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served by surface water. Future water demands in the

Truckee Basin are not expected to exceed the

interstate allocations contained in the Truckee-CarsonPyramid Lake Water Rights Settlement Act (PL

101-618), which limits the basin’s annual use to 32 taf.

On the California side of the Lake Tahoe Basin,

South Tahoe PUD, Tahoe City PUD, and North Tahoe

PUD account for most of the water delivered to urban

users. Water is supplied from the lake and from groundwater sources. The interstate allocation for California’s

Lake Tahoe Basin in PL 101-618 would limit future

water use in the basin to 23 taf of gross diversions,

which represents the basin’s estimated future water

needs at its full development. Future development in

the Lake Tahoe Basin is strictly limited by the bistate

Tahoe Regional Planning Agency to protect the basin’s

environmental quality. In both the Truckee and Tahoe

Basins, water use for snowmaking at the area’s ski resorts has been addressed in the interstate allocations.

Urban development in the Carson and Walker

River Basins is minimal and is clustered around the

towns of Markleeville in Alpine County and Bridgeport in Mono County. More than 90 percent of the

watershed on the California side is federally owned,

primarily under the management of the Toiyabe National Forest. Groundwater is the source of supply for

individual users and small community systems located

in valley areas. In the upper watershed, communities

may lack suitable sites to locate wells and therefore

must depend on surface water sources. The Town of

Markleeville depends on surface water and experienced

a water shortage in 1989 when the stream that supplies the community went dry. Water had to be piped

4 miles from another creek to the town’s treatment

plant.

In the upper Carson River watershed, water is

stored in several very small alpine reservoirs originally

constructed to supply irrigation needs. Much of this

water is still used for irrigation downstream in Nevada. The largest of the alpine reservoirs is Heenan

Lake on Monitor Creek, tributary to the East Fork

Carson River, with a capacity of nearly 3 taf. The

Carson River supports a popular recreational trout fishery in the upper watershed. DFG has used Heenan

Lake for raising Lahontan cutthroat trout to stock at

other locations throughout the Sierra. DFG currently

manages State-owned lands adjacent to Heenan Lake

and has arranged to purchase water on an annual basis

to maintain a minimum reservoir pool for fish rearing.

Two special-purpose reservoirs were constructed

in the upper Carson watershed to receive treated wastewater effluent exported from South Tahoe PUD in the

Lake Tahoe Basin. (Disposal of treated wastewater

within the Lake Tahoe Basin was banned to help protect the lake’s clarity.) Beginning in the 1960s,

wastewater effluent was delivered to Indian Creek Reservoir for subsequent release to agricultural users as a

supplemental irrigation supply. In 1989, exports (about

5 taf/yr) were redirected to Harvey Place Reservoir.

Indian Creek Reservoir is now used for freshwater recreation.

In addition to several small reservoirs in the upper

watershed, the Walker River watershed has two large

reservoirs—Topaz Reservoir (an offstream storage facility on the West Walker) and Bridgeport Reservoir

on the East Walker. Both of the large reservoirs were

USBR’s Stampede Reservoir

is the second largest reservoir

in the Truckee River Basin.

Lake Tahoe is the largest

reservoir in the basin.

Courtesy of USBR

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built by Walker River Irrigation District to sustain summer irrigation flows in its service area downstream in

Nevada. WRID holds California water rights to store

57.6 taf of West Walker water, plus 200 af of local

inflow, in Topaz Reservoir. WRID can store up to 39.7

taf in Bridgeport Reservoir. SWRCB has established

instream flow and minimum reservoir pool requirements at Bridgeport, in response to fish kills that

occurred during the last drought. Both reservoirs are

popular local recreational destinations.

Part of the East Fork Carson River—approximately

10 miles from the town of Markleeville to the California/Nevada state line—has been added to the

California wild and scenic river system. On the West

Walker River, approximately 37 river miles have also

been given State designation. The designated reach is

from Tower Lake at the headwaters downstream to the

confluence with Rock Creek, and about 1 mile of

Leavitt Creek.

As occurred in the Truckee River Basin, water right

disputes in the Carson and Walker River Basins were

settled with federal court decrees. The 1980 Alpine

Decree on the Carson River and the 1936 Decree C125 on the Walker River control most river operations.

The decrees established surface water rights, including reservoir storage rights, of water users in both

California and Nevada. However, the decrees only

quantify individual water rights of parties to the litigation and did not address rights perfected under state

USBR’s Prosser Creek

Reservoir is one of the

Truckee River system

reservoirs whose operation

would be covered

by the TROA.

law by others—not all existing water uses are necessarily covered in the decrees. PL 101-618 established an

interstate allocation in the Carson River Basin; the California allocation corresponds to existing water uses.

Local Water Resources

Management Issues

Truckee River Operating Agreement

Negotiation of a proposed Truckee River Operating Agreement and preparation of its draft EIR/EIS

have been the major water management activities in

the region. A new operating agreement for the Truckee

River is required by PL 101-618. Negotiation of a proposed TROA and preparation of an EIR/EIS for the

TROA began in 1991. The draft EIR/EIS was released

for public review in 1998 and is expected to be completed in 1999.

PL 101-618 settled years of disputes over Truckee

and Carson River waters by making an interstate allocation between California and Nevada. It also settled

certain tribal water right claims and provided for water supplies for specified environmental purposes in

Nevada. The act allocated 23 taf annually to California in the Lake Tahoe Basin and 32 taf annually in the

Truckee River Basin below Lake Tahoe. The act allocated water corresponding to existing Carson River

Basin water uses to California. The remainder of the

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Truckee and Carson River supply was allocated to

Nevada.

When executed, the TROA would establish river

operations procedures to meet water rights on the

Truckee River and to enhance spawning flows in the

lower Truckee River for cui-ui and Lahontan cutthroat

trout. TROA would provide for management of water

within the Truckee Basin in California, including

instream flow requirements and reservoir storage for

fishery and recreation uses, and would include procedures for coordinating releases and exchanges of water

among the watershed’s reservoirs. TROA would become the exclusive federal regulation governing releases

of water stored in Lake Tahoe, Martis Creek, Prosser

Creek, Stampede, and Boca Reservoirs. The agreement

would provide an accounting procedure for surface and

groundwater diversions in California’s part of the

Truckee Basin and would establish criteria to minimize short-term reductions in river flow potentially

caused by future well construction near the river.

In 1993, an agreement was signed by Sierra Pacific Power Company, Washoe County Water

Conservation District, and Sierra Valley Water Company settling a dispute about when the water company

was required to stop diverting water from the Little

Truckee River. This agreement, which resolves disputes

that had often occurred during droughts, is being incorporated into the proposed TROA.

Walker River

Recent activities in the Walker River Basin have

focused on the declining level of Walker Lake in Nevada and the resulting impact on the lake’s fishery.

Because Walker Lake is a terminal sink, salts accumulate as the lake water evaporates. Declining lake levels

have resulted in most Great Basin terminal sinks being too saline to support fisheries. Walker Lake is one

of three terminal lakes in Nevada that support fish life.

The water level at Walker Lake has declined from an

elevation of about 4,080 feet in 1882 to 3,944 feet in

1994; salinity has increased during the same period

from about 2,500 mg/L TDS to 13,300 mg/L TDS.

In most years, Walker River is the primary source

of inflow to Walker Lake. Flow in the river comes from

runoff in the Sierra in California. Upstream agricultural diversions have contributed to reduced inflows,

resulting in a declining lake level and increased lake

salinity. If the trend continues, the Lahontan cutthroat

and the tui chub (an important food source for the

trout) may not be able to survive in the lake. To maintain lake salinity at the current level, about 33 taf/yr

more inflow is needed. Even with a stable lake level,

salinity will slowly increase because Walker Lake has

no natural outlet. A solution to Walker Lake problems

could affect water users in California and Nevada.

Potential tribal water rights claims on the Nevada side

of the basin could also affect existing water users.

Lake Tahoe

Lake Tahoe’s clarity has been declining as increasing development around the shoreline increases the

sediment load and nutrients reaching the lake. Nutrients, such as nitrogen and phosphorous used in lawn

or golf course fertilizers, can enter the lake in the form

of storm water runoff. Nutrients promote growth of

algae, reducing clarity. Clarity of lakes is measured by

the depth to which a Secchi disk, a small plastic disk

of specific size, is visible. In the late 1960s, average

Secchi disk visibility in Lake Tahoe was about 100 feet.

Now the figure is closer to 70 feet.

Programs to manage Lake Tahoe water quality by

regulating development and preventing pollutants from

reaching the lake are being implemented at the federal, state, and local levels. The Tahoe Regional

Planning Agency, a bistate agency created by Congress,

sets regional environmental standards, issues land use

permits (including conditions to protect water quality), and takes enforcement actions throughout the

basin. TRPA’s regional plan provides for achievement

and maintenance of environmental targets by managing growth and development. In addition to its

regulatory activities, TRPA carries out a capital improvement program to repair environmental damage

done before its regional plan was adopted. TRPA has

identified nearly $500 million in capital improvements

needed to achieve environmental targets. Federal, state,

and local governments have invested nearly $90 million in erosion control, storm water drainage, stream

zone restoration, public transit, and other capital

projects. Over 70 percent of the land in the Tahoe Basin

is controlled by the USFS’s Lake Tahoe Basin Management Unit. The LTBMU has implemented a

watershed restoration program and a land acquisition

program to prevent development of sensitive private

lands.

In recent years, federal and state agencies have increased funding to protect the environment of Lake

Tahoe. The State of Nevada approved a $20 million

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bond measure to perform erosion control and other

measures on the east side of the lake. In California,

Proposition 204 provides $10 million in bond funds

for land acquisition and programs to control soil erosion, restore watersheds, and preserve environmentally

sensitive lands.

Leviathan Mine

Leviathan Mine, an abandoned sulfur mine located

in Alpine County, is one of the most significant abandoned mine sites in the region. From 1863 to 1952,

operations at the site involved tunnel mining. Later,

the site was converted to an open-pit operation. Under this operation, tailings and overburden material

were placed in (or washed into) streams, creating water pollution problems with acid mine drainage and

metals. The mine was ultimately abandoned, leaving

an open pit, waste and spoil areas, and surface water

drainage and erosion problems. Neither the owner nor

the county had the resources to clean up the site.

In 1980, SWRCB approved a pollution abatement

project for Leviathan Mine. The remediation project

included channeling Leviathan Creek, filling and regrading the mine pit, excavating and regrading the

waste dump, creating onsite evaporation ponds, regrading the spoil areas, and improving drainage. The State

acquired the site in 1983 and the project was completed in 1985. Although the project reduced the

amount of acid mine drainage reaching the creek, contamination problems still occur today from pond

overflows, acidic springs, seepage, and erosion. The

RWQCB is currently involved in activities to further

reduce the pollution.

Sierra Nevada Ecosystem Project

The Sierra Nevada Ecosystem Project was an assessment of forests, key watersheds, and significant

natural areas on federal lands. In 1996, the University

of California released its Sierra Nevada Ecosystem Study,

the result of a three year, congressionally-mandated

study of the entire Sierra Nevada, with primary emphasis on gathering and analyzing data to assist

Congress in future management of the mountain range.

The study stated that “excluding the hard-to-quantify

public good value of flood control and reservoir-based

recreation, the hydroelectric generating, irrigation, and

urban use values of water are far greater than the combined value of all other commodities produced in the

Sierra Nevada.” The report estimated the value of water at 60 percent of that of all commodities produced

in the foothills and mountains of the Sierra Nevada.

January 1997 Flood Event

The January 1997 flood was among the most significant floods on record in the North Lahontan

Region. Lake Tahoe recorded its highest level since

1917 at an elevation of 6,229.39 feet. This elevation

was the lake’s highest since the 1935 Truckee River

Agreement, which limited the operating range of Lake

Tahoe’s surface elevation to between 6,223.0 feet (its

natural rim) and 6,229.1 feet. Flood damage occurred

along the Truckee’s channel immediately downstream

from the lake, although the greatest economic damages occurred in the Reno-Sparks area. In California,

flooding in downtown Truckee caused the closure of

major highways. Downstream from Truckee, the river

washed away Floriston Dam, a diversion dam used by

Sierra Pacific Power Company to divert water to its

run-of-river hydroelectric plant at Farad.

Stream flows along the Carson and Walker River

systems exceeded previous flood records. Flows along

the East Fork Carson River at Markleeville and West

Fork Carson River at Woodfords peaked at 21,000 cfs

and 8,000 cfs, respectively, considerably above the

record peak flows attained in 1963 and in excess of a

100-year flood event for these reaches of the river. The

East Walker River near Bridgeport and West Walker

River near Coleville peaked at 1,810 cfs and 6,220 cfs,

respectively, also above previously record flows. In

Mono County, about 8 miles of U.S. Highway 395

were washed out, isolating the communities of Coleville

and Walker. At the lower mouth of the Walker Canyon, homes and properties in the community of Walker

were damaged when the West Walker River spilled its

banks.

Water Management Options

for the North Lahontan Region

Table 9-4 shows a list of options for the region,

and the results of an initial screening of the options.

The retained options were evaluated (Table 9A-1 in

Appendix 9A) based on a set of fixed criteria discussed

in Chapter 6. Potential options to augment water supplies during drought conditions are water conservation,

groundwater pumping, and reservoir construction.

Land is idled during droughts if water is not available.

In Mono County, cutbacks in surface water deliveries

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TABLE 9-4

North Lahontan Region List of Water Management Options

Option Retain Reason for Deferral

or Defer

Conservation

Urban

Outdoor Water Use to 0.8 ETo Retain

Indoor Water Use Retain

Interior CII Water Use Defer No significant depletion reductions attainable.

Distribution System Losses Defer No significant depletion reductions attainable.

Agricultural

Seasonal Application Efficiency Improvements Defer No significant depletion reductions attainable.

