A

UNITED STATES DEPARTMENT OF AGRICULTURE • FOREST SERVICE

WASHINGTON OFFICE • FS-660 • JANUARY 2000

Water 

&

The Forest Ser orest Service
B
I

Contributors:

Mike Ash Engineering, WO

Enoch Bell Pacific Southwest Research Station

Tom Brown Rocky Mountain Research Station

Dave Cross Wildlife, Fish, and Rare Plants, WO

Ed Dickerhoof Resource Valuation and Use Research, WO

Mary Ellen Dix Forest Health Protection, WO

Steve Glasser Watershed and Air, WO

Dave Hohler Pacific Northwest Research Station

Jim Keys Watershed and Air, WO

Russ LaFayette Watershed and Air, WO

Keith McLaughlin Watershed and Air, WO

John Nordin Cooperative Forestry, WO

Doug Ryan Wildlife, Fish, and Watershed Research, WO

Larry Schmidt Rocky Mountain Research Station, Stream Systems Technology Center

Rick Swanson Watershed and Air, WO

Paul Tittman Lands, WO

USDA Forest Service

Policy Analysis

P.O. Box 96090

Washington, DC 20090-6090

James Sedell, National Interdeputy Water Coordinator, PNW

Maitland Sharpe, Policy Analysis, WO

Daina Dravnieks Apple, Policy Analysis, WO

Max Copenhagen, Watershed and Air, WO

Mike Furniss, Rocky Mountain Research Station, Stream Systems Technology Center

Water & The Forest Service
II
III

Contents

Summary i

Healthy forests are vital to clean water i

Maintaining and restoring watersheds were primary reasons for establishing the national forests i

Water is the central organizer of ecosystems i

Questions about the role of forests in water supply ii

Issues and policy iv

Interplay among issues v

Water Quantity and the National Forests 1

World water supply 1

The quantity of water from forested lands 2

Determining a water value for the National Forest System 5

True value of water is underestimated 7

Many communities depend on water from the national forests 7

Water Quantity Issues for Forest Planning 10

Streamflow regimes, timing, and floods 10

Augmenting streamflow 11

Instream flow requirements 12

Policy Implications 12

FERC relicensing 13

Groundwater 15

Policy Implications 15

Water Quality 16

Total maximum daily loads 16

Abandoned mine lands and hazardous materials sites 17

Watershed Condition and Restoration 18

Wetlands and riparian areas 18

Roads 19

Conserving Aquatic Biodiversity and Threatened Species 21

Integrating Watersheds From the Headwaters Through the Cities 23

Policy Implications 23

Next Steps 24

References 25
IV
i

Public concern about adequate supplies

of clean water led to the establishment

in 1891 of federally protected forest

reserves. The Forest Service Natural

Resources Agenda is refocusing the agency on its

original purpose. 

This report focuses on the role of forests in water

supply—including quantity, quality, timing of release,

flood reductions and low flow augmentation, economic value of water from national forest lands, and economic benefits of tree cover for stormwater reduction

in urban areas. 

HEALTHY FORESTS ARE

VITAL TO CLEAN WATER

Forests are key to clean water. About 80 percent of the

Nation’s scarce freshwater resources originate on

forests, which cover about one-third of the Nation’s

land area. The forested land absorbs rain, refills underground aquifers, cools and cleanses water, slows storm

runoff, reduces flooding, sustains watershed stability

and resilience, and provides critical habitat for fish and

wildlife. In addition to these ecological services, forests

provide abundant water-based recreation and other

benefits that improve the quality of life. 

MAINTAINING AND RESTORING WATERSHEDS

WERE PRIMARY REASONS FOR ESTABLISHING

THE NATIONAL FORESTS

Use and development of the water resources of the

United States underwent major changes during the

19th century in response to the growing demands of a

population that had increased nearly 20-fold since the

founding of the country. Westward expansion, and

navigable rivers, canals, and harbors for transportation transformed the Nation’s economy. As the Nation

experienced this period of massive development,

major problems emerged from overuse and poor management of its water resources:

■ Urban water supplies were a major source of 

disease.

■ The capacity of many lakes and streams to assimilate wastes was exceeded.

■ The survival of people living in arid or flood-prone

areas depended on unpredictable precipitation 

patterns.

The 1897 Organic Administrative Act said these

forest reserves were to protect and enhance water

supplies, reduce flooding, secure favorable conditions

of water flow, protect the forest from fires and depredations, and provide a continuous supply of timber

By 1915, national forests in the West had been

established in much the form they retain today. These

national forests, which included 162 million acres in

1915, were essentially carved out of the public

domain. At that time, few Federal forests were designated in the East because of the lack of public

domain. Public demands for eastern national forests

resulted in passage of the 1911 Weeks Act, authorizing the acquisition of Federal lands to protect the

watersheds of navigable streams. From 1911 to 1945,

about 24 million acres of depleted farmsteads, stumpfields, and burned woodlands were incorporated into

the eastern part of the National Forest System.

This report focuses on the role of forests in water

supply—including quantity, quality, timing of release,

flood reductions and low flow augmentation, economic value of water from national forest lands, and economic benefits of tree cover for stormwater reduction

in urban areas.

WATER IS THE CENTRAL ORGANIZER

OF ECOSYSTEMS

Throughout human history, water has played a central, defining role. It has sculpted the biological and

physical landscape through erosion and disturbance.

The amount, place, and timing of water are reflected

in the vegetative mosaic across the landscape. Water

has also played a key role in shaping the pattern and

type of human occupancy; routes of travel and transportation, patterns of settlement, and the nature and

scope of human land-use all owe their characteristics

largely to water regimes.

Conversely, social demands on the water resource

system have produced major effects on virtually every

aspect of that system including quality, quantity, distribution, and form (for example, white water vs.

impoundments).

The human uses and values of water shape how it

is managed, and the biological and physical characteristics of water shape human values and uses. Thus,

water resource management requires a systems

approach that includes not only all of the constituent

parts, but also the links, relations, interactions, consequences, and implications among these parts. 

Traditionally, water has been valued as an engine of

development and as the source of commodity and utilitarian values to society. It has sustained agricultural

Summary

P
ii

production, grown forests, and powered cities and

industries. Today, these values remain, but they have

been joined by a variety of others. Water is the basis

for many of the recreational and amenity values people

seek. Increasingly, science shows, and managers recognize, the key role of water flow regimes in ecosystem function and processes. Adequate flow and water

quality are essential to maintaining key fish species

and fisheries, which in turn, are sources of many economic, cultural, and spiritual values. 

Across the Nation, significant challenges to

resource managers, scientists, and citizens are presented by emerging conflicts over providing highquality, abundant flows of water to sustain a

burgeoning population, an agricultural industry, historic salmon runs, and populations of other threatened aquatic species.

QUESTIONS ABOUT THE ROLE OF

FORESTS IN WATER SUPPLY

How Much Water Comes 

from the National Forests? 

Excluding Alaska, about two-thirds of the Nation’s

runoff comes from forested areas. National forest

lands contribute 14 percent of the total runoff.

National forest lands are the largest single source of

water in the United States and contribute water of

high quality. More than 60 percent of the Nation’s

runoff is from east of the Mississippi River, where 70

percent of the Nation’s private and State forests are

located. National forests in the East are responsible

for 6 percent of this runoff. National forests in the

West provide proportionately more water (33 percent)

because they include the headwaters of major rivers

and forested areas of major mountain ranges. Forest

Service literature from the 1940’s to the present has

claimed that 50 to 70 percent of the Nation’s runoff

comes from national forest lands. It is now clear that

those claims are overstated. 

What is the Value of Water from 

National Forest Lands? 

We calculate the marginal value of water from all

national forest lands to equal at least $3.7 billion per

year. Annual value of water from national forest lands

is greatest in the Pacific Northwest and Pacific Southwest Regions, and lowest in the Southwest Region.

These values represent a lower limit on the range of

values attributable to waters flowing from the national

forests. The actual values of this water yield are almost

certainly higher, but how much higher is not known.

How Should Municipal 

Watersheds be Managed? 

One issue is whether municipal watersheds should be

placed under active or passive management regimes

to sustain supplies of high-quality water over the long

run. Many Forest Service specialists think that water

supplies can be best protected by actively managing

these watersheds to maintain forest vegetation and

watershed processes within their natural range of

variation. Conversely, many people in urban centers

believe that, in the interest of water quality and safety,

people should not alter watersheds in any way, other

than to divert the water. Scientific evidence indicates

that watersheds can be effectively managed for safe,

high-quality water and still provide other resource

outputs as byproducts. 

Can Forests be Managed to 

Improve Stream Flow? 

Flooding and sedimentation from cutover lands was

one of the primary reasons for establishing national

forests. The timing of water yields was also an important issue, especially the desire to augment late-season flows. 

Vegetative cover and on-site control measures

effectively reduce flood peaks. However, significant

shifts in the timing of late-season runoff are not likely

to be achieved through managing forest vegetation

and snow across national forest lands. Treatments

that restore slopes, meadows, and channels; increase

the routing time between precipitation and runoff;

and recharge ground waters can be expected to have a

greater effect in sustaining late-season flows. 

Although theory suggests that vegetation management can produce more streamflow, for a variety of

reasons, general water-yield increases through forest

management are likely to fall in an undetectable

range. The data suggest that relying on augmentation

from national forests will not be a viable strategy for

dealing with water shortages. Greater gains can be

made by reducing water consumption, improving conservation, and establishing water markets to allocate

scarce supplies more efficiently. Providing cold, clear

waters of high quality for aquatic organisms and

human use is probably the proper focus for managing

water on the National Forest System. There is relatively little management can do to increase total water

yield, but forest management can have major effects

Summary
iii

on water quality—affecting temperature, nutrient

loadings, sediment yields, and toxic contaminants.

What is the Agency’s Role in Protecting 

Instream Flow and Ground Water? 

The Forest Service must actively participate in the

processes that allocate surface water, ground water,

and water rights. To be effective, this participation

must be timely and of impeccable technical quality. 

Three needs stand out:

■ Forest plan revisions should incorporate instream

flow needs to maintain public values. When a State

undertakes a basin-wide adjudication of water

rights, all beneficial consumptive and instream

water uses on national forest lands should be

claimed in accordance with State and Federal laws.

■ Early and intensive collaboration among existing

and potential water users is likely to be the most

effective approach. Public and interagency collaboration in forest planning has great potential for

solving problems and achieving acceptable solutions, lessening the costly litigation common to

water rights issues. 

■ In many places, the Forest Service lacks the technical expertise in hydrology needed to protect

instream flows. Our present workforce of in-house

expertise must be conserved and enhanced if costly

failures are to be avoided. 

What is the Agency’s Role in 

Hydroelectric Relicensing? 

From the 1940’s to the 1960’s, 325 hydroelectric projects were licensed and built on the national forests.

These facilities have provided power and recreation

for the Nation. However, many of these projects have

also had significant adverse effects on national forest

resources. 

During the next 10 years, more than 180 of these

projects come up for relicensing. The relicensing

process presents the only opportunity for the Forest

Service to address resource damage, mitigate future

adverse effects, and significantly influence how these

projects will operate for the next 30 to 50 years.

Forest Service participation in the relicensing

process could strengthen mitigation and restoration

programs on national forest lands that would lead to

improved aquatic habitats and increased water quality. Estimates of these benefits to national forest lands

exceed a billion dollars. Potential benefits include new

and upgraded recreational facilities, restored instream

flow regimes, and enhanced habitats for aquatic and

terrestrial wildlife. The relicensing effort offers a costeffective, immediate means to address the goals outlined in the Natural Resources Agenda and Clean

Water Action Plan. 

What is the Agency’s Role in 

Conserving Aquatic Biodiversity? 

National forest lands and waters play a pivotal role in

anchoring aquatic species and maintaining biodiversity. More then one-third of national forest lands have

been identified as important to maintaining aquatic

biodiversity. Five recent, large-scale, ecosystem-based

Forest Service assessments identified networks of

aquatic conservation watersheds: the Northwest Forest Plan, the Interior Columbia Basin Ecosystem Management Project, the Tongass National Forest Land

Management Plan, the Sierra Nevada Framework Project, and the Southern Appalachians Assessment.

