Volume 3 Regional Reports

California Water Plan Update 2005

SAN LUIS

OBISPO

SANTA BARBARA

SAN

BENITO

MONTEREY

SANTA

CRUZ Flow in TAF

1998

83

2000

113

2001

152

San Joaquin River Region

San Felipe Unit (CVP)

Flow in TAF

1998

25

2000

31

2001

28

Tulare Lake Region

Coastal Branch California Aqueduct (SWP)

Flow in TAF

1998

66

2000

89

2001

133

San Francisco Bay Region

San Felipe Unit (CVP)

Some Statistics

 Area - 11,326 square miles (7.1% of State)

 Average annual precipitation - 18.7 inches

 Year 2000 population - 1,459,205

 2030 population projection - 1,890,390

 Total reservoir storage capacity - 1,227 TAF

 2000 irrigated crop area - 603,620 acres

.

.

.

.

.

.

Figure 4-1 Central Coast Hydrologic Region

The Central Coast Hydrologic Region extends from San Mateo to Santa Barbara counties and is within the Coast Range. Arrows indicate

annual flows entering and leaving the region for water years 1998, 2000, and 2001. 

Flow in TAF

1998

328

2000

276

2001

232

Outflow to Ocean*

*Outflow to Ocean includes Wild and Scenic Rivers, regulated flows, and estimated wastewater outflows.

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Chapter 4 Central Coast Hydrologic Region

portion is also in San Luis Obispo County. The Salinas and 

Santa Maria valleys are the premier agricultural production 

areas of the Central Coast. Other significant interior lowlands 

include San Benito Valley in the far north, the inland Cuyama 

Valley shared by San Luis Obispo and Santa Barbara counties, and the Lompoc and Santa Ynez valleys in Santa Barbara 

County. The single largest lowland in the region is the Carrizo 

Plain in the eastern backcountry of San Luis Obispo County. 

The Carrizo Plain is a very wide basin on the otherwise fairly 

narrow but notorious San Andreas Fault Zone, which runs the 

length of the region. 

The Central Coast’s rivers generally have a northwestsoutheast alignment, reflecting the topographic trend of 

the region’s mountains and hills. The Pajaro, Carmel, 

and Salinas rivers drain the northern part of this region, 

the Estrella River and San Juan Creek are in the central 

portion, and the Cuyama, Santa Maria, and Santa Ynez 

rivers are in the southern portion. All of the rivers within 

this hydrologic region drain into the Pacific Ocean.

Climate

The climate of the Central Coast region remains temperate 

all year due to its location adjacent to the Pacific Ocean. The 

Central Coast has a Mediterranean climate characterized 

by mild, wet winters, and warm, dry summers. The regional 

climate is dominated by a strong and persistent high-pressure 

system that frequently lies off the Pacific coast. This Pacific high 

shifts northward or southward in response to seasonal changes 

or the presence of cyclonic storms. Prevailing winds carry cool, 

humid marine air onshore. These northwest winds cause frequent fog and low clouds near the coast, particularly at night 

and in the morning in the late spring and early summer. San 

Benito County is the only county in the region that does not 

have a coastline. As a result, temperatures are often higher 

and fog is prevalent than in the other coastal counties.

Setting

The Central Coast Hydrologic Region extends from southern 

San Mateo County in the north to Santa Barbara County in the 

south (see Figure 4-1). The region includes all of Santa Cruz, 

Monterey, San Benito, San Luis Obispo and Santa Barbara 

counties and parts of San Mateo, Santa Clara, and Ventura 

counties. Many attributes define the Central Coast region 

including: the topography, many microclimates, the variety 

of agricultural products, and the picturesque coastline, valleys 

and communities that drive a thriving tourism economy.

Most of the Central Coast region is within the coastal 

mountain ranges, which stretch from the northern part of 

the region into San Luis Obispo and Santa Barbara counties. The portion of the Coast Ranges nearest to the ocean 

is the Santa Lucia Range, where elevations of a few peaks 

exceed 4,000 feet. Inland Coast Ranges are composed of 

the Gabilan and Diablo ranges in the north, the Cholame 

Hills in the center, and the Temblor and La Panza ranges 

in the south. The San Rafael and Sierra Madre mountains 

cover nearly three-quarters of Santa Barbara County. The 

southernmost quarter of Santa Barbara County is covered 

by the Santa Ynez Mountains, which are a component of 

another landform, the east-west trending Transverse Ranges. 

The mountains in eastern Santa Barbara County attain elevations of about 7,000 feet. 

Lowlands in the region include narrow streambeds winding to 

the coast, coastal terraces and plains of varying sizes, and a 

few larger river valleys. The largest lowland near the coast is 

the Salinas Valley. Although less than 10 miles wide for most of 

its length, it stretches for 120 miles from the community of Moss 

Landing on Monterey Bay southeastward to near the community 

of Santa Margarita in San Luis Obispo County. Pajaro Valley 

is a smaller coastal valley adjacent to the Salinas Valley on the 

north side of Monterey Bay. Another large lowland near the 

coast is Santa Maria Valley, which straddles the Santa Maria 

River. Most of this valley is in Santa Barbara County, but a 

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California Water Plan Update 2005

4 2 Volume 3 Regional Reports

January is the coolest month with an average high temperature 

of 59 degrees and low temperature of 41 degrees. September 

is the warmest month with 72 degrees as the average high 

temperature and 52 degrees lowest. In the northern part of 

the region, the best weather occurs in September and extends 

through the middle of November with a few days getting into 

the 80s and 90s. Summer temperatures are cool along the 

coast and warmer inland. In the winter, temperatures remain 

cool along the coast but become cooler inland. The yearround, frost-free climate of the coastal valleys makes them ideal 

for specialty crops such as strawberries and artichokes. 

Annual precipitation—usually rain—in the region ranges 

from 14 to 45 inches. Most of the rain occurs between late 

November and mid-April. The average annual precipitation 

near Salinas is about 14 inches. The southern interior basins 

usually receive 5 to 10 inches per year, with the mountain 

areas receiving more rainfall than the valley floors. The vineyard-growing areas throughout the region generally have 

summers that are long and cool due to the influence of the 

ocean. High-quality wine grapes thrive in this environment with 

very moderate climate all summer, with foggy mornings, bright 

sunshine through the afternoon, and very windy afternoons 

and early evenings.

The Monterey area, in general, enjoys the mildest climate with the 

fewest hot and cold days of any place in the continental United 

States. A prevailing feature of summer weather is the coastal fog 

or stratus overcast. The low overcast or fog usually burns off in 

the late morning and moves back in before midnight. During the 

winter, the coolest areas are inland away from the ocean. Winds 

are lightest in the winter and strongest in the summer, except for 

occasional storms.

The most prominent feature in the region is the floor of the Salinas Valley, which is about 7 miles wide at Chualar, 9 miles wide 

at Greenfield, and 4 miles wide at King City. The microclimate 

in these coastal areas (Salinas, Pajaro, and Santa Maria valMost of the Central Coast region is within the coastal mountain ranges, which stretch from the northern part of the region into San Luis Obispo and Santa 

Barbara counties. Lone Cypress is a landmark on the Monterey Peninsula. (DWR Photo)

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California Water Plan Update 2005

leys) is ideal for growing truck crops and are well known for 

growing lettuce, broccoli, mushrooms, strawberries, citrus, and 

several other crops. The microclimate in these coastal areas is 

also ideal for the fl oral industry and grape vineyards. 

At the very southern end of the region is Santa Barbara County. 

Summers are warm and dry; the winters are cool and often 

wet. The county has a unique physical orientation, with a series 

of east-west transverse mountain ranges. This can sometimes 

produce a profound orographic effect when storms approach 

the county from the Pacifi c Ocean. Most rain occurs between 

November and March. For the most part, Santa Barbara County 

receives relatively gentle but steady rainfall during storm events. 

Moist air from the Pacifi c Ocean moderates temperatures 

in the coastal areas, and somewhat lower winter minimums 

and higher summer maximums prevail in the inland valleys. 

Population

The population of the Central Coast Region was about 

1,459,200 in 2000, slightly more than 4 percent of California’s population. About 65 percent of the Central Coast 

population lives in incorporated cities, which include Salinas 

(143,800), Santa Barbara (89,600), Santa Maria (77,400), 

Santa Cruz (54,600), San Luis Obispo (44,200), Lompoc 

(41,100), Watsonville (44,300), Hollister (34,400), Seaside 

(33,500), Monterey (29,700), Atascadero (26,400), and 

Paso Robles (24,300). There are several communities in the 

region with populations of fewer than 20,000. 

California experienced a population increase approaching 

14 percent from 1990 to 2000, while the growth in Central 

Coast Region was nearly 14 percent. Most of the counties 

in the Central Coast region reached double-digit population 

growth rates during these 10 years. The only county with a 

growth rate below double digits, according to Department 

of Finance population statistics, was Santa Barbara County, 

which grew by slightly less than 9 percent. San Benito County 

exceeded all other counties by recording a 46 percent 

increase during the decade. The population growth rates 

for Monterey County, San Luis Obispo County and Santa 

Cruz County were 13 percent, 14 percent, and 12 percent, 

respectively. Looking to the future, California Department 

of Finance estimates that the population of this hydrologic 

region will grow to roughly 1,890,400 by year 2030, which 

represents a 30 percent increase from 2000. Figure 4-2 

Figure 4-2 Central Coast Hydrologic Region population

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

2,000,000

1960 1970 1980 1990 2000 2010 2020 2030

Data from California Department of Finance provide decadal population from 1960 to 2000, and population projection for 2030 for the 

Central Coast region. 

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4 4 Volume 3 Regional Reports

provides a graphical depiction of the Central Coast Region’s 

population from year 1960 through 2000, with projections 

to year 2030. 

Population growth in the region is largely constrained by 

land-use policies, which limits the development of new housing. The cost of homes in most of the region is well above the 

national average, with the most costly real estate near the 

Santa Cruz and Monterey bays, Santa Barbara and greater 

Salinas area. As with most communities facing high real 

estate prices, there is a lack of entry and mid-level housing. 

Prices have been driven up by a lack of new development 

combined with a high demand by people moving into this 

region. The high cost of housing in the city of Santa Barbara 

is resulting in a ‘flight to affordability,’ as more workers are 

commuting into the city from nearby Santa Maria and the 

Santa Ynez Valley. Likewise, workers also commute to jobs 

in the major metropolitan areas from communities such as 

Salinas, Hollister, and some locations in the San Joaquin 

Valley, including Tracy, Los Banos, Patterson, and Modesto. 

Land Use

The busy topography of the Central Coast Region and distance 

from California’s major population centers have resulted in a 

landscape that is primarily pastoral and agricultural. Major 

economic activities include tourism, agricultural-related processing, as well as government and service-sector employment. 

Oil production and transportation sites onshore and offshore 

are important to the economy.

Agriculture in the Central Coast region can be divided into two 

distinct categories. One is irrigated vegetable and specialty 

crops grown on coastal terraces and valleys and in some 

inland valleys; and the other category is range pasture and 

dry-farmed grain in the inland valleys. The acreage planted 

in wine grape is expanding rapidly and now represents the 

region’s highest-value individual agricultural commodity. Vineyard acreage region-wide grew 34 percent between 1998 and 

2001. Although wine grapes are the highest-value individual 

agricultural commodity in the region, the category of vegetable 

crops still generates the highest dollar value. Livestock operations, mainly cattle, also are significant in the region. 

Total irrigated land acreage in the Central Coast region has 

increased slightly from 422,000 acres in 1990 to 438,800 

acres in 2000, or about 4 percent. However, because of the 

significant increase in the practice of growing multiple crops 

in a single year on the same piece of land, the total crop 

acreage increased from 534,400 acres in 1990 to 605,000 

acres in 2000, a 13 percent increase. This increase in farm 

productivity through multi-cropping is a practice that is applied 

primarily to vegetable crops because of their relatively short 

growing season.

The acreage of field crops in the region has been declining for 

several years. It is now rare to find sugar beets grown in the 

region, and the two processing plants in Spreckles and Santa 

Maria that once took delivery of local sugar beets have both 

closed. Other field crops whose production has declined are 

corn, alfalfa, and irrigated pasture. However, the loss of field 

crop acreage has been offset by the increases in vegetable 

and truck crops. According to Monterey County Agricultural 

Commission statistics, lettuce acreage was 58,000 acres in 

1990, and by year 2000 it had increased to 106,000 acres. 

Value-added products such as packaged salads, baby lettuce 

mixes, and specialty bag mixes have created a large demand 

for the many types of lettuce grown in the region, as well as 

for specialty greens. 

The two premier vegetable-growing centers in the Central 

Coast region are the highly productive Salinas Valley in the 

north and the smaller Santa Maria Valley in the south. Yearround multiple cropping of vegetables is the predominant farm 

practice in these areas. The results from a multiple cropping 

field study conducted by the Department of Water Resources in 

the Salinas Valley in 1997 indicated that more than 100,000 

acres was multiple cropped, which is about 40 percent of the 

irrigated land in the northern half of this hydrologic region. 

From 1992 to 1998, the region lost more than 14,400 acres 

of agricultural land to urban uses (California Department of 

Conservation figures). However, growers have compensated 

for the loss of agricultural land through increased use of multicropping and the use of nonirrigated pasture lands. In 2001 

over 250,000 acres of land was devoted to the production of 

irrigated vegetables and specialty crops. However, because 

of multi-cropping practices, over 400,000 acres of specialty 

crops were harvested.

Citrus and subtropical fruit crops, chiefly avocados and 

lemons, are grown on nearly 14,000 acres in the southern 

parts of this region. More than three-quarters of this acreage 

is near Santa Barbara. Nearly 14,000 acres of irrigated 

deciduous fruit trees, mostly walnuts, are also grown in the 

region, primarily in San Luis Obispo and San Benito counties. 

Vineyard acreage is evenly distributed between the northern 

and southern parts of the region. However, the vineyard acreage in the southern areas has grown rapidly from 27,100 

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Chapter 4 Central Coast Hydrologic Region 4 5

California Water Plan Update 2005

acres in 1998 to 46,500 acres in 2001. Total grape acreage 

for the full hydrologic region grew from 68,100 to 95,600 

acres between 1998 and 2001. Wineries with tasting rooms 

have become an important part of the region’s travel and 

tourism industry. 

