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The California Water Plan Update BULLETIN 160-98

nine RWQCBs are responsible for enforcing compliance

with NPDES, including pretreatment regulations.

It is, however, the responsibility of the publicly-owned

wastewater treatment plants accepting industrial

wastes to ensure that industries are complying

with pretreatment requirements. RWQCBs conduct

regular inspections on permitted discharges and

respond to public complaints on illegal discharges.

Wastewater treatment facilities operated under

NPDES have, in general, been successful in maintaining

the quality of California’s water bodies. However, the

discharge permits do not regulate all constituents that

may cause adverse impacts. For example, the discharge

of organic materials that contribute to the formation

of DBPs in drinking water is not regulated. NPDES

does not guarantee elimination of pathogens such

as Giardia and Cryptosporidium, which are harder

to inactivate (disinfect) than most other waterborne

pathogens. In addition, permitted discharges can

include nitrogen compounds that can be harmful to

aquatic life, cause algae growth in surface water bodies,

and force downstream drinking water facilities to

increase their use of chlorine or to switch to alternative

disinfection processes. Some wastewater treatment

plant processes do not completely remove all synthetic

chemicals that can be present in the water.

Many municipal wastewater treatment plants discharge to surface waters which are subsequently diverted

for urban use. For example, the larger wastewater

treatment plants discharging to the Sacramento and

San Joaquin river systems above the Delta contribute

an average daily discharge volume of almost 250 mgd

(280 taf/yr) to the system.

Recently, there has been increasing concern about

contamination of drinking water sources by methyl

tertiary butyl ether. MTBE is a compound added to

gasoline to promote more complete combustion and

reduce exhaust emissions. In California, MTBE is used

to reduce exhaust emissions and to meet federal Clean

Air Act requirements for oxygenated gasoline. MTBE

is now being found in wells and reservoirs used for

municipal water supply.

In drinking water, MTBE causes taste and odor

problems at low concentrations. The EPA drinking

water advisory of 20 to 40 ug/L or below to protect

consumer acceptance of drinking water (taste and odor)

would also provide a large margin of protection from

MTBE’s carcinogenic effects and noncancer toxicity.

In California, an action level of 35 ug/L in drinking

water has been issued.

To evaluate the presence of MTBE in California’s

drinking water supplies, voluntary testing for MTBE

was implemented in 1996 by water suppliers in response

to a DHS request. In February 1997, a regulation was

adopted requiring public drinking water systems to

monitor their drinking water sources for MTBE as an

unregulated chemical (a chemical for which there is

no established regulatory or enforceable drinking water

level or maximum contaminant level). Because MTBE

is an unregulated chemical, water suppliers will be

monitoring and reporting MTBE in sources of drinking

water at least once every three years.

The most extensive MTBE contamination of

drinking water sources in California was at two well

fields (Charnock and Arcadia) in Santa Monica. This

contamination was discovered in February 1996, not

long after DHS’ request for voluntary testing for

MTBE. These well fields supplied 80 percent of Santa

Monica’s municipal water. MTBE concentrations as

high as 610 mg/L were observed in the Charnock

well field and seven wells in the field were closed. In

the Arcadia well field, two wells were closed due to

contamination from an underground storage tank at

a nearby gasoline station.

As noted in Chapter 2, legislation enacted in 1997

required DHS to begin adopting primary and secondary

drinking water standards for MTBE. The secondary

drinking water standard for MTBE was to be established by July 1, 1998, and the primary drinking water

standard was to be established by July 1, 1999.

The Office of Environmental Health Hazard

Assessment released a draft technical document entitled

Public Health Goal for Methyl Tertiary Butyl Ether

(MTBE) in Drinking Water in April 1998. This draft

document provided a review of toxicological studies

and other reported data related to the adverse effects

of exposures to MTBE. Based on the comprehensive

review, OEHHA proposed to adopt a drinking water

public health goal of 14 ug/L.

PHGs adopted by OEHHA are used by DHS in

establishing State MCLs. PHGs are based solely on

scientific and public health considerations without

regard to economic cost considerations. Drinking

water standards adopted by DHS also take into consideration factors related to economic and technical

feasibility. PHGs established by OEHHA are not

regulatory levels and represent only non-mandatory

goals. Federal law requires that MCLs established by

DHS must be at least as stringent as the federal MCL

(if one exists).

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Establishing and Meeting

Water Quality Standards

The establishment and enforcement of water quality

standards for water bodies in California falls under the

authority of SWRCB and the nine RWQCBs. The

RWQCBs protect water quality through adoption of

region-specific water quality control plans, commonly

known as basin plans. In general, water quality control

plans designate beneficial uses of water and establish

water quality objectives designed to protect them. The

designated beneficial uses of water may vary between

individual water bodies; some are listed in Table 3-26.

Water quality objectives are the limits or levels

of water quality constituents or characteristics which

are established to protect beneficial uses. Because a

particular water body may have several beneficial uses,

the water quality objectives established must be protective of all designated uses. When setting water quality

objectives, several sources of existing water quality

limits are used (Table 3-27), depending on the uses

designated in a water quality control plan. When more

than one water quality limit exists for a water quality

constituent or characteristic (e.g., human health limit

vs. aquatic life limit), the more restrictive limit is used

as the water quality objective. Table 3-28 lists some

typical water quality constituents or characteristics for

which water quality objectives may be established in

water quality control plans.

Drinking Water Standards

Drinking water standards for a total of 81 individual drinking water constituents (Table 3-29) are in

place under the mandates of the 1986 SDWA amendments. Using the new SDWA standard setting process

established in the 1996 amendments, EPA will select

at least five new constituents from the candidate list

published in March 1998 and will determine whether

to regulate them by August 2001. EPA

will publish a contaminant candidate list and select

constituents for regulation every five years thereafter.

The agency may promulgate an interim national primary

drinking water regulation for a contaminant without

making the required determination or analysis to

address an urgent threat to public health. Selection of

the new constituents for regulation must be geared

toward contaminants posing the greatest health risks.

Occasionally, drinking water regulatory goals may

conflict. For example, concern over pathogens such as

Cryptosporidium spurred a proposed rule requiring

more rigorous disinfection. At the same time, there

was considerable regulatory concern over THMs and

other DBPs resulting from disinfecting drinking water

with chlorine. If disinfection is made more rigorous,

TABLE 3-26

A Partial List of Potential Beneficial

Uses of Water

Municipal and Domestic Supply

Agricultural Supply

Industrial Supply

Groundwater Recharge

Freshwater Replenishment

Navigation

Hydropower Generation

Recreation

Commercial and Sport Fishing

Aquaculture

Freshwater Habitat

Estuarine Habitat

Wildlife Habitat

Preservation of Biological Habitats of Special

Significance

Preservation of Rare, Threatened, or Endangered

Species

Migration of Aquatic Organisms

Spawning, Reproduction, and/or Early Development

Shellfish Harvesting

TABLE 3-28

A Partial List of Water Quality Constituents

or Characteristics for Which Water Quality

Objectives May Be Established

Chemical Constituents Pesticides

Tastes and Odors pH

Human Health and Radioactivity

Ecological Toxicity

Bacteria Salinity

Biostimulatory Substances Sediment

Color Settleable Material

Dissolved Oxygen Suspended Material

Floating Material Temperature

Oil and Grease Turbidity

TABLE 3-27

A Partial List of Existing Water Quality Limits

Drinking Water Maximum Contaminant Levels

Drinking Water Maximum Contaminant Level Goals

State Action Levels and Recommended Public Health

Levels for Drinking Water

EPA Health Advisories and Water Quality Advisories

National Academy of Sciences Suggested No-AdverseResponse Levels

Proposition 65 Regulatory Levels

EPA National Ambient Water Quality Criteria

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DBP formation is increased. Poor quality source waters

with elevated concentrations of organic precursors or

bromides complicate the problem of reliably meeting

standards for disinfection while meeting standards for

DBPs. The regulatory community must balance benefits

and risks associated with efficient disinfection and

against higher DBP levels.

EPA promulgated its Information Collection Rule

in 1996 to obtain data on the tradeoff posed by simultaneous control of DBPs and pathogens in drinking

water. The ICR requires all large public water systems

to collect and report data on the occurrence of DBPs

and pathogens (including bacteria, viruses, Giardia, and

Cryptosporidium) in drinking water over an 18-month

period. With this information, an assessment of health

risks due to the presence of DBPs and pathogens in

drinking water can be made. EPA can then determine

the need to revise current drinking water filtration and

disinfection requirements, and the need for more

stringent regulations for disinfectants and DBPs.

Source Water Protection/Watershed

Management Activities

The 1996 reauthorization of the federal SDWA

requires states to conduct source water assessments and

encourages states to establish watershed protection

programs. In response to this amendment, DHS, in

cooperation with SWRCB, is preparing a drinking

water source assessment and protection program.

Key elements of this program include delineation of

the area surrounding the water source, an inventory

of possible contaminating activities, and an analysis

of the vulnerability of the drinking water source to

contamination. The program draft must be submitted

to EPA for approval by February 1999. The assessments must be completed in 2003.

California’s DWSAP program will cover both

groundwater and surface water sources. Since California

has not developed a wellhead protection program as

required by the 1986 SDWA amendment, the groundTABLE 3-29

Constituents Regulated Under the Federal Safe Drinking Water Acta

1,1-Dichloroethylene Chromium Methoxychlor

1,1,1-Trichloroethane cis-1,2-Dichloroethylene Nickel

1,1,2-Trichloroethane Copper Nitrate

1,2-Dibromo-3-chloropropane (DBCP) Cyanide Nitrite

1,2-Dichlorobenzene Dalapon Oxamyl

1,2-Dichloroethane Dichloromethane Pentachlorophenol

1,2-Dichloropropane Dinoseb Phthalates

1,2,4-Trichlorobenzene Diquat Picloram

1,4-Dichlorobenzene Endothall Polychlorinated biphenyls (PCBs)

2,3,7,8-TCDD (Dioxin) Endrin Polynuclear Aromatic Hydrocarbons (PAHs)

2,4-Dichlorophenoxyacetic acid (2,4-D) Epichlorohydrin Radium 226

2,4,5-TP (Silvex) Ethylbenzene Radium 228

Acrylamide Ethylene dibromide (EDB) Selenium

Adipates Fluoride Simazine

Alachlor Giardia lamblia Styrene

Antimony Glyphosate Tetrachloroethylene

Arsenic Gross alpha particle activity Thallium

Asbestos Gross beta particle activity Toluene

Atrazine Heptachlor Total coliforms

Barium Heptachlor epoxide Total trihalomethane

Benzene Heterotrophic bacteria Toxaphene

Beryllium Hexachlorobenzene trans-1,2-Dichloroethylene

Cadmium Hexachlorocyclopentadiene Trichloroethylene

Carbofuran Lead Turbidity

Carbon tetrachloride Legionella Vinyl chloride

Chlordane Lindane Viruses

Chlorobenzene Mercury Xylenes (total)

a

 As of February 1997.

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within SWP and CVP service areas outside of the

Central Valley. Some water quality actions being

considered by CALFED include:

• Reducing concentrations of heavy metals from mine

drainage entering the Delta and its tributaries.

• Reducing pollutant concentrations entering the

Delta from the San Joaquin River.

• Reducing vulnerability of Delta water quality to

salinity intrusion by implementing a Delta longterm protection plan.

• Improving water circulation in the Delta by constructing seasonally operated barriers in south

Delta channels.

• Promoting and supporting efforts of local watershed

programs that improve water quality within the Delta

and its tributaries.

• Reducing urban and industrial pollutants entering

the Delta and its tributaries by controlling urban

and industrial runoff.

• Controlling discharge of domestic wastes from

boats within the Delta and its tributaries.

• Identifying and implementing actions to address

pollution problems in water and sediment within

the Delta and its tributaries.

• Reducing pollutants entering the Delta and its

tributaries from agricultural runoff.

CALFED identified water quality parameters of

concern to beneficial uses and set numerical or narrative

water quality targets for each. These targets represent

desirable instream concentrations of parameters of

concern and would be used as indicators of success to

determine the effectiveness of the water quality actions.

However, the degree to which these targets are realized

will depend upon overall CALFED solutions. Targets

may not be fully realized because of competing CALFED solution requirements or because attainment of

a target is technically infeasible.

Colorado River Water Quality. The Colorado

River is a major source of water supply to Southern

California. The river is subject to various water quality

influences because its watershed is so large. Much of

the watershed is open space and agricultural lands, and

municipal and industrial discharges are not a significant

source of water quality degradation.

Perchlorate has been detected in the Colorado

River. Concentrations ranging from 5 to 9 ug/L have

been found in Lake Havasu. The contamination source

has been traced to manufacturing facilities in the Las

Vegas/Henderson, Nevada, area. Several federal

Superfund sites contribute to uranium contamination

water portion of the DWSAP will serve as the State’s

wellhead protection program. DHS is responsible for

conducting drinking water source assessments, although

any public water agency may perform its own assessment,

provided it conforms to DHS procedures. When a

public water agency has completed an evaluation

through another program, that information may be

submitted for the drinking water source assessment. For

example, drinking water utilities that utilize surface water

sources are required under California law to perform

watershed sanitary surveys every 5 years. Many of the

watershed sanitary surveys completed prior to the

DWSAP program will likely satisfy most requirements

of the assessment process. Local agencies that choose to

conduct their own assessments and implement source

protection may receive financial assistance through the

drinking water state revolving fund loan program.

The potential sources and causes of water quality

impairment vary from watershed to watershed. Table

3-30 lists potential sources and causes of water quality

impairment in a watershed.

A Source Water Protection Example. DHS requested that the Department perform a sanitary survey

of the SWP. The Department’s 1990 initial survey and

1996 update provide an example of factors considered in

source protection studies. Table 3-31 lists some recommendations for action resulting from the sanitary survey.

The 1996 sanitary survey identified the need to

address pathogens such as Giardia and Cryptosporidium

in SWP waters. The survey recommended investigating

each watershed tributary to the SWP to evaluate the

potential sources of pathogens and to develop a

coordinated microbiological monitoring and reporting

system for municipal SWP contractors and agencies.

The Department and MWDSC have implemented a

pathogen monitoring program. Under this program,

regularly scheduled and storm event sampling for

Giardia, Cryptosporidium, and bacteria which serve

as general indicators of microbiological contamination

(such as Clostridium perfringens, Escherichia coli, and

total and fecal coliforms) is conducted at sites

throughout the SWP.

CALFED Bay-Delta Program Water Quality

Planning. CALFED’s goal for water quality is to provide

good water quality for environmental, agricultural,

drinking water, industrial, and recreational beneficial

uses. To achieve this goal, CALFED is developing water

quality actions to address impairments of beneficial

uses in the Bay-Delta, Sacramento River, and San

Joaquin River Watersheds, and in streams and rivers

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The California Water Plan Update BULLETIN 160-98

TABLE 3-30

Potential Sources and Causes of Water Quality Impairment

Source of Pollutant or Stressor Possible Sources

Contamination

Dissolved minerals Mineral deposits, mineralized waters, hot springs,

seawater intrusion

Asbestos Mine tailings, serpentinite formations

Hydrogen sulfide Subsurface organic deposits, such as peat soils in Delta

islands

Metals Mine tailings

Microbial agents Wildlife

Radon Geologic formations

Sediment Forestry activities, stream banks, construction activities,

roads, mining operations, gullies

Altered flow or habitat modification Impoundments, storm water runoff, artificial drainage,

bank erosion, riparian corridor modification

Gasoline Service stations’ underground storage tanks

Solvents Dry cleaners, machine shops

Metals Photo processors, laboratories, metal plating works

Microbial agents Sewage discharges, storm water runoff

Pesticides Storm water runoff, golf courses

Nutrients Storm water runoff

Miscellaneous liquid wastes Industrial discharge, household waste, septic tanks

SOCs, industrial solvents, metals, acids Electronics manufacturing, metal fabricating and plating,

transformers, storage facilities, hazardous waste disposal

Pesticides Chemical formulating plants

Wood preservatives Plants that pressure treat power poles, wood pilings,

railroad ties

Solvents, pesticides, metals, organics, Disposal sites receive waste from a variety of industries,

petroleum wastes, microbial agents municipal solid wastes, petroleum products

household waste

Pesticides, fertilizers, concentrated Tailwater runoff, agricultural chemical applications,

mineral salts, microbial agents, sediment, fertilizer usage, chemical storage at farms and applicators’

nutrients air strips, packing sheds and processing plants, dairies,

feed lots, pastures

Solvents, petroleum products, microbial Earthquake-caused pipeline and storage tank failures and

agents, other hazardous materials damage to sewage treatment and containment facilities,

major spills of hazardous materials, floodwater

contamination of storage reservoirs and groundwater

sources

General

Commercial

Businesses

Municipal

Industrial

Solid Waste

Disposal

Agricultural

Disasters

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The California Water Plan Update BULLETIN 160-98

in the Colorado River watershed. Uranium mining

occurs in the Colorado River Basin above Lake Mead.

As uranium decays, alpha-emitting particles are released.

Although gross alpha levels in Colorado River water

remain under current federal and State MCLs, a slight

upward trend in the levels has been observed.

Salts and turbidity from natural geologic formations

and from agricultural operations are the primary forms

of water quality degradation in the Colorado River.

Unlike Delta soils, Colorado River watershed soils are

low in organic content. As a result, water from the

Colorado River typically has only about one-half the

capacity to produce DBPs during drinking water

treatment as does water from the Delta.

Mineral concentrations in the Colorado River are

usually much higher than those found in water taken

from the Delta. For example, from 1993 to 1995 the

average TDS of Colorado River Aqueduct water was

691 mg/L, while the average concentration in the

California Aqueduct was 236 mg/L. When possible,

MWDSC blends Colorado River water with SWP

water or other sources to reduce salt concentrations in

the water delivered to customers. MWDSC’s interim

policy is to blend SWP water with Colorado River

water to obtain a target TDS level between 500 and

550 mg/L, during April through September. The

agency will adopt a long-term blending policy

following completion of a salinity management study

in 1998 (see Chapter 7).

The federal Colorado River Basin Salinity Control

Act of 1974 authorized and directed the Secretary of

the Interior to construct facilities to control Colorado

River salinity to meet salinity requirements expressed

in Minute 242 of the U.S. - Mexican Treaty. The act

also directed the Secretary to expedite investigation,

planning, and implementation of a salinity control program in the United States upstream of Imperial Dam.

Currently, salinity control activities are removing over

TABLE 3-31

SWP Sanitary Survey Update Recommendations

Water Quality Problem Recommendation

Pathogens Implement pathogen monitoring program

Disinfection By-Product Precursors Investigate possible means of reducing organic carbon levels in the Delta

(Organic Carbon) and North Bay Aqueduct

Disinfection By-Product Precursors Investigate possible means of controlling bromide concentrations in

(Bromide) SWP waters

Dissolved Solids and Turbidity in the Investigate measures to reduce salts and turbidity in the Aqueduct

California Aqueduct

Hazardous Waste Facilities Inventory hazardous waste facilities and volume of hazardous materials

Hazardous Materials Releases Review emergency responses to hazardous materials releases to determine

types/amounts of materials released and potential for contamination in

watershed

Urban Runoff Review storm water discharges from cities and urbanized areas

Barker Slough/North Bay Aqueduct Study watershed to determine sources and extent of contamination

Solid Waste Landfills Review solid waste landfills in SWP watersheds

Underground Storage Tanks Evaluate status of leaking underground storage tanks within

SWP watersheds

Petroleum Product Pipelines Review pipeline failures resulting in petroleum releases to determine

potential for SWP contamination

Emergency Action Plan Review SWP emergency action plan to ensure document is up-to-date

and functionally adequate

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600,000 tons of salt per year from the river system. To

maintain the 1975 federally approved salinity standards

for the basin it is estimated that by 2010 approximately

1.5 million tons of salt will have to be removed each year.

An example of a salinity control measure in the

basin is USBR’s Yuma desalting plant, constructed to

treat agricultural drainage from Arizona’s WelltonMohawk Irrigation and Drainage District. The plant,

said to be the world’s largest reverse osmosis desalter,

has a capacity of 73 mgd. Plant construction was

completed in 1992, and USBR began operating the

plant at one-third capacity. A flood event in the Gila

River along with above normal runoff in the Colorado

River watershed in years since then has reduced the

salinity of Colorado River water, permitting the plant

to be taken off-line. Currently, agricultural drainage is

bypassed through a concrete-lined canal to the Cienega

de Santa Clara in Mexico, as long as Minute 242 water

quality requirements are being met. Other salinity

control measures implemented in Wyoming, Utah,

Colorado, and Nevada have included lining or piping

irrigation delivery systems, deep well injection of brines,

plugging of flowing brine wells, erosion control on

saline lands, and irrigation improvements.

Groundwater Quality

Groundwater pollution presents a serious challenge

in California. A variety of contaminants have been

found in groundwater; most have been introduced by

human activities. Prominent among these are nitrates

and chemicals such as pesticides and solvents. Most

groundwater contamination sites are small and seldom

affect water supplies on a regional basis. These sites may

require cessation of pumping from one or two water

supply wells, or the installation of wellhead treatment.

TABLE 3-32

Waterborne-Disease Outbreaks Associated with Groundwater

Used as a Drinking Water Source, 1993-94

State Date Pathogen Organism No. of

Type Cases

Minnesota November 1993 Campylobacter jejuni Bacterium 32

Missouri November 1993 Salmonella serotype Typhimurium Bacterium 625

New York June 1993 Campylobacter jejuni Bacterium 172

Pennsylvania January 1993 Giardia lamblia Protozoan 20

South Dakota September 1993 Giardia lamblia Protozoan 7

Washington April 1993 Cryptosporidium parvum Protozoan 7

Idaho June 1994 Shigella flexneri Bacterium 33

Minnesota June 1994 Campylobacter jejuni Bacterium 19

New York June 1994 Shigella sonnei Bacterium 230

Washington August 1994 Cryptosporidium parvum Protozoan 134

Of greater water supply concern from a statewide

perspective are areas of regional groundwater contamination—such as organics in the San Gabriel Valley or

nitrates in parts of the San Joaquin Valley—which require a significant reconfiguration of local agency water supply systems. Another important consideration

in evaluating larger-scale groundwater contamination

problems is the treatment preference now accorded to

groundwater sources under the SDWA. Because the

SDWA is imposing more stringent requirements on

treatment of drinking water from surface sources,

many communities are planning to meet their future

municipal needs by turning to groundwater.

In California, nitrates in groundwater are widespread (see Chapter 5). Nitrates may enter the soil as a

result of fertilizer application, animal waste, septic

tanks, industrial disposal, wastewater treatment plant

sludge application, or other sources. Certain organisms

have the capacity to take nitrogen from the air and

convert it to nitrates. In California, the most significant

source of nitrates in soils is from agricultural practices,

primarily farming operations and animal husbandry.

Nitrates can move through the soil into groundwater

and, once there, may seriously degrade its usability.

Nitrate removal is expensive; therefore, it is often not

cost effective to treat nitrate-contaminated waters.

There has been growing concern over the potential

human health threat of pathogens in groundwater used

as drinking water. This concern stems from pathogens

such as Giardia, Cryptosporidium, bacteria, and viruses

being found in well water. Several waterborne-disease

outbreaks associated with groundwater have been

reported outside California. Some of these outbreaks

are listed in Table 3-32.

Concern about pathogens in groundwater has led

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to regulatory discussions on disinfection requirements

for groundwater. EPA is currently developing a

Groundwater Disinfection Rule proposal for release

in March 1999, with a final rule by November 2000.

Data obtained through the ICR will provide information

to assess the extent and severity of risk.

The SDWA requires states to implement wellhead

protection programs designed to prevent the contamination of groundwater supplying public drinking

water wells. Wellhead protection programs rely heavily

on local efforts to be effective, because communities

have primary access to information on potential

contamination sources and can adopt locally-based

measures to manage these potential contamination

sources. EPA has recommended five steps that communities can take to implement wellhead protection:

• Form a community planning organization.

• Define the land area around the well to be protected.

• Identify potential sources of contamination within

the area.

• Develop and implement a management plan to

protect the area.

• Plan for emergencies and future water supply needs.

Water Supply Summary by

Hydrologic Region

This chapter described how the State’s water

supplies are affected by climate and hydrology, how

water supplies are calculated, and how water supplies

are reallocated through storage and conveyance

facilities and through water transfers. Also, this chapter

discussed water quality considerations that affect

beneficial uses of California’s water supplies.

Table 3-33 summarizes average year water supplies

by hydrologic region assuming 1995 and 2020

levels of development and existing facilities and programs.

Similarly, Table 3-34 summarizes drought year water

supplies by hydrologic region for existing and future

levels of development. Regional water supplies, along

with water demands presented in the following chapter,

provide the basis for the statewide water budget

developed in Chapter 6 and regional water budgets

developed in Chapters 7-9.

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WATER SUPPLIES

TABLE 3-33

California Average Year Water Supplies by Hydrologic Region (with existing facilities and program

1995 2020

Region Surface Groundwatera Recycled & Total Surface Groundwatera Re

Desalted (rounded) D

North Coast 20,331 263 13 20,610 20,371 288 

San Francisco Bay 7,011 68 35 7,110 7,067 72 Central Coast 318 1,045 18 1,380 368 1,041 South Coast 3,839 1,177 207 5,220 3,625 1,243 

Sacramento River 11,881 2,672 0 14,550 12,196 2,636 

San Joaquin River 8,562 2,195 0 10,760 8,458 2,295 Tulare Lake 7,888 4,340 0 12,230 7,791 4,386 North Lahontan 777 157 8 940 759 183 

South Lahontan 322 239 27 590 437 248 

Colorado River 4,154 337 15 4,510 3,920 285 Total (rounded) 65,090 12,490 320 77,900 64,990 12,680 

a Excludes groundwater overdraft.

TABLE 3-34

California Drought Year Water Supplies by Hydrologic Region (with existing facilities and program

1995 2020

Region Surface Groundwatera Recycled & Total Surface Groundwatera Re

Desalted (rounded) D

North Coast 10,183 294 14 10,490 10,212 321 

San Francisco Bay 5,285 92 35 5,410 5,417 89 Central Coast 160 1,142 26 1,330 180 1,159 South Coast 3,196 1,371 207 4,780 3,130 1,462 Sacramento River 10,022 3,218 0 13,240 10,012 3,281 

San Joaquin River 6,043 2,900 0 8,940 5,986 2,912 

Tulare Lake 3,693 5,970 0 9,660 3,593 5,999 

North Lahontan 557 187 8 750 557 208 

South Lahontan 259 273 27 560 326 296 

Colorado River 4,128 337 15 4,480 3,909 284 Total (rounded) 43,530 15,780 330 59,640 43,320 16,010 

a Excludes groundwater overdraft.

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4-1 WATER USE

The California Water Plan Update BULLETIN 160-98

Urban, Agricultural, and

Environmental Water Use

This chapter describes present and forecasted urban, agricultural, and environmental

water use. The chapter is organized into three major sections, one for each

category of water use.

Water use information is presented at the hydrologic region level of detail under normalized

hydrologic conditions. Forecasted 2020-level urban and agricultural water use have not changed

greatly since publication of Bulletin 160-93. Forecasted urban water use depends heavily on

population forecasts. Although the DOF has updated its California population projections since

the last Bulletin, U.S. census data are an important foundation for the projections, and a new census

will not be performed until 2000. The Department’s forecasts of agricultural water use change

relatively slowly in the short-term because the corresponding changes in forecasted agricultural acreage are a small percentage of the State’s total irrigated acreage. Changes

in base year and forecasted environmental water use from the last Bulletin reflect implementation of SWRCB’s Order WR 95-6 for the Bay-Delta.

Nursery products are

California’s third

largest farm product

in gross value. The

nursery industry is

affected by the

availability of both

agricultural and

urban water supplies.

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The California Water Plan Update BULLETIN 160-98

Water Use Calculation

The urban, agricultural, and environmental water uses calculated in this chapter are combined with

water supply information (Chapter 3) to form statewide balances (Chapter 6) and regional balances

(Chapters 7-9). As noted in the Chapter 3 discussion

of water supplies, Bulletin 160-98 water balances are

computed with applied water data, instead of the net

water data used in previous editions of the Bulletin.

Figure 4-1 shows statewide water use in terms of

applied water and depletions. The two methods provide similar results at a statewide level. (The large

depletion associated with environmental water use reflects the magnitude of wild and scenic river outflow

to the Pacific Ocean, as discussed later in the chapter.)

For purposes of presentation in the Bulletin, urban, agricultural, and environmental water uses are

treated separately. In reality, these uses are usually linked

by California’s hydrologic system. As discussed in

Chapter 3, the return flow from one water user often

becomes the supply for a downstream user. The applied water budgets used in Bulletin 160-98 reflect the

multiple uses of water in a river basin. Water supplies

in a river basin may count toward meeting wild and

scenic river use in the Sierra Nevada foothills, count

toward urban and/or agricultural uses on the Central

Valley floor, and count toward meeting Bay-Delta outflow farther downstream.

Another change from Bulletin 160-93 was

eliminating the “other” water use category to simplify

information presentation. This category included major canal conveyance losses, recreation use, cooling

water use, energy recovery use, and use by high water

using industries. Water uses previously categorized as

“other” are now included in urban, agricultural, or environmental water use, according to their intended

purpose. At a statewide level, the magnitude of these

other uses is small in comparison to that of the major

categories.

Land Use Considerations

It is important to understand how urban, agricultural, and environmental water use are shaped by land

use patterns and land use planning. Patterns of future

development and water use trends are dictated by city

and county land use planning decisions. Urbanization

of agricultural lands, open space preservation, habitat

creation, and wetlands preservation policies are examples of land use-related decisions that have water

use implications.

DOF forecasts that California’s population will increase by more than 15 million people by 2020. Where

these additional people live affects statewide urban

water use. For example, in terms of percent population increase, DOF forecasts that the City and County

of San Francisco will have one of the slowest growth

rates statewide. Adjoining Bay Area counties are also

forecasted to grow slowly, reflecting the region’s intensive urbanization and relatively small amounts of

remaining undeveloped land. Areas expected to experience high growth rates include some San Joaquin

Valley counties and the Inland Empire region in SouthSummary of Key Statistics

Shown below for quick reference are some key statistics presented in this chapter. Water use information values shown

are for applied water use in average water year conditions. The details behind the statistics are discussed later.

1995 2020 Change

Population (million) 32.1 47.5 +15.4

Irrigated crops (million acres) 9.5 9.2 -0.3

Urban water use (maf) 8.8 12.0 +3.2

Agricultural water use (maf) 33.8 31.5 -2.3

Environmental water use (maf) 36.9 37.0 +0.1

Percent of total

Urban water use (%) 11 15 +4

Agricultural water use (%) 43 39 -4

Environmental water use (%) 46 46 0

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4-3 WATER USE

The California Water Plan Update BULLETIN 160-98

Future land use patterns are important in forecasting future water use. How and where presently undeveloped lands are

developed—or are preserved from development—affects water use calculations.

1995 APPLIED WATER 2020

Agricultural

Environmental

Urban

11%

43%

46% Agricultural

Environmental

Urban

15%

39%

46%

1995 DEPLETION 2020

Agricultural

Environmental

Urban

11%

43%

46% Agricultural

Environmental

Urban

15%

40%

45%

FIGURE 4-1

California Applied Water Use and Depletion

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WATER USE 4-4

The California Water Plan Update BULLETIN 160-98

capita water use estimates at a statewide level of detail.

An urban water agency making estimates for its own

service area would be able to incorporate more complexity in its forecasting because the scope of its effort

is narrow. For this reason, and because DOF population projections seldom exactly match population

projections prepared by cities and counties, the

Bulletin’s water use forecasts are expected to be representative of, rather than identical to, those of local water

agencies.

Population Growth

Data about California’s population—its geographic distribution and projections of future

population and their distribution—come from several

sources. The Department works with base year and

projected year population information developed by

DOF for each county in the State. The decadal census

is a major benchmark for population projections. DOF

works from census data to calculate the State’s population in noncensus years, and to project future

populations. Figure 4-2 shows DOF’s projected growth

rates by county for year 2020. (State policy requires

that all State agencies use DOF population projections

for planning, funding, and policy making activities.)

DOF uses as its starting population the 1990 census, modified by the Bureau of the Census for known

misreporting. (These counts represent a modification

to the age distribution of the census count and not an

adjustment for undercount to the total.) Between 1950

and 1980 the birthrate in California mirrored the

nation’s. A sharp divergence began during the 1980s;

the nation’s birthrate was flat while the birthrate in

California rose sharply.

California’s annual growth rate was 2 to 3 percent

throughout the 1980s. After 1990, the rate slowed to

1.3 percent and the State’s population grew by only 2

million, for a 1995 population of 32.1 million.

California’s growth since 1992 has also been affected

by lower than projected natural increase (births minus

deaths) and net migration. Domestic migration patterns tend to parallel the unemployment differential

rate between California and other states. Between 1990

and 1994, California lost more than 700,000 jobs due

to the economic recession. This job loss resulted in a

new demographic phenomenon for California—a net

migration of California residents to other states. By

1996, California had replaced the jobs lost during the

recession.

Migration is the most volatile component of

ern California. This population shift to warmer, drier

inland areas where urban outdoor water use is higher

affects future statewide water demands.

The location of urban development also affects

agricultural water use. For example, subdivisions constructed on non-irrigated grazing lands do not directly

displace agricultural use (although they may compete

with existing agricultural water users for a supply).

Subdivisions constructed on irrigated farmland result

in direct conversion of water use from agricultural to

urban. Bulletin 160-98 forecasts a statewide decline

in irrigated acreage by 2020. Most of that decline is

the result of expected urbanization of irrigated agricultural lands, especially in the San Joaquin Valley and

South Coast areas. (To some extent, urbanization may

shift agricultural development to presently undeveloped lands, but such lands are usually of lower quality

and can economically support only limited crop types.)

Local open space preservation goals can affect the extent of land use conversion. Williamson Act contracts

are a commonly used means of encouraging preservation of agricultural land use, especially for agricultural

lands near urban areas. Not all open space preservation goals affect water use. For example, some land

use planning agencies in urban areas have set aside

ridgetop areas as lands to be managed for recreation

or open space to preserve viewsheds. If the areas set

aside are non-irrigated grazing lands, water use impacts are minimal.

Policies to preserve and enhance wetlands can

entail creating new wetlands or providing increased

water supplies to existing wetlands, thus increasing

environmental water use, often by conversion of agricultural water supplies. Programs creating new wildlife

habitat areas would entail conversion of agricultural

lands and water supplies to environmental uses.

Urban Water Use

Forecasts of urban water use for the Bulletin are

based on population information and per capita water use estimates, as described later in this section.

Factors influencing per capita water use include expected demand reduction due to implementation of

water conservation programs. The Department has

modeled effects of conservation measures and socioeconomic changes on per capita use in 20 major water

service areas to estimate future changes in per capita

use by hydrologic region.

The Department’s Bulletin 160 series makes per

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4-5 WATER USE

The California Water Plan Update BULLETIN 160-98

FIGURE 4-2

Projected Growth Rates by County, 1995-2020

0 - 20%

20 - 40%

40 - 60%

60 - 80%

80 - 100%

Over 100%

Legend Legend

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WATER USE 4-6

The California Water Plan Update BULLETIN 160-98

population change. Migrants are separated into two

categories: domestic (from other states) or foreign (from

other countries). Since 1980, approximately 30 percent of net migration has been domestic and 70 percent

foreign. DOF attributes fluctuations in migration primarily to domestic migration, since undocumented

migration has been fairly constant and legal foreign

migration has slowly increased. Figure 4-3 shows natural increase and net migration for the years 1940-95.

DOF uses a baseline cohort-component method

to project population by gender, race/ethnicity, and

age. A baseline projection assumes people have the right

to migrate where they choose and no major natural

catastrophes or wars will occur. A cohort-component

method traces people born in a given year throughout

their lives. As each year passes, cohorts change due to

mortality and migration assumptions. New cohorts are

formed by applying birthrate assumptions to women

of childbearing age. Special populations display different demographic behavior and other characteristics

and must be projected separately. The primary sources

of special populations are prisons, colleges, and military installations.

Population projections used in Bulletin 160-98 are

based on DOF’s Interim County Population Projections

(April 1997). Table 4-1 shows the 1995 through 2020

population figures for Bulletin 160-98 by hydrologic

Urban water demand forecasts are driven by the expected

increase in California’s population—more than 15 million

new residents by 2020. Multipurpose reservoirs help meet

needs for water-based recreational opportunities, especially

in arid Southern California.

-200

0

200

400

600

800

1000

1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

Components of Population Growth, 1940-1995

FIGURE 4-3

A n n u a l P o p u l a t i o n C h a n g e i n T h o u s a n d s

Net Migration and

Natural Increase

Net Migration

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4-7 WATER USE

The California Water Plan Update BULLETIN 160-98

region. DOF periodically updates its population forecasts to respond to changing conditions. Its 2020

population forecast used for Bulletin 160-93 was 1.4

million higher than the 2020 forecast used in Bulletin

160-98. The latter forecast incorporated the effects of

the recession of the early 1990s. Small fluctuations in

the forecast do not obscure the overall trend—an increase in population on the order of 50 percent.

The Department apportioned county population

data to Bulletin 160 study areas based on watershed

or water district boundaries. Factors considered in distributing the data to Bulletin 160 study areas

included population projections prepared by cities,

counties, and local councils of governments, which

typically incorporate expected future development

from city and county general plans. The local agency

projections indicate which areas within a county are

expected to experience growth and provide guidance

in allocating DOF’s projection for an entire county

into smaller Bulletin 160 study areas. Table 4-2 compares DOF interim projections with councils of

governments projections.

Factors Affecting Urban Per Capita Water Use

Urban per capita water use includes residential,

commercial, industrial, and institutional uses of water. Each of these categories can be examined at a greater

level of detail. Residential water use, for example, includes interior and exterior (e.g., landscaping) water

use. Forecasts of urban water use for an individual community may be separated into components and

forecasted individually. It is not possible to use this

level of detail for each community in the State in Bulletin 160-98. Bulletin 160-98 modeled components

of urban use for representative urban water agencies

in each of the State’s ten hydrologic regions and extrapolated those results to the remainder of each

hydrologic region, as described later in the chapter.