Such a commitment and a special effort of lands to

the purposes of aquatic species conservation could be

regarded as the core of the national forest aquatic and

biodiversity conservation strategy. 

Can the Watershed Condition on 

National Forests be Restored? 

The most comprehensive landscape-scale assessment

to date—the Interior Columbia Basin Assessment—

found that the momentum from past events will push

the system further from the desired condition over

the decades to come. Even with aggressive management, that momentum will not be overcome within

the next 100 years under projected funding. Progress

toward forest health restoration can be expected to

proceed very slowly. In the interim, vegetative composition and structure at the landscape scale will be

determined by unnaturally large, high-intensity fires.

These findings suggest that it will not be feasible to

restore all degraded areas. We will have to strategically focus restoration efforts on selected watersheds

where we can hope to make a meaningful difference.

What is the Role of Urban 

Forests in Water Supply? 

Counties classified as “urban” contain one-quarter of

the total tree cover of the coterminous United States.

Urban trees affect water quantity by intercepting precipitation, increasing water infiltration rates, and

transpiring water. They can materially reduce the rate

and volume of storm water runoff, flood damage,

stormwater treatment costs, and other problems

related to water quality.

Summary
iv

The Agency Challenge. 

The challenge for the Forest Service will be to simultaneously perform the following: 

■ Systematically restore damaged watersheds on the 

national forests.

■ Mitigate additional watershed damage from land

uses and the inevitable major wildfires. 

■ Foster partnership efforts to meet the most pressing watershed restoration needs when they fall

outside of national forest boundaries.

ISSUES AND POLICY

Maintaining supplies of clean water and protecting

watersheds were major reasons why public domain

forests and rangelands were reserved. It was the headwaters of the western rivers, and cutover and eroded

lands in the East, that became the National Forest

System. With passage of environmental laws, such as

the Clean Water Act and Endangered Species Act,

clear standards for water quality were set by Federal

and State agencies. Despite water quality

improvements resulting from applying these

standards, many streams in the Nation are still highly

altered from their natural cycles. Under human influences, neither the range of natural conditions nor the

full expression of ecological interactions between

aquatic and terrestrial ecosystems is permitted.

Many factors affect water quality, production, and

quantity. The national population will nearly double

within the next 50 years. America’s population is getting older, more ethnically diverse, and concentrated

in urban areas. The population of the West has

increased 50 percent in the last 20 years and is expected to increase another 300 percent by 2040. Much of

the West was unproductive as farmland until lands

began to be irrigated in the late 1930’s. As a result of

population growth, large-scale reliance on irrigation,

and a host of other factors that have increased water

use, water in western streams is generally over approSummary

Figure 1. National forest watersheds integrate multiple processes 

and issues that must be considered in aggregate. Isolated, 

single-issue solutions won’t work.

Water Treatment Facility

Town

Agriculture

Precipitation

Dam

Windstorm

Ridge

Ridge

Lake

Watershed Divide

Riparian Zone

Wetland

Percolation

Percolation

Roadway

Groundwater (aquifer)

Snowpack

Forestry

Industry

River

Earthflow

Landslide Tributaries
v

priated (Moody 1990, NRC 1992). In Oregon and

Washington, 40 to 90 percent of the land areas of individual national forests west of the Cascade Range crest

are in municipal watersheds. The population surge in

the West is increasing the diversion and consumption

use of water and, at the same time, demand for waterbased recreation (Brown et al. 1991). 

This trend will continue and intensify. Most recreation in national forests is associated with some body

of water (lakes, reservoirs, or streams). Recent publications (Gillian and Brown 1998) have more closely

linked instream-flow issues to recreational activities

and have described the complex relationships of

recreation uses and water. For example, even without

incorporating many of the economic facets of the

recreational uses documented in the arid West, the

value of instream flows for recreational fishing is

greater than the value of that water for irrigation

(Hansen and Hallam 1990). 

There are more than 180 non-Federal dams on

national forests that provide hydroelectricity as well

as recreation. These dams are due for relicensing in

the next 5 to 10 years. The Forest Service, under the

Federal Power Act of 1920, is legally bound to condition the licenses to mitigate the effects of these dams

on fish, wildlife, water quality, and recreation values.

The Nature Conservancy (1996) and other recent

assessments have described the deteriorating condition of freshwater species and ecosystems in the United States. More than 300 freshwater species are listed

or proposed for listing under the Endangered Species

Act. More than 37 percent of native fish species are at

risk of extinction, including all of the major populations of salmon and steelhead trout on the west coast

south of Alaska. National forest lands contain the best

habitat and strongest remaining populations of most

of the species at risk. The Nature Conservancy estimated that protecting and restoring 327 watersheds

(~800,000 acres each) or 15 percent of the total number of subbasins in the United States would conserve

populations of all at-risk freshwater fish and mussel

species in the country. National forest lands influence

181 of these watersheds and will be the anchoring

habitat for nearly all of the west coast salmon and

trout populations. 

INTERPLAY AMONG ISSUES

In addition to the agency’s need to consider each of

these issues independently, the interplay among them

must also be considered (see figure 1). For instance,

many of the reservoirs in national forests were built to

meet many different needs, including water for agriculture. On the west side of the Oregon Cascades, only 5

percent of the water that agricultural water rights

holders are entitled to has been claimed. If they begin

to claim more of their entitlement, flows, water quantity, and recreation will likely be affected in major ways.

Moreover, several species of salmonids already listed

under the Endangered Species Act need more water in

certain locales. Recognizing the loss of natural function and natural hydrologic regimes in these highly

altered streams, the Forest Service has been pursuing

Federal water rights and adjusting conditions in special-use permits to require bypass-flows. Changes of

the status quo in water appropriation deeply concern

western State governments and senior water-rights

holders. Regional climate shifts and global climate

change could further exacerbate these issues and confound them with other water issues.

Various Federal interagency water initiatives are

addressing aspects of these issues. But, to date, there

has been no effort to characterize the particular role

of national forest lands in supplying the Nation’s

water, or to define the role of Federal lands and water

in the matrix of State and private lands.

The Nation’s water resources face growing scientific, management, and political challenges. The Forest

Service will play a major role in these discussions,

improving the ability of policymakers, managers, and

citizens to develop options, anticipate consequences

and implications, and fashion responsive, informed

programs. ❖

Summary
vi
1

ORLD WATER SUPPLY

Although 70 percent of the Earth’s surface is covered with water, the amount of

fresh water available on land surfaces is

a tiny fraction of the total; 97.5 percent of the water

on the planet is in the oceans — too salty to drink or

to grow crops. Most of the 2.5 percent that is not salt

water is locked up out of practical reach in the vast

icecaps of Greenland and Antarctica. Less than 1 percent is fresh water, present in the form of groundwater, on the land surface, and in the atmosphere. Less

than eight ten-thousandths of 1 percent is annually

renewable and available in rivers and lakes for human

use including agriculture, and for use by aquatic

species (see figure 2).

Water is continuously cycled between the Earth’s

surface and atmosphere through evaporation and precipitation. The fresh water that falls on land as rain or

snow, or that has been accumulated and stored over

thousands of years as groundwater, is what people use

to meet most of their needs. That supply, although

replenished daily, is both limited and vulnerable to

human actions and abuse. Over-appropriated rivers

and excessive groundwater pumping are serious problems. Many of America’s important food-producing

regions are sustained by the hydrologic equivalent of

deficit financing—using water that is not being

replaced. The rational use and protection of water

resources are among today’s most acute and complex

scientific and technical problems. Shortages of fresh

water and the increasing pollution of water bodies are

becoming limiting factors in the economic development of many countries, even countries not in arid

zones. Under these conditions, assessing and managing water resources is vital. Reliable estimates of

annual streamflows, their fluctuations, and water

resources stored in lakes, aquifers, snowpack, and glaciers are critical to a clear understanding of natural

water cycles and the effects of human activities. 

All types of waters are renewed, but the rates of

renewal differ sharply. Water in rivers is completely

renewed every 16 days on average, and water in the

atmosphere is renewed every 8 days, but the renewal

periods of glaciers, groundwater, ocean water, and the

largest lakes run to hundreds or thousands of years.

These are, essentially, nonrenewable resources. When

people use or degrade these water supplies, useable

water resources are lost and natural water cycles may

be disrupted.

Water Quantity and the 

National Forests

Figure 2. Only a miniscule proportion of the Earth’s water is fresh

and available to humans and terrestrial and freshwater aquatic life,

making it a most precious resource. 

W

97.5%

Oceans & Seas

1.73%

Glaciers & Icecaps 0.77%

Total 

Fresh Water 

0.0008%

Available &

Renewable

Fresh

Water
2

THE QUANTITY OF WATER

FROM FORESTED LANDS

Forest Service literature from the 1940’s to the present (Gillian and Brown 1998) has asserted that 50 to

70 percent of the Nation’s runoff derives from national forest lands. But that assertion is only an often

repeated estimate, without a clear empirical basis.

More accurate knowledge of how much water comes

off national forest lands, where it flows, and how it is

used is essential for understanding what waters forest

managers are managing, their economic values, and

the options for their future use.

In order to answer the fundamental questions

about yield and value of waters flowing from the

national forests, we estimated runoff using a sophisticated, spatially explicit simulation model. The model

found that water yields from national forests are less

than 20 perent of the total surface runoff from the

contiguous 48 States (see figure 3). This is significantly below the estimates of water yield found in earlier

Forest Service literature.

Water runoff from forested areas, including national forests, was derived using the Mapped Atmosphere

Plant-Soil-System (MAPSS) model (Neilson 1995).

The MAPSS model simulates the distribution of

forests, savannas, grasslands, and deserts with reasonable accuracy. It is more accurate for forested than

nonforested areas, and confidence is lower in the

topographically complex and arid Western States. The

model produced annual estimates of runoff per 100-

square-kilometer grid cell in the continental United

States. Forested areas, national forest lands, and

watershed boundaries were overlaid on this grid to

estimate runoff. In addition, runoff was estimated for

the national forests in each of the 18 water-resource

regions in the contiguous 48 States. 

The model accurately reproduces observed monthly runoff. At the continental and hydrographic-region

scales, the model performs well compared to

published maps and U.S. Geological Survey data on

measured runoff. 

About two-thirds of the Nation’s runoff, excluding

Alaska, comes from forested areas. National forest

lands, which represent 8 percent of the contiguous

U.S. land area, contribute 14 percent of the runoff.

National forest lands are the largest single source of

water in the United States. National forests yield

water of unusually high quality. This high quality

water and its associated watersheds anchor native

fishes, mussels, and amphibians. Forested watersheds

east of the Mississippi River generally receive more

rainfall and produce more surface water per unit area

than forested lands to the west. They also tend to have

a more even distribution of runoff during the year.

Their floods are usually caused by hurricanes or tropical storms, unlike western watersheds in the snow

zone where spring snowmelt, sometimes supplemented by rainfall, causes the annual peak flows. Low flows

in the East usually occur during dry summers when

evapotranspiration rates are greatest; in the western

mountains, annual low flows usually occur in midwinter. More than 60 percent of the Nation’s runoff is

from east of the Mississippi River, where 70 percent of

the Nation’s private and State forests are located.

National forests in the East are responsible for 6 percent of this runoff (see the lower graph in figure 3).

We estimated the actual runoff from national forest

lands for the 18 water resource regions of the

Figure 3. Proportion of runoff from all forested lands and national forest

of the continental United States (upper graph), derived from Neilson,

1995. Proportion of runoff from all forested lands and national forest

lands east and west of the Mississippi River (lower graph). 

Water Quantity and the 

National Forests

National Forest Lands All U.S Forested Lands Total U.S

National 

Forest 

Lands

Eastern U.S. Western U.S.

