limited although some ground water may be extracted from alluvial materials, sands, and gravels,

filling the floors of small intermontane valleys.

Most local water supplies are obtained from

springs, wells in valleys, and surface reservoirs, Not

enough wells have been drilled in the higher mountains to establish any trends in ground water availability, although the character of the rocks there indicate that such water may be obtained from fractured areas. Because of the limited human use of

the Western mountains ranges, no widespread

water-quality problems have been mentioned in the

literature,

Alluvial Basins

Alluvial basins are found in a southwestern tier

of States reaching from California to central New

Mexico. They reach as far north as northern

Nevada and include portions of western Utah and

southern Arizona. The basins in this region consist of erosional materials removed from the adjacent mountains and deposited as alluvium in the

basin floors, This alluvial material is composed of

interbedded sands, gravels, and clays and is recharged principally by streams flowing across it

that originate in the surrounding highlands, The

alluvial fill functions as an ideal aquifer and creates

an opportunity for development of high-yielding

wells,

Ground water development for irrigated agriculture has been extensive in this region because of

the prevailing arid climate. The rate of recharge of

these aquifers is generally much less than the rate

at which water is extracted from this source, and

ground water levels are declining as the amount of

water in storage is depleted. The local significance

of this problem varies, depending on the amount

of ground water use and the source and volume of

the recharge water. Locally, artificial recharge has

helped alleviate the problem of ground water depletion.

Ground water is a very important source of water

in this region, where surface runoff is generally

nonexistent over a large percentage of the area, For

example, in Arizona, 61 percent of the total water

use is derived from ground water. Given the extent

to which this resource is being consumed and contaminated in the areas of highest use, there is

legitimate cause for concern regarding the future

potable water availability in some portions of the

aquifers underlying the major population centers

of this region (see ch. IV for a discussion of general

water-quality problems affecting or likely to affect

the West).

Locally, in such areas as Phoenix and Tucson,

Ariz., the alluvial aquifers are intensively used. It

is estimated that in Maricopa County, which includes the City of Phoenix, ground water use was

30 times the rate of natural recharge. For Pinal

County, ground water depletion was estimated to

be 12 times the rate of recharge. In the Tucson

valley, the rate of overdraft is three to one.

For California, the largest user of ground water

in this region, ground water supplies about 48 percent (21.5 maf) of the total annual freshwater withdrawals in the region, representing an estimated
App. B—Western Regional Water Characteristics 381

Figure B-16. —The Major Ground Water Regions of the Western United States

SOURCE D Todd, Ground Water Hydrology, 2d ed (New York John Wiley & Sons. Inc , 1980)

25-160 0 - 27 : QL 3
382 Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

overdraft of 2,197 million gallons per day (2.5

maf/yr), or 11.5 percent of estimated average annual recharge.

A number of ground-water quality problems have

been identified in this ground-water resource region by Federal and State agencies, including the

intrusion of seawater into aquifers as the result of

overdrafting of ground water, water-quality degradation from percolation of irrigation waters, and

localized pollution of ground water from industrial

and municipal sources.

The availability of large quantities of ground

water has been a significant factor in the economic

growth of the Southwestern United States. The continued availability of this resource for existing uses,

given the extent to which it is being “mined” and

the potential for serious pollution from both agricultural, municipal, and industrial sources, is questionable.

Columbia Lava Plateau

This ground-water resource region is located

principally in eastern Washington and southern

Idaho, Geologically, it was formed largely by surface volcanic rocks, mainly lava flows, interbedded

with or overlain by alluvium and lake sediments.

Water originates chiefly from the mountains to the

east and west of the Plateau, the Cascade and Rocky

Mountain ranges. The lava flows tend to be highly

permeable, as a result of cracks which formed at

the time the lava cooled, and thus form highly productive aquifers. Large volumes of excess ground

water discharge as major springs are the source of

surface rivers that drain into the Snake and Columbia Rivers. Ground water is most readily available

in the valley bottoms because of the great thickness

of the lava flows. In the higher plateau areas, however, deep wells may be required to extract ground

water for irrigation.

No widespread water-quality problems have been

reported for this region. The Water Resources

Council estimates that approximately 8.2 maf of

water are withdrawn annually from the ground

water storage in this region, representing an estimated 8.5 percent overdraft, or 70,000 acre-ft in excess of natural annual recharge. This overdraft may

be localized, however; USGS states that “[o]n the

Snake River Plain in Idaho, . . . excess irrigation

water has filtered into the ground and joined the

original ground water body, increasing the rate of

recharge of ground water into the Snake River by

nearly 50 percent. In this area as a whole, . . . water

has not been mined, it has been put in the bank” (l).

Colorado Plateaus and Wyoming Basin

The Colorado Pleateus and Wyoming Basin region is located in southwestern Wyoming and in

the Four Corners region of portions of Utah, Arizona, Colorado, and New Mexico. The aquifers in

this region consist of consolidated rocks that are

generally horizontal but have been folded, tilted, or

fractured in places. This region is arid to semiarid,

generally at an altitude high above sea level, and

deeply dissected by the rivers and streams flowing

through it. Prospects for large-scale ground water

development are poor. Small water supplies for domestic and livestock purposes are generally available, however, Most aquifiers are sandstone beds,

although limestone and alluvium also yield water

in a few places. No estimates exist of ground water

consumption specifically for this resource region,

It is assumed to be low, since there is limited water

to be withdrawn from ground water storage,

Ground water quality problems identified by the

Second National Assessment for this region include

high levels of dissolved solids and contamination

by toxic industrial wastes in portions of Colorado

and New Mexico.

The High Plains (Ogallala Aquifer]

Probably the best known aquifer in the Western

United States is the High Plains, or Ogallala,

aquifer. This ground-water resource region includes most of Nebraska and Kansas and portions

of eastern Colorado, New Mexico, and the Texas

and Oklahoma panhandle. The problems of the

Texas, Kansas, and Oklahoma sections of the aquifer have come to typify, for the press and public,

some of the problems represented by ground water

overdrafts.

In portions of Colorado, Nebraska, Texas, Oklahoma and Kansas, alluvium forms a vast plain extending eastward from the Rocky Mountains, The

bulk of it is classified as a single stratigraphic unit,

the Ogallala Formation, which covers older rocks

to thicknesses exceeding 450 ft. The sand and

gravel of the formation constitute an aquifer that

may yield as much as 1,000 gallons per minute, locally, The region is generally semiarid so that

ground water recharge from precipitation is extremely small. The productiveness of wells has encouraged pumping of ground water, however, especially for irrigation in Texas. This water has been

derived primarily from storage. As a result, water

tables have declined substantially since extensive

pumping began in the 1950’s.
App. B—Western Regional Water Characteristics ● 383

. . . — — . — ————

The Ogallala aquifer has been used to support irrigated agriculture in the high plains of Texas since

the development of suitable high-speed engines and

turbine centrifugal pumps in the mid-1930’s, Significant use of the ground water resources of the

southern portion of the aquifer did not begin until

the 1950’s, however, spurred by the development

of center-pivot sprinkler systems and the availability of low-cost natural gas. Even though the problem of overdrafting the Ogallala aquifer was recognized almost from the outset of extensive agricultural use, pumping from the aquifer increased

from 1.9 maf in 1950 to 11.1 maf in 1975 in the

Texas portion of the aquifer alone.

Some elements of the ground water problem in

the High Plains region are generally instructive for

other portions of the Western United States where

the future of ground water resources is in doubt,

Ground water mining has widely differing effects,

even with in an area that is relatively homogeneous

with respect to geology, climate, and agricultural

use. Throughout the High Plains region, the ground

water source is referred to as a single aquifer.

However, the properties and characteristics of that

aquifer vary greatly from Nebraska to the Texas

panhandle, and ground water is unevenly distributed within and among the individual States. Depending on the configuration of the aquifer and its

physical composition, individual areas will be affected very differently by ground water mining.

The dewatering of the Ogallala aquifer has had

the most serious consequences in the Texas, Oklahoma, Kansas, and Colorado portions, where the

aquifer is thinner, the saturated thickness is less,

and the permeability is generally lower, Even there,

however, the natural variability of the aquifer has

produced water level declines ranging from 20 to

more than 120 ft, so that there is no single impact

on irrigated agriculture. In the northern portion of

the aquifer, primarily Nebraska, the saturated thickness is up to 10 times that of the southern portion,

and nearly 60 percent of all the water contained in

the aquifer is found there (3). Even in this relatively water-rich portion of the aquifer, “ . . . the

ground water pinch is prompting officials to consider allocating available ground water by metering it in control areas of the Natural Resources District” (2). In spite of the overall volume of water in

the northern portion of the aquifer, there have been

water-level declines in some areas necessitating

deeper wells and higher pumping lifts with increased pumping costs. The continued use of the

large volumes of water required by irrigated agriculture in the northern portion of the Ogallala

aquifer will become increasingly affected by institutional and economic factors, such as the legal status

of ground water and energy costs.

Unglaciated Central Region

This is a large and complex ground-water

resource region, extending from southern New

Mexico to the southeastern portion of Montana,

from east of the Rocky Mountains to east of the

High Plains region in central Texas, Oklahoma, and

the southeastern corner of Kansas. It is an area of

plains and plateaus underlain by consolidated

rocks. Alluvial deposits of substantial width and

thickness form good aquifers along the Arkansas,

Platte, and Missouri Rivers but are not generally

important elsewhere. Aquifers in most of the region

are composed of limestone or sandstone with low

to moderate yields. Some of the most unproductive

aquifers in the Western United States are found in

this region because of low water yields, high salinity, or a combination of both. On the other hand,

wells drilled into cavernous limestone may yield

large amounts of high-quality water. This extreme

local variability makes generalizations concerning

ground water availability or quality in this region

unreliable. Local testing is required to establish the

values for both. Except locally, ground water does

not represent a major source of water in the region.

No problems with ground water availability for

this region were discussed in the Second National

Water Assessment. Water-quality problems, generally involving high levels of salinity, are identified

for portions of central Texas and Oklahoma.

Glaciated Central Region

This region is quite similar to the Unglaciated

Central region except for the mantle of unconsolidated deposits of the ice and meltwaters of the continental glaciers that covered it at one time. It includes the northern portion of Montana, much of

North Dakota and eastern South Dakota, and a

small portion of northeastern Kansas. The glacial

materials consist mostly of fine-grained rock debris

intermixed with beds of sands and gravels. In portions of the area, the glacier material is nearly 1,000

ft thick and forms an important aquifer. In this region, 1arge-diameter wells yield sufficient water to

meet domestic needs.
384 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

Hazardous Waste Sites by State

Arizona:

Scottsdale . . . . . . . .

Kingman . . . . .

Goodyear . . . . . . .

Globe . . . . . . . . . . . . . .

Tucson . . . . . . .

Phoenix ., . . . . .

California:

Rancho Cordova . . .

Hoopa . . . . . . . . . . . . .

Ukiah . . . . . . . . . . . . . .

Redding . . . . . . . . . .

Sacramento . . . . . . . .

Richmond . . . . . . . .

Fullerton . . . . . . .

Cloverdale . . . . . . . . . .

Fresno . . . . . . . . . . . .

Fresno . . . . . . . . . .

Glen Avon Heights . .

Colorado:

Leadville . . . . . . . .

Idaho Springs . . . . . .

Denver . . . . . . . . . .

Boulder ., . . . . . . . . .

Commerce City . . . . .

Commerce City . . . . . .

Idaho:

Rathdrum . . . . . . . . . .

Smelterville . . . . . . . . .

Caldwell . . . . . . . . . .

Kansas:

Arkansas City . . . . . . .

Holiday . . . . . . . . . . . .

Wichita . . . . . . . . .

Cherokee County . . .

Montana:

Anaconda . . . . . . . . . .

Libby . . . . . . . . . . . . . .

Milltown ., . . . . . . . . .

Silver Box/

Dear Lodge . . . . . .

North Dakota:

Southeastern . . . . . . . .

Nebraska:

Beatrice . .

New Mexico:

Clovis . . . . . . . . . . . . . .

Milan . . . . . . . . . . .

Albuquerque . . . . . . .

Churchrock . . . . . . .

Oklahoma:

Criner. . . . . . . . . . .

Ottawa County . . . . .

Indian Bend Wash Area

Kingman Airport Industrial Area

Litchfield Airport Area

Mt. View Mobile Home* **

Tucson International Airport*

19th Avenue Landfill*

Aerojet*

Celtor Chemical

Coast Wood Preserving

Iron Mountain Mine*

Jibboom Junkyard

Liquid Gold

McColl

MGM Brakes

Purity Oil Sales, Inc.