Flexible Water Delivery Defer No significant depletion reductions attainable.

Canal Lining and Piping Defer No significant depletion reductions attainable.

Tailwater Recovery Defer No significant depletion reductions attainable.

Modifying Existing Reservoirs/Operations

— ——

New Reservoirs/Conveyance Facilities

Petes Valley Reservoir Defer High costs.

Willard Creek Reservoir Defer High costs.

Goat Mountain Reservoir Defer High costs.

Crazy Harry Gulch Reservoir Defer High costs.

Honey Lake Dike and Reservoir Defer Water quality inadequate for agriculture. Very low

yields with large estimated capital costs.

Long Valley Creek Reservoir Defer Very little firm yield.

Hope Valley Reservoir Defer High costs.

Leavitt Meadows Reservoir Defer Site is located on the West Walker River, upstream

of a reach designated as wild and scenic. Also

subject to interstate water issues with Nevada.

Pickle Meadow Reservoir Defer Same concerns as Leavitt Meadows site.

Roolane Reservoir Defer Same concerns as Leavitt Meadows site.

Mountain Lakes Reservoir Defer Same concerns as Leavitt Meadows site.

Groundwater/Conjunctive Use

Agricultural Groundwater Development Retain

Eastside Warner Mountain Recharge Defer DFG concerns about potential wildlife impacts

have diminished local interest in a pilot program

and/or reconnaissance level planning study.

Water Marketing

— ——

Water Recycling

Water recycling options Defer Water recycling options would not generate new

water supply in this region.

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9-11 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

during the recent drought resulted in pasture not being irrigated.

Water Conservation

Urban. Urban water demand forecasts for 2020

assume that BMPs are in place; consequently, only

those urban conservation efforts which exceed BMPs

are considered as options. Urban conservation options

in this region provide little potential for depletion reductions. Reducing outdoor water use to 0.8 ETo in

new and existing development would only conserve

about 1 taf/yr. Likewise, reducing indoor water use to

55 gpcd would conserve about 1 taf/yr.

Agricultural. The 2020 agricultural water demand

forecasts assume that EWMPs are in place. As with

the urban water management options, only those agricultural conservation efforts which exceed EWMPs

are considered as options. The efficiency of border irrigation systems used for alfalfa and pasture can be

improved through leveling fields and better managing

applications. No significant depletion reductions are

expected in the region, however, since most alfalfa irrigation occurs in Honey Lake Valley where excess

applied irrigation water recharges the groundwater basin.

New Reservoirs or Conveyance Facilities

 In 1992, the Department investigated six potential

reservoir sites in Lassen County that could provide up to

20 taf of storage. Sites were located on the Susan River,

Willow Creek, and Long Valley Creek. An analysis of

project costs indicates that the reservoirs were not economically feasible for agricultural water users in the region.

In the late 1950s and early 1960s, the Department examined potential reservoir sites in Mono

County that could serve agricultural lands in California. USBR, USGS, NRCS, and WRID have studied

these and other potential sites in California that could

provide water for Nevada uses. Projects that serve Nevada only are not included as options. The four

potential sites in Mono County located on the West

Walker River have similar economic constraints as the

sites in Lassen County. They are also subject to interstate

water rights concerns.

Groundwater Development

or Conjunctive Use

Although groundwater is available in the larger

valleys used for irrigated agriculture, water needs are

usually met from surface water. Groundwater cannot

be economically used to replace surface water uses because of pumping costs.

Modoc County Resource Conservation District

investigated groundwater recharge on six creeks which

drain the east slopes of the Warner Mountains in Surprise Valley. This project would recharge the alluvial

fans using existing stream channels or constructed recharge facilities. Experimental construction of recharge

areas on one or two of the creeks was proposed, but

potential environmental impacts and lack of funding

prevented implementation. This option was deferred.

TABLE 9-4

North Lahontan Region List of Water Management Options (continued)

Option Retain Reason for Deferral

or Defer

Desalting

Brackish Groundwater

— — —

Seawater

— — —

Other Local Options

— — —

Statewide Options

— — —

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TABLE 9-6

Options Most Likely to be Implemented by 2020 (taf)

North Lahontan Region

Average Drought

Applied Water Shortagea 10 128

Options Likely to be Implemented by 2020

Conservation — —

Modify Existing Reservoirs/Operations — —

New Reservoirs/Conveyance Facilities — —

Groundwater/Conjunctive Use — —

Water Marketing — —

Recycling — —

Desalting — —

Other Local Options — —

Statewide Options — —

Expected Reapplication — —

Remaining Applied Water Shortage 10 128

a Majority of shortages in this region are agricultural.

Options Likely to be Implemented

in the North Lahontan Region

Water supplies are not available to meet all of

the region’s 2020 water demands in average or

drought years. Applied water shortages are forecasted

to be 10 taf and 128 taf in average and drought

years, respectively. Ranking of retained water management options for the North Lahontan Region is

TABLE 9-5

Options Ranking for North Lahontan Region

Option Rank Cost ($/af) Potential Gain (taf)

Average Drought

Conservation

Urban

Outdoor Water Use to 0.8 ETo

– New and Existing Development M a 1 1

Indoor Water Use (55 gpcd) M 600 1 1

Groundwater/Conjunctive Use

Agricultural Groundwater Development M aaa

a Data not available to quantify.

summarized in Table 9-5. Table 9-6 summarizes options that can likely be implemented by 2020 to relieve

the shortages.

Although groundwater could be developed to help

meet drought year water needs, it is not ranked highly

due to its cost. During droughts, pasture irrigation will

probably continue to be curtailed.

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FIGURE 9-3

South Lahontan Hydrologic Region

MONO

INYO

SAN BERNARDINO

KERN

LOS ANGELES

N E V A D A 

M O J A V E D E S E R T

Grant

Lake

Lake

Crowley

Amar

River

Fairmont

Reservoir

Haiwee

Reservoir

River

Mono

Lake

Mo

River

Silverwood

Lake

Owens

jave

gosa

Los Angeles

Aqueduct

West Branch of

California Aqueduct East Branch of

California Aqueduct

Silver

Lake

Soda

Lake

Tinemaha

Reservoir

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Description of the Area

The South Lahontan Region encompasses the area

from the drainage divide between the Walker River

and Mono Lake Basin to the divide south of the Mojave

River (Figure 9-3). The region is bordered on the east

by the Nevada stateline and on the west by the crest of

the southern Sierra Nevada and San Gabriel Mountains. The region includes all of Inyo County and parts

of Mono, San Bernardino, Kern, and Los Angeles

Counties. Prominent geographic features of the region

are Owens Valley and Death Valley. The region contains the highest and lowest points in the lower 48

states—Mount Whitney (elevation 14,495 feet) and

Death Valley (elevation 282 feet below mean sea level).

 The region includes several closed drainage basins and many desert valleys containing central playas,

or dry lakes. Major waterbodies in the region are, from

north to south, Mono Lake, Owens River, and Mojave

River. The Amargosa River contains water only during rare flash floods. Floodwaters in the Amargosa River

would eventually flow south to a sink area at the Silver

Lake and Soda Lake Playas. This sink area is also the

terminus of the Mojave River, which flows eastward

from its headwaters in the San Bernardino Mountains

across the Mojave Desert to the playa lakes. Average

annual precipitation for the region’s valleys ranges between 4 and 10 inches. Death Valley receives only

1.9 inches annually. The Sierra Nevada can receive up

to 50 inches annually, much of it in the form of snow.

In some years, the community of Mammoth Lakes can

have snow accumulations of more than 10 feet.

The Joshua Tree,

a member of

the yucca family,

is endemic to the

Mojave Desert.

. . .

South Lahontan

Hydrologic Region

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Although sparsely populated, the region contains

some rapidly growing urban areas, including the Cities of Lancaster and Palmdale in Antelope Valley (Los

Angeles County) and the Cities of Victorville, Hesperia,

and Apple Valley in San Bernardino County. Many

residents in these areas have chosen a long commute

to the greater Los Angeles area in exchange for affordable housing. Future population growth in the region

is expected to be concentrated in communities within

commuting distance of the Los Angeles area. Bishop,

Ridgecrest, and Barstow are other population centers

in the region. The economies of these and other small

towns in the eastern part of the region are tied to the

region’s military facilities and other governmental employers, and to providing services for travelers and tourists.

Public lands constitute about 75 percent of the

region’s area, providing a major recreational resource.

Popular destinations in the region include the Mono

Lake area, June Lakes and Mammoth Lakes, Inyo

National Forest, Death Valley National Monument,

and the recently created Mojave National Preserve.

Only about 1 percent of the region’s land is used for

urban and agricultural purposes. Most of the irrigated

acreage, primarily alfalfa and pasture, is in the

Mono-Owens PSA. (This PSA includes Owens Valley, the Lake Crowley area northwest of Bishop, and

Hammil and Fish Lake Valleys.) Some deciduous orchard acreage is found in the western part of the region.

Table 9-7 shows population and crop acreage for the

region.

Major perennial waterbodies in the region are

Mono Lake and Owens River. Since relatively little

surface water is available in the rest of the region, the

region’s environmental water use is concentrated in the

Mono Lake-Owens Valley corridor. The major environmental water use requirements are associated with

maintenance of Mono Lake levels and fishery instream

flow requirements for the Owens River system. DFG

operates four fish hatcheries in the Mono-Owens area:

Mt. Whitney, Big Springs, Hot Creek, and Black Rock

Hatcheries.

The largest surface water development in the region is the Los Angeles Aqueduct and its associated

facilities, described in the following section. There are

also a few relatively small, high-elevation dams operated by Southern California Edison for

nonconsumptive hydropower purposes. These dams

do not provide water supply for the region. SWP’s

75 taf Lake Silverwood on the East Branch of the California Aqueduct regulates and stores imported water.

Water Demands and Supplies

 The water budget for the South Lahontan Region is shown in Table 9-8. Increased environmental

water demands from recently settled court actions involving LADWP’s water diversions from the Owens

Valley and Mono Lake are reflected in the base water

budget. A pending order issued by an air pollution

control district in 1997 could increase environmental

water demands in the region. This increase is not included in the water budget because final action has

not yet been taken (see the local water resources management issues section).

Los Angeles Aqueduct

The Los Angeles Aqueduct is the region’s major

water development feature, although it does not serve

water to the region. In 1913, the first pipeline of LAA

was completed and began conveying water from Owens

Valley to the City of Los Angeles. The aqueduct was

The Owens River, with the Sierra Nevada in the background. extended north of the Mono Basin and diversions beTABLE 9-7

Population and Crop Acreage

Population Irrigated Crop Acreage

(thousands) (thousands of acres)

1995 713 61

2020 2,019 45

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gan in 1940. A second pipeline was completed in 1970,

increasing the aqueduct’s annual delivery capacity to

about 550 taf/yr. Both aqueducts terminate at the 10

taf Los Angeles Reservoir in the South Coast Region.

The first aqueduct begins at the intake on Lee Vining

Creek and the second begins at Haiwee Reservoir.

There are eight reservoirs in the LAA system with

a combined storage capacity of about 323 taf (Table

9-9). These reservoirs were constructed to store and

regulate flows in the aqueduct. The northernmost reservoir is Grant Lake in Mono County. Six of the eight

reservoirs are located in the South Lahontan Region.

Bouquet and Los Angeles Reservoirs are in the South

Coast Region.

Water from both aqueducts passes through 12

powerplants on its way to Los Angeles. The annual

energy generated is over 1 billion kWh, enough to supply the needs of 220,000 homes.

State Water Project

The East Branch of the California Aqueduct follows the northern edge of the San Gabriel Mountains,

bringing imported water to Silverwood Lake. Table 9-

10 shows SWP contractors in the region and their

contractual entitlements.

Antelope Valley-East Kern Water Agency, the largest SWP contractor in the region, serves 5 major and

16 small municipal agencies, as well as Edwards AFB,

Palmdale Air Force Plant 42, and U.S. Borax and

Chemical Facilities. AVEK was formed to bring imported water into the area.

Mojave Water Agency was created in 1960 in response to declining groundwater levels in the area.

Communities within MWA’s boundaries have no

source of supply other than groundwater. CommuniTABLE 9-8

South Lahontan Region Water Budget (taf)a

1995 2020

Average Drought Average Drought

Water Use

Urban 238 238 619 619

Agricultural 332 332 257 257

Environmental 107 81 107 81

Total 676 651 983 957

Supplies

Surface Water 322 259 437 326

Groundwater 239 273 248 296

Recycled and Desalted 27 27 27 27

Total 587 559 712 649

Shortage 89 92 270 308

a

 Water use/supply totals and shortages may not sum due to rounding.

TABLE 9-9

Los Angeles Aqueduct System Reservoirs

Reservoir Capacity (taf) County

Grant 47 Mono

Crowley 183 Mono

Pleasant Valley 3 Inyo

Tinemaha 6 Inyo

Haiwee 39 Inyo

Fairmont 0.5 Los Angeles

Bouquet 34 Los Angeles

Los Angeles 10 Los Angeles

TABLE 9-10

SWP Contractors in the South Lahontan Region

Contractor Annual Entitlement (taf) 1995 Deliveries (taf)

Antelope Valley-East Kern WA 138.4 47.3

Crestline-Lake Arrowhead WA 5.8 0.4

Littlerock Creek ID 2.3 0.5

Mojave WA 75.8 8.7

Palmdale WD 17.3 7.0

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-18

ties served by MWA include Barstow, Apple Valley,

Hesperia, and Victorville. While most of MWA’s service area is within the South Lahontan Region, the

service area extends into the Colorado River Hydrologic Region (the Lucerne and Johnson Valleys and

the Morongo Basin). Part of MWA’s SWP entitlement

(7.3 taf) is allocated to that area.