Forested

Runoff

Total

Runoff

National 

Forest 

Lands

Forested

Runoff

Total

Runoff

1800

1600

1400

1200

1000

800

600

400

200

0

1300

1200

1100

1000

900

800

700

600

500

400

300

200

100

0

Millions of acre-feet per year 109

m3/year

Source of our Nation’s Waterways
3

contiguous United States (see figures 4 and 5). The

greatest yield of water from national forest lands is

from the Pacific Northwest (Columbia River plus

coastal and Puget Sound rivers) and California. These

regions have more than 20 percent of their area in

national forest lands. The Tennessee River basin has

about 6 percent national forest lands, but these are the

wettest parts of the basin and yield much more water

than their land area would suggest. Although water

from national forest land contributes only 6 percent of

the Missouri River, it is most of the water from

Wyoming, Montana, and Colorado. Nearly half of the

water from the Upper Colorado basin flows from

national forest lands, yet it yields only about half the

water a smaller area of national forest land produces

in the Ohio River basin.

Figure 4. Water resources regions of the United States (Source U.S. Geologic

Survey). 1 New England; 2 Mid-Atlantic; 3 South Atlantic-Gulf; 4 Great

Lakes; 5 Ohio; 6 Tennessee; 7 Upper Mississippi; 8 Lower Mississippi; 9

Soiris-Red-Rainy; 10 Missouri; 11 Arkansas-White-Red; 12 Texas-Gulf; 13

Rio Grande; 14 Upper Colorado; 15 Lower Colorado; 16 Great Basin; 17

Pacific Northwest; 18 California; 19 Alaska; 20 Hawaii; 21 Puerto Rico.

Water Resources Regions of the United States

10

11

12

13

19

20

21

18

17

16

15

14

07

08

09

04

02

05

06

03

01

Puerto

Hawaii Rico

Alaska

Figure 5. The contribution and proportion of water runoff from national

forest lands to the 18 water resource regions of the contiguous United

States. Runoff estimate was derived using the MAPPS model (Neilsen

1995). The bars represent yearly water yields from national forest lands.

Percentages are the proportion of the total runoff from the water resource

region that flows from national forest lands.

8%

6%

7%

5%

46%

38%

32%

38%

45%

4% 4%

6%

9%

7% 23%

2% 29% 5%

Runoff from National Forest Lands

%=proportion of the

water resource regions

runoff that comes from

National Forest Lands

Soiris-Red-Rainy

Missouri

Arkansas-White-Red

Texas Gulf

Rio Grande

Upper Colorado

Lower Colorado

Great Basin

Pacific Northwest

California

New England

Mid-Atlantic

South Atlantic Gulf

Great Lakes

Ohio

Tennessee

Upper Mississippi

Lower Mississippi

90

80

70

60

50

40

30

20

10

0

Billion cubic meters/year

Water Quantity and the 

National Forests
4

National forests in the West provide proportionally

more water (33 percent) because they include the

major mountain ranges and the headwaters of the

principal rivers. For example, in California, national

forest lands occupy 20 percent of the State but produce nearly 50 percent of the State’s runoff. The

Pacific Northwest shows the same pattern. 

The agency is using basins and watersheds in the

latest rounds of forest plan revisions, regional environmental impact statements, and assessments.

Because of higher rainfall in the East, the smaller and

more fragmented national forest lands in the Eastern

and Southern Regions generate large volumes of

runoff compared to the contiguous mountain forests

in the Rocky Mountain, Southwest, and Intermountain Regions (see figures 6 and 7). The runoff from

the regions provided the basis for calculating the

marginal value of water discussed in the next section. 

Figure 6. The Forest Service has eight administrative regions in the continental United States. The boundaries do not match up well to watersheds

or water resource regions.

USDA-Forest Service Regions

Northern

Inter-Mountain

Pacific

Southwest

Southwest

Pacific

Northwest

Southern

R Eastern ocky

Mountain

Puerto

Hawaii Rico

Alaska

USDA-FS Lands

Water Quantity and the 

National Forests

Northern

Region

National Forest System Streamflow

(million acre-feet)

Rocky Mountain

Southwestern

Intermountain

Pacific Southwest

Pacific Northwest

Southern

Eastern

0 10 20 30 40 50

Figure 7. Stream flows from national forest lands for each region. Because

of the greater rainfall in the Eastern and Southern United States, more

streamflow per unit area comes from these national forests. 
5

Comparing water supplies to current withdrawals

indicates the likelihood that a small change in flow

would affect off-stream uses. If only a small proportion of available flow is diverted, off-stream users are

unlikely to be affected by a small change in flow,

except perhaps in a very dry year. This comparison

was performed for the 18 water-resource regions of the

contiguous 48 States, with the exception that the

upper and lower Colorado regions were combined

because so much of the lower basin’s supply originates

in the upper basin. The proportion of water supply in

each region withdrawn for off-stream use is shown in

figure 8. In general, off-stream users in regions with

ratios below about 0.2 are not likely to be affected by a

marginal change in flow. But these regions are large

and areas of shortage may exist even in regions with

very low total ratios of withdrawal to supply.

Even though the MAPSS model is biased toward

underestimating runoff, water yields from national

forests are much lower than the estimates that appear

in the reports of the Chief dating back to 1947. The

figures reported here are more accurate but not precise enough to use on a forest-by-forest basis. Additional work is needed to refine the estimates to the

national forest scale. 

DETERMINING A WATER VALUE FOR THE

NATIONAL FOREST SYSTEM

The economic importance of water can be characterized in two ways, by estimating its economic effects in

terms of jobs or income, and by estimating what the

public is willing to pay for it. Willingness to pay, the

value addressed here, can exist for anything of

value—a market good like bottled water, a nonmarket

good like a recreational fishing experience, or a socalled “nonuse” service like the knowledge that a certain riparian habitat is well cared for. Measuring these

values is anything but straightforward, and most estimates are only approximate.

Most economic valuation studies of water have

focused on the marginal value of water volumes available for instream and offstream uses. The estimated

marginal values reflect our willingness to pay for a

change in the amount of water, and they are of interest because management actions typically cause only

small changes. In some water-short areas, water markets have emerged that also provide indications of

marginal values. Evidence from these two sources

suggests that (Brown 1999):

■ Economic studies of water value tend to be

performed, and water markets tend to develop,

where water is scarce. The values determined in such

studies or markets are likely to overestimate values

for water supplies where water is not so scarce.

■ Marginal values of streamflow in any one use

depend on the degree of water scarcity, which in

turn depends on localized water demand and supply factors, including the capacities of water facilities like reservoirs and canals. Degree of scarcity is

highly site-specific, which makes transferring values reliably from one site to another difficult.

■ The marginal value of streamflow depends on the

variety of uses to which the flow may be put. Its

value for instream uses—producing electricity at

hydroelectric plants or providing for habitat, recreation, and waste dilution—must be added to values

in off-stream uses. Most diversions to off-stream

uses consume some water but also provide some

return flows that can be used by others

downstream.

■ The marginal value of streamflow in off-stream

uses can be zero in locations with ample water

supplies. Depending on recreation demand and

hydroelectric plant capacities, the marginal value

of water in instream uses may be positive even in

water-rich areas.

■ Although values vary widely from one site to another, for typical areas without ample water supply,

Figure 8. The proportion of water supply that is withdrawn to off-stream

use in the 18 water-resource regions of the United States. If only a small

proportion of available flow is diverted off-stream, off-stream users are

unlikely to be affected by a small change in flow, except perhaps in very

dry years. (Alaska and Hawaii not included)

California

Pacific Northest

Great Basin

Upper Colorado

Lower Colorado

Rio Grande

Texas-Gulf

Arkansas-White-Red

Missouri

Souris-Red-Rainy

Lower Mississippi

Upper Mississippi

Tennessee

Ohio

Great Lakes

Mid-Atlantic

New England

Systems with a ratio

above 0.2 are likely to

be affected by a marginal

change in flow

Ratio of water withdrawal to supply

0 0.2 0.4 0.6 0.8 1

Water Quantity and the 

National Forests
6

economic studies and transaction evidence suggest

a marginal value of streamflow delivered to offstream uses of roughly $40 per acre-foot, on average. A few economic studies report higher values

than this for municipal and industrial water, but

the evidence is too limited to be applied to broad

areas in large-scale assessments such as this one.

■ Marginal values of water in producing electricity at

hydroelectric plants range as high as $40 per acrefoot for flow originating at the headwaters of one

highly developed watershed, but the values are

much lower for most places. Average values per

acre-foot of flow in each of the 18 water-resource

regions (U.S. Water Resources Council 1978) of the

contiguous 48 States are conservatively estimated

to range from $0.26 to $17.00, with most below $2.

■ Marginal values of streamflow for recreation differ

widely from one site or season to another, depending on a host of factors, but evidence from

economic studies suggests that the marginal value

of streamflow for recreation is below $10 per acrefoot in most places.

■ The total value of streamflow from national forests

depends on the average value over the entire

amount of use, not on the marginal value. Because

average values may greatly exceed marginal values,

the average value of streamflow from national

forests may be high even where the marginal value

is modest, especially in watersheds where national

forests contribute a substantial portion of the total

water supply. Average values are not observed in

the market place and are difficult to measure;

therefore, estimating the total value of streamflow

is difficult. Nevertheless, with appropriate assumptions and the use of marginal values as a lower

bound on average values, a rough estimate of total

value may be obtained. 

■ The estimates of runoff from the national forests

were adjusted to correct for discrepancies between

the total land area within the mapped boundaries of

the national forests and the area the Forest Service

actually manages. As expected, the difference is

greatest in Regions 8 and 9, where the Federal

holdings are more fragmented. This correction

removed the difference between the “gross acreage”

and the “National Forest System acreage” (USDA

Forest Service 1997). The volume of runoff from

the national forests as estimated by the MAPSS

model, corrected to reflect the actual land area

under Forest Service management, is the national

forest instream flow shown in column 2 of table 1.

Not all water is diverted for off-stream use and

much water flows directly to the ocean without passing through irrigation canals, municipal diversions,

or the like. Therefore, the numbers for water flowing

from units of the National Forest System were corrected to include only the water actually used

offstream. Data on water withdrawals were taken from

the U.S. Geological Survey (Solley et al. 1998). The

percentage of total runoff in each region attributable

to national forest lands was divided by the total runoff

from all lands in the corresponding Forest Service

region, as determined by the MAPSS model. The

resulting fraction was multiplied by the total runoff in

each Forest Service region that goes to offstream uses

based on the U.S. Geological Survey data. The results

are shown in column 3 of table 1. 

The lower bound on the value of runoff from Forest Service lands was estimated by applying the average marginal values discussed above (Brown 1999) to

the estimates of water yield shown in table 1 for each

Forest Service region. Withdrawals to offstream uses

were valued at $40 per acre-foot, and instream flow

was valued at $17 per acre-foot in the West and $8 per

acre-foot in the East for recreation and hydropower

combined. Dilution, navigation, and nonuse values

were assumed to be nil. The results of these calculations are shown by Forest Service region in figure 9.

The value of water flowing from national forests, in

both offstream and instream uses, is conservatively

estimated to be at least $3.7 billion per year. 

This estimate makes it possible to compare the

total value of the water originating on the national

forests with similar values for other forest resources.

It provides a general idea of the relative importance to

Table 1. Water Supply from National Forests by Forest Service Region

Sources: Derived from Solley et al. (1998) and Neilson (1995)

National Forest National Forest 

Region Instream Flow Offstream Use

Acre-feet Acre-feet

Northern 15,914,000 3,815,342

Rocky Mountain 9,144,792 2,150,811

Southwestern 7,428,051 1,971,245

Intermountain 11,458,855 4,785,689

Pacific Southwest 33,201,475 9,496,005

Pacific Northwest 44,658,346 4,806,316

Southern 19,041,809 3,587,515

Eastern 14,714,248 3,376,458

Water Quantity and the 

National Forests
7

society of the various resources and equips the public

to make informed decisions about alternative uses of

their forests. 