Selma Pressure Treating

Stringfello* *

California Gulch

Central City, Clear Creek*

Denver Radium Site*

Marshall Landfill* * *

Sand Creek

Woodbury Chemical*

Arrcom (Drexler Enterprises)

Bunker Hill

Flynn Lumber Co.

Arkansas City Dump* * *

Doepke Disposal, Holiday

John’s Sludge Pond

Tar Creek, Cherokee Co.

Anaconda—Anaconda

Libby Ground Water

Milltown

Silver Bow Creek

Arsenic Trioxide Site* **

Phillips Chemical

ATSF/Clovis*

Homestake*

South Valley* **

United Nuclear Corp. *

Criner/Hardage*

Tar Creed*

Oregon:

Portland . . . . . . . . . .

Albany . . . . . . . . .

South Dakota:

Whitewood ., . . . . . . .

Texas:

Grand Prairie . . . . . .

Houston . . . . . . . . .

Crosby . . . . . . . . . . . .

Houston . . . . . . . . . . .

Highlands . . ., . . . . .

La Marque. , . . . . . .

Crosby . . . . . . . . .

Orange County . . . . .

Utah:

Salt Lake City . . . . . .

Washington:

Spokane . . . . . . . . . .

Tacoma ... . . . . . . .

Tacoma ... . . . . . . . .

Wyoming:

Laramie ... . . . . . .

Gould, Inc.

Teledyne Wah Chang

Whitewood Creek* * *

Bio-Ecology*

Crystal Chemical*

French, Ltd. *

Harris (Farley St.)*

Highlands Acid Pit*

Motco ” * *

Sikes Disposal Pits*

Triangle Chemical

Rose Park Sludge Pit* * *

Colbert landfill

Commencement Bay,

Near Shore Tide Flat*

Commencement Bay,

S. Tacoma Channel*

Baxter/Union Pacific

● ✝ IPL/EEI ● ● = States’ Designated Top Priority Site

“IPL” means the Interim Priorities List of 115 sites announced m October 1981. “EEL”

refers to the Expanded Eligibility List, an addttional 45 sites designated in July 1982

as eligible for remedial actions

SOURCE U S Environmental Protection Agency, Hazardous Waste Sites by State,

Proposed Superfund Priorities List, December 1982

Appendix B References

1.

2.

3.

4.

5.

Baldin, H., and McGuinness, C., A Primer on Ground

Water (Reston, Va.: U.S. Geological Survey, 1963).

Lehr, Jay H., “Data Base on Ground Water Quality and

Availability: Effects on Productivity of U.S. Croplands

and Rangelands, ” Impacts of Technology on U.S.

Cropland and Rangeland Productivity, vol. 11, Part C,

Background Papers, December 1982.

Luckey, R., Gutentag, E,, and Weeks, J., Water-Level

and Saturated-Thickness Changes, Predevelopment to

1980, in the High Plains Aquifer in Parts of Colorado,

Kansas, Nebraska, New ,Wexico, Oklahoma, South

Dakota, Texas, and Wyoming, U.S. Geological Survey

Hydrologic Atlas HA-652, 1981.

Murray, C., and Reeves, E., Estimated Use of Water

in the United States in 1975, U.S. Geological Survey

Circular 765, 1977.

U.S. Water Resources Council, The Nation Water

Resources 1975-2000, Second National Water Assessment (Washington, D. C.: U.S. Government Printing

Office, 1978).
Appendix

Institutions

Note: The information in this appendix further elaborates on material presented in chapter V.

State Initiatives in

Water-Resources Planning

Early State involvement with water rights in the

Western States related to allocating water rights to

individuals as property rights, As discussed in

chapter V, the “distributive” character of early

water resources projects required local consent. A

number of economic benefits accrued to States;

there were also some less obvious disadvantages.

The impetus for development of specific waterresource projects usually came from the Federal

agencies which had expertise and planning capacity and was triggered by demand or crises.

In the early days of reclamation projects, States

generally deferred to Federal agency initiatives in

large-scale water-resources development, These

agencies, staffed largely by engineers, were expert

in large dam and related construction projects.

Decisions on project development were essentially political and rarely involved difficult technical

benefit-cost evaluations (e.g., esthetics, noneconomic impacts), realistic repayment plans, or consideration of potential alternatives, such as changing

patterns of settlement or behavior, to meet development goals. In 1964, the Executive Secretary of

the Upper Colorado River Basin, speaking generally

about the States, observed:

Many States have poor organizations for longrange planning and their water resource agencies

lack financial support. Some States even appear to

lack the proper agencies that can do their share of

the overall planning job. In many instances, initiatives in planning rests with Federal agencies. State

and local governments are often in a position to approve or disapprove plans without having made adequate studies for major decisions needed in the field

of water resources. (U.S. Senate, 1964, in ref. 18)

In the 1960’s and 1970’s a number of events combined to begin a gradual shift to more active State

roles. local perceptions began to change about environmental values associated with water, and

these views were voiced by local groups to local

politicians. Environmental impact statements and

water-quality standards brought more expertise to

the State level as State agencies became more aware

and involved with local impacts of development.

Federal funding for capital-intensive water projects

showed signs of diminishing, Federal funds and

planning assistance became available through such

mechanisms as the Water Resources Planning Act

of 1965 and the Office of Water Research and

Technology (OWRT) within the Department of the

Interior to help States build their own water research capabilities.

The result has been a growing and increasingly

visible level of State interest, awareness, and involvement in water-resources planning and management. For example, in November 1982 the National Conference of State Legislatures (NCSL) issued a detailed and well-documented report, Water

Resources Management: Issues and Policy Options,

to assist State legislatures formulate water-related

policies and programs (17). Though State efforts

have varied, three kinds of activities help illustrate

this shift:

1. protecting instream uses,

2. dealing with conflicting uses of water, and

3. water-resource planning and regulation.

Water for Instream Uses

Multiple use of a State’s water resources is advocated by most States. Within the last 10 to 15

years, this concept has taken on a new dimension

in the form of minimum stream flows to protect and

preserve instream values for fish, wildlife, and

recreational purposes. While it is true that some of

these programs are modest in nature, they reflect

a shift in traditional State policy. It is somewhat

ironic that efforts to preserve instream flows come

at a time when most States are experiencing even

greater demands for additional diversions from the

streams for other uses. This has and will make the

task of protecting instream values much more difficult. Nevertheless, considerable amount of activit y is occurring with respect to nonconsumptive

uses such as minimum streamflow protection with

potential important implications for sustaining and

advancing agricultural uses of water at the State

level.

The type, scope, and strength of the various State

programs in this field vary greatly, For example,

California has adopted, among other strategies, a

State version of a wild and scenic rivers act. Colorado, Idaho, and Montana have enacted legislation that allows administrative agencies to protect

385
386 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

certain instream values by reserving water for this

purpose. Oregon, one of the first States to recognize

instream values, created a Water Policy Review

Board in 1955 with powers to set minimum perennial streamflows sufficient to support aquatic life

and minimize pollution. Utah allows the State Engineer to consider the natural stream environment

when evaluating new applications to appropriate

water. Other States have charted different courses.

In application, protecting instream flows involves

tradeoffs with existing water uses. As such, decisionmaking to protect such flows has been difficult

and complicated even where authority exists. For

example, while the Oregon Water Board has had

the authority to classify and allocate water for instream flow purposes, instream rights are a lower

class than the water rights granted prior to the 1955

enactment and thus are junior to most of the water

rights in the State. Taking administrative action to

protect instream flows would involve changing actual or allocated offstream uses. Consequently, according to one policy expert, minimum instream

flow protection in Oregon has not been guaranteed

under the 1955 legislative authorization (19).

Resolving Problems of Conflicting Uses

States are becoming increasingly involved in resolving conflicting uses of water. Water scarcity

plus rising water demands have brought forth a variety of attempts at the State level to reallocate or

transfer private water rights, A few State experiences illustrate some of the approaches being taken:

1. Arizona, where a comprehensive legislative

framework is being used to allocate and reallocate water rights;

2. a subbasin in New Mexico, where a local water

district is expanding its traditional functions;

and

3. Colorado where economic, market-oriented

procedures are used to resolve water conflicts,

Arizona relies on ground water supplies and

since the 1930’s has been “mining” this resource,

In the 1970’s, as use conflicts grew and competitors

turned increasingly to the courts to protect their

interests, legislation was passed mandating the

development of a Groundwater Management Study

Commission composed of legislators and representatives from mining, municipal, and agricultural interests to rewrite the ground water code. Pressure

also came from the Secretary of the Interior, who

indicated that his recommendations on the Central

Arizona Project water allocations would be positively influenced by strong ground-water law

reforms.

The Arizona Groundwater Management Act was

passed on June 12, 1980, ” creating the first comprehensive legislative framework for management

of ground water resources in Arizona. It established

active management areas (AMAs) in parts of the

State, where, owing to the magnitude of ground water pumping, active ground water management was

necessary to ensure long-term supplies. Management plans detailing water duties and approved

water-use practices are required for each AMA,

The act allowed all legal ground water pumping

that had existed at the time the act was passed to

continue, It called for validation of such grandfathered rights, the issuance of permits under certain criteria for new rights, and restriction on new

irrigated acreage. Because the goal of the act is to

eventually balance ground water withdrawals with

the safe yield of aquifers, new uses will depend on

the willingness of existing uses (in other words, irrigated agriculture) to sell their water rights. This

will have significant ramifications on land use in

Arizona and the future of agriculture in the State

(3).

The middle Rio Grande basin of New Mexico has

been the setting for growing conflict between the

historical, rural character of the State and the

modern demand for transfer of water rights to industrial and municipal uses. Originally, this basin

was almost exclusively devoted to agriculture. Now

it has become the largest urban center in the State.

Thus, the principal agricultural institution in the

area—the Middle Rio Grande Conservancy District—has come under increasing pressure to accommodate these new uses (3),

Because of competing uses, a market for water

rights has developed in the basin. Since water rights

were originally attached to agriculture, any reduction or diminution of these rights threatens the traditional role of the basin’s Conservancy District,

The district became involved with litigation as it

tried to protect agricultural water rights and prevent transfers from within the district’s boundaries

to a new owner and use outside the boundaries. It

has considered the prospect of leasing its water to

other uses of higher economic value in the urban

area. The district might become more involved with

use of its existing agricultural rights to offer recreational and related amenities to the urban population through more active management of its lands

and water as “greenbelt” areas in the urban vicinity, Whether such a shift to multiple-use management is possible depends on the speed with which

the district can assume a new role as regional water

*Ariz. Ret Stat Ann sees, 45-401 to 636 [Supp, 1981-62).
App. C—institutions . 387

————. — . — . — —

Photo credit: Ted Spiegel, 1982

A suburb in Tucson, Ariz., an area of extensive ground

water overdraft, with a major interest in domestic,

urban, and industrial water use, where agriculture

may become a lower priority.

manager to provide the new kinds of services

required,

Colorado has had some of the most extensive experience with water transfers as a means of dealing with conflicting uses. Colorado water law

allows the free transfer of private water rights as

long as third- party rights are protected. This provision has resulted in the development of largely

economic, market-oriented procedures. Over the

last 20 years large transfers of water from the agricultural sector to municipal and industrial uses

have been made. Purchases of agricultural rights

have been particularly active for the Colorado communities along the eastern side of’ the Rocky Mountains (the “Front Range”). Shifts are even more evident in the use of water from the Bureau of Reclamation Colorado-Big Thompson (CBT) project, In

1957, 15 percent of the project water was owned

by municipalities; by 1978, municipalities owned

34 percent (3).

At the same time, Colorado is a Western State that

recognizes environmental interests. In 1973

changes were made in the State’s constitution and

water laws recognizing instream use of water as a

beneficial use and allowing the State to appropriate

or purchase water rights for such use. The large

shifts in water use plus these emerging social values

resulted in the commissioning in 1976 of a Colorado Water Study to analyze “future water allocations . . . in terms of their impacts upon values of

fundamental concern to broad segments of society” (4).

A major purpose of the Colorado Water Study

was to look at the State’s water-allocation practices

in the context of water scarcity and the growing

pressures of economic growth, energy development, and increased population. Of particular concern was the loss of the economic base which irrigated agriculture represented and the “rural lifestyle” associated with the agricultural way of life.

The concern focused on whether unrestricted water transfers for solely economic values are also adequately serving other important values such as the

rural lifestyle and environmental preservation (4).