MWA has taken little of its SWP entitlement to

date, due to lack of conveyance facilities. In 1994,

MWA completed its Morongo Basin pipeline, a 71-

mile pipeline with a capacity of 100 cfs from the SWP’s

East Branch to the Mojave River (7 miles) and then

20 cfs to Morongo Basin and Johnson Valley. This pipeline allows MWA to bring SWP water into part of its

large (almost 5,000 square miles) service area. In 1997,

MWA began construction of its 71-mile Mojave River

Pipeline (94 cfs capacity) to bring imported water to

Barstow and neighboring cities. The El Mirage Aqueduct is the next proposed addition to its distribution

system. The aqueduct would deliver approximately 4

taf of imported water annually from the East Branch

to the westernmost subarea of the Mojave River Basin

near El Mirage. Imported water would be used to recharge the area’s overdrafted groundwater basin.

In 1997, MWA and Berrenda Mesa Water District (a member agency of KCWA) concluded the

permanent transfer of 25 taf of SWP annual entitlement, thereby increasing MWA’s total annual

entitlement to 75.8 taf.

Local Surface Water Supplies

The Mammoth Community Water District supplies the town of Mammoth Lakes, located at the

northern end of the region. About 70 percent of

MCWD’s supply comes from Lake Mary, the largest

of a number of small alpine lakes in the Mono Lakes

Basin. At present, the remainder of MCWD’s supply

comes from groundwater. Although MCWD serves a

permanent population of only about 5,000 people, its

average daily population is about 13,000, with peak

weekends and holiday periods reaching 30,000 people

per day. These wide fluctuations in service levels above

the base population are typical of the recreational and

resort communities in the area.

Although the Mojave River appears on maps as a

major waterway in the region, it is an ephemeral stream

for much of its length. Local communities extract

groundwater, which is recharged by river flows, but

do not directly divert significant amounts of surface

water from the river. There is one dam on the Mojave

River at the base of the San Bernardino Mountains—

Mojave River Forks Dam, a 90 taf USACE flood

control facility.

The 3.5 taf capacity Littlerock Reservoir provides

water supply to Littlerock Creek Irrigation District and

to Palmdale Water District. PWD funded most of a

recent seismic rehabilitation of the 1924-vintage dam

in exchange for control of the water supply for 50 years.

Water from Littlerock Reservoir may be released into

a ditch that conveys flows to PWD’s Lake Palmdale, a

4.2 taf storage reservoir.

In the San Bernardino Mountains, Lake Arrowhead, owned by the Arrowhead Lake Association, is a

48 taf reservoir providing recreational opportunities

and water supply for lakeshore residents.

Groundwater Supplies

Historically the South Lahontan Region has relied mostly on groundwater, which is the only water

supply available in most parts of the region. Groundwater basin capacities in the Mojave River and Antelope

Valley PSAs, for example, total about 70 maf each.

(Economically usable storage is significantly less than

this amount.) Water quality influences groundwater

use. Some areas in the Mono-Owens area have highly

mineralized groundwater due to geothermal activity,

while saline groundwater is not uncommon in areas

near playa lakes.

The Mojave River groundwater basin is a large

alluvial formation in the Mojave Desert, the only local

Littlerock Reservoir is one of the few surface water storage

facilities in the Mojave Desert area. The original dam at this

site was a multi-arch concrete structure. This photo shows the

dam after its seismic rehabilitation.

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9-19 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

water source for residents in the western third of San

Bernardino County (part of the basin is in the Colorado River Region). The Mojave River and

groundwater basin act as one water source, with the

river recharging the basin and groundwater discharging in several places to provide surface flows in the

river. The basin is divided into subareas at

hydrogeologic boundaries including the Helendale and

Waterman Faults. The operational storage capacity of

the basin is about 4.9 maf; currently there is about

3.0 maf of water in storage. The basin has experienced

declining groundwater levels due to overextractions (see

Mojave River adjudication section).

The Antelope Valley groundwater basin underlies

the closed drainage in the westernmost part of the

Mojave Desert in northern Los Angeles and southeastern Kern Counties. It provides most of the local water

supplies to users in the high desert from the San Gabriel

Mountains to the Sierras, including Edwards Air Force

Base. Agricultural pumping from the basin has declined

for several decades while urban extraction has increased

due to rapid population growth.

Local Water Resources

Management Issues

Owens Valley Area

In 1972, Inyo County filed suit against the City

of Los Angeles, claiming that increased groundwater

pumping for the second aqueduct was harming the

Owens Valley environment. Inyo County asked that

LADWP’s groundwater pumping be analyzed in an

Surface water is found in

most desert waterways only

after infrequent storms. If

local groundwater resources

are not sufficient to supply

an area’s needs, water must

be imported to augment local

supplies. This photo shows

the Mojave River bed at

Red Rock Canyon.

Searles Lake

The Mojave Desert has numerous playa lakes, dry or

semi-dry lakebeds that occupy topographic low points in

closed drainage basins. Playa lakes contain surface water

only briefly after the region’s infrequent rains. There

may, however, be high groundwater levels immediately

beneath an apparently dry lakebed. Groundwater found

near these lakebeds is usually too mineralized for most

beneficial uses, because salts have been concentrated in

lakebed deposits during evaporation of the surface

waters. Searles Lake in northwestern San Bernardino

County is an example of an extremely mineralized playa

lake.

Within geologic time, California’s climate was much

wetter than it is today. During the late Quaternary

Period, the Owens River flowed into several (now dry)

lakes in the Mojave Desert, filling Searles Lake to a depth

of over 600 feet. Long-term deposition of evaporates in the

lakebed created thick layers of salts and borate minerals.

These deposits have been the basis of extensive mining

operations at the lake, estimated to have produced more

than $1 billion worth of mineral commodities.

Borax mining at the lakebed began as early as 1874.

Current mining techniques entail pumping brines from

lakebed sediments and processing them at onsite chemical

plants to produce commodities such as sodium carbonate,

sodium borate, and sodium sulfate. These chemicals are

used in the manufacture of drugs, dyes, glass, glazes, paper,

soap, detergent, enamel, chemical products, abrasives,

gasoline additives, fire retardants, and metal alloys.

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-20

EIR. LADWP prepared an EIR in 1976 and another

in 1979, both of which the Third District Court of

Appeals found inadequate. In 1983, Inyo County and

LADWP decided to work together to develop an EIR

and water management plan to settle the litigation.

A third EIR was prepared jointly by LADWP and

Inyo County and released in 1990. In 1991, both parties executed a long-term water management agreement

delineating how groundwater pumping and surface

water diversions would be managed to avoid significant decreases in vegetation, water-dependent

recreational uses and wildlife habitat. Several entities

challenged the adequacy of the EIR and in 1993 were

granted amici curiae status by the Court of Appeals,

allowing them to enter in the EIR review process. An

agreement was subsequently executed in 1997, ending 25 years of litigation between Los Angeles and Inyo

County.

LADWP and Inyo County have begun discussions

on how to implement provisions of the agreements

and EIR. Timelines for many provisions have already

been developed and plans for major activities such as

rewatering the Lower Owens River are under review.

Surface water diversions for Owens Valley agriculture from the Owens River began in the 1800s. The

Los Angeles Aqueduct was completed in 1913. Owens

Lake became a dry lakebed by 1929. On windy days,

airborne particulates from the dry lakebed violate air

quality standards in the southern Owens Valley. In

1997, the Great Basin Unified Air Pollution Control

District ordered the City of Los Angeles to implement

control measures at Owens Lake to mitigate the dust

problems. Under the order, 8,400 acres of lakebed

would be permanently flooded with a few inches of

water, another 8,700 acres would be planted with grass

and irrigated, and 5,300 acres would be covered with

a four-inch layer of gravel. This order could reduce

the city’s diversions by 51 taf/yr or about 15 percent

of its supply. In July 1998, a compromise was reached

when LADWP agreed to begin work at Owens Lake

by 2001 and to ensure that federal clean air standards

would be met by 2006. In turn, the APCD agreed to

scale back the improvements sought in its 1997 order.

Under this agreement, LADWP’s dust-control strategy may include shallow flooding, vegetation planting,

and gravel placement. The implementation schedule

requires that 6,400 acres of lakebed be treated by the

end of 2001. By the end of 2006, an additional 8,000

acres would be treated, plus any additional lakebed

necessary to bring particulate counts into compliance

with federal air quality standards. The plan hinges on

final approval from the Los Angeles City Council, the

APCD’s board, and the State Air Resources Board. The

agreement also requires EPA to grant a 5-year extension of Clean Air Act requirements that direct states

to abate particulate pollution by 2001 or seek an extension until 2006.

Mono Basin

Mono Lake, located east of Yosemite National Park

at the base of the eastern Sierra Nevada, is the second

largest lake completely within California. It is recognized as a valuable environmental resource. The lake

is famous for its tufa towers and spires, structures

formed by years of mineral deposition by its saline

waters. The lake has no outlet. There are two islands

in the lake that provide a protected breeding area for

large colonies of California gulls and a haven for migrating waterfowl.

Much of the water flowing into Mono Lake comes

from snowmelt runoff. Since 1941, LADWP has diverted water from Lee Vining, Walker, Parker, and Rush

Creeks into tunnels and pipelines that carry the water

to the Owens Valley drainage. There it is conveyed,

together with Owens River flows, to Los Angeles via

the LAA.

Diversions from its tributaries lowered Mono

Lake’s water level from elevation 6,417 feet in 1941 to

a historic low of 6,372 feet in 1981. With decreased

inflow of fresh water, the lake’s salinity increased dramatically. When water levels drop to 6,375 feet or

lower, a land bridge to Negit Island is created, allowing predators to reach gull rookeries; this first happened

in 1978 and again during the 1987-92 drought.

As a result of these impacts, the lake and its tributaries have been the subject of extensive litigation

between the City of Los Angeles and environmental

groups since the late 1970s. In 1983, the California

Supreme Court ruled that SWRCB has authority to

reexamine past water allocation decisions and the responsibility to protect public trust resources where

feasible. SWRCB issued a final decision on Mono Lake

(Decision 1631) in 1994. The amendments to

LADWP’s water right licenses are set forth in the order accompanying the decision.

The order sets instream flow requirements for fish

in each of the four streams from which LADWP diverts water. The order also establishes water diversion

criteria to protect wildlife and other environmental

resources in the Mono Basin. These water diversion

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9-21 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

criteria prohibit export of water from Mono Basin until

the lake level reaches 6,377 feet, and restrict Mono

Basin water exports to allow the lake level to rise to an

elevation of 6,391 feet in about 20 years. Once the

water level of 6,391 feet is reached, it is expected that

LADWP will be able to export about 31 taf/yr of water from the basin. The order requires LADWP to

prepare restoration plans for the four streams from

which it diverts and to restore part of the waterfowl

habitat which was lost due to lake level decline. In May

1997, parties to the restoration planning process presented a signed settlement on Mono Basin restoration

to the SWRCB. If approved, the settlement would

guide restoration activities and annual monitoring

through 2014. Parties to the settlement include

LADWP, the Mono Lake Committee, DFG, State

Lands Commission, DPR, California Trout, National

Audubon Society, USFS, BLM, and The Trust for

Public Land.

Key features of stream restoration plan include

restoring peak flows to Rush, Lee Vining, Walker, and

Parker Creeks; reopening abandoned channels in Rush

Creek; and developing a monitoring plan. One of the

restoration actions required by SWRCB—bypassing

sediment around LADWP diversion dams—was deferred for further analysis. The waterfowl habitat

restoration plan proposes that a Mono Basin waterfowl habitat restoration foundation administer a $3.6

million trust established by LADWP. Five of the parties to the agreement would serve as initial members

of the foundation. Activities would include annual

monitoring, restoring open water habitat adjacent to

the lake, and rewatering Mill Creek. LADWP would

continue its brine shrimp productivity studies, open

several channels on Rush Creek, and make its Mill

Creek water rights available for rewatering Mill Creek,

based on the recommendations of the foundation.

The plans are being considered by SWRCB and a

decision is expected at the end of 1998.

Mojave River Adjudication

The Mojave River groundwater basin has experienced overdraft since the early 1950s, with the largest

increase in overdraft occurring in the 1980s. About 80

percent of basin recharge comes from the Mojave River.

In 1990, the City of Barstow filed a complaint in Superior Court against the City of Adelanto seeking an

average annual guaranteed flow of 30 taf to mitigate

reduced runoff and declining groundwater levels in the

Barstow area. The complaint also requested a writ of

mandate against MWA to compel it to import water

from the SWP. MWA filed a cross-complaint requesting a determination of water rights in the basin.

In 1991, the court ordered that the litigation be

placed on hold to give parties time to negotiate a settlement and to develop a solution to the overdraft. A

Mojave Basin adjudication committee was formed to

facilitate data gathering and to draft a stipulated judgment and physical solution. The court’s final ruling

on basin adjudication was issued in January 1996. In

its ruling, the court emphasized that the area has been

in overdraft for decades and that MWA must alleviate

overdraft through conservation and purchase of supplemental water. MWA was appointed as the basin

watermaster.

The adjudication stipulated that any party pumping more than 10 af/yr became a party to the judgment

and is bound by it. The judgment stated that each party

has a right to its base annual production, which was

its highest usage between 1986 and 1990. The judgment also required MWA to reduce this amount by at

least 5 percent each year for four years as one way to

achieve a physical solution to the longstanding overdraft. Any party exceeding its annual allotment must

purchase replenishment water from MWA or from

other parties to the judgment. If there is still overdraft

after the end of the first five years of the stipulated

judgment, water use in overdrafted subareas will be

further reduced. The judgment recognized five basin

subareas and required that if an upstream subarea does

not meet its obligation to a downstream subarea, the

upstream area must pay for supplemental water.