Water runoff is different from many other

resources, in terms of the degree of Federal ownership and control. Although the agency generally has

legal authority to decide about the sale or use of timber stumpage, livestock grazing, and recreation

access, the Federal Government has not established a

legal right to most of the water flowing from the

forests. Hard-rock minerals and fish and wildlife present a contrasting case, more like that of water runoff.

Locatable minerals are owned by the Federal Government, but the agency does not control access. Fish

and wildlife are owned by the State, with access controlled by the agency and “take” controlled by the

State. In both cases, although the resources are not

owned by the Federal Government, they do have value

to society, and in both cases the Forest Service estimates and reports on those values. 

TRUE VALUE OF WATER

IS UNDERESTIMATED

This estimate of of value understates the true value of

water flowing from the national forests in three ways.

First, our analysis counts marginal value rather than

average value, even though average values may greatly exceed marginal values. Second, our estimates

ignore values attached to navigation, waste dilution,

channel maintenance, and such ecological services as

aquatic habitats and wetland functions. Third, our

analysis does not count nonuse values—existence

value, option value, and bequest value—even though

some studies indicate that nonuse values may be substantial. The values estimated through this analysis

thus represent a lower limit on the range of values

attributable to waters flowing from the national

forests. The actual values of these flows are almost

certainly higher, but how much higher is not known.

Providing cold, clear waters of high quality for

aquatic organisms and human use is probably the

proper focus for managing water on the National Forest System. There is relatively little management can

do to increase total water yield. But forest management

can have major effects on water quality—affecting temperature, nutrient loadings, sediment yields, and toxic

contaminants. Management can also affect the storage

capacity of soils and alluvial deposits, marginally affecting magnitude of peak streamflow and the duration of

dry-season streamflows. 

Water quality changes affect aquatic habitats,

downstream water management facilities, recreation

opportunities, and water treatment costs. Land management can cause increases in flood peaks and

reduced channel stability, and impact the ability of

downstream water users to benefit from the streamflow. The values of changes in the quality or timing of

streamflows have received less attention by

economists than has total quantity, partly because

quality and timing are more difficult to monitor. The

economic value of careful forest management—management that protects soils and water quality and

takes full advantage of the watershed’s ability to temporarily store water and ameliorate downstream flood

damage—calls for additional study, but it is not

addressed in detail in this paper. The economic analysis in this paper provides only a first approximation of

the minimum value to society of the waters flowing

from the national forests. Other measures of value

attributable to national forest waters remain to be

filled in by further studies

MANY COMMUNITIES DEPEND ON

WATER FROM THE NATIONAL FORESTS

In 1999, the Environmental Protection Agency (EPA)

estimated that 3,400 public drinking-water systems

are located in watersheds containing national forest

lands. About 60 million people live in these 3,400

communities. We will eventually have a more accurate

picture of the role of the forests in providing municiFigure 9. Annual value of water from national forests by region. The marginal value of water from all national forest lands is at least $3.7 billion

per year. 

Northern

Region

Marginal Value of Water from National Forests Lands

(millions of dollars)

Rocky Mountain

Southwestern

Intermountain

Pacific Southwest

Pacific Northwest

Southern

Eastern

0 200 400 600 800 1000

Water Quantity and the 

National Forests
8

pal water supplies. All 50 States and many participating tribes are now delineating the surface watersheds

and groundwater recharge areas that provide public

drinking water to the 68,000 communities that rely on

surface water or groundwater for their public water

supplies. This effort will extend over the next 4 years,

as required by the Safe Drinking Water Act. 

In most of the West, a relatively few public water

systems and watersheds supply most of the population. For example, in Washington State, 86 percent of

the population is served by a few very large public

water systems, nearly all of which draw from national

forest lands. However, the 69 percent of public water

systems that serve less than 100 connections (see figure 10) could also be of major concern to the Forest

Service, because of the large number of such systems

and the passion with which people pursue protection

of their water supplies. 

An update of the 1978 inventory by Region 6

showed that the number of communities in Oregon

obtaining drinking water from National Forest System watersheds in 1998 was more than 50 percent

higher than in 1978. Water from national forest lands

supply about 80 percent of Oregon’s population of 2.8

million people. 

The Siuslaw National Forest in Region 6 has identified 136 public water systems on national forest

lands encompassing 36 percent of the forest. Municipal water supply watersheds encompass 85 percent of

the Rogue River National Forest and 94 percent of the

Umpqua National Forest. 

In the Northern United States (21 States), 76.5

million people are served by water from nearly 4,000

surface water systems. National forest lands contain

925 water systems serving about 7.75 million people.

In Massachusetts, 11 percent of the area of the State

serves the water needs of nearly 7 million people. The

municipal watersheds there are more than 72 percent

forested. New York City’s municipal watershed is

more than 60 percent actively managed forest. 

California’s State Water Project, with 22 dams and

600 miles of canals, delivers water that originates

largely on national forest lands in the Sierra

Nevada—more than 2 million acre-feet annually—to

20 million urban and agricultural users in both the

San Francisco Bay and southern California. The Federal Central Valley Project includes another 20 reservoirs and more than 500 miles of canals that deliver

another 7 million acre-feet to irrigate 3 million acres

in the Central Valley and provide drinking water to 2

million urbanites.

More than 900 cities rely on National Forest System watersheds, including: Portland, Salem, Eugene,

and Medford, OR; Eureka, Oakland, and Berkeley, CA;

Denver, Fort Collins, and Colorado Springs, CO; HeleFigure 10. Washington’s community water systems. A relatively small number of water systems supply large numbers of people. Numerous water systems serve small numbers of people each, but each of them that includes

National Forest could be an important issue for the Forest Service.

Water Quantity and the 

National Forests

69%

8%

23%

10% 86%

4%

>1000 Connections

197 Systems

4,133,286 pop.

>100 to <1000

Connections

544 Systems

483,893 pop.

<100 Connections

1,591 Systems

175,503 pop.

By Number of Systems By Population Served

Washington State Community Public Water Systems
9

na, Butte, and Bozeman, MT; Salt Lake City, UT; Reno,

and Carson City, NV; Little Rock, AR; and Ely, MN.

Relatively more western than eastern cities use

national forest water because of the relatively larger

land base in the Western States.

Should municipal watersheds be managed under

an active or a passive regime? Many Forest Service

specialists believe that long-term supplies of highquality water can best be sustained under an active

program of vegetation management designed to

maintain the forest system and watershed processes

within their natural range of variability. Many people

in urban centers believe that humans should not alter

watersheds in any way, other than to divert water. The

scientific evidence indicates that watersheds can be

effectively managed for high-quality water while providing for other resource outputs as byproducts. ❖

Water Quantity and the 

National Forests
10

TREAMFLOW REGIMES, 

TIMING, AND FLOODS

The experience of widespread flooding

and sedimentation following on the

heels of logging and fire was one of the primary reasons for establishing national forests. The timing of

water yields was also an important issue, especially

the desire to augment late-season flows. Extending

the irrigation season and limiting the adverse effects

of drought were also significant concerns.

A wide range of human activities, including forest

management, roads, reservoir and dam operation, loss

of wetlands, development and urbanization of floodplains and other flood-prone areas, and stream channelizing have been implicated as factors increasing

the destructive potential of floods. 

A wide range of agencies is responsible for various

aspects of flood prediction and control, but no one

agency or group of agencies is charged with evaluating the consequences of its actions in relationship to

other parties. Although forest practices may increase

peak flows and sediment transport from upland

streams, downstream effects may be minimized where

reservoir operation reduces flood peaks and sediment

accumulates in reservoirs. On the other hand,

sustained high-flow releases from dams may

contribute to higher sediment and turbidity problems

downstream compared to shorter but higher natural

peak flows. 

In the Intermountain and Southwest Regions, the

relationship between healthy vegetation groundcover

and reduction of summer floods from high-intensity

storms has been well established, as summarized by

Coleman (1953)(see figure 11). 

The change in runoff associated with different

degrees of ground cover shows that watershed cover

and on-site water control measures can reduce flood

threats. Similar reductions in flood peaks have been

observed in the East after watershed restoration. For

more humid areas, the effect of vegetation management and healthy upland watershed conditions is still

important in limiting erosion and sedimentation

effects from floods.

Substantial and dependable beneficial shifts in timing of peak runoff are unlikely to be achieved through

managing forest vegetation and snow. In the Eastern

United States and to some degree in the West, harvest

Water Quantity Issues 

for Forest Planning

Figure 11. Experimental results of the effects of watershed condition on

rainstorm runoff and erosion (data from Great Basin Experimental Area, UT). 

S

GOOD Ground Cover

60-75% of ground covered 

with plants and litter

Surface 

Runoff

2% of rainfall

Soil Loss

0.05 Tons 

per acre

Surface 

Runoff

14% of rainfall

Soil Loss

0.5 Tons 

per acre

Surface 

Runoff

73% of rainfall

Soil Loss

5.55 Tons 

per acre

FAIR Ground Cover

37% of ground covered 

with plants and litter

POOR Ground Cover

10% of ground covered 

with plants and litter
11

activities have increased late-season flows. These

changes are typically short lived, however, because of

vegetation regrowth. Sustaining late-season flows is

an important issue and limited scientific studies have

focused on the relation between healthy watershed

conditions and sustaining late-summer flows. Anecdotal observations from a variety of watershed and channel restoration projects suggest that perennial flows

have often been restored to apparently ephemeral

channels by managing and restoring vegetation. Many

watersheds and meadows have been incised as a result

of poorly located travelways and roads. Other areas

have greatly expanded channel networks as a result of

excessive livestock use that produced gullys and

incised channels. The effect of these slope, meadow,

and channel incisions is to drain local groundwater

storage and transmit flows downstream more rapidly.

This process leaves little effective ground storage to

sustain late-season flows or to carry over water storage into a drought year. Preventing incisions and

restoring incised slopes, meadows, and streams could

improve late-season flows (see figure 12). Improving

these conditions should be a focus of watershed

restoration efforts. Concurrently, additional research

is needed to understand the process and

consequences of incision and the values obtained in

late season flows through restoration activities. Roads

and their effects on draining slopes and increasing

channel density need additional study as well.

In summary, limited but valuable opportunities

through forest management could shift the timing of

flows. A vital aspect is to prevent or limit incisions in

slopes, meadows, and channels. Treatments that

restore these areas and thus restore the relation of

channels to the floodplains and increase the contact

time of runoff on slopes and meadows are likely to

recharge soil profiles and shallow ground water reservoirs, which would greatly increase the likelihood of

sustaining late-season flows.

AUGMENTING STREAMFLOW

Producing substantial and extensive increases in

water yields from the national forests does not appear

to be practical. Research has demonstrated that water

yields can be increased by removing vegetation and

trapping additional snow. But application of the vegetation management practices needed to increase flows

on a watershed scale is limited in practice by Forest

Service mandates to manage for a wide range of

resource values. Legal constraints, land allocations,

technological limits, as well as societal values and

environmental, ecological, and biological concerns all

favor not committing national forest lands to the

management regimes that would be needed to

increase water yields. 

Ziemer (1987) offers one of the best summaries

and evaluations of the potentials and limitations of

augmenting water yield on forested lands in the United States. His findings indicated that for a variety of

reasons, water yield increases are likely to be undetectable. Forest research has demonstrated that cutting trees, type converting of brush to grass, and

snow management can produce increased water

yields. These increases generally come from lands that

receive more than 15 inches of annual precipitation.

In general, areas with higher precipitation, typified by

mixed conifer species; spruce, fir, and lodgepole pine

forests; and eastern hardwoods produce more yield

per unit area than other forest types.

Although water-yield increases can result from forest management activities, the increases produced by

normal silvicultural methods applied in the context of

multiple use are modest. Even in wet environments of

the Northwest (Harr 1983) and the Sierra Nevada of

California (Kattelmann and others 1983) these

Figure 12. Comparative rainfall and storm runoff hydrographs, White

Hollow, TN, before and after watershed rehabilitation. 