Many new demands for water are being placed

on Colorado’s water supply. AS transfers continue

to be proposed, some may be found detrimental to

the present instream flow values when they involve

a change in use or change in point of diversion. The

instream flow classification as a beneficial use may

provide a mechanism whereby noneconomic considerations could be incorporated into a basically

market-oriented water-allocation process.

Water-Resource Planning and Regulation

State water-resource management programs have

never been more in need as traditional water uses

grow and compete with rapidly accelerating demands for water for energy development and instream flows. Opportunities to stretch available

water resources in the foreseeable future are going

to come primarily from better water resources management programs at the local level.

The development of a State water plan is an important step in minimizing friction between competing interests for available water while advancing overall public interest. Some Western States

have begun to develop water-planning mechanisms,

The preparation of water plans can be expensive

and requires a good deal of time and the input of
388 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

— —-

many people representing different disciplines and

interests. For any plan to be effective, competing

interests must perceive a full and fair opportunity

to advance their views. Moreover, the resulting

management decision must reflect a balanced approach that adequately takes into account differing

views and local interests. According to some Western law experts, a planning process should proceed

under State guidelines that are mandated by law

and become part of the state regulatory program (7).

Utah is one of the States actively debating the

development of a comprehensive approach to water-resources planning and management. Since

1975 it has been considering possibilities for a

statewide water plan (6). The proposed plan is a

combined system of planning and regulation

through integrated management of water within

hydrologic units. The elements of the 1975 proposed plan noted here are illustrative of the kinds

of considerations likely to be faced by many Western States as they attempt to manage their limited

water resources among competing uses.

In the 1975 proposal, the Utah statewide water

plan would emerge through the preparation of separate unit plans for hydrologic units in the State.

The unit plans would involve a substantial amount

of local participation and would be under State

supervision, with general guidelines and criteria

applicable on a statewide basis. Once completed

and approved at the State level, the various unit

plans would have a regulatory status and would

guide water management in their respective areas

until modified. The plan would cover all uses, including agriculture.

The Utah proposed plan has several key elements

for managing water resources. It incorporates water-quality considerations into the development of

the plan, using the expertise of water-quality officials. The hydrologic unit plans, once adopted

would serve as a regulatory as well as a planning

tool. In addition, any prospective appropriator

(whether an irrigator, municipality, or industry)

could examine the unit plan for the particular hydrologic unit of interest and immediately determine

whether there were any unappropriated water or

rights available for purchase or transfer.

The Utah Legislature did not adopt the plan in

1975 because of concern by many—principally

those owning irrigation water rights—that there

might be some impairment or adverse impact on

their water rights if they were brought within the

hydrologic unit plans and a statewide plan, According to the drafters of the plan, however, any vested

water rights would be entitled to the protection of

constitutional due process and would not be impaired or taken without payment of just compensation (7). The position of those who advocate the

plan has been that an integrated hydrologic/regulatory approach may be one of the best prospects

for protecting, sustaining, and perhaps expanding

the use of water for irrigated agriculture in the arid

and semiarid States (7).

Studies of the Economic

Values of Western Water*

The Economic Value of

Water for Irrigation

The direct value of water in irrigation is measured in terms of the increment of profit to the producer with irrigation as compared to profits

without irrigation. Several methods may be employed to make this calculation. One is an “ex ante”

(before the fact) approach, which computes the

change in net income from assumptions about crop

prices, yields, production technology, and production costs, An alternative technique maybe labeled

“ex post” (after the fact), which relies on statistical

analysis of actual production data. The ex ante

method is often most convenient for planning in

specific cases, and is generally used by the Bureau

of Reclamation and other Government agencies

that deal with water. Various statistical approaches

serve to validate the analytic measures, and are regarded by many analysts as more reliable owing to

their base in “real, observable data. ” Any analytic

measures—ex ante or ex post—can be abused by improper assumptions about prices, yields, and/or input requirements, or some cost items that may be

ignored, Experience has shown, however, that

when properly performed, the methods yield similar results.

What is the value of irrigation water? The value

of the marginal unit of water may reflect water scarcity as well as the cost of supplying the marginal

unit. Local production conditions such as rainfall,

temperature, length of growing season, and market

situations will also have an impact, so considerable

variation in water value across the West can be expected, Highly productive areas such as the Imperial Valley or the San Joaquin Valley in California

will have high values for water. Marginal production areas such as the high meadows of Wyoming

will show low values.

———

* Excerpted from: R, Young, “Allw,iting the Water Resource: Market

Systems and the Economic Value of M’ater, ” O’1’A commissioned paper,

1982,
App. C—institutions ● 3 8 9

. — — -. .—— .—— .

Beattie and Frank (2) used 1974 census data as

the basis for a statistical analysis of agricultural output. One of their purposes was to learn how agricultural output is influenced by resource inputs, including land, labor, machinery, chemicals, and irrigation water. The results yielded water values (expressed in current 1982 dollars) of $10 to $15/acre-ft

in the intermountain valleys of the Upper Colorado and Snake River basins; $20 to $25/acre-ft in the

desert Southwest and central California; and $40

to $45/acre-ft in the Ogallala ground water region

of the High Plains.

Hewitt, et al. (12), reported similar results using

a much different technique. Their interregional

supply-demand model for California yielded prices

at the margin of $23 to $35/acre-ft in the Central

Valley and southern California and $7 in the Imperial Valley, Gollehon, et al. (10), show estimated

prices for irrigation water in 11 Rocky Mountain

subregions. This study is somewhat atypical since

it studies the value of water that might be lost to

the region or transferred to other uses. When the

water supply is reduced by 20 percent, two regions

showed water valued in excess of $20/acre-ft, four

were between $10 and $20/acre-ft, and six were

below $10/acre-ft.

The Department of Commerce recently sponsored a study of water value in the Ogallala region

of the High Plains, The study showed a value of $60

to $80/acre-ft for water used in irrigation. These

values move upwards wit h the passage of time, reflecting (assumed) increases in crop prices and

yields through the year 2000.

The estimates of the value of water used to produce certain specialty crops (e. g., flowers, spices,

berries) may be somewhat higher than the figures

cited above. However, such uses will account for

less than 10 percent of total irrigation water use in

the foreseeable future. These crops are not, and

probably will not be, of much significance for the

formation of national water policy. This being the

case, a rough estimate suggests that 90 percent o f

all irrigation demand is probably for water that

costs no more than $40/acre-ft.

The Value of Water in Industry

Energy production is the major consumer of water used for industrial purposes in the arid West.

Most of this water is used for cooling thermalelectric powerplants. Several processes can be used

for cooling, depending on water scarcity and price.

Young and Gray (23) use an alternative cost approach to show that it is economical to convert existing plants from a pass-through cooling system to

an evaporative cooling tower when water costs rise

above $5/acre-ft (1982 price levels). Methods designed to conserve cooling water are much more

expensive. Gold, et al. (9), in a study for the U.S.

Environmental Protection Agency, report that the

break-even points for combination wet-dry cooling

systems run around $600/acre-ft, while the shift to

a completely dry, water-free cooling system would

be economical only if water were extremely expensive—perhaps as much as $1,400/acre-ft. Abbey’s

(1) comprehensive analysis of water and energy

problems in the Colorado River Basin provides similar estimates. Hence, the large-scale stem plants

proposed for several areas in the West could, if

necessary, be willing to pay an amount many times

the value of water in neighboring and competing

agricultural uses.

Recent experience suggests, however, that even

the large ‘water requirements of huge powerplants

can be met with relatively little loss of water to agriculture in the surrounding area. Much of the 45,000

acre-ft required by the Intermountain Power Project (IPP) in Utah will be met by using conveyance

losses or water used on saline soils that have little

or no present agricultural value.

Leigh (14) has studied the value of water for coal

slurry pipelines. His values are based on cost savings that accrue from not having to rely on rail

transportation to move the coal (the alternative cost

method of measurement). The value of water in a

Colorado-to-Texas pipeline system is estimated to

exceed $1,600/acre-ft. This estimate of value is,

however, extremely sensitive to changes in the level

of railroad freight rates. Reductions in freight rates

could reduce the imputed value of water, although

it is not likely to drive the value below willingness

to pay for irrigation water. That is, agriculture cannot expect to compete with this use of water.

The need for water in recovery of hydrocarbons

from oil shale has received considerable attention.

Valuing water in this use could be accomplished

using the alternative cost method or by estimating

the change in net income accruing to oil-producing

firms. The alternative cost approach suggests that

water could substitute for considerable capital and

labor in the refining process and hence be very valuable, The change in net income approach requires

that the production process be profitable before

positive residual income can be imputed to water.

Under current and anticipated petroleum prices,

shale oil extraction is not economically feasible,

therefore, water has a zero or negative value in this

use.
390 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

Value of Water in Households

While willingness to pay for water delivered to

households is readily observed and has been studied by many analysts, deriving a marginal value of

water to households that is comparable and commensurate with estimates of raw water values in

streams is, however, quite difficult. Household water that is treated (filtered and chlorinated), stored,

and delivered to the user on demand is a much different economic commodity than the raw and untreated river water that is used in irrigation or industry. Hence, a deduction for treatment, storage,

and delivery costs must be made to make the prices

and values comparable. An estimate may be derived using a method suggested by Young and Gray

(23) and based on data developed by Howe and

Lineaweaver (12), This approach finds that lawn

sprinkling is valued at about $150/acre-ft and inhouse uses at $250/acre-ft (in 1982 dollars), A

weighted average of water in the two uses would

be about $220/acre-ft. In another study Hewitt, et

al. (13), do not distinguish between industrial and

household demand, Their municipal and household

sector estimates for 1980 (in 1982 prices) are about

$160 to $200/acre-ft.

An alternative estimate can be derived from market values of water in the Colorado-Big Thompson

project (in northeastern Colorado) that can be

transferred to urban uses. Gardner and Miller (8)

report that the price of water rights—i.e., the price

of exclusive rights to water—averaged $2,450/acreft in 1981. Converting this figure to an annual acrefoot value requires assumptions regarding the capitalization rate and expectations about future inflation. However, if the interest rate is about 8 to 9

percent (which seems plausible), and the planning

horizon is long, the value of water is nearly equivalent to the $240 determined by Young and Gray

(23) and Hewitt, et al, (13).

Hydroelectric Power Generation

Because evaluation of hydroelectric projects has

usually proceeded on the assumption that falling

water is a free good, recorded efforts to value water

in this use are rare. In recent years competition for

water—even falling water—has intensified, so evaluation methods have had to be developed. The procedure that has emerged centers on the cost of generating electricity using some alternative method

of generation (alternative cost method). When this

method is used, the value of water is derived by

deducting capital and operating costs of the generation and transmission system from the revenue

earned by selling the power. The residual, if any,

is attributed to the water resource (change in net

income method). Specific value estimates vary, depending on the differences in head (the distance the

water falls before turning the turbines), distances

to load centers, costs of the steam-generating alternative, and the construction costs of the dam and

storage facilities behind it. Even given these variables, values are also expressed for one site only or

for several sites on a given reach of a river. Young

and Gray (23) report single-site values ranging from

$3.30 to $10/acre-ft in 1982 prices in the Western

States. The higher values are associated with sites

that have relatively high heads and can, thus turn

larger turbines. Most of these sites are found on the

Colorado River. Whittlesey and Gibbs (22) report

values for power generation in the Columbia Basin

of over $30/acre-ft (1982 prices) for water that goes

through all of the dams below Franklin Roosevelt

Reservoir, including Grand Coulee, This figure is

higher than that reported by Young and Gray because of continued reuse at several generating stations and because of the higher costs associated

with alternative energy sources in or near the Columbia River Basin, While single-site values for hydropower are not large relative to the values found

in diversionary uses, diversions that are made high

in a basin can lead to loss of large cumulative benefits stemming from reuse as the water passes

through a number of facilities.

Valuing Water in Water Load Dilution

Water released for dilution of pollutants has value

to the extent it reduces damage that the pollutants

may impose on subsequent users. Precise estimates

are difficult to derive since the detrimental effects

depend on the particular pollutant, distance downstream, water temperature, rate of flow, and the

quality of the waste-receiving water used for dilution. Most analysts have estimated values by assuming that the value of a unit of “clean” water is

equivalent to the cost of treating effluent so that it

does not reduce the quality of the water.

The results of these studies generally imply that

dilution values are generally quite low. Merritt and

Mar (16) showed dilution water in the Willamette

Basin (Oregon) to have a value of about $l,30/acreft (1982 price levels). Gray and Young (11) applied

the aforementioned technique to several regions in

the West. Their estimates of value in dilution

ranged from $0.08/acre-ft (Colorado Basin) to

$3.25/acre-ft in the lower Missouri. Employing data

from the Colorado River Board of California, Young
-. . . —

App. C—Institutions ● 3 9 1

— —

and Gray (23), however, derived a value of water

for dilution or reduction of salinity in the Colorado

Basin at about $15/acre-ft.