Publicly owned lands, including military reservations, federally managed areas, and parks, make up about 28 percent 

of the Central Coast region. One of the main environmental 

water uses in the region is for the Salinas River National 

Wildlife Refuge, which is on 366 acres where the Salinas 

River empties into Monterey Bay. The refuge is part of the 

San Francisco Bay National Wildlife Refuge Complex, 

headquartered in Fremont. Refuge lands include a range 

of terrestrial and aquatic habitats, including coastal dunes 

and beaches, grasslands, wetlands, and riparian scrub. 

Because this wildlife refuge is within the Pacific Flyway, it 

is used by a variety of migratory birds for breeding, wintering, and rest stops during migration. It also provides 

habitat for several threatened and endangered species. 

Water Supply and Use

Groundwater is the primary source of water in the region, 

accounting for roughly 75 percent of the annual supply in 

2000. Local and some imported surface water supplies make 

up the rest of the available water for this region. A significant 

amount of groundwater recharge is provided by the Pajaro, 

Salinas, and Carmel rivers, and by the Arroyo Seco, which 

flows into the Salinas River. Also, some water from local reservoirs is used to recharge groundwater. San Clemente and 

Los Padres dams on the Carmel River in Monterey County, 

San Antonio Dam on the San Antonio River, also in Monterey 

County, and Nacimiento Dam on the Nacimiento River in 

San Luis Obispo County are the region’s main reservoirs. 

Figure 4-3 shows all of the water supply sources used to meet 

developed water uses in the region for 1998, 2000, and 

2001 and summarizes all of the dedicated and developed 

urban, agricultural and environmental water uses within this 

hydrologic region for those years.

Water agencies in the northern half of this region include 

Monterey County Water Resources Agency, Monterey Peninsula Water Management District, Marina Coast Water 

District, California American Water, California Water Service 

Co., Sunnyslope County Water District, Pajaro Valley Water 

Management Agency, the City of Santa Cruz, San Benito 

County Flood Control and Water Conservation District, and 

a portion of the Santa Clara Valley Water District (Llagas 

subbasin). Water agencies in the southern parts of the region 

include the San Luis Obispo County Flood Control and Water 

Conservation District and the Santa Barbara County Flood 

Control and Water Conservation District and numerous cities, 

special districts, community services districts, and public utility companies. The Central Coast Water Authority is a larger 

regional agency that includes many of the individual water 

entities as members.

Historically, almost all of the applied irrigation water was 

developed from groundwater until the San Felipe Unit of the 

U.S. Bureau of Reclamation’s Central Valley Project began 

importing surface water for irrigation in June 1987. The CVP’s 

contracts for deliveries to the Santa Clara Valley Water District 

and the San Benito County Water District from the San Luis 

Reservoir total 196,300 acre-feet per year, which includes 

138,250 acre-feet per year for municipal use and 58,050 

acre-feet per year for agricultural uses. There are two other 

USBR projects in the region. The Cachuma Project provides 

Santa Ynez River water to the communities of Carpinteria, 

Goleta, Montecito, Santa Barbara, and Santa Ynez from the 

190,000 acre-foot Cachuma Reservoir through the Tecolote 

Tunnel and South Coast Conduit. The USBR also operates the 

Santa Maria Project, which provides water from Twitchell 

Reservoir on the Cuyama River for irrigation purposes in the 

Santa Maria area. Another federal reservoir, the U.S. Army 

Corps of Engineer’s 26,000 acre-foot Santa Margarita Lake 

provides water to the city of San Luis Obispo. The 40,700 

acre-foot Whale Rock Reservoir near Cayucos is owned by 

the Whale Rock Commission and provides water to the City 

of San Luis Obispo and surrounding communities. Surface 

water is also imported into the region through the State Water 

Project’s Coastal Branch Aqueduct, which was completed in 

1997 and can deliver up to 70,500 acre-feet per year into 

San Luis Obispo and Santa Barbara counties. 

California American Water, which is the primary urban water 

supplier to about 100,000 residents on the Monterey Peninsula area, currently (year 2004) obtains about 75 percent 

of its water from wells in the Carmel Valley alluvial aquifer. 

The remaining 25 percent is supplied from wells in Seaside 

Basin groundwater aquifers. No water is produced by direct 

diversion from San Clemente Reservoir on the Carmel River 

as a result of operational changes due to dam seismic safety 

concerns. In recent years, the State Water Resources Control 

Board regulation has limited available supplies, such that new 

water supply sources must be developed before additional 

regional growth can be supported. Although CaliforniaAmerican Water Company had previously proposed building 

a new dam on the Carmel River, the company is now studyEE-RM-PET-100 C0MMENT 01A
California Water Plan Update 2005

4 6 Volume 3 Regional Reports

Figure 4-3 Central Coast region water balance for water years 1998, 2000, 2001

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

1998 2000 2001

Thousand Acre-Feet

Wild & Scenic

R.

Instream Flow

Irrigated

Agriculture

Urban

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

1998 2000 2001

Thousand Acre-Feet

Dedicated

Environ

Reuse &

Recycle

Ground Water

State Project

Federal

Projects

Local Projects

Dedicated Water Supplies

Applied Water Uses

Three years show a marked change in amount and relative proportions of water delivered to Central Coast region’s urban and agricultural 

sectors and water dedicated to the environment (applied water, top chart), where the water came from, and how much water was reused 

among sectors (dedicated water supplies, bottom chart).

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Chapter 4 Central Coast Hydrologic Region 4 7

California Water Plan Update 2005

ing an alternative plan called the Coastal Water Project. This 

project proposes an ocean desalination plant in the Monterey 

Bay region and development of a conjunctive groundwater 

storage program for the aquifer in the Seaside area. Additional planning studies, environmental impact analysis, and 

regulatory agency approvals must be completed before new 

water supply facilities can be completed.

Desalination of seawater is another source of water within this 

region. The 1987-1992 drought resulted in the construction 

of several small seawater desalting plants. The city of Santa 

Barbara built an 8-million gallons per day plant that was to 

provide water during water shortages. However, this plant is 

now inactive, and most of its equipment has been removed. 

A small plant also was built for the California Department of 

Parks and Recreation at the San Simeon Beach State Park to 

serve the Hearst Castle Visitor’s Center. That plant was removed 

when a surface water alternative was later acquired. The city 

of Morro Bay built a seawater desalting plant and still operates it intermittently during water shortages. 

Today, there are seven small seawater-desalting plants along 

the Central Coast. Of these, only one, Marina Coast Water 

District, provides municipal water, but it is currently not being 

used. The other six provide water for offshore islands or for 

industrial use. There are several large (greater than 1-million 

gallons per day) seawater desalting proposals under consideration by agencies in the Monterey-Santa Cruz area. If 

approved and constructed, the total capacity of these proposed 

plants could be about 20,000 acre-feet per year. Farther to 

the south, there is also a smaller desalting plant under study 

to supplement water supplies for the Cambria area.

Water recycling is also becoming a more important water 

resource. For example, Santa Barbara County has three 

wastewater treatment plants that recycle wastewater for irrigation, and dust control and compaction at construction sites. In 

addition, Laguna Sanitation District is designing wastewater 

treatment and recycled water distribution plants that will be 

used to serve a golf course and several other irrigation water 

customers in the city of Santa Maria.

Monterey County has two major wastewater recycling projects. 

The Castroville Seawater Intrusion Project provides approximately 19,000 acre-feet per year to replace coastal groundwater pumping for irrigating vegetables and fruit crops. The 

Carmel Area Wastewater District/Pebble Beach Community 

Services District Reclamation Project replaces approximately 

700 acre-feet of potable water for golf courses and other open 

space in Pebble Beach.

Table 4-1 provides information about the water and its uses 

in the region for 1998 (a very wet year), 2000 (a year with 

slightly above normal precipitation), and 2001 (a below 

average precipitation year for most of the state, but slightly 

above average for the Central Coast region). Agriculture is 

the main user of water in this region, accounting for roughly 

71 percent of the region’s total water use in year 2000. Environmental water use consists primarily of the river flows from 

two federally designated wild and scenic rivers, the Big Sur 

River and the Sisquoc River. Because the flow of these two 

rivers varies considerably depending on the type of water year, 

total environmental water use can be as much as 24 percent 

of all uses in a wetter year (1998), or as little as 5 percent of 

the total water use in a drier year. Urban water use is about 

21 percent of the total developed and dedicated water uses 

in the Central Coast region.

Per capita urban water use in many parts of the region 

remains at or below urban usage levels from the late 1980s. 

This decline can be traced to the aggressive use of water 

conservation programs and mandatory water use reductions 

during the 1987-1992 drought. The city of Santa Barbara is 

a good example. Shortages from one of its major supplies, 

the Cachuma Reservoir Project, forced the city to intensify 

its conservation and rationing. In 1988, the average daily 

per capita water use for Santa Barbara was estimated at 

164 gallons per day. That value dropped to 94 gallons per 

capita day during the worst part of the drought in 1990. 

More recently, year 2000 estimated water use was 133 gallons per day, which is still about 20 percent lower than per 

capita usage in 1988. Similar trends toward improved water 

conservation and lower per capita water use have occurred 

in many other urban areas of the Central Coast region. 

State of the Region

Challenges

With the Central Coast’s limited surface water supply and few 

large surface water storage facilities, the growing demand for 

water is leading to more dependence on groundwater. In some 

of the coastal groundwater basins, groundwater is pumped at 

a higher rate than the underground supply can be replenished, 

such that seawater has pushed into some coastal freshwater 

aquifers and is degrading groundwater quality. There are 

some places, such as the Seaside Groundwater Basin and the 

Carmel River Groundwater Basin in the Monterey Peninsula 

Water Management District, where seawater intrusion has 

been prevented by rigorous monitoring and management to 

limit groundwater well production to safe yields. However, in 

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Water Entering the Region 

Precipitation 25,202 12,596 11,848

 Inflow from Oregon/Mexico 0 0 0

 Inflow from Colorado River 0 0 0

 Imports from Other Regions 108 144 180

Total 25,310 12,740 12,028

Water Leaving the Region 

Consumptive Use of Applied Water * 622 754 860

 (Ag, M&I, Wetlands) 

 Outflow to Oregon/Nevada/Mexico 0 0 0

 Exports to Other Regions 66 89 133

 Statutory Required Outflow to Salt Sink 174 95 49

 Additional Outflow to Salt Sink 154 181 183

 Evaporation, Evapotranspiration of Native 

 Vegetation, Groundwater Subsurface Outflows, 24,502 12,362 11,688

 Natural and Incidental Runoff, Ag Effective 

 Precipitation & Other Outflows 

Total 25,518 13,481 12,913

Storage Changes in the Region

 [+] Water added to storage

 [-] Water removed from storage 

 Change in Surface Reservoir Storage 401 8 -14

 Change in Groundwater Storage ** -609 -749 -871

Total -208 -741 -885

Applied Water * (compare with Consumptive Use) 1,074 1,291 1,442

*Footnote for applied water

Consumptive use is the amount of applied water used and no longer available as a source of supply. Applied water is 

 greater than consumptive use because it includes consumptive use, reuse, and outflows. 

**Footnote for change in Groundwater Storage

Change in Groundwater Storage is based upon best available information. Basins in the north part of the 

state (North Coast, San Francisco, Sacramento River and North Lahontan regions and parts of Central 

 Coast and San Joaquin River regions) have been modeled – spring 1997 to spring 1998 for the 1998 

 water year and spring 1999 to spring 2000 for the 2000 water year. All other regions and year 2001 were 

 calculated using the following equation: 

GW change in storage =

 intentional recharge + deep percolation of applied water + conveyance deep percolation - withdrawals

This equation does not include the unknown factors such as natural recharge and subsurface inflow and outflow.

 Water Year (Percent of Normal Precipitation) 

1998 (225%) 2000 (110%) 2001 (107%)

Table 4-1 Central Coast Hydrologic Region water balance summary - TAF

Water Entering the Region – Water Leaving the Region = Storage Changes in Region

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California Water Plan Update 2005

other coastal areas such as the mouth of the Salinas River, 

seawater intrusion into the groundwater aquifer is a major 

threat to water quality.

Unique coastal resources, such as Morro Bay and Monterey 

Bay, as well as the Salinas Valley, are the focus of water quality 

issues. Sedimentation poses the greatest water quality threat 

to Morro Bay, one of 28 estuaries in the National Estuary 

Program. The bay is also contaminated by pathogens from 

agriculture, boats, and urban runoff; nutrients from fertilizers, 

animal wastes, and urban runoff; heavy metals from abandoned mines in the upper watershed; and offshore boatyards 

that contaminate sediment. Elevated levels of bacteria have 

closed many of the shellfish growing beds in Morro Bay, and 

have occasionally closed beaches in Santa Cruz County and 

southern Santa Barbara County. To protect special areas 

of biological significance, waste discharges are prohibited 

or limited in portions of Monterey Bay, a National Marine 

Sanctuary, and other specific coastal and ocean waters of the 

region. In its triennial review, the Central Coast Regional Water 

Quality Control Board also identified the need to incorporate 

new microbiological standards for water-contact recreation 

in this region. 

In the southern portion of Santa Clara County, elevated concentrations of nitrate and perchlorate have been detected. The 

Santa Clara Valley Water District continues to implement a 

Nitrate Management Program to monitor nitrate occurrence, 

reduce nitrate exposure, and reduce nitrate loading throughout Santa Clara County. The district also provides in-field 

technical assistance to the regions agricultural growers about 

nitrate and irrigation management. In late 2002, perchlorate 

(a chemical used in the manufacture of rocket fuel, road 

flares, and fireworks), emerged as a significant groundwater 

contaminant in the southern end of Santa Clara County. The 

known extent of this groundwater chemical plume extends 

10 miles, and more than 800 water supply wells have been 

affected. The Santa Clara Valley Water District is working with 

the Regional Water Quality Control Board, local agencies, and 

affected communities to develop and implement a long-term 

corrective action plan. 