3000

2000

1000

0

50

25

0

25

0

2 4 6 8 10 12 14 16 18 20

July 1938 surface runoff

Discharge (Ls-1) Rainfall, (mm h-1)

August 1945 surface runoff

July 1938 storm rainfall, =29 mm

August 1945 storm rainfall, =25 mm

Water Quantity Issues 

for Forest Planning
12

increases could be in the range of 6 percent, if water

yield were strongly emphasized, but more likely 1 percent under normal management. Detecting and measuring this small change is outside the limits of

current technology (Ziemer 1987). The most productive areas for this potential would have the shortest

duration because of rapid regrowth of vegetation

reoccupying the site.

Properly evaluating augmentation potential often

overlooks the legacy of historical forest management

actions. Frequently, much of the potential for

augmentation is already being realized. For example,

in the Southwest, Schmidt and Solomon (1981) estimated that about 50 percent of the potential was

already being realized. 

Strategies for dealing with water shortages should

avoid relying on augmentation from national forests

as a substitute for practices to reduce water consumption and improve conservation.

INSTREAM FLOW REQUIREMENTS

Sustaining viable native populations of aquatic species

on national forest lands will require securing instream

flows that fall within the range of natural variation.

Natural streamflows exhibit complex regimes, with

important and life-sustaining variations in their frequency, magnitude, duration, and timing. Fish and

other aquatic and riparian organisms depend directly

on this regime and the habitats that it forms and

maintains. Some departure from these regimes is tolerable and will not extirpate organisms, but this

threshold is difficult to define. The Forest Service

must actively participate in the processes that allocate

water and water rights to secure instream flows sufficient to sustain native populations.

Policy Implications

Forest plans should be integrated with watershed

assessments (assessments are conducted on all lands

within a watershed not just national forest lands) and

with watershed recovery plans so that goals are clear

and of sufficient scope to include watershed management and restoration opportunities across

ownerships. See figure 13 for examples of past and

future strategies to obtain instream flows.

Greater involvement of partners and other members of the public in the planning process would likely

need a better understanding of the need to integrate

management opportunities on all lands within a

watershed including private lands.

Forest plans, when they are revised, should identify

and quantify the amounts of surface and groundwater

needed to meet present and future consumptive and

instream water uses on national forest lands. When a

State undertakes a basinwide adjudication of water

rights, all beneficial water uses on national forest

lands should be claimed in accordance with Federal

and State procedural and substantive laws and regulations, unless otherwise directed by the Office of the

General Counsel. Forest planning should use the

most defensible methods and avoid inconsistent and

piecemeal analyses. 

Early and intensive collaboration among existing and

potential water users is a cost-efficient approach in most

situations. Public collaboration in forest planning can

achieve acceptable solutions and may lessen or avoid the

costly litigation common to water rights issues. 

In many places, the Forest Service lacks the necessary technical expertise in hydrology. Our present

level of in-house expertise must be conserved and

Figures 13. Past strategies have been to litigate to secure favorable flows

and protect the public interest. In the future, the agency will incorporate

flows needed to meet multiple-use mandates through forest planning, as

well as by litigation and negotiation. 

Litigation

Litigation

Past Strategies for Obtaining Instream Flows

Future Strategies for Obtaining Instream Flows

Forest Plan

Forest Plan

Cost: $5 million/yr

In: 39 basins, 8 States

43,000 claims pending 

State courts control timing,

duration, costs, claims

Low to High rates of success

Cost: $200K-$500K/forest

Just a few forests have done

Outside State court system

High chance of success in 

East, Midwest U.S.

Cost range $200K-$500K

per forest

Needs to be done for all forests

Better public involvement,

support

Variable rates of success

Expected lower costs

Fewer claims to be

defended

Variable rates of success

more balanced

policy strategy

adjudication projects

adjudication projects

Water Quantity Issues 

for Forest Planning
13

Puerto

Hawaii Rico

Alaska

USDA-FS Lands

Hydropower dams:

on USDA-FS Lands

outside USDA-FS Lands

●

●● ●

●

●● ●●

●●

●●

●

●●

●●

●

●

●

●

●

● ●

●

●

●

●

● ●

●

●

●

●

●

●●

●

●

●

●

●● ●●● ● ●●●

●●●●

●

●●

●●●

●

●●

●●●

●

●●

●●

● ●

●

●● ● ●●

●

● ●

●

●

●

● ●● ● ●●●●

●

●

● ●● ●●

●● ●●●●

●

●

●

●

●

●

●●

●

●

●

●

●●

●●

●

●

●●●

●

●

●

●

●

●●

●

● ●

●

●

●

●

●

● ● ●

● ● ●

●●

●

● ● ●

●

●

●

●●

●●

●

●

●●

●

●● ●● ●

●

●

●

●●

●

●●

●●●

●

●

●●●

●●●

●

●

●

●

●● ●●●● ●

● ●

●

●●●●

●●●

●

●●●

●●

● ●

●

●●

●●

● ●

●

●

●

●

●

●

●

● ●

● ●● ●

●●●

● ●

●

●

●

●

●

●

●

●

●

●● ●

●●

●●

●

●●●

●●

●

●●●

● ●

●●

●● ●

●

●

●

●

● ●

● ●

● ● ●

●

● ●

● ●

●

●

●●●●●

●

●

●

●

●

●

●

●

●

●

●

●

● ●

●●

●

● ●

● ●●

●

●●●

● ● ●

●

● ●

●● ●●

● ● ●

●●● ●●● ● ●●●● ●

●●

●● ●

●● ● ● ●

● ●

● ●●●

●

●●●●

● ●

●● ●●

●

●

●

●●●

●●

●

●

●

●●● ●●

●● ●

● ●

●●

●●● ● ● ●●

●

● ●●

●

●●●● ●●●●●

●

●●

●● ●●

●

●

●

● ● ● ●

●●● ●

●●●

●

●●

● ●●

●

●●

●

● ●●●●

●●

●

●●●

● ●●

●

●●

●

●

●●●

●

●

●

● ●● ●

●

●

●

●

●●

●●● ● ●

●●

●●

● ●●

●● ●

●●

●

●

●

●

● ●●●

●●●

●●

●

●

● ● ●● ● ●● ●

● ● ● ●

●

●

●

●●● ●

●●

● ●

●

●●

●●

●

● ●

● ●

●

●

●●● ●●●

●

●●

●●

●●

●

●

● ● ● ●

●

●

●●

●

●

●

●

●

●● ●

●

●

● ●

●

●● ● ●●

●●●●

●

● ●●

●

●●● ● ● ● ●

●

●

●

●

● ●

●

● ●

●

●

●

●

●● ●

●

●●

●● ●

●

●

●

●

●●●

●

●●● ● ●

●

●

● ●

●

●

●● ●

● ●

●

● ● ●●●●

●●●

● ●

●

●●

●●●

●

●●●

●

●●

●

● ●

●●

●●●●●●

●

●

● ●

●

●

●

● ●●●●

●

●

●

●●●

●

● ● ●●●●

●●●

●

●

● ● ●●

●

●●

●●●●

● ●● ●●●● ● ●

●●

●●

●●

●●●●

●●●

●

● ●●●

● ●

●

●

●

●●●●

●

●

●

●●

●

●● ●

●●

●

●

●

●

● ●

●

●●●● ● ●●●●

●

● ●

●

● ●

●

●

●

●

●●● ●●●

●

●●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

● ●●

●

●

●

●

●● ●●

●

● ●

●

●●

●●●

●

●●● ● ● ●●

●

●●

●●

●●

●

●

● ●

●

●

●

Figure 14. Hydroelectric dams in the 48 States both on and off national

forest lands. The largest number of small hydroelectric dams is in the New

England, Great Lakes, southern Appalachian, and Mid-Atlantic areas. 

Table 2. Hydroelectric dams licensed by the FERC in each Forests Service

region, both on and off national forests lands. Data derived from the National

Inventory of Dams maintained by the U.S. Army Corps of Engineers, compiled and developed by the Pacific Northwest Research Station.

Forest Service Region Number on Number off

NFS land NFS land Total

Northern (R1) 9 21 30

Rocky Mountain (R2) 21 71 92

Southwest (R3) 3 3 6

Intermountain (R4) 10 34 44

Pacific Southwest (R5) 152 87 239

Pacific Northwest (R6) 35 74 109

Southern (R8) 49 246 295

Eastern (R9) 31 1,318 1,349

Alaska (R10) 15 15 30

Total 325 1,869 2,194

Water Quantity Issues 

for Forest Planning

enhanced if costly failures, both in collaboration and

in court, are to be avoided. 

FERC RELICENSING

From the 1940’s to the 1960’s, 325 hydroelectric projects were licensed and built on the national forests

(see table 2). These facilities have generated power

and provided recreation opportunities. But building

and operating these projects has also resulted in significant adverse effects on national forest resources.

During the next 10 years, as more than 180 of these

projects come up for relicensing, the Forest Service

will have a unique opportunity to determine how

these projects will operate for the next 30 to 50 years.

The relicensing process presents the only chance for

the Forest Service to reverse existing resource damage, improve water quality and aquatic habitat, mitigate future adverse effects, and significantly increase

recreational opportunities to forest users.

The national distribution of dams provides an

interesting look at how these dams are spread across

national forest lands (see figures 14 and 15). 
14

There are nearly 2,200 hydroelectric dams in the

United States, excluding Hawaii and Puerto Rico;

about 15 percent of these are on national forest lands.

Forest Service strategies for dealing with relicensing

may differ among the regions because the issues and

complexity vary with factors such as dam size, the

river basin and biological contexts, interbasin water

transfers, and cumulative effects. 

The large-scale hydrologic effects of American

dams have recently been assessed by Graf (1999). Graf

found that the greatest density of dams and the greatest segmentation of river systems in California, the

Texas-Gulf, and South Atlantic water resource regions

(see figures 14 and 15). Regions with high ratios of

storage capacity to drainage area show the highest

potential for changes to instream flows and ecological

disruption. The greatest flow effects are in some western mountain and plain regions, where dams can

store more than 3 years of runoff. The least effects to

flow are in the Northeast, Upper Midwest, and Northwest where storage is as little as 25 percent of the

annual runoff. 

The regional variability of impacts and numbers of

dams suggests that the Forest Service cannot tackle

every dam relicensing on national forests with the

same intensity. Nationally and regionally, we must

focus strategically on the basins and dams where we

can expect to achieve the greatest benefits for biodiversity, recreation, and ecosystem function in large,

complex, mixed-ownership watersheds.

The Forest Service has binding statutory authority

and responsibility from the Federal Power Act (FPA)

to stipulate license conditions the Federal Energy

Regulatory Commission (FERC) must include in the

new license. To successfully condition these licenses,

the Forest Service must develop a substantial and

defensible administrative record to support the articles that have been “demonstrated necessary for the

adequate protection and utilization of national forest

resources.” Developing the administrative record

requires a significant commitment by the Forest SerFigure 15. Hydroelectric dams in the 48 States on national forest lands.

The largest number of these dams are on the west coast.

Puerto

Hawaii Rico

Alaska

●

●● ●

●

●● ●●

●●

●●

●

●●

●●

●

●

●

●

●

● ●

●

●

●

●

● ●

●

●

●

●

●

●●

●

●

●

●

●● ●●● ● ●●●

●●●●

●

●●

●●●

●

●●

●●●

●

●●

●●

● ●

●

●● ● ●●

●

● ●

●

●

●

● ●● ● ●●●●

●

●

● ●● ●●

●● ●●●●

●

●

●

●

●

●

●●

●

●

●

●

●●

●●

●

●

●●●

●

●

●

●

●

●●

●

● ●

USDA-FS Lands

Hydropower dams:

● on USDA-FS Lands

Water Quantity Issues 

for Forest Planning
15

vice in terms of technical and process personnel and

financial support. Relicensing processes normally take

5 to 10 years.