Supplemental water for the Mojave River Basin

will come from MWA’s SWP entitlement, or from

water marketing arrangements, and will be delivered

through the California Aqueduct. In March 1997,

MWA began constructing its Mojave River pipeline,

extending about 71 miles from the California Aqueduct to Newberry Springs, a rural community east of

Barstow. MWA also recently purchased the permanent

right to 25 taf of additional SWP annual entitlement,

nearly a 50 percent increase from the agency’s previous entitlement. The combination of reduced

pumping, increased SWP deliveries and other imports,

and new delivery facilities are expected to reduce overdraft in the basin.

Antelope Valley Water Management

The Antelope Valley Water Group was formed in

1991 to provide coordination among valley water agenEE-RM-PET-100 C0MMENT 01A
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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-22

cies and other interested entities. AVWG members

include the Cities of Palmdale and Lancaster, Edwards

AFB, AVEK, Antelope Valley United Water Purveyors

Association, Los Angeles County Waterworks Districts,

PWD, Rosamond Community Services District, and

Los Angeles County. AVWG completed an Antelope

Valley water resources study in 1995 to address regional

water management issues.

The study evaluated the valley’s existing and future water supplies from groundwater, the SWP,

Littlerock Reservoir, and recycling, and compared these

supplies with projected water demands. The study concluded that water supply reliability is low in the study

area—full 1998 demands would be met only half the

time without overdrafting groundwater resources. The

study recommended water conservation, recycling, and

conjunctive use measures to reduce expected shortages.

The study identified three sites (two on Amargosa

Creek and one on Littlerock Creek) with high potential for groundwater recharge through spreading and

identified SWP water, recycled water, and local runoff

as potential recharge sources. The study also identified several potential groundwater injection sites within

existing Los Angeles County Waterworks and PWD

municipal wellfields. Treated SWP water was identified as a potential recharge source.

In 1996, PWD adopted a water facilities master

plan for its service area, updating a 1988 plan. PWD

relies on three water sources: Littlerock Reservoir, local groundwater, and SWP water. The plan indicates

that about 40 percent of PWD supply is from groundwater. Declining groundwater levels have been a local

concern in the Palmdale area, although extractions

presently appear to be within the basin’s perennial yield.

The plan also indicates that existing supplies are insufficient to meet drought demands. Average year

shortages are projected to occur by 2005.

To meet drought year demands, the plan calls for

the construction of up to 12 new production wells.

The plan’s draft EIR identified declining groundwater

levels as an unavoidable impact of constructing new

wells. Mitigation measures recommended included

conservation and drought year demand reduction, conjunctive use programs (as identified in the Antelope

Valley water resources study), acquisition of an additional 3.1 taf/yr of SWP entitlement, participation in

water transfers, and development of recycled water.

Interstate Groundwater Basins

California and Nevada share three interstate

groundwater basins in the South Lahontan Region:

Fish Lake Valley, crossed by Highway 168 east of

Westgard Pass; Pahrump Valley, located to the east of

Death Valley; and Mesquite Valley, just south of

Pahrump Valley. Groundwater extraction on the California side of the border supports small-scale

agricultural development, largely for alfalfa. Pahrump

Valley is the most populated of the three valleys; most

of its development is located in Nevada around the

community of Pahrump. Pahrump and Mesquite Valleys are within about 35 miles of the rapidly growing

Las Vegas metropolitan area. In the early 1990s, the

Southern Nevada Water Authority proposed exporting groundwater from several rural counties in central

Nevada to help meet Las Vegas’ rapidly increasing need

for water. Opposition by rural Nevada counties to

SNWA’s proposal caused SNWA to defer this project.

Inyo County residents have historically been concerned

about the proximity of Las Vegas to the interstate basins, although no new interstate issues have come up

since SNWA’s proposed project.

Water Management Options for the

South Lahontan Region

Table 9-11 shows a list of options for the region,

and the results of an initial screening of the options.

The retained options were evaluated (Table 9A-2 in

Appendix 9A) based on a set of fixed criteria discussed

in Chapter 6.

Water Conservation

Urban. Urban water demand forecasts for 2020

assume that BMPs are in place; consequently, only

those urban conservation efforts which exceed BMPs

are considered as options. Reducing outdoor water use

to 0.8 ETo in new development would attain 20 taf/yr

of depletion reductions, while extending this measure

to include existing development would reduce depletions by 31 taf/yr. Reducing residential indoor water

use to 60 and 55 gpcd would attain depletion reductions of 7 and 15 taf/yr, respectively. Reducing CII

water use by an additional 3 and 5 percent would attain 2 and 4 taf/yr of depletion reductions, respectively.

Reducing distribution system losses to 7 and 5 percent would save 4 and 12 taf/yr, respectively.

Agricultural. The 2020 agricultural water demand

forecasts assume that EWMPs are in place. As with

the urban water management options, only those agricultural conservation efforts which exceed EWMPs

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9-23 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

TABLE 9-11

South Lahontan Region List of Water Management Options

Option Retain Reason for Deferral

or Defer

Conservation

Urban

Outdoor Water Use to 0.8ETo Retain

Indoor Water Use Retain

Interior CII Water Use Retain

Distribution System Losses Retain

Agricultural

Seasonal Application Efficiency Improvements Retain

Flexible Water Delivery Defer No significant depletion reductions attainable.

Canal Lining and Piping Defer No significant depletion reductions attainable.

Tailwater Recovery Defer No significant depletion reductions attainable.

Modify Existing Reservoirs/Operations

Remove Sediment from Littlerock Reservoir Defer Excessive costs for additional yield.

New Reservoirs/Conveyance Facilities

— ——

Groundwater/Conjunctive Use

— ——

Water Marketing

Mojave Water Agency Retain

Palmdale Water District Retain

Water Recycling

Water recycling options Defer Water recycling options in this region do not

generate new water supply.

Desalting

Brackish Groundwater

— ——

Seawater

— ——

Other Local Options

Line Palmdale Ditch Defer No net increase in supply.

Reduce Outflow to Playa Lakes Defer Restrictions on use of flows that provide recharge

to overdraft basins. Costs are high and water

quality is poor.

Statewide Options

— — See Chapter 6.

are considered as options. It is estimated that water

savings of 2, 3, and 5 taf/yr could be achieved in this

region, by improving SAE to 76, 78, and 80 percent,

respectively. Options for flexible water delivery and

canal lining and piping are not feasible in this region

because most water supply comes from individual wells

with minimal conveyance facilities.

Modify Existing Reservoirs or Operations

Sediment has accumulated in Littlerock Reservoir

and minor additional yield could be realized by removing the sediment. Studies are now under way to

evaluate the costs and benefits of this option. Preliminary estimates indicate that the cost of this option is

in the order of $2,000/af. Because of the high costs,

this option was deferred.

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-24

New Reservoirs or Conveyance Facilities

There are no proposed new reservoir developments

in this region. The region’s aridity and consequent lack

of surface water resources make new reservoirs infeasible. Future local water resources development will

be based on groundwater sources.

Water Marketing

The California Aqueduct could convey purchased

water to MWA’s distribution system to supply some of

the region’s rapidly urbanizing areas. MWA has entered into a multi-year banking and exchange

agreement with Solano County Water Agency. During wet years, SCWA can bank up to 10 taf of its annual

SWP entitlement in MWA’s groundwater basin. During drought years, SCWA can take part of MWA’s SWP

entitlement in exchange (up to half the banked amount

with a maximum of 10 taf/yr). MWA is also pursuing

two demonstration water marketing projects of 2 taf

each. PWD is seeking to purchase 3.1 taf/yr of SWP

entitlement from Central Valley agricultural water

purveyors. Other voluntary marketing arrangements

could be developed through option agreements, storage programs, and purchases of water through the

DWB or other spot markets.

Capacity has been developed to store additional

imported supplies in the Mojave River Basin at MWA’s

Rock Springs groundwater recharge facility near

Hesperia. Additional recharge facilities in the Barstow

area are in the final planning stages, which would further increase MWA’s ability to take delivery of imported

supplies when its Mojave River Aqueduct is completed.

Sufficient basin storage is available to store water in

wet years when more SWP supplies or purchased supplies might be available.

Water Recycling

Water recycling options are deferred for this region because planned projects would not generate new

supply.

Other Local Options

The ditch that conveys water from Littlerock Reservoir to Palmdale Lake has an estimated 20 percent

conveyance loss, which could be reduced by canal lining. Canal lining would reduce groundwater recharge

by approximately 1 taf/yr, resulting in no net increase

in water supply. This option was deferred.

Some flow of the Mojave River reaches Soda Lake

where the flow is lost to evaporation. Annual outflow

past Afton Canyon averages 8.4 taf. However, the basin adjudication restricts use of flows that provide

recharge to downstream subareas of the basin that are

in overdraft. Reducing outflow to Soda Lake was deferred as an option.

Likewise, local storm runoff collects in many small

playas throughout the basin. These playas generally

do not contribute to groundwater recharge, due to the

low permeability of playa soils. Water collected in the

playas evaporates, rather than recharging groundwater. Diversion or collection of runoff to playas and

recharging it to groundwater basins could increase

groundwater supplies by eliminating the evaporation.

Six dry lakebeds could potentially store an additional

1.8 taf once every five years. Costs for this option are

$1,000 to $3,300/af. Water quality at the playas is generally poor, with high levels of salts and minerals. This

option was deferred.

Statewide Options

Statewide water supply augmentation options are

discussed and quantified in Chapter 6.

Options Likely to be Implemented

in the South Lahontan Region

Water supplies are not available to meet all of the

region’s 2020 water demands in average or drought

years. Applied water shortages are forecasted to be 270

taf in average years and 308 taf in drought years. Most

of the region’s shortage will be in the Mojave River

planning subarea. Water shortages in the Antelope

Valley subarea are forecast only in drought years. Ranking of retained water management options for the

South Lahontan Region is summarized in Table 9-12.

Table 9-13 summarizes options that can likely be implemented by 2020 to relieve the shortages. The options

likely to be implemented in this region include SWP

supplies and water transfers conveyed by the California Aqueduct.

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9-25 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

TABLE 9-13

Options Most Likely to be Implemented by 2020 (taf)

South Lahontan Region

Average Drought

Applied Water Shortage 270 308

Options Likely to be Implemented by 2020

Conservation 56 56

Modify Existing Reservoirs/Operations - -

New Reservoirs/Conveyance Facilities - -

Groundwater/Conjunctive Use - -

Water Marketing 7 6

Recycling - -

Desalting - -

Other Local Options - -

Statewide Options 174 204

Expected Reapplication 33 42

Total Potential Gain 270 308

Remaining Applied Water Shortage 0 0

TABLE 9-12

Options Ranking for South Lahontan Region

Optiona Rank Cost ($/af) Potential Gain (taf)

Average Drought

Conservation

Urban

Outdoor Water Use to 0.8 ETo

-New Development M 750 20 20

Outdoor Water Use to 0.8 ETo-New and Existing Development M b 31 31

Indoor Water Use (60 gpcd) M 400 7 7

Indoor Water Use (55 gpcd) M 600 15 15

Interior CII Water Use (3%) M 500 2 2

Interior CII Water Use (5%) M 750 4 4

Distribution System Losses (7%) M 200 4 4

Distribution System Losses (5%) M 300 12 12

Agricultural

Seasonal Application Efficiency Improvements (76%) H 100 2 2

Seasonal Application Efficiency Improvements (78%) M 250 3 3

Seasonal Application Efficiency Improvements (80%) M 450 5 5

Water Marketing

Mojave Water Agency H b 4 4

Palmdale Water District (3.1 taf SWP entitlement) H b 3 2

Statewide Options

See Chapter 6.

a

 All or parts of the amounts shown for highlighted options have been included in Table 9-13.

b Data not available to quantify.

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-26

FIGURE 9-4

Colorado River Hydrologic Region

RIVERSIDE

IMPERIAL

SAN BERNARDINO

SAN DIEGO A

R I Z

O

N A

M E X I C O

U T A H

wat

River

Coachella

Canal

Alamo

er

All

American

Canal

New

River

Lake

Havasu

Copper Basin

Reservoir

Gene Wash

Reservoir

River

Aqueduct

Colorado

River

Colorado

White er

Salton

Sea

Riv

Imperial

Dam

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Description of the Area

The Colorado River Region encompasses the

southeastern corner of California. The region’s northern boundary, a drainage divide, begins along the

southern edge of the Mojave River watershed in the

Victor Valley area of San Bernardino County and

extends northeast across the Mojave Desert to the Nevada stateline. The southern boundary is the Mexican

border. A drainage divide forms the jagged western

boundary through the San Bernardino, San Jacinto,

and Santa Rosa Mountains, and the Peninsular Ranges

(including the Laguna Mountains). The Nevada

stateline and the Colorado River (the boundary with

Arizona) delineate the region’s eastern boundary (Figure 9-4).

Covering over 12 percent of the total land area in

the State, the region is California’s most arid. It includes volcanic mountain ranges and hills; distinctive

sand dunes; broad areas of Joshua tree, alkali scrub,

and cholla communities; and elevated river terraces.

Much of the region’s topography consists of flat plains

punctuated by hills and mountain ranges. The San

Andreas fault traverses portions of the Coachella and

Imperial Valleys. A prominent topographic feature is

the Salton Trough in the south-central part of the region.

The climate for most of the region is subtropical

desert. Average annual precipitation is much higher in

the western mountains than in the desert areas. Winter snows generally fall above 5,000 feet; snow depths

can reach several feet at the highest levels during winter. Most of the precipitation in the region falls during

the winter; however, summer thunderstorms can produce rain and local flooding. Despite its dry climate

and rugged terrain, the region contains large and productive agricultural areas and popular vacation resorts.

Table 9-14 shows the region’s population and crop

acreage for 1995 and 2020.

TABLE 9-14

Population and Crop Acreage

Population Irrigated Crop Acreage

(thousands) (thousands of acres)

1995 533 749

2020 1,096 750

Coachella Valley date palms. The Colorado River Region is

the main location in California where dates are grown for

commercial production.