The Salinas River watershed has significant nitrate contamination related to agriculture, the valley’s main land use. Groundwater overdraft is also a problem in the area, and seawater 

has now intruded 6 miles inland into the shallow groundwater 

aquifer around Castroville. The nearby Pajaro River watershed faces a variety of water quality threats, such as erosion 

(primarily from agricultural practices), urban runoff, sand 

and gravel mining, flood control projects, off-road vehicles, 

and historical mercury mining in the Hernandez Lake area. 

Coastal wetlands in Elkhorn Slough, a tributary to Monterey 

Bay between the Salinas and Pajaro rivers, suffer from erosion on strawberry and other cropped lands in its watershed. 

Elevated bacterial levels in the slough may be associated with 

a large dairy and waste operation in the watershed as well as 

septic tanks. In addition, more than 600 year-round vessels 

use the Moss Landing Harbor, which increases the waste load 

to the slough. The accumulated effects of these water quality 

problems, along with the resuspension of pesticides in sediments, have restricted shellfish growing in Elkhorn Slough. 

Other regional water quality concerns include one of the 

nation’s worst oil spills at Unocal’s Guadalupe Oil Field in 

the Santa Maria River watershed. Nutrients and pathogens 

impact the San Lorenzo River Basin, from septic systems, horse 

corrals, and urban runoff, as well as erosion from logging, 

urban development, and road maintenance. Groundwater 

basins that are impacted by salinity include the Hollister area, 

the Carrizo Plain, the Santa Maria and Cuyama valleys, San 

Antonio Creek Valley, portions of the Santa Ynez Valley, and 

the Goleta and Santa Barbara areas. 

California American Water is the primary water supplier 

to most of the Monterey Peninsula, and the Carmel River is 

its primary source of water. In 1995, a major State Water 

Resources Control Board order ruled that the company did 

not have a legal right to roughly 70 percent of the surface 

water it had been diverting from the Carmel River. As a result, 

California American Water has been forced to take more 

water from wells that draw from groundwater below the lower 

valley, in order to keep as much water as possible in the river. 

Essentially no surface water is now taken from the river’s two 

reservoirs behind the San Clemente and Los Padres dams for 

municipal supply purposes. To offset this lack of surface water, 

California American Water and the Monterey Peninsula Water 

Management District have each made separate proposals 

for seawater desalination plants that would produce enough 

water to satisfy the state order and put a minimum of 8,000 

acre-feet of water a year back into the Carmel River. However, 

as proposed neither project will be able to supply water for 

future urban growth and in-fill housing needs. 

Accomplishments

Many water districts have programs to monitor, evaluate, 

and better manage their groundwater resources. Watershed 

programs are under way to reduce nonpoint pollution, reduce 

stream erosion, and improve riparian vegetation. For example, 

the Coastal Watershed Council was formed in response to 

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4 10 Volume 3 Regional Reports

the declining health of the watersheds of the Monterey Bay. 

Its mission is to restore the watersheds of the region and 

teach its residents how to become stewards of their creeks 

and streams.

The Carmel River Basin, though small compared to other 

watersheds, supports a key run of steelhead, a federally listed 

species. The Monterey Peninsula Water Management District 

has a program to offset the environmental effects of diversions 

from the Carmel River that are required to meet the peninsula’s 

water needs. Activities include steelhead rescues when the river 

is dry, fish rearing and release, restoring riparian habitat, and 

protecting riverbanks. MPWMD works with others, including 

the Carmel River Steelhead Association and the Carmel River 

Watershed Conservancy.

In January 2003, the Pajaro Valley Water Management 

Agency attempted to negotiate a $25 million agreement for 

water to be acquired from the Central San Joaquin Valley’s 

Broadview Water District near the city of Firebaugh in Fresno 

County. Because of agricultural drainage and economic problems, Broadview Water District farmers have allowed about 

one-third of their 9,100 acres to lie fallow in recent years, while 

selling part of their contracted CVP water deliveries. The proposed agreement was intended to implement part of the Pajaro 

Valley Water Management Agency’s plan to use imported 

surface water as an alternative source, which would reduce 

groundwater over-pumping and, thus, seawater intrusion. The 

negotiations between Pajaro Valley and Broadview Water 

District continued into 2004; but unfortunately the deadline 

to complete an agreement passed without a final pact being 

negotiated. Subsequently, Westlands Water District initiated 

discussions with Broadview Water District for the purchase of 

district lands and the CVP water. In a notice it sent to district 

landowners in September 2004, Westlands stated that the 

negotiations had been completed, and it hoped to finalize the 

agreement by February 2005. 

In 1998, the Monterey County Water Resources Agency 

and the Monterey Regional Water Pollution Control Agency 

(RWPCA) completed a $78 million Salinas Valley reclamation project and Castroville seawater intrusion project. These 

two projects consist of a 19,500 acre-feet per year tertiary 

treatment plant and a distribution system that provides about 

13,000 acre-feet of recycled water to 12,000 acres of Castroville area farms. During periods of the low irrigation demand 

in the winter, early spring and late fall, this recycled water 

supplies most of the water needed for irrigation. These projects 

will reduce groundwater pumping in the project area, and thus 

are expected to reduce seawater intrusion. Another project 

that will help alleviate Salinas Valley’s seawater intrusion is 

the $18.8 million Salinas Valley Water Project. The project 

has two parts: (1) a seasonal rubber dam on the Salinas 

River near Marina to deliver more fresh water to the saltwater-plagued areas near Castroville and (2) the modification 

of upstream river operations at San Antonio and Nacimiento 

lakes to provide higher summer flows to recharge Salinas Valley 

aquifers. Final planning, financing, and permit approvals are 

being obtained, and it is anticipated that this project will be 

constructed in year 2005. 

A regional approach to water supply development has been 

evolving in recent years in San Luis Obispo County. By setting 

aside regional disagreements the City of San Luis Obispo and 

Paso Robles, as well as the County of San Luis Obispo, Atascadero Mutual Water Company, and the Templeton Community 

Services District have agreed to build the Nacimiento Water 

Project to convey water via pipeline from Lake Nacimiento 

to the City of San Luis Obispo and locations in between. The 

county has had rights to 17,500 acre-feet of water per year 

from Lake Nacimiento since 1959, and recently approached 

various water agencies and public entities within its boundaries to discuss use of this untapped supply. Currently, the 

cost of construction for this proposed project is estimated to 

be about $150 million. Proposed water purchases to fund 

this project currently anticipate (1) $51 million from Paso 

Robles for 4,000 acre-feet per year, (2) $ 30 million from 

Atascadero Mutual for 2,000 acre-feet per year, (3) $ 64 

million from City of San Luis Obispo for 3,380 acre-feet per 

year, and (4) $ 3.6 million from Templeton CSD for 250 acrefeet per year. The project design is now under way, and the 

proposed schedule anticipates that construction would start 

in early 2007 and be completed by the end of year 2009. 

Relationship with Other Regions

Historically, the communities of the Central Coast region have 

relied on local surface water and groundwater supplies to 

meet their needs. The northern part of the region first received 

imported water with completion of the San Felipe Unit of the 

federal CVP in 1987. This facility delivers water to San Benito 

County users primarily for agricultural purposes from San Luis 

Reservoir in the San Joaquin River Hydrologic Region. Ten 

years later, the Coastal Branch of the SWP was completed to 

import water to San Luis Obispo and Santa Barbara Counties 

from the California Aqueduct in the Tulare Lake Hydrologic 

Region. There are no other water imports into the Central Coast 

region. Because there is seldom any excess surface water in 

this region’s watersheds, there are no water exports from this 

region to other parts of the state.

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California Water Plan Update 2005

Looking to the Future

Local water agencies in the Central Coast Hydrologic Region 

are continually maintaining, servicing, expanding, and 

updating their water systems (Box 4-1 Ongoing Planning 

Efforts). Because groundwater is the primary water source 

for the Central Coast region, water agencies are actively 

combining groundwater and surface water components into 

conjunctive use projects. In addition to the implementation 

of water conservation programs, other water management 

strategies that are under consideration include recycling, 

groundwater recovery, water marketing, and desalination. 

Regional Planning

Several water agencies, including Marina Coast Water District 

and Scotts Valley Water District, are developing groundwater 

management plans and conducting groundwater studies to fill 

in information gaps about local groundwater conditions.

In its effort to implement its Basin Management Plan (BMP) 

Alternative B, the Pajaro Valley Water Management Agency 

(PVWMA) has purchased rights to CVP water from the Mercy 

Springs Water District (6,250 acre-feet). The PVWMA has also 

begun pipeline construction to deliver Harkins Slough Project 

and supplemental well water to coastal growers whose wells 

have been contaminated by seawater, and is pursuing more than 

$50 million in State and federal grants to implement the BMP. 

The BMP includes new wells, as a supplemental supply and as 

a source of blend water for wastewater reclamation, and an 

injection/recovery program for CVP water. 

The Monterey Peninsula Water Management District has carried out a multiyear aquifer storage and recovery test program, 

where excess winter flow from the Carmel River is treated and 

injected into the Seaside Basin for recovery during dry periods. 

MPWMD has also funded several hydrogeologic studies of the 

Seaside Basin, and is in the process of developing a Seaside 

Basin Groundwater Management Plan. 

Many projects and studies are under way in the Central Coast 

Region to enhance water quality and supply. Several new 

ocean desalination plants, such as the desalination project 

in the Sand City area being studied by Monterey Peninsula 

Water Management District, are being investigated as potential sources of new water supplies. Many agencies are also 

considering recycled water projects in conjunction with the 

construction of new or expanded municipal wastewater treatment plants. Local water users are proposing to raise the height 

of USBR’s Bradbury Dam (Cachuma Reservoir) up to 3 feet 

to provide more water supply for the enhancement of downstream fish habitat. Additionally, many watershed programs 

are under way to remediate pollution and sedimentation, to 

help flood control, and to protect and restore ecosystems. 

Water Portfolios for Water Years 1998, 

2000, and 2001

Water Year 1998

California experienced a very wet winter in 1998 related to 

the El Nino weather pattern. Because of the extensive damage 

caused by El Nino storms, the winter of 1998-99 ranked as the 

10th costliest in California history. Particularly hard hit were 

the coastal valleys, where many agricultural fields remained 

wet and soggy for the first six months of 1998. Annual rainfall 

in the Santa Cruz area exceeded 30 inches (193.5 percent of 

normal), and in the southern part of this region the Santa Barbara NWS station measured almost 47 inches of rainfall (167 

percent of normal). For the entire hydrologic region, average 

annual precipitation was 225 percent of normal amounts, 

compared to a statewide average of 171 percent of normal 

annual precipitation. 

Total agricultural production in the region was $3.65 billion 

(Monterey, Santa Cruz, San Benito, San Luis Obispo, and Santa 

Barbara counties) in 1998 from 564,600 acres of harvested 

irrigated crops. This is only a modest increase over 1997, but it 

is significant considering some of the challenges that the agriBox 4-1 Ongoing Planning Efforts

• Carmel River Management Plan

• Carmel River Watershed Council

• Coastal Watershed Council

• Pajaro River Watershed Council

• Pajaro Valley Groundwater Management Plan

• Salinas Valley Water Plan

• Santa Clara Valley Water District Groundwater 

Management Plan

• Seaside Basin Groundwater Management Plan

• Upper Salinas River Watershed CRMP

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4 12 Volume 3 Regional Reports

cultural industry faced. Most of the farming along the Central 

Coast involves vegetable crops, and vegetable crop acreage 

accounted for 72 percent of all irrigated crop acreage. The next 

largest crop is grapes comprising 12 percent of irrigated crop 

acreage. The Salinas Valley area produces the majority of the 

spring and summer vegetable crops, particularly lettuce. 

The impact of the wet El Nino phenomenon on the Central 

Coast region’s precipitation was very significant. Growers had 

little need to irrigate crops during the first four to five months of 

1998. The very wet conditions prevented the timely planting of 

many acres of truck crops. Spring rains delayed planting and 

negatively affected growing conditions, especially for head 

lettuce production. There was also a decrease in the value of 

wine grapes due to the cool wet conditions, even though the 

acreage of grapes planted continued to increase. Strawberry 

acreage was slightly less than the prior year, but total strawberry crop value rose due to a shortage early in the season, 

resulting in higher prices once the berries were harvested. 

The most significant crop increase in 1998 was attributed 

to value-added salad products, for which the product value 

increased by about $70 million as consumer demand grew. 

Head lettuce value significantly dropped, primarily as a result 

of wet spring conditions. 

As shown in Table 4-2 the 1998 total on-farm agricultural 

applied water use in the Central Coast Region was 816,300 

acre-feet while total agriculture water use (including conveyance 

losses) was 829,000 acre-feet, or 58 percent of all uses, which 

is lower than normal as a result of the heavy precipitation. On 

a per acre basis, the average on-farm unit applied water was 

only 1.4 acre foot per acre in 1998. For comparison, year 

1995 applied water was over 2 acre-feet per acre. As would 

be expected, this information verifies that the amount of water 

needed to irrigate crops is generally much less than normal 

during wetter years, due to utilization of the effective rainfall. 

The total agricultural evapotranspiration of applied water, or 

ETAW, in 1998 amounted to 556,900 acre-feet. The regional 

average unit ETAW was one acre-foot per acre. 

Total urban applied water, including residential, commercial, 

industrial, and landscape uses, in the region was 261,500 

acre-feet for the year. As shown in Table 4-2, urban water use 

accounted for roughly 18 percent of the region’s total water 

use. Based on available water agency information, the average 

per capita water use was about 164 gallons per day during 

this wet year. Since a significant portion of urban water is used 

for outdoor landscapes, parks and golf courses, the per capita 

water use is lower than normal during a wet year. Total urban 

ETAW was 64,800 acre-feet.

Total environmental water demand, including instream flows, 

wild and scenic rivers, and refuge water diversions, for the 

region was about 339,000 acre-feet in 1998. This accounted 

for about 24 percent of total developed water uses for this year. 

Within the Central Coast region, most of this environmental 

water is dedicated to the wild and scenic river flow requirements for the Big Sur River and the Sisquoc River. 

Total water supplies for the Central Coast region, including 

local and imported (CVP and SWP) surface water, groundwater, and reuse, amounted to 1.4 million acre-feet. 