Forest Service participation in the relicensing

process could strengthen mitigation and restoration

programs on national forest lands that would lead to

improved aquatic habitats and increased water quality. Estimates of these benefits to national forest lands

exceed a billion dollars. Recreation, fish and wildlife,

and watershed resources are the primary areas affected by hydroelectric generation, and these resources

stand to realize the greatest benefits from the

relicensing efforts. Potential benefits include new

and upgraded recreational facilities, restored instream

flow regimes, enhanced aquatic habitats, and

improved wildlife habitat. Recent relicensing experiences have demonstrated that the benefit-to-cost ratio

can be greater than 30:1; no other Forest Service program has a higher potential payoff.

GROUNDWATER

The groundwater resource under the surface of

national forest lands has never been assessed at the

national, regional, or forest scales. The U.S. Geological Survey has compiled a national atlas of groundwater in the United States, and published detailed

regional studies of all major aquifers. Although neither of these sources show national forest lands, we

can infer some things from them about groundwater

in some parts of the national forest lands. We also

have access to well logs where wells have been drilled

on national forest lands by the agency or others. Many

forest acres serve as recharge areas for aquifers in

nearby valleys that many citizens depend on for their

drinking and irrigation water. We are unable to quantify the amount, timing, or quality of this recharge

with available data.

Over centuries, groundwater has been replenished

by inflows from rivers, lakes, and wetlands. At shallow

depths, the water table fluctuates with annual precipitation affecting lake levels and river flows. The value

of groundwater depends on the depth of the water

table due to drilling and pumping costs. We are not

aware of any studies that have quantified the economic values of groundwater functions.

The States vary in their regulation of underground

water. In many States, there is little if any regulation

or monitoring of the extraction of underground water

and there are unresolved jurisdictional questions over

who has control over water extraction within the

boundaries of the forests.

The ownership of groundwater is unresolved or

unaddressed in many States. For example, the State of

Virgina claims the water underlying Federal lands and

it remains unclear if such a claim has merit. 

Some existing special use permits involve the

extraction of groundwater on national forest lands, but

there is no agency policy on environmental effect

analysis, valuation, metering, or resale of this water. 

At least three groundwater-related issues affect

national forest lands: 

■ Some communities want to change from contaminated groundwater wells to surface water supplies,

and national forests are the logical or sole source. 

■ Groundwater extraction by adjacent communities or

landowners may be drying up nearby streams and

affecting riparian vegetation and aquatic habitat.

■ The status of groundwater ownership within the

national forests is unresolved in many States. The

Forest Service lacks the scientific expertise and

data on the groundwater resources underlying its

lands to effectively cope with these growing issues.

Policy Implications

The growth of urban interface adjacent to the National Forest System has exceeded the agency’s ability to

respond to the challenges of increased water demand.

Most current forest plans do not address water

resources in a comprehensive manner. Forests are

not adequately staffed with technical experts to handle the issues related to water that evolve faster than

they can be inventoried. Claims on water originating

from the National Forest System far outstrip the

agency’s ability to track them, much less manage the

issues.

Starting points for developing an effective approach

to the complex issues involved in water resources

management include: a comprehensive inventory of

State law, an analysis of conflicts with agency resource

management objectives, and a complete inventory of

Water Rights that are vested in the United States

(within the National Forest System). ❖

Water Quantity Issues 

for Forest Planning
16

orested watersheds have a well-deserved

reputation for producing clean water.

The Forest Service has conducted longterm research on the effects of land management on water quality at experimental

forests—such as Hubbard Brook in New Hampshire,

H. J. Andrews in Oregon, and Coweeta in North Carolina. Research shows that the quality of water in

undisturbed forests and grasslands is usually good. In

managed ecosystems, water quality depends on the

particular land-use practices being implemented.

Some land-use practices can protect or restore water

quality, but others may degrade or pose risks to clean

water. Long-term studies conducted by the Forest Service have provided much of the current understanding

of watershed processes in forests and grasslands, and

such studies will need to be continued to assess the

effects of forest management on water quality at landscape scales and over longer periods of time.

Most watersheds have several different land uses

that affect source waters in complex patterns. These

uses overlap across the landscape and change over

time. A few studies have examined the interactions

among multiple land uses and their cumulative

effects over time, but most have examined small

watersheds over short periods. More information is

needed to assist managers in dealing with the complexity of these interactions for larger watersheds and

longer time periods. 

A key action of the Clean Water Action Plan directs

the Departments of Agriculture and the Interior to

consult with other Federal agencies, States, tribes, and

other stakeholders to develop a Unified Federal Policy

to enhance watershed management for protecting

water quality and the health of aquatic ecosystems on

Federal lands. The purpose of the Unified Federal Policy is to ensure a consistent approach to managing Federal lands on a watershed basis, to protect, maintain,

and improve watershed conditions and water quality. 

In summary, forests and grasslands often produce

high-quality water. Long- term studies have shown

this to be generally true in undisturbed ecosystems

and for some classes of land use. Other forms of land

use have been found to degrade water quality to varying degrees. The most significant water quality problems found on national forests are typically sediment

(turbidity and bedload), nutrients, temperature, and

hazardous chemicals. Measures to protect, restore, or

mitigate water quality have been devised for many

management practices. New research will be needed

to understand the effects on water quality of innovative land management systems currently being

devised as part of ecosystem management and to

understand the cumulative effects of multiple management actions that overlap in space and time across

large landscapes. 

TOTAL MAXIMUM DAILY LOADS

Section 303(d) of the Clean Water Act requires that

total maximum daily loads (TMDL) be established by

States, tribes, U.S. territories, and EPA for waterbodies for which water quality standards are not being

attained. Such waterbodies are generally referred to as

“impaired” or “water quality limited.” Forest Service

policy is to participate in preparing and implementing

TMDL’s. The Forest Service is collaborating with the

EPA and Bureau of Land Management (BLM) to 

prepare a policy and framework for developing and

implementing TMDL’s in forest and rangeland 

environments.

TMDL’s for a pollutant is defined by the EPA as the

sum of the waste load allocation for point sources,

plus load allocation for nonpoint sources of pollution,

plus a load to allow a margin of safety (40 CFR 130.2).

The load allocation for nonpoint sources of pollution

includes “natural” background loads and the margin of

safety accounts for uncertainty. The TMDL approach is

a mechanism for improving impaired waters and a

process for determining tradeoffs between point and

nonpoint sources. It provides a focus for future watershed management actions.

A collaborative approach by all landowners in a

watershed is the potential strength of the TMDL

process. Its weaknesses are the current technical and

scientific barriers to connecting water-quality

standards to specific nonpoint sources, particularly

where the pollutants of concern are native components

of stream systems, like sediment and heat. Because of

highly variable natural background regimes and long

delays between the introduction of pollutants and

downstream effects, relating water quality standards to

the effectiveness of individual control measures is often

difficult or impossible. The lack of precision and reliability limits the utility of the TMDL process in allocating loads to specific management practices or to

individual landowners in forest and rangeland settings.

Creative approaches will be needed to salvage useful

gains from a legal framework that was designed for

point-source pollution control and fits nonpoint source

control poorly. The Forest Service should continue to

develop and monitor best management practices,

ensure a high rate of implementation, and revise those

Water Quality 

F
17

practices that are not effective, as the fundamental

basis of our water quality management program.

New technology developed by EPA and the Forest

Service for temperature monitoring uses forward-looking infrared radar to provide a spatially continuous

thermal profile over hundreds of miles of streams.

This technology is providing a framework for restoring

water quality and a picture of what sections are meeting and not meeting water-quality standards for temperature. This relatively cheap and accurate method is

an important tool in providing landscape context to

water-quality problems. 

ABANDONED MINE LANDS AND

HAZARDOUS MATERIALS SITES

At least 38,000 abandoned mine lands and hazardous

material waste sites exist on national forest lands.

These sites, most common on western forests, often

cause severe and chronic water pollution. In the early

1990’s EPA proposed that discharges from abandoned

mines be subject to permits under the Clean Water Act.

As an alternative, a “watershed approach” agreement

was made to coordinate the efforts of all land managers

and owners to efficiently and comprehensively address

restoration projects in entire watersheds, rather than

spot-treating individual sites. Key steps in the interagency agreement include setting priorities—among

watersheds in each State and mine sites within each

priority watershed—and monitoring. Several

watersheds were selected as pilots, including Boulder

River in Montana and Upper Animas River in Colorado.

Now included in the Clean Water Action Plan, cooperation and collaboration among States, Federal agencies,

and tribes is fundamental to the watershed approach.

This program is relatively new, and few mines have

been completely restored. ❖

Water Quality 
18

ational forest activities have affected

water quality and productivity of the land.

Problem watersheds and processes are

often masked by the size of the landscape,

or noticeable only when flooding or other disturbances

occur. Although most watersheds on national forests

appear healthy on a large scale, extensive localized

rehabilitation needs still exist on these lands. 

Concerns include soil degradation, lack of vegetative cover, eroding stream channels, gullies,

landslides, abandoned roads, and compacted rangeland. Some watersheds can be restored by emphasizing land management requirements and practices.

Some watersheds are so seriously affected that making a difference will be hard. Other watersheds are

expected to respond to intensive investment in erosion control features. Some types of work are intensive, structural, and expensive for a relatively small

site and need to be monitored and maintained. Biological treatments, like seeding, are extensive and

require little maintenance. 

Disturbances in forest and grassland vegetation

from drought, wind, fire, insects, and diseases are part

of properly functioning ecosystems in watersheds.

However, some past management practices—such as

fire exclusion, timber harvesting, and human development—have created watersheds that experience more

frequent or intense fire disturbances than in the past.

Many of these forests and grasslands are overcrowded

with increased susceptibility to drought, and insect

and disease outbreaks. The excessive amounts of dead

wood and grass, especially in watersheds that historically burned at frequent intervals, heighten the risk of

high-intensity, destructive fires. Large-scale vegetative

disturbances in a watershed adversely affect waterbodies by increasing soil erosion and nutrient runoff.

With dense stands of vegetation and large amounts of

dead fuel on the ground, the size and intensity of fires

can increase significantly and be accompanied by

greater risks of erosion, severity of floods, and

decreases in water quality. 

The long-term view is that healthy watersheds can

only be achieved if the ecosystems on the watershed

are healthy. Watershed restoration includes recovery

of natural timber and grass stands and fuels composition. Thinning, prescribed burning, and other management projects are needed on a watershed

(landscape) scale to significantly alter the predicted

course of events leading toward large-scale erosion,

flooding, and nutrient loss on disturbed watersheds. 

In the most comprehensive landscape assessment

to date—the Interior Columbia Basin Assessment—

current condition of forest and rangeland areas had

drastically departed from the historical condition.

Fire suppression and harvest of the large pine trees

resulted in the buildup of fuels and changes in the

ponderosa pine forests. Rangelands have been invaded by exotic weeds. Different management scenarios

were modeled out over the next 100 years. 

The model found that, at the landscape scale, current momentum toward further departure from the

desired condition will not be overcome in the next

100 years, even with the most aggressive proposed

management. Management could not reverse the

trend of forest changes at current or reasonably foreseeable levels of staff, activities, and budget. 

The sobering news is that, in the Interior Columbia Basin, forest and range health restoration will proceed at such a slow rate that unnaturally large,

high-intensity fires will continue to reset landscape

vegetation. This is probably true in many other areas

as well. These findings suggest that a more realistic

assessment of the prospects for success is needed;

effective restoration of all degraded areas is simply

not feasible. We do not have the resources to make a

difference at landscape scale unless we strategically

focus our restoration efforts. Focusing on selected

watersheds at the scale of 200,000 to 500,000 acres,

where we can hope to make a difference, is a more

realistic and promising approach.

WETLANDS AND RIPARIAN AREAS

Of the nearly 192 million acres managed as national

forests and grasslands, fewer than 10 percent are considered wetlands and riparian areas. Higher percentages are found in Regions 8, 9, and 10 with

significantly lower percentages (less than 2 percent) in

the arid and semi-arid portions of Regions 1, 2, 3, 4, 5,

and 6. These are rough estimates because the Forest

Service has not conducted specific inventories of these

areas. Because of their limited extent and usually narrow configuration, wetlands and riparian areas have

often been mapped as inclusions in larger mapping

units during soil surveys, range analysis, and other

inventory and analysis efforts. A more definitive estimate is needed for improved management.