The Value of Water in

Water-Based Recreation

Water-based recreational services, by tradition

and policy, are not often priced by market processes. Indeed, recreation and recreation services

are so varied and so abstract that many people scoff

at the notion that any reasonable value can be attributed to the resources used to produce them. The

normal problems of valuing water are compounded

since the value of water for recreation must be

derived from a prior, synthetic, and sometimes arbitrary imputation of the value of the recreational

services themselves. The problem is further complicated because the recreational uses of water are

often complementary to other water uses rather

than competitive with them. Water stored for irrigation, hydropower production, or flood control can

be enjoyed by swimmers or fishing enthusiasts

without diminishing its usefulness in its other uses.

In such cases, it is difficult to value the water and

only slightly less difficult to ascertain the value of

the recreational experience.

However, the growing demand for recreation is

creating situations in which recreational uses are

beginning to compete with other classes of instream

or off stream use. At this time, few analysts are

working on measuring water values that are suitable for comparing allocations among alternative

uses that include recreation.

Daubert, Young, and Gray (5) formulated a direct

interview procedure to elicit hypothetical bids from

recreationists on the value of water in flowing

streams. Applied to a sample of visitors to the

Poudre Canyon in northeastern Colorado, this approach yielded estimates of economic value related

to river flow used for fishing, whitewater kayaking,

and noncontact streamside recreation such as picnicking, The resulting marginal bid values for typical summer streamflow were converted to dollars

per acre-foot and were $9/acre-ft for fishing,

$5/acre-ft for whitewater sports, and $7/acre-ft for

the noncontact recreational experiences. Walsh, et

al. (z I), performed similar analysis on western Colorado streams, reporting $13/acre-ft for fishing,

$4/acre-ft for kayaking, and $2/acre-ft for rafting

when flows were maintained at 3.5 percent of maximum.

These findings lend support to the notion that

nonconsumptive uses, even though they are nonmarketed, have economic value to users. While

many are skeptical of the validity of benefit

estimates based on responses to questions regarding hypothetical situations, a preferable alternative

technique to generate quantitative estimates of instream flow values has not been developed, While

recognizing that estimates using this technique are

subject to more than the usual error, they appear

to be reasonable reflections of user preferences.

Since these estimates are for values in a public, nonexclusive use, they must be used with great care,

especially when incorporated into water-management policy decisions.

Fish and WildIife Habitat

Efforts to value habitat directly in economic

terms are relatively recent. Many suffer from one

or more of the potential difficulties noted earlier,

particularly in valuing total product rather than incremental units of water. *

The problem remains of relating physical water

requirements to habitat productivity, an issue that

appears not to have been addressed in literature

that is readily accessible. The estimates made by

Lynn, et al. (15), indicate a marshland value of less

than $1/acre. Water supplies per acre for the habitat

of one crab species would not be highly valued in

strict economic terms.

Navigation

provisions of facilities for inland waterways

navigation has always been an important part of

Federal water policy. Estimates of the value of

water for this purpose are almost nonexistent, since

the usual approach to benefit-cost analysis of navigation projects implicitly assumes water to be a free

good (as with hydropower). A sample approach (23)

credited water with the savings from transporting

commodities by water rather than by rail, pipeline,

or truck. They reported positive values for water

used for navigation only on the Mississippi, Ohio,

and Tennessee River systems. Elsewhere, such as

on the Missouri and the Columbia Rivers, the total

cost of building and maintaining a navigation system exceeded the savings: no benefit was creditable

to navigation,
392 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands ——

Appendix C References

I. Abbey, David, “Energy Production and Water Resources in the Colorado River Basin, ” Natural l?esources /ourna] 19(2):275-314, 1979.

2.

3.

4.

5,

6.

7.

8.

9.

10,

11.

Beattie, ~. R., Department of Agricultural Economics

and Economics, Montana State University, Bozeman,

Mont., personal communication to R. Young in ref.

23, 1980 .

Brown, L., McDonald, B., Tysseling, J., and DuMars,

C., “Water Reallocation Market Proficiency and Conflicting Social Values, ” Water and Agriculture in the

Western U. S.: Conservation, Reallocation and Markets, G. Weatherford (cd.), Studies in Water Policy and

Management, No. 2 (Boulder, Colo.: Westview Press,

1982), pp. 191-256.

Colorado Department of Natural Resources, Office

of the Executive Director, The Colorado Water Study:

Directions for the Future, October 1978, in ref. 3

Daubert, J. T., and Young, R. A., with Gray, S. L.,

“Economic Benefits From Instream Flow in a Colorado Mountain Stream,” Completion Report 91 (Fort

Collins, Colo.: Water Research Center, Colorado State

University, June 1979).

Dewsnup R. and Jensen, D., “Proposed Procedures

for Planning, Allocating and Regulating Use of Water

Resources in Utah, ” unpublished report, Utah Division of Water Resources, 1975, in ref. 7.

Dewsnup, R., Jensen, D., and Quealy, M., “Selected

Legal Constraints and Opportunities, ” OTA commissioned paper, 1982.

Gardner, Richard, and Miller, T. R., “An Explanation

of Price Behavior in the Water Rights of Northeastern

Colorado,” Department of Economics, Colorado State

University, Fort Collins, Colo., proceedings of a paper

prepared for delivery to the Annual Conference, of

the American Agricultural Economics Association,

Logan, Utah, August 1982.

Gold, G., et al., “Water Requirements for SteamElectric Power Generation and Synthetic Plants in the

Western United States,” Environmental Protection

Agency Report No. 600/7-77-037, February 1977.

Gollehon, N. R., Lansford, R. R., et al., “Impacts on

Irrigated Agriculture from Energy Development in

The Rocky Mountain Region, ” Southwestern Review

of Management and Economics 1:61-88, spring 1981.

Gray, S. L., and Young, R. A., “The Economic Value

of Water for Waste Dilution: Regional Forecasts to

1980, ” Journal of the Water Pollution Control Federation 46(4):1653-1662, July 1974.

———

12. Howe, C. W., and Lineaweaver, F. P., “The Impact

of Price on Residential Water Demand, ” Water Resources Research 3(2), 1967.

13, Hewitt, R. E., Mann, D. E., and Vaux, H. J., Jr., “The

Economics of Water Allocation, ” Competition for California Water: Alternative Resolutions, Ernest A.

Englebert (cd.) (Berkeley, Calif.: University of California Press, 1982), pp. 136-162.

14. Leigh, Marie, “Competition for Water: Energy v. Agri15.

16

17

18.

19.

20.

21.

22.

23.

24

culture, ” paper prepared for ASCE Conference,

Water and Energy: Techmca] and Policy Issues, ” Fort

Collins, Colo., June 1982.

Lynn, G. D., et al., “Economic Valuation of Marsh

Areas for Marine Production Processes, ” Journal of

Environmentid Economics and Management 8(2):175-

186, June 1981.

Merritt, L. B., and Mar, B. W., “Marginal Value of

Dilution Waters, ” Water Resources Research 5(6),

December 1969.

Morandi, L. B,, and Lazarus, G. H., Water Resources

Management: Issues and Policy Options, National

Conference of State Legislatures, Denver Colo., full

report and summary, 1982.

Schooler, D., and Ingram, H., “Water Resource Development,” Policy Studies Review, vol. 1, November

1981, pp. 243-254.

Skurdahl, L., “Problems in Oregon Water Management, Oregon Foresight Occasional Paper Series No.

6“ (Portland, Ore.: Institute for Policy Studies, Portland State University, 1980).

State of Arizona, Arizona Ground Water Management Plan (draft) (Tucson: Arizona Department of

Water Resources, 1982).

Walsh, R. G., et al., “An Empirical Application of a

Model for Estimating the Recreation Value of 1nstream Flow, ” Completion Report 101 (Fort Collins,

Colo.: Water Resources Research Institute, Colorado

State University, October 1980).

Whittlesey, Norman, and Gibbs, Richard, “Energy

and Irrigation in Washington, ” Western Journal of

Agricultural Economics 3(1:1-11), 1978.

Young, R. A., and Gray, S. L., “The Economic Value

of Water: Concepts and Empirical Estimates, ” Technical Report, U. S. National Water Commission

(Springfield, Va.: National Technical Information

Service, PB 21-356, 1972].

Young, R., “Allocating the Water Resource: Market

Systems and the Economic Value of Water, ” OTA

commissioned paper, 1982.
Appendix

Method of the Study

Most OTA studies rely on outside experts to

guide the study, suggest topics for special emphasis,

provide specially tailored research summaries, and

review staff work. Separate but sometimes overlapping groups filled each of these roles in this assessment (table D-l). An advisory panel provided overall guidance throughout the course of the assessment. A number of planning workshops and working group meetings were held to address more

specific topics and several reviewers examined the

draft assessment. Other OTA studies have used

similar groups but the number of people involved

in this assessment was larger than average.

This assessment also was unusual in its strong

regional focus. Staff from OTA made extensive site

visits throughout the West, many meetings were

held in the region, and outside experts were almost

exclusively drawn from Western States.

Phase 1: Planning

Preliminary meetings were held while OTA staff

visited private sector, academic and government

experts in 12 of the 17 Western States. Three planning workshops, in Denver, Salt Lake City, and

Berkeley, provided additional background information and identified important issues. Many of the

colleagues who took part in these initial sessions

participated throughout the 2-year assessment.

The advisory panel had its first meeting 2 months

after the assessment began. Its 19 members included farmers, ranchers, scientists, government

officials and representatives from private industry

and public interest groups. Dr. James Kendrick, Jr.,

Vice President for Agriculture and University Services, University of California-Berkeley, chaired the

panel. Members discussed the general format and

scope of the study and advised that OTA form several working groups to analyze issues in more

detail,

Four working groups (one each on rangeland, irrigation, dryland agriculture, and social sciences)

were formed and met 1 month later. Each group

identified several topics for contractors’ reports,

completed detailed outlines of each topic, and suggested several potential authors.

Phase 2: Commissioning and

Evaluating Contractors’ Reports

Working group and advisory panel members

helped to recruit contractors and, in some cases,

also served as authors. Fifteen major papers were

Table D-1 .—Assessment Meetings

Members

Group Date Location attending

Advisory Panel:

Meeting 1 . . . . . . . . . . . . . . . . . . . . . . . Oct. 22-23, 1981

Meeting 2 . . . . . . . . . . . . . . . . . . . . . . . May 26-27, 1982

Meeting 3 . . . . . . . . . . . . . . . . . . . . . . . Oct. 28-29, 1982

Meeting 4 . . . . . . . . . . . . . . . . . . . . . . . Mar. 29-30, 1983

Planning Workshops:

Drylands . . . . . . . . . . . . . . . . . . . . . . . . Sept. 11, 1981

Rangelands . . . . . . . . . . . . . . . . . . . . . Sept. 18, 1981

Irrigation . . . . . . . . . . . . . . . . . . . . . . . . Sept. 25, 1981

Work groups:

Meeting 1:

Rangelands . . . . . . . . . . . . . . . . . . . Nov. 19-20, 1981

Drylands . . . . . . . . . . . . . . . . . . . . . . Nov. 12-13, 1981

Irrigation . . . . . . . . . . . . . . . . . . . . . Nov. 23-24, 1981

Social Science. . . . . . . . . . . . . . . . . Dec. 7-8, 1981

Meeting 2:

Rangelands . . . . . . . . . . . . . . . . . . Apr. 26, 1982

Drylands . . . . . . . . . . . . . . . . . . . . Apr. 27, 1982

Irrigation . . . . . . . . . . . . . . . . . . . . . Apr. 29, 1982

Social Science. . . . . . . . . . . . . . . Apr. 28, 1982

SOURCE Office of Technology Assessment

Washington, DC.

Washington, D.C,

Washington, D.C.

Washington, D.C.

Denver, Colo.

Salt Lake City, Utah

Berkeley, Calif.

Washington, D.C,

Washington, D.C.

Washington, D.C.

Denver, Colo.

Denver, Colo.

Denver, Colo.

Denver, Colo.

Denver. Colo,

18

18

18

18

11

10

11

7

7

8

11

7

7

8

11

393
394 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

—..—- — — — — . -.

commissioned and six smaller ones were contributed without contractual arrangements. The authors met with corresponding working group members during the second meeting. Draft papers were

reviewed and suggestions made for final versions.