Water Year 2000 

The weather and rainfall amounts for water year 2000 in 

the Central Coast region were slightly wetter than normal 

average conditions. Rainfall amounts for representative locations include Santa Cruz with 118 percent of average (36.4 

inches), Salinas at 110 percent of average (16.5 inches), 

Santa Maria at 113 percent of average (14.6 inches) and 

Santa Barbara at 121 percent of average (21.3 inches). For 

the entire hydrologic region, average annual precipitation was 

110 percent of normal, compared to a statewide average of 

97 percent of normal. 

Water storage in the Central Coast watersheds was reported 

as above normal. Average reservoir storage on May 1 was 

115 percent of normal with runoff to May 1 measured at 

105 percent of normal. The land acreage used for irrigated 

agriculture continued the past trend of remaining relatively 

stable. Crop acreage, however, increased 7 percent from 

1998 to 2000 to a total of 605,000 acres. This increase in 

crop acreage is due to expanded use of the practice of growing multiple crops per season on the same piece of land. The 

estimated amount of multiple cropping in 2000 increased 

5 percent and is reflected in the increased acreage of truck 

crops of 7 percent above 1998 amounts. Truck crops comprised about 72 percent of total crop acreage in this region, 

while the next largest crop category, vineyard, comprised 15 

percent of total acreage. 

The year 2000 on-farm agricultural applied water use in the 

Central Coast region was 999,400 acre-feet , while total 

agricultural water use was 1,016,300 acre-feet, or 71 percent 

of all water uses. This amounts to 23 percent more applied 

water than was estimated in 1998 and is considered to be 

more representative of agricultural water use under normal 

hydrologic conditions. Average on-farm unit applied water in 

2000 was 1.7 acre-feet per acre, compared to 1.4 acre-feet 

per acre in 1998. The total agricultural evapotranspiration of 

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Chapter 4 Central Coast Hydrologic Region 4 13

California Water Plan Update 2005

 Applied Net Depletion Applied Net Depletion Applied Net Depletion

Water Use Water Use Water Use Water Use Water Use Water Use

1998 2000 2001

WATER USE

Table 4-2 Central Coast Region Water Use and Distribution of Dedicated Supplies - TAF 

DEDICATED WATER SUPPLIES

Urban

Large Landscape 13.7 10.4 10.3 

Commercial 47.7 52.6 50.0 

Industrial 23.7 24.0 23.7 

Energy Production 14.3 14.3 14.3 

Residential - Interior 101.9 121.2 121.1 

Residential - Exterior 56.3 69.0 70.1 

Evapotranspiration of Applied Water 64.8 64.8 73.3 73.3 74.2 74.2

E&ET and Deep Perc to Salt Sink 24.3 24.3 26.8 26.8 25.8 25.8

Outflow 103.7 103.7 116.7 116.7 113.9 113.9

Conveyance Applied Water 3.9 4.2 4.4 

Conveyance Evaporation & ETAW 3.9 3.9 4.2 4.2 4.4 4.4

Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Outflow 0.0 0.0 0.0 0.0 0.0 0.0

GW Recharge Applied Water 0.0 0.0 0.0 

GW Recharge Evap + Evapotranspiration 0.0 0.0 0.0 0.0 0.0 0.0

 Total Urban Use 261.5 196.7 196.7 295.7 221.0 221.0 293.9 218.3 218.3

 

Agriculture

On-Farm Applied Water 816.3 999.4 1,152.1 

Evapotranspiration of Applied Water 556.9 556.9 681.0 681.0 785.9 785.9

E&ET and Deep Perc to Salt Sink 3.0 3.0 4.2 4.2 4.9 4.9

Outflow 33.6 33.6 45.3 45.3 50.3 50.3

Conveyance Applied Water 12.7 16.9 18.7 

Conveyance Evaporation & ETAW 11.8 11.8 14.7 14.7 16.7 16.7

Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Outflow 0.0 0.0 1.0 1.0 1.0 1.0

GW Recharge Applied Water 0.0 0.0 0.0 

GW Recharge Evap + Evapotranspiration 0.0 0.0 0.0 0.0 0.0 0.0

 Total Agricultural Use 829.0 605.3 605.3 1,016.3 746.2 746.2 1,170.8 858.8 858.8

 

Environmental

Instream

 Applied Water 20.3 21.4 10.8 

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Wild & Scenic

 Applied Water 318.6 103.2 73.9 

 Outflow 173.5 173.5 94.7 94.7 48.5 48.5

Required Delta Outflow

 Applied Water 0.0 0.0 0.0 

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Managed Wetlands

 Habitat Applied Water 0.1 0.1 0.1 

 Evapotranspiration of Applied Water 0.1 0.1 0.1 0.1 0.1 0.1

 E&ET and Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Applied Water 0.0 0.0 0.0 

 Conveyance Evaporation & ETAW 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Total Managed Wetlands Use 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

 Total Environmental Use 339.0 173.6 173.6 124.7 94.8 94.8 84.8 48.6 48.6

 

TOTAL USE AND OUTFLOW 1,429.5 975.6 975.6 1,436.7 1,062.0 1,062.0 1,549.5 1,125.7 1,125.7

 

 

Surface Water

 Local Deliveries 79.2 79.2 79.2 51.1 51.1 51.1 46.0 46.0 46.0

 Local Imported Deliveries 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

 Colorado River Deliveries 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

 CVP Base and Project Deliveries 18.1 18.1 18.1 56.8 56.8 56.8 59.7 59.7 59.7

 Other Federal Deliveries 54.1 54.1 54.1 61.4 61.4 61.4 54.6 54.6 54.6

 SWP Deliveries 24.8 24.8 24.8 30.9 30.9 30.9 28.0 28.0 28.0

 Required Environmental Instream Flow 173.4 173.4 173.4 94.7 94.7 94.7 48.4 48.4 48.4

Groundwater

 Net Withdrawal 608.5 608.5 608.5 749.0 749.0 749.0 870.5 870.5 870.5

 Deep Percolation of Surface and GW 288.5 344.8 387.6 

Reuse/Recycle

 Reuse Surface Water 165.4 29.9 36.2 

 Recycled Water 17.5 17.5 17.5 18.1 18.1 18.1 18.5 18.5 18.5

 

TOTAL SUPPLIES 1,429.5 975.6 975.6 1,436.7 1,062.0 1,062.0 1,549.5 1,125.7 1,125.7

Balance = Use - Supplies 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

 

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4 14 Volume 3 Regional Reports

applied water, or ETAW, in 2000 amounted to 681,000 acrefeet, which was 22 percent greater than 1998. The regional 

average unit ETAW was 1.1 acre-feet per acre. 

Total urban applied water use for the Central Coast region 

was 295,700 acre-feet, which was 13 percent higher than the 

total applied water for 1998. Average per capita water use 

was about 181 gallons per day, which is about 10 percent 

higher than 1998 usage. Urban applied water accounted for 

about 21 percent of the total water use in the region. Total 

population in the region during year 2000 was 1,459,200, 

which is an increase of about 3.6 percent over the 1998 

population. When compared to the 1998 wet year, the above 

increases in urban water use are primarily due to significantly 

less rainfall in year 2000 than in 1998, which means that 

more urban water was needed for outdoor landscape, parks 

and golf courses. Total urban ETAW was 73,300 acre-feet, 

which is 13 percent more than in 1998.

Total environmental water demand (instream, wild and 

scenic, and refuges) for this region in year 2000 was about 

124,700 acre-feet, a significant 63 percent less than 1998. 

This accounted for about 8 percent of total developed and 

dedicated water uses during year 2000. This is water that is 

reserved for instream and wild and scenic river flows, which 

are generally higher in the wetter years (like 1998) and decline 

to lower flow levels in average and drier years. 

Total water supplies, including local and imported (CVP and 

SWP) surface water, groundwater, and reuse, amounted to 

1.4 million acre-feet, about the same as 1998. 

Water Year 2001

The weather and precipitation for water year 2001 in the 

Central Coast Region varied considerably from north to south. 

The total rainfall recorded in Santa Cruz was 82 percent of 

average (25.4 inches), Salinas was at 90 percent of average 

(13.5 inches), King City was at 116 percent of average (12.8 

inches) and Santa Barbara received 146 percent of average 

precipitation (23.5 inches). For the entire hydrologic region, 

average annual precipitation was 107 percent of normal, 

compared to a statewide average of 72 percent. The winter 

season 2001 was characterized by a lack of rainfall across 

the region during October through December.

Surface water runoff in the watersheds of the Central Coast 

region was reported as below average, with accumulated 

runoff to May 1 measured at 70 percent of average amounts. 

However, reservoir storage on May 1 was 135 percent of 

average because of significant storage carryover from the 

previous year. Total cropped acreage in 2001 was 601,900 

acres, which was very similar to year 2000. In 2000, the prices 

of many of the core crops grown in the region had increased 

significantly. However, in 2001, many of these same crops had 

lower production amounts and price declines. Head lettuce, 

broccoli, cauliflower, and celery production all experienced 

decreases in 2001. 

Year 2001 on-farm agricultural applied water use in the Central 

Coast region was 1,152,100 acre-feet, while the total agriculture water use was 1,170,800 acre-feet or 76 percent of all 

water uses. This amounted to 41 percent more agricultural water 

use than 1998 and 15 percent more than 2000. Average onfarm unit applied water use per acre also increased in 2001 to 

1.9 acre-feet per acre compared to 1.4 acre-feet per acre in 

1998 and 1.7 in 2000. As the above data confirms, the need 

for agricultural applied water increases as the amount of winter 

precipitation decreases from 1998 (wet) to 2000 and 2001. The 

total unit ETAW in 2001 was 785,900 acre-feet, which is 41 

percent more than 1998 and 15 percent more than 2000. The 

regional average unit ETAW was 1.3 acre-feet per acre. 

In 2001, total urban applied water for the region was 293,900 

acre-feet, which was about 12 percent more than 1998 and 

1 percent less than year 2000. Average per capita water use 

was around 176 gallons per day. Urban water use accounted 

for about 19 percent of the total water use in the region. Total 

population in the region in 2001 was about 1,476,800, an 

increase of 1.2 percent from the year 2000 population. Total 

urban ETAW was 74,200 acre-feet, 15 percent more than 1998 

and 1 percent more than in year 2000.

Dedicated environmental water use (instream, wild and scenic 

flows, and refuges) for the region dropped to 84,800 acre-feet 

in 2001, 75 percent less than 1998 and 32 percent less than 

2000. This accounts for about 5 percent of total developed water 

uses during this year, and reflects the lower wild and scenic flow 

volumes in the Big Sur River and the Sisquoc River. 

Total available water supplies, including local and imported (CVP 

and SWP) surface water, groundwater, and reuse, amounted to 

1.5 million acre-feet in 2001, which is an 8 percent increase 

from 1998 and 2000. 

Water Portfolio Table 4-3 and the companion Water Portfolio 

flow diagrams (Figures 4-4 and 4-5) provide more information 

about how the available water supplies are distributed and used 

on a region-wide basis.

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California Water Plan Update 2005

Selected References

Water Quality Control Plan, Regional Water Quality 

 Control Board 

Watershed Management Initiative Chapter, Regional Water 

Quality Control Board 

2002 California 305(b) Report on Water Quality, State Water 

Resources Control Board 

Bulletin 118 (Draft), California’s Groundwater, Update 2003, 

Department of Water Resources 

Nonpoint Source Program Strategy and Implementation Plan, 

1998-2013, State Water Resources Control Board, California 

Coastal Commission, January 2000 

Strategic Plan, State Water Resources Control Board, Regional 

Water Quality Control Boards, November 15, 2001 

The Californian, Salinas 

San Luis Obispo County Tribune 

Monterey County Herald 

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4 17 Volume 3 Regional Reports

Water Portfolios

Central Coast Hydrologic Region

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Chapter 4 Central Coast Hydrologic Region