Demand reduction achieved by implementing

water conservation measures is important in forecasting per capita water use. Bulletin 160-98 incorporates

demand reductions from implementation of urban best

management practices contained in the 1991 Memorandum of Understanding Regarding Urban Water

Conservation in California. Bulletin 160-98 assumes

implementation of the urban MOU’s BMPs by 2020,

resulting in a demand reduction of about 1.5 maf over

the year 2020 demand forecast without BMP implementation. The following subsections detail existing

urban water conservation programs and estimated demand reductions. For simplicity of presentation,

conservation plans required of USBR water contractors are described in the agricultural water conservation

section, since agricultural water supply comprises the

majority of CVP water contracts. USBR’s urban water

contractors are also required to comply with these requirements.

The relationship of water pricing to water consumption, and the role of pricing in achieving water

conservation, has been a subject of discussion in recent years. Elected board members of public water

TABLE 4-2

Comparison Between Department of Finance and Councils of Governments Population Projections

(in thousands)

1990 Census 2010 Projectionsa

DOF COG

Southern California Counties 17,139 23,352 24,038

Bay Area Counties 6,020 7,489 7,540

Central Coast Counties 1,172 1,508 1,518

Greater Sacramento Counties 1,684 2,542 2,586

San Joaquin Valley Counties 2,742 4,608 4,641

a

 COG data were only available for 2010, thus 2010 COG forecasts are compared with DOF 2010 forecasts.

TABLE 4-1

California Population by Hydrologic Region

(in thousands)

Region 1995 2020

North Coast 606 835

San Francisco Bay 5,780 7,025

Central Coast 1,347 1,946

South Coast 17,299 24,327

Sacramento River 2,372 3,813

San Joaquin River 1,592 3,025

Tulare Lake 1,738 3,296

North Lahontan 84 125

South Lahontan 713 2,019

Colorado River 533 1,096

Total (rounded) 32,060 47,510

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WATER USE 4-8

The California Water Plan Update BULLETIN 160-98

agencies ultimately have the responsibility for balancing desires to achieve demand reduction through water

pricing with desires to provide affordable water rates

to consumers. Urban water rates in California vary

widely and are affected by factors such as geographic

location, source of supply, and type of water treatment

provided. Water rates are set by local agencies to recover costs of providing water service and are highly

site-specific. Appendix 4A provides background information on urban water pricing. As described in the

appendix’s summary of price elasticity studies for urban water use, residential water demand is inelastic in

most cases—water users were relatively insensitive to

changes in price, for the price ranges evaluated. Water

price plays a small role in relation to other factors affecting water use, such as public education and

plumbing retrofit programs.

Urban Water Conservation Actions. State and

federal legislation imposed standards to improve the

water use efficiency of plumbing fixtures, requiring that

fixtures manufactured, sold, or installed after specified dates meet the targets shown in Table 4-3. These

requirements apply to new construction or to retrofitting existing plumbing fixtures, but do not require

removal and replacement of existing fixtures. One water conservation action being taken by urban water

agencies is to sponsor programs for voluntary retrofitting of fixtures, to accelerate demand reductions. (This

action is one of the BMPs included in the urban

MOU.) Some water purveyors, such as the City and

County of San Francisco, have regulations requiring

retrofit when homes are sold.

More than 200 urban water suppliers have signed

the urban MOU and are now members of the California Urban Water Conservation Council. Some key

points from the MOU are highlighted in the sidebar.

Water suppliers signing the urban MOU committed

to implement BMPs unless a cost-benefit analysis conducted according to CUWCC guidelines showed

individual BMPs not to be cost-effective, or unless there

was a legal barrier to implementation. The MOU also

committed CUWCC to study measures that could be

added as new BMPs, such as establishing efficiency

standards for water-using appliances.

The urban use forecasts in Bulletin 160-98 assume

that water users statewide will implement BMPs by

2020, as set forth in Exhibit 1 of the MOU, whether

or not the BMPs are cost-effective from a water supply

standpoint. In making this assumption, the Bulletin

recognizes that water conservation measures have potential benefits in addition to water supply, such as

reduced water and wastewater treatment costs, other

water quality improvements, reduced entrainment of

fish at urban points of diversion, and greater control

of temperature and timing of wastewater discharges.

The Department believes this assumption is reasonable, given that funding sources for non-water supply

benefits could help support BMP implementation, and

that the planning horizon over which the Bulletin assumes that BMPs would be implemented (from 1995

to 2020) provides more time for implementation than

does the MOU. The widespread acceptance that the

existing BMPs have achieved, as evidenced by the number of MOU signatories, indicates that the BMPs are

generally considered to be technologically feasible, so

technology should not be a limiting factor in implementation.

Quantifying demand reduction from implementation of some BMPs is difficult (for example, public

information programs and water education in schools).

These actions contribute to implementation of other

BMPs, such as demand reduction from installing water meters, but do not by themselves save quantifiable

amounts of water. CUWCC reviewed implementation

Landscape Water Use

The Model Water Efficient Landscape Ordinance was

added to Title 23 of the California Code of Regulations in

response to requirements of the 1990 Water Conservation in

Landscaping Act. Local agencies that did not adopt their own

ordinances by January 1993 were required to begin

enforcement of the model ordinance as of that date.

The model ordinance applies to all new and rehabilitated

landscaping (more than 2,500 square feet in size) for public

agency projects and private development projects that require

a local agency permit, and to developer-installed landscaping

for single-family and multifamily residential projects. The

purpose of the ordinance was to promote water efficient

landscape design, installation, and maintenance. The general

approach of the ordinance was to use 0.8 ET0

 as a water use

goal for new and renovated landscapes. (ET0

 is a reference

evapotranspiration, established according to specific criteria.)

Tools to help meet that goal include proper landscape and

irrigation system design.

To date, there has been no statewide-level review of how

cities and counties are implementing this requirement; thus,

its water savings potential remains to be quantified.

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The California Water Plan Update BULLETIN 160-98

TABLE 4-3

Summary of California and Federal Plumbing Fixture Requirements

Energy

California Policy Act of 1992

Plumbing Device (covers sale and Effective Date (covers only

installation) manufacture)

Showerheads 2.5 gpm CA 3/20/92

US 1/1/94 2.5 gpm

Lavatory Faucetsa 2.75 gpm CA 12/22/78

2.2 gpm CA 3/20/92

US 1/1/94 2.5 gpm

Sink Faucetsa 2.2 gpm CA 3/20/92

US 1/1/94 2.5 gpm

Metering (self-closing) hot water maximum CA 7/1/92

 Faucetsb flow rates range from US 1/1/94 0.25 gallons/cycle

(public restrooms) 0.25 to 0.75 gallons/ (maximum water

cycle and/or from 0.5 delivery per cycle)

gpm to 2.5 gpm,

depending on controls

and hot water system

Tub Spout Divertera 0.1 (new), to 0.3 gpm CA 3/20/92 (does not appear to be

(after 15,000 cycles included in EPA)

of diverting)

Toilets 1.6 gpf CA 1/1/92 (new

(residential) construction)

CA 1/1/94 (all toilets for

sale or installation)

US 1/1/94 (non- 1.6 gpf

commercial)

Flushometer valvesa 1.6 gpf CA 1/1/92 (new

construction)

CA 1/1/94 (all toilets)

US 1/1/94 (commercial) 3.5 gpf

US 1/1/97 (commercial) 1.6 gpf

Toilets 1.6 gpf CA 1/1/94 (all toilets for

(Commercial)a sale or installation)

US 1/1/97 1.6 gpf

Urinals 1.0 gpf CA 1/1/92 (new)

CA 1/1/94 (all)

US 1/1/94 1.0 gpf

a California requirements are preexisting and more stringent than federal law; therefore California requirements prevail in California.

b Federal law is more stringent than California requirements.

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WATER USE 4-10

The California Water Plan Update BULLETIN 160-98

and quantification of the initial BMPs, and developed

a strategic plan in 1996 that included evaluating the

BMPs and revising them to make them easier to quantify. The revised BMPs (see sidebar) were adopted by

CUWCC in September 1997. The revisions included

restructuring the original 16 BMPs to 14 BMPs (new

BMPs were also added—rebate programs for high efficiency washing machines and wholesale water agency

assistance to retail water agencies), revising implementation schedules and coverage requirements, and adding

new evaluation criteria. Implementation of some BMPs

was extended beyond the original 10-year term of the

existing MOU. Appendix 4B presents a synopsis of

the revisions.

Local agencies were required by the 1990 Water Conservation in Landscaping Act to enforce ordinances intended to promote

water-efficient designs. The act’s requirements apply to landscapes greater than 2,500 sq. ft. in size.

Urban Best Management Practices (1997 Revision)

BMP 1 Water Audit Programs for Single-Family Residential and Multifamily Residential Customers

BMP 2 Residential Plumbing Retrofit

BMP 3 System Water Audits, Leak Detection and Repair

BMP 4 Metering With Commodity Rates for All New Connections and Retrofit of Existing Connections

BMP 5 Large Landscape Conservation Programs and Incentives

BMP 6 High-Efficiency Washing Machine Rebate Programs (New)

BMP 7 Public Information Programs

BMP 8 School Education Programs

BMP 9 Conservation Programs for Commercial, Industrial, and Institutional Accounts

BMP 10 Wholesale Agency Assistance Programs (New)

BMP 11 Conservation Pricing

BMP 12 Conservation Coordinator (Formerly BMP 14)

BMP 13 Water Waste Prohibition

BMP 14 Residential ULFT Replacement Programs (Formerly BMP 16)

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4-11 WATER USE

The California Water Plan Update BULLETIN 160-98

Bulletin 160-98 estimates water savings due to

BMP implementation based on the assumptions set

forth in Exhibit 1 of the urban MOU, and assumes

that California will achieve a level of water conservation equivalent to that expected from full BMP

implementation by 2020. The MOU specifies implementation schedules, water use reduction factors, and

installation and/or compliance rates that allow quantification of water savings for 7 of the 14 BMPs. The

MOU identifies the remaining BMPs as not having

quantifiable water savings. The Bulletin’s estimated

water savings (Appendix 4B) are based on evaluation

of the following BMPs in accordance with the Exhibit

1 provisions: residential water use surveys, residential

plumbing retrofits, distribution system water audits/

leak detection/repairs, metering with commodity rates,

programs for commercial/industrial/institutional accounts, and residential ultra-low flush toilet

replacement. Water savings for the BMP on large landscape water conservation (3 acres or greater) could not

be evaluated due to lack of data on existing irrigated

landscape acreage.

BMP implementation is estimated to result in a

statewide 2020 demand reduction of 1.5 maf statewide. As discussed in Chapter 6, this demand reduction

is not the same as creating new water supply. Only

conservation actions that reduce irrecoverable losses

or reduce depletions actually create new water supply

from a statewide perspective. Table 4-4 shows applied

water and depletion reductions due to BMP implementation by hydrologic region.

As more water conservation measures are implemented, especially structural changes such as plumbing

retrofits, it will become increasingly difficult for urban water agencies and their customers to achieve

drought year demand reductions. Demand hardening

is discussed in more detail in Chapter 6. The urban

MOU acknowledges that demand hardening will be a

Highlights of the Urban MOU

Shown below are several excerpts from the urban

MOU that are relevant to the water conservation measures

discussed in Chapters 4 and 6.

Recital F It is the intent of this MOU that individual

signatory water suppliers (1) develop comprehensive conservation

BMP programs using sound economic criteria and (2) consider

water conservation on an equal basis with other water

management options.

Recital G It is recognized that present urban water use

throughout the State varies according to many factors including,

but not limited to, climate, types of housing and landscaping,

amounts and kinds of commercial, industrial and recreational

development, and the extent to which conservation measures have

already been implemented. It is further recognized that many of

the BMPs identified in Exhibit 1 to this MOU have already

been implemented in some areas and that even with broader

employment of BMPs, future urban water use will continue to

vary from area to area. Therefore, this MOU is not intended to

establish uniform per capita water use allotments throughout

the urban areas of the State. This MOU is also not intended to

limit the amount or types of conservation a water supplier can

pursue or to limit a water supplier’s more rapid implementation

of BMPs.

Section 4.1 (c) Assumptions for use in developing estimates of

reliable savings from the implementation of BMPs. Estimates of

reliable savings are the water conservation savings which can be

achieved with a high degree of confidence in a given service area.

The estimate of reliable savings for each BMP depends upon the

nature of the BMP and upon the amount of data available to

evaluate potential savings. For some BMPs (e.g., public

information) estimates of reliable savings may never be generated.

For others, additional data may lead to significant changes in

the estimate of reliable savings. It is probable that average savings

achieved by water suppliers will exceed the estimates of reliable

savings.

Section 4.5 Exemptions. A signatory water supplier will be

exempt from the implementation of specific BMPs for as long as

the supplier substantiates each reporting period that, based upon

then prevailing local conditions, one or more of the following

findings applies: (a) A full cost-benefit analysis, performed in

accordance with the principles set forth in Exhibit 3, demonstrates

that either the program (i) would not be cost-effective overall

when total program benefits and costs are considered; OR (ii)

would not be cost-effective to the individual water supplier even

after the water supplier has made a good faith effort to share costs

with other program beneficiaries.

(b) Adequate funds are not and cannot reasonably be made

available from sources accessible to the water supplier including

funds from other entities. However, this exemption cannot be

used if a new, less cost-effective water management option would

be implemented instead of the BMP for which the water supplier

is seeking this exemption.

(c) Implementation of the BMP is (i) not within the legal

authority of the water supplier; and (ii) the water supplier has

made a good faith effort to work with other entities that have the

legal authority to carry out the BMP; and (iii) the water supplier

has made a good faith effort to work with other relevant entities

to encourage the removal of institutional barriers to the

implementation of BMPs within its service area.

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WATER USE 4-12

The California Water Plan Update BULLETIN 160-98

consequence of BMP implementation.

Although there are other urban water conservation programs besides those associated with the urban

MOU, only the MOU presently addresses quantification of water savings. EPA has started developing water

conservation guidelines pursuant to Section 1455 of

the 1996 SDWA. USBR has developed guidelines for

Reclamation Reform Act water conservation plans and

for the more detailed conservation plans required by

CVPIA. The USBR conservation plans apply to both

urban and agricultural contractors, and are

described in more detail in a later section on agricultural water conservation.

Effects of Droughts on Urban Water Production. To illustrate the effects of droughts, Figure 4-4

shows statewide per capita urban water production over

time. (Per capita production is the water provided by

urban suppliers, divided by population. Urban water

production is not the same as total urban water use;

total use includes self-produced supplies, water for recreation and energy production uses, and losses from

major conveyance facilities.) After the severe, but brief,

1976-77 drought, statewide urban per capita water production rates returned to pre-drought levels within 3

to 4 years. During the longer 1987-92 drought, urban

per capita water production rates declined by about

19 percent on the average statewide. (Most requirements for water-conserving plumbing fixtures did not

take effect until after the 1987-92 drought.) The

Department’s data show increases in per capita water

production following the drought, due to removal of

mandatory water rationing and other short-term restrictions. When viewed at a statewide level, the data

show a strong response to hydrologic conditions.

 Urban Water Use Planning Activities

The Department has surveyed retail water agencies and analyzed their water production data for more

than 35 years, publishing the data in the Bulletin 166

series, Urban Water Use in California. Bulletin 166-4,

published in 1994, summarized monthly urban water

production data from 1980-90 for nearly 300 retail

water purveyors throughout the State. This water use

information, updated in the Department’s annual surveys, is a primary data source for water use estimates

made for Bulletin 160. The Department also conducted a statewide survey of industrial water use by

water-using sector in 1994. Industrial water use information is periodically published in the Department’s

Bulletin 124 series, Industrial Water Use in California.

The Urban Water Management Planning Act requires that urban water suppliers with 3,000 or more

connections, or that deliver over

3 taf of water per year, prepare urban water management plans and

submit them to the Department.

The initial set of plans was due

in 1985; plans are to be updated

every five years. Table 4-5 shows

the number of agencies affected

by the law and those submitting

their 1995 plans as of March

1997. The 1995 plans received

were from agencies representing

almost 90 percent of all urban water deliveries. These plans have

multiple purposes, including

demonstrating how local agencies

TABLE 4-4

Annual Reductions in Applied Water and

Depletions Due to BMP Implementation by

2020 (taf)

Region Applied Water Depletion

North Coast 20 11

San Francisco Bay 176 172

Central Coast 48 30

South Coast 768 500

Sacramento River 91 0

San Joaquin River 111 30

Tulare Lake 125 50

North Lahontan 5 2

South Lahontan 59 21

Colorado River 111 52

Total 1,514 868

150

200

250

1940 45 5550 60 65 70 75 80 85 90 95

Statewide Average Per Capita

Urban Water Production Over Time

FIGURE 4-4

G a l l o n s P e r C a p i t a P e r D a y

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4-13 WATER USE

The California Water Plan Update BULLETIN 160-98

propose to implement water conservation measures and

how the agencies plan to meet drought year water supply reliability goals.

The CALFED Bay-Delta program includes water

use efficiency—urban, agricultural, and environmental—as one of the common elements required for all

proposed Delta alternatives. As described in the water

use efficiency technical appendix for the March 1998

draft programmatic EIR/EIS, potential elements of an

urban water use efficiency program include:

• Requirements that urban water management plans

be implemented more vigorously and that the

Department review and certify those plans.

• Revisions to the BMPs to make them more

quantifiable.

• Requirements that CUWCC certify BMP

implementation.

• Provision of financial and technical assistance to

water agencies to encourage program implementation.

CALFED is also examining ways to require that

the urban water use efficiency program be implemented

vigorously. For example, urban water agencies that

choose not to implement the program could be excluded from participation in water transfers requiring

approval by a CALFED agency, from use of facilities

operated by a CALFED agency, from new supplies

made available by a CALFED actions, or from participating in certain loan and grant programs. In addition,

CALFED has suggested that SWRCB could be asked

to pursue its obligations to investigate waste and unreasonable use more vigorously. Methods to achieve

assurances remain under discussion. Depending on the

methods chosen, amendments to existing statutes or

execution of new agreements would be needed. Quantification of CALFED’s future water use efficiency

program is discussed in Chapter 6.

Urban Water Use Forecasting

Urban water use forecasting relates future use to

changes in factors influencing water use. Early

forecasting methods were relatively simple and relied

only on service area population to explain water use,

assuming a direct relationship between population

growth and applied water demand. These methods can

provide acceptable results over the short term, especially during periods of abundant water supply and

steady economic growth. However, mid- to long-term

forecast accuracy may decrease sharply due to changes

in other variables influencing water use. Among these

factors are changes in the ratio of single to multifamily

dwellings, commercial and industrial growth, income,

future water conservation actions, and water pricing.

The price of water currently plays a small role in water

use; it could become more important if water prices

increased substantially. The water price elasticity section in Appendix 4A provides more detail on this

subject. New urban water supplies will be relatively

expensive, so understanding interactions between price

and water use is important for forecasting urban use.

As described in the appendix, the Department’s forecast used single family residential price elasticities of

-0.1 for winter months and -0.2 for summer months.

The Department forecasted change in per capita

water use in each hydrologic region to estimate 2020

urban applied water by hydrologic region. Variables

included population, income, economic activity, water price, and conservation measures (implementation

of urban BMPs and changes to State and federal plumbing fixture standards). The general forecasting

procedure was to determine 1995 base per capita water use, estimate the effects of conservation measures

and socioeconomic change on future use for 20 major

representative water service areas in California, and

calculate 2020 base per capita water use by hydrologic

region from the results of service area forecasts.

1995 Base Per Capita Water Use. The 1995 base

per capita water use includes water supplied by public

water systems for municipal and industrial purposes

and self-produced (not delivered by a water purveyor)

surface water and groundwater. Per capita water use is

not the same as the applied water use shown in Bulletin 160 water budgets. Per capita use does not include

recreation water use, energy production water use, and

TABLE 4-5

1995 Urban Water Management Plans by

Hydrologic Region

Region Expected Filed

North Coast 13 10

San Francisco Bay 60 46

Central Coast 28 17

South Coast 187 152

Sacramento River 35 33

San Joaquin River 29 12

Tulare Lake 22 13

North Lahontan 5 2

South Lahontan 12 11

Colorado River 13 6

Total 404 302

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The California Water Plan Update BULLETIN 160-98

TABLE 4-6

Urban Water Use Study Input Variables

Water Use

Water use by sector, base year

Single family

Multifamily

Commercial

Industrial

Landscape

Seasonal water use, base year

Socioeconomic

Population, base year, and forecast year

Total population

Population by dwelling type

Persons per household by dwelling type

Group quarters population

Housing, base year, and forecast year

Number of housing units by dwelling type

Growth rate of housing stock by dwelling type

Employment, base year, and forecast year

Commercial

Industrial

Income, base year, and forecast year

Water price, base year, and forecast year

losses from major conveyance facilities (the urban share

of the “other” water demand category used in Bulletin

160-93). In most hydrologic regions, 1995 base per

capita water use was calculated for each of the

Department’s DAUs. In the South Lahontan and Colorado River regions, analyses were done at the PSA level

due to the relatively sparse populations in those regions.

The 1995 base per capita water use was computed

from normalized water use data to account for variation in annual weather patterns, water supply, and

residual effects of the 1987-92 drought. Appendix 4C

discusses the relationship between normalized data and

actual urban water production data. Actual urban water use during 1995 was less than the Bulletin 160-98

base level in many areas, largely due to wet hydrologic

conditions that decreased landscape irrigation requirements. (Likewise, urban water use during a dry year

would likely exceed base year use due to higher landscape irrigation water use, assuming no constraints on

water supplies). Base per capita 1995 water use was

developed from historical water use during recent years

with normal water supply and water use patterns. Data

for years during and immediately following the drought

were removed from consideration due to the effects of

water shortages of unprecedented severity and duration, mandatory and voluntary rationing programs,

and a multi-year post-drought rebound in per capita

water use on water use patterns. The 1995 base was

computed from the 1990 per capita use in Bulletin

160-93, adjusted to account for permanent effects of

urban BMPs and post-1990 changes to federal and

State plumbing fixture standards. The most significant

post-1990 change to the plumbing fixture standards

was that all toilets for sale or installation in California

must use no more than 1.6 gallons per flush, compared to 3.5 gallons or more per flush for older toilets.

Plumbing code effects were quantified based on the

proportion of total housing stock subject to the new

code. ULFT retrofit water savings were estimated based

on information on toilet retrofit programs from local

water agencies. The final 1995 base value for each DAU

was weighted by population to yield 1995 base per

capita water use by hydrologic region.

2020 Per Capita Water Use Forecast. Forecasts

for the urban water use study were based on three types

of input data: actual values of base year water and socioeconomic variables, forecasted values of

socioeconomic variables for the year 2020, and savings assumptions for BMPs. Table 4-6 lists the input

variables specified for each water service area. Table 4-

7 shows data sources for the study.

The urban water use study estimated future change

in per capita water use in 20 representative water service areas. (The results in Tables 4-8 and 4-9 display

changes from 1990, rather than from the Bulletin’s

1995 base year, to illustrate all effects of water conservation implementation, including the changes in

plumbing fixture standards that began in 1992.) The

results of the 20 individual model runs were extrapolated to forecast 2020 level per capita water use by

hydrologic region (Tables 4-9 and 4-10). The difference between the 1995 and 2020 base levels reflects

the influence of water conservation measures, socioeconomic change, and differential population growth

on per capita water use in each region.

The forecast results for the representative water

service areas were expressed as a percent change in per

capita use by 2020, and were averaged (weighted by

service area population) to arrive at the percent change

in per capita use by hydrologic region. For each region, the 2020 change was applied to the 1995 level

per capita water use in each DAU to obtain 2020 per

capita water use. The 2020 per capita water use then

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The California Water Plan Update BULLETIN 160-98

TABLE 4-7

Urban Water Use Study Data Sources

Water Use

Survey of Public Water System Statistics, DWR

Urban water management plans

Regional and local water agency reports on water use and conservation

Socioeconomic

Census of Population and Housing, U.S. Department of Commerce

Survey of Current Business, USDC

Statistical Abstract of the United States, USDC

California Statistical Abstract, DOF

California Population Characteristics, Center for Continuing Study of the California Economy

Population Projections by Race and Ethnicity for California and its Counties 1990-2040, DOF

Regional and local planning agencies

TABLE 4-8

Model Study Results—Per Capita Water Use With Economic

Growth and Conservation Measures

Region Representative Water 1990 2020 Percent Change from 1990

Service Area (gpcd) (gpcd) Economic Conservation

Effects Effects

North Coast City of Santa Rosa 156 136 -14 2

San Francisco Bay EBMUD 196 171 -16 3

Marin Municipal WD 153 136 -16 5

City and County of San Francisco 132 115 -16 3

Central Coast California Water Service Company, Salinas 153 132 -14 0

City of Santa Barbara 177 156 -15 4

South Coast City of Los Angeles 180 158 -16 4

City of San Bernardino 269 243 -11 1

San Diego County WA 196 176 -14 4

Sacramento River California Water Service Company, Chico 296 272 -10 2

City of Sacramento 290 263 -13 3

San Joaquin River California Water Service Company, Stockton 187 162 -12 -1

City of Merced 336 299 -10 0

Tulare Lake California Water Service Company, Visalia 273 235 -11 -3

City of Fresno 285 262 -10 2

North Lahontan South Lake Tahoe PUD 179 147 -15 -2

South Lahontan Indian Wells Valley WD 247 230 -10 3

Victor Valley County WD 340 322 -8 3

Colorado River City of Blythe 349 326 -11 4

City of El Centro 221 197 -13 2

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WATER USE 4-16

The California Water Plan Update BULLETIN 160-98

was multiplied by the population forecast to compute

2020 urban applied water use for each DAU. The

DAU-level results were aggregated and combined with

minor components of urban use (conveyance losses,

recreation water use, and energy production water use)

to obtain total applied urban water demands.

This method of computing future water use captures localized effects of differential population growth.

The most significant example of variation in growth

patterns is the relatively high growth rate in warmer,

drier inland areas of California where increased landscape irrigation requirements are reflected in higher

per capita use values. Growth in inland areas tends to

partially offset reductions in per capita use due to water conservation.

Summary of Urban Water Use

Table 4-11 summarizes Bulletin 160-98 urban

applied water use by hydrologic region. Statewide urban use at the 1995 base level is 8.8 maf in average

water years and 9.0 maf in drought years. (Drought

year demands are slightly higher because less precipitation is available to meet exterior urban water uses,

such as landscape watering.) Forecasted 2020 use increases to 12.0 maf in average years and 12.4 maf in

drought years. Full implementation of urban BMPs is

estimated to result in demand reduction of 1.5 maf in

average year water use by 2020. Without implementation of urban BMPs, average year use would have

increased to 13.5 maf.

Table 4-9

TABLE 4-9

2020 Change in Per Capita Use by Hydrologic Region—

Application of Model Resultsa

Region Economic Effects Conservation Effects

% Change from 1990 % Change from 1990

North Coast 2 -14

San Francisco Bay 3 -16

Central Coast 2 -15

South Coast 4 -14

Sacramento River 3 -12

San Joaquin River -1 -12

Tulare Lake 1 -10

North Lahontan -2 -15

South Lahontan 3 -9

Colorado River 3 -12

Statewide 3 -15

a Model results applied to per capita use in each DAU.

TABLE 4-10

Effects of Conservation on Per Capita Water Usea by Hydrologic Region

(gallons per capita per day)

Region 1995 2020

without conservation with conservation

North Coast 249 236 215

San Francisco Bay 192 188 166

Central Coast 179 188 166

South Coast 208 219 191

Sacramento River 286 286 264

San Joaquin River 310 307 274

Tulare Lake 298 302 268

North Lahontan 411 390 356

South Lahontan 282 294 268

Colorado River 564 626 535

Statewide 229 243 215

a

 Includes residential, commercial, industrial, and landscape use supplied by public water systems and self-produced surface and groundwater. Does not

include recreational use, energy production use, and losses from major conveyance facilities. These are normalized data.

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The California Water Plan Update BULLETIN 160-98

use. The table also illustrates that precipitation plays a

small role in meeting urban outdoor water needs (landscape water needs) in arid regions such as the Tulare

Lake, South Lahontan, and Colorado River regions.

Agricultural Water Use

The Department’s estimates of agricultural water

use are derived by multiplying water use requirements

for different crop types by their corresponding irrigated acreage, and summing the results to obtain a

total for irrigated crops in the State. This section begins by covering crop water use requirements, including

demand reduction from water conservation programs.

Irrigation efficiency and distribution uniformity are

discussed in detail. A description of the process for

forecasting irrigated acreage and factors affecting acreage forecasts follows. Forecasted 2020 agricultural water

demands are summarized at the end of the section.

Crop Water Use

The water requirement of a crop is directly related

to the water lost through evapotranspiration. The

amount of water that can be consumed through ET

depends in the short term on local weather and in the

long term on climatic conditions. Energy from solar

radiation is the primary factor that determines the rate

of crop ET. Also important are humidity, temperature,

wind, stage of crop growth, and the size and aerodynamic roughness of the crop canopy. Irrigation

frequency affects ET after planting and during early

growth because evaporation increases when the soil

All of the acreage amounts discussed in this chapter are

irrigated acres, because estimates of irrigated acreage are

needed to calculate agricultural water use. Crop production

also occurs (to a much lesser extent) on non-irrigated lands.

Dry-farmed grains are an example of crop production on

non-irrigated lands.

TABLE 4-11

Applied Urban Water Use by Hydrologic Region (taf)

1995 2020

Region Average Drought Average Drought

North Coast 169 177 201 212

San Francisco Bay 1,255 1,358 1,317 1,428

Central Coast 286 294 379 391

South Coast 4,340 4,382 5,519 5,612

Sacramento River 766 830 1,139 1,236

San Joaquin River 574 583 954 970

Tulare Lake 690 690 1,099 1,099

North Lahontan 39 40 50 51

South Lahontan 238 238 619 619

Colorado River 418 418 740 740

Total (rounded) 8,770 9,010 12,020 12,360

As indicated in the Table 4-11, the South Coast

and San Francisco Bay Hydrologic Regions together

amount to over half of the State’s total urban water

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WATER USE 4-18

The California Water Plan Update BULLETIN 160-98

surface is wet and is exposed to sunlight. Growing season ET varies significantly among crop types,

depending primarily on how long the crop actively

grows.

Direct measurement of crop ET requires costly

investments in time and sophisticated equipment.

There are more than 9 million acres of irrigated crop

land in California, encompassing a wide range of climate, soils, and crops. Even where annual ET for two

areas is similar, monthly totals may differ. For example,

average annual ET for Central Coast interior valleys is

similar to that in the Central Valley. Central Valley ET

is lower than that in coastal valleys during the winter

fog season and higher during the hot summers. Obtaining actual measurements for every combination of

environmental variables would be prohibitively difficult and expensive. A more practical approach is to

estimate ET using methods based on correlation of

measured ET with observed evaporation, temperature,

and other climatologic conditions. Such methods can

be used to transfer the results of measured ET to other

areas with similar climates.

The Department uses the ET/evaporation correlation method to estimate growing season ET.

Concurrent with field measurement of ET rates, the

Department developed a network of agroclimate stations to determine the relationship between measured

ET rates and pan evaporation. Data from agroclimatic

studies show that water evaporation from a standard water

surface (the Department uses the U.S. Weather Bureau

Class A evaporation pan) closely correlates to crop ET.

The ET/evaporation method estimates crop water use to

within ± 10 percent of measured seasonal ET.

Crop coefficients are applied to pan evaporation

data to estimate evapotranspiration rates for specific

crops. (Crop coefficients vary by crop, stage of crop

growth, planting and harvest dates, and growing season duration.) The resulting data, combined with

information on effective rainfall and water use efficiency, form the basis for calculating ETAW and

applied water use. Crop applied water use includes the

irrigation water required to meet crop ETAW and cultural water requirements.

The amount of water applied to a given field for

crop production is influenced by considerations such

as crop water requirements, soil characteristics, the

ability of an irrigation system to distribute water uniformly on a given field, and irrigation management

practices. In addition to ET, other crop water requirements can include water needed to leach soluble salts

below the crop root zone, water that must be applied

for frost protection or cooling, and water for seed germination. The amount required for these uses depends

upon the crop, irrigation water quality, and weather

conditions.

Part of a crop’s water requirements can be met by

rainfall. The amount of rainfall beneficially used for

crop production is called effective rainfall. Effective

rainfall is stored in the soil and is available to satisfy

crop ET or to offset water needed for special cultural

practices such as leaching of salts. Irrigation provides

the remainder of the crop water requirement. Irrigation efficiency influences the amount of applied water

needed, since a portion of each irrigation goes to system leaks and deep percolation of irrigation water

below the crop root zone.

There is a perception that

only drip irrigation is an

efficient agricultural water

use technology. As described

in Chapter 5, high

efficiencies are possible with

a variety of irrigation

techniques. Considerations

such as soil type, field

configuration, and crop type

influence the choice of

irrigation technique.

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The California Water Plan Update BULLETIN 160-98

The Bulletin’s 1995 base applied agricultural water use values were computed from normalized data to

account for variation in annual weather patterns and

water supply. Normalizing entails applying crop coefficients to long-term average evaporative demand data.

Actual applied crop water use during 1995 was less

than the Bulletin 160-98 base in many areas due to

wet hydrologic conditions that increased effective rainfall, thus decreasing crop ETAW. Likewise, applied

water use during a dry year (assuming no constraints

on water supplies) would likely exceed the base due to

less than average effective rainfall with an attendant

increase in crop ETAW. For most hydrologic regions,

1995 base applied water use was computed for the major crop types found in each of the Department’s

DAUs. Analyses were done at the planning subarea

level in the South Lahontan and Colorado River Regions.

Figure 4-5 shows ranges of 1995 base applied water and ETAW for some common California crops or

crop types. ETAW represents a major depletion of water

supply, and therefore is an important component of

statewide and local water supply planning, groundwater modeling, and water transfer feasibility studies.

Except in areas adjacent to the ocean, or areas where

the groundwater or surface water is unacceptable for

reapplication, irrigation water applied in excess of ET

and cultural requirements (e.g., frost protection) is

available to downstream users or to users pumping from

groundwater.

The purpose of the data presented in Figure 4-5 is

to illustrate how great the range of applied water and

ETAW can be for a single crop or crop type in California. Climate and soil types are major factors that affect

crop water use. Other factors include farming practices, irrigation systems, and water availability. Crop

water use is extremely site-specific, and no one value

of crop water use can be expected to represent a statewide condition.

Factors Influencing Agricultural Water Use

Irrigation Water Use Efficiency. Distribution

uniformity is an important element in on-farm irrigation water use efficiencies. DU measures the variation

in the amount of water applied to the soil throughout

the irrigated area. Since no irrigation system is capable

of applying and distributing water uniformly to all parts

of a field, growers often apply enough water to meet

crop water requirements of the driest part of the field

to achieve optimum crop yields. Achieving a high DU

requires excellent system design, maintenance, and

management. Irrigation experts maintain that current

hardware design and manufacturing technology limit

the DU of most systems to 80 percent. As design and

manufacturing technology advance and more refined

manufacturing processes and hardware are developed,

it may be possible to achieve DUs up to 90 percent.

Chapter 5 describes the relationship of DU to irrigation efficiencies in more detail.

Seasonal application efficiency is the sum of ETAW

and cultural water requirements (such as for leaching

salts below the root zone) divided by applied water.

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The California Water Plan Update BULLETIN 160-98

SAE is an appropriate index of water use efficiency for

planning purposes, because it is based on the amount

of water required to fully satisfy crop water needs while

maintaining the favorable salt balance in the root zone

required for long-term sustainability of agriculture. It

differs from values of irrigation efficiency calculated

by growers to compare the amount of water beneficially used to the amount applied, because the amount

beneficially used may be less than that needed to fully

satisfy crop and cultural water requirements. Efficiency

measures used by growers, such as DU and IE, are typically based on the average amount of water

infiltrating the quarter of the field receiving the least

water. These methods presume that one-half of the low

quarter, or 12.5 percent of the field, is under-irrigated

to some degree. The result is inadequate leaching and

a reduction in crop yield in that part of the field.

Values of SAE cannot be directly compared to IE

values commonly cited in literature because they are

based on different levels of irrigation effectiveness.

Optimal SAE occurs when the driest part of the field

receives an amount of water equal to ETAW plus leaching water requirements, resulting in a 100 percent

effective irrigation. On the other hand, optimal IE occurs when the amount infiltrated in the low quarter

equals ETAW plus leaching requirements, resulting in

an 87.5 percent effective irrigation. (Since DU is also

calculated based on the low-quarter method, optimal

IE is equivalent to DU.) SAE is related to DU and to

optimal IE by a linear function so that, for example, a

DU of 75 percent implies an optimal SAE of 67 percent. The relationship among DU and optimal values

of IE and SAE is illustrated in Table 4-12. The maximum efficiency values achieved on-farm are generally

less than shown due to conveyance losses, evaporation,

and uncollected surface runoff.

Relationships between on-farm and regional

efficiencies are complex. Often a portion of irrigation

water applied to a field runs off the field or percolates

into groundwater. Runoff and/or deep percolation

from a given field may be considered a water loss to

that particular field; nevertheless, this water is not lost

to the system unless it goes directly to a nonreusable

water source such as saline groundwater or to the ocean.

If water quality is good, that water may be reapplied

on a field or on other fields several times. Irrigation

efficiency formulas developed for on-farm irrigation

management cannot necessarily be applied to larger

areas or regions. Numerical values of on-farm and regional efficiencies almost always differ. On-farm

TABLE 4-12

Relationship Among Agricultural Water Use

Efficiency Measures

Distribution Irrigation Seasonal Application

Uniformity Efficiencya Efficiencya

90 90 87

85 85 80

80 80 73

75 75 67

70 70 60

a

 Optimal values

Efficient Water Management Practices for

Agricultural Water Suppliers in California

List A—Generally Applicable EWMPs

• Prepare and adopt a water management plan

• Designate a water conservation coordinator

• Support the availability of water management services

to water users

• Improve communication and cooperation among water

suppliers, water users, and other agencies

• Evaluate the need, if any, for changes in institutional

policies to which the water supplier is subject

• Evaluate and improve efficiencies of the water supplier’s

pumps

List B—Conditionally Applicable EWMPs

• Facilitate alternative land use

• Facilitate using available recycled water that otherwise

would not be used beneficially, meets all health and safety

criteria, and does not cause harm to crops or soil

• Facilitate financing capital improvements for on-farm

irrigation systems

• Facilitate voluntary water transfers that do not

unreasonably affect the water user, water

supplier, the environment, or third parties

• Line or pipe ditches and canals

• Increase flexibility in water ordering by, and delivery to,

water users within operational limits

• Construct and operate water supplier spill and tailwater

recovery systems

• Optimize conjunctive use of surface and groundwater

• Automate canal structures

List C—Other EWMPs

• Water measurement and water use reporting

• Pricing or other incentives

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The California Water Plan Update BULLETIN 160-98

efficiencies are usually lower than regional efficiencies

due to reapplication of water in a region. A region can

reach very high efficiencies as a result of a few reapplications, even if on-farm efficiencies are fairly low.