These areas are often the most productive and

most used portions of the landscape because they

have more available water, deeper and more fertile

soils, robust vegetation, and cooling shade. Riparian

and wetland areas also receive the most intense use

because they provide abundant forage for wildlife and

Watershed Condition 

and Restoration

N
19

domestic livestock, serve as transportation corridors,

commonly produce quality timber, concentrate recreational use, and may hold valued minerals. 

The total grazing use of Federal lands has decreased

steadily since the mid-1950’s. However, in the Pacific

Northwest, grazing has increased on private lands near

waterbodies and in riparian areas, bringing corresponding increases in grazing-related damage to riparian

function and watershed condition. 

The condition of riparian areas and wetlands varies

considerably across the Nation, depending on a number of physical and land use factors. Estimates indicate that conditions on national forest lands are good

in over 90 percent of Alaska, 70 percent of the East,

60 percent of the South, and in the West ranges from

over 50 percent in the more humid sections to less

than 30 percent in semiarid and arid areas. Reasons

for poor conditions vary significantly across the country. Past timber harvest, roading, recreation, and

urban encroachment account for much of the problems in the East, South, Alaska, and humid portions

of the West. Livestock grazing, roading, recreation,

mining, and urban encroachment account for much

of the concern in the drier parts of the West. 

Although these areas are easily overused and damaged, they also respond quickly to improved management. Watershed improvement programs, fisheries

habitat improvements, range betterment efforts,

enlightened road placement and maintenance, and

restoration of abandoned mines all contribute to

improving these important areas. Key elements of the

Forest Service’s Natural Resources Agenda and Clean

Water Action Plan focus on restoring and managing

wetland and riparian areas.

ROADS

After the Second World War, the growing demand for

wood products fueled an exponential growth in forest

road mileage. From a limited mileage in 1960, the

system of forest roads has grown to more than

400,000 miles. During this period, conventional wisdom held that as long as a road remained intact—

comfortably drivable—the surrounding area would

benefit from increased access. People also believed

that adverse effects from roads could be corrected and

that physical and biological resources would not suffer long-term changes. The engineering emphasis was

on protecting the road from damage by water; other

physical or biological effects received little attention.

In fact, many roads posed severe problems and risks

for forest resources, both as land disturbance and as

Watershed Condition 

and Restoration

● ●

●● ●●

●●●

● ● ●

●

●

●

●

●

●

●●

●

●

●

●

●

●

●

●

● ●

●

●●

●●

●

●

●

●

●●

●

● ●

●

●

●●

●

●

●

■ ■■

■

■

■

■

■

■

■

■

■ ■

■ ■

■

■

■

■

■

■

■

■

■

■

■

■

Example:

Slope Position – Layer

Watershed – Scale

Bluff Creek Watershed

Orleans Ranger District

Six Rivers National Forest

Acres: 47,417

Road miles: 224

Distribution of failure

sites by slope position

Upper: 3

Middle: 32

Lower: 44

Distribution of road

miles by slope position

Upper: 103

Middle: 78

Lower: 43

Failures per mile by

slope position

Upper: 0.03

Middle: 0.41

Lower: 1.03

Road failure sites

Surface erosion

(27 sites)

Mass wasting

(52 sites)

Blue-line streams

Road systems

Decommissioned

roads

Slope position

Upper

Middle

Lower

N 0 1

1:115,000 Miles

2

Figure 16. Road failures are strongly related to slope position in this

northern California watershed. Note that most of the failures are in middle

and lower positions, with only three in the upper slope position (USDA

Forest Service 1999). Effects vary greatly among roads, and substantial

effort is needed to distinguish high-impact and low-impact roads to set priorities for watershed restoration. 
20

access routes that concentrate human activities and

pollution. Damages to watersheds and aquatic and

riparian ecosystems accumulated in many places. 

In recent years, a growing concern for water quality, runoff, and flood damage in forests and rangelands

has focused attention on roads and their effects on

water quality and watershed functions. The current

Forest Service Natural Resources Agenda reflects this

concern. 

Many studies have shown that roads in forests have

elevated erosion rates and often increase the

likelihood of landslides in steep or unstable terrain.

Both of these effects can be especially pronounced

where roads cross or run near streams, resulting in

sediment discharge to surface waters. Roads are also

likely sites for chemical spills associated with traffic

accidents, with the highest risk of water contamination where roads cross streams. Proper road engineering, application of Best Management Practices (BMP),

and emergency preparedness can reduce but not eliminate these risks. Unfortunately, most of the roads on

national forests and grasslands were built before current engineering practices and BMP’s were used, and

the cost of upgrading to current standards is high.

Other transportation corridors, such as pipelines and

powerline rights-of-way, also pose problems and risks. 

Not all roads have the same effects on watersheds.

Variation is great and discriminating between highimpact and low-impact roads and road networks is an

important analytical challenge. For example, studies

on national forest watersheds in northern California

(USDA 1999) found that roads at or near ridgetops had

far fewer failures and generated far less sediment to

streams than roads in lower slope positions (see figure

16) . The specific effects of roads are strongly

influenced by a variety of factors, including road building techniques, soils and bedrock, topography, and

severity of storm events.

Research has shown that improved design,

construction, and maintenance can reduce the effects

of roads on water quality, wetlands, and watershed

function. Remarkably little is known about road effects

on hydrology at watershed and subbasin scales, so

there is inadequate basis to evaluate the hydrologic

functioning of the road system at large scales. Analytical techniques need to be developed further. The specific range of ongoing and likely watershed effects should

be evaluated at both regional and landscape scales. ❖

Watershed Condition 

and Restoration
21

In conserving and recovering at-risk

species and maintaining biodiversity, a

strong consensus among conservation

biologists supports the need for refugia

or designated areas capable of providing high-quality

habitat. For aquatic species, watersheds are the basic

unit for such a conservation strategy. Watersheds that

have maintained hydrologic functions and processes,

and those that support healthy populations of the

species of interest or their specific habitats have been

identified. These areas receive a combination of lowrisk land allocations, special land-use standards, or

priority for analysis and restoration efforts. 

Networks of refugia must be large and well distributed to anchor the persistence and recovery of the atrisk species in current and future disturbance regimes

and ever-changing landforms and vegetation cover.

Refugia alone are not assumed to be sufficient to conserve species. Lands between refugia are expected to be

subject to land allocations and practices that will promote watershed function and conserve species, complementing the special focus on refugia. 

Some aquatic species (for example, invertebrates)

depend on local habitats. They may exist only in a single spring or a spring-stream system in a single

watershed. Where habitats are isolated or unique

(because of water chemistry, vegetation, and a multitude of contributing factors), the potential for rare

species is high. The distribution of these habitats is

not restricted to any set of watersheds, lithology, or

other ecological units. The importance of these “rare”

habitats must be recognized, with proper inventory

and site-specific protection measures. 

Where lands are set aside or allocated for special

low-risk management, broad conservation benefits

accrue, not just for targeted rare species, but for biodiversity and watershed health as well. These areas

provide a hedge against unanticipated problems with

species viability and large-scale disturbances and climate changes. 

Five recent, large-scale, ecosystem-based Forest

Service assessments have identified networks of

aquatic conservation watersheds: the Northwest Forest Plan (FEMAT 1993), the Interior Columbia Basin

Ecosystem Management Project, The Tongass National Forest Land Management Plan, the Sierra Nevada

Framework Project, and the Southern Appalachians

Assessment. 

Of these, the Northwest Forest Plan and the Tongass National Forest Land Management Plan have

records of decision that delineate key watersheds or

central areas for biodiversity. The stage is set and

progress is being made in the other areas to identify

special emphasis watersheds and to protect and,

where needed, restore them.

Conserving Aquatic Biodiversity 

and Threatened Species

Table 3. Land areas identified for aquatic conservation, biodiversity, and

clean water in various recent large-scale ecosystem analyses.

I

Assessement Area Number of Refugia Total area, refugia Proportion of

watersheds watersheds (acres) total NF area*

Northwest Forest Plan 164 8,678,600 (includes BLM lands) 33%

(key watersheds) 1

Tongass National Forest 2 Too many to count 13,662,000** 80%

Interior Columbia Basin 1,693 19,977,824 (includes BLM) 40%

(strongholds) 3

Sierra Nevada 4 139 5,747,261 47%

(proposed emphasis watersheds)

Southern Appalachians 45 10,303,360 (17% is National Forest) 38%

(aquatic diversity areas) 5

*In the analysis area. 

** Conserve and restore land-use designations

1. FEMAT 1994.

2. Tongass Land Management Plan revision, 1997.

3. Interior Columbia Basin Ecosystem Management Project.

4. Draft information from of the Sierra Framework project, Pacific

Southwest Region (Joseph Furnish, pers. comm). 

5. Southern Appalachian Assessment.
22

These efforts represent a substantial actual and

potential commitment of lands to conserving aquatic

species and could be regarded as a major part of a

national forest aquatic and biodiversity conservation

strategy. More than 53 percent of national forest lands

are represented by the assessments in table 3. The

role that the national forest lands play in anchoring

fish and other aquatic species is not trivial, with

greater than one-third of national forest lands identified as important to maintaining aquatic biodiversity. 

The Inland West Water Initiative, which includes

Regions 1, 2, 3, and 4, will have completed its assessment and delineated special waterbodies and watersheds by early FY 2000. The asssessment will identify

which watersheds are important and for what purposes (in a spatially explicit format), for more than 80

percent of national forest lands in the four regions. 

Recent strategies for national forests have focused

on restoring the natural ecological processes that will

create and maintain diverse and resilient aquatic habitat (Northwest Forest Plan, Tongass National Forest,

PACFISH; proposed for the Sierra Nevada provinces

and the Interior Columbia Basin.) These efforts will

move east and probably be incorporated into revised

forest plans in the next several years. ❖

Conserving Aquatic Biodiversity 

and Threatened Species
23

ational forests typically occupy the headwaters of large river basins. Forest activities affect the water resource; so do

downstream land uses. In general, watersheds on the national forests are in relatively good

shape compared to soils, waters, and riparian areas on

private lands, ranches, and farms, and urban areas

that typically occupy the lower parts of a large river

basin. It will take a comprehensive, watershed

approach to improve water quality or restore the full

range of watershed function to the system. 

Water quality problems, and solutions, are disproportionately tied to urban areas. Urban areas are often

forested and make a major contribution to maintaining and improving water quality. Counties classified

as “urban” now contain one-quarter of the total tree

cover of the coterminous United States. 

Urban trees affect the volume of runoff by intercepting precipitation, slowing water infiltration rates,

and transpiring water. By intercepting and retaining

or slowing the flow of precipitation reaching the

ground, trees (in conjunction with soils) play an

important role in urban hydrologic processes. They

can reduce the rate and volume of storm water runoff,

flooding damage, stormwater treatment costs, and

other problems related to water quality. Estimates of

runoff for an intensive storm in Dayton, OH, showed

that the existing tree canopy (22 percent) reduced

potential runoff by 7 percent and that a modest

increase in canopy cover (29 percent) would reduce

runoff by nearly 12 percent (Sanders 1986). A study of

the Gwynns Falls watershed in Baltimore indicated

that heavy forest cover can reduce total runoff by as

much as 26 percent and increase low-flow runoff by

up to 13 percent, compared with treeless areas, for

equivalent land-use conditions (Neville 1996). Tree

cover over pervious surfaces reduced total runoff by

as much as 40 percent; tree canopy cover over impervious surfaces had a limited effect on runoff. In reducing runoff, trees function like retention structures. In

many communities, reduced runoff from rainfall

interception can also reduce costs of treating

stormwater by decreasing the volume of water handled during periods of peak runoff (Sanders 1986).