Table 4-3 Central Coast region water portfolios - TAF 

 ID Central Coast Central Coast Central Coast

Number: Flow Diagram Component (see legend) 1998 2000 2001

 1 Colorado River Deliveries - - -

 2 Total Desalination - - -

 3 Water from Refineries - - -

 4a Inflow From Oregon - - -

 b Inflow From Mexico - - -

 5 Precipitation 25,201.6 12,596.4 11,847.9

 6a Runoff - Natural N/A

 b Runoff - Incidental N/A

 7 Total Groundwater Natural Recharge N/A

 8 Groundwater Subsurface Inflow N/A

 9 Local Deliveries 79.2 51.1 46.0

 10 Local Imports - - -

 11a Central Valley Project :: Base Deliveries - - -

 b Central Valley Project :: Project Deliveries 18.1 56.8 59.7

 12 Other Federal Deliveries 54.1 61.4 54.6

 13 State Water Project Deliveries 24.8 30.9 28.0

 14a Water Transfers - Regional - - -

 b Water Transfers - Imported - - -

 15a Releases for Delta Outflow - CVP 

 b Releases for Delta Outflow - SWP 

 c Instream Flow Applied Water 20.3 21.4 10.8

 16 Environmental Water Account Releases - - -

 17a Conveyance Return Flows to Developed Supply - Urban - - -

 b Conveyance Return Flows to Developed Supply - Ag - - -

 c Conveyance Return Flows to Developed Supply - Managed Wetlands - - -

 18a Conveyance Seepage - Urban - - -

 b Conveyance Seepage - Ag - - -

 c Conveyance Seepage - Managed Wetlands - - -

 19a Recycled Water - Agriculture - - -

 b Recycled Water - Urban 17.5 18.1 18.5

 c Recycled Water - Groundwater - - -

 20a Return Flow to Developed Supply - Ag - - -

 b Return Flow to Developed Supply - Wetlands - - -

 c Return Flow to Developed Supply - Urban - - -

 21a Deep Percolation of Applied Water - Ag 210.7 254.0 295.9

 b Deep Percolation of Applied Water - Wetlands - - -

 c Deep Percolation of Applied Water - Urban 76.9 89.6 90.7

 22a Reuse of Return Flows within Region - Ag - - -

 b Reuse of Return Flows within Region - Wetlands, Instream, W&S 165.4 29.9 36.2

 24a Return Flow for Delta Outflow - Ag - - -

 b Return Flow for Delta Outflow - Wetlands, Instream, W&S - - -

 c Return Flow for Delta Outflow - Urban Wastewater - - -

 25 Direct Diversions 

 26 Surface Water in Storage - Beg of Yr 589.1 770.2 778.5

 27 Groundwater Extractions - Banked - - -

 28 Groundwater Extractions - Adjudicated - - -

 29 Groundwater Extractions - Unadjudicated 897.0 1,093.8 1,258.1

 23 Groundwater Subsurface Outflow N/A N/A N/A

 30 Surface Water Storage - End of Yr 990.1 778.5 764.5

 31 Groundwater Recharge-Contract Banking - - -

 32 Groundwater Recharge-Adjudicated Basins - - -

 33 Groundwater Recharge-Unadjudicated Basins - - -

 34a Evaporation and Evapotranspiration from Native Vegetation 

 b Evaporation and Evapotranspiration from Unirrigated Ag 

 35a Evaporation from Lakes 10 11.6 10.9

 b Evaporation from Reservoirs 74.2 75.9 71.5

 36 Ag Effective Precipitation on Irrigated Lands 214 170.6 156.8

 37 Agricultural Water Use 816.3 999.4 1,152.1

 38 Managed Wetlands Water Use 0.1 0.1 0.1

 39a Urban Residential Use - Single Family - Interior 69.3 83.7 87.1

 b Urban Residential Use - Single Family - Exterior 42.9 53.1 54.5

 c Urban Residential Use - Multi-family - Interior 32.6 37.5 34.0

 d Urban Residential Use - Multi-family - Exterior 13.4 15.9 15.6

 40 Urban Commercial Use 47.7 52.6 50.0

 41 Urban Industrial Use 23.7 24.0 23.7

 42 Urban Large Landscape 13.7 10.4 10.3

 43 Urban Energy Production 14.3 14.3 14.3

 44 Instream Flow - - -

 45 Required Delta Outflow - - -

 46 Wild and Scenic Rivers 173.5 94.7 48.5

 47a Evapotranspiration of Applied Water - Ag 556.9 681 785.9

 b Evapotranspiration of Applied Water - Managed Wetlands 0.1 0.1 0.1

 c Evapotranspiration of Applied Water - Urban 64.8 73.3 74.2

 48 Evaporation and Evapotranspiration from Urban Wastewater - - -

 49 Return Flows Evaporation and Evapotranspiration - Ag 3 4.2 4.9

 50 Urban Waste Water Produced 68 79.7 75

 51a Conveyance Evaporation and Evapotranspiration - Urban 11.3 12.7 12.4

 b Conveyance Evaporation and Evapotranspiration - Ag 11.8 14.7 16.7

 c Conveyance Evaporation and Evapotranspiration - Managed Wetlands - - -

 d Conveyance Outflow to Mexico 

 52a Return Flows to Salt Sink - Ag 33.6 46.3 51.3

 b Return Flows to Salt Sink - Urban 120.6 135 131.7

 c Return Flows to Salt Sink - Wetlands - - -

 53 Remaining Natural Runoff - Flows to Salt Sink 173.5 94.7 48.5

 54a Outflow to Nevada - - -

 b Outflow to Oregon - - -

 c Outflow to Mexico - - -

 55 Regional Imports 108.2 149.1 142.3

 56 Regional Exports 65.8 88.9 132.7

 59 Groundwater Net Change in Storage -608.5 -749.0 -870.5

 60 Surface Water Net Change in Storage 401.0 8.3 -14.0

 61 Surface Water Total Available Storage 1,226.8 1,226.8 1,226.8

 

Inflows Outflows Green number signifies included in summary boxes 

EE-RM-PET-100 C0MMENT 01A
Figure 4-4 Central Coast region - illustrated water flow diagram

INFLOWS

SUMMARY

OUTFLOWS

8

15a,b

21

27

31

45

48

51

5

6

46

14 16

33

28

29

32

39- 43

59

50

18

9

51

34

47b

38

35

51

26

30

60

61

11

12

13

15c

54

56

7

1

4

55

10 44

36

47a

49

51

37

17

20

47c

22

25 24

31

23

2

3

52

53

19

In this illustration of Table 4-3, key components of the flow diagram are shown as characteristic elements of the hydrologic cycle. Circled numbers correspond to the identification number of flow diagram components in the table; its color indicates whether the component is water input, output, or summary.

52

Volume 3 Regional Reports Chapter 4 Central Coast Hydrologic Region 4 19

California Water Plan Update 2005

EE-RM-PET-100 C0MMENT 01A
SUMMARY

OUTFLOWS

INFLOWS

Figure 4-5 Central Coast region - schematic flow diagram

In schematic of Table 4-3, key components of the flow diagram are shown as boxes and connectors in a flow chart. Circled numbers correspond to the identification number of flow diagram components in the table; box color indicates whether component is water input, output, or summary. 

Blank boxes are flow diagram components not relevant to the region. 

WILD & SCENIC RIVERS NET 

USE:

RUNOFF:

NATURAL: INCIDENTAL: 

PRECIPITATION: TOTAL STREAM 

FLOW: 

AG EFFECTIVE 

PRECIPITATION ON 

IRRIGATED LANDS: 

LOCAL

DELIVERIES:

CVP PROJECT 

DELIVERIES:

OTHER FEDERAL 

DELIVERIES:

SWP DELIVERIES: 

WATER DEPOSITS: 

SURFACE WATER: 

GROUNDWATER: 

RECYL & DESAL:

TRANSFERS:

TOTAL GROUNDWATER NATURAL RECHARGE: 

GROUNDWATER CHANGE IN STORAGE: 

BANKED:

ADJUDICATED: 

UNADJUDICATED: 

GW EXTRACTIONS:

CONTRACT BANKS:

ADJUDICATED BASINS: 

UNADJUDICATED BASINS: 

EVAPOTRANSPIRATION 

OF APPLIED WATER: 

AG:

WETLANDS:

URBAN:

WATER USE (APPLIED): 

AGRICULTURAL: 

WETLANDS:

URBAN:

RECYCLED WATER: 

AG: URBAN:

GW: 

URBAN

WASTEWATER 

PRODUCED:

INCIDENTAL E & ET 

AG RETURN FLOWS: 

AG & WETLANDS 

RETURN FLOWS:

RETURN FLOWS TO SALT 

SINKS:

AG: WETLANDS:

URBAN:

REMAINING NATURAL 

RUNOFF

FLOW TO SALT SINKS: 

DEEP PERC OF APPLIED 

WATER: 

AG: WETLANDS:

URBAN:

RETURN FLOW TO 

DEVELOPED

SUPPLY: 

AG:

WETLANDS:

URBAN:

EVAP FROM: 

LAKES:

RESERVOIRS:

E & ET FROM:

NATIVE VEGETATION: 

UNIRRIGATED AG: 

RELEASES FOR 

INSTREAM USE: 

CONVEYANCE E&ET, 

RETURN FLOWS, & 

SEEPAGE:

URBAN: AG:

WETLANDS:

CONVEYANCE E & ET: 

URBAN: AG:

WETLANDS:

CONVEYANCE RETURN 

FLOWS:

URBAN: AG:

WETLANDS:

CONVEYANCE SEEPAGE: 

URBAN: AG:

WETLANDS:

RETURN FLOW FOR 

DELTA OUTFLOW: 

AG:

WETLANDS:

URBAN : 

EVAPORATION AND EVAPOTRANSPIRATION OF APPLIED WATER, 

PRECIPITATION AND CONVEYANCE: 

GW RECHARGE:

CONTRACT BANKING:

ADJUDICATED BASINS: 

UNADJUDICATED BASINS: 

TO E & ET: 

SUBSURFACE GW 

INFLOW: 

SUBSURFACE 

GROUNDWATER 

OUTFLOW: 

OTHER REGIONAL 

TRANSFER OUT: 

REGIONAL

TRANSFER IN: 

SURFACE WATER IN 

STORAGE: 

 Beg of Yr: 

End of Yr: 

DIRECT 

DIVERSIONS:

Service Area

Return 

Flow within

Return of

Required Instream 

Flows

Return of

Required Wild & 

Scenic Flows

1

2

5

4

3

55

6

13

11

19

12

10

9

7

20

21

45

29

26

30

35

39 to 43

37

38

53

54

46

14

34 36

28

52

16

24

17

18

25

47

50

49

48

27

31

32

33

23

8

15C

15A

15B

56

44

16

51

22

4 20 Chapter 4 Central Coast Hydrologic Region Volume 3 Regional Reports

California Water Plan Update 2005

EE-RM-PET-100 C0MMENT 01A
Chapter 5 South Coast Hydrologic Region 

Volume 3 

EE-RM-PET-100 C0MMENT 01A
Chapter 5 South Coast Hydrologic Region i5

California Water Plan Update 2005

Chapter 5 South Coast Hydrologic Region

Contents

Chapter 5 South Coast Hydrologic Region ................................................................................................................5-1

Setting ................................ 5-1

Climate ............................... 5-2

Population .......................... 5-2

Land Use ............................ 5-2

Water Supply and Use ......... 5-3

State of the Region .............. 5-9 

 Challenges ..................... 5-9

 Accomplishments .......... 5-12

Looking to the Future ......... 5-16

Water Portfolios for Water Years 1998, 2000, and 2001 .....................................................................................5-19

Selected References ........... 5-19

Box

Box 5-1 Integrated Resource Planning .......................................................................................................................5-1

Box 5-2 Acronyms Used in the South Coast Report ....................................................................................................5-4

Box 5-3 Water Use During Latter Stages of 1987-1992 Drought .................................................................................5-6

Box 5-4 SWRCB Decision 1631 ...............................................................................................................................5-9

Box 5-5 Two Examples of Ongoing Ecosystem Restoration ........................................................................................5-10

Box 5-6 Key Elements of California’s Colorado River Quantification Settlement Agreement .........................................5-12

Figures

Figure 5-1 South Coast Hydrologic Region (map) ......................................................................................................5-ii

Figure 5-2 South Coast Hydrologic Region population ...............................................................................................5-2

Figure 5-3 South Coast region water balance for water years 1998, 2000, 2001 (2 bar charts) ...................................5-5

Figure 5-4 MWD inland feeder ..............................................................................................................................5-13

Figure 5-5 MWD storage agreements with San Joaquin agencies .............................................................................5-15

Figure 5-6 South Coast region - illustrated water flow diagram .................................................................................5-23

Figure 5-7 South Coast region - schematic flow diagram ..........................................................................................5-24

Tables

Table 5-1 South Coast Hydrologic Region water balance summary .............................................................................5-7

Table 5-2 South Coast Hydrologic Region water use and distribution of dedicated supplies ...........................................5-8

Table 5-3 South Coast region water portfolios .........................................................................................................5-22

EE-RM-PET-100 C0MMENT 01A
Volume 3 Regional Reports

California Water Plan Update 2005

VENTURA

LOS ANGELES

ORANGE

RIVERSIDE

SAN DIEGO

Some Statistics

 Area - 110,925 square miles (6.9% of State)

 Average annual precipitation - 17.6 inches

 Year 2000 population - 18,223,425

 2030 population projection - 23,827,075

 Total reservoir storage capacity - 3,059 TAF

 2000 irrigated crop area - 280,260 acres

.

.

.

.

.

.

Flow in TAF

1998

1,081

2000

1,296

2001

1,250

Colorado River Region

Colorado River Aqueduct

Flow in TAF

1998

623

2000

829

2001

381

South Lahontan Region

East Branch California Aqueduct (SWP)

Flow in TAF

1998

663

2000

866

2001

874

South Lahontan Region

Los Angeles Aqueduct

West Branch California Aqueduct (SWP)

Figure 5-1 South Coast Hydrologic Region

The South Coast Hydrologic Region in the southwestern corner of California is the most urbanized and populous region. Arrows indicate annual 

water flows entering and leaving the region for water years 1998, 2000, and 2001. 

Flow in TAF

1998

2,110

2000

2,498

2001

2,325

Outflow to Ocean*

*Outflow to Ocean includes Wild and Scenic Rivers, regulated flows, and estimated wastewater outflows.

EE-RM-PET-100 C0MMENT 01A
Chapter 5 South Coast Hydrologic Region 15

California Water Plan Update 2005

Chapter 5 South Coast Hydrologic Region

Setting

The South Coast Hydrologic Region comprises the southwest 

portion of the state and is California’s most urbanized and 

populous region. It contains slightly more than half of the 

state’s population (54 percent) but covers only 7 percent of 

the state’s total land area. The topography includes a series 

of nearly flat coastal plains and valleys, many broad but 

gentle interior valleys, and several mountain ranges of low 

and moderate elevation. 

The region extends about 250 miles along the Pacific Coast 

from the Ventura-Santa Barbara County line in the north to the 

international border with Mexico in the south (Figure 5-1). The 

region includes all of Orange County and portions of Ventura, 

Los Angeles, San Bernardino, Riverside, and San Diego counties. 

There are several prominent rivers in the region including the 

Sespe, Ventura, Santa Clara, Los Angeles, San Gabriel, Santa 

Ana, San Jacinto, Santa Margarita, San Luis Rey, San Dieguito, Sweetwater, and Otay rivers. Segments of some of these 

rivers have been extensively lined and in other ways modified 

for flood control. Natural runoff of the region’s streams and 

rivers averages about 1.2 million acre-feet annually. 

Within the South Coast Hydrologic Region, water wholesalers 

and retailers, groundwater agencies, and watershed planners 

and managers are becoming increasingly successful in working together to implement a large and diverse array of local 

water supply and water quality projects. In turn, this increased 

level of cooperation and integrated planning is making the 

region more flexible and less dependent on imported water, 

particularly during dry years (see Box 5-1).

This regional profile, after describing the characteristics of the 

region, provides examples of the South Coast’s challenges, 

accomplishments, and plans to meet the water needs of the 

future. There are many more examples of water issues and 

accomplishments than are presented in this chapter. It is 

important to note that in the highly developed South Coast 

region there are now many major water interest groups and 

agencies with important roles to fulfill in providing reliable, 

affordable, high quality water. The jurisdictions and common 

areas of interest for these stakeholder interest groups often 

overlap, such that shared communication and integrated 

regional planning are becoming increasingly important to 

successful water planning and management. 