. . .

Colorado River

Hydrologic Region

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Most of the population is concentrated in the

Coachella and Imperial Valleys. Major cities in the

Coachella Valley include Palm Springs, Indio, and Palm

Desert. Other urban centers in the region are the Cities of El Centro, Brawley, and Calexico in Imperial

Valley; the Cities of Beaumont and Banning in the

San Gorgonio Pass area; and the Cities of Needles and

Blythe along the Colorado River.

Agriculture is an important source of income for

the region. Almost 90 percent of the developed private land is used for agriculture, most of which is in

the Imperial, Coachella, and Palo Verde Valleys. The

primary crops are alfalfa, winter vegetables, spring

melons, table grapes, dates, Sudan grass, and wheat.

Recreation and tourism are another important source

of income for the region. In Coachella Valley, the Palm

Springs area and adjoining communities are an important resort and winter golf destination. Recreational

opportunities provided by the more than 100 golf

courses in the Coachella Valley, water-based recreation

on the Colorado River and Salton Sea, and desert

camping all contribute to the area’s economy.

Water Demands and Supplies

Table 9-15 shows the water budget for the Colorado River Region. Agricultural water demand makes

up the majority of the water use in the region. There

are two major areas where water is used for wildlife

habitat in the region, the Salton Sea National Wildlife

Refuge and the Imperial Wildlife Area. There are also

several private wetlands.

About 90 percent of the region’s water supply is

from surface deliveries from the Colorado River

(through the All American and Coachella Canals, local diversions, and the Colorado River Aqueduct by

means of an exchange for SWP water). Other supplies

are from groundwater, SWP water, local surface water,

and recycled water. Bulletin 160-98 base year groundwater overdraft in the region was estimated to be about

70 taf and occurs in the Coachella Valley.

Major water agencies in the region are the Palo

Verde Irrigation District, Imperial Irrigation District,

Coachella Valley Water District, Bard Water District,

Mojave Water Agency, Desert Water Agency, and San

Gorgonio Pass Water Agency.

The region’s primary shortages with existing supplies are expected to occur in the Coachella planning

subarea because of groundwater overdraft. (In the future, reduction in California’s Colorado River water

use to the State’s basic apportionment creates an average year shortage of as much as 0.9 maf in the South

Coast Region. This 2020 shortage is shown in the

South Coast water budget.)

Supplies from the Colorado River

Most of the water supply in the region comes from

the Colorado River, an interstate (and international)

river whose use is apportioned among the seven Colorado River Basin states by a complex body of statutes,

decrees, and court decisions known collectively as the

law of the river. Table 9-16 summarizes key elements

of the law of the river. USBR acts as the watermaster

for the Colorado River, and all users of Colorado River

water must contract with USBR for their supplies. Figure 9-4 shows the locations of key Colorado River

storage and conveyance facilities.

TABLE 9-15

Colorado River Region Water Budget (taf)a

1995 2020

Average Drought Average Drought

Water Use

Urban 418 418 740 740

Agricultural 4,118 4,118 3,583 3,583

Environmental 39 38 44 43

Total 4,575 4,574 4,367 4,366

Supplies

Surface Water 4,154 4,128 3,920 3,909

Groundwater 337 337 285 284

Recycled and Desalted 15 15 15 15

Total 4,506 4,479 4,221 4,208

Shortage 69 95 147 158

a

 Water use/supply totals and shortages may not sum due to rounding.

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TABLE 9-16

Key Elements of the Law of the River

Document Date Main Purpose

Colorado River Compact 1922 Equitable apportionment of the water from the Colorado River system

between the two basins. The Upper Basin and the Lower Basin are each

provided a basic apportionment of 7.5 maf annually of consumptive use.

The Lower Basin is given the right to increase its consumptive use an

additional 1 maf annually.

Boulder Canyon Project Act 1928 Authorized USBR to construct Boulder (Hoover) Dam and the All

American Canal (including the Coachella Canal), and gave congressional

consent to the Colorado River Compact. Also provided that all users of

Colorado River water must enter into a contract with USBR for use of the

water.

California Limitation Act 1929 Limited California’s share of the 7.5 maf annually apportioned to the

Lower Basin to 4.4 maf annually, plus no more than half of any surplus

waters.

Seven Party Agreement 1931 An agreement among PVID, IID, CVWD, MWDSC, City of Los

Angeles, City of San Diego, and County of San Diego to recommend to

the Secretary of Interior how to divide use of California’s apportionment

among the California water users. Details are shown in Table 9-17.

U.S. - Mexican Treaty 1944 Guarantees Mexico a supply of 1.5 maf annually of Colorado River water.

U.S. Supreme Court Decree in 1964 Apportions water from the mainstream of the Colorado River among the

Arizona v. California, et al. Lower Division states. When the Secretary determines that 7.5 maf of

mainstream water is available, it is apportioned 2.8 maf to Arizona, 4.4

maf to California, and 0.3 maf to Nevada. Also quantifies tribal water

rights for specified tribes, including 131,400 af for diversion in California.

Colorado River Basin Project Act 1968 Requires Secretary of the Interior to prepare long-range operating criteria

for major Colorado River reservoirs.

U.S. Supreme Court Decree in 1979 Quantifies Colorado River mainstream present perfected rights in the

Arizona v. California, et al. Lower Basin states.

Hoover Dam and

Lake Mead. Lake Mead and

Lake Powell are the largest of

the Colorado River system

reservoirs.

Courtesy of USBR

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Within California, local agencies’ apportionments

of Colorado River water were established under the

Seven Party Agreement (Table 9-17), which has been

incorporated into water delivery contracts which the

Secretary of the Interior has executed with California

water users. Uses occurring within a state are charged

to that state’s allocation. Thus, federal water uses or

uses associated with federal reserved rights (e.g., tribal

water rights) must also be accommodated within

California’s basic apportionment of 4.4 maf/yr plus

one-half of any available surplus water.

The major local agencies in California using Colorado River water in the Colorado River Region are

TABLE 9-17

Annual Apportionment of Use of Colorado River Water

(all amounts represent consumptive use)

Interstate/International

Upper Basin States 7.5 maf

(Wyoming, Utah, Colorado, New Mexico, small portion of Arizona)

Lower Basin States 7.5 maf

(Arizona, Nevada, California)

Arizona 2.8 maf

Nevada 0.3 maf

California 4.4 maf

Republic of Mexicoa 1.5 maf

a Plus 200 taf of surplus water, when available. Water delivered to Mexico must meet specified salinity requirements.

Intrastate (Seven Party Agreement)b

Priority 1 Palo Verde Irrigation District (based on area of 104,500 acres).

Priority 2 Lands in California within USBR’s Yuma Project (not to exceed 25,000 acres).

Priority 3 Imperial Irrigation District and lands served from the All American Canal in Imperial and Coachella Valleys,

and Palo Verde Irrigation District for use on 16,000 acres in the Lower Palo Verde Mesa.

Priorities 1 through 3 collectively are not to exceed 3.85 maf/yr. There is no specified division of that amount among the

three priorities.

Priority 4 MWDSC for coastal plain of Southern California-550,000 af/yr.

Priority 5 An additional 550,000 af/yr to MWDSC, and 112,000 af/yr for the City and County of San Diegoc

.

Priority 6 Imperial Irrigation District and lands served from the All American Canal in Imperial and Coachella Valleys,

and Palo Verde Irrigation District for use on 16,000 acres in the Lower Palo Verde Mesa, for a total not to

exceed 300,000 af/yr.

Total of Priorities 1 through 6 is 5.362 maf/yr.

Priority 7 All remaining water available for use in California, for agricultural use in California’s Colorado River Basin.

b Indian tribes and miscellaneous present perfected right holders that are not identified in California’s Seven Party Agreement have the right to divert up to

 approximately 85 taf /yr (equating to about 50 taf/yr of consumptive use) within California’s 4.4 maf basic apportionment. These users are presently

 consumptively using approximately 32 taf/yr (assuming about 25 taf/yr of unmeasured return flow).

c

 Subsequent to execution of the Seven Party Agreement, San Diego executed a separate agreement transferring its apportionment to MWDSC.

PVID, BWD, IID, and CVWD. The Reservation

Division of USBR’s Yuma Project provides water to

Colorado River Indian tribes in California. The remainder of California’s Colorado River water use occurs

in the South Coast Region (Chapter 7). Figure 9-5 is a

plot of Lower Basin states’ apportionments compared

with historical Colorado River water use. As shown in

the figure, California’s use has historically exceeded its

basic apportionment, because California has been allowed to divert Arizona’s and Nevada’s unused

apportionments, and to divert surplus water. With

completion of the Central Arizona Project and the

1996 enactment of a state groundwater banking act,

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9-31 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

Arizona used more than its basic apportionment in

1997. Reduction of California’s Colorado River use

from current levels to 4.4 maf annually (when surplus

water is not available) has significant water management implications for the South Coast Region. In

calendar year 1996, actual consumptive use of the

Lower Basin states (without considering USBR’s unmeasured return flow credit of 239 taf) was:

Nevada 241 taf

Arizona 2,813 taf

California 5,256 taf

Total Lower Basin 8,310 taf

Within the Colorado River Region, IID, BWD,

and PVID receive virtually all of their supplies from

the Colorado River. IID and CVWD’s Colorado River

supplies are diverted into USBR’s All American Canal

at Imperial Dam; CVWD is served from the Coachella

Branch of the AAC. PVID diverts via the Palo Verde

Canal from the Colorado River near Blythe. BWD

receives its supplies from facilities of USBR’s Yuma

Project, which serves lands in both California and Arizona.

The interstate allocations provided in the 1922

Compact were made after a period of relatively wet

hydrology on the Colorado River. Some have suggested

that the allocations overstate the river’s normally availTABLE 9-18

Estimated Colorado River Flow and Usesa

maf

Average Flow (1906-95)

Upper Basin 15.1

Lower Basin 1.4

Total 16.5

Current Uses

Upper Basin 3.8

Lower Basin (mainstem)b 7.5

Mexico 1.5

Mainstem Evaporation and Losses 1.9

Total 14.7

Average Flow into Reservoir

Storage (16.5 - 14.7) 1.8

a

 Prepared by the CRB.

b Reflects restriction on MWDSC’s diversion as Central Arizona

 Project and Southern Nevada Water System increase diversions to

 Arizona’s and Nevada’s basic apportionments.

able water supply, even without consideration of subsequent calls on that water supply for tribal water rights

and endangered species fishery water needs. Table 9-

18 provides an overview of average river hydrology.

While consumptive use from the mainstem in the

Lower Basin is assumed to be its basic apportionment

of 7.5 maf, Upper Basin use is still well below its Colorado River Compact apportionment. Current

Basic Apportionment and Consumptive Use of

Mainstem Colorado River in Lower Basin

FIGURE 9-5

V o l u m e i n m a f

California Use

Arizona Use

Nevada Use

California Basic

Apportionment

Arizona Basic

Apportionment

Nevada Basic

Apportionment

1970

0

1

2

3

4

5

6

1975 1980 1985 1990 1995

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USBR’s Imperial Dam on

the Colorado River. The

structures in the foreground

are a series of desilting basins

used to reduce the sediment

load of river water before it

enters the All American

Canal.

Courtesy of USBR

TABLE 9-19

SWP Contractors in the Colorado River Region

Maximum Annual

Agency Contract Entitlement (taf) SWP Deliveries in 1995 (taf)

Coachella Valley WD 23.1 23.1

Desert Water Agency 38.1 38.1

Mojave Water Agencya 75.8 8.7

San Gorgonio Pass Water Agency 17.3 0

a

 Contract entitlement covers both South Lahontan and Colorado River Regions; 7.3 taf of this amount is allocated to Colorado River Region.

projections are that the Upper Basin will not reach its

full Compact apportionment until after 2060.

Supplies from Other Sources

Local agencies contracting with the SWP for part

of their supplies are shown in Table 9-19.

Neither CVWD nor DWA have facilities to take

direct delivery of SWP water. Instead, both agencies

have entered into exchange agreements with MWDSC,

whereby MWDSC releases water from its Colorado

River Aqueduct into the Whitewater River for storage

in the upper Coachella Valley groundwater basin. In

turn, MWDSC takes delivery of an equal amount of

the agencies’ SWP water. San Gorgonio Pass Water

Agency, which serves the Banning/Beaumont area, also

lacks the facilities to take delivery of SWP water, and

to date has received no actual supply from the SWP.

SGPWA will receive SWP supply when the Department completes its extension of the East Branch of the

California Aqueduct in 2000.

Groundwater, local surface water, and water recycling provide the remaining supplies for this region.

CVWD, working with DWA, has an active groundwater recharge program for the upper end of the

Coachella Valley (generally, the urbanized part of the

valley). CVWD recharges groundwater with imported

Colorado River supplies and with Whitewater River

flows using percolation ponds constructed in the

Windy Point area. CVWD and DWA levy extraction

fees on larger groundwater users in the upper Coachella

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9-33 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

Valley. Imperial Valley, the largest water-using area in

the region, does not have significant supplies of usable

groundwater.

Local Water Resources

Management Issues

Management of California’s

Colorado River Water

The major water management issue in this region

is California’s use of Colorado River water in excess of

its basic annual apportionment of 4.4 maf. In the past,

Arizona and Nevada were not using the full amount

of their basic apportionments, and in accordance with

the law of the river, California was able to use the

amount apportioned to, but not used by, Nevada and

Arizona. Discussions among the seven basin states and

ten Colorado River Indian Tribes over changes to Colorado River operating criteria and ways for California

to reduce its Colorado River water use began as early

as 1991. The drought in Northern California prompted

California to request that USBR make surplus water

available, so that maximum use could be made of Colorado River water in Southern California. These

discussions over changes to reservoir operations and how

surplus or shortage conditions could be established continued for a time in a forum known as the “7/10 process.”