Hydrologic costs may also be associated with urban

vegetation, particularly in arid environments where

water is increasingly scarce. Increased water use in

desert regions could alter the local water balance and

various ecosystem functions tied to the desert water

cycle. In addition, annual costs of water for sustaining

vegetation can be twice as great as energy savings

from shade for tree species that use large amounts of

water, such as mulberry (McPherson and Dougherty

1989). In Tucson, AZ, 16 percent of the annual irrigation requirement of trees was offset by the amount of

water conserved at power plants because of the energy

savings from trees (Dwyer et al. 1992).

Urban waterways are strongly influenced by impervious surfaces that generate large volumes of rapid

surface runoff, contaminants, and thermal loads. The

effects of temperature extremes, nutrient loading, toxins, bed instability, current velocities, and disturbance

frequencies are all magnified in urban watersheds.

Urban vegetation can reduce many of these adverse

effects by cooling air temperatures, shading

waterways, removing pollutants from both water and

air, reducing surface and subsurface flows, and by

reducing pollutant emissions from various sources

(Nowak et al. 1998).

POLICY IMPLICATIONS

Research is critically needed that integrates these

numerous vegetation effects to evaluate the total

effects of urban vegetation and various vegetation

designs on water quantity and quality. This research

should include field measurements, computer modeling, and model validation. The Baltimore long-term

ecosystem research project is currently investigating

and integrating many of these research issues to help

answer this complex question. More research and field

measurements are needed to determine appropriate

urban vegetation management strategies and designs

to improve water and stream quality in and around

urban areas, and consequently improve human health

and environmental quality in the Nation. ❖

Integrating Watersheds from the 

Headwaters Through the Cities

N
24

his report contains information that can

be used to help articulate and guide the

agency’s commitment to watershed

health and restoration. The report is a

first step in identifying the particular role of national

forests in providing water to the Nation and restoring

watersheds to a healthy, sustainable functioning condition

The report has focused on answering basic questions about the quantity, quality, uses, and value of

waters that flow from the national forests; about the

condition and trend of national forest watersheds; and

about strategies for protecting and restoring degraded

waters and watersheds. We have surveyed the

published information and tried to capture the current state of our understanding in this paper—though

in sharply condensed form. Along the way, we have

noted gaps in the data and questions particularly ripe

for further inquiry. Action items for additional investigation include:

■ Refine water-yield estimates to the national forest

scale. Precision estimates by forest and State are

necessary to drive water valuation models and aid

in revising forest plans. This action could be completed in 6 to 12 months, with a term or post-doctoral position. 

■ Refine our estimate of the value of water on and

flowing from national forest lands. The estimate of

the value of water from national forest lands in

this paper is a first approximation that does not

include dilution, navigation, quality of water, and

nonuse values nor does it estimate the value of

careful forest management in sustaining a watershed’s ability to store and distribute water and

moderate downstream flooding. 

■ Convene a leadership forum to examine the particular role that the Forest Service plays in providing

clean water to the Nation and determine the kinds

of watershed and forest management programs that

will maintain long-term, high-quality water and

keep national forest watersheds operating within

their historical range of variability. 

■ Develop and activate a communications strategy

on the connection of forested watersheds and clean

water in urban settings, addressed to urban and

suburban publics and policymakers. This strategy

would highlight the contributions that national

forest lands, technical assistance, and stewardship

programs can make to water quality, reduced

storm runoff, drought reduction, and watershed

health. 

■ Complete an agency-wide assessment of specialemphasis and biodiversity watersheds, modeled on

the assessment work of the Inland West Water

Institute. 

In the meantime, the Forest Service is actively

pursuing initiatives to restore watersheds, improve

water quality, and protect aquatic habitats. The Chief

has made watershed health and restoration,

recreation, sustainable forestry, and roads management the agency’s top priorities. The Committee of

Scientists recommended that the Secretary of Agriculture highlight the need to plan for conserving and

restoring watersheds through maintaining flow

regimes. These efforts recognize that watershed

integrity will be maintained and restored, in part,

through sustainable management of the national

forests. But watersheds are larger than forests, watershed health will be achieved only through collaborative partnership efforts at the watershed scale as

envisioned in the Clean Water Action Plan headed by

the Administrator of the EPA and Secretary of Agriculture. The Forest Service has a vital role to play on

both sides of the national forest boundaries.

The challenge for watershed-based approaches will

be to develop a shared vision for healthy and productive watersheds, based on understanding natural and

human-induced variability at scales ranging from small

(<20,000 acre) to large (>1,000,000 acre). New strategies are needed for managing in mixed-ownership

watersheds, as well as creating new partnerships for

effective learning, assimilating new knowledge, and

implementing our shared vision. ❖

Next Steps

T
25

Brown, T. 1999. Notes on the Economic

Value of Water from National Forests.

Unpublished report. USDA Forest Service, Rocky Mountain Research Station,

Fort Collins, CO.

Coleman, E.A. 1953. Vegetation and Watershed Management. The Ronald Press.

Croft, A.R. and Bailey, Reed W. May 1964.

Mountain Water. USDA Forest Service,

Intermountain Region, Ogden, UT

Dwyer, J.F., Nowak, D.J., Noble, M.H., and

Sisini, S.M. (in press). Connecting People with Ecosystems in the 21st Century:

An Assessment of our Nation’s Urban

Forests (PNW GTR xxx): U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station.

Portland, OR.

Forest Ecosystem Management Assessment

Team: An Ecological, Economic, and

Social Assessment Report of the Forest

Ecosystem Management Assessment

Team (FEMAT) 1993.

Frederick, K. D. and Sedjo, R. A. 1991.

America’s Renewable Resources: Historical Trends and Current Challenges.

Resources for the Future, Washington,

DC.

Frederick, K. D. 1991. Water Resources:

Increasing Demand and Scarce Supplies.

In: America’s Renewable Resources: Historical Trends and Current Challenges,

Kenneth D. Frederick and Roger A.

Sedjo, eds., Resources for the Future,

Washington, DC.

Gillian, D.M. and Brown, T.C. 1997.

Instream flow protection: Seeking a

balance in western water use. Island

Press, Washington, DC.

Gleick, P. H. 1993. Water in Crisis: A

Guide to the World’s Fresh Water

Resources. Oxford University, Oxford.

Gleick, P. H. 1998. The World’s Water: The

Biennial Report on Freshwater Resources.

Island Press. Washington, DC. 

Graf, W.L. 1999. Downstream Geomorphic

Impacts of Large Dams on American

Rivers. Arizona State University, Department of Geography, Tempe, AZ, (unpublished manuscript). 

Hansen, T. and Hallum, A. 1990. Water allocation tradeoffs: Irrigation and recreation. Agricultural Economic Report

number 634, Resources and Technology

Division, Economic Research Service, 

U.S. Department of Agriculture. 

Hann, W.J., Jones, J.L, Karl, M.G. [et al.]

1997. Landscape dynamics of the basin.

In Quigley, T.M.; Arbelbide, S.J., (tech.

eds.). An assessment of ecosystem components in the interior Columbia Basin

and portions of the Klamath and Great

Basins. Gen. Tech. Rep. PNW-GTR-405,

Chapter 3. U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. Portland, OR.

Harr, R. D. 1983. Potential for Augmenting

Water Yield Through Forest Practices in

Western Washington and Western Oregon. Water Resources Bulletin

19(3):383-394.

Kattelmann, R. C., Berg, N. H., and Rector,

J. 1983. The Potential for Increasing

Streamflow from Sierra Nevada Watersheds. Water Resources Bulletin

19(3):395-402.

MacCleery, D. W. 1992. American Forests:

A History of Resiliency and Recovery.

USDA Forest Service, FS-540, in cooperation with the Forest History Society,

Durham, NC.

McPherson, E.G. and Dougherty, E. 1989.

Selecting trees for shade in the Southwest, J. Arboriculture 15:35-43.

Modeling the effects of urban vegetation on

air pollution, In: Air Pollution Modeling

and Its Application XII. (S. Gryning and

N. Chaumerliac, eds.) Plenum Press,

New York, pp. 399-407.

Neville, L.R. 1996. Urban Watershed Management: the Role of Vegetation. Ph.D. dissertation, SUNY College of Environmental

Science and Forestry, Syracuse, NY. 

Moody, D.W. 1990. Groundwater contamination in the United States. Journal of Soil

and Water Conservation 45: 170-179.

National Research Council. 1992. Restoration of aquatic ecosystems. National

Academy Press, Washington, DC. 

The Nature Conservancy. 1996.

Aquatic/Wetland Species at Risk Map, in:

The Index of Watershed Indicators, U.S.

EPA. EPA-841-R-97-010, September

1997. p. 22

Neilson, Ronald. 1995. A model for predicting continental-scale vegetation distribution and water balance. Ecological

Applications 5(2):362-385.

Noble, E. 1965. Sediment Reduction

through Watershed Rehabilitation. USDA

Agricultural Research Service, Washington DC. Paper 18, Interagency Sedimentation Conference 1963, p. 114-123. In:

Proc. Fed. Misc. Pub. 970

Nowak, D.J., Civerolo, K.L., Rao, S.T., Sistla,

G., Luley, C.J., and Crane, D.E., in

review. The impact of urban trees on

ozone in the Northeastern United States.

Atmos. Env. 

Pinchot, G. 1947. Breaking New Ground.

Harcourt and Brace, New York.

Rodgers, A. D. III. 1991. Bernard Eduard

Fernow: A story of North American

Forestry. Forest History Society,

Durham, NC.

References
26

Sanders, R.A. 1986. Urban vegetation

impacts on the urban hydrology of Dayton Ohio, Urban Ecology 9:361-376.

Schmidt, L. J. and Solomon, R.M. 1981.

The National Forest Role in Augmenting

the Drop of Water. In: Arizona Water

Symposium 25th Annual Proceedings,

Arizona Department of Water Resources,

Report #3.

Shiklomanov, I. A. 1993. World Fresh Water

Resources. In: Water in Crisis: A Guide

to the World’s Fresh Water Resources.

Oxford University Press, Oxford.

Solley, W. B., Pierce, R., Perlman, H. 1998.

Estimated use of water in the United

States. In: 1995 U.S. Geological Survey.

Circular 1200, Denver, CO.

Souch, C.A. and Souch, C. 1993, The effect

of trees on summertime below canopy

urban climates: a case study, Bloomington, Indiana. J. Arboric. 19(5):303-312.

Steen, H. K. 1991. The Beginning of the

National Forest System. FS-488, USDA

Forest Service. Washington DC

Taha, H. 1996. Modeling impacts of

increased urban vegetation on ozone air

quality in the South Coast Air Basin,

Atmos. Env. 30(20):3,423-3,430.

Tongass National Forest, Land and Resource

Management Plan, Record of Decision,

signed April 12, 1999.

USDA Forest Service. 1998. Land Areas of

the National Forest System, 1997. FS383. Washington, DC. 

USDA Forest Service. 1999. Roads Analysis:

Informing Decisions About Managing

the National Forest Transportation System. FS-643. Washington, DC.

U.S. Water Resources Council. 1978. The

Nation’s Water Resources 1975-2000.

Washington, DC: Government Printing

Office.

U.S. Water Resources Council, Second

National Water Assessment, Vol. I: Summary, 052-045-00051-7, Washington,

DC: Government Printing Office, 1978.

pp. 20, 21. 

Ziemer, R. 1987. Water Yields from Forests:

An Agnostic View. In: R.Z. Callaham and

J.J. DeVries (Tech. Coord.) Proceedings

of the California Watershed Management

Conference, November 18-20, 1986,

West Sacramento, CA. 74-78. Wildland

Resources Center, University of California, Berkeley CA. Report 11, Feb. 1982.

References
C
D

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its

programs and activities on the basis of race, color, national origin, gender,

religion, age, disability, political beliefs, sexual orientation, and marital or

family status. (Not all prohibited bases apply to all programs.) Persons with

disabilities who require alternative means for communication of program

information (Braille, large print, audiotape, etc.) should contact USDA’s 

TARGET Center at (202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil

Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW,

Washington, DC 20250-9410 or call (202) 720-5964 (voice or TDD). USDA is

an equal opportunity provider and employer.