Practices that encourage reapplication, such as tailwater

return and spill recovery systems, provide an opportunity to increase regional efficiency. Water reapplication

can be the fastest and most economical way to boost

regional efficiencies.

Agricultural Water Conservation Programs. The

amount of applied water saved depends on the actions

of both water suppliers and irrigation water users.

Achieving high on-farm water use efficiency is accomplished by optimizing many factors including

management (such as irrigation scheduling), irrigation

method, crop selection, and supply reliability. On-farm

evaluations conducted by the Department and others

show that irrigation management is more important

than irrigation method in improving water use efficiency. (Chapter 5 describes common irrigation

methods.)

Bulletin 160-98 quantifies agricultural water conservation based on assumed statewide implementation

of the 1996 agricultural MOU described in Chapter

2. The agricultural MOU provides a mechanism for

planning and implementing EWMPs (see sidebar) that

benefit water suppliers. The primary objective of

EWMPs is for suppliers to better serve farmers in order to facilitate improvements in on-farm practices.

As of May 1998, 31 agricultural water agencies serving about 3 million acres of land had signed the MOU.

Signatories to the MOU have committed to implement specified EWMPs, based on their evaluation of

the benefits of each practice.

EWMPs can lessen runoff and deep percolation

of irrigation water, reducing the amount of water farmers must order from an irrigation district or pump from

their wells. Because the MOU is orientated to water

suppliers, it does not specify water use reduction factors and installation and/or compliance rates for farm

irrigation system improvements. Therefore, the Department estimated water savings due to EWMPs based

on their potential to remove impediments to optimal

on-farm efficiency, expressed as increased SAE. SAE

resolves the interrelated effects of EWMPs and improved on-farm management into one variable that

quantifies the net result of water conservation efforts

by water suppliers and irrigation water users. It is expected that increasing use of EWMPs will yield more

information on their water savings potential.

Water savings due to agricultural water conservation were quantified for each DAU on the basis of

expected improvements in SAE. It is assumed that by

2020 SAE will reach 73 percent in all regions of California, averaged across crop types, farmland

characteristics, and management practices. The DU

of irrigation methods limits SAE. The average DU of

irrigation systems in California is currently in the 70

to 75 percent range, based on irrigation system evaluations conducted by the Department, resource

conservation districts, water districts, and others. By

2020, the average DU is expected to be about 80 percent. An irrigation method with a DU of 80 percent

can achieve a maximum SAE of about 73 percent, assuming that irrigation events are properly timed, the

soil is well drained, and none of the field is underirrigated.

The Bulletin 160-98 forecast of conservation savings was calculated by comparing two scenarios of 2020

crop applied water demand under differing levels of

SAE. First, crop applied water demand was computed

based on the 2020 forecast of irrigated acreage and

crop mix, but at existing (1995 base) levels of SAE for

each major crop category. Then SAE for each crop category was set to the 2020 forecast value and applied

water demand was recomputed. Applied water savings

due to conservation were taken as the difference in

applied water demand under the two scenarios.

Table 4-13 shows that agricultural water conservation would reduce applied water demands by about

800 taf annually by 2020. Such reductions of applied

water generally do not create new water supply; in most

areas of California, excess irrigation water becomes

available to other users. Even so, a reduction in ap- Table 4-13

TABLE 4-13

2020 Agricultural Water Use Reductions Due to

Conservation (taf)

Region Applied Water Depletion

North Coast 1 0

San Francisco Bay 1 0

Central Coast 82 0

South Coast 31 10

Sacramento River 203 0

San Joaquin River 148 2

Tulare Lake 45 1

North Lahontan 17 0

South Lahontan 20 10

Colorado River 249 210

Total 797 233

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The California Water Plan Update BULLETIN 160-98

plied water can serve other beneficial purposes such as

reducing leaching of plant nutrients, reducing degradation of groundwater quality, and reducing

agricultural drainage.

Only practices that lessen evaporation from water

surfaces, reduce evapotranspiration, or diminish irrecoverable losses actually reduce depletions. Efficient

water management practices have relatively little effect on evaporation and ET. It is the location of water

use, rather than the conservation measure employed,

that is key to determining whether a reduction in irrigation water application translates into a depletion

reduction. Agricultural lands adjacent to the ocean, or

where the groundwater or surface water is unacceptable for reapplication, have the greatest potential for

reducing depletions through efficient water management practices. In California, such agricultural lands

are found in the South Coast Region, the west side of

the San Joaquin Valley, and the Colorado River Region.

Other water conservation planning requirements

exist in addition to those in the agricultural MOU,

most notably those applying to water agencies contracting with USBR. (CALFED’s proposed future

water use efficiency program is discussed in Chapter6.)

The Reclamation Reform Act of 1982 directed DOI

to establish a water conservation planning program.

In 1992, CVPIA established additional water conservation requirements for federal contractors receiving

CVP supplies. USBR published criteria for CVPIA

conservation plans and is reviewing the plans which

contractors are required to submit. As of March 1998,

more than 70 federal water contractors had submitted

plans pursuant to CVPIA criteria. Discussions are underway with the agricultural council established by the

1996 MOU regarding developing a way for CVPIA

plans to be accepted as plans complying with the agricultural MOU. CVPIA further requires that new,

renewed, or amended CVP water service or repayment

contracts mandate that surface water delivery systems

have water measurement devices or comparable methods of measuring water use.

Agricultural Water Pricing. The relationship of

agricultural water pricing to water use and the role of

pricing in achieving water conservation have been subjects of discussion in recent years. For water supplied

by public agencies, the elected board members of those

agencies ultimately have the responsibility for balancing desires to achieve demand reduction through water

pricing with desires to provide affordable water rates

to growers. For self-supplied agricultural water users,

good business practices dictate maximizing water use

efficiency, in terms of crop yield per unit of water applied. Agricultural water prices in California vary

widely and are affected by factors such as geographic

location and source of water supply. Appendix 4A provides background information on agricultural water

pricing. As described in the price elasticity information in the appendix, demand for irrigation water is

generally price inelastic over the price ranges evaluated. There is no other commodity that can be

substituted for the water required to grow crops. Water costs are typically a relatively small percentage of

the total cost of producing most crops.

Crop markets, not water prices, generally dominate the economics of crop production. Bulletin

160-98 considers markets and other economic effects

in the modeling performed to forecast future irrigated

acreage, as described later in this chapter. When fully

implemented, CVPIA tiered pricing requirements may

provide new data on water price/water use relationships for CVP contractors, as described in the appendix.

Agricultural Acreage Forecasting

This section describes how 1995 base year irrigated acreage is established, and how that information

is used to forecast 2020 irrigated acreage.

Quantifying Present Irrigated Acreage. Forecasts

of future agricultural acreage start with land use data

that characterize existing crop acreage. The Department has performed land use surveys since the 1950s

to quantify acreage of irrigated land and corresponding crop types, and currently maps irrigated acreage in

six to seven counties per year. The base data for land

use surveys is obtained from aerial photography or satellite imagery, which is superimposed on a cartographic

base. Site visits are used to identify or verify crop types

growing in the fields. From this information, maps

showing locations and acreage of crop types are developed. Figure 4-6 is an example of a typical land use

survey map, showing crop types in the Ceres 7.5 minute

USGS quadrangle from the Department’s 1996

Stanislaus County survey.

The Department’s land use surveys focus on quantifying irrigated agricultural acreage. Although fields

of dry-farmed crops are mapped in the land use surveys, their acreage is not tabulated for calculating water

use. In certain areas of the State, climate and market

conditions are favorable for producing multiple crops

per year on the same field (for example, winter vegEE-RM-PET-100 C0MMENT 01A
4-23 WATER USE

The California Water Plan Update BULLETIN 160-98

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-24

The California Water Plan Update BULLETIN 160-98

etables followed by a summer cotton crop). In these

cases, annual irrigated acreage is counted as the sum

of the acreage of the individual crop types. In the years

between county land use surveys, the Department estimates crop types and acreage using data collected from

county agricultural commissioners, local water agencies, University of California Cooperative Extension

Programs, and the California Department of Food and

Agriculture.

The starting point for determining Bulletin 160-

98 1995 base acreage was normalized 1990 irrigated

acreage from Bulletin 160-93. Changes in crop acreage between 1990 and 1995 were evaluated to

determine if they were due to short-term causes (e.g.,

drought or abnormal spring rainfall), or if there was

an actual change in cropping patterns. Base year acreage was normalized to represent the acreage that would

most likely be expected in the absence of weather and

market related abnormalities. (More detail on the concept of normalizing base year data is presented in

Chapter 3.) Figure 4-7 illustrates some general trends

in California cropping patterns over time.

Crop acreage by region for the normalized 1995 base

is presented in Table 4-14. The 1995 base irrigated land

acreage is about 9.1 million acres, which, when multiple

cropped areas are tabulated, becomes a base irrigated

cropped acreage of about 9.5 million acres.

Forecasting Future Irrigated Acreage. The

California’s Nursery Industry

When people think of irrigated agriculture, crops that often

come to mind are commodities such as hay, grains, rice, row

crops, and cotton. However, nursery products (flowers, plants,

turf-grass) rank as the State’s fourth largest farm product in

gross value, behind milk/cream, grapes, and cattle, and ahead

of cotton, almonds, and hay, according to 1996 California

Department of Food and Agriculture statistics. The prominence

of the nursery industry reflects the extent of urbanization in

California, as well as favorable climatic conditions.

California nursery products had a $1.6 billion farmgate

value (wholesale value at the farm) in 1996. San Diego is the

leading California county in nursery product valuation,

followed by Santa Barbara, San Mateo, and Los Angeles

Counties. California wholesale production represents about

26 percent of national nursery product sales.

An important difference between the nursery industry and

other agricultural sectors is the extent to which the industry’s

revenues are tied to urban, as well as to agricultural, water

supplies. Bulletin 160 treats nursery water use as an

agricultural use. Many of the industry’s products, however,

are destined for urban and commercial locations where urban

water supply availability influences landscaping choices and

the market for nursery products.

About 25,000 acres are devoted to nursery products

in California. Much of the acreage is in proximity to

urbanized, coastal regions of the State near markets and major

transportation routes.

The Central Valley produces most of California’s tomato crop.

Much of the crop is used for processed tomato products, such

as canned tomatoes and tomato sauces. Acreage devoted to

truck crops like tomatoes is expected to increase in the future.

0

10

20

30

40

50

60

70

80

1970 1995 2020

C r o p A c r e a g e , P e r c e n t o f S t a t e w i d e T o t a l

Field

Crops

Trees

& Vines

Truck

Crops

General Trends in

Cropping Patterns Over Time

FIGURE 4-7

EE-RM-PET-100 C0MMENT 01A
4-25

WATER USE

TABLE 4-14

California Crop and Irrigated Acreage by Hydrologic Region, 1995 level

(thousands of acres)

Irrigated Crop NC SF CC SC SR SJ TL NL SL Grain 72 2 26 11 270 180 260 7 2 Rice 0 0 0 0 494 22 0 1 0 Cotton 0 0 0 0 9 185 1,026 0 0 

Sugar beets 6 0 3 0 54 47 30 0 0 Corn 1 1 3 4 92 212 116 0 0 Other field 3 1 16 4 155 120 97 0 1 Alfalfa 53 0 21 10 149 231 296 44 34 Pasture 122 5 18 20 352 199 49 107 18 Tomatoes 0 0 10 7 138 82 111 0 0 

Other truck 23 11 382 87 56 130 194 2 3 Almond/pistachios 0 0 0 0106 251 177 0 0 

Other deciduous 7 6 18 3 219 154 191 0 3 Subtropical 0 0 19 161 28 8 202 0 0 Grapes 36 39 56 6 17 184 378 0 0 

Total Crop Area 323 65 572 313 2,139 2,005 3,127 161 61 Multiple Crop 0 0 142 30 52 56 63 0 0 Irrigated Land Area 323 65 430 283 2,087 1,949 3,064 161 61 

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-26

The California Water Plan Update BULLETIN 160-98

Table 4-14

Department’s 2020 irrigated acreage forecast was derived from staff research, a crop market outlook study,

and results from the Central Valley Production Model.

As with any forecast of future conditions, there are

uncertainties associated with each of these approaches.

The Department’s integration of the results from three

independent approaches is intended to represent a best

estimate of future acreage, absent major changes from

present conditions. It is important to emphasize that

many factors affecting future cropped acreage are based

on national (federal Farm Bill programs) or international (world export markets) circumstances. California

agricultural products compete with products from

other regions in the global economy and are affected

by trade policies and market conditions that reach far

beyond the State’s boundaries.

The Federal Agriculture Improvement and Reform

Act of 1996, for example, affects agricultural markets

nationwide, by changing federal price supports for

specified agricultural commodities. Under the terms

of that act, federal payments to growers will be reduced

by 2002, and prior farm bill provisions that required

growers to reduce planted acreages of regulated commodities are no longer in force. (Commodities with

significant federal price support include wheat, feed

grains, rice, cotton, dairy products, sugar, and peanuts.)

The overall impact of the act to California may be less

than its impact to states whose agriculture is less diversified and who are less active in export markets. In

1994, for example, federal farm bill production payments to California growers represented about 1

percent of California’s agricultural revenue. The potential impacts of FAIRA to California’s agricultural

market are considered in Bulletin 160-98 by the crop

market outlook study.

Intrastate factors considered in making acreage

forecasts included urban encroachment onto agricultural land and land retirement due to drainage

problems (discussed in more detail in the following

section). Urbanization on lands presently used for irrigated agriculture is a significant consideration in the

South Coast Region and in the San Joaquin Valley,

based on projected patterns of population growth. (See

sidebar on water use impacts of land conversion.) DOF

2020 population forecasts, along with information

gathered from local agency land use plans, were used

Water Use Impacts from Urbanization of

Agricultural Lands—A San Joaquin Valley

Example

The Department projects a decline in California’s irrigated

acreage by 2020, due in part to urbanization of agricultural

lands. Much of this urbanization will occur in the South Coast

Region and in the San Joaquin Valley. Potential changes in

water use resulting from land use conversion are often of

concern to local agencies responsible for land use planning

or for providing water supplies. Changes in water use must

be evaluated on a site-specific basis, as the following example

for the San Joaquin Valley illustrates.

Changes in water use depend on the kinds of crops grown

and the density and type of urban development in an area. In

the case of single-family dwellings, applied water use varies

with housing density. Numerous studies have shown that

dwellings on larger lots use more water per dwelling unit due

to the larger landscaped areas. However, higher density

developments have the greater applied water use per acre of

land. A recent Department study of the Fresno area showed

that applied water use of single-family dwellings and

agricultural crops were similar at low housing densities (four

or five units per acre). However, higher density single-family

dwellings (six units or more per acre) that have become

common in today’s new home construction market tended

to have greater applied water requirements than some

crops.

Growth in the Fresno area has caused expansion of urban

development onto adjoining agricultural lands. Figure 4-8 is

a plot of Department land use data illustrating the long-term

expansion of urban development onto agricultural lands in

the area. Department data show that average urban applied

water use in the Fresno area (urban water use includes

residential, commercial, and industrial purposes) is equivalent

to about 3.2 af/acre. Typical agricultural applied water use

for crops grown in the area is shown below. Actual agricultural

applied water use for an individual crop will vary with fieldspecific conditions such as soil type and irrigation method.

Type of Use Applied Water Use

(af/acre)

Urban 3.2

Agricultural

Barley 1.3

Grapes 2.9

Cotton 3.2

Deciduous orchard 3.5

Pasture (improved) 4.5

Alfalfa 4.7

EE-RM-PET-100 C0MMENT 01A
4-27 WATER USE

The California Water Plan Update BULLETIN 160-98

S a n J o a q u i n

R i v e r

E n te r p r i se C a n a l

F r i a n t - Ke r n C an a l

F resno

Can a l

K i n g s

R i v e r

Fowle

r Switch

Canal

S a n J o a q u i n

R i v e r

E n te r p r i se C a n a l

F r i a n t - Ke r n C an a l

F resno

Can a l

K i n g s R i v e r

Fowle

r Switch

Canal

Clovis

Fresno

Raisin

City

Fowler

Sanger

180

99

41

41

41

99

180 180

168

145

Kerman

Raisin

City

Fowler

Sanger

180

99

41

41

41

99

180 180

168

145

Kerman

Fresno

Clovis

Changes in Land Use Over Time, DAU 233

FIGURE 4-8

1958

Urban

1994

Non-Urban

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-28

The California Water Plan Update BULLETIN 160-98

to identify irrigated lands most likely to be affected by

urbanization. Local water agencies and county farm

advisors were interviewed to assess their perspective

on land use changes affecting agricultural acreage. For

example, urbanization may eliminate irrigated acreage

in one area, but shift agricultural development onto

lands presently used as non-irrigated pasture. Soil types

and landforms are important constraints in agricultural land development. If urbanization occurs on

prime Central Valley farmland, some agricultural production may be able to shift to poorer quality soils on

hilly lands adjoining the valley floor. A consequent shift

in crop types and irrigation practices would likely result—for example, from furrow-irrigated row crops to

vineyards on drip irrigation.

The Department’s crop market outlook, a form

of Delphi analysis, was developed using information

and expert opinions gathered from interviews with

more than 130 University of California farm advisors,

agricultural bankers, commodity marketing specialists,

managers of cooperatives, and others. Three basic factors guided the CMO: current and future demand for

food and fiber by the world’s consumers; the share California could produce to meet this worldwide demand;

and technical factors, such as crop yields, pasture carrying capacities, and livestock feed conversion ratios

that affect demand for agricultural products. (Milk and

dairy products are California’s largest agricultural product, in terms of gross value. The demand for these

products is reflected in the markets for alfalfa, grains,

and other fodder used by dairies.) The CMO forecasts

a statewide crop mix and estimates corresponding irrigated acreage. The major findings of the CMO for

year 2020 were that grain and field crop acreage would

decrease, while acreage of truck crops and permanent

crops would increase.

The Central Valley Production Model is a

mathematical programming model that simulates

farming decisions by growers. Inputs include detailed

information about production practices and costs as

well as water availability and cost by source. The model

also uses information on the relationship between production levels of individual crops and crop market

prices. The model’s geographic coverage is limited to

the Central Valley, which represents about 80 percent

of the State’s irrigated agricultural acreage. The CVPM

results also indicated future crop shifting, from grains

and field crops to vegetables, trees, and vines. The

CVPM forecast showed a small reduction in crop acreage from 1995 to 2020.

Other Factors Affecting Forecasted Irrigated

Acreage. The process of estimating future irrigated

acreage considered statewide factors such as crop markets and urban expansion onto agricultural lands. The

Department considered an additional region-specific

factor, the long-standing agricultural drainage management issues on the west side of the San Joaquin

Valley. Drainage management issues in this area have

a dual focus—salt management to permit continued

agricultural production on lands requiring drainage

systems, and trace minerals management (principally

selenium) to limit adverse water quality and environmental impacts.

The need for drainage systems to permit farming

in some westside areas was recognized concurrently

with the development of irrigated agriculture in the

region. USBR’s San Luis Drain, for example, was originally planned to convey drainage water out of the valley

to the Delta. The drain was instead terminated at

Kesterson Reservoir, where waterfowl mortalities led

to discovery of elevated selenium levels in the early

1980s. The drain was subsequently closed. (A discussion of trial reopening of part of the drain for the

Grasslands Bypass Channel Project is provided in

Chapter 8.) Post-Kesterson studies of valley drainage

problems have sought to quantify factors such as extent of areas with shallow depths to groundwater,

tributary areas in Coast Range sediments from which

trace minerals are derived, and water quality characteristics of drain water and shallow groundwater.

The 1990 report of the interagency San Joaquin

Valley Drainage Program projected that as much as

460,000 acres of irrigated land would be taken out of

production by the year 2020 if the report’s recommendations were not implemented. The report

recommended retirement of 75,000 acres of land having the worst drainage problems by 2040. The Bulletin

160-98 year 2020 acreage forecast follows the same

procedure used in Bulletin 160-93 and assumes that

the 75,000 acres would be retired at an average rate of

1,500 acres per year. Thus, 45,000 acres of land would

be retired between 1990 and 2020. USBR’s 1997 request for proposals for the CVPIA land retirement

program (described in Chapter 6) elicited offers to sell

31,000 acres of drainage-impaired lands, suggesting

that the assumed 45,000 acres of land retirement could

occur by 2020.

Data from the Department’s monitoring program

for groundwater levels in the San Joaquin Valley are

shown in Figure 4-9. Agricultural acreage with a water

EE-RM-PET-100 C0MMENT 01A
4-29 WATER USE

The California Water Plan Update BULLETIN 160-98

Stockton

Sacramento

Bakersfield

Modesto

Santa Barbara

Fresno

FIGURE 4-9

Areas of Shallow Groundwater in the San Joaquin Valley

0 - 5 Feet

5 - 10 Feet

10 - 15 Feet

15 - 20 Feet

Depth to Free Water

(Spring 1997 Data)

CALIFORNIA

NEVADA

SAN JOAQUIN

HYDROLOGIC REGION

TULARE LAKE

HYDROLOGIC REGION

P

a

c i f i

c

O

c

e

a

n

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-30

The California Water Plan Update BULLETIN 160-98

table within 10 feet of the surface increased from

1,061,000 acres in 1991 to 1,262,000 acres in 1997.

Agricultural lands with a water table within 5 feet of

the surface increased from 311,000 acres in 1991 to

743,000 acres in 1997. Increases in the extent of shallow groundwater coincide with the end of drought

conditions and above-average rainfall. (The

Department’s monitoring program is limited to measurement of groundwater levels. There has been no

region-wide monitoring of selenium and other constituents in shallow groundwater since the 1987 work

performed for the 1990 report.)

To implement recommendations of the 1990 report, four State agencies (DWR, SWRCB, DFG, and

DFA) and four federal agencies (USBR, USFWS,

USGS, and Natural Resource Conservation Service)

signed a 1991 MOU to participate in a cooperative

interagency program. The program was to address the

management plan’s eight major recommendations:

source control, drainage reuse, evaporation ponds, land

retirement, groundwater management, limiting discharge to the San Joaquin River, and institutional

change. (The plan’s recommendations did not address

disposal of drain water outside of the Central Valley.)

Significant progress has been made on some recommendations. Some examples of drainage management

activities are described in Chapters 7-9.

In 1997, the interagency drainage program drafted

Factors that influence

the conversion of

irrigated lands to urban

use include the lands’

proximity to existing

urban areas and

transportation

corridors, and local

agency land use

planning and zoning

policies.

Agroforestry Research

Agroforestry is being tested for managing drainage impaired

lands. Agroforestry systems integrate trees and shrubs into

cropping activities to produce marketable products and/or

provide resource conservation. Agroforestry principles could

be applied to on-farm water management, where increasingly

saline water would be applied to successively more salt-tolerant

plants to reduce drainage volumes. For example, drainage

water from salt-sensitive crops could be used to irrigate a salttolerant crop like cotton. Drainage water from the cotton

would then be used to irrigate salt-tolerant trees, such as

eucalyptus. Drainage water from the trees would be reused

again to irrigate highly salt-tolerant plants such as saltgrass.

Finally, the drainage water would be discharged into a solar

evaporator. This is an experimental program. To be

commercially successful, markets would need to be found

for the eucalyptus trees and other biomass produced. In 1985

a cooperative effort among several growers and agencies began

at a 27-acre site near Mendota. A second research project of

622 acres was established at Red Rock Ranch in Fresno

County in 1993, and a third research project was started by

Tulare Lake Basin Drainage District.

EE-RM-PET-100 C0MMENT 01A
4-31 WATER USE

The California Water Plan Update BULLETIN 160-98

 Alfalfa and Market Conditions

The market for California alfalfa is closely tied to the State’s

dairy industry. California is the nation’s leading dairy state.

According to DFA’s 1996 statistics, milk/cream production

amounted to $3.7 billion, making it the State’s top-valued

agricultural commodity. California, with about 1.3 million

dairy cows and over 2,300 dairy farms, accounted for almost

17 percent of the nation’s dairy production in 1996. Leading

dairy counties are Tulare, San Bernardino, Merced, Stanislaus,

and Riverside.

 Alfalfa supports the dairy and livestock industries

(including the recreational horse industry) and also provides

about one-third of the nation’s honey production. In-state

alfalfa production does not meet all of the demand within

California. Alfalfa is trucked from the intermountain states

to Central California dairies. Although some alfalfa is exported

from California (mostly to Japan), imports into California have

exceeded exports by 1 to 8 percent over the past several years.

California milk/cream production has increased more than

50 percent in the past 12 years. About half of this increase is

due to increases in milk yield per cow and the remainder is

due to increased numbers of cows. This has created a

continuing demand for alfalfa. Most dairy rations in California

contain some component of alfalfa.

Relatively little raw milk flows into or out of the State.

California’s dairy industry is based on in-state production and

processing capacity. The demand for milk products is greatest

in the State’s major population centers — the San Francisco

Bay Area and urbanized Southern California. Dairy

production has been concentrated in the San Joaquin Valley

and in the Inland Empire region of Southern California,

within convenient distances of major markets. Increasing

urbanization of formerly agricultural lands in Southern

California is shifting more dairy production to the southern

San Joaquin Valley. To supply feed to these dairies, the San

Joaquin Valley has become the largest production area for

alfalfa in the State, producing nearly half of California’s alfalfa.

According to DFA, California’s Grade A milk production

can be broken down into the following categories:

Cheese 36%

Butter & nonfat dry milk 29%

Fluid milk products 24%

Frozen dairy products 6%

Soft products 5%

an activity plan to update the report’s recommendations with new information. The activity plan is

scheduled for completion in 1999. Source control objectives of the 1990 report have been achieved or

exceeded over large areas. In the first year of Grasslands Bypass Channel Project implementation

(described in Chapter 8), irrigation and drainage modifications by Grasslands area farmers reduced selenium

discharges to the San Joaquin River. Tiered water pricing has been implemented in the drainage problem

area of the Grasslands subarea. Three agroforestry

drainage reuse research projects have been implemented

(see sidebar).

One factor not included in Bulletin 160-98 irrigated acreage forecasts is the potential large-scale

conversion of agricultural land to wildlife habitat for

reasons other than the westside drainage problems described above. The CALFED program represents the

largest pending example of potential conversion of irrigated agricultural lands to habitat, as described in

CALFED’s March 1998 draft programmatic EIR/EIS

and supporting documents. CALFED’s potential land

conversion amounts have not been included in the Bulletin 160-98 irrigated acreage forecast because they are

preliminary at this time (a site-specific environmental

document with an implementation schedule for land

conversion has not yet been prepared), and because

CALFED’s preliminary numbers are so large relative

to the Bulletin’s market-based forecast of irrigated acreage that they would negate the results of the forecast.

Overall, CALFED program activities as presently

planned could convert up to 290,000 irrigated acres

to habitat and other uses, an amount almost as great

as the 325,000 acre reduction in irrigated acreage forecast in the Bulletin. Water use implications of

large-scale land conversions are not included in the

Bulletin 160-98 forecast. Impacts of such land conversions are expected to be addressed in the next water

plan update, when CALFED’s program may be better

defined.

The difficulty in estimating impacts from largescale land conversion programs stems from the domino

effect that changes in acreage in one location have on

acreage and crop types in other areas, and how crop

markets determine which crop shifts are feasible. For

example, CALFED’s preliminary reports suggest that

up to 190,000 irrigated acres in the Delta could be

converted to other land uses. This amount represents

about 40 percent of Delta irrigated acreage, where principal crops are corn, alfalfa, tomatoes, grain, orchard

EE-RM-PET-100 C0MMENT 01A
4-32

WATER USE

TABLE 4-15

California Crop and Irrigated Acreage by Hydrologic Region, 2020 Level

(thousands of acres)

Irrigated Crop NC SF CC SC SR SJ TL NL SL Grain 66 1 21 5 249 152 201 8 0 Rice 0 0 0 0 484 15 0 1 0 Cotton 0 0 0 0 15 171 888 0 0 

Sugar beets 6 0 2 052 18 13 0 0Corn 2 0 3 290 188 101 1 0 

Other field 3 1 14 1 154 139 110 0 0 Alfalfa 62 0 20 6 147 181 238 50 24 Pasture 123 5 16 6 316 165 26 103 18 Tomatoes 0 0 8 4141 93 130 0 0

Other truck 28 11 373 43 79 197 300 2 1 Almond/pistachios 0 0 0 0127 270 198 0 0 

Other Deciduous 7 6 20 3 234 153 199 0 2 Subtropical 0 0 18 117 33 10 215 0 0 

Grapes 38 41 75 3 29 183 366 0 0 Total Crop Area 335 65 570 190 2,150 1,935 2,985 165 45 Multiple Crop 0 0 150 10 70 80 100 0 0 

Irrigated Land Area 335 65 420 180 2,080 1,855 2,885 165 45 

EE-RM-PET-100 C0MMENT 01A
4-33 WATER USE

The California Water Plan Update BULLETIN 160-98

crops, and truck crops (e.g., asparagus). Some land

conversion in the Delta might result in production on

new agricultural lands—most likely, rolling hills on

the edge of the valley floor which are suitable for only

limited crop types (orchards and vineyards). Some of

the land conversion might result in increased demand

in other areas for the affected crops, such as increased

demand for asparagus from the Imperial and Salinas

Valleys.

Results of 2020 Acreage Forecast. Table 4-15

shows the 2020 irrigated acreage forecast. The total

irrigated crop acreage is forecasted to decline by

325,000 acres from 1995 to 2020, primarily in the

San Joaquin Valley and South Coast areas. Reductions

in crop acreage are due to urban encroachment, drainage problems in the westside San Joaquin Valley, and a

more competitive economic market for California agTABLE 4-16

Applied Agricultural Water Use by Hydrologic Region (taf)

1995 2020

Region Average Drought Average Drought

North Coast 894 973 927 1,011

San Francisco Bay 98 108 98 108

Central Coast 1,192 1,279 1,127 1,223

South Coast 784 820 462 484

Sacramento River 8,065 9,054 7,939 8,822

San Joaquin River 7,027 7,244 6,450 6,719

Tulare Lake 10,736 10,026 10,123 9,532

North Lahontan 530 584 536 594

South Lahontan 332 332 257 257

Colorado River 4,118 4,118 3,583 3,583

Total (rounded) 33,780 34,540 31,500 32,330

ricultural products. Pasture and field crops are forecasted to decline by about 631,000 acres. Truck crops

and permanent crops are forecasted to increase by about

238,000 and 68,000 acres, respectively. Acreage with

multiple cropping is forecasted to increase by 108,000

acres, reflecting the expected increased production

of truck crops. These statewide findings are used

in developing the forecasted agricultural water demands.

Summary of Agricultural Water Use

Crop water use information and irrigated acreage

data are combined to generate the 2020 agricultural

water use by hydrologic region shown in Table 4-16.

As previously noted, the 2020 forecasted values take

into account EWMP implementation, which results

in a 2020 applied water reduction of about 800 taf.

pumpkin photo

The proximity of California

agriculture to densely

populated urban markets

encourages the production

of specialty crops. Pumpkin

patches and Christmas tree

lots are examples of

specialized urban niche

markets.

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-34

The California Water Plan Update BULLETIN 160-98

Environmental Water Use

Bulletin 160-98 defines environmental water as

the sum of:

• Dedicated flows in State and federal wild and

scenic rivers

• Instream flow requirements established by water

right permits, DFG agreements, court actions, or

other administrative documents

• Bay-Delta outflows required by SWRCB

• Applied water demands of managed freshwater

wildlife areas

This definition recognizes that certain quantities

of water have been set aside or otherwise managed for

environmental purposes, and that these quantities cannot be put to use for other purposes in the locations

where the water has been reserved or otherwise managed. This definition also recognizes that these uses of

environmental water can be quantified. Unlike urban

and agricultural water use, much of this environmental water use is brought about by legislative or

regulatory processes. Certainly the environment uses

more water than is encompassed in this definition—

the rainfall that sustains the forests of the Sierra Nevada

and the North Coast, the winter runoff that supports

flora and fauna in numerous small streams, the shallow groundwater that supports riparian vegetation in

some ephemeral streams—but the Bulletin’s definition

captures uses of water that are managed (in one fashion or another) and quantifiable. As described earlier,

average annual statewide precipitation over California’s

land surface amounts to about 200 maf. About 65

percent of this precipitation is consumed through

evaporation and transpiration by the State’s forests,

grasslands, and other vegetation. The remaining 35

percent comprises the State’s average annual runoff of

about 71 maf. The environmental water demands discussed in this section are demands that would be met

through a designated portion of that average annual

runoff.

The following discussion covers factors affecting

the four categories of environmental water use. As with

urban and agricultural water use, options for meeting

future environmental water needs—such as federal

acquisition and transfer of water to meet CVPIA AFRP

goals—are covered in Chapter 6 and in the regional

water management chapters. The environmental water use categories below are discussed in order of

size—from greatest (wild and scenic rivers) to smallest

(wildlife refuges). Environmental water use is shown

on an applied water basis.

Flows in Wild and Scenic Rivers

Flows in wild and scenic rivers constitute the largest environmental water use in the State. Figure 4-10

is a map of California’s State and federal wild and scenic rivers.

The 1968 National Wild and Scenic Rivers Act,

codified to preserve the free-flowing characteristics of

rivers having outstanding natural resources values, prohibited federal agencies from constructing, authorizing,

or funding the construction of water resources projects

having a direct or adverse effect on the values for which

the river was designated. (This restriction also applies

to rivers designated for potential addition to the national wild and scenic rivers system.) There are two

methods for having a river segment added to the federal system—congressional legislation, or a state’s

petition to the Secretary of the Interior for federal designation of a river already protected under state statutes.

No new federal designations have been made since

publication of Bulletin 160-93.

A number of river systems within lands managed

by federal agencies are being studied as candidates. For

example, U.S. Forest Service draft environmental documentation in 1994 and 1996 recommended

designation of 5 streams (129 river miles) in Tahoe

National Forest and 160 river miles in Stanislaus National Forest. These waterways drain to the Central

Valley where their flows are used for other purposes,

and wild and scenic designation would not affect the

existing downstream uses.

The California Wild and Scenic Rivers Act of 1972

prohibited construction of any dam, reservoir, diversion, or other water impoundment on a designated

river. As shown on Figure 4-10, some rivers are included in both federal and State systems. No new State

designations have been made since Bulletin 160-93,

although the Mill and Deer Creeks Protection Act of

1995 (Section 5093.70 of the Public Resources Code)

gave portions of these streams special status similar to

wild and scenic designation, by restricting construction of dams, reservoirs, diversions or other water

impoundments.

Tables 4-17 and 4-18 show the wild and scenic

river flows used in Bulletin 160-98 water budgets by

waterway and by hydrologic region. The flows shown

are based on the rivers’ unimpaired flow. (The unimpaired flow in a river is the flow measured or calculated

at some specific location that would be unaffected by

stream diversions, storage, imports or exports, and return flows.) For the average year condition, the

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4-35 WATER USE

The California Water Plan Update BULLETIN 160-98

Redding Federal and State Designation

State Designation Only

Federal Designation Only

FIGURE 4-10

California Wild and Scenic Rivers

E. Fork Carson River

W. Walker River

KingsRiver

Eel

River

S. Fork

Van S. Fork

Trinity

Smith

River

Klamath

River Duzen

River

M. Fork Feather River

American River

N. Fork American

River

Tuolumne River

Merced River

S. Fork

M. Fork

S . Fork

S. Fork

River Kern Sisquoc River Sespe Creek

Big Sur River

River

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The California Water Plan Update BULLETIN 160-98

TABLE 4-18

Wild and Scenic River Flows by Hydrologic Region (taf)

1995 2020

Region Average Drought Average Drought

North Coast 17,800 7,900 17,800 7,900

San Francisco Bay 0 0 0 0

Central Coast 98 28 98 28

South Coast 69 51 69 51

Sacramento River 1,733 736 1,733 736

San Joaquin River 1,974 939 1,974 939

Tulare Lake 1,614 751 1,614 751

North Lahontan 271 154 271 154

South Lahontan 0 0 0 0

Colorado River 0 0 0 0

Total (rounded) 23,560 10,560 23,560 10,560

TABLE 4-17

Wild and Scenic River Flows by Waterway (taf)

1995 2020

Waterway Average Drought Average Drought

Klamath 9,070 3,980 9,070 3,980

Smith 2,920 1,720 2,920 1,720

Eel 5,810 2,200 5,810 2,200

Big Sur 83 22 83 22

Sisquoc 15 6 15 6

Sespe Creek 69 51 69 51

Middle Fork Feather 1,129 497 1,129 497

North Fork American 584 239 584 239

Lower American 20 0 20 0

Tuolumne 1,192 572 1,192 572

Merced 782 367 782 367

Kings 896 448 896 448

North Fork Kern 628 275 628 275

South Fork Kern 90 28 90 28

East Fork Carson 71 34 71 34

West Walker 200 120 200 120

Total (rounded) 23,560 10,560 23,560 10,560

long-term unimpaired flow from the Department’s Bulletin 1 was used. The estimated average unimpaired

flow for the 1990-91 water years was used for the

drought condition.

Instream Flows

Instream flow is the water maintained in a stream

or river for instream beneficial uses such as fisheries,

wildlife, aesthetics, recreation, and navigation. Instream

flow is a major factor influencing the productivity and

diversity of California’s rivers and streams.

Instream flows may be established in a variety of

ways—by agreements executed between DFG and a

water agency, by terms and conditions in a water right

permit from SWRCB, by terms and conditions in a

FERC hydropower license, by a court order, or by an

agreement among interested parties. Required flows

on most rivers vary by month and year type, with wet

year requirements generally being higher than dry year

requirements. Converting from net water use budgets

used in prior editions of Bulletin 160 to the applied

water budgets used in Bulletin 160-98 created a challenge in properly accounting for multiple instream

flows within a river basin. Bulletin 160-98 used a simplified approach in which only the largest downstream

flow requirement was included in the water budgets.