Box 5-1 Integrated Resource Planning

The Metropolitan Water District of Southern California adopted its Integrated Resource Plan in 1996 and recently has 

revised that plan with the adoption of the 2004 Update. The new 2004 Update accomplishes the three objectives of 

reviewing goals and achievements of the 1996 Integrated Resource Plan, identifying changed conditions for water 

resource development, and updating the resource targets through 2025.

The Santa Ana Water Project Authority recently completed its 2002 Integrated Water Resource Plan. It provides information on water demand and supply planning, water resource plans from member agencies, balancing and integrating 

available resources, and identifying regional problems and issues and potential long-term solutions.

EE-RM-PET-100 C0MMENT 01A
California Water Plan Update 2005

25 Volume 3 Regional Reports

Climate 

The region has a mild, dry subtropical climate where summers are virtually rainless, except in the mountains where late 

summer thunderstorms sometimes occur. About 75 percent of 

the region’s precipitation falls from December through March. 

The coastal plains and the interior valleys receive on average 12 to 18 inches of annual precipitation, depending on 

location, but the climate allows for a much wider variation 

from year to year. Much of the 20 to 40 inches of annual 

average precipitation in the higher mountains falls as snow. 

Population

The region’s 2000 population was 18,223,000. The fastest 

growing portion of the South Coast region is that known 

as the Inland Empire, which includes the inland valleys of 

Riverside and San Bernardino counties. The region contains 

seven of the state’s fastest-growing cities, in terms of percentage change in growth (Temecula, Chula Vista, Irvine, 

Riverside, Fontana, Rancho Cucamonga, and Murietta). The 

city of Los Angeles is the state’s biggest city. Its population 

grew from 3,486,000 in 1990 to 3,645,000 in 2000. The 

population in San Diego County is concentrated along the 

coastal terraces and valleys, and south of CampPendleton, 

the U.S. Marine base. In 2000, the city of San Diego was 

America’s seventh largest city, and California’s second largest, with 1,223,000 persons. Figure 5-2 provides a graphical 

depiction of the South Coast region’s total population from 

1960 through 2000, with current projections to year 2030. 

Land Use

The mild climate and ample expanse of gentle landscapes in 

the South Coast region have encouraged a variety of land uses 

since the first great development boom of the late 1880s. The 

expansion of new single- and multi-family homes, commercial 

services, businesses, and highway systems into the warmer 

The South Coast region comprises the southwest portion of the state and is California’s most urbanized and populous region. The photo depicts the Los 

Angeles skyline. (DWR Photo)

EE-RM-PET-100 C0MMENT 01A
Chapter 5 South Coast Hydrologic Region 35

California Water Plan Update 2005

sections of the region continues onto lands that were historically 

pastoral, if not agricultural. Although pockets of open space 

and agricultural uses still exist, the urban area now extends 

southward from Ventura County to the international border 

with Mexico and eastward from the coast to beyond Riverside 

and San Bernardino. Irrigated agriculture now occupies only 

one-seventh as much land as urban uses. Environmental water 

uses are mostly limited to relatively small, managed wetland 

areas, wildlife areas, lakes, and riparian habitats.

Although the acreage has continued to decline in recent years, 

agriculture is still economically important for the region. In 

2000, the total value of agricultural products in San Diego 

County was $1.3 billion. The total crop acreage in year 

2000 was about 280,000 acres, which produced a variety of 

crops that included high-valued citrus and subtropical fruits, 

fresh-market vegetable crops, and assorted nursery products. 

Although agricultural uses occur throughout the region, the 

major areas continue to be the Oxnard Plain (for vegetables) 

and the adjacent hills and valleys (for citrus and subtropical 

fruits) in Ventura County; the coastal (for nursery) and interior 

valleys (for citrus and avocado fruits) in San Diego County; 

and the Chino area (for dairies) in San Bernardino County.

Water Supply and Use

The region has developed a diverse mix of both local and 

imported water supply sources. Local water resources development over the last 15 years has included water recycling, 

groundwater storage and conjunctive use, conservation, 

brackish water desalination, water transfer and storage, and 

infrastructure enhancements to complement imported water 

supplies. The region imports water through the State Water 

Project (SWP), the Colorado River Aqueduct (CRA), and the 

Los Angeles Aqueduct (LAA) (see Box 5-2 for acronyms used 

in this report). This diverse mix of sources provides fl exibility 

in managing supplies and resources in wet and dry years. 

Figure 5-3 provides a graphical presentation of all of the 

water supply sources that are used to meet the developed 

water uses within this hydrologic region for 1998, 2000, and 

2001. Figure 5-3 also presents a bar chart that summarizes 

all of the dedicated and developed urban, agricultural and 

environmental water uses within this hydrologic region for 

1998, 2000 and 2001.

The Metropolitan Water District of Southern California (MWD) 

imported an average of 703,000 acre-feet per year of water 

from the SWP from 1972 to 2003 (the contracted amount is 

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

1960 1970 1980 1990 2000 2010 2020 2030

Figure 5-2 South Coast Hydrologic Region population

Data from California Department of Finance provide decadal population from 1960 to 2000 and population projection for 2030 

for the South Coast region.

EE-RM-PET-100 C0MMENT 01A
California Water Plan Update 2005

45 Volume 3 Regional Reports

currently 1,811,000 acre-feet per year; actual imports have 

been closer to this amount for the last few years), and 680,000 

acre-feet or more of water from the CRA (depending on the 

availability of surplus water). MWD wholesales the water to a 

consortium of 26 cities, water districts, and a county authority 

that serve 18 million people living in six counties stretching 

from Ventura to San Diego. 

Fifteen percent of the region’s water supply is developed by 

water agencies located outside of the service area of MWD 

and its members agencies. These agencies also import water 

from the SWP, or use local supplies, usually groundwater. 

Agencies that import SWP water include Castaic Lake Water 

Agency, San Bernardino Valley Municipal Water District 

(SBVMWD), Ventura County Flood Control District, San 

Gorgonio Pass Water Agency, and the San Gabriel Valley 

Municipal Water District. 

Groundwater and groundwater agencies are important to the 

water supply picture of the region, meeting about 23 percent 

of water demand in normal years and about 29 percent 

in drought years (see Box 5-3). There are 56 groundwater 

basins in the region. In some California groundwater basins, 

as the demand for groundwater exceeded supply, landowners and other parties turned to the courts to determine how 

much groundwater can rightfully be extracted by each user. 

In a process known as court adjudication, the courts study 

available data to arrive at a distribution of groundwater that 

is available each year, usually based on the California law of 

overlying use and appropriation. There are 19 court adjudications for groundwater basins in California, mostly in Southern 

California. In 15 of these adjudications, the court judgment 

limits the amount of groundwater that can be extracted by all 

parties based on a court-determined safe yield of the basin. 

The basin boundaries are also defined by the court.

Most basin adjudications have resulted in either a reduction 

or no increase in the amount of groundwater extracted. As a 

result, agencies often import surface water to meet increased 

demand. The original court decisions provided watermasters 

with the authority to regulate extraction of the quantity of 

groundwater; however, they omitted authority to regulate 

extraction to protect water quality or to prevent the spread of 

contaminants in the groundwater. Because water quantity and 

water quality are inseparable, watermasters are recognizing 

that they must also manage groundwater quality. 

The use of recycled water, which brings wastewater agencies 

into partnerships with surface and groundwater managers, is 

playing an increasingly significant role in meeting the region’s 

water needs. The best recent data is from the 2002 Statewide 

Recycled Water Survey by the State Water Resources Control 

Box 5-2 Acronyms Used in the South Coast Regional Report

CBDA California Bay-Delta Authority

CRA Colorado River Aqueduct

CVWD Coachella Valley Water District

DBPs disinfection byproducts

DWR California Department of Water Resources

IID Imperial Irrigation District

LAA Los Angeles Aqueduct

LACDPW Los Angeles County Department of 

Public Works

LADWP Los Angeles Department of Water and 

Power

mgd million gallons per day

MTBE methyl tertiary butyl ether 

MWA The Mojave Water Agency

MWD The Metropolitan Water District 

of Southern California

NDMA nitrosodimethylamine

OCWD Orange County Water District

QSA Quantification Settlement Agreement

RWQCB Regional Water Quality Control Board

SAWPA Santa Ana Water Project Authority 

SBVMWD San Bernardino Valley Municipal Water 

District

SCCWRRS Southern California Comprehensive Water 

Reclamation and Reuse Study

SWRCB State Water Resources Control Board

SDCWA San Diego County Water Authority

SWP State Water Project

TDS total dissolved solids

USBR United States Bureau of Reclamation

VOCs volatile organic compounds

WBMWD West Basin Municipal Water District

EE-RM-PET-100 C0MMENT 01A
Chapter 5 South Coast Hydrologic Region 55

California Water Plan Update 2005

Figure 5-3 South Coast region water balance for water years 1998, 2000, 2001

0

1,000

2,000

3,000

4,000

5,000

6,000

1998 2000 2001

Thousand Acre-Feet

Wild & Scenic

R.

Instream Flow

Managed

Wetlands

Irrigated

Agriculture

Urban

0

1,000

2,000

3,000

4,000

5,000

6,000

1998 2000 2001

Thousand Acre-Feet

Reuse &

Recycle

Ground Water

State Project

Federal

Projects

Colorado

Project

Local Projects

Dedicated Water Supplies

Applied Water Uses

Three years show a marked change in the amount and relative proportions of water delivered to South Coast region’s urban and agricultural 

sectors and water dedicated to the environment (applied water, top chart), where the water came from, and how much water was reused 

among sectors (dedicated water supplies, bottom chart).

EE-RM-PET-100 C0MMENT 01A
California Water Plan Update 2005

65 Volume 3 Regional Reports

Board (SWRCB), which estimated that recycled municipal 

water delivery was about 275,000 acre-feet per year in 

Southern California. According to the MWD’s 2003 Annual 

Progress Report, about 204,000 acre-feet of recycled water 

was developed within its service area in fiscal year 2003. By 

the year 2010, MWD expects that its service area will produce 

about 410,000 acre-feet of water through water recycling, 

groundwater recovery, or seawater desalination. 

West Basin Municipal Water District (WBMWD), the largest 

water recycler in the region, has developed more than 31,000 

acre-feet of recycled water. Within the San Diego County 

Water Authority (SDCWA) service area there is roughly 

13,000 acre-feet per year of incidental groundwater recharge 

resulting from wastewater disposal operations, of which 95 

percent is used for agriculture and landscape irrigation.

Water use efficiency measures, which are partnering wastewater treatment agencies with wholesale and retail water 

districts, will continue to have important impacts on the region’s 

supplies and demands. A combination of active and passive 

measures has contributed to decreases in urban demands in 

the region. Recent examples of active water use efficiency 

programs include the installation of ultra-low-flush toilets and 

other water efficient appliances for residential, industrial, and 

institutional uses and the promotion of water efficient landscaping and irrigation. Even greater water supply savings are 

being achieved from passive water use efficiency measures. 

Passive water measures involve changes in the water code that 

require manufacturers to offer customers water-saving devices. 

MWD reports that its member agencies have urban programs 

that conserve about 65,000 acre-feet annually through active 

programs, and inclusion of passive conservation measures 

would make the total savings much larger. 

About 15 percent of the South Coast region’s developed 

water is used for agricultural activities. The sources of water 

supplies that are available for irrigation operations differ 

throughout the region. Groundwater is the primary source 

of water for the agricultural activities on the coastal plain of 

Ventura County. In the middle segment of the region, combinations of groundwater and imported water are used. In 

the southern portion, primarily San Diego County, imported 

water supplies and a small amount of local surface water are 

the primary sources. 

MWD initiated several agricultural water conservation and 

transfer programs, including a program with the Imperial Irrigation District (IID) that conserved 105,130 acre-feet in 2003 

and a crop rotation and water supply program with Palo Verde 

Irrigation District that saved about 186,000 acre-feet of water 

from 1992 through 1994. In addition, SDCWA is in the initial 

stage of an agreement with IID in which IID delivers conserved 

water to SDCWA. SDCWA received 10,000 acre-feet in 2003 

and 20,000 acre-feet in 2004. Thirty thousand acre-feet will 

be delivered in 2005, and deliveries will increase annually 

toward 200,000 acre-feet of conserved water by 2021. 

In the major agricultural areas in the region, most on-farm 

irrigation operations remain very efficient. Farmers are continuing to use the latest equipment to handle crop irrigations 

and conserve water. Micro-jet sprinklers and drip emitters are 

being used for the irrigation operations of most citrus and 

subtropical fruit orchards in San Diego and Ventura counties. Although furrow systems are still in use, drip irrigation 

systems are also used to irrigate the fresh market vegetables 

produced in Ventura County.

The regional water balance table (Table 5-1) provides a detailed 

accounting for all of the water that enters and leaves the South 

Coast region. As shown in the table, the nonquantifiable water 

uses (Evaporation, Evapotranspiration of Native Vegetation, 

Groundwater Subsurface Outflows, etc.) are about the same 

as total precipitation, and outflows to the ocean are relatively 

small. Imports are a large part of the applied water in the 

region. For comparison, Table 5-2 presents information on 

Box 5-3 Water Use During Latter Stages of 1987-1992 Drought

During the latter stages of the 1987-1992 drought and for several years afterward, water supply deliveries and 

municipal and industrial uses for many retail water districts in the South Coast Hydrologic Region were slightly less 

than in the late 1980s. The City of Los Angeles, exemplifies this trend. For water year 1990, the city used 677.1 

thousand acre-feet (taf) of water from various supplies. In 1998 and 2000, the totals were 596.7 taf and 679.5 taf, 

respectively. The increase in water supplies in 2000 was less than 1 percent over the 1990 quantities despite a net 

increase in the population served of more than 400,000.