More recently, the California local agencies, working through the Colorado River Board of California,

have been developing a proposal for discussion with

the other basin states to illustrate how, over time, California would reduce its use to the basic apportionment

of 4.4 maf/yr. Drafts of the proposal, known as the

Colorado River Board draft 4.4 Plan, have been shared

with the other states. Efforts are being made to reach

intrastate consensus on the plan in 1998. As Bulletin

160-98 goes to press, the most current version of the

draft plan is the December 1997 version. The following text is based on that version.

As currently formulated, the draft plan would be

implemented in two phases. The first phase (between

the present and 2010 or 2015) would entail implementing already identified measures (such as water

conservation and transfers) to reduce California’s Colorado River water use to about 4.6 to 4.7 maf/yr. The

second phase would implement additional measures

to reduce California’s use to its basic annual 4.4 maf

apportionment in those years when neither surplus

water nor other states’ unused apportionments was

available. One of the fundamental assumptions made

in the plan is that MWDSC’s Colorado River Aqueduct will be kept full, by making water transfers from

agricultural users in the Colorado River Region to urban water users in the South Coast Region. (The

Colorado River Aqueduct’s capacity is a maximum of

Imperial Irrigation District,

formed in 1911, acquired

conveyance facilities

constructed by a bankrupt

privately owned irrigation

company. In 1918, IID

constructed Rockwood

Heading (shown here) on the

original canal system.

Keeping the canal system

from being choked by the

Colorado River’s high

sediment loading was

difficult; note the dredge

shown in the background.

These early facilities were

subsequently replaced by

the All American Canal.

Courtesy of Imperial Irrigation District.

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1.3 maf/yr. However, as shown in Table 9-17,

MWDSC has a fourth priority right to only 550 taf

annually—the remaining capacity of the aqueduct has

historically been filled with unused apportionment

water of other entities or with water from hydrologic

surpluses.)

In the December 1997 draft plan, specific actions

were included in the first phase: core water transfers

(every year water transfers) such as the existing IID/

MWDSC agreement and the proposed IID/SDCWA

transfer; seepage recovery from unlined sections of the

All American and Coachella Canals; drought year water transfers similar to the PVID/MWDSC pilot

project; groundwater banking in Arizona; and conjunctive use of groundwater in areas such as the Coachella

Valley. The actions are described in more detail below.

The draft plan recognizes that transfers of conserved

water must be evaluated in the context of preserving

the Salton Sea’s environmental resources, and also that

plan elements must address environmental impacts on

the lower Colorado River and its listed species.

Other actions to occur as part of the first phase

would include implementation of the San Luis Rey

Indian water rights settlement authorized in PL 100-

675 and implementation of measures to administer

agricultural water entitlements within the first three

priorities of the Seven Party Agreement. Examples of

such measures include quantifying amounts of water

conserved or transferred, and annually reconciling water

use with water allocations (e.g., overrun accounting).

An important element of the CRB draft 4.4 plan

is the concept that existing reservoir operating criteria

be changed by USBR to make optimum use of the

river’s runoff and available basin storage capacity. California agencies developed new proposed operating

criteria that are included in the draft plan. The draft

plan contemplates that changes in operating criteria

would be part of both the first and second phases. The

other basin states have been cautious in their reaction

to California’s proposals for reservoir reoperation, and

have suggested, for example, that new criteria should

not be implemented until California has prepared the

environmental documents and executed the agreements

that would be needed to begin implementation of the

plan. (In its 1995 five-year review of Colorado River

operating criteria, USBR had announced that it

planned no changes to existing criteria.)

The second phase of the CRB draft 4.4 plan would

include additional average year and drought year water transfers. Specifics on these transfers would be

developed during the first phase of plan implementation. One suggested component is construction of

desalting facilities on rivers tributary to the sea, to divert and treat agricultural drainage water that would

otherwise enter the sea. The treated water could be

conveyed to urban water users in the South Coast Region via the Colorado River Aqueduct. As with any

alternative that would reduce the amount of relatively

fresh water reaching the sea, the environmental impacts of this approach would require careful evaluation.

Other components of the second phase would include

further transfers of conserved agricultural water to the

USBR’s Parker Dam on the

Colorado River impounds

Lake Havasu. At this

location, the Colorado River

forms the stateline between

California and Arizona.

MWDSC’s Colorado River

Aqueduct and the Central

Arizona Project divert from

Lake Havasu.

New Parker Dam photo

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9-35 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

South Coast and further work on reservoir operating

criteria. Implementation of some elements of phase

two of the plan may extend beyond the Bulletin 160-

98 planning horizon.

Tribal Water Rights

Colorado River Indian Tribes. As a result of the

1964 U.S. Supreme Court decree in Arizona v. California, California’s basic apportionment of Colorado

River water was quantified and five lower Colorado

River Indian Tribes were awarded 905 taf of annual

diversions, 131 taf of which were allocated for diversion in and chargeable to California pursuant to a later

supplemental decree.

In 1978, the tribes asked the court to grant them

additional water rights, alleging that the U.S. failed to

claim a sufficient amount of irrigable acreage, called

omitted lands, in the earlier litigation. The tribes also

raised claims called boundary land claims for more

water based on allegedly larger reservation boundaries

than had been assumed by the court in its initial award.

In 1982, the special master appointed by the Supreme

Court to hear these claims recommended that additional water rights be granted to the Indian tribes. In

1983, however, the Supreme Court rejected the claims

for omitted lands from further consideration and ruled

that the claims for boundary lands could not be resolved until disputed boundaries were finally

determined. Three of the five tribes—Fort Mojave

Indian Tribe, Quechan Indian Tribe, and Colorado

River Indian Tribe—are pursuing additional water

rights related to the boundary lands claims. A settlement has been reached on the Fort Mojave claim and

may soon be reached on the CRIT claim. Both settlements would then be presented to the special master.

The Quechan claim has been rejected by the special

master on the grounds that any such claim was necessarily disposed of as part of a Court of Claims

settlement entered into by the tribe in a related matter

in the mid-1980s. As with all claims to water from the

mainstem of the Colorado River and any determination by the special master, only the U.S. Supreme Court

itself can make the final ruling.

If both the Fort Mojave and CRIT settlements

were approved, the tribes would receive water rights

in addition to the amounts granted them in the 1964

decree.

San Luis Rey Indian Water Rights Settlement

Act. The San Luis Rey Indian Water Rights Settlement

Act (Public Law No. 100-675; 102 Stat. 4000 [1988])

is to provide for the settlement of the reserved water

rights claims of the La Jolla, Rincon, San Pasqual,

Pauma, and Pala Bands of Mission Indians. Litigation

(affecting the interests of the United States, the City

of Escondido, the Escondido Mutual Water Company,

the Vista Irrigation District, and the Bands) and proceedings before the Federal Energy Regulatory

Commission involved tribal water rights claims to the

waters of the San Luis Rey River and questions about

the validity of rights-of-way granted by the U.S. across

tribal and allotted lands. The act authorizes and directs the Secretary of the Interior to arrange for a 16 taf/

yr supplemental supply of water to benefit the Bands

and the local communities. This supply can be obtained either from water development from public

lands in California outside the service area of the CVP,

from water salvaged as the result of lining part of the

AAC or Coachella Canal, or through a contract with

MWDSC. Title II of PL 100-675 authorized the Secretary of the Interior to line parts of the canals, and

permitted the Secretary to enter into an agreement or

agreements with PVID, IID, CVWD, and/or

MWDSC for the construction or funding. The act did

not authorize appropriation of federal funds for canal

lining.

Water Conservation Programs

There have been several large-scale water conservation actions involving Colorado River water users,

as shown in Table 9-20.

Salton Sea

The present day Salton Sea was formed in 1905,

when Colorado River water flowed through a break in

a canal that had been constructed along the U.S./Mexican border to divert the river’s flow to agricultural lands

Colorado River Board of California

The Colorado River Board of California is the State

agency responsible for administering California’s

Colorado River water allocation, and for dealing with

the other basin states on river management issues. The

Board is composed of six members representing the

California agencies who were signatories to the 1931

Seven-Party Agreement, two public members, and two

ex-officio members (the directors of the Department and

DFG). The six local agencies represented on the CRB

are CVWD, IID, LADWP, MWDSC, PVID, and

SDCWA. CRB’s office and staff are located in Glendale.

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in the Imperial Valley. Until that break was repaired in

1907, the full flow of the river was diverted into the

Salton Sink, a structural trough whose lowest point is

about 278 feet below sea level. Within geologic time,

the Colorado River’s course has altered several times.

At times, the river discharged to the Gulf of California

as it does today. At other times it flowed into the Salton

Sink. Lake Cahuilla, the most recent of several prehistoric lakes to have occupied the Salton Sink, dried up

some 300 years ago.

Over the long term, the sea’s elevation has gradually

increased, going from a low on the order of -250 feet

in the 1920s to its present level of about -226 feet.

The sea’s maximum elevation in recent years was -225.6

in 1995. Since some shoreline areas are relatively flat,

a small change in elevation can result in a large difference in the extent of shoreline submerged. Levees have

been constructed to protect adjacent farmland and

structures at some sites along the shoreline; the remaining managed acreage of the Salton Sea National

Wildlife Refuge is also protected from the sea by levees.

The Salton Sea is the largest lake located entirely

within California, with a volume of about 7.5 maf at

its present elevation of -226 feet. The sea occupies a

closed drainage basin—if there were no inflows to

maintain lake levels, its waters would evaporate as did

those of prehistoric Lake Cahuilla. The area’s average

annual precipitation is 3 inches or less, while average

annual evaporation is in excess of 5 feet. The sea receives over 1 maf of inflow annually, primarily from

TABLE 9-20

Existing Colorado River Region Water Conservation Actions

Year Action Participants Comments/Status Estimated Savings

1980 Line 49 miles of USBR, Project completed. 132 taf/yr

Coachella Branch CVWD,

of All American MWDSC

Canal

1988 IID distribution IID, MWDSC Multi-year agreement, extends 107 taf/yr in 1998

system into 2033. Projects MWDSC has

improvements funded include canal lining,

and on-farm regulatory reservoir and spill

water interceptor canal construction,

management tailwater return systems, nonactions leak gates, 12-hour delivery of

water, drip irrigation systems,

linear-move irrigation systems,

and system automation.

MWDSC has funded over

$150 million for conservation

program costs through 1997.

1992 Groundwater MWDSC, Test program to bank up to MWDSC and SNWA have

banking in CAWCD, 300 taf. stored 139 taf in Arizona

Arizona SNWA groundwater basins.

1992 PVID land PVID, Project completed. Two-year Total of 186 taf was

fallowing MWDSC land fallowing test program. made available from the

Covered 20,215 acres in PVID. program, although the water

MWDSC paid $25 million to was subsequently released

farmers over a two-year period. from Lake Mead when

flood control releases were

made from the reservoir.

1995 Partnership USBR, Provides, among other things, N/A

agreement CVWD for studies to optimize reasonable

beneficial use of water in the

district.

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9-37 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

agricultural drainage. The largest sources of inflow

(about 80 percent of the total) are the New and Alamo

Rivers which drain agricultural lands in the Mexicali

and Imperial Valleys and flow into the sea’s southern

end. The New River also receives untreated and minimally treated wastewater flows from the Mexicali area;

monitoring results generally indicate that pollution associated with wastewater discharges does not reach the

sea because of its distance from the Mexican border.

In 1924, President Coolidge issued an executive

order withdrawing seabed lands lying below elevation

-244 feet for the purpose of receiving agricultural drainage water. That order was expanded in 1928 to lands

below elevation -220 feet. The sea supports water-based

recreational activities, and has had a popular corvina

fishery. During the 1950s, the highest per capita sport

fishing catches in California were from the Salton Sea.

Over the years, concerns about the sea’s salinity have

been voiced in the context of maintaining the recreational fishery that was established with introduced

species able to tolerate high salinities.

The sea also provides important wintering habitat

for many species of migratory waterfowl and shorebirds, including some species whose diets are based

exclusively on the fish in the sea. Wetlands near the

sea and adjoining cultivated agricultural lands offer the

avian population a mix of habitat types and food sources. An area at the sea’s south end was established as a

national wildlife refuge in 1930, although most of that

area is now under water as a result of the sea’s rising

elevation. Some of the 380 bird species wintering in

the area include pelicans, herons, egrets, cranes, cormorants, ibises, ducks, grebes, falcons, plovers, avocets,

sandpipers, and gulls. The Salton Sea is considered to

be a major stopover point for birds migrating on the

Pacific Flyway, and has one of the highest levels of bird

diversity of refuges in the federal system.

Historically, salinity has been the water quality

constituent of most concern at the sea. Present levels

are about 44,000 mg/L TDS (seawater is about

35,000 mg/L TDS). This high level of salinity reflects

long- term evaporation and concentration of salts

found in its inflow. Selenium has been a more recent

constituent of interest, due to its implications for

A false-color infrared satellite

photo of the Salton Sea

(January 1998 Landsat 5).

The irrigated areas in

Imperial Valley are clearly

visible to the south of the sea,

as are the Algodones Dunes

to the southeast. The City

of Mexicali and irrigated

acreage in the Mexicali

Valley can also be seen.

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-38

aquatic species. Although selenium levels in the water

column in the sea are less than the federal criterion of

5ug/L, this concentration can be exceeded in seabed

sediment and in influent agricultural drainage water.

Agricultural drain flows also contribute significant

nutrient loading to the sea, which supports large algal

blooms at some times of the year. These algal blooms

have contributed to odor problems and low dissolved

oxygen levels in some areas of the sea.