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The California Water Plan Update BULLETIN 160-98

This simplified approach undercounts applied instream

flow requirements on streams having multiple requirements. The Department is developing a new modeling

approach for the next water plan update that will more

accurately quantify applied instream flows.

Since the determination of 1990-level instream

flow values used as base conditions in Bulletin 160-

93, subsequent agreements or decisions have increased

or added instream flow requirements for the Trinity

River, Mokelumne River, Stanislaus River, Tuolumne

River, Owens River, Putah Creek, and Mono Lake

tributaries. In addition, ten new waterways have been

added to the Bulletin 160-98 instream flow water budgets—the Mad River, Eel River, Russian River, Truckee

River, East Walker River, Nacimiento River, San

Joaquin River (at Vernalis), Walker Creek, Lagunitas

Creek, and Piru Creek. The sidebar on American River

environmental water use illustrates how environmental water demands are treated in Bulletin 160 water

budgets.

Factors Affecting Future Instream Flows. It is

difficult to forecast future regulatory actions or agreements that could change existing instream flow

requirements. Bulletin 160-98 thus does not attempt

to quantify the outcome of future regulatory or administrative actions. Factors likely to affect future flow

requirements include listings or potential listings of

new fish species, habitat restoration programs, and programs to acquire water for environmental purposes.

Recent decisions on federal listing of coho salmon

and steelhead trout (see Chapter 2) are likely to influence water management decisions affecting these

species, but the specific actions will ultimately depend

on the outcome of consultations, biological assessments, biological opinions, and habitat conservation

plans. In 1997, the Governor’s Executive Order W159-97 created the Watershed Protection and

Restoration Council. The council oversees State watershed protection and enhancement activities,

including restoration of anadromous fish. One goal of

this effort is to provide sufficient protection to coho,

steelhead, and other anadromous salmonids to satisfy

ESA requirements. Successful implementation of this

program could lessen water supply impacts of salmonid listings.

Coho salmon are found in coastal streams and in

large river systems such as the Klamath River and its

tributaries. Some of the greatest potential for new water supply impacts could be on the Klamath River

system (including its Trinity River tributary), where

USFWS is finalizing instream flow studies for several

salmonids. Steelhead populations are distributed

Part of Sespe Creek is

included in the wild

and scenic river system.

The creek, located in

Ventura County, is

tributary to the Santa

Clara River.

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The California Water Plan Update BULLETIN 160-98

throughout coastal streams and rivers, and are also

found in the Sacramento Valley. (Wild stocks of steelhead in the Sacramento River system are mostly

confined to upper watershed tributaries such as Antelope, Deer, and Mill Creeks, and the Yuba River. The

San Joaquin River system no longer supports a significant natural steelhead population—most steelhead

found in the system are hatchery fish.) Data from the

SWP and CVP pumping plants in the southern Delta

indicate that most juvenile steelhead move through the

Delta during the winter and early spring, when BayDelta Accord restrictions are already in place. Water

supply impacts on coastal rivers and streams must be

evaluated from a basin-specific standpoint.

The spring-run chinook salmon traditionally

spawned in upper reaches of Central Valley rivers and

their tributaries. Today, Deer, Mill, and Butte Creeks

are considered crucial Sacramento River tributaries for

spring-run spawning. Sustaining populations of springrun are also found in Battle Creek, and the Feather

and Yuba Rivers, although there are questions about

the genetic integrity of these populations because of

interbreeding between fall-run and spring-run salmon.

Portions of Deer and Mill Creeks have been given special status by State legislation to help protect the fishery.

As described in Chapters 5 and 6, many habitat

restoration programs are underway and substantial

funding is available for restoration actions. Improvements such as facilitating fish passage, replenishing

spawning gravel, and restoring shaded riverine habitat

will help in efficient management of water used for

environmental purposes. Specific benefits of habitat

restoration will have to be evaluated on a watershedby-watershed basis—it is not possible to quantify

potential water supply implications of present and future habitat restoration actions at a statewide level.

Examples of programs or projects now underway are

described in later chapters.

The 1997 draft programmatic EIS for CVPIA

implementation describes federal water acquisition alternatives for the AFRP. Table 4-19 shows the amounts

proposed in alternative 4 of the draft PEIS. These flows

represent the high end of potential federal water acquisition actions. Under USBR’s assumptions for

alternative 4, the instream flows are not allowed to be

exported at the Delta. Quantification of alternative 4

flows was provided by PROSIM operations studies.

The federal agencies’ ability to acquire the water would

be subject to their finding willing sellers.

In addition to water acquisition on major rivers

Environmental Water Use—An American

River Example

As discussed in Chapter 3, the return flow from one water

use can become the supply for the next downstream use. The

applied water budgets in Bulletin 160-98 reflect the multiple

uses which supplies in a river basin may have. Reapplication

of flows in the American River for environmental purposes

provides an illustration of how the Bulletin accounts for

multiple uses in its water budgets.

The American River originates in the Sierra Nevada,

flowing generally from east to west down through the foothills

into the Sacramento Valley, ultimately reaching the

Sacramento River and the Delta. The upper watershed of the

American River consists of the north, middle and south forks.

The mainstem, or Lower American River, begins near Folsom

at the confluence of the north and south forks. Environmental

water supplies are reapplied at several locations between the

upper watershed and the Delta.

Wild and scenic environmental water demands exist on

the American River’s north fork (584 taf) and mainstem (20

taf). In Bulletin 160-98 water budgets, American River wild

and scenic flows are classified as environmental water use on

the demand side of the budget and as required environmental

instream flow on the supply side of the budget. These

environmental demands are not consumptive; hence, the

surface supplies are available for downstream use.

The American River has several instream flow requirements

on its three forks as well as on its mainstem. For example, a

54 taf (75 cfs) requirement exists below Ralston Afterbay Dam

on the middle fork and a 72 taf (100 cfs) requirement exists

below Chili Bar Dam on the south fork. The river’s largest

instream flow requirement is on the mainstem below Nimbus

Dam. This 234 taf requirement is the only American River

instream flow requirement accounted for in the water budgets.

As with wild and scenic demands, the American River

instream flow requirement is shown as environmental water

use on the demand side of the budget and as required

environmental instream flow on the supply side of the budget.

This environmental demand is not consumptive; therefore,

the surface supply is available for downstream use.

Required instream flow in the American River is reapplied

downstream to meet Delta outflow requirements. The Bulletin

160-98 water budgets classify this flow as reapplied surface

water supply. About 70 percent of the Delta’s 5.6 maf

environmental demand (4.0 maf) is satisfied through

reapplication of water released to meet environmental

instream requirements in rivers tributary to the Delta.

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The California Water Plan Update BULLETIN 160-98

TABLE 4-19

Proposed Instream Flows, CVPIA PEIS Alternative 4 (taf)

Location Region Target Average

Merced River San Joaquin River 200 194

Tuolumne River San Joaquin River 200 197

Stanislaus River San Joaquin River 200 194

Calaveras River San Joaquin River 30 27

Mokelumne River San Joaquin River 70 62

Yuba River Sacramento River 100 87

Total 800 761

for the Alternative 4 instream flows shown in the table,

the draft PEIS also proposes water acquisition on

smaller Sacramento River tributaries such as Deer, Mill,

and Battle Creeks. The draft PEIS does not quantify

target flows and acquisitions for these smaller tributaries.

 The public comment period on the draft CVPIA

PEIS closed in April 1998 and USBR and USFWS

expect to release a final PEIS in 1999, after the publication date of this Bulletin.

CVPIA authorizes DOI to acquire supplemental

water from willing sellers. At this time, no long-term

sources (e.g., long-term contracts for water transfers)

have been established—water acquired has been purchased on a year-to-year basis. It is not possible to

identify specifically how and where the supplemental

water would be obtained in the future, or what other

water demands might be reduced as a result of CVPIA

water transfers. Chapter 6 provides more detail on how

water marketing arrangements are treated in Bulletin

160 water budgets.

As discussed in Chapter 2, CVPIA also affects Trinity River instream flows, by requiring that Trinity River

flows be maintained at not less than 340 taf/yr while

USFWS conducts an instream flow study that was to

be completed by 1996. USFWS’s preliminary results

suggest that instream flows of 592 taf/yr (weighted

average of five water year types) may be proposed.

USBR, USFWS, Trinity County, and the Hoopa Valley Tribe are preparing an EIR/EIS to evaluate impacts

of the proposed flows. A draft EIR/EIS has not yet

been released. Bulletin 160-98 uses the existing

instream flow requirement of 340 taf/yr since a formal

proposal for new Trinity River instream flows has not

yet been released.

Instream Flow Summary. Tables 4-20 and 4-21

show instream flows used in Bulletin 160-98 water

budgets by waterway and by hydrologic region. The

drought year scenario shown in the tables represents

the minimum annual required flow volume. For average water years, the annual required flow volume is

computed by combining the expected number of years

in each year type (wet, above normal, normal, below

normal, and/or dry, as specified in the existing agreement or order).

In water budget computations, the Department

counts instream flows as depleted if the flows go directly to a salt sink, such as the ocean. In the Central

Valley where some instream flows may reach the ocean,

any depletions are counted toward required Delta outflow (see following section). This approach avoids

counting depletions twice—once as instream flow and

once as Delta outflow.

Bay-Delta Outflow

Environmental water use for Bay-Delta outflow is

computed by using operations studies to quantify

SWRCB Order WR 95-6 requirements. This section

briefly describes the Delta’s setting and some of its environmental resource issues. Readers interested in

detailed descriptions of Delta hydrodynamics, facilities, and environmental resources may wish to review

the extensive materials prepared by the Interagency

Ecological Program, San Francisco Estuary Program,

or CALFED program.

Setting. The Bay-Delta has two high tides and two

low tides every day. An enormous volume of water (an

average of about one-fourth of the estuary’s total volume), moves in and out of the estuary with each tidal

cycle. Tidal action and Delta outflow are two important physical processes which establish salinity gradients

and carry sediments through the system. Tidal action

and Delta outflow cause seaward-flowing fresh water

from the rivers to mix with denser landward-flowing

salt water from the ocean. The average tidal flow rate

in the Delta is about 170,000 cfs, much greater than

the average seaward flow of fresh water from rivers and

streams.

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WATER USE 4-40

The California Water Plan Update BULLETIN 160-98

Fish species covered by the CVPIA’s doubling goal are salmon, steelhead, striped bass, sturgeon, and American shad. This

sturgeon was photographed at the Steinhart Aquarium.

CVPIA Anadromous Fish Restoration Program

One provision of CVPIA directed DOI to develop (by

October 1995) and to implement a program “which makes

all reasonable efforts to ensure that, by the year 2002, natural

production of anadromous fish in Central Valley rivers and

streams will be sustainable, on a long-term basis, at levels not

less than twice the average levels attained during the period

of 1967-1991”. (The San Joaquin River between Friant Dam

and Mendota Pool is not covered by this goal.) In response to

this provision, USFWS prepared a 1995 working paper listing

many potential restoration actions (some involving instream

flows, and some not) without regard to their reasonableness.

Elements of that working paper were subsequently

incorporated into a revised draft restoration plan prepared in

May 1997. One function of the draft plan was to evaluate (at

a programmatic level) the reasonableness of implementing

potential restoration actions, given the authority and funding

provided DOI by CVPIA. (For example, a potential

restoration action that would involve modifying the diversion

works of a local water agency would only be reasonable if the

local agency wished to participate with USBR or USFWS in

the action.) The revised draft plan is scheduled to be followed

by an implementation plan that would review priority actions

to be taken in the next three to five years.

The CVPIA tools available to USFWS and USBR to carry

out the AFRP include the 800 taf of project water dedicated

for environmental purposes, the authority to acquire

supplemental water to achieve AFRP goals, and the many

physical habitat restoration measures required in the act (e.g.,

restoring spawning gravel, screening diversions, improving

fish passage at Red Bluff Diversion Dam). The CVP dedicated

water is only available to USFWS and USBR on CVPcontrolled rivers below the major project dams. For other

Central Valley waterways, the agencies are proposing to carry

out a water acquisition program to buy water to meet AFRP

needs. The quantity of water to be acquired is subject to

available federal funding and the availability of water on the

market. USBR’s 1997 draft CVPIA PEIS illustrates costs

and impacts associated with different levels of supplemental

water acquisition.

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The California Water Plan Update BULLETIN 160-98

TABLE 4-21

Instream Flow Requirements by Hydrologic Region (taf)

1995 2020

Region Average Drought Average Drought

North Coast 1,410 1,285 1,410 1,285

San Francisco Bay 17 9 17 9

Central Coast 20 9 20 9

South Coast 4 4 4 4

Sacramento River 3,397 2,784 3,397 2,784

San Joaquin River 1,169 712 1,169 712

Tulare Lake 0 0 0 0

North Lahontan 85 84 85 84

South Lahontan 107 81 107 81

Colorado River 0 0 0 0

Total (rounded) 6,210 4,970 6,210 4,970

TABLE 4-20

Instream Flow Requirements by Waterway (taf)a

1995 2020

River or Creek Average Drought Average Drought

Klamath 833 833 833 833

Trinity 341 341 341 341

Mad 46 46 46 46

Eel 49 15 49 15

Russian 142 51 142 51

Lagunitas Creek 10 9 10 9

Walker Creek 6 0 6 0

Carmel 4 2 4 2

Nacimiento 16 7 16 7

Piru Creek 4 4 4 4

Clear Creek 25 25 25 25

Cache Creek 7 7 7 7

Putah Creek 22 22 22 22

Sacramento 1,945 1,702 1,945 1,702

Feather 880 588 880 588

Yuba 274 196 274 196

Bear 10 10 10 10

American 234 234 234 234

Mokelumne 158 84 158 84

Stanislaus 187 158 187 158

Tuolumne 214 94 214 94

Merced 79 67 79 67

San Joaquin 532 309 532 309

Truckee 70 70 70 70

East Walker 15 15 15 15

Mono tributaries 82 56 82 56

Owens 25 25 25 25

Total (rounded) 6,210 4,970 6,210 4,970

a

 On streams with multiple instream requirements, only the largest downstream requirement is included in Bulletin 160-98 water budgets.

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WATER USE 4-42

The California Water Plan Update BULLETIN 160-98

Recovery Efforts for Winter-Run Chinook

Salmon

As indicated by the plot of winter-run salmon escapement,

there has been a long-term decline in the species’ population.

The ultimate goal for recovery of winter-run salmon would

be restoration of a self-sustaining, naturally spawning

population. Two efforts being conducted to help achieve this

goal are a captive broodstock program and an artificial

propagation program. The purpose of the broodstock program

is to maintain the genetic composition of the existing

population, and that of the artificial propagation program is

to stabilize and increase the naturally spawning population.

Discussions among State and federal agencies and

stakeholder groups in 1991 and 1992 led to creation of a

program to evaluate the feasibility of rearing Sacramento River

winter-run fry in captivity, so that a broodstock would be

available if wild winter-run fish were to disappear. (The

population’s small size makes it vulnerable to catastrophic loss

of a year class, such as a loss that could be caused by a chemical

spill in the vicinity of winter-run spawning areas. The captive

broodstock would provide an alternative source of genetic

material as insurance against such a loss.) Agencies

participating in funding the program include USBR, USFWS,

NOAA, the Department, and DFG. Rearing facilities were

established at the University of California’s Bodega Marine

Laboratory and the California Academy of Sciences’ Steinhart

Aquarium. Juvenile fish, beginning with the 1991 year class,

were delivered to the facilities in 1992. The parent broodstock

were wild winter-run captured in the Sacramento River.

Presently, fish from four year classes are being held at the

facilities.

The artificial propagation program entails trapping known

wild adult winter-run fish, spawning them in a controlled

environment, and rearing the offspring for release back to

the river system. As adults, the artificially propagated fish

would return to winter-run spawning areas and commingle

with wild winter-run. Artificial propagation activities were

originally begun at USFWS’s Coleman National Fish

Hatchery on Battle Creek, but fish reared at Coleman

imprinted on Battle Creek water and returned there to spawn,

rather than going to the upper Sacramento River as desired.

(There were also difficulties associated with distinguishing

between winter-run and spring-run chinook, in selecting the

fish to be propagated. Better genetic identification techniques

have been developed to address this problem.)

The most recent development in the artificial propagation

program was construction of an interim rearing facility, the

Livingston Stone National Fish Hatchery, on the mainstem

Sacramento River immediately downstream from Shasta

Dam. This facility will allow the artificially spawned winterrun salmon to imprint on mainstem Sacramento River water,

so that they will return to natural spawning grounds on the

mainstem as adults. Water supply for the hatchery is provided

via piping from the dam’s penstocks. The hatchery is

beginning operations in 1998.

Additional efforts to help recover winter-run chinook

salmon, such as screening diversions and habitat improvement

projects, are described in Chapter 8.

CVPIA directed USFWS to rehabilitate and expand

Coleman National Fish Hatchery. The hatchery was

constructed in 1942 to mitigate loss of Sacramento River

salmon spawning areas due to construction of Shasta and

Keswick Dams.

0

20

40

60

80

100

120

1970 1975 1980 1985 1990 1995

Winter-Run Salmon Escapement

E s c a p e m e n t i n T h o u s a n d s

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4-43 WATER USE

The California Water Plan Update BULLETIN 160-98

Three major components of Delta inflow include

precipitation, inflow from the Sacramento and San

Joaquin Rivers, and inflow from east side streams (including the Calaveras, Mokelumne and Cosumnes

Rivers). Figure 4-11 shows annual inflow and outflow

values for 1980-96. For this period, the average annual inflow to the Delta was 25.7 maf, more than 75

percent of which was contributed by the Sacramento

and San Joaquin Rivers.

Delta outflow is the calculated amount of water

flowing past Chipps Island at the western edge of the

Delta into Suisun Bay. The magnitude of Delta outflow controls salt water intrusion from the ocean into

the estuary. The magnitude of Delta outflow also influences the distribution of many estuarine fishes and

invertebrates. Generally, the greater the outflow, the

farther downstream estuarine fish and invertebrates

occur. The relationship between Delta outflow and

abundance of fish and invertebrates is much less clear.

Some species, such as longfin smelt and juvenile

splittail, show strong correlations between abundance

and Delta outflow. The effects of outflow on species

can vary depending on the time of year volume of

outflow.

Suisun Bay, the first bay below the Delta, receives

fresh water inflow that contributes dissolved nutrients

needed to support estuarine food chains. Adjacent to

Suisun Bay is Suisun Marsh, which includes about

58,600 acres of diked managed wetlands, tidal marsh,

and adjacent grasslands, 29,500 acres of waterways,

and a buffer zone of 27,900 acres of varying land use.

Suisun Marsh is one of the largest contiguous brackish water marshes in the United States. Nearly half of

the waterfowl and shorebirds migrating on the Pacific

flyway pass through the Bay-Delta each year, using the

Suisun marsh and other Delta wetlands as feeding and

resting stations.

Fresh water outflow from the Delta passes through

Suisun Bay and through the Carquinez Straits, entering San Pablo Bay, and eventually reaching the Golden

Gate. By comparison, there is limited fresh water outflow and tidal circulation at the southern end of San

Francisco Bay. Fresh water outflow to the South Bay

comes from local tributaries such as Coyote Creek and

the Guadalupe River. San Pablo Bay and the South

Bay both offer shallow water habitat. National wildlife refuges—the San Pablo Bay NWR and the San

Francisco Bay NWR—occupy parts of the shoreline

in these areas. See Figure 4-12 for a location map of

the Bay-Delta.

0

10

20

30

40

50

60

70

80

1980 1985 1990 1995

Annual Delta Inflow and Outflow 1980-96

FIGURE 4-11

F l o w i n m a f

Inflow Outflow

a

a 1983 was the wettest year in Northern California in this century.

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WATER USE 4-44

The California Water Plan Update BULLETIN 160-98

North Bay Aqueduct

River

Sacramento

San

Aqueduct

Joaquin

River

Delta-Mendota

Canal

Lodi

River

Sacramento

San Francisco

San Pablo 

Bay

el

Clifton Court

Forebay

mne

Aqueduct

California

Aqueduct

South

TracyPumping

Plant

P a ci f ic O ce a n

Banks Pumping

Plant

San Francisco Bay

Hetch Hetchy

Aqueduct

uct

Rio Vista

Fairfield

Vallejo

Vacaville

Costa Canal

Bay

Mok umne

San Jose

Barker Slough

Pumping Plant

Suisun

Bay Honker

Bay

Contra

Grizzly

Bay

elumne

Mok

FIGURE 4-12

Bay-Delta Estuary

Coyote

Creek

Guadalupe

Calaveras River

Stockton

River

Mokelu

Pilarcitos

Lake

San Andreas

Lake

Crystal

Springs

Reservoir

Aqued

mnes Cosu

River

Twitchell

Island

Sherman

Island

Chipps

Island

Suisun

Marsh

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The California Water Plan Update BULLETIN 160-98

Delta Fish Species of Special Concern. About

two-thirds of California’s salmon migrate through the

Delta, including species having commercial importance

(fall-run chinook salmon), as well as listed or candidate species (winter-run chinook, spring-run chinook,

and steelhead trout). Resident fish species of special

concern include Delta smelt (listed as threatened under both the State and federal ESAs) and splittail

(proposed for federal ESA listing). Habitat needs of

anadromous and resident Delta species of special concern were reflected in actions taken in the Bay-Delta

Accord and in SWRCB’s Order WR 95-6. The accord’s

provisions for coordination of CVP and SWP operations in the Delta with the presence of fish species of

concern have been reflected in actions by the CALFED Operations Group to reduce Delta exports at

times when monitoring indicated that significant numbers of certain fish species were present in the southern

Delta. Day-to-day management of CVP and SWP

Delta operations under near real-time conditions requires extensive data collection and monitoring

support. The Interagency Ecological Program, a cooperative effort of nine State and federal agencies

(DWR, DFG, SWRCB, USBR, USFWS, EPA,

NMFS, USACE, and USGS), acquires and disseminates near real-time fish distribution and abundance

The Delta is characterized

by miles of meandering

waterways and leveed

islands used mainly for

agricultural purposes.

Delta smelt, native to

the Bay-Delta, have a

one year life span and

relatively low

reproductive rate,

making their population

abundance sensitive to

short-term habitat

changes.

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-46

The California Water Plan Update BULLETIN 160-98

data used by the CALFED Operations Group.

Populations of native species of special concern

are affected by a variety of factors, many of which are

not related to Delta outflow. One nonflow factor now

receiving more attention is competition from introduced aquatic species (see Chapter 2 for a description

of the National Invasive Species Act of 1996). Introduction of non-native species into an ecosystem can

alter the pre-existing balance achieved among the native species. Native species’ populations can be reduced,

for example, when introduced species out-compete the

native species for food or otherwise alter the food chain,

or when introduced species prey upon native species.

In the Bay-Delta, new introductions are occurring in a system that already has numerous introduced

species. Researchers estimate that the Bay-Delta is now

home to at least 150 introduced plant and animal species, some of which were introduced deliberately

(planting of game fish species such as striped bass) and

others whose arrival was accidental (discharge of invertebrates in ship ballast water). The Asian clam, for

example, was first detected in the Bay in 1986 and has

now become the most abundant mollusk in the northern part of the Bay. This clam is a voracious feeder on

the phytoplankton which supports other aquatic species. The zebra mussel—which has caused millions of

dollars of damage in the Great Lakes states—has not

yet been detected in the Delta, but experts believe that

it may be only a matter of time before the mussel arrives. Invasive plant species in the Delta include Egeria

densa and Arundo Donax (giant reed). Hydrilla, another well-known invasive aquatic plant, is now found

in Clear Lake in Northern California, and control

measures are being taken to eradicate it there, to prevent its spread to Delta waterways.

Quantifying Delta Outflow Requirements.

SWRCB Order WR 95-6 established numerical objectives for salinity, river flows, export limits, and Delta

outflow. DWRSIM operations studies were used to

translate these numerical objectives into Delta outflow

requirements for average and drought year scenarios.

The studies computed outflow requirements of approximately 5.6 maf in average years and 4.0 maf in

drought years.

Wetlands

The wetlands component of environmental water

use is based on water use at freshwater managed wetlands, such as federal national wildlife refuges and State

wildlife management areas. The following text reviews

the status of wetland acreage in California and wetland management programs, then discusses

quantification of water demands and supplies for wetlands.

In general, wetlands can be divided into saltwater

and brackish water marshes (usually located in coastal

areas) and freshwater wetlands (generally located in

inland areas). Five areas of California contain the largest remaining wetlands acreage in the State—the

Central Valley, Humboldt Bay, San Francisco Bay,

Suisun Marsh, and Klamath Basin. The majority of

the State’s wetland protection and restoration efforts

are occurring in these areas. Nontidal wetlands usually depend on a supplemental water supply, and

protecting or restoring them may create demands for

freshwater supplies.

Wetlands Policies and Programs. Many programs

and policies have been adopted by federal, State and

regional agencies and private entities to protect and

restore wetlands in California. Several of the more reThe Asian clam was first detected in the San Francisco Bay in

1986. By the early 1990s, it was the most abundant mollusk

in the northern part of the Bay.

Much of the land in the Suisun Marsh is owned and managed

by private gun clubs for duck hunting. DFG manages a

wildlife area on Grizzly Island.

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4-47 WATER USE

The California Water Plan Update BULLETIN 160-98

California is a wintertime destination for migratory waterfowl on the Pacific flyway. Managed wetlands provide feeding,

resting, and overwintering sites for the waterfowl.

cent wetland programs and policies are discussed below.

Ecosystem restoration is a large part of the CALFED program. CALFED’s draft ERP plan proposes

habitat restoration goals that include creating 64,000

acres of seasonal and perennial wetlands and 2,000 acres

of riparian habitat, returning 37,000 to 57,000 acres

to tidal action and enhancing 8,000 acres of existing

seasonal wetlands. About 1,700 acres of wetland restoration projects were funded under the accord’s

Category III program in 1995 and 1996.

CVPIA required DOI to provide water supplies

to the wetlands areas shown in Table 4-22. The

Sacramento Valley refuges were to be provided with

water supplies specified in a 1989 refuge water supply

investigation prepared by USBR, and the San Joaquin

Valley wetlands areas with supplies specified in USBR’s

San Joaquin Basin Action Plan/Kesterson Mitigation

Action Plan. This water supply was to be provided in

two increments—the first corresponding to the existCalifornia Wetlands Conservation Policy

In 1993, a California wetlands conservation policy was

established. The goals of the policy were to establish a

framework and a strategy that would:

• Ensure no overall net loss and achieve a long-term net gain

in the quantity, quality, and permanence of wetlands acreage

and values in California in a manner that fosters creativity,

stewardship, and respect for private property.

• Reduce procedural complexity in the administration of

State and federal wetlands conservation programs.

• Encourage partnerships to make landowner incentive

programs and cooperative planning efforts the primary

focus of wetlands conservation and restoration.

The policy recommended completion of a statewide

inventory of wetlands which would lead to the establishment

of a formal wetland acreage goal. This inventory is in progress.

The Resources Agency expects these policies to result in

improved status for 30 to 50 percent of the State’s wetlands

by the year 2010. Based on an estimate of 450,000 acres of

existing wetlands in the State, as much as 225,000 acres of

wetland could be improved, restored or protected.

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-48

The California Water Plan Update BULLETIN 160-98

ing average annual deliveries that the wetlands had been

receiving from drain water and other sources, and the

second corresponding to the ultimate or optimum

management levels of the wetlands. The first increment of water supply (Level 2) was to be provided by

reallocation of CVP supplies. The second increment

(Level 4) was to be acquired through purchases from

willing sellers. DOI was to acquire all of the second

increment of supply by 2002. USBR has operated the

CVP to provide the Level 2 supplies, and has been

making year-to-year short-term water purchases for the

increments of Level 4 supply. USBR and USFWS have

been studying conveyance alternatives (and groundwater extraction, in addition to surface water supply

alternatives) associated with making these increased

supplies available to the refuges.

CVPIA also required DOI to prepare a report by

September 1997 to investigate methods of improving

water supplies in the Central Valley for existing private wetlands and for 120,000 acres of new wetlands.

The 120,000 acres came from wetland restoration objectives of a Central Valley Habitat Joint Venture report. USFWS’s report is currently in preparation.

Additionally, the act required that financial

incentives be made available to farmers within the CVP

service area for flooding agricultural lands to provide

waterfowl habitat. The incentives include cost-sharing

for water purchases, pumping costs, facility construction (e.g., water control structures), and upgrades or

maintenance to existing facilities. CVPIA caps the

funding for this program at $2 million per year and

the program terminates in 2002.

In 1986, the North American Waterfowl Management Plan was signed by the United States and Canada.

The plan was updated in 1996 and Mexico became a

signatory. NAWMP provides a framework for waterfowl management in North America through 2010; it

includes numerical goals for waterfowl populations and

for habitat protection, restoration, and enhancement.

Implementing NAWMP is the responsibility of joint

ventures in which governmental agencies and private

organizations pool resources to address habitat needs.

TABLE 4-22

CVPIA Refuge Water Suppliesa (taf)

Refuge Level 2 Supply at Level 4 Supply at

Refuge Boundary Refuge Boundary

Sacramento Valley Refuges

Sacramento National Wildlife Refuge 46.4 50.0

Delevan National Wildlife Refuge 20.9 30.0

Colusa National Wildlife Refuge 25.0 25.0

Sutter National Wildlife Refuge 23.5 30.0

Gray Lodge Wildlife Management Area 35.4 44.0

Total for Sacramento Valley Refuges 151.2 179.0

San Joaquin Valley Refuges

San Luis National Wildlife Refuge 19.0 19.0

Kesterson National Wildlife Refugeb 10.0 10.0

Volta Wildlife Management Area 13.0 16.0

Los Banos Wildlife Management Area 16.6 25.5

San Joaquin Basin Action Lands

Freitas 5.3 5.3

West Gallo 10.8 10.8

Salt Slough 6.7 10.0

China Island 7.0 10.5

Grasslands Resource Conservation District 125.0 180.0

Mendota Wildlife Management Area 27.6 29.7

Merced National Wildlife Refuge 15.0 16.0

East Gallo 8.9 13.3

Kern National Wildlife Refuge 9.9 25.0

Pixley National Wildlife Refuge 1.3 6.0

Total for San Joaquin Valley Refuges 276.1 377.1

Total for all Refuges 427.3 556.1

a

 Table is excerpted from 1997 draft CVPIA PEIS.

b Kesterson NWR was merged with San Luis NWR subsequent to CVPIA enactment.

EE-RM-PET-100 C0MMENT 01A
4-49 WATER USE

The California Water Plan Update BULLETIN 160-98

There are four NAWMP joint ventures covering parts

of California. A fifth joint venture is being considered

in Southern California. The four existing joint ventures are described below.

The Central Valley Habitat Joint Venture, established in 1988, was the first California joint venture.

CVHJV adopted six goals for the Central Valley:

• Protect 80,000 acres of wetlands through fee

acquisition or conservation easement.

• Restore (and protect) 120,000 acres of former

wetlands.

• Enhance 291,555 acres of existing wetlands.

• Enhance water-based habitat on 443,000 acres

of private agricultural land.

• Secure 402,450 af of water for 15 refuges in the

Central Valley.

• Secure CVP preference power for public and private

lands dedicated to wetland management (i.e., provide

access to low-cost power generated at CVP facilities).

In 1990, the Legislature authorized the Inland

Wetlands Conservation Program administered by the

Wildlife Conservation Board. This program carries out

some CVHJV objectives by administering a $2 million per year program to acquire wetland habitat.

The Pacific Coast Joint Venture encompasses

coastal wetlands, major rivers, and adjacent uplands

from northern British Columbia to the northern edge

of San Francisco Bay. In California, there are two focus areas with strategic plans outlining specific target

areas and acreage objectives. Almost all the wetlands

are coastal projects with little or no freshwater requirements. Objectives for the northern focus area (Del

Norte and Humboldt counties) are:

• Maintain 22,000 acres of seasonal wet pasture in agricultural usage compatible with water-associated

wildlife.

• Permanently protect an additional 10,500 acres of

key wetlands through easements or fee acquisitions.

• Protect, restore, and enhance 10,100 acres of wetlands

on existing public lands.

• Assist landowners to protect, enhance, and restore

5,000 acres through cooperative projects.

Objectives of the southern focus area (Mendocino,

Sonoma, and Marin Counties excepting watersheds

draining to San Francisco Bay) are:

• Permanently secure through fee acquisition or easements an additional 20,000 acres of coastal and interior wetlands, riparian habitats, and associated uplands.

• Restore 3,500 acres of reclaimed coastal and interior

wetlands on private and public lands.

• Enhance 5,500 acres of coastal and interior wetlands

and riparian habitats on public and private lands.

Approximately half of the acreage in the southern

focus area is inland (nontidal) habitat requiring fresh

water.

The Intermountain West Joint Venture encompasses parts of Canada and Mexico and all or part of

eleven western states, including eastern California. The

California action group has completed a working agreement and drafted plans for six focus areas. Acreage goals

for acquisition, restoration, and enhancement have not

been established.

The San Francisco Bay Joint Venture was established in 1995. Its management board is drafting an

implementation strategy. Formal acreage goals and

timelines for acquisition and restoration projects will

be established. It is expected that many of the areas

protected or restored by the SFBJV will be tidal areas

with little or no fresh water requirement.

Refuge Water Supply Conservation Programs.

In the spring of 1997, a refuge water supply interagency

coordinated program task force was formed as an outgrowth of discussions in CALFED and CVPIA

programs regarding the need to have best management

practices for water conservation on wildlife refuges.

The goal of the task force is to develop a common

methodology for water management planning, including water conservation actions, for the federal, State,

and private refuges covered in CVPIA’s refuge water

supply provisions. A draft document containing BMPs

or efficient water use guidelines for the refuges is scheduled to be released for public review in 1998.

Wetlands Water Use. Bulletin 160-98 quantifies

applied water needs only for managed wetlands, because other wetlands types such as vernal pools or

coastal wetlands use naturally-occurring water supply

(precipitation or tidal action). Managed wetlands are

defined for the Bulletin as impounded freshwater and

nontidal brackish water wetlands. Managed wetlands

may be State and federal wildlife areas or refuges, private wetland preserves owned by nonprofit

organizations, private duck clubs, or privately owned

agricultural lands flooded for cultural practices such

as rice straw decomposition. Figure 4-13 shows

California’s publicly owned wetlands. Some of the largest concentrations of privately owned wetlands are the

duck clubs in the Suisun Marsh and the flooded rice

fields in the Sacramento Valley. (Acreage of rice fields

flooded to enhance decomposition of stubble remaining after harvest and to provide habitat for

EE-RM-PET-100 C0MMENT 01A
WATER USE 4-50

The California Water Plan Update BULLETIN 160-98

N.W.R. = National Wildlife Refuge

W.A. = Wildlife Area

Publicly-Owned Fresh Water Wetlands

FIGURE 4-13

Shasta Valley W.A.

Butte Valley W.A.

Lower Klamath N.W.R.

Tule Lake N.W.R.

Clear Lake N.W.R.

Modoc N.W.R.

Ash Creek W.A.

Willow Creek W.A.

Honey Lake W.A.

Upper Butte Basin W.A.

Sacramento River N.W.R.

Sacramento N.W.R.

Delevan N.W.R.

Gray Lodge W.A.

Butte Sink N.W.R.

Colusa N.W.R. 

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

Sutter N.W.R.

Yolo Bypass W.A.

Stone Lakes N.W.R.

Grizzly Island W.A.

North Grasslands W.A.

San Luis N.W.R.

Merced N.W.R.

Volta W.A.

Los Banos W.A.

Mendota W.A.

Pixley N.W.R.

Kern N.W.R.

San Jacinto W.A.

Imperial W.A.

Salton Sea N.W.R.

10

11

13

12

15

16

17

18

19

20

21 22

23 24 25

26

27

28

29

30

31

14

1

2 3 4 5

6

7

8

9

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4-51 WATER USE

The California Water Plan Update BULLETIN 160-98

overwintering waterfowl was identified by Department

land use surveys.)

State and federal wetlands in the Central Valley

are normally managed to support several types of wildlife use areas—permanent marsh, seasonal marsh,

irrigated waterfowl food crops (such as millet, rice, or

smartweed), and non-irrigated uplands. Each has different applied water requirements, as indicated in

Table 4-23, which shows typical ranges for Central

Valley wetlands. Table 4-24 shows wetlands water demands by region.

TABLE 4-23

Ranges of Applied Water on Central Valley

Managed Wetlands (af/acre/year)

Type of Use Applied Water

Permanent marsh 5-10

Seasonal marsh 2-10

Irrigated waterfowl food crops 1-4

Summary of Environmental Water Use

Table 4-25 shows base 1995 and forecasted 2020

environmental water use by hydrologic region. The

large values in the North Coast Region illustrate the

magnitude of demands for wild and scenic rivers in

comparison to other environmental water demands.

Water Use Summary by Hydrologic

Region

Tables 4-26 and 4-27 summarize California applied water use by hydrologic region. The tables

combine the urban, agricultural, and environmental

water use described in this chapter. These demands,

together with the water supply information presented

in Chapter 3, are used to prepare the statewide water

balance shown at the beginning of Chapter 6 and the

regional water balances shown in Chapters 7-9.