EE-RM-PET-100 C0MMENT 01A
Chapter 5 South Coast Hydrologic Region 75

California Water Plan Update 2005

Water Entering the Region 

 Precipitation 20,873 7,522 9,327

 Inflow from Oregon/Mexico 0 0 0

 Inflow from Colorado River 1,081 1,296 1,250

 Imports from Other Regions 1,286 1,695 1,255

Total 23,240 10,513 11,832

Water Leaving the Region 

Consumptive Use of Applied Water *

 (Ag, M&I, Wetlands) 1,468 1,819 1,628

 Outflow to Oregon/Nevada/Mexico 0 0 0

 Exports to Other Regions 0 0 0

 Statutory Required Outflow to Salt Sink 0 0 0

 Additional Outflow to Salt Sink 2,110 2,498 2,325

 Evaporation, Evapotranspiration of Native 

 Vegetation, Groundwater Subsurface Outflows, 20,514 7,441 8,947

 Natural and Incidental Runoff, Ag Effective 

 Precipitation & Other Outflows 

Total 24,092 11,758 12,900

Storage Changes in the Region

 [+] Water added to storage

 [−] Water removed from storage 

 Change in Surface Reservoir Storage 372 128 332

 Change in Groundwater Storage ** -1,224 -1,373 -1,400

Total -852 -1,245 -1,068

Applied Water * (compare with Consumptive Use) 4,184 5,041 4,633

*Footnote for applied water

Consumptive use is the amount of applied water used and no longer available as a source of supply. Applied water is 

 greater than consumptive use because it includes consumptive use, reuse, and outflows. 

**Footnote for change in Groundwater Storage

Change in Groundwater Storage is based upon best available information. Basins in the north part of the 

state (North Coast, San Francisco, Sacramento River and North Lahontan regions and parts of Central 

 Coast and San Joaquin River regions) have been modeled – spring 1997 to spring 1998 for the 1998 

 water year and spring 1999 to spring 2000 for the 2000 water year. All other regions and year 2001 were 

 calculated using the following equation: 

GW change in storage =

 intentional recharge + deep percolation of applied water + conveyance deep percolation - withdrawals

This equation does not include the unknown factors such as natural recharge and subsurface inflow and outflow.

 Water Year (Percent of Normal Precipitation) 

1998 (205%) 2000 (72%) 2001 (92%)

Table 5-1 South Coast Hydrologic Region Water Balance Summary - TAF

Water Entering the Region – Water Leaving the Region = Storage Changes in Region

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Table 5-2 South Coast Hydrologic Region water use and distribution of dedicated supplies - TAF

 Applied Net Depletion Applied Net Depletion Applied Net Depletion

Water Use Water Use Water Use Water Use Water Use Water Use

1998 2000 2001

WATER USE

DEDICATED WATER SUPPLIES

Urban

Large Landscape 165.7 242.8 187.5 

Commercial 699.5 914.1 885.5 

Industrial 186.0 209.8 209.8 

Energy Production 39.8 39.8 39.8 

Residential - Interior 1,593.9 1,795.9 1,654.3 

Residential - Exterior 776.1 891.8 860.0 

Evapotranspiration of Applied Water 941.8 941.8 1,134.6 1,134.6 1,047.5 1,047.5

E&ET and Deep Perc to Salt Sink 518.1 518.1 594.5 594.5 570.1 570.1

Outflow 1,678.1 1,678.1 1,976.7 1,976.7 1,850.2 1,850.2

Conveyance Applied Water 160.0 154.6 153.0 

Conveyance Evaporation & ETAW 160.0 160.0 154.6 154.6 153.0 153.0

Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Outflow 0.0 0.0 0.0 0.0 0.0 0.0

GW Recharge Applied Water 0.0 0.0 0.0 

GW Recharge Evap + Evapotranspiration 0.0 0.0 0.0 0.0 0.0 0.0

 Total Urban Use 3,621.0 3,298.0 3,298.0 4,248.8 3,860.4 3,860.4 3,989.9 3,620.8 3,620.8

Agriculture

On-Farm Applied Water 691.9 908.4 758.4 

Evapotranspiration of Applied Water 494.8 494.8 645.8 645.8 542.9 542.9

E&ET and Deep Perc to Salt Sink 11.2 11.2 15.0 15.0 12.3 12.3

Outflow 100.1 100.1 135.1 135.1 110.1 110.1

Conveyance Applied Water 0.0 0.0 0.0 

Conveyance Evaporation & ETAW 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Outflow 0.0 0.0 0.0 0.0 0.0 0.0

GW Recharge Applied Water 0.0 0.0 0.0 

GW Recharge Evap + Evapotranspiration 0.0 0.0 0.0 0.0 0.0 0.0

 Total Agricultural Use 691.9 606.1 606.1 908.4 795.9 795.9 758.4 665.3 665.3

Environmental

Instream

 Applied Water 3.5 3.5 3.5 

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Wild & Scenic

 Applied Water 284.2 34.3 108.2 

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Required Delta Outflow

 Applied Water 0.0 0.0 0.0 

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Managed Wetlands

 Habitat Applied Water 31.2 38.1 37.2 

 Evapotranspiration of Applied Water 31.2 31.2 38.1 38.1 37.2 37.2

 E&ET and Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

 Outflow 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Applied Water 0.0 0.0 0.0 

 Conveyance Evaporation & ETAW 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Outflow 0.0 0.0 0.0 0.0 0.0 0.0

Total Managed Wetlands Use 31.2 31.2 31.2 38.1 38.1 38.1 37.2 37.2 37.2

 Total Environmental Use 318.9 31.2 31.2 75.9 38.1 38.1 148.9 37.2 37.2

 

 TOTAL USE AND OUTFLOW 4,631.8 3,935.3 3,935.3 5,233.1 4,694.4 4,694.4 4,897.2 4,323.3 4,323.3

 

Surface Water

 Local Deliveries 292.1 292.1 292.1 211.4 211.4 211.4 217.1 217.1 217.1

 Local Imported Deliveries 442.0 442.0 442.0 294.0 294.0 294.0 272.0 272.0 272.0

 Colorado River Deliveries 1,081.3 1,081.3 1,081.3 1,296.0 1,296.0 1,296.0 1,250.5 1,250.5 1,250.5

 CVP Base and Project Deliveries 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

 Other Federal Deliveries 4.2 4.2 4.2 0.6 0.6 0.6 0.0 0.0 0.0

 SWP Deliveries 687.7 687.7 687.7 1,300.1 1,300.1 1,300.1 958.7 958.7 958.7

 Required Environmental Instream Flow 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Groundwater

 Net Withdrawal 1,223.5 1,223.5 1,223.5 1,372.5 1,372.5 1,372.5 1,400.0 1,400.0 1,400.0

 Deep Percolation of Surface and GW 408.8 500.9 462.2 

Reuse/Recycle

 Reuse Surface Water 287.7 37.8 111.7 

 Recycled Water 204.5 204.5 204.5 219.8 219.8 219.8 225.0 225.0 225.0

 TOTAL SUPPLIES 4,631.8 3,935.3 3,935.3 5,233.1 4,694.4 4,694.4 4,897.2 4,323.3 4,323.3

Balance = Use - Supplies 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

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the developed and dedicated components of the total supply, 

which is a summary of water that is actively stored, managed 

and used for urban, agricultural and environmental purposes. 

State of the Region

Over the past decade, the region has improved water supply 

reliability in the face of reduced imported supplies from the 

Owens Valley and Mono Basin and reduced uncertainty 

regarding the amount of imports available from the SWP (see 

Box 5-4). Water agencies have been proactive in continuous 

planning to manage the changing water supply and demand 

conditions in the region. While dependent on imported water 

for at least 50 percent of its water supplies, the region’s water 

agencies have compiled a wide range of water management 

tools and water planning practices designed to improve and 

optimize local water resources in relation to the imported 

water needs. 

Challenges

Like many regions in the state, water quality and water supply 

challenges are intertwined. The South Coast region must 

manage for uncertainties caused by population and economic 

growth. Growth will not only affect demand, but it will add 

contamination challenges from increases in wastewater discharges and urban runoff, as well as increased demand for 

water-based recreation. Outside the region, environmental 

and water quality needs in the Delta and Owens River/Mono 

Basin systems affect imported water supply reliability and 

quality. The region must also assess and plan for impacts of 

climate variations and global climate change, as well as the 

cost of replacing aging infrastructure.

Given the size of the region and the diverse sources of 

water supply, the challenges to the region’s water quality are 

varied. Surface water quality issues in the South Coast are 

dominated by storm water and urban runoff, which contribute 

contaminants (including trash) to local creeks and rivers. These 

pollutant sources, as well as sanitary sewer overflows, ocean 

outfalls, tidal input, and even wildlife, can degrade coastal 

water quality, closing beaches and increasing the health risks 

from swimming. These sources also specifically affect water 

quality in the major bays—Santa Monica, Newport, and San 

Diego. Newport Bay, for instance, suffers from algal blooms 

(due to excess nutrients), toxicity to aquatic life, high bacterial 

counts, and sedimentation. Shipping can also influence water 

quality, especially at the U.S. Navy base in San Diego Bay 

and the Long Beach and Los Angeles harbors, where there are 

toxic sediment hot spots. Harbors, marinas, and recreational 

boating threaten water quality via ballast water discharges, 

which can introduce invasive species, petroleum and sewage 

discharges and spills, biocides from boat hulls, boat cleaning and fish wastes, trash, and reduced water circulation. 

The South Coast Wetlands Recovery Project works to restore 

wetland habitat and eradicate exotic species in many watersheds of the region. Several dedicated wildlife and ecological 

reserves are located along the South Coast as well.

Constructed wetland projects in Hemet/San Jacinto, San 

Diego Creek, and Prado Basin remove large loads of nitrogen 

from wastewater and urban runoff. Salinity, nitrogen, and 

microbes are the major contaminants in the Santa Ana River, 

affecting downstream beneficial uses such as swimming and 

groundwater recharge for domestic use. Because of upstream 

irrigation diversions, flows in the middle and lower Santa 

Ana River are composed mostly of recycled water, creating a 

year-round flow that is high in salinity. The Santa Ana River 

suffers as well from an invasive exotic species, the giant reed 

Arundo donax. Other nonnative, invasive species of concern 

in this region include the marine alga Caulerpa taxifolia 

along the San Diego coast, and salt cedar (Tamarix sp.) in 

various streams and rivers; both, like Arundo donax, have the 

potential to wreak havoc with native ecosystems (see Box 5-5). 

Box 5-4 SWRCB Decision 1631

In 1994, State Water Resources Control Board adopted Water Right Decision 1631 amending the City of Los Angeles’ water rights for diverting water from the Mono Basin. The decision restricts diversions from the basin in order to 

increase and maintain Mono Lake’s level to 6,391 feet above sea level. During the period of Mono Lake’s transition 

to the 6,391-foot level (estimated to take about 20 years), the maximum amount of water that Los Angeles can divert 

from the basin is 16 thousand acre-feet per year. Long-term Los Angeles diversions from the Mono Basin are projected 

to be about 31 thousand acre-feet per year after Mono Lake has reached the 6,391-foot level, or one-third of the city’s 

historical diversions from the Mono Basin.

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Lake Elsinore, the largest natural freshwater lake in southern 

California, experiences nuisance algae blooms from excess 

nutrients, impairing its ecological and recreational beneficial 

uses. Local groups have implemented many wetland and river 

restoration projects to improve water quality, for example, at 

Bolsa Chica and in Ballona Creek, as well as along the Los 

Angeles and San Gabriel rivers. The United States and Mexico 

jointly built the International Wastewater Treatment Plant to 

treat a portion of the sewage from Tijuana, which flows across 

the international boundary into the San Diego Basin. 

The Chino Basin hosts the highest concentration of dairy animals in the United States. In a 40 square-mile area, well over 

300,000 animals are maintained on about 300 dairies. Because 

of a lack of sufficient land to dispose of manure, as well as 

flooding from expanding suburban development, dairy runoff 

contributes nitrate, salts, and microorganisms to groundwater 

as well as surface water. Since 1972, the Santa Ana Regional 

Water Quality Control Board (RWQCB) has issued waste discharge requirements to the dairies in this basin. In addition, pilot 

projects to develop sewer systems for dairies and for treating 

dairy wash water have also recently been completed. Water 

utilities can use desalters to recover groundwater from brackish 

aquifers such as the Chino Basin, but only if they have access 

to a regional brine line (the Santa Ana River Interceptor in this 

area). Groundwater quality in this basin is integrally related to 

the surface water quality downstream in the Santa Ana River, 

which in turn serves as a source for groundwater recharge in 

Orange County. Orange County Water District and to the north 

West Basin Municipal Water District operate groundwater injection programs to form hydraulic barriers, to protect aquifers 

from seawater intrusion. 

Public health and environmental and economic concerns have 

grown with the expansion of water recycling programs in the 

South Coast region. Some concerns are related to the total 

dissolved solids (TDS) content of wastewater and the presence 

in treated wastewater of pharmaceuticals, household products, and other emerging contaminants. The high salinity of 

imported Colorado River water limits the number of times water 

can be reused before the salt content becomes too high and 

wastewater can only be discharged to the ocean. Increased 

use of recycled water and marginal quality groundwater 

supplies during droughts can result in water quality problems 

for some local supplies that endanger future water management projects. For instance, groundwater recharge potential 

may be restricted because the RWQCB has established TDS 

requirements for recharge water in some groundwater basins 

in order to protect existing basin water quality.

The average TDS concentration of MWD’s CRA water is about 

600 to 700 mg/L, and the average TDS content of SWP supplies is about 300 mg/L. The water supply from the LAA has 

a significantly lower TDS concentration, typically about 160 

mg/L. TDS levels in local groundwater supplies in the region 

vary considerably, ranging from 200 mg/L (Cucamonga 

Basin near Upland) to more than 1,000 mg/L (Arlington Basin 

near Corona). Local water uses also contribute significantly to 

overall salinity levels. For example, municipal and industrial 

use of water adds between 250 and 500 mg/L of TDS to 

wastewater. Key sources of local salts include water softeners 

(typically contributing from 5 to 10 percent of the salt load) 

and industrial processes. 

The long-term salt balance of the region’s groundwater basins 

is an increasingly critical management issue. Smaller basins 

like the Arlington and Mission groundwater basins were abandoned as municipal supplies because of high salinity levels. 

Some of these basins have only recently been restored through 

brackish water desalting projects. The Mission Basin has not 

been restored, but water is being recovered and treated to 

drinking water standards by the City of Oceanside’s Mission 

Basin Groundwater Repurification Facility. Blending SWP and 

CRA supplies, or using the SWP’s relatively low TDS supplies 

for groundwater replenishment, is a strategy in some areas. 