The second meeting of the advisory panel evaluated

the results of the working group reviews and provided additional comments for the authors. Final

copies of the contractor’s reports were completed

at the midpoint of the assessment and served as important source materials.

Phase 3: Preparing the

OTA Assessment

The meetings of the authors, working groups, and

advisory panel provided OTA with clear indications of strengths and weaknesses of the assessment’s draft organization and background information. As a result, the assessment was reorganized

to follow the hydrologic cycle instead of agricultural land uses. In some cases, it was necessary to

research and synthesize additional information

from the scientific literature or to bring in specialists to fill significant gaps. Extensive staff work was

done during preparation of the first assessment

draft to complete these tasks.

The advisory panel reviewed the first draft of

OTA’s work during its third meeting, reaffirmed

the desirability of the hydrologic cycle format, and

suggested modifications. These changes were made

before the draft was sent to about 50 independent

reviewers from a wide range of organizations. The

external review process was finished by the time

of the fourth and final advisory panel meeting 2

months before the assessment was due for delivery

to the OTA Congressional Board, Discussions at the

final meeting focused on the major findings of the

assessment and policy options for Congress.

The results of this assessment are presented in

two documents. This volume contains the full assessment of domestic issues. A smaller background

paper, “Water Related Technologies for Sustainable

Agriculture in Arid/Semiarid Lands: Selected Foreign Experience, ” was also prepared. It presents

six case studies of innovative foreign practices that

may have important wider applications for sustainable agriculture in arid/semiarid lands.
Appendix E

Acronyms and Glossary

AGNET

BOD

CAM

CAP

CBO

CROHMS

DBCP

DOC

DOD

DOI

EDIS

EPA

FIARBC

FIFRA

FWPCA

GAO

HM

ISS

MCL

NAS

NASQAN

NAWDEX

NCAR

NCSL

NNRIS

NWS

OTA

OWRT

PIK

RCRA

R&D

SAR

SCS

SSARR

TNRIS

Acronyms

—Agricultural Computer Network

–biochemical oxygen demand

—crassulacean acid metabolism

—Central Arizona Project

—Congressional Budget Office

—Columbia River Operation

Hydromet Management System

–dibromochloropropane

—Department of Commerce

—Department of Defense

—Department of the Interior

—Environmental Data and Information Service

—Environmental Protection Agency

—Federal Inter-Agency River Basin

Committee

—Federal Insecticide, Fungicide,

and Rodenticide Act

—Federal Water Pollution Control

Act

—General Accounting Office

—Hydrometeorological Streamflow

Prediction

—irrigation scheduling services

—maximum contaminant level

—National Academy of Sciences

—National Stream Quality Accounting Network

—National Water Data Exchange

—National Center for Atmospheric

Research

—National Conference of State

Legislatures

—Nebraska Natural Resources Information System

—National Weather Service

—Office of Technology Assessment

—Office of Water Research and

Technology

—payment-in-kind

—Resource Conservation and

Recovery Act

—research and development

—Sodium Absorption Ratio

—Soil Conservation Service

—Streamflow Synthesis and Reservoir Regulation

—Texas Natural Resources Information System

USDA —U.S. Department of Agriculture

USGS —U.S. Geological Survey

WATSTORE—Water Data Storage and Retrieval

System

WHO —World Health Organization,

United Nations

WRC —Water Resources Council

WRSIC —Water Resources Scientific Information Center

WUE —water-use efficiency

Acre-foot: A measure of the volume (e.g., irrigation

water) that would cover 1 acre of land (43,560

square feet) to a depth of 1 ft. In the metric system, volume is expressed as cubic meters. One

acre-ft equals 1,233.6 cubic meters.

Agriculture: The human use of land for direct production of plants and animals and materials produced by them. For purposes of this assessment,

agriculture does not include the use of land primarily for the production of timber.

Agronomic water-use efficiency: The amount of

harvestable or economic biomass produced per

water lost by transpiration and evaporation.

Arid and semiarid lands: Those lands where cropwater requirements exceed the plant-available

water (growing season precipitation plus soil

water stored in the root zone) by a significant

amount. Arid and semiarid lands comprise about

one-third of the contiguous United States, principally the 17 Western States—the focus of this

study.

Biological water-use efficiency: The total dry

weight of plant material produced per total water

lost by transpiration,

Dryland agriculture or farming: Crop production

without irrigation in regions where available

water is the most limiting factor.

Efficiency: The amount of output per unit of input. Efficiency can be measured at many different scales and for many different factors. For example, “irrigation efficiency” may refer to several different measures of theoretical, technical,

economic, and actual water use, within irrigation

districts, on farms, or in fields.

Evaporation: The process by which a liquid is

changed into a gas. Evaporation that takes place

from the seas and oceans is the main source of

water on land areas.

395
396 l Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

—

Evapotranspiration: The loss of water from the soil

by evaporation and from plants by transpiration.

Externalities: Unintended consequences of an exchange or a production process.

Ground water: The part of the subsurface water

below the soil water zone in spaces, or interstices, of subsurface geological formations or of

rock or unconsolidated sediment completely saturated with water.

Ground water “mining”: Withdrawal of ground

water at a rate in excess of its natural or artificial

recharge.

Hydrologic cycle: The central concept i n

hydrology that relates the interdependence and

continuous movement of all forms of water

through the vapor, liquid, and solid phases. The

components of the hydrologic cycle are: precipitation, evaporation, transpiration, infiltration,

percolation, runoff.

Infiltration: The process whereby water soaks into, or is absorbed by the soil layers.

Irrigation agriculture or farming: Crop production

using the application of water to lands primarily to provide the water for plant growth that is

not provided by rainfall during the growing

season.

Long-term: Means more than one human lifespan

(approximately 70 years) from the date of this

report.

Onfarm irrigation efficiency: The ratio or percentage of the volume of water stored in the soil root

zone and used by the crop to the volume of water

delivered to the farm.

Percolation: The downward flow of water through

soil and permeable rock formation to the ground

water table.

Precipitation: Water added to the surface of the

Earth from the atmosphere. It may be either

liquid (e.g., rain and dew) or solid (e.g., snow,

frost, and hail).

Rangeland: Those areas on which the native

vegetation is predominantly grasses, grasslike

plants, forbs, and shrubs. These lands have generally been thought unsuitable for cultivation and

have traditionally been used for grazing domestic

livestock. More recently, rangelands have been

managed also for the production of wood and

other plant products, water, recreational purposes, and wildlife habitat.

Renewable natural resource base: Includes soil,

water, and all the physical, chemical, and biological components of agricultural resource systems.

Runoff: The portion of precipitation that comprises

the gravity movement of water in surface channels or depressions.

Soil water (or soil moisture): The part of the subsurface water immediately below the surface in

the spaces, or interstices, of the soil.

Subsidence: Collapse of underground, waterbearing formations caused by ground water

overdraft.

Subsurface water: All water that exists below the

surface of the Earth in interconnected openings

(“interstices”) of soil or rock, includes soil water

and ground water.

Total streamflow: Computed flow that includes effects of consumption, water transfers, and

evaporation from manmade reservoirs, but not

ground water overdraft.

Transpiration: The process by which water vapor

passes through a living plant and enters the

atmosphere.

Water: A mineral composed of two parts hydrogen

to one part oxygen with a unique combination

of properties: liquid at room temperature, requires large amounts of energy for conversion

from liquid to vapor and from solid to liquid, resistant to temperature changes, strong attraction

between its own and other molecules, dissolves

many substances, transmits visible light but absorbs thermal radiation.

Water, “new”: Additional water available at a site

in excess of that which would be available as a

result of unmodified natural processes. This

would include that made available, for example,

from interbasin or intrabasin transfers, weather

modification, or watershed management. This

concept has little meaning from a hydrologic

point of view. The total volume of water within

a definable region is fixed by the hydrologic

cycle. Water can be transferred only from one

phase or location to another, while the term

“new” water suggests that it is created. Additions

at one point will inevitably produce deficits at

another because of fundamental water-balance

constraints. There are no exceptions to this

although the lack of knowledge about some processes makes it appear that “new” supplies are

available.

Water pollution, nonpoint sources: Diffused

wastes reaching water through land runoff,

washout from the atmosphere or other means.

These pollutants are extremely difficult to

control.

Water pollution, point sources: Waste discharges

from identifiable points. These pollutants are

amenable to direct control.

Water “savings”: The amount of water that remains for additional use after technological

manipulation of the hydrologic cycle. Technolo-
—

App. E—Acronyms and Glossary . 397

——

gies include evapotranspiration suppression, reduced agricultural withdrawals, and decreased

infiltration and deep percolation. A water ‘ ‘savings” can only be defined in the context of the

water balance of a particular site and is largely

an economic, not a hydrologic, concept. Hydrologically, water cannot be “saved” or “lost.” It

can only be transferred from one place or phase

of the hydrologic cycle to another.

Water supply: The streamflow volume that would

occur at the outflow point of each subregion if

consumption were eliminated, ground water

overdrafting were discontinued, and current

water transfer and reservoir practices were continued.

Water table: The upper surface of the zone of

ground water,

Water use, Consumptive: Water withdrawal and

use in such a way that it is no longer available

for additional uses—e.g., due to evaporation,

transpiration, and ingestion by animals.

Water use, Nonconsumptive: Withdrawals and use

that return water to supplies for additional use—

e.g., irrigation “return flows, ” hydroelectric

energy generation, and instream-flow requirements.

Watershed: The fundamental geographic units of

hydrology, land area surrounded at its perimeter

by highlands that cause precipitation falling within the watershed’s bounds to flow or drain generally toward its center to form rivers or streams;

a watershed is also known as a river basin, and

could be as large as that of the Missouri River

Basin (at least 500,000 mi 2

) or as small as an

ephemeral tributary to that river (a few tens of

acres),

Conversion Table for

Common Measures

1

1

hectare equals: 100 meters X

square meters; 2.471 acres;

miles

acre equals: 0.405 hectares

100 meters or 10,000

or 0,00386 square

1 cubic meter equals: 35,31 cubic ft; or 264.2 U.S.

gal

1,000,000 cubic meters equaL: 810.6 acre-ft

1 acre-ft equals: 1,233.6 cubic meters; or 325,931 gal

25-160 0 - 2 8 : QL 3
Appendix F

Contractors, Work Groups,

and Workshops

OTA COMMISSIONED PAPERS-CONTRACTED AUTHORS

Rangeland

An Overview of Rangelands in U.S.

Arid/Semiarid Regions of the

United States

Thad Box

College of Natural Resources

Utah State University, Logan

Technologies for Capturing and

Detaining Water on Rangeland

John Buckhouse

Rangeland Resources Department

Oregon State University, Corvallis

Karl Wood

Department of Animal and Range Science

New Mexico State University, Las Cruces

TochnoIogies for Increasing Water

Use Efficiency On-Site

Ronald E. Sosebee

Department of Range and Wildlife Management

Texas Tech University, Lubbock

Larry Rittenhouse

Range Science Department

Colorado State University, Fort Collins

Paul T. Tueller

Knudtsen Renewable Resources Center

University of Nevada, Reno

Technologies for Improving Off-Site

Water Quantity, QuaIity, and Timing

Gerald F. Gifford

Range Science Department

Utah State University, Logan

Mountain Snowpack

Snowpack Management in the

Mountains of Arid and Semiarid Lands

Nelson Caine

Institute of Artic and Alpine Research

University of Colorado, Boulder

Dryland

Dryland Agriculture

Hayden Ferguson

Plant and Soil Science Department

Montana State University. Bozeman

Charles Fenster

University of Nebraska, Scottsbluff

William H. Lyle

Texas Agricultural Research and Extension

Center

Charles Wendt

Texas Agricultural Research and Extension

Center

Biological Water Use Efficiency

in Dryland Agriculture

Wayne Jordan

Blackland Research Center

Texas

Ronald Newton

Department of Plant Sciences

Texas A&M University, College Station

William Rains

Agronomy and Range Department

University of California, Davis

39a
.-

Irrigation

Overview-Irrigation in U.S.

Arid and Semiarid Lands

Marvin Jensen

Fort Collins, Colo.

Supply and Distribution

of Water for Irrigation

Charles Brockway

Snake River Research Center

Idaho

Efficient Use of Water on the Farm

Jim Gilley

Lincoln, Nebr.

Elias Fereres

Land, Air, and Water Resources Department

University of California, Davis

Social Sciences

The Sustainability of Rural

Non-Farm Economics in Water

Dependent Agricultural Areas

Paul Barkley*

Department of Agricultural Economics

Washington State University, Pullman

Allocating the Water Resource:

Market Systems and the Economic

Value of Water

Robert A. Young

Fort Collins, Colo.