TABLE 4-25

Applied Environmental Water Use by Hydrologic Region (taf)

1995 2020

Region Average Drought Average Drought

North Coast 19,544 9,518 19,545 9,518

San Francisco Bay 5,762 4,294 5,762 4,294

Central Coast 118 37 118 37

South Coast 100 82 104 86

Sacramento River 5,833 4,223 5,839 4,225

San Joaquin River 3,396 1,904 3,411 1,919

Tulare Lake 1,672 809 1,676 813

North Lahontan 374 256 374 256

South Lahontan 107 81 107 81

Colorado River 39 38 44 43

Total (rounded) 36,940 21,240 36,980 21,270

TABLE 4-24

Wetlands Water Use by Hydrologic Region (taf)

1995 2020

Region Average Drought Average Drought

North Coast 325 325 325 325

San Francisco Bay 160 160 160 160

Central Coast 0 0 0 0

South Coast 27 27 31 31

Sacramento River 632 632 632 632

San Joaquin River 230 230 240 240

Tulare Lake 50 50 53 53

North Lahontan 18 18 18 18

South Lahontan 0 0 0 0

Colorado River 39 38 44 43

Total (rounded) 1,480 1,480 1,500 1,500

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4-52

WATER USE

TABLE 4-27

California Drought Year Water Use by Hydrologic Region (taf)

1995 2020

Region Urban Agricultural Environmental Total Urban Agricultural Environ

(rounded) 

North Coast 177 973 9,518 10,670 212 1,011 9,5

San Francisco Bay 1,358 108 4,294 5,760 1,428 108 4,2Central Coast 294 1,279 37 1,610 391 1,223 South Coast 4,382 820 82 5,280 5,612 484 Sacramento River 830 9,054 4,223 14,110 1,236 8,822 4,2

San Joaquin River 583 7,244 1,904 9,730 970 6,719 1,9Tulare Lake 690 10,026 809 11,530 1,099 9,532 8

North Lahontan 40 584 256 880 51 594 2

South Lahontan 238 332 81 650 619 257 

Colorado River 418 4,118 38 4,570 740 3,583 Total (rounded) 9,010 34,540 21,240 64,790 12,360 32,330 21,2

TABLE 4-26

California Average Year Water Use by Hydrologic Region (taf)

1995 2020

Region Urban Agricultural Environmental Total Urban Agricultural Environ

(rounded) 

North Coast 169 894 19,544 20,610 201 927 19,5

San Francisco Bay 1,255 98 5,762 7,110 1,317 98 5,7Central Coast 286 1,192 118 1,600 379 1,127 1

South Coast 4,340 784 100 5,220 5,519 462 1Sacramento River 766 8,065 5,833 14,660 1,139 7,939 5,8

San Joaquin River 574 7,027 3,396 11,000 954 6,450 3,4

Tulare Lake 690 10,736 1,672 13,100 1,099 10,123 1,6

North Lahontan 39 530 374 940 50 536 3

South Lahontan 238 332 107 680 619 257 1

Colorado River 418 4,118 39 4,570 740 3,583 Total (rounded) 8,770 33,780 36,940 79,490 12,020 31,500 36,9

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The California Water Plan Update BULLETIN 160-98

EE-RM-PET-100 C0MMENT 01A
4A-1 APPENDIX 4A

The California Water Plan Update BULLETIN 160-98 Appendix 4A

This appendix is provided as background to respond to interest expressed by Bulletin 160-98

reviewers in water pricing information. Water prices

in California vary widely, as discussed below. The more

than 2,800 local agencies in California that provide

water service establish their prices based on factors specific to their individual service areas, and those prices

are generally reviewed by agencies’ elected or appointed

boards of directors, or by the California Public Utility

Commission. Public agencies are not permitted to

make a profit from their water sales, and the profits

that privately owned water purveyors are allowed to

make are established by the PUC.

Water Retail Pricing

Many factors influence the prices charged by water agencies. For public water agencies, the types of

charges they may levy depend upon the legislation

under which they were created. Table 4A-1 shows types

of California water supply agencies. Descriptions of

the general powers of the public agencies shown in the

table can be found in DWR’s Bulletin 155-94, General Comparison of Water District Acts.

Investor-owned utilities’ water rates are set by the California Public Utilities Commission. Privately owned

mutual water companies set rates for their members.

TABLE 4A-1

Types of Local Supply Water Agencies in Californiaa

Type Ownership Number

County Service Area Public 880

Mutual Water Company Private 801

Community Services District Public 309

Investor-Owned Water Utility Private 195

County Water District Public 178

Water District Public 157

Irrigation District Public 97

Public Utility District Public 52

Flood Control and Water Conservation District Public 41

County Water Works District Public 40

Municipal Water District Public 40

Water Agency or Water Authority Public 31

Water Conservation District Public 13

Water Storage District Public 8

Municipal Utility District Public 5

Water Replenishment District Public 2

Metropolitan Water District Public 1

Total 2,850

a

 Water supply may also be provided by local agencies having other purposes (e.g., reclamation districts).

Source: Department of Health Services and State Controller’s Office data, 1994-96.

Urban and Agricultural Water Pricing

4A

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4A 4A-2

Appendix 4A The California Water Plan Update BULLETIN 160-98

Acquisition and Delivery Costs

 Acquisition costs are costs associated with obtaining water from a source. These costs may vary greatly

from one source to another. Some water agencies have

developed their own supply sources, some purchase

water wholesale from larger agencies, and some have a

mix of their own supplies plus wholesale purchases.

Other costs include transportation and local delivery

charges and water treatment costs. Supplies delivered

for urban use require treatment, which is becoming

an increasingly greater component of total cost as more

stringent drinking water quality regulations are put into

place. Compliance with surface water filtration and

information collection requirements of the Safe Drinking Water Act, for example, is a substantial cost item

for many water agencies.

Some water agencies use water rates to fully recover the costs of acquiring, treating, and delivering

supplies, others use a combination of water rates and

local property taxes. Another important consideration

is whether a water agency sets its rates to reflect shortterm or long-term costs. This is significant if a water

agency’s system is currently operating at capacity and

major system improvements are needed. In this case,

the water agency may have to increase rates to reflect

the higher marginal costs of future system expansion.

 During droughts, the rates water agencies charge

may vary depending on supply availability. Agencies

may have to acquire water from outside sources to meet

service area needs or may have to construct interties or

other conveyance system improvements to bring purchased supplies to their system. Many water agencies

adopted higher rates to fund programs to encourage

water conservation during the 1987-92 drought, and

several implemented drought penalty rates intended

to reduce water use drastically.

Characteristics of Service Area

A water agency’s costs will be affected by the mix of

residential, commercial, industrial, governmental, and

agricultural users within the service area because the cost

of service to different classes of users is likely to be different. If a water agency serves a heavily populated area with

many connections per square mile, the average fixed costs

per customer will tend to be less. Conversely, if the purveyor serves a sparsely populated area, average fixed costs

of serving each customer will normally be high. Because

of pumping costs, changes in elevation within a service

area can also affect delivery costs.

Rate Structure

Water rates are the primary source of income for

most water agencies. Although rates can be structured

many ways, they typically include fixed charges,

consumption-based charges, or both.

Fixed charges recover some or all of costs incurred

regardless of the amount of water used, such as debt

service incurred from project construction. Fixed

charges are typically used by water agencies that do

not meter consumption. Examples of fixed charges for

metered urban water agencies include billing and administrative charges (service charges), lifeline charges

for a minimum level of service, readiness to serve

charges, and fire protection charges. Agricultural fixed

charges (often called water availability or standby

charges) can be levied on a per acre or connection basis. Fixed charges which are levied on a per acre or

parcel basis will likely be affected by Proposition 218,

discussed in more detail in Chapters 2 and 6.

Consumption-based charges are set on a per unit

volume basis so the total charge varies with the user’s

consumption. These charges typically recover variable

costs of water deliveries (water purchases, treatment,

and pumping). As with fixed rates, there are several

forms of consumption-based rates. One form is the

constant charge, which is the same unit price for all

units of water consumed. Another is block rates, which

decrease (declining block) or increase (increasing block)

with water consumption. A declining block rate sets a

reduced price per unit for increased usage. Increasing

block rates set increasing prices per unit for increased

usage. Constant and increasing block rates are the predominant urban rate structures currently used in

California. Some forms of declining rates are still used

in urban areas, especially in communities using lower

water rates as an incentive for industry to locate in

their area. Some agencies use declining block rates and

other incentives to encourage use of recycled water in

lieu of potable supplies. Agricultural water agencies

levy consumption-based charges based upon either the

actual amount of water delivered or on the number of

irrigated acres (charges may vary depending upon the

crop type).

Fixed charges and consumption-based charges

typically account for most of a water agency’s total revenues. Revenues can also be obtained from assessments,

or taxes, levied upon lands in accord with benefits received from an agency’s actions. Assessments recover a

portion of an agency’s fixed costs, and can be levied

EE-RM-PET-100 C0MMENT 01A
4A-3 APPENDIX 4A

The California Water Plan Update BULLETIN 160-98 Appendix 4A

either on lands which directly benefit from water deliveries (for example, land receiving irrigation water)

or on lands which indirectly benefit from water deliveries (adjoining lands which may benefit from

groundwater recharge resulting from the deliveries).

Cities may charge for sewers and sewage treatment

based on water use. In some cities, the sewer charges

are included in monthly service charges and commodity rates paid by the water users. Other cities charge

for sewers based on water use, but keep the sewer

charges separate from the water charges.

Urban Retail Water Costs

Since 1990 there have been a few statewide surveys of urban retail water costs in California. One,

conducted by the Department in 1991, included about

70 communities. The results of this survey are described

in the Department’s Bulletin 166-4, Urban Water Use

in California. DHS conducted another survey in 1990,

and three others were conducted by a private consulting firm in 1993, 1995, and 1997. (The 1993-1997

surveys were based on an assumed monthly consumption of 1,500 cubic feet of water per connection, an

amount much lower than that used by many households. This assumption limits the usefulness of the

survey data.) At a statewide level of coverage, there are

no recent retail pricing data based on actual water use

amounts.

In 1994, the accounting firm of Ernst & Young

conducted a national water rates survey which

MWDSC summarized in its 1995 Integrated Resources

Plan. That survey showed that the national average for

retail urban water supply was almost $600/af.

MWDSC’s average was about $625/af; San Francisco’s

was about $560/af; and Oakland’s was almost $700/

af. (Other urban areas had higher costs. Indianapolis

was about $725/af; Houston was almost $900/af, and

Nashville was more than $1,100/af.)

Impacts of Retail Prices on Water Use

Price elasticity studies are used to characterize price

responsiveness—the degree that water users increase

or decrease use in response to a change in water price.

Economists define price elasticity of demand as the

ratio of the percentage change in quantity of water

used to the percentage change in the price of water.

When faced with a significant water price increase,

urban water users may react in one of three ways:

• They may use substantially less water. In this case,

water users are sensitive to price changes, and demand is defined to be elastic (its absolute elasticity

value is equal to or greater than one). For example,

if a 10 percent increase in price caused a 10 percent reduction in demand, economists would

define demand as elastic.

• They may use a little less water. In this case, water

users are not very sensitive to price changes, and demand is said to be inelastic (absolute elasticity value

is less than one). For example, if a 10 percent price

increase caused a 5 percent reduction in demand,

demand would be defined as inelastic.

• They may continue to use the same amount as

before. In this case, the water users are completely

insensitive to price changes, and demand is said

to be perfectly inelastic (elasticity value is equal to

zero).

A 1989 EBMUD study, for example, estimated

price elasticity of demand for its residential water supply to be -0.202 from 1981 through 1987. This means

that a water price increase of 10 percent could be expected to lower the amount of water use by about 2

percent. The demand for water in this case was inelastic—residential water users were found to be relatively

insensitive to price changes. This has been the case for

most studies of residential water demand.

Factors that can affect elasticity include climate,

housing type, water users’ income, percentage share of

water bills in users’ budgets, water rate structure, water conservation measures and education, and users’

preferences regarding water use (some users may prefer to irrigate large turf areas regardless of cost). Table

4A-2 provides a survey of recent literature on urban

water price elasticities of demand. These studies were

performed with statistical modeling which employed

historical water use, water price, and demographic and

climatic data.

Elasticity estimates derived for one geographic area

are not necessarily representative of another area because of these many potential variables. It is generally

not correct to take a value of residential price elasticity

estimated for one community during one period of

time and to assume that it is applicable to another community, or for another period of time. Only by carefully

examining the factors described above can elasticities

developed under one set of circumstances be reasonably used for estimating elasticities under other

circumstances.

For Bulletin 160-98, the Department contracted

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APPENDIX 4A 4A-4

Appendix 4A The California Water Plan Update BULLETIN 160-98

TABLE 4A-2

Urban Water Demand Price Elasticity Studies

Author(s) Study Study Type of Estimated Range of Equivalent Prices

Date Area Demand Elasticity Study Water ($/af)a

Prices

Moncur 1987 Honolulu, Hawaii Short-term -0.265 $0.22 - $0.36 $72 - $117

residential /1,000 gal

Long-term -0.345 (1983 dollars)

residential

Metzner a 1989 San Francisco Long-term -0.25 $0.73 - $0.78 $318 - $340

residential /100 cu ft

(1995 dollars)

Weber 1989 EBMUD Long-term -0.01 to -0.25 $0.24 - $0.94 $105 - $409

residential /100 cu ft

(1989 dollars)

Nieswiadomyb 1989 Denton, Texas Long-term -0.55 to -0.86 $0.27 - $0.56 $88 - $183

& Molina residential /1,000 gal

(1967 dollars)

Billings & Day 1989 Tucson, Arizona Long-term -0.72 $6.60 - $11.20 $7 - $11

residential monthly bills monthly bills

1974 -1980

(1974 dollars)

MWDSC 1990 South Coast Long-term Not Available Not Available

Region single-family

residential

Summer -0.29 to -0.36

Winter -0.03 to -0.16

Schneider & 1991 Columbus, Ohio Short-term -0.262 Not Available Not Available

Whitlach residential

Long-term -0.110

residential

Short-term -0.504

total urban

Long-term -0.123

total urban

Renwick et al. 1996 8 California cities Long-term -0.16 $0.47-$4.25 $205-$1,851

single-family /100 cu ft

residential

a

 Water rate data was unavailable from the study author. The Department retrieved the historical data and inflated the prices to 1995 levels for display

purposes only.

b Study was for summer months only and was a five-year period of recently adopted increasing block rates. Adjusted R2

 for models which produced -0.86 and

-0.55 elasticities was only 0.26 and 0.11, respectively.

with University of California researchers for an evaluation of the effects of water pricing and non-pricing

demand reduction actions (e.g., public education, rationing, subsidies for adoption of more efficient water

use technologies) on urban residential water use. The

study covered single-family residential use during 1989

to 1996, a time period incorporating the recent drought

and allowing evaluation of actions taken by water purveyors to reduce residential water use during the

drought. Eight water retailers whose service areas represent 24 percent of California’s population were

included—San Francisco PUC, Marin MWD, Contra Costa WD, East Bay MUD, City of San

Bernardino, City of Santa Barbara, Los Angeles DWP,

and City of San Diego. All of these agencies experienced price increases over the study period and all used

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4A-5 APPENDIX 4A

The California Water Plan Update BULLETIN 160-98 Appendix 4A

non-pricing demand reduction actions during the

study period. Price elasticity was estimated to be -0.16

(meaning that a 10 percent price increase would result

in a 1.6 percent demand reduction) over a range of

marginal prices of $0.47 to $4.25 per hundred cubic

feet, showing that residential demand was price inelastic

over this range.

The urban water demand forecast used for Bulletin 160-98 assumed single-family residential price

elasticities of -0.1 for winter months and -0.2 for summer months. Studies of urban water pricing to date

indicate that the role of pricing by itself in achieving

demand reduction is small. The plot of urban water

production over time shown in Figure 4-4 illustrated

the strong response of water use to the 1987-92

drought. Actions taken by water agencies during the

drought to encourage demand reduction—including

public education programs, voluntary rationing, rebates for plumbing retrofits—decreased residential

water use. However, water use throughout the State is

rebounding to earlier levels, even after significant price

increases by some agencies. For example, Contra Costa

WD increased its average water rates substantially to

finance construction of Los Vaqueros Reservoir. Between 1980 and 1997, CCWD’s average water price

increased by about 217 percent (adjusted for inflation).

Its use per residential unit declined by 9 percent, much

of which is likely due to plumbing retrofit and building code requirements for new plumbing, and public

education.

Agricultural Water Costs

In December 1996, the Department mailed water cost surveys to more than 60 agricultural water

agencies in California. This survey was conducted to

determine the range of average agricultural retail surface water costs in the State and to obtain information

on types of water charges being used. Table 4A-3 summarizes the results of this survey by hydrologic region.

Many responding agencies based their charges on both

water use and number of acres irrigated. The information is presented here to illustrate the variability of

prices based on local circumstances.

Agricultural groundwater costs vary considerably

throughout California. Factors influencing these costs

include depth to groundwater, water quality, and well

yields. Many groundwater users are self-supplied,

meaning that individual water users pump their own

supplies rather than receiving them from a water

agency. Bulletin 160-93 showed general ranges of agricultural groundwater production costs. The

Department does not have sufficient new data to accurately update those general cost ranges for Bulletin

160-98.

Impacts of Price on Agricultural Water Use

Price elasticity of demand for agricultural water is

a measure of farmers’ responsiveness to changes in the

price of water. Researchers have used a variety of models (programming and econometrics) to estimate the

agricultural water use price elasticity in different parts

TABLE 4A-3

DWR Survey of 1996 Agricultural Surface Water Costsa

Region 1996 1996 Costs ($/af) Water Rates Basis (number of agencies)

Total Weighted Max. Min. By Acre By Crop By af Used By Acre Total

Deliveries Average & Acre & af

(taf) Used

North Coast 80 10 12 220103

San Francisco Bayb — — — — — — — — —-

Central Coast 37 128 533 87 00224

South Coast 92 373 604 13100178

Sacramento River 1,275 12 32 214128

San Joaquin River 1,339 22 238620147

Tulare Lake 2,672 42 161 9 1 0 4 6 11

North Lahontanb — — — — — — — — —-

South Lahontan 18 61 61 61 00101

Colorado River 3,403 13 14 820024

Statewide 8,916 ——— 8 4 11 23 46

a

 Average retail costs to the farmer

b No responses

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APPENDIX 4A 4A-6

Appendix 4A The California Water Plan Update BULLETIN 160-98

of the country, and have concluded that demand for

irrigation water is generally price inelastic, within price

ranges typical for agricultural water use. Obviously,

there is no other commodity that can be substituted

for the water needed to grow crops. As Table 4A-4

illustrates, water costs are typically a relatively small

percentage of the total cost of producing most crops.

The Central Valley Production Model was used to estimate agricultural price elasticity in the Central Valley.

CVPM price elasticity estimates for irrigation water

demand are based on the level of production of various crops. CVPM also allows for changes in cropping

patterns as water becomes more scarce, more expensive, or both.

Results of CVPM studies are summarized in Table

4A-5. Surface water prices were increased for the study

by different increments, and groundwater costs increased as a result of changes in pumping depths. Both

short- and long-term elasticities were estimated. In the

short-term study, it was assumed that farmers did not

have enough time to adjust to increases in water costs,

while in the long-term farmers could switch to more

efficient irrigation technologies.

The values in the table are estimates of a farmer’s

ability to respond to water price changes. For example,

if surface water prices increase by 10 percent in the

Sacramento Valley, the demand for surface water will

decline by 3.2 percent. The model runs indicated that

demand for irrigation water was price inelastic over

the price ranges analyzed. Where groundwater is available in the Central Valley, farmers may increase their

groundwater use if pumping costs are less than the costs

of their surface water supplies.

CVPIA Tiered Pricing

Section 3405(d) of CVPIA required that new, renewed, or amended contracts for project water

incorporate an inverted block rate pricing structure

specified in the act. The first rate tier applied to a quantity of water up to 80 percent of the contract total.

The second rate tier applied to the quantity of water

from 80 percent to 90 percent of the water under contract, and was to be halfway between the rate for the

first tier and the third tier. The third tier applied to

the quantity of water beyond 90 percent of the contract total, and was to be not less than USBR’s full cost

rate. USBR’s municipal and industrial customers are

already charged the full cost rate, which includes cost

of service, principal and interest on facility construction costs, and CVPIA Restoration Fund charges.

As noted in Chapter 2, all of USBR’s contract renewals to date have been interim renewals, since the

PEIS required by the act has not yet been completed.

No long-term renewal contracts can be executed until

USBR completes the PEIS, which is now expected to

occur in 1999. Through 1996, interim contracts for

project water supply represented about 16 percent of

project water under contract.

In its 1998 public draft PEIS, USBR used CVPM

to estimate potential impacts of implementing tiered

pricing as set forth in the act. USBR estimated that

implementing tiered pricing would reduce average year

CVP applied irrigation water in the CVP service area

TABLE 4A-4

Average Water Costs as a Percent of Total

Production Costs for Selected Crops in

the Tulare Lake Regiona

Crop Water Costs as a Percent

of Total Costs

Irrigated pasture 36

Alfalfa hay 19

Barley 16

Dry beans 14

Wheat 14

Cotton 12

Sugar Beets 12

Safflower 11

Dry Onions 9

Almonds 6

Pistachios 6

Processing tomatoes 6

Wine grapes 5

a

 Data from output of the Department’s Central Valley Net Crop

Revenue Model.

TABLE 4A-5

Price Elasticities for Surface Water Irrigation Demand

Region Short-Term Elasticity Long-Term Elasticity Range of Water Prices ($/af)

Sacramento River -0.24 -0.32 20 - 240

San Joaquin River -0.20 -0.30 20 - 240

Tulare Lake -0.18 -0.24 20 - 240

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4A-7 APPENDIX 4A

The California Water Plan Update BULLETIN 160-98 Appendix 4A

by 266 taf from CVPIA’s assumed no-action condition. This amount took into consideration the shift

from CVP water use to groundwater use, in those areas having access to groundwater supplies. (The

estimate assumed that USBR’s ability to pay policy for

irrigation remained in effect for principal on capital

and Restoration Fund charges, at an estimated payment capacity of $11/af north of the Delta and $70/af

south of the Delta.)

USBR also evaluated alternatives to the tiered pricing specified in the act, including an analysis which

assumed that ability to pay provisions were not in force.

This approach would reduce applied irrigation water

by an additional 25 taf in an average water year. The

greatest reduction in applied irrigation water use occurred in USBR’s alternative which exceeded the

requirements of the statute by applying full cost pricing to the first 80 percent of contract water supply,

110 percent of full cost pricing to the second tier, and

120 percent of full cost pricing to the last 10 percent

of contract water supply. The draft PEIS estimated that

this alternative would reduce applied irrigation water

by about 570 taf in an average year.

After USBR completes the CVPIA PEIS, longterm contract renewals can begin. The effects of tiered

pricing on CVP water use will be manifested over time,

as more contracts are renewed. The relationship of CVP

tiered pricing to CVP water use, however, cannot necessarily be generalized to price/water use relationships

for agricultural users served from non-USBR sources.

Agricultural water users served by the SWP, local water projects, and self-supplied sources already pay full

cost rates for their supplies.

Comparing Agricultural and Urban

Water Costs

Generally, agricultural water supply costs are lower

than urban costs. Much of the State’s earliest largescale water development was for agriculture, and the

irrigation works were constructed when water development was inexpensive by present standards. Also,

there are basic differences in the delivery systems providing agricultural and urban water supplies. The price

of water is determined by the cost of water at the source

(from a reservoir or at the Delta, for example) plus the

costs of using the facilities associated with conveying,

storing, treating, and delivering the water to the final

users. Some contracts for agricultural supplies have

allowed agricultural users to pay a lower price for water supplies in return for accepting supplies with a lower

level of reliability. Typically this was achieved by

deficiency provisions incorporated in the water

supply contracts.

Both urban and agricultural water agencies must

pay transportation costs incurred to bring the water

supplies to their service areas. However, agricultural

agencies are often closer to the surface water sources

and in many cases are able to rely on gravity-operated

conveyance and distribution systems, avoiding energy

costs associated with pressurized pipelines. Urban water supplies often travel through hundreds of miles of

canals or pipelines, adding considerably to the transportation costs. For example, by 2000, power costs to

deliver SWP water to the San Joaquin Valley service

area are estimated to be about $15/af. Power costs to

deliver the same acre-foot of SWP water to the South

Bay, Central Coast, and Southern California service

areas are estimated to be about $34, $78, and $87,

respectively.

Urban water systems have additional delivery costs

compared to agricultural systems. For example, urban

water users must pay for terminal storage and pressurization of water. Monitoring and treating water for

public health protection is expensive, and costs are expected to increase as a result of more stringent drinking

water standards. Most urban water systems also incur

substantial costs to install and read meters, and to prepare billings.

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4A 4A-8

Appendix 4A The California Water Plan Update BULLETIN 160-98

EE-RM-PET-100 C0MMENT 01A
4B-1 APPENDIX 4B

The California Water Plan Update BULLETIN 160-98 Appendix 4B

Sc,w,t = Uw,t * Rc,w * Pc,w,t

where

Sc,w,t = water savings resulting from the implementation of conservation measure c, in water use category w, at time t, expressed in gallons per day

Uw,t = base year water use in water use category w at time t, expressed in gallons per capita

per day

Rc,w = reduction in water consumption resulting from the implementation of conservation measure c, in water use category w, expressed as a proportion of base year water

use

Pc,w,t = population affected by conservation measure c, in water use category w, at time t

BMP Revisions and

Water Savings Assumptions

Table 4B-1 provides a synopsis of revisions to urban water conservation BMPs, as

adopted by CUWCC in September 1997.

Table 4B-2 summarizes BMP water savings assumptions specified in the Urban MOU.

These assumptions served as the basis for urban water use study conservation savings calculations, according to the following general formula:

4B

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4B 4B-2

Appendix 4B The California Water Plan Update BULLETIN 160-98

1 Water Survey Programs

for Single-FamilyResidential andMultifamily ResidentialCustomers

Removes requirement tospecifically target top 20% ofresidential water users. Allowsagencies to develop targetingand marketing approachestailored to their service areas.Specifies minimum auditelements. Requires agencies todevelop database to trackprogram.

Extends the implementationschedule 10 years from thedate the BMP is revised or thedate an agency signs theMOU, whichever is later.

Replaces the requirement that70% of the top 20% ofresidential customers accept anaudit by September 1, 2001,with the requirement that15% of residential customersaccept an audit within 10

years

of the date of implementationfor the agency.

Requests similar types andamounts of information ascurrently being collected inCUWCC annual reports.

2 Residential Plumbing

Retrofit

Adds requirement thatagencies maintain devicedistribution programs at levelssufficient to distribute retrofitkits to not less than 10% ofresidential accounts eachreporting period until coveragerequirement is met. Allowsagencies to use massdistribution methods asappropriate. Allows agencies todevelop targeting andmarketing approaches tailoredto their service areas. Requiresagencies to develop data baseto track program.

Replaces the requirement thatagencies realize the coveragerequirement by September 1,2001, with the requirementthat they maintain theprogram at specified level untilthey can demonstrate coveragerequirement is met.

Replaces the requirement that75% of single-family and 80%of multifamily residencesconstructed prior to 1980 areretrofitted with therequirement that 75% ofsingle-family and multifamilyresidences constructed prior to1992 are retrofitted.

Requests similar types andamounts of information ascurrently being collected inCUWCC annual reports.

TABLE 4B-1

BMP Revisions

Changes to Existing BMP Definitions, Implementation Schedules, Coverage

Requirements, and Reporting Requirements Contained in Exhibit 1 of the MOU

BMP BMP Name Changes to Changes to Changes to Changes to Reporting

Number BMP Definition Implementation Schedule Coverage Requirement Requirement

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4B-3

APPENDIX 4B

The California Water Plan Update BULLETIN 160-98 Appendix 4B

3 System Water Audits,

Leak Detection andRepair

Replaces requirement thatagencies conduct a completesystem audit every three yearswith requirement that agenciesconduct annual pre-screenaudits and conduct full systemaudits only if indicated by thepre-screen audit.

Makes implementationschedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later.

No change. Requests similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

4 Metering with

Commodity Rates forAll New Connectionsand Retrofit of ExistingConnections

Adds requirement thatagencies assess feasibility ofprogram to retrofit mixed-usemetered accounts withdedicated irrigation meters.

Makes implementationschedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later. Extendsdate that coverage requirementmust be met from September1, 2001, to 10

years from the

date the BMP is revised or thedate an agency signs theMOU, whichever is later.

No change. Requests similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

TABLE 4B-1

BMP Revisions

Changes to Existing BMP Definitions, Implementation Schedules, Coverage

Requirements, and Reporting Requirements Contained in Exhibit 1 of the MOU (continued)

BMP BMP Name Changes to Changes to Changes to Changes to Reporting

Number BMP Definition Implementation Schedule Coverage Requirement Requirement

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4B 4B-4

Appendix 4B The California Water Plan Update BULLETIN 160-98

5 Large Landscape

Conservation Programsand Incentives

Adds requirement thatagencies develop water usebudgets for accounts withdedicated irrigation meters.Removes requirement tospecifically target landscapes of3+ acres for audits. Continuesto require audits for customerswithout landscape water usebudgets. Continues to requirecustomer incentive programs.Allows agencies to developtargeting and marketingapproaches tailored to theirservice areas. Requires agenciesto develop database to trackprogram.

Makes implementationschedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later. Allowsagencies 10 years from dateBMP implementation is to beunderway to meet coveragerequirement. Allows agenciesfour years to develop water usebudgets for dedicatedirrigation meter accounts.

Removes requirement thatagencies offer audits to 100%of accounts with 3+ acres oflandscape by September 1,2001. Adds requirement thatagencies provide landscapeaudits to 15% of mixed-use,non-residential accountswithin 10 years from dateBMP implementation is to beunderway for agency. Addsrequirement that agencies offeraudits to not less than 20% ofmixed-use, non-residentialaccounts each reportingperiod. Allows agencies tosatisfy audit requirements byimplementing a mixed-usemeter retrofit program or aprogram to develop landscapewater use budgets for accountswith mixed-use meters.

Requests data on the number ofaccounts with dedicated irrigationmeters, and number of waterbudgets established duringreporting period. Otherwise,requests similar types andamounts of information ascurrently being collected inCUWCC annual reports.

TABLE 4B-1

BMP Revisions

Changes to Existing BMP Definitions, Implementation Schedules, Coverage

Requirements, and Reporting Requirements Contained in Exhibit 1 of the MOU (continued)

BMP BMP Name Changes to Changes to Changes to Changes to Reporting

Number BMP Definition Implementation Schedule Coverage Requirement Requirement

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4B-5 APPENDIX 4B

The California Water Plan Update BULLETIN 160-98 Appendix 4B

6

(New)

High-EfficiencyWashing MachineRebate Programs

Adds requirement thatagencies offer maximum costeffective customer rebate forhigh-efficiency washingmachines if energy serviceprovider in service area is alsooffering rebates.

7 Public Information

Programs

Adds requirement thatagencies conduct publicawareness surveys every threeyears to assess conservationattitudes and guide programdesign.

Makes implementationschedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later.

No change. Requests similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

8 School Education

Programs

No substantive changes. Makes implementation

schedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later.

No change. Requests similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

9 Conservation Programs

for Commercial,Industrial, andInstitutional Accounts

Replaces audit requirementwith a two track approach. Anagency can choose either toimplement an audit programfor CII customers, or to meet awater savings performancetarget for the CII sector.Requires CUWCC to developlong-term CII ULFTimplementation targets basedon findings of CUWCC CIIULFT water savings studywithin one year of BMPadoption.

Makes implementationschedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later. Allowsagency 10 years from dateBMP implementation is to bestarted to begin meetingcoverage requirement.

Requires either 10% ofcommercial, industrial, andinstitutional accounts toaccept an audit within 10

years

or a reduction in water use bycommercial, industrial, andinstitutional accounts by anamount equal to 10% of theuse by the top 10% ofaccounts.

Requires agencies to substantiateeither completed audits or watersavings estimates. Requestssubstantially more information onprogram design andimplementation than what iscurrently being collected throughCUWCC annual reports.

TABLE 4B-1

BMP Revisions

Changes to Existing BMP Definitions, Implementation Schedules, Coverage

Requirements, and Reporting Requirements Contained in Exhibit 1 of the MOU (continued)

BMP BMP Name Changes to Changes to Changes to Changes to Reporting

Number BMP Definition Implementation Schedule Coverage Requirement Requirement

N/A N/A N/A

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4B 4B-6

Appendix 4B The California Water Plan Update BULLETIN 160-98 10 (New) Wholesale Agency Assistance Programs Defines wholesale agency support roles in terms of financial, technical, and programmatic assistance to retail agencies implementing BMPs. Makes implementation schedule relative to the date the BMP is revised or the date an agency signs the MOU, whichever is later. Requires wholesalers to justify financial, technical, and programmatic support levels. Requires additional reporting by wholesale agencies over what is currently being collected through CUWCC annual reports. 11 Conservation Pricing Retains current definitions of non-conserving and con- serving rate structures. Adds requirement that CUWCC undertake a study to empirically assess the affect of rate structure on customer water use patterns and quantities, and to specifically examine the relationship between customer demand and the proportion of agency revenue requirement recovered through commodity charges, fixed charges, and other service charges. Makes implementation schedule relative to the date the BMP is revised or the date an agency signs the MOU, whichever is later. No change. Requests similar types and amounts of information as currently being collected in CUWCC annual reports.

12

(formerly

BMP 14)

ConservationCoordinator

No substantive change. Makes implementation

schedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later.

No change. Requests similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

TABLE 4B-1

BMP Revisions

Changes to Existing BMP Definitions, Implementation Schedules, Coverage

Requirements, and Reporting Requirements Contained in Exhibit 1 of the MOU (continued)

BMP BMP Name Changes to Changes to Changes to Changes to Reporting

Number BMP Definition Implementation Schedule Coverage Requirement Requirement

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4B-7

APPENDIX 4B

The California Water Plan Update BULLETIN 160-98 Appendix 4B

13 Water Waste

Prohibition

No substantive change. Makes implementation

schedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later.

No change. Requires similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

TABLE 4B-1

BMP Revisions

Changes to Existing BMP Definitions, Implementation Schedules, Coverage

Requirements, and Reporting Requirements Contained in Exhibit 1 of the MOU (continued)

BMP BMP Name Changes to Changes to Changes to Changes to Reporting

Number BMP Definition Implementation Schedule Coverage Requirement Requirement

 14

(formerly

BMP 16)

Residential ULFTReplacement Programs

Removes reference to CIIULFT replacementrequirements; otherwise nosubstantive change.

Makes implementationschedule relative to the datethe BMP is revised or the datean agency signs the MOU,whichever is later. Allowsagency 10 years from dateimplementation is tocommence to meet coveragerequirement.

No change. Requests similar types and

amounts of information ascurrently being collected inCUWCC annual reports.

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4B 4B-8

Appendix 4B The California Water Plan Update BULLETIN 160-98

TABLE 4B-2

BMP Water Savings Assumptions

BMP BMP Name MOU Savings Assumptions Urban Water Use Study

Number Coverage Requirement Reduction Factor Modeling Assumptions

1 Water Survey Programs for SingleFamily and Multifamily Customers 15% of residential accounts. Pre-1980 Construction Shower head replacement: 7.2 gpcd

Toilet retrofit: 1.3 gpcdLandscape Audit: 10% of outdoor usePost-1980 ConstructionShower head replacement: 2.9 gpcdToilet retrofit: 0 gpcdLandscape Audit: 10% of outdoor use

Modeled based on MOUsavings assumptions.

2 Residential Plumbing Retrofit 75% of single-family and multifamily

residences.

Pre-1980 ConstructionShower head replacement: 7.2 gpcdToilet retrofit: 1.3 gpcdPost-1980 ConstructionShower head replacement: 2.9 gpcdToilet retrofit: 0 gpcd

Modeled based on MOUsavings assumptions.

3 System Water Audits, Leak Detection,

and Repair

Maintain active distribution systemauditing program and repair systemleaks when cost-effective.

Unaccounted water losses assumed tobe no more than 10% of total waterinto the suppliers’ system.

Not modeled because statewideaverage unaccounted water losscurrently meets the MOU targetvalue.

4 Metering with commodity rates for all

new connections and retrofit of existingconnections

100% of unmetered accounts to bemetered and billed by volume of use.

20% reduction in demand byretrofitted accounts.

Modeled based on MOUsavings assumptions.

5 Large Landscape Conservation

Programs and Incentives

ET

o - based water use budgets for 90%

of accounts with dedicated irrigationmeters; irrigation water use surveys for15% of CII accounts with mixed usemeters.

15% reduction in irrigation waterdemand for surveyed landscapes.

Not modeled due to insufficientbase year data on landscapewater use and acreage.

6 High-Efficiency Washing Machine

Rebate Programs

Cost-effective customer incentive forthe purchase of high-efficiency washingmachines to be offered if incentives arebeing offered by local energy provideror wastewater utility.

Not quantified at this time. Not modeled due to “not

quantified” status in MOU.

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4B-9 APPENDIX 4B

The California Water Plan Update BULLETIN 160-98 Appendix 4B

TABLE 4B-2

BMP Water Savings Assumptions (continued)

BMP BMP Name MOU Savings Assumptions Urban Water Use Study

Number Coverage Requirement Reduction Factor Modeling Assumptions

7 Public Information Programs Maintain an active public information

program to promote and educatecustomers about water conservation.

Not quantified. Not modeled due to “not

quantified” status in MOU.

8 School Education Programs Maintain an active school education

program to educate students inagencies’ service areas about waterconservation and efficient water uses.

Not quantified. Not modeled due to “not

quantified” status in MOU.

9 Conservation Programs for

Commercial, Industrial, andInstitutional Accounts

10% of CII customers to accept a wateruse survey or reduce water use by CIIcustomers by an amount equal to 10%of baseline CII water use.

Commercial Water Use12% reduction in water use (gallonsper employee per day) occurring from1980-2000.Industrial Water Use15% reduction in water use (gallonsper employee per day) occurring from1980-2000.

Modeled based on MOUsavings assumptions.Modeled based on MOUsavings assumptions.

10 Wholesale Agency Assistance Programs Report on cost effectiveness of each

BMP the agency is potential obligatedto support, agency avoided cost peracre-foot of new water supplies,monetary value of financial incentiveand resources provided to retailmembers to assist or support BMPimplementation, and amount ofverified water savings achieved by eachwholesaler-assisted BMP.

Not quantified. Not modeled due to “not

quantified” status in MOU.

11 Conservation Pricing Maintain rate structure consistent with

the definition of conservation pricingspecified in the MOU.

Not quantified. Although not quantified by the

MOU, this BMP was modeledon the basis of DWR waterprice forecasts and recent studiesof urban water price elasticity inCalifornia.

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4B 4B-10

Appendix 4B The California Water Plan Update BULLETIN 160-98

TABLE 4B-2

BMP Water Savings Assumptions (continued)

BMP BMP Name MOU Savings Assumptions Urban Water Use Study

Number Coverage Requirement Reduction Factor Modeling Assumptions

12 Conservation Coordinator Maintain and staff the position of

conservation coordinator and providesupport staff as necessary.

Not quantified. Not modeled due to “not

quantified” status in MOU.

13 Water Waste Prohibition Adopt water waste prohibitions

consistent with the provisions specifiedin the MOU for this BMP.