Over the years, USBR and others have considered

potential solutions to stabilize the sea’s salinity and elevation. Most recently, the Salton Sea Authority (a joint

powers authority consisting of Riverside and Imperial

Counties, IID, and CVWD) and others have been

performing appraisal level evaluations of some of the

frequently suggested alternatives. Categories of alternatives considered include:

• Diking off part(s) of the sea to create evaporation

pond(s) adjoining the primary water body. This

approach would divert part of the sea’s water into

managed impoundments, where the water would

be concentrated into a brine and the salts would

eventually be removed. The facilities would be

sized to maintain a primary waterbody at some

desired salinity concentration and elevation. The

desired salinity concentration would probably be

near that of ocean water (or slightly greater) to

maintain the recreational fishery.

• Pumping Salton Sea water and exporting it to some

other location. Possible discharge locations include

nearby dry desert lakebeds (to create evaporation

ponds), evaporation ponds to be constructed near

the sea, the Gulf of California, or the Laguna

Salada in Mexico.

• Building treatment facilities (such as a desalting

plant) to remove salts from inflows to the sea.

• Importing fresh water to the sea. The most apparent source would be the Colorado River, but only

in years when flood control releases were being

made in excess of U.S. needs.

Maintaining a viable Salton Sea has several water

management implications. First will be the actions

needed to stabilize the sea’s salinity in the near-term,

such as the Authority’s diking proposal. Eventually, a

long-term solution will need to be developed. A wide

range of costs has been mentioned for a long-term solution, including amounts in the billion-dollar range.

Some of the possible long-term solutions suggested

would entail constructing facilities in Mexico, bringing a greater level of complexity to their

implementation. Other water management programs

in the region, such as proposals to transfer conserved

agricultural water supplies, will have to be evaluated

in terms of their impacts on the sea. Recent proposals

to desalt water in the Alamo or New Rivers and to

transport that water in the Colorado River Aqueduct

to the South Coast for urban water supply have raised

concerns about maintaining the sea’s environmental

productivity. Such proposals might be implemented

as part of the second phase of CRB’s draft 4.4 Plan.

(In 1997, CVWD filed an application with the

SWRCB for water rights to storm water flows and

drainage flows in the Whitewater River at the sea’s

northern end. MWDSC made a similar filing for agricultural drainage flowing into the sea’s southern end.)

Congressional legislation introduced in 1998

would authorize expenditure of federal funds for a

multi-year study of the sea’s resources and potential

solutions for managing its salinity.

Coachella Valley Groundwater Overdraft

Most PSAs within the Colorado River Region have

sufficient water to meet future water needs, with the

exception of Coachella Valley. Groundwater overdraft

is occurring in the upper (urbanized) part of the valley; DWA and CVWD have been managing extractions

in that basin to minimize future overdraft. Imported

surface water at the upper end of the valley has provided a source of recharge water.

Groundwater overdraft is also occurring in the

Roadrunners are one of the bird species found year-round in

the Salton Sea area.

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9-39 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

lower (agricultural) portion of the valley, an area that

roughly coincides with CVWD’s Improvement District No.1. CVWD estimates that actual 1995 water

use within the district was about 520 taf, part of which

was supplied by overdrafting the groundwater basin.

(Irrigators in the lower valley are supplied by surface

water from the Coachella Canal and by groundwater.)

The district is in the process of preparing a groundwater management plan for the lower valley, and has

considered alternatives including basin adjudication,

water conservation, water recycling, and direct or in

lieu recharge with water imported from the Colorado

River or from the SWP. CVWD estimates that overdraft in the lower valley is about 170 taf/yr. Overdraft

calculated from Bulletin 160-98 water budgets is 70

taf/yr for the upper and lower valley combined.

Lower Colorado River

Environmental Water Issues

Listed fish species on the mainstem of the Colorado River include the Colorado squawfish, razorback

sucker, humpback chub, and bonytail chub. Restoration actions to protect these fish may affect reservoir

operation and streamflow in the mainstem and tributaries. Other species of concern in the basin include

the bald eagle, Yuma clapper rail, belted kingfisher,

southwestern willow flycatcher, and Kanab ambersnail.

In 1993, USFWS published a draft recovery implementation plan for endangered fish in the upper

Colorado River Basin. The draft plan included protecting instream flows, restoring habitat, reducing

impacts of introduced fish and sportsfish management,

conserving genetic integrity, monitoring habitat and

populations, and increasing public awareness of the

role and importance of native fish.

Problems facing native fish in the mainstem Colorado River and its tributaries will not be easily resolved.

For example, two fish species in most danger of extinction, the bonytail chub and razorback sucker, are

not expected to survive in the wild. Although there

was a commercial razorback fishery until 1950, in recent years most stream and reservoir fisheries in the

basin have been managed for non-native fish. These

management practices have harmed residual populations of natives. Many native fish are readily propagated

in hatcheries, and thus recovery programs include captive broodstock programs to maintain the species.

Reestablishing wild populations from hatchery stocks

will have to be managed in concert with programs to

manage river habitat. For example, although 15 million juvenile razorback suckers were planted in Arizona

streams from 1981-90, the majority of these planted

fish were likely eaten by introduced predators. In 1994,

the states of Colorado, Wyoming, and Utah reached

an agreement with USFWS on protocols for stocking

non-native fish in the Upper Basin—stocking protocols consistent with native fish recovery efforts. In a

program which began in 1989, USBR and other state

and federal agencies have cooperated to capture, rear,

and successfully reintroduce about 15,000 razorback

sucker larvae in Lake Mojave.

Instream flows in the mainstem and key tributaries are being evaluated as components of native fish

recovery efforts. State and federal agencies are conducting studies to estimate base flow and flushing flow

needs for listed and sensitive species in various river

Groundwater recharge ponds

at Windy Point, to the east

of San Gorgonio Pass in

Riverside County. Water

from the Whitewater River,

along with Colorado River

Aqueduct supplies exchanged

for SWP deliveries of

CVWD and DWA, provides

recharge in the upper

Coachella Valley area.

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-40

reaches. An example of flushing flow evaluation occurred in the spring of 1996 when releases from Glen

Canyon Dam were increased for several days to attempt to redistribute sediment and create shallow water

habitat in the mainstem below the dam.

In a 1997 court action involving the southwestern willow flycatcher, an environmental group filed a

lawsuit against USBR and USFWS under the ESA’s

citizen suit provisions. The group alleged that USBR’s

operation of Lake Mead was endangering the

flycatcher’s habitat at the upper end of Lake Mead.

The federal district court for Arizona ruled in favor of

USBR, but the environmental group appealed the district court’s decision to the Ninth Circuit Court of

Appeals. The appellate court subsequently declined to

hear the case, letting the district court’s decision stand.

Lower Colorado River

Multi-Species Conservation Program

In 1995, DOI executed partnership agreements

with California, Nevada, and Arizona to develop a

multi-species conservation program for ESA-listed species and many non-listed, but sensitive, species within

the 100-year floodplain of the lower Colorado River,

from Glen Canyon Dam downstream to the Mexican

border. In 1996, a joint participation agreement was

executed to provide funding for the program. USFWS

has designated the LCRMSCP steering committee as

an ecosystem conservation and recovery implementation team pursuant to ESA. The steering committee is

composed of representatives from the three states, DOI,

Indian tribes, water agencies, power agencies, environmental organizations, and others.

The conservation program will work toward recovery of listed and sensitive species while providing

for current and future use of Colorado River water

and power resources, and includes USBR’s Colorado

River operations and maintenance actions for the lower

river. Over 100 species will be considered in the program, including the southwestern willow flycatcher,

Yuma clapper rail, and the four listed fish species mentioned above. Developing the program is estimated to

take three years. Costs of program development and

implementation of selected interim conservation measures, estimated at $4.5 million, are to be equally split

between DOI and the nonfederal partners.

USBR initiated a formal Section 7 consultation

process with USFWS, who issued a five-year biological opinion on USBR operation and maintenance

activities from Lake Mead to the southerly international boundary with Mexico in 1997. USBR has

estimated that the cost of implementing the biological

opinion’s reasonable and prudent alternatives and measures could be as high as $26 million.

The steering committee is currently participating

in funding several interim conservation measures.

These include a razorback sucker recovery program at

Lake Mojave, restoration of Deer Island near Parker,

Arizona, and a “Bring Back the Natives” program sponsored by the National Fish and Wildlife Foundation.

Water Management Options

for the Colorado River Region

The only forecasted shortages within the Colorado River region are those resulting from groundwater

overdraft in Coachella Valley. Implementing the draft

CRB 4.4 Plan entails developing options in the Colorado River Region to keep MWDSC’s Colorado River

Aqueduct flowing at its full capacity, as described

earlier. The reduction in California’s use of Colorado

River water to the basic 4.4 maf apportionment reduces the supply available to California by as much as

0.9 maf/yr.

Table 9-21 shows a list of options for the region,

and the results of an initial screening of the options.

The retained options were evaluated (Table 9A-3 in

Appendix 9A) based on a set of fixed criteria discussed

in Chapter 6. These options could be used for implementing the draft CRB 4.4 Plan and for reducing the

Colorado River Region’s groundwater overdraft.

Water Conservation

Urban. Urban water demand forecasts for 2020

assume that BMPs are in place; consequently, only

those urban conservation efforts which exceed BMPs

are considered as options. All urban conservation options were retained. Reducing outdoor water use to

0.8 ETo in new development would attain 9 taf/yr of

depletion reductions, while extending this measure to

include existing development would reduce depletions

by 18 taf/yr. Reducing indoor water use to 60 gpcd

and 55 gpcd would reduce depletions by 2 and 3 taf/

yr, respectively. Reducing commercial, institutional,

and industrial water use by 3 percent and 5 percent

would save 1 and 2 taf/yr, respectively. Reducing distribution system losses to 7 and 5 percent would result

in 9 and 13 taf/yr of depletion reductions, respectively.

Agricultural. The 2020 agricultural water demand

forecasts assume that EWMPs are in place. As with

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9-41 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

TABLE 9-21

Colorado River Region List of Water Management Options

Option Retain Reason for Deferral

or Defer

Conservation

Urban

Outdoor Water Use to 0.8ETo Retain

Indoor Water Use Retain

Interior CII Water Use Retain

Distribution System Losses Retain

Agricultural

Seasonal Application Efficiency Improvements Retain

Flexible Water Delivery Retain

Canal Lining and Piping Retain

Tailwater Recovery Retain

Modify Existing Reservoirs/Operations

Reoperating Colorado River System Reservoirs Defer Concurrence of USBR and other basin states not

yet obtained.

New Reservoirs/Conveyance Facilities

Additional Conveyance Capacity for Colorado Defer California’s current excess use of Colorado River

River Water water.

Groundwater/Conjunctive Use

Groundwater Recharge Project at East Mesa Defer Scoped as one-time program.

Water Marketing

Interstate banking Retain

Intrastate banking and transfers Retain

Land fallowing program Retain

Water Recycling

Water recycling options Defer Water recycling options would not generate new

water supply.

Desalting

Brackish Groundwater

— ——

Seawater

— ——

Other Local Options

Desalting local drainage water Defer To be evaluated in phase 2 of draft CRB 4.4 Plan.

Lining All American Canal Retain

Additional Lining of Coachella Canal Retain

Weather Modification Defer Complicated by interstate management issues.

Statewide Options

— — See Chapter 6.

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-42

the urban water management options, only those agricultural conservation efforts which exceed EWMPs

are considered as options. Improving seasonal application efficiency to 80 percent from the base of

73 percent could reduce depletions by 50 taf/yr. Improving flexible water delivery, canal lining (on-farm

and distribution system), and tailwater recovery systems could together realize 140 taf/yr in depletion

reductions. However, the ability to implement conservation options that would reduce the amount of

fresh water inflow to the Salton Sea must be evaluated

on a project-specific basis. Goals for preservation of

the sea’s environmental resources may limit the extent

of feasible conservation measures.

Land Fallowing. Programs such as the Palo Verde

test land fallowing program could be implemented to

provide water for transfer to urban areas in the South

Coast Region during drought periods. In 1992,

MWDSC conducted a two-year land fallowing test

program with PVID. Under this program, growers in

PVID fallowed about 20,000 acres of land. The saved

water, about 93 taf/yr, was stored in Lower Colorado

River reservoirs for future use by MWDSC (the water

was later released when Colorado River flood control

releases were made from Lake Mead). MWDSC paid

each grower $1,240 per fallowed acre, making the cost

of the water to MWDSC about $135/af. Similar programs could be implemented in the future to provide

about 100 taf/yr during drought years. Future land

fallowing agreements would need to consider the availability of storage for the transferred water.

Potential Sources of

Water for Intrastate Marketing

The ability to market conserved water has already

been demonstrated in the region. Table 9-22 summarizes some potential sources of water for intrastate

transfers. Such transfers could make up some of the

shortages in the South Coast Region resulting from

California reducing its use to California’s basic apportionment of 4.4 maf.

Construction of additional conveyance capacity

from the Colorado River Region to the South Coast

Region has been a recent subject of discussion. Proposition 204 provides funding for a feasibility study of a

new conveyance facility from the Colorado River to

the South Coast Region. Conveyance facilities mentioned include a new aqueduct from the Imperial Valley

area to San Diego (on the United States side of the

border), as well as San Diego’s participation in enlarging the existing aqueduct serving Tijuana, Mexico.

Tijuana’s situation is similar to San Diego’s, in that

Tijuana is seeking to expand its urban supplies by negotiating transfer of agricultural water from the

Mexicali Valley. Figure 9-6 is a map of the U.S. - Mexican border area, showing the area’s larger water facilities.