Economic Efficiency of Agricultural

Water Use in the West

Ron Lacewell

Department of Agricultural Economics

Texas A&M University, College Station

Role of Economics in the Adoption of

Water Use Technology in Agriculture

Richard J. McConnen

Department of Agricultural Economics

Montana State University, Bozeman

————

“Also assisted in techni( al edit of m.onomics section of ch. i’

App. F—Contractors, Work Groups, and Workshops ● 399

Social impacts of Water Technology

on Western Populations

Timothy Finan

Department of Anthropology

University of Arizona, Tucson

Ted Downing

Department of Anthropology

University of Arizona, Tucson

John Bennett

Department of Anthropology

University of Arizona, Tucson

Environmental Concerns

Frank Gregg

School of Renewable Natural Resources

University of Arizona, Tucson

Public and Related

Environmental Concerns

Dwight Metzler

Kansas Department of Health

Roger Carlson

Kansas Department of Health

Selected Legal Constraints

and Opportunities

Dick Dewsnup*

Salt Lake City, Utah

Dallin Jensen

Attorney General’s Office

Salt Lake City, Utah

Michael Quealy

Attorney General’s Office

Salt Lake City, Utah

Changing Western Water Institutions

Dean Mann

Department of Political Science

University of California, Santa Barbara

Water Quality and Western Agriculture

Irina Cech

Health Sciences Center

University of Texas, Houston

* Deceased
400 . Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

— . — ———...———-————. ——

WORK GROUPS, 1981-82

Dryland Agriculture Work Group

Bruce Beattie

Department of Agricultural Economics

Montana State University, Bozeman

Ernest French

North Dakota State Agricultural Experiment

Station

Joe Goodin

Department of Biological Sciences

Texas Tech University, Lubbock

John Hanks

Soils and Biometeorology Department

Utah State University, Logan

Jim Heyser

Los Alamos National Lab

New Mexico

Bob Papendick

USDA Agricultural Research Service

Washington State University, Pullman

Robert A. Stewart

USDA Agricultural Research Service

Conservation and Production Research Lab

Texas

Irrigation Agriculture Work Group

Don Alford

Water Resources Consultant

Boulder, Colo.

Stanley Davis

Department of Hydrology and Water Resources

University of Arizona, Tucson

Paul Fischbach

Department of Agricultural Engineering

University of Nebraska, Lincoln

Anthony E. Hall

Department of Botany and Plant Sciences

University of California, Riverside

Marvin Jensen

USDA Agricultural Research Service

Colorado

Ron Lacewell

Department of Agricultural Economics

Texas A&M University, College Station

Joe Lord

J. M. Lord, Inc.

California

Peter Wierenga

Department of Agronomy

New Mexico State University, Las Cruces

Rangeland Agriculture Work Group

Farrell Branson

U.S. Geological Survey, WRD

Colorado

Bruce Godfrey

Department of Economics

Utah State University, Logan

Dan Laster

Roman L. Hruska

U.S. Meat Animal Research Center

Nebraska

Bill Laycock

Research Leader

Forage and Range Management Research

Crops Research Lab

Colorado State University, Fort Collins

Brian Sindelar

Animal and Range Science Department

Montana State University, Bozeman

Paul T. Tueller

Director

Knudtsen Renewable Resources Center

University of Nevada, Reno

Warren Whitman

Botany Department

Agricultural Experiment Station

North Dakota State University, Fargo

Socioeconomic/Legal/Environmental

Work Group

Harvey Banks

Consulting Engineers, Inc.

California

Bruce Beattie

Department of Agricultural Economics

Montana State University, Bozeman
—

Bruce Godfrey

Department of Economics

Utah State University, Logan

Joe Goodin

Department of Biological Sciences

Texas Tech University, Lubbock

Marvin Jensen

Fort Collins, Colo.

Ron Lacewell

Department of Agricultural Economics

Texas A&M University, College Station

Dwight Metzler

Kansas Department of Health

FIELD PLANNING

Dryland Agriculture-Denver, Colo.

Alfred L. Black

USDA Agricultural Research Service

Northern Great Plains Research Center

Mandan, North Dakota

Theodore Downing

Anthropology Department

University of Arizona, Tucson

James Engibous

Department of Agriculture and Soils

Washington State University, Pullman

Chester E. Evans

Fort Collins, Colo.

Richard Felger

Arizona-Sonora Desert Museum

Tucso n

Michael Glantz

National Center for Atmospheric Research

Boulder, Colo.

James Krall

Plant and Soil Science Department

Montana State University, Bozeman

Ronald Newton

Department of Plant Sciences

Texas A&M University, College Station

Robert W. Pearcy

Botany Department

University of California, Davis

App. F—Contractors, Work Groups, and Workshops . 401

— . — —.

Ray Moses

Moses, Wittemyer, Harrison, and

Woodruff, P.C.

Colorado

John Sheaffer

Sheaffer & Roland, Inc.

Illinois

Bill Stini

Department of Anthropology

University of Arizona, Tucson

Joe Warburton

Desert Research

Nevada

Institute

WORKSHOPS, 1981

Norman Rosenberg

Center for Agriculture, Meteorology, and

Climatology

University of Nebraska, Lincoln

Robert A. Stewart

USDA Agricultural Research Service

Conservation and production Research

Laboratory

Bushland, Tex.

Rangeland

Kay H. Asay

Agriculture-Salt Lake

City, Utah

USDA Agricultural Research Service

Crops Research Lab

Utah State University, Logan

Wilbert H. Blackburn

Range Science Department

Texas A&M University, College Station

Al A. Dyer

Department of Forest and Wood Science

Fort Collins, Colo,

Richard E. Eckert

Renewable Resources Center

University of Nevada, Reno

James E. Ellis

Natural Resources Ecology Lab

Colorado State University, Fort Collins
402 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands ——-— . — — ..— ——————— —..———-.—— ——

Dennis Hansen

Plant Resources Institute

Salt Lake City, Utah

Floyd E. Kinsinger

Society for Range Management

Denver, Colo.

John L. McLain

Resource Concepts, Inc.

Carson City, Nev.

David R. Patton

Rocky Mt. Forest and Range Experiment

Station

Forestry Sciences Laboratory

Arizona State University, Tempe

William Sisson

USDA

New Mexico State University, Las Cruces

Irrigation Agriculture-Berkeley,

Calif.

Lars W. J. Anderson

USDA Aquatic Weed Control Research Lab

University of California, Davis

Neil H. Berg

Pacific Southwest Forest and Range Experiment

Station

U.S. Forest Service

Berkeley, Calif.

Sheldon Boone

USDA Soil Conservation Service

Denver, Colo.

Brent Cluff

Water Resources Research Center

University of Arizona, Tucson

William Ehrler

U.S. Water Conservation Lab

Department of Agriculture

Phoenix, Ariz,

Paul E. Fischbach

Department of Agricultural Engineering

University of Nebraska, Lincoln

Robert M. Hagan

Department of Land, Air, and Water Resources

University of California, Davis

R. Keith Higginson

Higginson & Associates, Inc.

Salt Lake City, Utah

James B. Kendrick

Agriculture and University Services

University of California, Berkeley

Gary Nabhan

Meals for Millions Foundation

Tucson, Ariz.

J. Herbert Snyder

Water Resources Center

University of California, Davis
Index
Index

Agricultural Computer Network (AGNET), 327

Agricultural Statistics, 33

agricultural surpluses, 42

Alaska, 12, 188

All-American Canal, 123

American Heart Association, 93

American Indians, 25, 181, 261

American Medical Association Advisory Panel on

Toxic Substances, 98

Appalachian Mountains, 162

Argentina, 265

arid and semiarid lands:

alternative agriculture, 322

animals for, 263

basic and applied research, 19

definition of, 30

ground water (see ground water)

irrigation (see irrigation

land area, 30

natural features of, 351

potential new crops, 258

regions of the United States, 3, 30

vegetation types, 37, 261

Arizona, 30, 35, 38, 39, 41, 56, 66, 75, 90, 119, 120,

121, 123, 129, 130, 132, 134, 135, 138, 157, 161,

201, 263, 283, 386

Arizona Department of Water Resources, 135

Arizona-Sonora Desert Museum, Tucson, Ariz., 322

Arkansas River, 60, 70, 73, 76, 189, 274

Arkansas, White, and Red River Basins, 364

Australia, 156, 266

“Blueprint for a Dryland Democracy, ” 110

Bonneville Power Administration, 185

Brazil, 265

Brazes River, 75, 204

Bredehoeft, J., 73

California, 30, 31, 33, 34, 35, 37, 38, 39, 41, 56, 60,

70, 73, 74, 75, 76, 79, 87, 89, 99, 116, 121, 123,

130, 132, 134, 151, 156, 157, 161, 182, 263, 273,

282, 283, 307, 325

California Basins, 378

California Joint State-Federal River Forecast Center,

171

California Water Resources Control Board, 86

Canada, 60

carbon dioxide (C02

), 63

Carter administration, 67

Cascade Mountains, 30, 40, 52, 53, 60, 61

Census of Agriculture, 33

Central Arizona Project (CAP), 124, 291, 293

Central Valley Project, Calif., 184, 291, 293, 352

Chile, 266

Cincinnati, Ohio, 97

cloud seeding (see weather modification)

Colorado, 30, 33, 35, 37, 38, 39, 56, 74, 75, 119, 120,

121, 123, 129, 130, 131, 132, 156, 157, 160, 161

Colorado-Big Thompson project, 12, 136, 188

Colorado Ground Water Commission, 131

Colorado Plateaus, 382

Colorado Rivers, 60, 62, 63, 66, 70, 71, 73, 76, 85,

124, 188, 274, 383

Colorado River Basin, 228, 370

Colorado River Basin Pilot Project Final

Environmental Statement, 158

Colorado River Compact, 66, 120, 123, 124

Columbia Basin Irrigation Project, 131

Columbia Lava Plateau, 382

Columbia River, 60, 76, 79, 120, 134, 172

Columbia River Operation Hydromet Management

System (CROHMS), 185

Columbia River Valley, 56

computers and information management:

agricultural extension services, 18

data bases, 22

Federal data storage systems, 22

Federal funds, 22

private sector, 22

recordkeeping, 18

Congress:

Congressional Budget Office (CBO), 25, 26, 347

General Accounting Office (GAO), 281, 291, 293

Office of Technology Assessment (OTA). 19, 66

Select Committee on Disadvantaged People and

Renewable Resources, 25

Senate Select Committee on Water Resources, 67

congressional interest, 3, 18, 19, 20, 21, 22, 23, 24,

25, 26

issues and options:

achieving equity in water availability and

distribution, 345

impacts of water pricing on the adoption of

technology, 346

improving the effectiveness of water-related

technologies, 347

need for an interdisciplinary program of basic

and applied research, 334

need for a strong Federal role in water quality,

341

need to have reliable ongoing information about

renewable natural resources, 335

need to integrate water-related agricultural

activities in Government agencies, 21, 337

protecting and maintaining long-term

productivity of rain-fed agricultural resources,

343

Cornell University, Department of Agronomy, 91

Dalles Dam, 120

Department of Agriculture (USDA], 7, 20, 26, 33, 47,

69, 97, 261, 338

Agricultural Research Service, 48, 300, 338

Bureau of Agricultural Engineering, 172

Cooperative Extension Service, 328

field research stations, 24

405
406 . Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

— . -—— .—— —— —-

Office of the Secretary, 22, 123, 338

Salinity Laboratory, 280

Secretary John R. Block, 42

Soil Conservation Service (SCS), 48, 81, 172, 173,

182, 230, 253, 300

Department of Commerce, 7, 47, 69

Bureau of the Census, 33

National Oceanic and Atmospheric Administration,

48, 69, 156, 172

National Weather Service, 48, 171, 172, 185

Department of Defense, 7, 47, 69

U.S. Army Corps of Engineers, 48, 172, 182, 185,

188, 189, 190

Department of Energy, 7, 69

Department of the Interior, 7

Bureau of Land Management, 48, 203, 313, 317,

339

Bureau of Reclamation, 48, 120, 131, 156, 172, 182,

185, 194, 228

National Water Data Exchange, 48, 68, 69

National Water Summary, 67

office of Water Policy, 67

Office of Water Research and Technology, 47, 67,

334

U.S. Fish and Wildlife Service, 48, 323

U.S. Forest Service, 48, 161, 163, 339

U.S. Geological Survey, 48, 68, 69, 70, 71, 75, 101,

121, 173, 182, 185, 280, 283, 307, 338

Department of Transportation, 7

Dust Bowl, 35, 42

economic values of Western water, 338-391

Environmental Data Information Service, 69

Environmental Protection Agency, 7, 48, 69, 86, 94,

98, 102, 135

farm marketing, cash receipts, 353

Federal institutions, preparedness, 18, 19

Federal Inter-Agency River Basin Committee, 67

Federal Water-Data Colelction Agencies (table 1], 7

Federal Water Pollution Control Administration, 86

Fort McDowell Indians, 120

Fourth National Groundwater Quality Symposium, 89

future energy demands, 80-81

Galapagos Islands, 266

Gila Desert, 56

Gila River, 77, 98

Great Basin, 75, 76, 374

Great Plains, 24, 30, 31, 33, 35, 37, 38, 40, 41, 53, 54,

80, 256, 259, 301, 351

ground water:

artificial recharge, 16, 275, 282, 283, 284

calcium, 16

contamination, 16, 17, 89, 90, 267

definition of, 56

depletion of, 14, 16, 41, 73, 274

development of, 62

dissolved minerals in, 279

effects of overdrafting, 291

energy costs for pumping, 286

improving withdrawal efficiency, 285, 287

increasing supplies, 282

law, 113, 116

magnesium, 16

mining, 6, 16, 73, 77, 81, 136, 274, 292, 293

municipal and industrial use, 17

public health, 17, 23

quality (see water quality)

recharge basins, cost of, 283

recharge wells, 283

relationship with surface water, 276

resource regions, 56, 59, 276, 277, 380

seepage, 50, 275

social costs, 17

special characteristics, 290

subsidence, 16, 293

table, 50

technologies affecting, 16, 273

upward capillary movement, 50

use, 273

water spreading, 282

well efficiency, 287, 288, 289

Gulf Coastal Plain, 56

Gulf of Mexico, 50

Hawaii, 30

hazardous waste sites by State, 384

High Plains Associates, 274

High Plains Underground Water Conservation

District No. 1, 286

Hoover Dam, 123

hydroelectric generation (see water use)

hydrologic cycle, 3, 6, 9, 10, 11, 47, 48, 80, 113, 150,

164, 181, 309

atmospheric moisture, 53

data bases, 7

evaporation, 49, 230

evapotranspiration, 53, 54, 56, 57, 150

human intervention, 66

infiltration, 50, 56

measurement techniques, 64, 65, 66

percolation, 50, 56

plants, 243

precipitation, 49, 52, 53, 54, 56, 57

runoff, 50, 56, 60

soil water, 211

transpiration, 50, 230

variability, 61, 66

watershed, 50, 151, 160, 161

hydrologic zones, 52

Hydrometeorological Streamtlow Prediction (HM),

172, 173

Idaho, 30, 33, 35, 37, 38, 39, 75, 119, 121, 129

Illinois, 97

Interior Basin, 351

International Agency for Research on Cancer, 92

International Boundary and Water Commission, 7, 69

irrigation, 5, 6, 9, 12, 13, 14, 16, 34, 79, 134, 287
Index ● 4 0 7

— ——.—

acreage, 40

conservation, 230

definition of terms, 229

development in Great Plains, 37

economic values, 174, 388

energy costs, 141, 259, 285, 286

fuels used for, 287

impacts of, 130, 131

methods, 231, 232, 233, 234, 235, 236

onfarm reservoirs, 184, 191, 194

purposes, 38

quality of water, 87, 93

reuse of wastewater, 88, 309

scheduling, 17, 302, 303

social ramifications, 41

system management, 237

training, 195

water distribution procedure, 192, 193, 194

Israel, 18, 304

Kansas, 5, 30, 31, 34, 35, 38, 39, 75, 119

Kings River, Calif., 192

Land Institute, Salina, Kans., 322

land-use management technologies:

alternative agriculture, 18, 322, 323

animal mixtures on rangelands, 18, 321

brush management, 319, 320, 321

computers, 327, 328, 329

Federal efforts, 22

fisheries, 314

multiple use of croplands, 324, 325

multiple use on rangelands, 17, 313

nonforage plant products, 315

nonmeat animal products, 315

plants and animals, 317, 319

reclamation, 315, 316, 317

recreation, 315, 325

revenue from hunting and fishing, 325

wildlife, 314, 325

Lathrop, Calif., 99

legislation:

Arizona Groundwater Management Act, 386

Boulder Canyon Project Act of 1928, 123

California Limitation Act of 1929, 123

Carey Act of 1894, 110

Clean Water Act, 23, 102, 122, 123, 300, 342

Colorado River Basin Project Act of 1968, 191

Columbia Treaty of 1964, 124

Comprehensive Environmental Response, Compensation, and Liability Act, 102

Desert Land Act of 1877, 109

Federal Insecticide, Fungicide, and Rodenticide Act

(FIFRA), 97

Federal Land Policy and Management Act of 1976,

153, 339

Federal Reclamation Act, 1902, 67, 111

Federal Water Pollution Control Act of 1972, 122,

300

Homestead Act of 1862, 109, 111

Mexican Water Treaty, 124

Multiple Use, Sustained-Yield Act of 1960, 153, 339

National Environmental Policy Act (Public Law

91-190), 135

Native Latex Commercialization Act of 1978, 263

Plant Variety Protection Act, 1970, 15, 254

Reclamation Safety of Dams Act of 1978, 191

Resource Conservation and Recovery Act (RCRA),

120

Safe Drinking Water Act, 102

Water Resources Development Act of 1976, 275

Water Resources Planning Act of 1965 (Public Law

89-90), 47, 67, 111

Water Resources Research Act of 1964 (Public Law

88-379), 67

Lower Colorado River Basin, 150, 174

method of OTA study, 393

Mexican Water Treaty, 191

Mexico, 123, 124, 263, 267, 310

Miami, Fla, 97

Minnesota, 256

Mississippi River, 50, 60

Missouri River, 12, 53, 61, 70, 71, 73, 76, 77, 97, 149,

188, 189, 274

Missouri River Basin, 362

Montana, 30, 35, 38, 39, 119, 120, 121, 129, 301

Montana River, 60

Montana Water Code, 117

National Academy of Sciences, 87, 97, 99, 261

national agricultural policy, 18

National Agricultural Research and Extension Users

Advisory Board, 348

National Cancer Institute, 94

National Center for Atmospheric Research (NCAR),

20, 335

National Center for Water Resources Research, 19,

20, 334

National Conference of State Legislatures, 385

National Drinking Water Advisory Council, 89

National Interim Primary Drinking Water Regulation,

94

National Organic Reconnaissance Survey, 94

National Research Council, 64, 87, 93, 314

National Science Foundation, 258, 261, 335

National Stream Quality Accounting Network

(NASQAN), 101, 102

National Water Assessment, 1968 and 1978, 47, 62,

67, 74, 75, 79, 80

National Water Commission, 47, 67, 69, 274

national water policy, 18

Navajo Indian Irrigation Project, 120

Nebraska, 5, 30, 31, 34, 35, 38, 39, 75, 77, 116, 119,

273

Nebraska Natural Resources Information System, 69

Negev Desert, 267

Nevada, 5, 30, 31, 33, 35, 38, 39, 73, 119, 120, 121,

129, 156

New Mexico, 30, 35, 38, 39, 74, 75, 90, 116, 119, 121,

123, 129, 130, 319

New Orleans, La., 97
408 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

. — —

New Zealand, 266

North Dakota, 30, 34, 35, 38, 39, 119, 156, 157, 256

North Platte River, 77, 78

Nuclear Regulatory Commission, 7, 69

Ogallala aquifer, 35, 130, 131, 132, 141, 181, 273, 274,

275, 382

Ohio River, 60

Oklahoma, 30, 35, 38, 39, 119, 156, 319

Olympic Peninsula, 53

Oregon, 30, 33, 35, 37, 38, 39, 56, 60, 79, 119, 120,

122, 161

Organic Gardening and Farming Research Center,

Emmaus, Pa., 261

Orme Dam, 120

Ouachita River, 189

Pacific Northwest, 16, 50, 53, 56, 79, 75, 134, 151

Pacific Northwest Basin, 376

Pacific Northwest Water Resources Region, 79

Papago Indians, 170

payment-in-kind (PIK) program, 42

Peru, 266

Plans for Water Data Acquisition by Federal Agencies Through Fiscal year 1983, 48

plants and animals:

animal breeding:

artificial insemination, 254

buffalo, 263

cattle industry, 256

computerized recordkeeping, 15

embryo storage and transfer, 15, 255

feedlots, 15, 254

“new” animals, 16, 259

programs, 254

rabbits, 263

ruminant farm animals, 15, 254

sheep and goats, 15, 254

biotechnologies:

bacterial osmoregulation, 251

genetic diversity, 14, 15

institutional constraints, 14, 247

private sector research, 15, 247

protoplasm fusion, 14, 246, 247, 250

recombinant DNA, 14, 246, 247, 248, 250, 251

tissue culture, 14, 246, 247, 248, 249, 266

drought-resistant plants, 14, 15, 252

germplasm, 15, 254, 257, 258, 267

halophytes, 265

legal barriers, 259, 261

plant breeding:

economic yield, 253

micro-organisms, 266

philosophical basis, 251

potential new crops, 257, 258

six steps, 251

sunflowers, 256

water stress, 15, 253

plants for biomass energy, 262

plants for industrial products, 263

salt-tolerant organisms, 264, 265

promising crop candidates:

amaranth, 16, 261

buffalo gourd, 16, 258, 262

cowpea, 16, 261, 262

guar, 16, 263

guayule, 16, 258, 263

jojoba, 16, 258, 260, 263

mesquite, 16, 262

milkweed, 16, 259, 263

saltbush, 16, 262

tepary bean, 16, 245, 258, 261

Population Reference Bureau, 129

Powell, John Wesley, 110

President’s Scientific Advisory Committee, 98

Project Skywater Programmatic Final Environmental

Statement, 158

Puerto Rico, 30

Pyramid Lake Paiutes, 120

rain-fed agricultural resources:

congressional interest, 343

conversion of rangeland, 24

cultivating marginal or unsuited lands, 24

dryland and rangeland research, 24

research and development, 24

Reagan administration, 47

Reagan, President Ronald, 67

Red River, 60, 70, 73, 76, 189, 274

research and development (R&D), 3, 24, 174, 328

Resources for the Future, 293

Rhoades, J. D., 228

Rio Grande Basin, 368

Rio Grande River, 60, 70, 73, 76, 124, 274

Rio Grande Valley, 56

Rock Springs District, Wyoming, 203

Rocky Mountains, 56, 77, 81, 151

Rodale Research Center, 322

Sacramento River Forecast Center, 171

San Joaquin Valley, Calif., 40, 294

Seattle, Wash., 97

Sierra Cooperative Pilot Project Environmental

Assessment, 158

Sierra Mountains, 52, 60

Six State High Plains-Ogallala Regional Resources,

study, 188, 275

Snake River, 60, 61, 75, 273, 283

soil-water relationships:

basin tilage, 217

capillary rise, 212

changing soil properties:

chemical soil conditioner materials, 225

harvester ants and termites, 226

micro-organisms, 225

mycorrhizae fungi, 226

soil conditioners, 226

contour furrowing, 217

crop considerations, 236

deep plowing, 216

drip irrigation, 234, 236

evapotranspiration, 212
Index ● 4 0 9 —

Great Plains, 213

hydrologic cycle, 211, 212

infiltration, 211, 215

irrigated agriculture, 227, 229

irrigation terms, definition of, 229

land leveling, 218, 219

land-shaping practices, 216

leaching, 228

limited irrigation, 236

managing soil cover:

crop residues, 220, 223

fallow systems, 219

modification of plant canopies, 225

mulches, 219, 220

plant-barrier systems, 223

saline seeps, 221, 222, 223

mechanical land treatments, 216, 217

movement, 211

onfarm irrigation efficiencies, 232

onfarm salinity management, 229

site conditions, 211

soil salinity, 228, 229

soil textures, 213

sprinkler irrigation, 234, 235

subsurface irrigation, 235, 236

supplies, 211, 213

supplying full water needs to plants, 231

surface irrigation, 232, 233

technologies affecting, 13

application costs, 14

Federal/State restrictions, 14

terraces, 218

use of precipitation, 215

vegetation, 211

South African, 266

South Dakota, 30, 35, 38, 39, 119, 122, 256

South Platte River, 77, 78

Soviet Union, 256

Stegner, Wallace, 110

stream flow:

average for major rivers, 60

Colorado River, 66

data, 174

forecasting, 170, 172, 174

spatial pattern, 61

variability, 62, 63

Streamflow Synthesis and Reservoir Regulation

(SSARR), 172

surface water (see also ground water):

law, 113, 114

monitoring, 101

nonconsumptive use, 79

quality (see water quality: ground water)

reuse, 75, 77

runoff, 50, 56, 60, 150

use, 273

watershed management, 159

Tennessee River, 60

Tennessee Valley Authority, 7, 69

Texas, 7, 16, 30, 34, 35, 38, 39, 90, 119, 129, 156, 157,

273, 319

Texas-Gulf Basins, 366

Texas-Gulf region, 7, 60, 70, 76, 81, 294

Texas-Gulf Water Resources Region, 72

Texas Natural Resources Information System, 69

Tulare Basin, California

Tijuana River, 124

Umatilla reservation, 120

University of California, Santa Cruz, 322

University of Nebraska, 324

Upper Colorado River Compact, 120, 123

Upper Colorado River Water Resources Region, 72

U.S. Public Health Service, 93

U.S. Supreme Court, 116, 120

U.S. Water Resources Council, 47, 50, 67, 70, 274,

334

Utah, 30, 33, 35, 37, 38, 39, 90, 119, 120, 122, 123,

129, 156, 157, 160

Utah Division of Water Rights, 69

van Schilfgaarde, J., Director, U.S. Salinity Laboratory, 228

Virgin Islands, 30

Wagon Wheel Gap, Colo., 161

Washington, 30, 31, 35, 37, 38, 39, 56, 60, 71, 79, 119,

122, 131

Water Data Storage and Retrieval System, 69

water-management technologies:

aquiculture, 312

“Best Management Practices, ” 300

computerized agricultural models, 300

conjunctive use of surface and ground water, 17,

309, 311

crop-management model, 301

enclosures for plants and fish, 17, 43, 310, 312

Federal efforts, 17, 22

flexible cropping, 17, 300, 301

in Israel, 304

irrigation scheduling, 17, 302, 303

wastewater;

reuse of, 17, 304, 308

treatment, 305, 306, 307, 308

watershed, 175

Water Policies for the Future, report to the President,

1973, 47, 67

water quality:

algae “bloom,” 87, 91, 92, 94

agricultural chemicals, 8, 16, 86, 95, 97

“black alkali,” 88

boron, 88

brine disposal, 12

calcium, 88, 279

chloride, 88, 279

control of toxic and noxious substances, 1 6

criteria, 86

desalination, 12

dibromochloropropane (DBCP), 87
410 ● Water-Related Technologies for Sustainable Agriculture in the U.S. Arid and Semiarid Lands

. — —.—— —.———— -

drinking water, 23, 87, 90, 93, 97, 99, 278

Drinking Water and Health, 87

Federal role, 23

ground water, 16, 23, 274

dissolved materials in, 279

drinking water, 278

effects of human activity, 281

monitoring, 281

salts, 278

technologies to improve, 284

virus contamination, 89

hardness, 279, 280, 281

heat, affects on, 90

high standards, need for, 2 3

industrial shopping, 23

integrated analysis of contamination, 8

law (see Western water law)

magnesium, 88

management practices, 8, 23

mining activities, 315

monitoring and control, 8, 23, 101, 102

pollution, 7, 16, 23, 63, 87

problems, 85, 86

radioactive substances, 90

regulations:

best management practices, 123

Federal involvement, 122

point and nonpoint source pollution, 122

riparian zones, 13

salinity level for livestock, 87

salts, 8, 16, 85, 86, 87, 88, 93, 130, 187, 278

sodium, 88, 93, 279, 281

Sodium Absorption Ratio (SAR) index, 280

sulfate, 88, 279

suspended and dissolved solids, 85

trace element tolerances for irrigation waters (table

18), 89

treatment, 8, 9, 22, 94, 305

well water, 8

water-treatment:

carbon tetrachloride, 94

carcinogens, animal, 94, 97, 99

carcinogens, human, 92, 94

cyclodiene insecticides, 97, 98

chloroform, 94

epidemiological studies, 94

dioxin, 98

herbicides, 98

maximum contaminant level (MCL), 94

oxygen-demanding wastes, 94

toxic byproduct, 98

trihalomethanes, 94

water resources:

agricultural effects on, 91, 92, 93

analyses, 67, 68, 70, 138

climatic fluctuations, 7, 63, 64, 66

competition for, 5, 132, 133

conservation, 6, 9, 11, 12, 13, 25, 191, 215, 230

consumption, 8, 9, 72, 73, 139

data collection, 67, 68, 70

depletion, 5, 35

efficiency of plants and animals, technologies

affecting, 1 4

(see biotechnologies)

energy and mining use, 132

estimate of supply, 6, 63, 72, 73

estimating water prices:

alternative cost, 139

change in net income, 139

consumer surveys, 139

direct observation of markets, 139

ex post statistical analysis of water-use behavior,

139

Federal data-collection agencies, 69

Federal involvement, 9, 18, 19, 25, 26, 67, 68, 69

Federal, State, and local spending for, 112, 184

ground water (see ground water)

habitat maintenance, 6, 22, 79

instream flow, 22, 72

major region of the United States, 67

mountain snowpack, 7, 10, 61, 71, 81, 150, 171

municipal use, 134

offstream uses, 6, 79

planning and management, 19, 67, 138, 387

precipitation, 9, 11, 13, 49, 149, 150, 155, 156, 176,

215

problems in setting water values:

annual rental value or future income, 140

changing values during crop production, 140

comparing values in place, form, time, 140

indirect effect from water development, 140

marginal v. total value, 139

measuring quantity, 140

quality (see water quality)

regional characteristics, 355

regional interaction, 19

regions of the Western United States (fig. 9), 51

return flow, 8

reuse, 8, 75, 77, 304, 305

scarcity, 137

State initiatives in planning, 385

storage facilities, 11, 62

subregions, 74, 76

surface runoff, 10, 11, 50, 56, 60, 61, 71, 149, 171

measurement, 65

volume in West, 7, 11, 66, 138

water market, 136

water measurement, 64, 65, 66

water value, 138, 139

waste assimilation, 6, 79

weather modifications, 7, 10, 26, 154, 155, 175

Water Resources Scientific Information Center, 69

Water Salinity Control Project, Yuma, Ariz., 124

watershed management, 22, 50, 149, 150

highland, 26, 152

alpine zone, 10, 151, 153, 159 160, 175

montane forest, 10, 151, 153, 159, 160, 175

impacts of management technologies, 151

lowland, 10, 151, 152, 164, 175

research, 161, 166
— ——— . . .

Index ● 4 1 1

— .

snowmelt, 159

transition zones, 153

vegetation management, 161, 163, 164

vegetation removal or replacement, 10

water yield, 163

wet and dry years, 62

wilderness values, 10

“Water Quality Criteria,” 86

water storage and delivery:

automated upstream control, 193

catchments, 168, 169

compartmented reservoirs, 13, 199, 200

dams, 182

delivery of surface water to irrigation users, 12

desalting plants, 188

desalination (see water quality)

downstream control systems, 194

environmental effects, 186

evaporation control:

mechanical covers, 13, 199, 200

reflective coatings, 13, 199

surface area reductions, 13, 199

surface films, 13, 199

facilities, 11, 169, 182

farm and ranch ponds, 11, 12, 184

Federal role, 11, 186

financing, 184, 186

imports and exports, 189

interbasin transfer, 12, 188

interstate transfer, 190

regulating reservoirs along irrigation canals, 194

reservoirs, 11, 13, 62, 182, 184, 186

rigid surface linings, 197

soil sealants, 197

surplus water, 12

technologies that conserve supplies:

flexible delivery systems, 12, 191

seepage and evaporation control, 12, 195, 196

vegetation management, 12

tradeoffs, agricultural and wildlife, 199

vegetation management, 13, 161, 163, 164

aquatic plants, 13, 202, 203, 204, 206

chemical use, 13, 165, 202, 205, 206

mechanical controls, 202, 203

pest control, 205

saltcedar, 204

water use:

adoption of technology, 8

agronomic WUE, 244, 246, 252

animals adaptation to limited water supply, 14, 244,

245, 246

beneficial use, 9, 281

biological WUE, 244

conjunctive use of surface and ground water, 17,

309, 311

conservation, 9, 25, 118

decisionmaking, 24

efficiency of, 9, 70

equity, 24

Federal reserved rights doctrine, 25

Federal subsidies, reduction of, 25

fish habitat, 79, 140

forecast models, 11

growing demands, 9

hydroelectric generation, 6, 22, 72, 73, 75, 79, 81,

140, 174, 390

Indian reserved water rights, 25

irrigation (see irrigation)

legal system, 8

local economics, 9

market system, 8, 135

nonconsumptive use, 140

off stream consumption by States, 71, 75

per capita consumption, 72

plants (see biotechnologies)

recreation, 6, 22, 79, 80, 136, 137, 140, 314

regional patterns, 47

resource protection, 135

States concern, 9

streamflow forecasting, 7, 11, 22

supply/use patterns, 75

user oversight groups, 26

wastewater, reuse of, 17, 304, 305

water-use rights, 8, 24, 25

Western history and development, 109, 110, 111

weather modification:

assessment of, 158

cloud seeding, 10, 154, 155, 175

cumulus air masses, 155

cumulus clouds, 156, 175

natural precipitation efficiency, 156

orographic air masses, 155

seedability potential, 157

silver iodide, 155

warm seeding, 155

Western agriculture:

agricultural chemicals, 95-99

agronomy, 9

animals (see plants and animals)

augmenting water supplies, 9

brush control, 165, 166, 168

Chaparral-dominated rangelands, 167

competition for water, 133

competition with nonagricultural uses, 41

contaminants, 24

conventional crops, 266

corporate farms, 40

crop specialization, 31

dissolved salts, 92

diversity, 29

dryland, 5, 14, 24, 34, 35, 214, 219, 223, 317

High Plains area, 131

major producing areas, 37

“duty of water,” 135

economic efficiency and agricultural technology,

141

equity and fairness in decisionmaking, 5, 24

erosion, 17, 163

exports, 29, 34, 354

farm size and ownership, 39
412 ● Water-Related Technologies for Sustainable Agriculture in U.S. Arid and Semiarid Lands

— —

Federal role, 3, 5 systems approach to decisionmaking, 5

federally owned land, 5, 31 trends, 41

hydrology, 9 Western water law:

income, farming and ranching, 5, 31, 39 appropriation doctrine, 114

irrigation (see irrigation) “basin of origin” statutes, 114

labor: common law doctrines, 116

costs, 40 correlative rights, 114

migrant workers, 41 doctrine of prior appropriation, 116

minorities, 41 doctrines, 9, 116

role of, 40 El Paso v. Reynolds, 116

long-term future, 41 Interstate and International Agreements, 123

mesquite-dominated rangelands, 168 Sporhase, et al., v. Nebraska, 116

national context, 31 State level, 113

natural features, 31 summary of, 115

Pinyon-Juniper dominated rangelands, 167 surface and ground water, 113

products of, 31 weather modification, 157

public land, 5 Western water rights:

livestock grazing, 5 Arizona v. California, 120, 123

rangeland, 5, 14, 24, 34, 214, 223, 316 atmospheric moisture, 125

animal mixture, 321 contractual arrangements, 117

brush management, 319 Federal doctrine, 118

forage, 36 irrigation, 117

multiple products, 37 permit system, 117

vegetation types, 36 public trustee, 119

related industries, 29, 34 quantification, 119, 120

resource base, long-term productivity return flow, 117

runoff agriculture, 168 State officer, 117

rural economics, 129 transfer of, 117

sagebrush-dominated rangelands, 166 Western Indian, 119, 120, 121, 122, 132

salt-tolerant crops: Winters v. United States, 119

algae, 16, 266 White River, 60, 70, 73, 76, 189, 274

bacteria, 16, 267 Wild and Scenic Rivers System, 191

blue-green algae, 16, 267 World Health Organization (WHO) United Nations,

development of, 264, 265, 266, 267 89

schematic of, 36 Wyoming, 30, 33, 35, 38, 39, 119, 122, 123, 129, 201,

seed and nursery stock, 29 261

selected major crops, 33 Wyoming Legislature, 117

socioeconomic factors, 125, 127, 128, 129, 130

soil compaction, 17 Yellowstone River, 64, 77, 78

soil salinization, 14, 264 Yuma, Ariz., 187

sustainability, 9

U.S. GOVERNMENT PRINTING OFFICE: 1983 O - 25-160 : QL 3