Not quantified. Not modeled due to “not

quantified” status in MOU.

14 Residential ULFT Replacement

Programs

Savings to equal or exceed watersavings achievable through anordinance requiring the replacement ofhigh water using toilets with ULFTsupon resale.

At least as effective as requiring toiletreplacement at the time of resale.(Exhibit 6 of the MOU presents adetailed methodology for estimatingsavings).

Modeled based on MOUsavings assumptions.

EE-RM-PET-100 C0MMENT 01A
4B-11 APPENDIX 4B

The California Water Plan Update BULLETIN 160-98 Appendix 4B

EE-RM-PET-100 C0MMENT 01A
4C-1 APPENDIX 4C

The California Water Plan Update BULLETIN 160-98 Appendix 4C

4C

Normalizing Urban Water Use Data

Some of the public comments the Department

received on the draft Bulletin 160-98 dealt with how

normalized urban water use data were developed and

why normalized data differed from actual water production data. This appendix is provided to address

those comments.

Bulletin 160-98 estimates of urban water use begin with raw data from the Department’s survey of

public water systems. This survey provides local agencies’ annual water production which, when combined

with population data, can be shown as agency per capita

water production. For each of the Bulletin 160 DAUs

(or in some cases, PSAs) representative water purveyors are selected, and their production data are

quality-controlled to fill in missing data points, check

production numbers, and resolve inconsistencies in the

data.

Figure 4-4 in Chapter 4 showed how average statewide urban water production has varied over time.

Information used to prepare the figure came from the

public water systems surveys. Figure 4C-1 shows

sample data for 12 cities or water agencies, to illustrate geographic variability in production, together with

statewide average water production. These plotted data

do not include self-produced water, water that is developed by entities for their own use. Most

self-produced water is developed by industrial users.

The Department estimates quantities of self-produced

water through periodic surveys of industrial water users.

Statewide, the residential sector accounts for over

half of total urban water use. The landscape component of residential (and some commercial and

institutional) use strongly influences year-to-year variations in urban use, reflecting availability of precipitation

and other water sources. Landscape water use increases

in dry years in most parts of the State, if water supplies

are available, since less precipitation occurs. Regional

variations in landscape water use reflect climatic differences and the extent to which available water supplies

depend on local precipitation or on supplies from other

sources.

FIGURE 4C-1

Sample Urban Water Production Data

0

50

100

150

200

250

300

350

400

450

1980 1985 1990 1995

Gallons Per Capita Daily

Bakersfield

CCWD

EBMUD

Statewide Fresno

Average

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4C 4C-2

Appendix 4C The California Water Plan Update BULLETIN 160-98

Addressing the impacts of the 1987-92 drought

was a major consideration in reviewing the water purveyor data used for Bulletin 160-98. As shown in Figure

4-4, statewide average urban per capita water production declined during the drought years due to water

rationing and other short-term restrictions in use, but

then began to rebound. Capturing this rebound effect

was important to estimating 1995 normalized urban

use for Bulletin 160-98. As described in Chapter 4,

the normalizing process is intended to remove water

use irregularities due to droughts, extremely wet years,

or other conditions. Calendar year 1995 was a wet year.

Actual urban water production data for 1995 are thus

lower than the Bulletin 160 normalized urban water

use data.

Normalized urban water use is calculated for each

DAU, except in the sparsely populated desert areas in

southeastern California, where calculations are done

at a PSA level. Recent production data from representative water purveyors are combined with normal water

supplies and water use patterns to produce a composite per capita water production value for each DAU.

Data for years during and immediately following the

drought are removed from consideration due to the

effects of water shortages of unprecedented severity and

duration and a multi-year rebound in per capita water

FIGURE 4C-1

(continued)

FIGURE 4C-1

(continued)

0

50

100

150

200

250

300

350

400

450

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

Victor Valley

County WD

Santa Barbara

San Diego

San Francisco

S ta tewide

Average

0

50

100

150

200

250

300

350

400

450

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

S ta tewide

Average

Sacramento

Marin MWD

LADWP

San Bernardino

EE-RM-PET-100 C0MMENT 01A
4C-3 APPENDIX 4C

The California Water Plan Update BULLETIN 160-98 Appendix 4C

use. The composite per capita water production value

is adjusted to account for self-produced water supplies,

permanent effects of urban BMPs, and post-1990

changes to federal and State plumbing fixture standards to result in base year per capita water use.

The amount by which a normalized value differs

from actual production data for a given year varies from

DAU to DAU, as shown in Figure 4C-2 for some

sample DAUs. (The 1995 statewide average normalized per capita urban water use was 229 gpcd, of which

9 gpcd represented self-produced water.) Normalized

per capita water use data (water purveyor production

plus self-produced water) are multiplied by the corresponding population to arrive at base 1995 normalized

urban water use for each DAU. When DAU-level information is combined into hydrologic regions for

Bulletin 160 water budgets, the “other” component of

urban water use is added to the regional water budgets. This “other” component is small in comparison

and includes recreation water use, energy production

water use, and losses from major conveyance facilities.

(With the addition of the “other” component, total

1995 normalized statewide average per capita water

use is 244 gpcd.)

San Jose DAU 44

Orange DAU 96

FIGURE 4C-2

Actual and Normalized Production Data

0

50

100

150

200

250

300

350

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

Actual

1 9 9 5

Av e ra g e Ye a r

( No r m a l i z e d )

+

0

50

100

150

200

250

300

350

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

1 9 9 5

Av e ra g e Ye a r

( No r m a l i z e d )

+

Actual

EE-RM-PET-100 C0MMENT 01A
APPENDIX 4C 4C-4

Appendix 4C The California Water Plan Update BULLETIN 160-98

0

50

100

150

200

250

300

350

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

1 9 9 5

Av e ra g e Ye a r

( No r m a l i z e d )+

Actual

Placer DAU 172

FIGURE 4C-2

(continued)

0

50

100

150

200

250

300

350

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

1 9 9 5

Av e ra g e Ye a r

( No r m a l i z e d )

+

Actual

Oakland DAU 47 (Alameda County portion)

Fresno DAU 233

0

50

100

150

200

250

300

350

1980 1985 1990 1995

G a l l o n s P e r C a p i t a D a i l y

Includes 29 gpcd self-produced industrial water use not accounted for in the plot of actual production data.

1 9 9 5

Av e ra g e Ye a r

( No r m a l i z e d )

+

Actual

a

a

EE-RM-PET-100 C0MMENT 01A
4C-5 APPENDIX 4C

The California Water Plan Update BULLETIN 160-98 Appendix 4C

EE-RM-PET-100 C0MMENT 01A
5-1 TECHNOLOGY IN WATER MANAGEMENT

The California Water Plan Update BULLETIN 160-98

Technology In

Water Management

This chapter highlights the present status and anticipated development

of water management technologies. Review of water management technologies provides an important foundation for evaluating water

management options described in later chapters of the Bulletin. For example, it is a common public perception that seawater desalting will solve most of California’s future water

problems. However, the current and reasonably foreseen state of desalting technology suggests that it will be used to meet relatively small, specialized needs due to its high cost. This

chapter presents some case histories of selected technology applications and illustrates a

few innovative examples.

Demand Reduction Technologies

Technological advances have improved urban and agricultural water use efficiency

throughout the State. Future advances are expected to affect landscape irrigation, residential

indoor water use, interior commercial, institutional, and industrial

water use, and agricultural water use. Since the purpose of the

Department’s Bulletin 160 series is to assess water supply benefits, it is

that aspect of demand reduction that the Bulletin addresses. Demand

reduction technologies may provide additional benefits, such as reducing

water treatment costs, reducing fish entrainment at water supply

The city of Santa

Barbara’s desalter

was operated

during the drought

in 1992 and is now

on standby status.

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TECHNOLOGY IN WATER MANAGEMENT 5-2

The California Water Plan Update BULLETIN 160-98

diversion structures, or reducing nonpoint source runoff. These other benefits are recognized in the Bulletin’s

options evaluation process, as described in Chapter 6.

Landscape Irrigation Technology

New irrigation control system technology can save

water by setting irrigation cycles to account for changes

in such factors as soil moisture and ET. New technology includes both retrofit devices and redesigned

irrigation controllers.

Residential landscape irrigation systems often include sophisticated control devices such as electronic

timers and electric solenoid-controlled valves. This

increased sophistication does not always translate into

water savings because homeowners often lack information on landscape plant water requirements.

Consequently, many residential irrigation timers are

permanently set to meet maximum summer season

water requirements. A 1997 study by Utah State University showed that significant water savings could be

achieved by retrofitting existing residential irrigation

control systems with inexpensive (about $100) soil

moisture-sensing devices. The devices are placed inline between the existing timer and valves and override

a planned irrigation cycle when adequate soil moisture is available. Study results showed that the devices

reduced landscape irrigation water use by an average

of 10 percent. Follow-up questionnaires revealed that

over 70 percent of the study participants observed that

their lawns were as green or greener than before installation of the device.

New irrigation system controllers for the commercial, industrial, and institutional sectors are

programmed for irrigation schedules based on normal

year ET rates, and are adjustable to account for deviations from normal year ET. Some of the most advanced

controllers can be automatically adjusted to current

ET rates using telecommunication pager technology

to access weather data from automated weather stations. Rainfall sensors represent an inexpensive method

to automatically terminate irrigation controller programs during precipitation.

Residential Indoor Water Use Technology

Technological advances in residential indoor water use efficiency have come primarily from redesigning

plumbing fixtures to meet new State and federal standards. Future efficiencies will come from improved

fixtures and installation of more water-efficient home

appliances. In addition, new technology to characterize residential water use may yield data allowing more

accurate forecasts of components of urban water demand. This information would help allocate demand

reduction program resources.

Previously, the breakdown of residential water use

was estimated from water meter data and assumptions

about the water use of various fixtures and appliances.

However, a 1995 study in Boulder, Colorado, showed

that detailed information on water use patterns could

be gathered through analysis of data obtained from

data loggers attached to residential water meters. The

traces have sufficient detail to identify flow signatures

of individual fixtures and appliances. The technique

also provides information to differentiate between indoor and outdoor water use. Based on the success of

the Boulder study, a larger study was organized by the

American Water Works Association Research Foundation. The goal of this study is to collect information

from 1,200 homes in 12 cities, for two 2-week periods—one period in the winter and another in the

summer. The information will be sorted into its major

end use components: toilets, showers, baths, faucets,

dishwashers, washing machines, and leaks. Preliminary

results are shown in Table 5-1. These data will be combined with information from a survey of study

participants to construct a residential water use model.

A final report on the study is scheduled for publication in 1999.

Plumbing Fixtures. State law requires all toilets

sold or installed in California to use no more than

1.6 gallons per flush. These standards have pushed traditional gravity operated toilets to the limit of

acceptable operation. The performance of gravity operated toilets is limited to the flow rate achieved

through the bowl under the force of gravity, placing a

limit on the potential for reducing the amount of water used in each flush.

Pressure-assisted toilets use pressurized flow, in

conjunction with siphon action, to give acceptable

TABLE 5-1

Distribution of Residential Indoor Water Use

Component Average Use (%)

Toilet 26

Washing Machines 23

Shower/Bath 20

Faucets 15

Leaks 13

Dishwasher 1

Other Uses 2

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5-3 TECHNOLOGY IN WATER MANAGEMENT

The California Water Plan Update BULLETIN 160-98

High efficiency horizontal axis washing machines are being

used in commercial applications, but are just becoming

available for home use. A check of large appliance dealers in

1998 showed that two brands of horizontal axis washers were

commonly in stock, at prices ranging from $700 to $1,100.

Comparable standard washers cost from $100 to $600 less.

Some utilities are offering their customers rebates on the

order of $100 to $150 for purchasing the horizontal axis

machines.

operation with less flushing water. The increased flow

rate (more than 70 gpm compared to about 25 gpm

for gravity designs) provides greater force to remove

solids from the bowl and hastens the start of the siphon action. In addition, the surge of water from a

pressure-assisted toilet is more effective at pushing waste

through the drain line.

In the past, use of pressure-assisted technology was

limited to the commercial sector due to high costs and

increased noise. Current residential designs are less

expensive than previous models and only slightly

noisier than gravity toilets. Pressure-assisted toilets

range in price from $220 to $815, compared to $65

to $575 for gravity toilets. Future residential designs

may use 0.5 gallons or less per flush.

Washing Machines. Horizontal-axis washing

machines (front loading washing machines) use significantly less water than traditional vertical-axis,

central agitator machines. Rather than fully immersing the clothes, the tub of the washer rotates through

a horizontal axis in alternating directions to lift and

tumble the clothes through a pool of water. Recent

studies show that these washers use about 25 to 35 percent less water than central agitator models.

Currently, horizontal axis washing machines produced by American manufacturers range in price from

about $700 to $1,100. Models by some European

manufacturers are considerably more expensive. Prices

are expected to decrease to within about $200 of central agitator models as the market grows. A recent

survey of appliance retailers showed the residential market for front loading washers could increase from about

2 percent at present to between 5 to 20 percent over

the next five years.

Water Heaters. Hot water demand systems save

water by either eliminating the need to drain cold water

sitting in the pipe between the water heater and the

plumbing fixture, or by reducing the distance between

the heater and fixture. Demand systems are designed

in two basic configurations: central storage tank and

tankless systems. Central storage tank systems are based

on traditional water heater and plumbing systems,

modified with the addition of a valve to open a loop

back to the hot water tank, and a pump to push the

cold water back to the water heater while drawing hot

water into the pipe. When hot water reaches the fixture, the loop closes and the hot water exits the fixture.

Tankless systems, also known as instantaneous or ondemand water heaters, heat water only when needed.

They can be located near the plumbing fixture to reduce the amount of cold water that must be displaced

for hot water to reach the fixture. Because they do not

store hot water, tankless systems save energy by eliminating standby losses.

Water savings depend on the amount of water to

be displaced before hot water reaches the fixture (or

the amount of water that would have been displaced,

in the case of tankless systems). Measurements by the

California Energy Commission show that about two

times the pipe volume between the water heater and

the fixture must be replaced before hot water reaches

the fixture, due to heat lost to the pipe. A 1996 study

of potential water savings in Southern California

showed that hot water demand systems could save approximately 30 gpd per unit.

Interior CII Water Use Technology

Plumbing Fixtures. The water savings potential

of 0.5 gpf toilets also applies to the commercial sector.

In addition, while State law requires that urinals use

no more than an average of 1.0 gpf, this water requirement could be further reduced or eliminated through

the use of waterless urinals. Waterless urinals attach to

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TECHNOLOGY IN WATER MANAGEMENT 5-4

The California Water Plan Update BULLETIN 160-98

standard plumbing stubs, but require no flushing water to operate.

Water savings from waterless urinals depends on

the frequency of use and the flushing water requirement of the fixture that is replaced. A 1996 study in

Southern California showed potential savings from

about 11 gpd per fixture in office buildings to about

55 gpd per fixture in airports and movie theaters. In

1995, the U.S. Navy equipped sample bathroom facilities at the Naval Air Station North Island in San

Diego with waterless urinals. The study found that

replacement saved about 45,000 gallons of water per

year, with a pay-back period of about 3 years. Based

on the success of the trial, more than 200 waterless

urinals were installed at the station. To date, the urinals remain in operation and perform well when

maintained according to manufacturer recommendations.

Cooling Towers. The largest use of water in the

industrial sector is for cooling. Water is used to cool

heat-generating equipment, manufactured products,

and food products and containers in canneries. The

most water-intensive cooling method is once-through

cooling, where water contacts and lowers the temperature of a heat source, then is discharged to waste.

Recirculating cooling tower systems reduce water use

by using the same water for several cycles.

The majority of cooling towers in California are

recirculating evaporative systems, where the temperature of the cooling water is reduced through

evaporation. As cooling water is recycled through the

Evaporative cooling towers are used by a wide range of

industries.

tower, the salt concentration increases. Salt build-up

must be managed to avoid scaling on condenser tubes,

which results in reduced heat transfer efficiency.

Blowdown is the release of some of the circulating water

to remove the suspended and dissolved solids left behind due to evaporation. Make-up water is added in

place of the blowdown to reduce the total dissolved

solids. Water savings can accrue by minimizing

blowdown or by converting to a dry cooling process

based on air heat exchangers.

Blowdown can be minimized by treating the recirculating water with sulfuric acid or ozone (to control

scaling and biological fouling), by mechanical filtration of solids, and by the use of conductivity sensors

and automatic valves to precisely control the

blowdown/makeup process. Savings can be maintained

through regular calibration of the conductivity sensors. A 1996 study conducted for MWDSC suggested

that the majority of potential cooling tower water savings in Southern California could be realized through

the addition and/or calibration of conductivity controllers. Water savings estimates ranged from about 400

to more than 900 gpd per site.

Air heat exchangers use fans to blow air past finned

tubes carrying the recirculating cooling water. The

Pacific Power and Light Company’s Wyodak Generating Station in Wyoming uses dry cooling to eliminate

water losses from cooling water blowdown and evaporation. The processed steam is condensed by routing

it through finned carbon steel tubes as fans force air,

at a rate of 45 million cubic feet per minute, through

an 8 million square foot finned-tube surface. This technique results in a water requirement of 300 gpm,

compared to about 4,000 gpm of make-up water for

equivalent evaporative cooling.

Agricultural Water Use Technology

Future technological advances in irrigation systems

and irrigation scheduling are expected to result in more

efficient agricultural water use.

Irrigation Systems. Many terms are used in describing the performance of irrigation systems, but the

two most important are DU and SAE, defined in

Chapter 4. The accompanying sidebar defines several

agricultural technology terms used throughout this section. Irrigation experts generally agree that an

80 percent DU is achievable by all irrigation systems

and is an upper limit for existing systems. With today’s

systems, SAEs of more than 73 percent indicate under-irrigation, potentially resulting in a reduction of

EE-RM-PET-100 C0MMENT 01A
5-5 TECHNOLOGY IN WATER MANAGEMENT

The California Water Plan Update BULLETIN 160-98

crop production and an increase in soil salinization.

Whether a gravity or pressurized system, a well-designed and well-managed irrigation system

appropriate to a field’s terrain, soil, crop, and flow

constraints can achieve the maximum DU and result

in high SAE, provided the irrigation water supply is of

adequate quality and is available when needed at the

proper rate of delivery.

Adoption of new irrigation technology to reduce

applied water must result in a reduction of deep percolation, tailwater runoff, ET, or leaching requirement.

Reduced deep percolation and tailwater runoff could

be achieved by improving in DUs and irrigation management. Evapotranspiration could be reduced by

minimizing losses from surface evaporation, or by intentional underirrigation with no loss in production

or quality. Reducing the leaching requirement (the

amount of water used to leach salts from the soil) is

not a goal because insufficient leaching results in salinization of the soil, rendering it less productive and

consequently reducing water use efficiency.

Gravity, or surface irrigation, systems use the soil

surface to spread and move water on and over a field.

The major types of gravity irrigation systems used in

California—furrows, border-strip, and level basin—

are discussed in the sidebar. The field is optimally

rectangular, with the water entering the field from the

highest side. The water moves over the surface of the

soil, eventually covering the area intended for irrigation, and infiltrates the soil to replenish soil moisture.

The rate of infiltration varies by soil type and time (a

sandy soil has a much higher infiltration rate than a

clay soil). All soils have a maximum infiltration rate at

the beginning of irrigation. The longer the water is in

contact with the soil, the more the infiltration rate decreases; in some soils it decreases to almost zero.

Important factors for achieving high DUs are intake opportunity time and soil infiltration rate. The

IOT varies within an irrigated field. On furrow systems, the part of the field closest to the source of water

usually has the highest IOT. For high DUs, the IOT

within a field must have a high uniformity. In addition, soil will affect the DU. Different soils with the

same IOT will have different infiltration rates. The

more nonhomogeous the soil, the more soil infiltration rates will vary, resulting in a lower DU.

Irrigation timing, applying the correct amount of

water, and having a high DU are important considerations for achieving high SAE. With most surface

systems, the grower must decide how dry the soil can

become (its allowable depletion) before an irrigation

is applied. The grower’s decision is based on the field,

irrigation system design, crop, soil depth, and other

factors. If the soil has an AD of 3 inches, irrigation

should occur when the soil in the field has dried to

that level. The amount of water applied over the field

should be more than 3 inches, because water cannot

be applied with a DU of 100 percent. Irrigating before reaching the AD could result in an over-application

of water, and a lower SAE. Irrigating after reaching

the AD might result in an under-application, and an

overly high SAE, which is not desirable because plant

stress may occur.

Pressurized, or piped, irrigation systems use pipelines and water emission devices to discharge water into

a field and onto or under the soil surface. Water is

pressurized using a pump and is usually passed through

a filter to reduce the chance of clogging the emission

devices. The water is distributed from a main pipeline

system and sub-mains to lateral pipelines in the cropped

field. Water flows from the emission devices as either a

spray or a very small continuous stream. As the water

meets the soil, it infiltrates to replenish soil moisture.

Pressurized systems are very different from surface

systems. The performance of surface systems depends

upon soil infiltration rates, IOT, and the amount of

water applied. With pressurized systems, DU is constant and depends on the hardware design and

maintenance. The DU will not change, unless pipeline leaks or clogging of devices occur, or winds distort

the spray pattern. One of the most important design

considerations for achieving high DUs is pressure regulation, as flow rates change with pressure. Excessive

Definition of Irrigation Terms

• Distribution Uniformity: A measure of the variation

in the amount of water applied to the soil surface

throughout an irrigated area.

• Seasonal Application Efficiency: The water

beneficially used for ETAW and cultural practices

divided by applied water.

• Intake Opportunity Time: The amount of time that

applied irrigation water is in contact with the soil.

• Allowable Depletion: Depth of water needed to bring

soil moisture to field capacity—a measure of how dry

the soil is allowed to become before an irrigation is

applied.

• Reference Evapotranspiration (ETo): The ET of wellwatered 4 to 6 inch tall turf.

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TECHNOLOGY IN WATER MANAGEMENT 5-6

The California Water Plan Update BULLETIN 160-98

pressure variations in the design will result in a low

DU.

The most important considerations for achieving

high SAE with pressurized systems are applying the

correct amount of water during an irrigation, and

maintaining a high DU. Since a pressurized system

can apply any amount of water with the same uniformity, the amount of water needed to replenish the crop

root zone must be determined before the irrigation.

Then the irrigation can be operated for the correct

amount of time to apply the required water. The major types of pressurized irrigation systems used in

California—sprinkler and micro-irrigation—are discussed in the sidebar.

Irrigation Scheduling. All irrigation systems require proper scheduling to achieve high SAEs. To

develop an optimized irrigation schedule, the grower

considers several factors: allowable or desirable crop

water stress, the soil’s water holding capacity within

the crop root zone, water availability and/or delivery

constraints, amount of effective rainfall, and application rate. With this information, along with soil

moisture determinations, plant stress indices, and/or

estimates of crop ET, a grower can develop a water

budget schedule. The water budget compares crop ET

with soil AD, allowing the grower to decide when and

how long to irrigate.

Soil moisture is monitored many ways. Subsurface soil samples can be taken and visually inspected

to estimate the moisture status. Soil moisture can be

estimated with mechanical devices such as tensiometers or with electrical resistance devices such as

gypsum blocks that rely on the change in electrical

conductivity of water in the device. A neutron probe,

another moisture-sensing device, measures the amount

of neutrons reflected from water molecules in the soil.

continued ...

Gravity (Surface) Irrigation Systems

Furrow Systems

Furrow is the most common gravity system, and is used

for field crops, truck crops, trees, and vines. Channels or

corrugations are cut or pressed into the soil of a field, usually

one furrow between planted rows of crops. Efficient furrow

systems have a slight grade, sloping from the head of the field

where water enters the furrows to the bottom of the field.

Water is delivered to the furrows using an earthen ditch and

siphon tubes, gated pipe, or underground piping and above

ground valves. In furrow systems, only the soil in the channel

is wetted. Between 20 to 50 percent of the soil surface in a

furrow irrigated field usually comes in contact with the

irrigation water.

To irrigate sloping furrow systems efficiently, tailwater is

allowed to run off the end of the furrows. A tailwater recovery

system is needed to reapply this water, either on the same

field or on another field. Efficient management requires a

relatively high flow at the beginning of the irrigation, to get

the water down the furrow quickly, then the flow is cut back

to reduce tailwater. With furrow systems, high DUs can be

achieved when the advance time (the time it takes the water

to move from the top of the field to the end) is relatively

short compared to the total time of irrigation.

Furrow systems can be designed and operated to achieve

good SAEs for a range of ADs, except for very small ADs.

The AD changes as the root zone changes. The early season

irrigation of annual crops will not be as efficient as later season

irrigations, because the early season AD would be small

(shallow root depths), while the later season AD would be

large (deep roots). Infiltration rates are typically higher soon

after planting and lower later in the season.

Technologies and actions to optimize DUs and increase

SAEs for furrow systems include:

• Dragging torpedoes (heavy metal cylindrical devices) within

a furrow to smooth and compact the soil surface will

decrease the advance time. This is most effective for early

season irrigations, where the soil surface is rough due to

tillage, and the soil intake rate is high.

• Shortening the length of the furrow will result in decreased

advance time. (Shortening furrows increases the number

of furrows, which can also result in less planted acreage

and an increase in the cost of irrigation.)

• Laser leveling of fields to achieve a uniform slope, and a

steeper slope (if practical), will decrease the advance time.

• Using surge irrigation, a technique where short term

opening and closing of valves provides water to the furrows,

resulting in the water “surging” down the furrow. (This

technique is better suited to some soil types than others.)

This technique will improve the uniformity of IOT in a

furrow. It requires a surge valve designed for this

application, and can easily be automated.

• Reducing the flow rate in each furrow after the water has

reached the end of the furrow is essential to reducing the

amount of tailwater produced.

• Using a properly planned and designed tailwater recovery

system, along with efficiently using the captured tailwater

on the same field or other irrigated fields.

Border-Strip Systems

Border-strip systems are generally used for alfalfa and

pasture, but can be used on field crops and trees and vines. A

field is divided into a number of strips, usually between 20 to

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A side roll, wheel move

sprinkler system.

100 feet wide. Low levees, or borders, divide each strip. Each

strip has a slight slope from the head of the strip to the bottom,

and ideally little or no slope between the sides. Water is

delivered to each strip using an earthen ditch and siphon tubes,

gated pipe, or underground piping and above ground valves.

Usually all the soil surface in the strip, other than that in the

borders, comes in contact with irrigation water.

A relatively large flow of water is directed into each strip

during irrigation. The time it takes for the water to reach the

end of the field is the advance time. When the water is between

60 to 90 percent of the way down the strip, the water is shut

off, and the water already in the strip continues to move down

the strip. The time it takes for the water to recede from the

soil surface (from the top of the strip to the bottom) is the

recession time. To achieve a high DU, the advance time must

be very similar to the recession time, resulting in a uniform

IOT over the strip. Generally, a border-strip system is

designed and operated to have a small amount of tailwater,

which requires a tailwater recovery system for reducing

applied water. Border-strip systems can be designed to

have a high DU and can achieve a high SAE, but only for

a specific AD. Border-strip systems are well suited to crops

with a constant deep root zone, such as alfalfa, pasture, trees,

and vines.

Technologies and actions for border-strip systems to

optimize DUs and increase SAEs include:

• Modify the advance rate to match the recession rate by

adjusting the flow rate, changing border spacing, and using

laser leveling to achieve a uniform slope and minimize cross

slope.

• Use a properly planned and designed tailwater recovery

system, and use the captured tailwater efficiently on the

same field or on other irrigated fields.

Level Basin Systems

Level basin systems can be used on alfalfa, pasture, trees,

vines, and field crops. The size of each basin is variable and

depends upon soil infiltration rate and flow rate of water.

Basins can vary from small (50 x 50 feet) to large (10 or more

acres). There should be little or no slope within a basin.

Earthen berms are built up on all sides of the basin. Water is

delivered into each basin from pipelines and valves for smaller

basins or from lined or unlined ditches with large gates.

Normally, level basins are designed to have no tailwater. To

achieve a high DU, the basin must be level, the flow of water

must be high enough to cover the soil surface in a very short

time (without any soil erosion from the flow), and the soil

should be homogeneous.

Technologies and actions to optimize DUs and increase

SAEs for level basin systems include:

• Use laser leveling to achieve a precise grade.

• Minimize soil variability within a basin. Large basins can

be subdivided into smaller basins with uniform soil

characteristics.

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Moisture content can also be estimated by dielectric

sensors, devices that measure the dielectric content of

a soil.

Plant stress indicator devices include pressure

bombs and infrared thermometers. A pressure bomb

is used to determine the turgor pressure within the

cells of a plant’s leaf, which provides information on

the plant’s moisture status. Infrared thermometers are

hand-held devices used to measure plant canopy temperature. Plants can control water loss by regulating

the stomatal openings in their leaves. Monitoring plant

canopy temperatures with this device aids in determining if crop stress is occurring, and can indicate the status

of soil moisture.

Crop ET estimates are developed using either

evaporation pans or weather information. Class A

evaporation pans are commonly used for measuring

evaporation. The pans, constructed of galvanized steel

or aluminum, are situated in the center of a large irrigated turf area. The pan station includes devices to

measure rainfall, temperature, wind speed, and relative humidity. Evaporation is measured by monitoring

the change in height of the water in the pan. The evaporation readings are multiplied by crop coefficients to

estimate ET of a specific crop.

Many growers use automated weather station data

for determining crop ET, such as the California Irrigation Management Information System. CIMIS is a

continued...

Pressurized (Piped) Irrigation Systems

Sprinkler Systems

Sprinkler systems are the most common type of pressurized

systems and can be used for almost all crops. There are many

different sprinkler head designs with flow rates that can vary

from 10 gpm to less than 1 gpm. The spacing of the sprinkler

heads in the field depends upon the flow rates and the radius

of the area where the spray contacts the soil. To achieve high

DUs, systems for field and truck crops are designed to space

sprinkler heads close enough so that there is the proper

amount of overlap of their wetted areas. Sprinkler systems

for tree crops do not generally depend on overlap.

To achieve high DUs, a system must be designed to have

minimal pressure variation, which ensures uniform flow rates

from the sprinkler heads. Sprinkler nozzles must be

maintained, because clogged or partially clogged nozzles lower

DU, and worn nozzles will change flow rates, resulting in

larger variations in pressure in the system. The application

rate must be the same or less than the soil’s infiltration rate.

There are many variations in sprinkler systems used in

California.

Permanent Systems. Permanent systems use underground

pipelines. Risers connect to an underground lateral, usually

with a sprinkler head attached less than a foot from the surface.

These systems are commonly used for orchard irrigation

(under tree), but when connected to taller risers they can be

used for vines.

Solid Set Systems. Solid set systems use above ground

aluminum pipelines, usually in 30 foot sections. Short risers

connect the aluminum laterals to sprinkler heads. With a

solid set system, the irrigation system covers a complete

field. The system may stay in the field for the whole

growing season, and be removed before harvest, or may

be used only for germination or transplant establishment

of vegetable crops. These systems are used mainly for field

and truck crops.

Hand Move Systems. Hand move systems are similar to

the solid set systems, using the same aluminum pipelines,

but do not normally cover a whole field. After an irrigation,

the sprinkler laterals are disconnected from the sub-mains,

and moved by hand to the next location in the field. After

each irrigation, the laterals are systematically moved to the

next location. These systems are usually designed for each

part of the field to receive irrigation water every 7 to 14

days. These systems are used on field crops, truck crops, and

orchards.

Wheeled Systems. Wheeled systems have the lateral, risers,

and sprinkler heads all mounted on wheels that can be moved

throughout the field during the irrigation season. Side roll

systems are designed to be stationary during the irrigation.

After the irrigation, they are moved (using an on-board

engine) to the next location.

Linear Move Systems. Linear move systems have the

lateral, risers, and sprinklers mounted on pipes between large

wheeled towers. The system continuously travels down the

field during irrigations. The water is usually supplied to the

system via a canal parallel to the travel of the system.

Center Pivot Systems. Center pivot systems are similar

in structure to linear move systems, except instead of the

lateral traveling down the field, it travels in a circle in the

field. One end of the lateral is fixed in the middle of the

field, where the water enters the lateral. The entire lateral

rotates around this pivot (which is usually a well), and

continuously moves during irrigations.

Low-Energy Precision Application Systems. LEPA

systems are similar to linear move sprinkler systems, except

that they have drop tubes from the lateral to the soil surface

instead of sprinkler heads. These systems are used in fields

that have furrows, sometimes with small checks or dams in

the furrow. The LEPA system travels perpendicularly to the

furrows, and drop tubes emit water uniformly into the

furrows.

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repository of climatological data collected at 93 computerized weather stations throughout the State.

CIMIS was developed by the Department and the

University of California at Davis, and has been in operation since 1985. Weather data are collected daily

from each weather station site and automatically transmitted to a central computer in Sacramento. Currently,

the CIMIS computer receives over 25,000 requests for

ET data annually, representing approximately

75,000 end users. The weather data (solar radiation,

temperature, relative humidity, and wind speed) are

used with a modified Penman equation to calculate

ETo. ETo is used in irrigation scheduling to estimate plant ET, by multiplying ETo by the

appropriate crop or landscape coefficients.

Regulated deficit irrigation is a technique to reduce crop ET. Irrigation is reduced during a specific

stage of the crop’s growth, resulting in some crop stress

at the time, but with little or no negative effects on

production, quality, or on future growth. Research has

shown that this management technique may be applied to some tree crops such as pistachios, almonds,

Technologies and actions for sprinkler systems to optimize

DUs and increase SAEs include:

• Minimize pressure variation within the system. Design

sprinkler heads, nozzles, and spacings for the proper

amount of overlap in spray. Ensure that application

rates are lower than the soil infiltration rate, and that

filtration is adequate. The sprinkler system must be

properly maintained.

• To avoid spray losses, avoid irrigation during windy

conditions, and ensure that pressures and nozzles are

compatible to avoid misting.

• Where appropriate, use flow control nozzles.

Micro-Irrigation (Low Volume) Systems

Use of these systems increases each year. In many areas

with trees and vines, they are the predominant method of

irrigation. Low volume systems have many of the same

components of sprinkler systems: pressurized water

sources, filters, main pipelines, sub-mains, and laterals.

The main difference is the devices that emit the water to

the soil. These emit water at a very low flow rate (from 0.5

to 10 gallons per hour). There are two types of devices used,

drip and micro-spray. With drip devices (emitters), water flows

out as a constant stream (0.5 to 2 gallons per hour) directly

to the soil. With micro-spray, the devices (spray heads)

produce a spray (4 to 20 gallons per hour) over the soil

surface. Other key differences between micro-irrigation

systems and sprinkler systems are that the entire main

and sub-main pipelines are usually underground rigid

plastic pipe, the laterals are flexible plastic hose, and the

filters are designed to remove much smaller particles to

prevent clogging. Emitter and spray heads use small

orifices, channels, or nozzles to regulate flow rates, and

are subject to clogging by particulate matter and biological

growth.

Drip system emitters are usually spaced 2 to 5 feet apart.

Drip systems can be buried or placed on the soil surface.

Emitter spacing is based upon the soil type being irrigated,

with sandier soils needing a closer spacing, and clay soils using

the greatest spacing. Drip systems are mostly used for orchards

and vines, strawberries, and nurseries, but their use is

increasing for vegetable crops. In these systems, the emitters

are spaced much closer and are installed 8 to 18 inches below

the soil surface.

Micro-spray systems use small plastic sprinklers or jets that

spray water over the soil surface, creating a wetted area 12

feet or more in diameter. The droplet sizes are small compared

to a sprinkler system, and the application rate is low. Microspray heads are connected to plastic lateral hoses, usually one

hose per row of trees. These systems are not designed to wet

the entire soil surface like a typical sprinkler system. These

systems are used almost exclusively in orchards.

Drip and micro-spray systems can achieve high DUs

if pressure variation is minimized. Because of the small

nozzles and emitter pathways, partial or full clogging is

always a potential problem, and can significantly reduce

DU. These systems require regular maintenance to reduce

clogging, including frequent flushing of pipelines and

lateral hoses, and addition of chemicals (such as chlorine

and acids) to kill bacteria and other biological growth and

to reduce scale buildup. The systems require filtration and

the filters need regular maintenance to ensure that they

operate as designed.

Achieving a high SAE with these systems is dependent on

maintaining a high DU and on proper irrigation scheduling.

One advantage to these systems is that irrigation scheduling

is more easily controlled than most sprinkler and surface

systems. Flow can be started and stopped easily (providing

the water delivery system can accommodate this), and

they are easier to automate, even to the extent of using

remotely sensed field information for making irrigation

timing decisions.

Technologies and actions for optimizing DUs and

increasing SAEs of micro-irrigation systems include:

• Ensure that pressure variation within the system is

minimized, the filtration system is adequate, and prevent

emitter clogging.

• Perform regular inspections of filters, emitters/spray heads,

pressure levels, and tubing/pipelines, and provide regular

maintenance, including filter cleaning and hose/pipeline

flushing.

• Where appropriate, use pressure compensating emitters or

microsprinklers.

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and olives. This irrigation strategy may have its greatest value in drought situations, where a grower may be

forced to under-irrigate.

Water Treatment Technologies

As discussed in Chapter 3, water quality is a critical factor in determining the usability and reliability

of any particular water source. Traditional public health

practices emphasize the need to use best available quality sources for municipal supplies and to implement

source protection measures to maintain high quality

raw water sources. Where raw water supplies are of

less than pristine quality, greater reliance must be placed

on treatment technology. Water recycling and desalting are becoming larger components of potential future

supplies, especially for urban areas. To transform these

lower quality raw water sources into reliable water supply options, the basic water treatment technologies

described in this section are used. Application of these

technologies to specific options (such as treating contaminated groundwater) is also outlined.

Description of Water Treatment Technologies

Activated Carbon Adsorption. Treatment by activated carbon adsorption is most applicable to organic

contaminants. By bringing contaminated water in contact with activated carbon in granular or powdered

form, the contaminants are adsorbed onto the carbon.

The process may be accomplished by batch, column,

or fluidized-bed operations. Spent carbon may be regenerated or may be disposed of in accordance with

regulatory requirements. In addition to the traditional

use of activated carbon for taste and odor control and

dechlorination, carbon adsorption is widely used for

removal of volatile organic chemicals and synthetic

organic chemicals.