A preliminary engineering study of constructing a new

canal from Imperial Valley to SDCWA’s service area

has been prepared for SDCWA. Additional work, including geotechnical exploration and environmental

studies, would be needed to evaluate the project’s feasibility. The preliminary study highlighted the need to

evaluate desalting the water that the aqueduct would

supply, to enable San Diego’s continued reliance on a

high level of water recycling. New conveyance facilities from the Colorado River Region to the South Coast

Region have been deferred from evaluation in Bulletin 160-98 because it does not appear that they would

be constructed within the Bulletin’s planning horizon,

given the other basin states’ concerns about California’s

TABLE 9-22

Potential Colorado River Water Conservation Programs

Program Participants Comments/Status Estimated Savings

Lining of All USBR, IID Authorized by PL 100-675. Final EIS/EIR Not implemented yet.

American Canal CVWD, MWDSC published. Preferred alternative is constructing Potential of 67.7 taf/yr

a new, lined parallel canal. savings.

Agreement for a IID, SDCWA SCDWA and IID executed an agreement in Not implemented yet -

long-term transfer 1998. Initial agreement negotiated for wheeling up to 200 taf/yr savings.

of up to 200 taf/yr water in MWDSC’s Colorado Aqueduct.

EIR/EIS not yet prepared.

Additional lining USBR, others Authorized by PL 100-675. Draft EIR/EIS Not implemented yet.

of Coachella Canal issued. Potential of 25.68 taf/yr

savings.

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9-43 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

FIGURE 9-6

U.S.-Mexican Border Region

All American

Colorado

River

Imperial

Beach

El Centro

Alamo

River

New

River

Canal

Calexico

Coachella

River

Imperial

Dam

Laguna

Dam

Colorado

River

San

Luis Rey San

River

Diego

San Vicente

Reservoir Aqueducts

Lower Otay

Reservoir

San Diego

Gila

Salton

Sea

Senator

Wash

Dam

AR IZONA

ORN IA CAL IF

CAL IFORN IA

P

a

c

i f i

c

O

c

e

a

n

Gulf

of

California

Rodriguez

Reservoir

Tecate

Rio de

las

Palmas

Ensenada

Rio

San Carlos

Rio Santo Tomas

Rio

San

Antonio

San Luis

Mexicali

Morelos

Dam

Yuma

Tijuana

Canal

Alamo

Laguna

Salada

River

El Carrizo

Reservoir

Rio Colorado -

Tijuana Aqueduct

Cienega de 

Santa Clara

River

Tiju

MEX ICO

MEX ICO

AR IZONA

Aqueduct

Canal

ana

Colorado

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OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-44

use of Colorado River water and the international complexities associated with a joint project with Mexican

agencies.

SDCWA and IID have been negotiating a potential transfer of water saved due to extraordinary

conservation measures within IID. The agencies initially executed a 1995 MOU concerning negotiation

of a transfer agreement, followed by 1998 execution

of an agreement specifying the transfer’s terms and conditions. The agreement has a minimum 45-year term,

and can be extended for an additional 30 years. An

initial transfer of 20 taf would begin in 1999, with the

annual quantity of transferred water increasing to a

maximum of 200 taf. In order to transfer the acquired

water, SDCWA (a member agency of MWDSC) has

negotiated an initial wheeling agreement with

MWDSC for use of capacity in MWDSC’s Colorado

River Aqueduct. Environmental documentation for the

transfer is pending.

Past conservation projects in the region have included land fallowing, canal lining, distribution system

reservoir and spill interceptor canal construction, and

irrigation distribution system improvements. Some

proposed projects to recover canal seepage include:

• Lining part of the All American Canal. Public

Law 100-675 authorized the Secretary of the Interior to line the canal or to otherwise recover canal

seepage, using construction funds from PVID,

IID, CVWD, or MWDSC. USBR’s environmental documentation evaluated a parallel canal

alternative, several in-place lining alternatives, and

a well field alternative, and concluded that the preferred alternative was the construction of a

concrete-lined canal parallel to 23 miles of the existing canal. The parallel canal alternative has the

potential to conserve an estimated 67.7 taf annually of Colorado River water. Recently, the well

field alternative has been reevaluated and found

to be infeasible. The well field alternative, although

less expensive than canal lining, has been set aside

because of international concerns about groundwater extraction near the border.

• Lining the Remaining Section of the Coachella

Canal. This project would involve lining the remaining 33.4 miles of the Coachella Canal, which loses

about 32.4 taf/yr through seepage. Four alternatives

that have been identified are conventional lining,

underwater lining, parallel canal, and no action. It is

estimated that the preferred alternative, conventional

lining, would conserve 25.7 taf/yr.

Intrastate Groundwater Recharge or Banking

IID has proposed a groundwater recharge project

at East Mesa in the Imperial Valley. The proposed recharge project would divert a portion of flood control

releases from Lake Mead to a recharge site or sites located along the alignment of the old, unlined Coachella

Canal. (The old canal was abandoned when an adjacent lined canal was constructed.) IID estimates that

up to 20 taf could be recharged in 1998. IID prepared

a mitigated negative declaration for a one-time program in 1998, when flood control releases are

occurring. Since Colorado River flood control releases

have historically been infrequent, future water supply

for such a recharge program would be available only

occasionally. This option was scoped as a one-time

project and is not considered as a 2020-level option in

Bulletin 160-98.

MWDSC has executed agreements with three entities to study the potential of groundwater banking

arrangements that would involve storing surplus Colorado River water, when available, in groundwater basins

near its Colorado River Aqueduct. The water would

be withdrawn for use in the South Coast in drought

years. An agreement with Cadiz Land Company covered a potential project that would entail constructing

a 35-mile pipeline from the Cadiz Valley/Fenner Valley area, and diverting up to 100 taf/yr of surplus

Colorado River water to storage. Estimated available

groundwater storage capacity is 500 taf, with drought

year withdrawal capability of 100 taf. This arrangement could additionally have a marketing component;

perhaps 20 to 30 taf/yr of recharge in Cadiz and Fenner

Valleys could be blended with Colorado River water

and delivered to the South Coast Region. An agreement with Catellus Development Company covered a

potential groundwater storage site in the Mojave Desert

with an estimated capacity of 600 taf. The withdrawal

capability of this site is estimated at about 150 taf/yr.

A third agreement was with CVWD. CVWD is presently performing pilot studies to estimate recharge and

withdrawal capabilities in the lower valley. (MWDSC

and CVWD have already been evaluating increased

recharge at the upper end of the valley, in the

Whitewater River drainage basin.)

Technical studies of the feasibility of these projects

remain to be completed, and environmental documentation has not yet been prepared. It appears likely that

at least 100 taf/yr of drought year supplies could be

provided through this group of potential storage sites.

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9-45 OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS

Interstate Banking/Conservation

Under an existing agreement between MWDSC

and the Central Arizona Water Conservation District,

MWDSC can store a limited amount of Colorado

River water in Arizona for future use. The Southern

Nevada Water Authority is also participating in the

program. The agreement stipulates that MWDSC and

SNWA can store up to 300 taf in central Arizona

through the year 2000. As of 1997, MWDSC has

placed 89 taf in storage and SNWA has placed 50 taf

in storage, for a total of 139 taf. About 90 percent of

the stored water can be recovered, contingent upon

the declaration of a surplus. When MWDSC is able

to draw on this source, it can divert up to a maximum

of 15 taf in any one month. The stored water would

be made available by Arizona foregoing the use of part

of its normal supply from Central Arizona Project.

MWDSC plans to recover the stored water at times in

the future when its Colorado River Aqueduct diversions may be limited. Like the East Mesa project

described in the preceding section, this interstate

project was a one-time action, and is not considered as

a 2020-level option in Bulletin 160-98.

In its 1996 session, the Arizona Legislature enacted legislation establishing the Arizona Water

Banking Authority. The Authority is authorized to purchase unused Colorado River water and to store it in

groundwater basins to meet future needs. Conveyance

to storage areas is provided by the Central Arizona

Project. The legislation further provided that the Authority may enter into agreements with California and

Nevada agencies to bank water in Arizona basins, with

the following limitations:

• Regulations governing interstate banking would

need to be promulgated by the Secretary of the

Interior.

• The Arizona Department of Water Resources finds

that DOI’s regulations adequately protect Arizona’s

rights to Colorado River water.

• The ability to bank interstate water would be subordinate to banking of water to supply Arizona needs.

• Interstate banking would be precluded in years

when Arizona is using its full apportionment of

2.8 maf (including water being delivered to Arizona for banking by Arizona agencies), unless

surplus conditions were declared for the river system.

• Interstate withdrawals from the bank are limited

to 100 taf/yr, although there is no statutory limitation on annual deposits.

Under this legislation, future interstate banking

in Arizona would have a maximum annual yield of

100 taf. However, Arizona may effectively limit withdrawals in drought years by declining to decrease its

diversions of surface water to allow recovery of the

banked water. USBR released draft rules and regulations for the interstate banking program for public

comment in December 1997, and is presently reviewing the public comments.

Reoperating Colorado River System Reservoirs

Member agencies represented by the CRB have

discussed proposing reservoir operating criteria to the

Secretary of the Interior that would benefit California

while protecting the apportionments of the other basin states and satisfying Mexican treaty obligations.

Such criteria would also constitute part of the package

of actions for California to transition its use of river

water from current levels to 4.4 maf/yr. Operations

studies have evaluated specific shortage and surplus

criteria for the river system, including selection of desired probabilities for water supply reliability and

reservoir operating elevations.

Results of the operations studies performed by

CRB and by USBR suggest that there could be minimal hydrologic risk to using reservoir

reoperation—particularly as a limited-term measure

to help California reduce its Colorado River use—as

a water management option for this region. As

described in Chapter 3, the Colorado River has a high

ratio of storage capacity to average annual runoff. Projections of consumptive use for the upper basin states

suggest that those states will not attain full use of their

compact apportionments until after year 2060. USBR’s

surplus declarations to date have not adversely

impacted the other states’ use of their apportionments—for example, flood control releases were made

both in 1997 and 1998, and are expected in 1999.

The more significant impediment to implementing

reoperation would be concerns of the other basin states

about impacts of an extended period of reoperation

on future shortages, considering the river’s variable year

to year runoff.

For Bulletin 160-98, reservoir reoperation is not

evaluated as a water management option and no numerical evaluation is made, since consensus of USBR

and the basin states has not yet been obtained.

Weather Modification

A fundamental management issue associated with

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The California Water Plan Update BULLETIN 160-98

OPTIONS - EASTERN SIERRA AND COLORADO RIVER REGIONS 9-46

Colorado River water supplies is the apparent overstatement of the Compact apportionment relative to

the river’s historical hydrology. There have been proposals over the years to augment the river’s base flow

to provide additional supplies. For example, USBR had

developed a proposed pilot program in 1993 to evaluate cloud seeding potential in the Upper Basin. The

State of Colorado did not favor moving ahead with

this program.

Weather modification has recently been raised

again as part of a possible menu of options to resolve

California’s use in excess of the 4.4 maf basic apportionment, although no specific proposals have been

made. In concept, this option would entail cloud seeding in the Upper Basin to increase runoff, and might

yield a 5 percent increase in base flow from the area

seeded. Large-scale weather modification projects are

typically difficult to implement due to institutional

and third-party concerns, and can require several years

of study and testing prior to being placed in operational status. Weather modification on the Colorado

River is also complicated by interstate management

issues. This option has been deferred for these reasons.

Options for Coachella Valley

As discussed earlier, MWDSC has executed an

agreement with CVWD to study banking of surplus

Colorado River water, when available, in the lower

Coachella Valley. Banking programs typically entail

putting more water into the groundwater basin than

is extracted, to address losses and to avoid potential

localized impacts to existing basin pumpers. Over the

long term this extra recharge would help stabilize

groundwater basin levels. CVWD is presently in the

planning stages of expanding its existing pilot recharge/

extraction site in the lower valley. CVWD also plans

to form a groundwater replenishment district to help

manage overdraft.

MWDSC and CVWD are evaluating additional recharge possibilities in the Whitewater River drainage at

the north end of the valley. Water recharged in this area

could come from surplus Colorado River flows, from yearto-year purchases of SWP water or purchase of SWP

entitlement, or from other water marketing arrangements

that could take advantage of SWP/CRA conveyance. For

example, CVWD purchased about 39 taf of water from

other SWP contractors in 1996, on a one-time basis.

Additional recharge possibilities in the Whitewater drainage have not yet been quantified, and are not evaluated

further in Bulletin 160-98.

CVWD could, as other SWP urban water contractors are doing, participate in the permanent transfer

of agricultural entitlement water provided for in the

Monterey Agreement contract amendments. CVWD

could also purchase water from other sources, by way

of exchange with MWDSC, subject to negotiation of

conveyance in the SWP and CRA. Since no specific

proposals are currently pending, this option is not

quantified in the Bulletin.

Statewide Options

Statewide water supply augmentation options are

discussed and quantified in Chapter 6.

Options Likely to be Implemented

in the Colorado River Region

Applied water shortages are forecasted to be 147

taf in average years and 158 taf in drought years. Ranking of retained water management options for the

Colorado River Region is summarized in Table 9-23.

Table 9-24 summarizes options that can likely be implemented by 2020 to relieve the shortages.

Options identified for this region will likely be

used for reducing Coachella Valley overdraft and for

managing water to benefit the South Coast Region, as

called for in CRB’s draft 4.4 Plan. An evaluation of

these options is shown in Table 9A-3 in Appendix 9A.

Bulletin 160-98 assumes that water made available by

option implementation is first allocated to reduce overdraft within the region, and that remaining water is

then available for use in the South Coast Region.

For readers interested in comparing Bulletin 160-

98 options with the draft CRB 4.4 Plan, Table 9-25

summarizes the Bulletin’s findings in a format similar

to that used in the draft CRB 4.4 Plan. There is an

important differences between the two documents—

Bulletin 160-98 assumes that water conservation due

to EWMP implementation occurs as part of base demand forecasts and not as an optional measure. Actions

that may be implemented as part of phase two of the

draft CRB 4.4 Plan are not shown in the table, because

they have not yet been formulated and quantified.

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