Granular activated carbon adsorption is a unit

process with a proven ability to remove a broad spectrum of organic chemicals from water. EPA considers

GAC adsorption as the best available technology for

removal of VOCs and SOCs. Powdered activated carbon has traditionally been used to control taste and

odor in water, and is also used for removal of certain

SOCs, especially pesticides. PAC, in combination with

conventional water treatment technology, can provide

acceptable levels of pesticide removal in surface waters. A typical application of PAC would be for seasonal

removal of pesticides found in municipal treatment

plant raw water supplies during wet weather. Some

limitations to use of PAC include the potential need

for large doses of carbon to achieve desired levels of

treatment, and the resultant high sludge production.

Air-Stripping. This treatment technique removes

VOCs from contaminated water. Countercurrent airstripping in a packed tower is the most common

process. The conventional configuration of a unit consists of a tower with water inflow at the top and air

inflow at the bottom. The tower is filled with small

diameter random packing. As clean air moves upward,

the VOCs transfer from the water phase into the air

phase. Treated water exits from the bottom, and the

air containing VOCs is discharged from the top of

the tower, either into the atmosphere or into a gas

treatment system.

Since air-stripping transfers contaminants to the

atmosphere, they must take into consideration allowable VOC emissions. In some parts of the State, such

as in the South Coast Air Quality Management District, emissions are strictly regulated and additional

treatment to reduce emissions to acceptable levels is

needed. GAC adsorption may be used with air-stripping to control emissions from a packed-tower aeration

system.

 The closed-loop air-stripping process is an innovative extension of the traditional air-stripping

technology. The closed-loop air-stripping process comAn evaporation pan with weather station in the background. bines air-stripping with an ultraviolet photo-oxidation

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This air stripping system at

McClellan Air Force Base in

Sacramento is being used

to clean groundwater

contaminated with solvents.

process to control VOC emissions. In this process, exhaust air is irradiated with UV radiation in a

photo-oxidation chamber, and VOCs are destroyed.

The end products are carbon dioxide, hydrochloric

acid, and ozone. The treated air is recycled to the PTA

unit.

Advanced Oxidation. In contrast to GAC or airstripping, advanced oxidation processes can destroy

organic contaminants rather than transferring them

from one medium to another. Examples of AOPs include treatment with UV, ozone/hydrogen peroxide,

and ozone/UV. AOPs provide more powerful oxidation and at faster rates than conventional oxidants such

as chlorine. As a result, they can remove compounds

which are not treatable with conventional oxidants.

These oxidants can also reduce disinfection by-products created by processes such as chlorination. To date,

much AOP work has focused on removing low-molecular weight solvents such as TCE and PCE from

contaminated groundwater, and on reduction of DBPs.

Membrane Technologies. Membrane technologies

include reverse osmosis, electrodialysis, microfiltration,

ultrafiltration, and nanofiltration. RO, MF, UF, and

NF are pressure-driven processes of barrier separation;

electrodialysis employs electrical potential as the driving force. Membrane processes have been used for

desalting, removal of dissolved organic materials, softening, liquid-solid separation, pathogen removal, and

heavy metals removal. Other promising membrane

technologies are membrane phase-contact processes.

These processes are not pressure driven but remove

contaminants by extraction into another phase, as do

air-stripping and solvent extraction.

RO membranes permit water to flow through

them while rejecting the passage of dissolved contaminants. This is based on the natural osmotic process

where water passes through a semipermeable membrane from a solution of higher concentration to a

lower one. In RO, a pressure greater than osmotic pressure is applied to the contaminated water. Water passes

through the membrane but contaminants are retained.

RO systems using newer membranes operate at about

250 psi for desalting brackish groundwater and up to

1,000 psi for seawater desalting.

Electrodialysis induces contaminant ions to migrate through a membrane, removing them from the

water. In an electrodialysis unit, contaminated water

is pumped into narrow compartments separated by alternating cation-exchange and anion-exchange

membranes, selectively permeable to positive and negative ions. A variation of this process is called

electrodialysis reversal. In electrodialysis, the electrical

current flow is always in the same direction. In EDR,

the electrical polarity is periodically reversed, which

reverses ion movement and flushes scale-forming ions

from the membrane surfaces.

MF, UF, and NF operate similarly to RO, but at

lower pressures. More stringent drinking water regulations coupled with diminishing sources of pristine

waters have stimulated interest in the use of membrane

technologies in drinking water treatment. The use of

low-pressure membrane filtration for municipal water

treatment is a relatively new concept in the water industry, which has traditionally used membranes for

removing salts or organic materials. MF operates at

pressures ranging from 20 to 100 psi and is capable of

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removing micron-sized (10-6 m ) materials. Colloidal

particles are physically rejected by MF membranes. UF

operates at pressures ranging from 3 to 150 psi and is

capable of removing materials that are on the order of

a nanometer in size (10-9 m) from water. Dissolved inorganic contaminants are not retained by MF and UF

membranes. One of the most novel applications of lowpressure membrane technology is the removal of

microorganisms such as coliform bacteria, viruses, giardia, and cryptosporidium from drinking water sources

without using chemicals for primary disinfection. The

efficiency of low-pressure membranes in removing

particles from untreated water supplies has been well

documented. MF and UF have shown to be capable

of consistently reducing turbidities to less than

0.1 NTU, regardless of the influent turbidity level.

NF operates at pressures ranging from 150 to

300 psi and has characteristics between those of RO

and MF. The capital cost of an NF plant is typically

high compared to conventional treatment plants because of the cost of membranes and high-pressure

equipment. Pilot and bench-scale studies have demonstrated that nanofiltration is effective in removing

DBP precursors and SOCs such as pesticides. NF is

also frequently used for water softening applications.

Ion-Exchange. The process passes contaminated

water through a packed bed of anion or cation resins.

The resin type is selected based on the contaminant to

be removed. The treatment process exchanges ions

between the resin bed and contaminated water. By displacing ions in the resin, contaminant ions become

part of the resin and are removed from process water.

During the ion-exchange process, the exchange capacity of the resin becomes depleted and needs

regeneration to become effective. Sodium chloride

brine is used to regenerate the resin. Ion-exchange is

widely used for removing nitrates in groundwater and

for removing some metals. It may also be used for water

softening. Its effectiveness in removing radionuclides

is being investigated in a number of full scale applications.

Chemical Precipitation. Chemical precipitation

is used for removing heavy metals from water. The contaminants are precipitated from solution and removed

by settling. There are several types of chemical addition systems including ones using carbonates,

hydroxides, and sulfides. The carbonate system uses

soda ash and pH adjustment. The hydroxide system is

most widely used for removing inorganics and metals.

The system uses lime or sodium hydroxide to adjust

the pH upward. The sulfide system removes most

inorganics (except arsenic). The disadvantage is that

sulfide sludges are susceptible to oxidation to sulfate

when exposed to air, resulting in resolubilization of

the contaminants.

Biological Treatment. Biological treatment uses

microorganisms to remove contaminants in water

through metabolic processes. The process can be a suspended growth system, where the microorganisms and

nutrients are introduced in an aeration basin as suspended material in a water-based solution, or a

fixed-film system where the microorganisms attach to

a medium which provides inert support. Biological

treatment is used in municipal wastewater treatment

and for treating water containing organic compounds

such as petroleum hydrocarbons. Biological treatment

is often used for remediation of leaking fuel tank sites,

either above ground, or in situ.

Disinfection. This treatment inactivates pathogens

in water. The most common disinfection process is

chlorination, often used to treat wastewater and drinking water. Two relatively new disinfection processes

applied in water recycling include UV radiation and

ozonation. UV has recently been approved by the DHS

for disinfecting recycled water. UV has been shown to

be as effective as chlorine or ozone in reducing coliform

bacteria and is more effective at virus removal. UV has

the potential to be more cost effective than chlorine

disinfection, and eliminates the DBPs and handling

hazards associated with chlorination.

Innovative Treatment Technologies. Many innovative technologies are being used to treat contaminated

groundwater at hazardous waste sites. These technologies typically combine basic processes with a few

special techniques. In the future, these technologies may see broader application in groundwater

recovery projects. Some examples of these technologies, primarily those applied at pilot or full scales, are

covered below.

The EnviroMetal Process, a proprietary technology, treats groundwater in situ using reactive metal

(usually iron) to enhance the abiotic degradation of

dissolved halogenated organic compounds. A permeable treatment wall of the coarse-grained reactive

metallic media is installed across a plume of contaminated groundwater, breaking down contaminants as

they migrate through the aquifer. This technology has

received regulatory approval for use in at least two industrial facilities in California for treating shallow

plumes with elevated levels of VOCs.

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Integrated vapor extraction and steam vacuum

stripping removes VOCs, including chlorinated hydrocarbons, in groundwater and soil. The integrated

system has a vacuum countercurrent stripping tower

that uses low-pressure steam to treat contaminated

groundwater, and a soil vapor extraction process to treat

the soil. The stripper and the soil vapor extraction systems share a GAC unit to decontaminate the combined

vapors. The technology has been used to treat TCEcontaminated groundwater and soil.

Steam-enhanced extraction uses injection wells to

force steam through the soil to enhance vapor and liquid extraction thermally. The process extracts volatile

and semivolatile organic compounds from contaminated soil and groundwater. The recovered

contaminants are condensed or trapped by activated

carbon filters. After treatment is complete, subsurface

conditions are suitable for biodegradation.

Subsurface volatilization and ventilation technology uses a network of injection and extraction wells to

treat subsurface organic contamination through soil

vapor extraction and in situ biodegradation. A vacuum

pump extracts vapors while an air compressor injects

air in the subsurface. In most sites, extraction wells are

placed above the water table and injection wells are

placed below the groundwater level. Because it provides oxygen to the subsurface, the process can enhance

in situ bioremediation.

The PACT wastewater treatment system is a proprietary technology that combines biological treatment

and PAC adsorption to contaminated water. Microorganisms and PAC contact wastewater in an aeration

tank. The biomass removes biodegradable organic

contaminants, and PAC enhances adsorption of organic compounds. PACT systems treating up to

53 mgd of wastewater are in operation. This process is

applicable to groundwater contamination from hazardous waste sites.

Capacitive deionization desalting is an experimental process being researched at Lawrence Livermore

National Laboratory. It involves passing water through

electrodes made of carbon aerogel and generating a

small voltage differential between alternating positive

and negative electrodes, thus drawing ions out of the

solution. The ions are removed by electrostatic attraction and are retained on the electrode until the polarity

is reversed. The ions are then captured with a small

amount of water. Other dissolved materials such as

trace metals and suspended colloids are removed by

electrodeposition and electrophoresis. The process has

been operating in a laboratory for over two years. Sodium chloride, sodium nitrate, and ammonium

perchlorate solutions have been tested with excellent

results. Electrode life has been acceptable in the laboratory, with electrodes operating for more than two

years with little degradation. The electrodes appear to

be regenerable with little loss of capability. Energy requirements appear less than current desalting

technologies. Field testing has begun in Northern California, and will later be moved to Southern California.

Application of Water Treatment Technologies

Water Recycling. Recycled water uses include

groundwater recharge, agricultural and landscape irrigation, wildlife habitat enhancement, industrial use,

and recreational impoundments. Groundwater recharge and agricultural and landscape irrigation

constitute the greatest uses of recycled water in the

State. Table 5-2 lists some water recycling plants having a capacity of at least 10 mgd.

Indirect potable reuse of recycled water has been

practiced for years through groundwater recharge programs. In Los Angeles County, the Montebello Forebay

Groundwater Recharge Project began recharging the

Central Basin aquifer with recycled water in 1962.

Currently up to 60 taf/yr of recycled water percolates

into the groundwater basin, from which it is later extracted for distribution in potable water systems. Water

Factory 21 in Orange County and the West Basin

Water Recycling Facility have been producing advanced

treated recycled water for seawater intrusion barrier

injection, with the majority of the injected water entering the groundwater and becoming part of the water

supply.

As advanced treatment technologies become more

cost-effective, and as public acceptance increases, augmentation of surface water supplies may become

another application for recycled water. The San Diego

water repurification program, discussed in the sidebar,

would be the first example of planned, indirect potable reuse where repurified water is discharged directly

into a surface reservoir without percolation or injection into groundwater. (Unplanned, indirect potable

reuse occurs whenever treated effluent is discharged

into a waterway upstream of another user’s water supply intake.) Reservoir retention allows for additional

monitoring of the repurified water prior to introduction to a potable water supply. Surface water supply

augmentation projects are approved by DHS on a caseby-case basis.

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TABLE 5-2

Water Recycling Plants with a Capacity of at Least 10 mgd

Name Capacity Treatment Process Type Of Reuse Annual Supply

(mgd)a (taf)

San Jose Creek Water

Reclamation Plant (Los

Angeles County

Sanitation District)

100 Primary sedimentation,

activated sludge,

coagulation, filtration and

chlorination

Groundwater recharge,

agricultural and landscape

irrigation, and nursery stock

irrigation

43.2

Donald C. Tillman Water

Reclamation Plant (City of

Los Angeles)

80 Primary sedimentation,

activated sludge,

coagulation, filtration,

chlorination, and

dechlorination

Recreational lake, wildlife lake,

and Japanese garden

20.0

Fresno-Clovis Metropolitan

Area Regional Wastewater

Facilities

60 Primary sedimentation,

trickling filter, and activated

sludge

Agricultural irrigation 13.7

Los Coyotes Water

Reclamation Plant (Los

Angeles County Sanitation

District)

37 Primary sedimentation,

activated sludge, coagulation,

filtration, and chlorination

Landscape irrigation,

industrial reuse (process water,

concrete mix, and dust

control), and crop irrigation

5.9

West Basin Water Recycling

Facility (West Basin Water

District)

37 Coagulation, filtration,

clarification and reverse

osmosis (5 mgd),

microfiltration and reverse

osmosis (2.5 mgd)

Industrial use, landscape

irrigation, and seawater

intrusion barrier

8.4

Chino Basin Municipal

Water District Regional

Plant No. 1

32 Activated sludge, coagulation,

filtration, chlorination, and

dechlorination

Landscape irrigation and

recreational lakes

1.7

Terminal Island Treatment

Plant (City of Los Angeles)

30 Primary sedimentation,

activated sludge, filtration,

reverse osmosis, and

microfiltration

Seawater intrusion barrier and

industrial use

0b

Salinas Valley Reclamation

Plant (Monterey Regional

Water Pollution Control

Agency)

30 Primary sedimentation,

trickling filters, coagulation,

filtration, and disinfection

Agricultural irrigation 13.2

Long Beach Water

Reclamation Plant

25 Primary sedimentation,

activated sludge, coagulation,

filtration, and disinfection

Landscape irrigation, nursery

irrigation, and repressurization

of oil-bearing strata

5.1

City of Modesto Wastewater

Quality Control Facility

25 Primary sedimentation,

trickling filter, oxidation

ponds, and chlorination

Fodder crop irrigation 14.4

City of San Diego North

City Water Reclamation

Plant

30 Primary sedimentation,

activated sludge, coagulation,

filtration, and chlorination

Landscape irrigation 3.0

Central Contra Costa

Sanitary District Water

Reclamation Plant

25 Primary sedimentation,

activated sludge, UV

disinfection, coagulation,

filtration, and chlorination

Landscape irrigation, and light

industrial

1.2

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TABLE 5-2

Water Recycling Plants with a Capacity of at Least 10 mgd (continued)

Name Capacity Treatment Process Type Of Reuse Annual Supply

(mgd)a (taf)

Laguna Treatment Plant

(City of Santa Rosa)

18 Primary sedimentation,

activated sludge, coagulation,

filtration and chlorination

Fodder irrigation 9.3

Fairfield-Suisun Subregional

Wastewater Treatment

Plant

17 Activated sludge, coagulation,

filtration, chlorination, and

dechlorination

Sod farming and duck

hunting marsh maintenance

2.4

Michelson Water

Reclamation Plant (Irvine

Ranch Water District)

17 Primary sedimentation,

activated sludge, coagulation,

filtration, and chlorination

Landscape irrigation, nursery

irrigation, and toilet flushing

8.2

Whittier Narrows Water

Reclamation Plant (Los

Angeles County Sanitation

District)

15 Primary sedimentation,

activated sludge, coagulation,

filtration, and chlorination

Groundwater recharge and

nursery stock watering

9.4

San Jose/Santa Clara Water

Pollution Control Plant

15 Activated sludge, filtration

and chlorination

Landscape irrigation and

industrial processes

7.5

Los Angeles-Glendale Water

Reclamation Plant (City of

Los Angeles)

20 Primary sedimentation,

activated sludge, coagulation,

filtration, chlorination, and

dechlorination

Landscape irrigation and

industrial reuse

3.3

City of Bakersfield

Wastewater Treatment Plant

No. 2

19 Primary sedimentation and

oxidation ponds

Crop irrigation 16.8

Pomona Water Reclamation

Plant (Los Angeles County

Sanitation District)

13 Primary sedimentation,

activated sludge, coagulation,

filtration, and chlorination

Agricultural irrigation

landscape irrigation, and

industrial process

12.5

City of Visalia Water

Conservation Plant

12 Primary sedimentation,

trickling filter, activated

sludge, and chlorination

Non-food crop irrigation 4.9

Valley Sanitary District

Wastewater Treatment

Facility (Riverside County)

12 Primary sedimentation,

trickling filter, activated

sludge, and oxidation ponds

Non-food crop irrigation 4.3

City of Bakersfield

Wastewater Treatment Plant

No. 3

12 Primary sedimentation,

trickling filter

Agricultural irrigation 11.6

Desert Water Agency

Wastewater Reclamation

Facility (Riverside County)

10 Coagulation, filtration, and

chlorination

Landscape irrigation 2.7

Water Factory 21 (Orange

County Water District)

10 Coagulation, sedimentation,

filtration, carbon adsorption

(5 mgd), reverse osmosis

(5 mgd), and disinfection

Groundwater injection for

intrusion barrier

2.6

Lancaster Water

Reclamation Plant

10 Primary sedimentation,

oxidation ponds, and

chlorination

Wildlife refuge and fodder

irrigation

9.7

a

 One mgd equals 1,120 af/yr

b Expected to operate by 2000 with annual supply of 19 taf

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The California Potable Reuse Committee was

formed in 1993 to study the viability and safety of

indirect potable reuse. The committee, commissioned

by DHS and the Department, developed six criteria

that must be met before indirect potable reuse is allowed for augmentation of surface water supplies.

(DHS has other proposed regulations and criteria for

indirect potable reuse through groundwater recharge

projects.) The criteria are:

(1) Application of the best available technology in

advanced wastewater treatment with the treatment

plant meeting operating criteria. Best available

technology must include a membrane component

with the functional equivalency of reverse

osmosis.

(2) Maintenance of appropriate reservoir retention

times based on reservoir dynamics.

(3) Maintenance of advanced wastewater treatment

plant reliability to consistently meet primary microbiological, chemical, and physical drinking

water standards.

(4) Compliance with applicable State criteria for

groundwater recharge for direct injection of recycled water.

(5) Maintenance of reservoir water quality. In addition to meeting drinking water standards, recycled

water used for reservoir augmentation shall be of

equal or better quality than that in the storage reservoir on a constituent-by-constituent basis.

(6) Provision for an effective source control program.

The source control program is to include pretreatment/pollution prevention measures that prohibit

the discharge of any substance which, whether

alone or in combination with other wastewater

constituents, causes or threatens malfunction or

interference with the wastewater treatment process, constitutes a hazard to human health or safety,

or affects the water quality of the potable storage

reservoir.

Treatment criteria for reuse of municipal wastewater are mandated in Title 22 of the California Code

of Regulations. These criteria specify the treatment

level for specific reuse applications. Treatment technologies used for water recycling depend on the reuse

application. For most nonpotable reuse applications

at least secondary treatment is required. To achieve

secondary treatment, conventional biological treatment

processes such as activated sludge process, trickling filters, or oxidation ponds are used, followed by

sedimentation and disinfection with chlorine.

Tertiary treatment, which is often standard for

recycled water, is achieved by adding a filtration step

after secondary treatment and before final disinfection.

Two major types of filtration technology are applied

in tertiary treatment plants: conventional and direct

filtration. Conventional filtration, as defined in Title

22, includes coagulation, sedimentation, and filtration

to condition the water. Conventional filtration technology requires that the filters be backwashed to

prevent turbidity breakthroughs. The Title 22 backSan Diego Water Repurification Program

The City of San Diego, in conjunction with the San Diego

County Water Authority, proposes to repurify 16 taf/yr of

wastewater for indirect potable purposes. Results of pilot

studies conducted by the agencies show that wastewater

can be repurified to a level suitable for human

consumption. The agencies would construct an 18 mgd

wastewater repurification facility using state-of-the-art

technology to treat recycled water from the City of San

Diego’s North City Water Reclamation Plant. The repurified

water would be transported over 20 miles to the 90 taf San

Vicente Reservoir, where it would be blended with imported

raw water supplies and stored for a period of time. The blended

water would eventually be conveyed via the existing El Monte

Pipeline to the city’s Alvarado Filtration Plant for

traditional treatment before being delivered to the city’s

drinking water system.

Repurified water is based on a concept of multiple barriers.

Recycled water from the North City Water Reclamation Plant,

treated to levels acceptable for landscape irrigation and for

other nonpotable purposes, would be treated further at the

proposed 18 mgd wastewater repurification facility. The

repurification process would include subjecting the recycled

water to four more treatment processes — low-pressure microfiltration, reverse osmosis, ion-exchange, and ozonation. These

treatment processes, while redundant in their functions,

ensure reliability of the overall repurification system and

produce an end product that would exceed current health

and safety standards.

Pilot studies show that the City of San Diego could turn

recycled water into an alternative drinking water source. The

city is preparing an environmental document and has begun

design of the project. The project is expected to begin

operation in late 2002.

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wash requirements result in an equipment-intensive

process. Direct filtration provides a cost-effective and

convenient tertiary technology when secondary effluent quality is high. The technology will likely be

incorporated in areas where effluent from residential

areas provides the process water. Newer water recycling facilities use direct filtration as part of the tertiary

treatment process. Direct filtration bypasses the sedimentation step. Continuously backwashed direct

filtration technology is available, minimizing equipment needs.

Achieving the maximum use of tertiary treated

water for landscape irrigation and other outdoor applications depends on the ability to store the treated

water supply when it is not needed. Landscape irrigation demands, for example, have a wide seasonal

variation in the State’s inland areas. (Landscape irrigation demands also vary diurnally, with most sites

demanding recycled water at night when supplies are

at their lowest levels.) Groundwater recharge is often a

cost-effective solution to meeting seasonal demand patterns, allowing the storage of relatively large quantities

of recycled water without the capital cost investment

associated with above-ground reservoirs.

Desalting. According to the International Desalting Association’s inventory of worldwide desalting

plants, the United States is second in usage of desalting in the world, with almost 1 maf/yr of installed

capacity. (Only Saudi Arabia has more installed capacity.) In 1985, the United States had less than 7 percent of the world’s capacity; by 1993, that figure had

risen to nearly 15 percent. Common feedwater sources

for desalting plants include brackish groundwater, municipal and industrial wastewater, and seawater. Costs

of desalting increase with increasing feedwater salinity. Table 5-3 lists some larger desalting plants in

California.

Reverse osmosis accounts for 89 percent of the

installed capacity of desalting plants in California, including all the significant plants supplying municipal

water supplies or recycling municipal wastewater. Reverse osmosis is likely to continue to dominate in

California, given recent improvements in membrane

performance. Reverse osmosis membranes have

changed greatly in the last 20 years. Membranes are

available to serve many purposes. This allows water

suppliers to select and operate membranes specifically

suited to the feedwater quality and the required product water quality. Membranes have developed into two

principal classes.

The first class is the traditional reverse osmosis

membrane which rejects all salt ions (as well as other

dissolved constituents) equally. This process, also

called hyperfiltration, is used on water requiring the

removal of all classes of dissolved constituents. The

second class of membrane processes is represented by

MF, UF, and NF. For example, nanofiltration membranes reject larger dissolved ions such as calcium and

TABLE 5-3

Sample Desalting Plants

Site Owner Capacity Comments

(mgd)a

Brackish Water Desalting

Arlington Santa Ana Watershed 6.0 Operational

Project Authority

Tustin City of Tustin 3.0 Operational

Oceanside City of Oceanside 2.0 Operational, being expanded

West Basin West Basin MWD 1.5 Operational

Wastewater Desalting

Water Factory 21 Orange County WD 5.0 Operational, being expanded

West Basin West Basin MWD 5.0 Operational, being expanded to 7.5 mgd

San Diego City of San Diego 1.0 Operational

Seawater Desalting

Santa Barbara City of Santa Barbara 6.7 Standby as drought reserve

Morro Bay City of Morro Bay 0.6 Standby as needed

Marina Marina Coast Water District 0.3 Operational

Santa Catalina Island Southern California Edison 0.1 Operational

a

 One mgd equals 1,120 af/yr

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The California Water Plan Update BULLETIN 160-98

sulfate, along with equally large dissolved feedwater

constituents. When used in a water softening role, they

will remove calcium, magnesium, and sulfate from

water, but allow sodium and chloride ions to pass

through. Nanofiltration membranes are often used for

water softening.

Advances in membrane technology have reduced

operating pressures, increased flow rates, and increased

salt rejection in typical reverse osmosis applications—

thereby reducing treatment costs. As operating pressures have decreased, so have energy costs. Energy

requirements have accounted for at least 50 percent or

more of the operating costs of a reverse osmosis plant.

New membrane materials have allowed more membrane area per module and higher productivity per

square foot. Increased productivity of membranes and

their longer life expectancy reduces the capital cost of

the plant, reducing the cost of water. Increasing salt

rejection provides better water quality. In the case of

groundwater desalting, the high purity product water

can be blended with raw water to meet the desired

overall product water quality.

Treatment of Contaminated Groundwater

The selection of technologies for treating groundwater contamination depends on site conditions and

the contaminants to be removed. Although there are a

variety of options, no one technology is necessarily

capable of responding to all conditions found at a

groundwater contamination site. In practice, treatment

technologies are sometimes used in combination to

remediate contamination. For example, groundwater

contaminated with nitrates and pesticides requires ionexchange technology to remove the nitrates and GAC

adsorption to remove the pesticides. Table 5-4 provides some examples of contaminated groundwater

treatment sites. Treatment unit capacities at the locations shown range from 0.3 mgd to 4.1 mgd.

Some local agencies have integrated groundwater

treatment plants into municipal distribution systems.

The West Basin Municipal Water District for example,

constructed a 1.5 mgd facility that uses reverse osmosis technology to remove elevated levels of dissolved

solids from contaminated groundwater. The plant supplies about 1.5 taf annually of recovered groundwater

to the district for municipal use and to Dominguez

Water Corporation for municipal and industrial uses.

The Glenwood nitrate water reclamation plant,

owned by Crescenta Valley County Water District, is

a 3.7 mgd ion-exchange treatment plant. Treated

groundwater from the plant is sold to Foothill Municipal Water District and MWDSC for municipal and

industrial uses. The plant’s eventual project yield will

be about 1.6 taf annually. The City of Pomona operates a 15 mgd ion-exchange treatment plant, treating

nitrate-contaminated groundwater from the Chino

Groundwater Basin. At full capacity, the treatment

plant supplies about two-thirds of the city’s municipal

water demand.

Some aquifers in California are contaminated beSeawater Desalting–

Marina Coast Water District

Marina Coast Water District is the primary water supplier

for the City of Marina. MCWD relies on the Salinas Valley

groundwater basin as its primary water supply source, as do

other Salinas Valley urban and agricultural water suppliers.

Overdraft of the Salinas Basin has caused seawater from

Monterey Bay to migrate into two of the three aquifers

underlying the coastal part of Salinas Valley. Seawater

intrusion has rendered some groundwater unfit for use.

MCWD has had to replace shallower wells with deeper wells

to meet demands for potable water. MCWD investigated ways

to diversify its water supply sources because of potential

groundwater extraction limitations, and chose desalting as

its preferred option.

MCWD completed construction of a reverse osmosis

seawater desalting plant in 1997. The plant produces

approximately 300,000 gpd of potable water (equivalent to

340 af/yr), and uses beach wells for seawater intake and

brine disposal. A shallow production well drilled into

beach deposits near MCWD’s water treatment plant

provides intake water for the desalting plant. Using a

beach well to supply seawater minimizes the need for

extensive pretreatment. Beach sands filter most of the

suspended material in the seawater. The reverse osmosis

system is a single stage system operated at 40 to 45 percent

recovery rates.

The project produces a reject brine flow of about 450,000

gpd. An injection well in a shallow sand aquifer is used to

dispose of the brine. Power requirements for the desalting

plant are estimated at 5,000 kWh of electricity per acre-foot

of water produced, or about 15 kWh for each 1,000 gallons

of desalted water. Total capital costs for the desalting plant

were about $2.5 million.

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The California Water Plan Update BULLETIN 160-98

cause of past hazardous waste disposal practices. A

number of these sites are undergoing remediation. Carbon adsorption, membrane filtration, air stripping,

advanced oxidation processes, biological treatment,

chemical precipitation, and innovative treatment technologies are examples of technologies used. For

example, Aerojet General Corporation’s manufacturing facility in Rancho Cordova operates a 6.5 mgd

groundwater treatment facility which removes VOCs

from the groundwater. The treatment facility has airstripping towers and GAC adsorption units. Treated

groundwater is reinjected into the aquifer through

wells, and is also recharged via surface impoundments.

Another example is Valley Wood Treating Company

in Turlock, which uses pump-and-treat and in situ treatment techniques for chromium-contaminated

groundwater. The company pumps groundwater and

uses chemical precipitation for first stage contaminant

removal. Next, a reducing agent is added to the treated

water, which is then reinjected into the aquifer. The

resulting reaction reduces chromium in situ and

subsequently fixes residual chromium in the soil.

Water Supply/Flood Control

Technologies

Inflatable Dams

Inflatable rubber, or fabric and rubber, dams and

tubes have been used for years as weirs to impound

water for water supply and flood control. Inflatable

dams were developed and first used in the 1950s in

the Los Angeles area. They were typically inflated

with water. Since that time, construction materials

and control systems have been improved and features have been added, such as fins to reduce

vibrations during overflow. Air is now the preferred

inflation medium. The manufacturers report that

there are about 1,900 of these dams worldwide, with

50 in the United States.

Alameda County Water District’s Rubber Dam

No. 3 is a representative example of a modern inflatable dam. The 13-foot-high, 375-foot-long dam was

TABLE 5-4

Examples of Contaminated Groundwater

Treatment Sites

Location Contaminant Treatment

Lodi DBCP GAC

Lodi Pathogens UV

Modesto DBCP GAC

Modesto Nitrates Electrodialysis

Fresno DBCP GAC

Fresno TCE Air-stripping

Clovis DBCP GAC

Monrovia TCE Air-stripping

Monrovia VOCs Air-stripping

San Gabriel Valley VOCs GAC

Remediation of Nitrate Contamination–

City of McFarland

The City of McFarland in Kern County has a population of

about 7,650 people. McFarland Mutual Water Company

supplies municipal water. The company depends on groundwater

for raw water supply and has four active wells.

Elevated levels of nitrates in MMWC’s water were detected

in the early 1960s. Many wells sampled showed nitrate levels

exceeding the drinking water standard. Studies identified

fertilizer application on agricultural lands as a major contributor

to nitrates in the groundwater. MMWC abandoned two of its

wells due to nitrate contamination and provided treatment for

two wells to reduce nitrate levels to meet drinking water

standards. Two deeper replacement wells were constructed to

extract groundwater unaffected by nitrate or pesticide

contamination.

In 1978, the MMWC received an EPA grant to study

groundwater treatment alternatives, leading to the 1983

construction of a 1 mgd ion-exchange treatment plant. A second

1 mgd ion-exchange treatment plant for another well was

constructed in 1983. The two wells supply about 20 af annually

of treated water to McFarland and adjoining rural areas within

the MMWC service area.

The plants’ designs rely heavily on technology and practices

used in the water softening industry. Plant location was dictated

by the existing wells and distribution systems. Because there

was no centralized distribution system, the plants had to be

designed to operate from a single well. Well pumps operate on

a demand basis, so the plants had to be able to operate

automatically. The system was designed to accept water directly

from the well, treat for nitrate removal, and allow treated water

to flow directly into the distribution system. The ability of the

process to adapt to quick start-up and frequent on-off operation

was an important consideration in choosing it over reverse

osmosis and biological treatment methods.

EE-RM-PET-100 C0MMENT 01A
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The California Water Plan Update BULLETIN 160-98

constructed in 1989 on Alameda Creek in the City of

Fremont. The dam impounds a 154 af reservoir for

direct groundwater recharge and diverts flows into

adjacent spreading grounds in former aggregate pits.

The air-inflated dam is bolted to a reinforced concrete

slab that was constructed across the stream channel.

To clear the leveed channel for flood flows, the dam is

deflated by district personnel, or it automatically deflates slowly when overtopped by substantial flows. The

dam is reinflated when stream flows subside to safe

levels and any water-borne debris has passed the dam.

These operations are much easier and safer than alternatives such as installing, tripping, and reinstalling

hinged flashboards. A similar inflatable dam has been

used in the Russian River at Mirabel since 1976, where

water is diverted to percolation ponds.

The San Gabriel, Los Angeles, and Santa Ana River

Basins also have similar devices. OCWD installed two

large air inflatable rubber dams across the Santa Ana

River (Imperial Highway Dam in 1992 and Five Coves

Remediation of Volatile Organics

Contamination–McClellan Air Force Base

In 1981, McClellan AFB initiated soil and groundwater

investigation as part of a Department of Defense program to

identify and evaluate suspected contamination at military

installations nationwide. Groundwater contaminants

identified included VOCs, SVOCs, petroleum hydrocarbons,

and trace heavy metals. Subsequent investigations revealed

that contaminants had migrated off the base. At least one

municipal well was abandoned because of contamination. In

1986 and 1987, 500 homes with private domestic wells to

the west of the base were connected to the City of Sacramento’s

water system.

In 1987, groundwater extraction and on-site treatment

began. The treatment involved an air stripper, with

incineration and caustic scrubbing of the air stream,

followed by carbon adsorption and biological treatment

of the effluent. The treatment plant had a capacity of 1.44

mgd and discharged its treated water to Magpie Creek and to

a wetland area under permits from the Central Valley

RWQCB. Later, the biological treatment unit was removed

when the concentration of ketones was low enough to be

removed by the air stripper and carbon adsorption units.

In 1996, the air stripper and incinerator were replaced with

a UV/ hydrogen peroxide system to remove volatile organics.

The GAC is still in use. Operating and maintaining the

new system is less expensive than the air-stripping and

incinerating process, and the higher treatment efficiency

reduces carbon use in the GAC units. Several more years

of extraction and treatment of the groundwater will be

required before the contaminated aquifer is restored to

usable quality.

Remediation of Pesticide and Fertilizer

Contamination–Occidental Chemical

Manufacturing Facility

In the late 1970s, pesticide and fertilizer contamination

was discovered in soil and groundwater at the Occidental

Chemical Agricultural Products manufacturing facility near

Lathrop. The primary contaminants found were

dibromochloropropane, ethylene dibromide, and sulfolane.

OxyChem removed or capped contaminated soil at the facility

in 1981 and 1982. The groundwater remediation program

began operation in 1982 and continues today. The original

groundwater restoration system was designed to remove

DBCP and EDB to 1 ppb. It consisted of five extraction wells,

a 500 gpm treatment system, and two wells for deep injection

of treated groundwater into an unusable confined aquifer.

Sulfolane was not removed from the groundwater, but its

injection to the aquifer was considered acceptable since the

aquifer was designated unusable for domestic or agricultural

purposes. SWRCB Resolution No. 88-63 in 1988, a 1989

revision of MCLs for DBCP and EDB, and a 1989 DHS

maximum allowable level for sulfolane in municipal water

resulted in more stringent treatment requirements. OxyChem

made operational changes in the treatment system and added

a biological treatment system in 1992 (microbial inoculation

of the carbon treatment system) to remove sulfolane from

the groundwater to comply with the new treatment standards

of 0.2 ppb DBCP, 0.02 ppb EDB, and 57 ppb sulfolane.

Two extraction wells were added, increasing treatment capacity

to 600 gpm.

The groundwater restoration system was designed to treat

the contaminated groundwater and to control the hydraulic

gradient in order to prevent off-site migration of the

contaminants. Several dozen monitoring wells were built to

monitor the effectiveness of the system. Monitoring reports

have shown reductions of contaminant concentrations and

control of contaminant plume. However, it is anticipated that

groundwater remediation will continue for many years.

EE-RM-PET-100 C0MMENT 01A
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The California Water Plan Update BULLETIN 160-98

This inflatable dam is

owned by Alameda

County Water District.

Dam in 1993) to divert flows into groundwater recharge basins. The dams are deflated when flows exceed

1,000 cfs.

Other uses of inflatable dams have evolved. In

1988, PG&E replaced flashboards on its Pit No. 3 dam

on the Pit River with 6-foot-high inflatable dams.

USBR recently replaced two 18-foot-high by 100-

foot-long drum gates on the crest of Friant Dam

with Obermeyer gates. The gates are steel panels

connected to the dam crest by hinges along their

upstream edge, and are raised and lowered by airinflated bladders. During the flood of January

1997, an inflatable rubberized berm was installed

on the water side of the Sutter Bypass levee to provide the additional height needed to protect the

levee from overtopping. Rubber berms of this type

are used as cofferdams during construction

projects in wet environments or as pollution containment devices.

Weather Modification

Since the early 1950s, California water users have

practiced cloud seeding to augment precipitation,

mostly along the western slopes of the Sierra Nevada

and along the Coast Range. In 1996, there were 14 active cloud seeding programs operating in California.

The goal of these programs is to increase water supply

for hydroelectric power generation and for agricultural

and municipal uses. Cloud seeding programs have potential legal and institutional issues associated with

them, including claims from third parties who allege

damages from flooding.

The principal elements of cloud seeding include

selection of cloud masses, seeding materials, and methods to dispense the agents within the clouds. Several

classes of seeding agents are available. Seeding agents

are introduced into the clouds by either ground-based

generators or aerial delivery systems.

Precipitation from clouds is a result of two different processes or mechanisms. The first is coalescence,

whereby tiny cloud droplets collide to form larger droplets that eventually fall as rain. The coalescence process

works at temperatures above freezing. The second

mechanism requires ice particles and occurs at subfreezing temperatures. Many clouds contain

supercooled water droplets, sometimes at temperatures

far below freezing. Eventually the ice particles fall as

snow (which will change to rain if the lower levels of

the atmosphere are above freezing). Enhancing either

of the two processes of precipitation formation can

lead to more efficiency in producing rain or snow from

a cloud. Some natural clouds appear to be deficient in

ice forming nuclei; those clouds offer an opportunity

to assist the rainmaking process.

Cloud Seeding Agents. Certain materials have

EE-RM-PET-100 C0MMENT 01A
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The California Water Plan Update BULLETIN 160-98

been found effective in converting supercooled water

droplets into ice crystals. Commonly used seeding

agents for this purpose are silver iodide and dry ice.

Some other chemicals also work, including some organic compounds. Hygroscopic materials such as salt,

urea, and ammonium nitrate have been used in warmer

clouds to assist the coalescence process.

Dry ice was frequently used in early cloud seeding

programs in the United States in the 1950s and early

1960s. A switch to silver iodide occurred in the mid1960s, probably because of more convenient storage

and dispensing capabilities (dry ice applications are limited to airborne delivery systems). Dry ice has received

increased attention in recent years due to its low cost

and high effectiveness.

Silver iodide has been the preferred seeding agent

in the majority of cloud seeding programs in the United

States. Particles of silver iodide are usually produced

through a combustion process followed by rapid

quenching which forms trillions of effective freezing

nuclei per gram of silver iodide consumed. Cloud seeding by silver iodide can be carried out using

ground-based or aerial generators.

Liquid propane is a freezing agent much like dry

ice. Liquid propane has the advantage of working at

higher temperatures, up to a degree or two below freezing, whereas silver iodide is not very effective when

temperatures are warmer than -50 C. Dispensing is limited to ground-based systems because it is a flammable

substance. Liquid propane sprayed into the atmosphere

chills the air to temperatures well below 00 C. As temperatures approach -40o

C, water vapor in the air rapidly

condenses into trillions of cloud droplets which immediately freeze and grow into tiny ice crystals. Propane

is used operationally in clearing supercooled fog from

airports in Alaska and the northern portion of the continental U.S.

Pseudomonas syringae, a bacterium thought to reduce frost damage in plants, has been shown to be an

effective nucleating agent. Use of this bacterium as a

seeding agent has been limited to producing snow in

ski resorts, although there have been some experiments

with aerial applications.

Cloud Seeding Delivery Systems. Commonly

available aircraft can be modified to carry an assortment of cloud seeding devices. Silver iodide nuclei

dispensers include pyrotechnic dispensers and models

that burn a solution of silver iodide and acetone. In

the burning process, a typical silver iodide-acetone solution is forced through the nozzle into a combustion

chamber where it is ignited, and the silver iodide crystals formed through combustion are expelled into the

atmosphere. Pyrotechnics are similar to ordinary highway flares. Pyrotechnic flares impregnated with silver

iodide can be mounted on aircraft, burned, and

dropped into the clouds. Dry ice is frequently dispensed

through openings through the floor of aircraft modified for cloud seeding. Types of aircraft used in

operational cloud seeding programs range from a single

engine aircraft to larger twin engine aircraft.

The most common type of ground generator consists of a solution tank which holds the seeding agent.

Other components include a means of pressurizing the

solution chamber, dispensing nozzles, and a combustion chamber. Frequently, such systems employ a

propane tank with a pressure reduction regulator

to pressurize the solution tank, as well as to provide

as a combustible material into which the silver iodideacetone solution is sprayed. Other systems utilize

nitrogen to pressurize the solution tank. Pyrotechnics

are also used at surface sites. Ground generation systems have been developed which are operated manually

or by remote control.

Effectiveness. Although precise evaluations of the

amount of water produced are difficult and expensive

to determine, estimates range from 2 to 15 percent

increase in annual precipitation, depending on the

number and type of storms seeded. In 1992, both the

American Meteorological Society and the World Meteorological Organization issued policy statements

cautiously supportive of the effectiveness of weather

modification efforts under the proper circumstances.

Long-Term Weather Forecasting

California’s experience with flood and drought

cycles demonstrates that significant economic benefits

would result from the development and application of

successful long-term weather forecasting capabilities.

With the ability to predict weather patterns in an accurate and timely manner, water resources managers

could plan for and mitigate losses associated with floods

and droughts.

During the 1980s, research on ocean and atmospheric interactions in the tropical Pacific Ocean

produced new and significant insights into the

predictability of the so-called El Niño Southern Oscillation cycle. New weather forecasting capabilities

developed through research on ENSO suggest potential applications in addressing water resources

management issues.

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Climate researchers at Scripps Institution of

Oceanography are engaged in several efforts to provide experimental climate forecasts up to twelve months

in advance. One of these efforts is focused on the use

of climate forecasts to improve California’s use of its

scarce water resources. Scripps is leading a team of

University of California scientists to downscale global

climate predictions to describe impacts on local water

supplies. See Chapter 3 for a discussion on climate

variability.

Environmental Water Use

Technologies

Wetlands Management

Wetland plants have been found to remove selenium from water applied to them. University of

California, Berkeley, researchers are experimenting in

the Tulare Lake Drainage District with wetland plants

irrigated with high-selenium drain water in flowthrough cells. Careful management of such facilities

to remove selenium while avoiding food chain concentrations may result in developing safe operating

criteria for wetlands supplied with agricultural drainage water. This may provide another alternative for

drainage water management. (Drainage water not used

to support wetlands would still have to be disposed of

by other means, such as evaporation ponds.)

Real-Time Water Quality Management

One of the actions identified in the 1995 SJRMP

plan was establishing a real-time water quality monitoring network for the San Joaquin River, to support

water management decisions. The monitoring network

collects water quality and quantity data for input to a

computer model that forecasts water flow and quality

along the lower San Joaquin River.

A goal of the real-time monitoring network is to

enable water managers to meet San Joaquin River water quality objectives more often and more efficiently.

For example, information provided by the network can

support decisions related to reservoir releases at New

Melones.

 A recently completed demonstration project

added instrumentation sites, developed analytical tools

to collect and process the data, and disseminated weekly

forecasts of daily San Joaquin River flow and salinity

at Vernalis. In 1997, CALFED approved Category III

funding to implement a two year program to expand

the monitoring network. The program is scheduled to

begin in fall 1998.

Fish Screen Technologies

State of the Art. Fish screens on water supply diversions protect fish from potential entrainment losses.

A properly designed fish screen, with appropriate

sweeping velocities past the screen, allows diversions

to occur (even when juvenile fish may be present) without causing unacceptable fish losses. Fishery and water

interests have been working together for several years

to improve existing screens and add them to older diversions that lack screens.

NMFS and DFG have mandates for the installation and operation of fish screens. If a new diversion is

installed or significant changes are made to an existing

intake, a new fish screen is usually required. DFG has

established a prioritized list of diversions that should

be screened based on potential fish losses. Protecting

the most significant diversions first will help achieve

fish protection goals with the available financial resources. Programs to financially assist diverters in the

installation of such screens are available through the

CVPIA’s AFRP, CALFED’s ecosystem restoration program, the Natural Resources Conservation Service, and

provisions of Proposition 204.

Current fish screen technology reflects criteria established by NMFS and DFG. Physical screens,

combined with low approach velocities and proper

cleaning systems, can effectively protect fish greater

than about 1 inch long. Conventional screens will not

protect smaller or larval-sized fish which may be present

at some sites for limited durations.

Smaller pumped diversions (slant or vertical pump

installations on a river with flows less than 40 cfs) generally use bolt-on screens available from a variety of

manufacturers. These screens are similar to those used

to reduce debris in sprinkler irrigation systems. Depending on the site and the system, screens may be

made of corrosion resistant woven wire, perforated

plate, or wedge-wire material (well screen). These materials can be formed into cylindrical shapes or flat

plate panels and designed into the intake system.

The number of sites with fish screens (or fish passage improvements) has increased with the availability

of public funding assistance (Figure 5-1). For example,

the Maxwell Irrigation District now operates a stateof-the-art positive barrier fish screen, one of the first

of its kind installed on the Sacramento River. Completed in 1994, the new pumping plant and screen

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In February 1998, two large

cylindrical fish screens were

installed at one of the

largest Delta diversions on

Sherman Island.

facility diverts approximately 80 cfs at a completed cost

of nearly $1.6 million. The screens are intended to

protect all fish, but primarily steelhead and winterrun chinook salmon. In 1994, Pelger Mutual Water

Company completed construction of its new pumping station and positive barrier fish screen near Knights

Landing on the Sacramento River. The facility includes

pumps with a discharge capacity of 60 cfs and was

completed for a total cost of $350,000.

Larger diversion sites are screened with low approach positive velocity barrier screens. These intake

screens may include significant civil works and are often off the main river channels where they must provide

fish handling and bypass systems. These facilities require more attention to hydraulic conditions than

smaller intake screens.

Several recently constructed facilities have been

designed to current regulatory criteria for screening,

including screens at the M&T Chico Ranch diversion

on the Sacramento River, the Parrott-Phelan diversion

on Butte Creek, and the Tehama-Colusa Canal. As part

of its environmental restoration activities, M&T Chico

Ranch relocated its screened pump station from the

mouth of Big Chico Creek to the Sacramento River.

This $5 million project provides water supply to over

8,000 acres of permanent wetlands and over 1,500 acres

of seasonal wetlands, in addition to protecting habitat

for migrating spring-run chinook salmon.

Several large facilities are nearing the final phases

of design or construction. They include diversions on

the Sacramento River at the Glenn-Colusa Irrigation

District, Reclamation District 108 near Grimes,

Reclamation District 1004 near Princeton, PrincetonCodora-Glenn Irrigation District and Provident

Irrigation District consolidated diversion, Browns Valley Irrigation District diversion on the Yuba River, and

others. Construction of GCID’s Hamilton City Pumping Plant screen began in spring 1998. This $70 million

project will minimize fish losses near the pumping plant

and will maximize GCID’s capability to

divert its full irrigation supply. Reclamation District

108 began construction in 1997 on a new $10 million

A newly constructed fish passage and screening facility on

Butte Creek.

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5

7

13

10

12

11

15

9

14

3

2

4

17

18 19

20

6

16

8 1

1

2

3

4

5

6

7

8

9

10

Sacramento River - M&T Chico Ranch, 1997

Butte Creek - Adams Dam, 1998

Butte Creek - Durham Mutual Dam, 1998

Butte Creek - Gorrill Dam, 1998

Butte Creek - Parrott - Phelan, 1996

Rock Slough - Contra Costa Canal, 1998

Sacramento River - Glenn-Colusa ID, 1998

Sacramento River - Maxwell ID, 1994

Sacramento River - Pelger MWC, 1994

Sacramento River - Princeton - Codora -

Glenn ID/Provident ID, 1998

11

12

13

14

15

16

17

18

19

20

Sacramento River - RD 108, 1998

Sacramento River - RD 1004, 1998

Sacramento River - Wilson Ranch, 1995

Suisun Marsh - Five Projects, 1996-1997

Yuba River - Browns Valley ID, 1998

Tehama - Colusa Canal, 1990

Butte Creek - Western Canal WD Dams, 1998

Butte Creek - Point Four Diversion Dam, 1993

Butte Creek - McGowan Dam, 1998

Butte Creek - McPherrin Dam, 1998

FIGURE 5-1

Recent Structural Fishery Improvements

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This circular flume, called the fish treadmill, simulates the

hydraulic conditions that fish may encounter in the Delta.

DWR’s three year treadmill study began in 1997.

fish screen. The project, located at the district’s Wilkins

Slough diversion, will protect migrating winter-run

chinook salmon and other fish. The district anticipates

completing the project by the 1999 irrigation season.

Reclamation District 1004 began construction of its

$8 million fish screen in 1998. The project includes

relocation of the Princeton Pumping Plant and conveyance facilities, in addition to a positive barrier fish

screen. In 1998, the Princeton-Codora-Glenn and

Provident irrigation districts are expected to complete

construction of an $11 million fish screen and pump

consolidation project. The 600 cfs project eliminates

three unscreened diversions.

Current Research. There is significant research

and experience in fish screen technology. The technology has responded to a number of factors including

ESA requirements in the Northwest and in California

for the protection of salmonids, FERC relicensing requirements, and the heightened awareness of fish losses

at diversions.

Research can be broken down into two categories: positive barrier technologies and behavioral barrier

technologies. Although physical screens are considered

state of the art, and are acceptable to the resource agencies, behavioral barriers have been demonstrated to

deter fish from being diverted at some sites and may

offer enhanced fish protection at even physically

screened sites.

Several significant applied research projects are

under way on positive barrier technologies. A research

pumping plant has been constructed at the USBR’s

Red Bluff Diversion Dam to divert Sacramento River

water into the Tehama-Colusa Canal. This facility (see

photo, Chapter 2) was developed to provide water to

the Tehama-Colusa Canal when the diversion dam

gates are raised for fish passage. The research pumping

plant is testing centrifugal and Archimedes screw pump

technologies to evaluate their impacts on fish. The research plant and the biological evaluations of its

effectiveness now being carried out are providing valuable data on the potential application of these

technologies to other sites.

Since the early 1950s, fish screen design criteria

have been developed for juvenile salmon and a few

other anadromous species. Little is known about the

screening requirements for resident Bay-Delta species

(such as smelt) which require protection. Through a

cooperative interagency program effort, a large circular screened testing flume has been constructed at

University of California at Davis to investigate fish

performance and behaviors under various hydraulic conditions. This research will improve

understanding of the needs of fish and help design

more effective screens.

Screen cleaning and proper operation and maintenance are essential for the reliability of diversion and

fish protection. In the last 10 years, cleaning technologies have advanced in response to possible zebra mussel

invasions and clogging from aquatic weeds. Combinations of hydraulic and air backwash systems,

improved horizontal and vertical brush cleaners, and

automated controls have proven effective. Screen materials and coatings have also been developed to prevent

biofouling. Some investigations under way include

USBR’s Tracy Pumping Plant Fish Facility Improvement Program, Contra Costa Water District’s new Los

Vaqueros and proposed Rock Slough fish screens, and

an investigation of air cleaning systems by USBR.

 Higher velocity fish screens, which reduce exposure to the screen surface, are being studied. These

systems are potentially less expensive because of the

reduced screen area required. Modular systems are being developed for wider application. Advances in

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The California Water Plan Update BULLETIN 160-98

automation and control systems are being used to regulate screens’ hydraulics and operations and provide

better fish protection and diversion reliability.

Technological advances have renewed interest in

acoustic and electrical fish guidance systems. In the

past, these systems have had limited success affecting

fish behavior. Some guidance and protection had been

observed, but the systems could not achieve the level

of protection desired by State and federal resource agencies. Fish responses to behavioral technologies are

variable since they may respond to other environmental stimuli, including hydraulic conditions,

temperature, predator avoidance, and lighting conditions. Behavioral barriers are attractive in some cases

because physical barriers may not be viable or costeffective.

Temperature Control Technology

Temperature control technology is used to manage temperature of reservoir releases to improve

conditions for downstream fisheries. During summer

months, reservoir temperature gradients result in

warmer water near the surface of a reservoir, with cooler

water remaining near the bottom. Two types of temperature control devices are currently being used in

Northern California reservoirs: variable-level outlets

Behavioral Barrier Demonstration Projects

Several behavioral barrier demonstration projects have been

evaluated in the Central Valley.

Georgiana Slough Acoustic Barrier

Juvenile salmon survival has been shown to improve

significantly if salmon are allowed to remain in the Sacramento

River rather than being drawn into the central Delta via

Georgiana Slough. Physical barriers and screens have been

considered at this site, but are not feasible because of hydraulic

conditions, water quality, recreational uses, and adult fish

migration issues. A behavioral system is being studied which

would improve fish survival by guiding them away from the

hydraulic influence of Georgiana Slough. Twenty-one

underwater acoustic speakers were installed at the Sacramento

River’s junction with the Slough below the town of Walnut

Grove. Studies in 1993, 1994, and 1996 showed improved

guidance during low flows, but mixed results at higher

flow conditions. Results have been encouraging enough to

continue investigations at this site under low flow conditions.

Adverse effects of acoustic system operation have not been

observed.

Reclamation District 108 Acoustic and Electrical Barrier

At this major Sacramento River diversion (700 cfs diversion

capacity) near Grimes, acoustic and electrical barriers were

tested to see if these technologies could reduce fish losses.

Tests were conducted at the site from 1993 until 1996 with

mixed results. The acoustic system was suspended from the

surface and operated on an on/off cycle to test its effectiveness.

The electrical array was mounted to an underwater louver

array and was similarly evaluated. Since neither system

achieved the required reduction in fish entrainment, RD 108

is constructing a positive barrier fish screen.

Reclamation District 1004 Acoustic Barrier

A similar acoustic barrier was installed at RD 1004’s

diversion on the Sacramento River near the town of Princeton.

From 1994 to 1995, the system was evaluated and found to

have marginal benefits. RD 1004 is installing a 360 cfs positive

barrier fish screen at its diversion site.

Behavioral Research at Other Sites

 The use of low frequency “infrasound” systems and the

use of lighting systems (strobe lights) is under investigation

at several sites outside of California. Many of these systems

are being tested and used with other screening technologies

to attempt to improve their effectiveness in difficult hydraulic

environments.

that permit temperature selective releases, such as

USBR’s Shasta Dam TCD; and temperature control

curtains, such as those at Whiskeytown and Lewiston

Reservoirs.

Temperature Control Devices. Some dams, such

as the Department’s Oroville Dam, were constructed

with temperature-selective reservoir release capability.

Retrofits to reservoir outlets can be constructed for

those that were not, such as USBR’s Shasta Dam.

USBR completed the Shasta Dam TCD in May 1997,

and is now fixing leakage problems that affect operation of the device. The structural steel shutter device is

250 feet wide by 300 feet high and encloses all five

penstock intakes on the dam. The shutters allow for

selective withdrawal of water, depending on downstream temperature needs. Prior to installation of the

structure, USBR had to bypass Shasta powerplant to

provide water of adequate temperature. Installation of

the TCD will provide USBR with the flexibility to

provide optimal water temperature downstream for the

salmon fishery, and allow for hydropower generation.

Temperature Control Curtains. Curtains can

control water withdrawal at intake or outlet structures

to provide desired temperatures for salmonids and other

aquatic species, allowing water to be conserved for other

uses. Four temperature control curtains have been inEE-RM-PET-100 C0MMENT 01A
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The California Water Plan Update BULLETIN 160-98

stalled by USBR, two in Lewiston Reservoir (in 1992),

and two in Whiskeytown Reservoir (in 1993). These

curtains are constructed of Hypalon, a rubberized nylon fabric. They are supported in the water column by

steel tank floats and anchored to stay in place.

At Lewiston Reservoir, an 830-foot-long, 35-foot

deep curtain is suspended from flotation tanks and

secured by a cable and anchor system. This curtain

was designed to block warm surface water from the

Clear Creek Tunnel intake. As a result, cold water

from the bottom of the reservoir is diverted to

Whiskeytown Reservoir. A second curtain was installed

around the Lewiston Fish Hatchery intake structure

to allow warmer or colder water, depending on the

season, to be taken into the hatchery. The curtain,

300 feet long by 45 feet deep, was designed to either skim warmer water or underdraw cooler water,

depending on whether the curtain was in a sunken

or floating position.

Ideally, cold water diverted from Lewiston should

be routed through Whiskeytown’s hypolimnion (deep,

cold water layer) into the Spring Creek Conduit intake. To accomplish this, two curtains were installed: a

tailrace curtain downstream at Carr Powerplant, and

an intake curtain surrounding the Spring Creek Conduit intake. The tailrace curtain (600 feet long and

40 feet deep) was installed to force cold water from

Carr Powerplant into Whiskeytown’s hypolimnion

with a limited amount of mixing with the epilimnion

(warm surface water). This curtain restrains warm surface water from moving upstream toward Carr

Powerplant. With the tailrace curtain in place, mixing

is reduced where the density current plunges into the

hypolimnion upstream of the tailrace curtain. The second curtain (a 2,400-foot long, 100-foot deep,

surface-suspended curtain) surrounds the Spring Creek

Conduit intake. This curtain, like the Lewiston curtain, was designed to retain warm surface water while

allowing only cold water withdrawal.

The temperature curtains at Lewiston and

Whiskeytown Reservoirs reduce the temperature of

Trinity River diversions to the Sacramento River by as

much as 50

 F. According to USBR, this decrease is significant, making the temperature curtains a successful

tool for conserving reservoir releases.

The smaller temperature control curtains generally cost about $1,000 per foot. The large curtain at

Whiskeytown Reservoir cost about $1.8 million. The

expected duration of use is about 10 years before replacement may be required. To date, none of the four

curtains in place at these two reservoirs has needed

major repairs.

A number of studies are ongoing to better refine

the curtains’ use for temperature control, and to ensure that no adverse impacts result to biological

resources in the reservoirs where they are installed.

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The California Water Plan Update BULLETIN 160-98

DEPARTMENT OF WATER RESOURCES

STATE OF CALIFORNIA

CALIFORNIA

WATER PLAN UPDATE

BULLETIN 160-98

Volume 2

November 1998

Pete Wilson

Governor

Douglas P. Wheeler

Secretary for Resources

The Resources Agency

David N. Kennedy

Director

Department of Water Resources

EE-RM-PET-100 C0MMENT 01A
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The California Water Plan Update BULLETIN 160-98

Department of Water Resources, Sacramento, 1998

Copies of Bulletin 160-98 may be purchased for $25 from:

California Department of Water Resources

P. O. Box 942836

Sacramento, CA 94236-0001

Make checks payable to: Department of Water Resources

California residents add current sales tax

C

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The California Water Plan Update BULLETIN 160-98

Chapter 6. Evaluating Options From a Statewide Perspective

Statewide Water Budget .............................................................................................................................. 6-2

The Bulletin 160-98 Planning Process ........................................................................................................ 6-2

Major Steps in Planning Process ........................................................................................................... 6-4

Shortage Management .......................................................................................................................... 6-6

Using Applied Water Budgets to Calculate New Water Needs .............................................................. 6-6

Demand Reduction Options ....................................................................................................................... 6-8

Urban Water Conservation Options ..................................................................................................... 6-9

Outdoor Water Use ....................................................................................................................... 6-9

Residential Indoor Water Use ...................................................................................................... 6-10

Interior CII Water Use ................................................................................................................. 6-10

Distribution System Losses .......................................................................................................... 6-11

Agricultural Water Conservation Options .......................................................................................... 6-11

Irrigation Management (Options 1, 2, and 3) .............................................................................. 6-12

Water Delivery Flexibility (Option 4) .......................................................................................... 6-13

Canal Lining and Piping (Option 5) ............................................................................................ 6-13

Tailwater and Spill Recovery Systems (Option 6) ......................................................................... 6-13

Environmental Water Conservation Options ...................................................................................... 6-13

Water Supply Augmentation Options ....................................................................................................... 6-14

Conveyance Facilities ......................................................................................................................... 6-14

SWP Interim South Delta Program ............................................................................................. 6-14

CALFED Delta Conveyance ........................................................................................................ 6-14

Mid-Valley Canal ......................................................................................................................... 6-16

Surface Storage Facilities ..................................................................................................................... 6-16

Area of Origin Protections ........................................................................................................... 6-16

CALFED Surface Storage ............................................................................................................ 6-16

Multipurpose Storage Facilities .................................................................................................... 6-20

Groundwater and Conjunctive Use .................................................................................................... 6-22

Potential for Conjunctive Use in the Central Valley ..................................................................... 6-22

Recent Groundwater Studies with Statewide Scope ...................................................................... 6-23

 Water Marketing ............................................................................................................................... 6-25

Sources of Water for Marketing ................................................................................................... 6-26

Prospects for Water Marketing ..................................................................................................... 6-27

Drought Year Marketing .............................................................................................................. 6-29

Every Year Marketing ................................................................................................................... 6-31

Water Recycling and Desalting ........................................................................................................... 6-32

Water Recycling ........................................................................................................................... 6-32

Contents . . .

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The California Water Plan Update BULLETIN 160-98

Desalting ..................................................................................................................................... 6-33

Weather Modification ........................................................................................................................ 6-35

Other Supply Augmentation Options................................................................................................. 6-36

Importing Water from Out of State ............................................................................................. 6-36

Gray Water .................................................................................................................................. 6-36

Watershed Management on National Forest Lands ...................................................................... 6-36

Long-Range Weather Forecasting ................................................................................................. 6-37

Summary of Statewide Supply Augmentation Options ....................................................................... 6-37

CALFED ..................................................................................................................................... 6-37

Other Statewide Options ............................................................................................................. 6-38

Allocating Options Yield Among Hydrologic Regions ................................................................. 6-38

Uncertainties in the Bulletin Planning Process ............................................................................. 6-38

Options for Future Environmental Habitat Enhancement ........................................................................ 6-41

Central Valley Project Improvement Act ............................................................................................. 6-41

Category III Program ......................................................................................................................... 6-45

CALFED Bay-Delta Ecosystem Restoration Program ......................................................................... 6-46

Other Environmental Enhancement Options ..................................................................................... 6-47

SWP’s Sherman and Twitchell Islands Wildlife Management Plans .............................................. 6-47

Fish Protection Agreements.......................................................................................................... 6-47

Upper Sacramento River Fisheries and Riparian Habitat Restoration Program ............................. 6-47

Financing Local Water Management Options ........................................................................................... 6-47

Sources of Revenues ........................................................................................................................... 6-48

Financing Methods............................................................................................................................. 6-48

Self-Financing .............................................................................................................................. 6-49

Short-Term Debt Financing ......................................................................................................... 6-49

Conventional Long-Term Debt Financing ................................................................................... 6-49

Innovative Long-Term Debt Financing ........................................................................................ 6-49

Credit Substitution and Enhancement ......................................................................................... 6-50

State and Federal Financial Assistance Programs........................................................................... 6-51

Relationship Between Financing and Water Agency Ownership and Size ........................................... 6-51

Public Water Agencies .................................................................................................................. 6-51

Investor-Owned Water Utilities ................................................................................................... 6-51

Mutual Water Companies ............................................................................................................ 6-52

Appendix 6A. Regional Water Budgets with Existing Facilities and Programs............................................6A-1

Appendix 6B. Applied Water Shortages by Hydrologic Region with Existing Facilities and Programs ....... 6B-1

Appendix 6C. Estimating a Water Management Option’s Unit Cost ........................................................ 6C-1

Appendix 6D. Calculation of Minimum New Water Needs ..................................................................... 6D-1

Appendix 6E. Net Water Budgets ............................................................................................................. 6E-1

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The California Water Plan Update BULLETIN 160-98

Appendix 6F. Land Retirement Analysis in Drainage-Impaired Areas ........................................................ 6F-1

Appendix 6G. Review and Evaluation of Statewide-Level Storage Facilities That Could Be Included in

CALFED Alternatives .............................................................................................................................. 6G-1

Chapter 7. Options for Meeting Future Water Needs in

Coastal Regions of California

North Coast Hydrologic Region ................................................................................................................. 7-3

Description of the Area ........................................................................................................................ 7-3

Water Demands and Supplies ............................................................................................................... 7-3

Local Water Resources Management Issues ........................................................................................... 7-5

Klamath River Fishery Issues.......................................................................................................... 7-5

Trinity River Fish and Wildlife Management Program ................................................................... 7-5

Water Supplies of Small Coastal Communities .............................................................................. 7-6

Russian River Environmental Restoration Actions ......................................................................... 7-7

City of Santa Rosa Long-Term Wastewater Project ........................................................................ 7-8

SCWA Water Supply and Transmission Project .............................................................................. 7-8

Potter Valley Project ....................................................................................................................... 7-8

Water Management Options for the North Coast Region .................................................................... 7-8

Water Conservation ....................................................................................................................... 7-8

Modifying Existing Reservoirs or Operations ............................................................................... 7-10

New Reservoirs and Conveyance Facilities ................................................................................... 7-10

Groundwater Development or Conjunctive Use .......................................................................... 7-11

Water Recycling ........................................................................................................................... 7-11

Desalting ..................................................................................................................................... 7-11

Other Local Options.................................................................................................................... 7-11

Options Likely to be Implemented in North Coast Region ................................................................ 7-11

San Francisco Bay Hydrologic Region ....................................................................................................... 7-15

Description of the Area ...................................................................................................................... 7-15

Water Demands and Supplies ............................................................................................................. 7-15

North Bay .................................................................................................................................... 7-15

South Bay .................................................................................................................................... 7-17

Local Water Resources Management Issues ......................................................................................... 7-20

Bay-Delta Estuary ........................................................................................................................ 7-20

Suisun Marsh ............................................................................................................................... 7-20

Local Water Agency Issues ........................................................................................................... 7-20

Bay Area Regional Water Recycling Program ............................................................................... 7-24

Water Management Options for the San Francisco Bay Region .......................................................... 7-24

Conservation ............................................................................................................................... 7-24

Modify Existing Reservoirs/Operations ........................................................................................ 7-24

New Reservoirs and Conveyance Facilities ................................................................................... 7-27

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Groundwater Development or Conjunctive Use .......................................................................... 7-28

Water Marketing .......................................................................................................................... 7-28

Water Recycling ........................................................................................................................... 7-28

Desalting ..................................................................................................................................... 7-29

Other Local Options.................................................................................................................... 7-29

Statewide Options ....................................................................................................................... 7-29

Options Likely to be Implemented in San Francisco Bay Region ........................................................ 7-29

Central Coast Hydrologic Region ............................................................................................................. 7-33

Description of the Area ...................................................................................................................... 7-33

Water Demands and Supplies ............................................................................................................. 7-34

Northern PSA .............................................................................................................................. 7-34

Southern PSA .............................................................................................................................. 7-34

Local Water Resources Management Issues ......................................................................................... 7-35

Seawater Intrusion ....................................................................................................................... 7-35

Local Water Agency Issues ........................................................................................................... 7-36

Seawater Desalting ....................................................................................................................... 7-37

Water Management Options for the Central Coast Region ................................................................ 7-37

Water Conservation ..................................................................................................................... 7-40

Modify Existing Reservoirs or Operations .................................................................................... 7-40

New Reservoirs and Conveyance Facilities ................................................................................... 7-40

Groundwater Development and Conjunctive Use ........................................................................ 7-41

Water Marketing .......................................................................................................................... 7-41

Water Recycling ........................................................................................................................... 7-42

Desalting ..................................................................................................................................... 7-42

Other Local Options.................................................................................................................... 7-42

Statewide Options ....................................................................................................................... 7-42

Options Likely to be Implemented in Central Coast Region .............................................................. 7-42

South Coast Hydrologic Region ................................................................................................................ 7-47

Description of the Area ...................................................................................................................... 7-47

Water Demands and Supplies ............................................................................................................. 7-47

Los Angeles Aqueduct .................................................................................................................. 7-48

Colorado River Aqueduct ............................................................................................................ 7-48

State Water Project....................................................................................................................... 7-49

Local Surface Water Supplies ....................................................................................................... 7-50

Groundwater Supplies ................................................................................................................. 7-52

Local Water Resources Management Issues ......................................................................................... 7-54

Water Supply Reliability .............................................................................................................. 7-54

Management of California’s Colorado River Water ...................................................................... 7-56

Mono Basin ................................................................................................................................. 7-57

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Restoration of Coastal Wetlands and Estuaries ............................................................................. 7-57

Flood Control .............................................................................................................................. 7-58

Salinity Management Actions ...................................................................................................... 7-59

Groundwater Issues...................................................................................................................... 7-60

Southern California Comprehensive Water Reclamation and Reuse Study ................................... 7-61

Water Marketing .......................................................................................................................... 7-61

New Conveyance Facilities from Colorado River Region to South Coast Region ......................... 7-62

Mexican Border Environmental Quality Issues ............................................................................ 7-62

Water Management Options for South Coast Region ......................................................................... 7-62

Water Conservation ..................................................................................................................... 7-63

Modify Existing Reservoirs or Operations .................................................................................... 7-63

New Reservoirs ............................................................................................................................ 7-63

Groundwater Development and Conjunctive Use ........................................................................ 7-67

Water Marketing .......................................................................................................................... 7-67

Implementing the CRB’s Draft 4.4 Plan ...................................................................................... 7-68

Water Recycling ........................................................................................................................... 7-68

Desalting ..................................................................................................................................... 7-70

Other Local Options.................................................................................................................... 7-71

Statewide Options ....................................................................................................................... 7-71

Options Likely to be Implemented in South Coast Region ................................................................. 7-71

Appendix 7A. Options Evaluations for Coastal Regions ............................................................................7A-1

Chapter 8. Options for Meeting Future Water Needs

in Interior Regions of California

Sacramento River Hydrologic Region ......................................................................................................... 8-3

Description of the Area ........................................................................................................................ 8-3

Water Demands and Supplies ............................................................................................................... 8-3

CVP Water Supply ........................................................................................................................ 8-4

Supply from Other Federal Water Projects ..................................................................................... 8-5

SWP Water Supply ........................................................................................................................ 8-5

Local Surface Water Supply............................................................................................................ 8-5

Groundwater Supply...................................................................................................................... 8-6

Local Water Resources Management Issues ........................................................................................... 8-6

Sierra Nevada Foothills Water Supply ............................................................................................ 8-6

Foothill Area Water Supply from American River Basin ................................................................. 8-7

Sacramento Area Water Forum ...................................................................................................... 8-8

Colusa Basin Drainage District ...................................................................................................... 8-9

Groundwater Management Actions ............................................................................................... 8-9

American River Flood Protection ................................................................................................. 8-10

Yuba River Flood Protection ........................................................................................................ 8-11

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Sacramento River Mainstem Flood Protection and Water Supply................................................. 8-12

Putah Creek Adjudication ............................................................................................................ 8-12

Fish Passage at Red Bluff Diversion Dam ..................................................................................... 8-12

Glenn-Colusa Irrigation District Fish Screen ............................................................................... 8-13

Fish and Wildlife Restoration Activities in the Sacramento Valley ................................................ 8-13

Water Needs for Rice Field Flooding............................................................................................ 8-15

Water Management Options for the Sacramento River Region ........................................................... 8-15

Water Conservation ..................................................................................................................... 8-15

Modify Existing Reservoirs/Operations ........................................................................................ 8-15

New Reservoirs ............................................................................................................................ 8-17

New Conveyance Facilities ........................................................................................................... 8-19

Groundwater Development or Conjunctive Use .......................................................................... 8-19

Water Marketing .......................................................................................................................... 8-19

Water Recycling ........................................................................................................................... 8-19

Other Local Options.................................................................................................................... 8-19

Statewide Options ....................................................................................................................... 8-20

Options Likely to be Implemented in the Sacramento River Region................................................... 8-20

San Joaquin River Hydrologic Region ....................................................................................................... 8-23

Description of the Area ...................................................................................................................... 8-23

Water Demands and Supplies ............................................................................................................. 8-24

Surface Water............................................................................................................................... 8-24

Groundwater ............................................................................................................................... 8-26

Local Water Resources Management Issues ......................................................................................... 8-27

Cosumnes River Flood Management ........................................................................................... 8-27

Integrity of Delta Levees .............................................................................................................. 8-27

Interim South Delta Program and Temporary Barriers Project ..................................................... 8-28

San Joaquin County Groundwater Overdraft ............................................................................... 8-29

 Penn Mine Remediation ............................................................................................................. 8-29

Conservation Storage in Farmington Reservoir ............................................................................ 8-29

New Melones Reservoir Water Supply and Operations ................................................................ 8-30

Urban Growth Pressures from San Francisco Bay Area ................................................................. 8-30

East County Water Supply Study ................................................................................................. 8-31

Los Banos Grandes Reservoir Studies ........................................................................................... 8-31

Merced Area Conjunctive Use Study............................................................................................ 8-32

Agricultural Drainage .................................................................................................................. 8-32

Enlargement of Friant Dam ......................................................................................................... 8-33

Instream Flow Requirements Below Friant Dam .......................................................................... 8-33

Environmental Restoration Activities in the San Joaquin River Basin ........................................... 8-33

San Joaquin River Parkway Development .................................................................................... 8-34

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January 1997 San Joaquin River Region Flood Event ................................................................... 8-34

Water Management Options for the San Joaquin River Region .......................................................... 8-35

Water Conservation ..................................................................................................................... 8-35

Modify Existing Reservoirs .......................................................................................................... 8-35

New Reservoirs ............................................................................................................................ 8-35

New Conveyance Facilities ........................................................................................................... 8-37

Groundwater Development or Conjunctive Use .......................................................................... 8-38

Water Recycling ........................................................................................................................... 8-38

Desalting ..................................................................................................................................... 8-38

Statewide Options ....................................................................................................................... 8-38

Options Likely to be Implemented in the San Joaquin River Region .................................................. 8-38

Tulare Lake Hydrologic Region ................................................................................................................. 8-43

Description of the Area ...................................................................................................................... 8-43

Water Demands and Supplies ............................................................................................................. 8-44

Local Water Resources Management Issues ......................................................................................... 8-45

Groundwater Overdraft ............................................................................................................... 8-45

Groundwater Banking Programs .................................................................................................. 8-46

Agricultural Drainage .................................................................................................................. 8-46

Arroyo Pasajero and Other Westside Cross-Drainages .................................................................. 8-47

Kings River Fishery Restoration Actions ...................................................................................... 8-47

Water Management Options for the Tulare Lake Region .................................................................... 8-47

Water Conservation ..................................................................................................................... 8-47

Modifying Existing Reservoirs and New Reservoirs ...................................................................... 8-49

New Conveyance Facilities ........................................................................................................... 8-50

Groundwater Development or Conjunctive Use .......................................................................... 8-50

Water Marketing .......................................................................................................................... 8-51

Water Recycling and Desalting .................................................................................................... 8-52

Statewide Options ....................................................................................................................... 8-52

Options Likely to be Implemented in the Tulare Lake Region ............................................................ 8-52

Appendix 8A. Options Evaluations for Interior Regions............................................................................8A-1

Chapter 9. Options for Meeting Future Water Needs in Eastern Sierra and Colorado

River Regions of California

North Lahontan Hydrologic Region ........................................................................................................... 9-3

Description of the Area ........................................................................................................................ 9-3

Water Demands and Supplies ............................................................................................................... 9-3

Local Water Resources Management Issues ........................................................................................... 9-7

Truckee River Operating Agreement .............................................................................................. 9-7

Walker River .................................................................................................................................. 9-8

Lake Tahoe .................................................................................................................................... 9-8

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