However, some inland water districts that use recycled water 

Box 5-5 Two Examples of Ongoing Ecosystem Restoration

The Matilija Dam Ecosystem Restoration Feasibility Study evaluated alternatives and has provided a draft recommendation for removing the 160-foot high dam, including stored sediment, to restore the Ventura River ecosystem. The 

Public Draft Report was released in July 2004.

The Santa Ana River Trail and Parkway Project includes planning of recreational uses that showcase the river and 

provide a place for people to enjoy this important resource.

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have salt accumulation problems in their groundwater basins 

because they lack an ocean outfall or stream discharge. To 

dispose of these salts, some districts have developed access 

to a brine pipeline that exports salt and concentrated wastes 

to a coastal treatment plant and ocean outfall. However, there 

are situations where agencies have not constructed a brine 

pipeline due to the high cost of this alternative. 

Beyond salinity, several established and emerging contaminants of concern to the region’s drinking water supplies 

include disinfection byproducts (DBPs), perchlorate, arsenic, 

nitrosodimethylamine (NDMA), hexavalent chromium, and 

methyl tertiary butyl ether (MTBE). Historically, industrial solvents have extensively impacted the groundwater underlying 

the San Gabriel Valley. Imported water from the Owens Valley 

is of excellent water quality, and imported Delta water quality 

is generally good. Nonetheless, arsenic is a concern in the 

Owens Valley supply, and Delta water can contain precursors 

(such as organic carbon and bromide) of potentially carcinogenic DBPs, if treated with certain disinfection processes 

necessary to inactivate pathogens in drinking water.

Perchlorate, a component of rocket fuel that can disrupt thyroid 

gland function, has particularly impacted the groundwater in 

Pasadena and the Rialto-Colton-Fontana region. Perchlorate is 

also a concern in Colorado River water, largely due to contamination from inactive ammonium perchlorate manufacturing 

facilities in Nevada. Perchlorate contamination of wells in the 

San Gabriel Valley, which resulted in the deactivation of many 

of these wells, has led to testing of ion exchange technologies 

for the removal of this constituent. 

Naturally occurring arsenic, a known human carcinogen, is 

another contaminant of concern, present in the LAA supply 

as well as local aquifers. The City of Los Angeles currently 

manages arsenic concentrations in the LAA water through 

treatment. In Southern California, local water sources with 

high arsenic levels are found in Los Angeles, San Bernardino, 

and Riverside counties.

NDMA, a probable human carcinogen, is associated with the 

production of rocket fuel and the manufacture of explosives, 

paints, and other industrial goods. Contamination of surface 

water and groundwater by NDMA at missile and rocket fuel 

manufacturing and storage sites is a significant concern, 

particularly for groundwater supplies. NDMA can also be 

formed during the treatment of wastewater, which is a threat 

to aquifers that are recharged with reclaimed wastewater and 

later used for drinking water. 

Groundwater contamination by hexavalent chromium, a 

suspect carcinogen better known as chromium 6, in the Los 

Angeles basin and elsewhere, has resulted from its use in various industries including aerospace and plating. In Los Angeles 

County, Los Angeles RWQCB staff is overseeing the ongoing 

assessment and cleanup of sites impacted by hexavalent 

chromium at defense-related businesses and manufacturing 

and other industrial sites. 

MTBE and other oxygenates have been added to gasoline 

in areas with severe air pollution to help gasoline burn more 

cleanly and comply with federal law. Unfortunately, MTBE can 

also contaminate groundwater supplies when pipelines, fuel 

tanks, and other containers or equipment leak, when fuel is 

spilled, and when unburned fuel is discharged from watercraft. 

The high mobility and low biodegradability of MTBE present 

a significant risk to aquifer supplies. MTBE has been widely 

detected in South Coast groundwater, surface water, and 

imported water supplies. In particular, MTBE contamination 

forced the closure of more than half of Santa Monica’s water 

supply wells and made the city more dependent upon imported 

water supplies and treatment systems. California has recently 

phased out MTBE from its gasoline supplies. As of January 1, 

2004, California refineries no longer blend MTBE into gasoline. Ethanol is now used as the primary oxygenate in areas 

requiring oxygenate additives under federal law. 

The 198-foot-high Matilija Dam in Ventura County has lost 

most of its water supply and flood control benefits due to sediment deposits. Originally built in 1947 to store up to 7,018 

acre-feet of water, siltation has reduced its effective storage 

capacity to about 500 acre-feet. Moreover, the Matilija Dam 

has had adverse effects on the ecosystem of the Ventura River 

watershed, which supports several threatened and endangered 

species. The structure blocks riparian and wildlife corridors 

between the Ventura River and Matilija Creek. By trapping 

sediment that would otherwise be carried downstream, the 

dam also contributes to the long-term erosion of estuaries and 

beaches along the Ventura River. 

The Matilija Dam Ecosystem Restoration Feasibility Study, a 

joint study by the Ventura County Watershed Protection District 

and the U.S. Army Corps of Engineers, is one of the largest 

dam removal studies ever undertaken in the United States. 

The study recommended the dam’s removal in its July 2004 

public draft report and environmental impact statement/environmental impact report. However, there are disputes over 

rights to the remaining water supply. The Casitas Municipal 

Water District, which leases the dam, pipeline, and rights to 

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the dam’s water from the Ventura County Watershed Protection District, is concerned with how this lost water supply to 

Casitas will be recovered once the Matilija Dam and reservoir 

are removed. Studies and discussions are continuing in order 

to develop solutions for the water supply impacts that could 

result from removal of this dam.

California’s use of Colorado River water is being managed to 

ensure that the state reduces the use of this water from a high 

of 5.3 million acre-feet in previous years to its 4.4 million acrefeet annual apportionment. Until 2016, California may receive 

interim surplus water from the river depending on the storage 

level in Lake Mead. The Colorado River Board of California 

developed the basic plan, called California’s Colorado River 

Water Use Plan or the “4.4 Plan,” that outlines steps to reduce 

the state’s use of Colorado River water. Those steps include a 

water transfer of conserved water from IID to SDCWA, the lining 

of the All-American and Coachella Canals, water storage and 

conjunctive use programs, water exchanges, improved reservoir 

management, salinity control, watershed protection, water 

reuse, and other measures. The signing of the Quantification 

Settlement Agreement (QSA) in 2003 enabled implementation 

of the 4.4 Plan (see Box 5-6).

Drought is a constant concern for water districts in the region. 

This has led to an emphasis on the development of local supplies and demand management strategies. Today, about 50 

percent of Southern California’s demand is being met through 

such local supplies as water conservation, recycling, and 

groundwater recovery. The uncertainty caused by scientific 

findings on climate change also has caused water agencies 

to question the reliability of imported sources. 

Groundwater overdraft and lower groundwater levels are 

challenges to the region. Historically, agricultural, industrial, 

and urban development has led to increased groundwater pumping from many of the region’s basins. In some 

basins over-extraction of groundwater has caused seawater 

intrusion, contributed to land subsidence, and resulted in 

legal disputes over pumping rights within specific basins. 

Accomplishments 

The region has developed a diverse water portfolio that is 

balanced between local and imported supplies. The primary 

objectives of the region’s water agencies are to provide high 

quality, reliable, and affordable water. To achieve these objectives, local water districts have built additional facilities to 

increase surface storage and water transmission capacities. 

They have also implemented a variety of resource management 

strategies to increase the efficiencies of agricultural and urban 

water uses, utilize recycled water, groundwater conjunctive 

use, groundwater remediation, brackish water desalination, 

drinking water treatment, watershed management, groundwater banking, and water transfers from outside the region. 

Box 5-6 Key Elements of California’s Colorado River Quantification Settlement Agreement

The California Colorado River Quantification Settlement Agreement and related agreements will have the 

following effects: 

• Permit the utilization of interim surplus water. 

• Transfer as much as 30 million acre-feet of water from farms to cities in Southern California for up to the 75 year 

 term of the agreement. 

• Settle potential lawsuits between the Imperial Irrigation District and the U.S. Department of the Interior. 

• Obligate California with the sole responsibility for restoration of the Salton Sea ecosystem. 

• Provide for cooperation on the environmental review and mitigation for the Imperial Irrigation District/ San 

 Diego County Water Authority Transfer Agreement, IID/ Coachella Valley Water District Acquisition 

 Agreement, and Salton Sea habitat conservation plan/natural community conservation plan. 

• Fund a $200 million project to line with concrete a portion of the earthen All-American Canal 

 and a portion of the earthen Coachella Canal. Water conserved by reducing seepage will be transferred to San 

 Diego and the San Luis Rey Indian Tribes, who will pay proportionally for operation and maintenance costs. 

• Quantify, for the first time, the total Colorado River apportionments in California.

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These diversifi ed strategies guide the management of available 

resources in a manner that allows greater fl exibility when 

adapting to water quality and supply challenges. 

MWD built Diamond Valley Lake in the late 1990s to better 

manage water supplies between wet and dry years. Located 

near Hemet in southwestern Riverside County, the 800,000 

acre-foot reservoir nearly doubles the region’s existing surface 

storage capacity and provides increased terminal storage for 

SWP and Colorado River water. Diamond Valley Lake can also 

provide the MWD service area with a six-month emergency 

water supply after an earthquake or other disaster. It also 

provides water storage for drought protection and to meet 

peak summer demands.

The SDCWA fi nished construction of Olivenhain Reservoir in 

2003 and completed fi lling its 24,000 acre-foot capacity with 

imported water in 2005. The reservoir, just southwest of Escondido in northern San Diego County, is designed to provide 

water to the San Diego region during natural or man-made 

emergencies. It is the fi rst project completed in the SDCWA 

Emergency Storage Program.

The Inland Feeder is a conveyance facility for delivery of 

SWP water made available by the enlargement of the East 

Branch of the California Aqueduct (Figure 5-4). When it is 

completed, the Inland Feeder will deliver water by gravity to 

Diamond Valley Lake through 43.7 miles of tunnels and pipeline that start at Devil Canyon afterbay and tie into the CRA 

and Eastside Pipeline. The Inland Feeder will provide system 

reliability by linking the SWP and Colorado River systems 

and will improve water quality by allowing greater blending 

of SWP and Colorado River waters. 

A recent agreement between MWD and SBVMWD allows 

MWD to purchase additional SWP water for blending with 

Colorado River water, and to store this water in the San Bernardino groundwater basin. This new groundwater supply 

also helps to resolve long-standing groundwater issues in 

the basin. The San Gorgonio Pass Water Agency recently 

extended the pipeline east from Mentone bringing SWP water 

to Beaumont.

On Oct. 10, 2003, representatives from MWD, SDCWA, 

IID, and Coachella Valley Water District (CVWD) signed the 

Quantifi cation Settlement Agreement (QSA) and several other 

agreements that will execute several key components of the 

Colorado River Water Use Plan including establishing water 

budgets from IID and CVWD and making water transfers 

viable (see Box 5-5). The QSA includes a water transfer from 

IID to SDCWA, which began in 2003 and eventually will provide up to 200,000 acre-feet per year to San Diego County. 

The transfer will help increase water supply reliability for the 

South Coast Region.

In 2003, the SDCWA and IID consummated the largest water 

transfer agreement in the history of the United States. This 

transfer, which will eventually move 200,000 acre-feet of conserved water by farmers in the Imperial Valley annually to San 

Diego County, has helped reduce SDCWA’s dependence on 

MWD and diversifi ed its sources of imported water. The initial 

term of the agreement is for 45 years; a 30-year extension is 

possible with the mutual consent of both parties. In addition, 

SDCWA will gain an additional 77,000 acre-feet of water per 

year through projects it will undertake to line the All-American 

and Coachella canals to stop water loses that occur because 

of seepage. This program has a 110-year term.

State agencies, including DWR, SWRCB, and the California 

Bay-Delta Authority (CBDA), and the U.S. Bureau of Reclamation (USBR) are making major statewide investments in urban 

and agricultural water conservation programs, which regional 

and local agencies leverage with their own investments to 

reduce demands. As discussed in previous sections, additional 

demand reduction is achieved through passive conservation 

measures as a result of changes in manufacturing codes. 

Figure 5-4 MWD inland feeder

The Inland Feeder will provide system reliability by linking the State Water 

Project and Colorado River systems and will improve water quality by 

allowing greater blending of SWP and Colorado River waters.

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An example of this regional leveraging is MWD’s water conservation program with its member agencies. Since 1992 Metropolitan has invested more than $191 million in conservation 

programs and related activities. In 2003 MWD implemented a 

new rate structure that includes a funding source dedicated to 

water conservation, recycling, groundwater recovery, and other 

local projects. The backbone of MWD’s conservation program is 

the Conservation Credits Program, initiated in 1988, that contributes $154 per acre-foot of water conserved to assist member 

agencies in pursuing conservation opportunities. In tandem with 

these urban conservation efforts, MWD and IID entered into the 

1988 IID/MWD Water Conservation Agreement and Approval 

Agreement. This agricultural water savings program began in 

1990, and to date MWD has invested more than $200 million 

to construct, operate, and maintain projects with IID intended 

to conserve more than 100,000 acre-feet of water every year 

which can be transferred to MWD. In 2005 water savings from 

this program were calculated at 101,900 acre-feet. 

Palo Verde Irrigation District and MWD have a 35-year agreement for a land management, crop rotation, and water supply 

program, under which Palo Verde farmers will stop irrigating 

between 7 to 29 percent of their land, on a rotating basis. 

This land fallowing program is estimated to produce between 

24,500 acre-feet per year up to 110,000 acre-feet per year for 

use in Southern California. MWD will provide an estimated $6 

million to local community improvement programs to counter 

potential negative economic impacts to communities in the Palo 

Verde region.

More than $440 million, primarily from State Propositions 13 

and 50 and federal Title XVI grants, have been invested in water 

recycling programs in the region, resulting in over 500,000 

acre-feet of water available per year, including Orange County 

Water District’s (OCWD) current reuse of Santa Ana River water. 

The growth in recycled water is expected to be about 400,000 

acre-feet over the next decade. 

OCWD and Orange County Sanitation District’s new Groundwater Replenishment System is designed to increase current 

water reuse by taking treated sewer water that is currently being 

released into the ocean and purifying it through microfiltration, 

reverse osmosis, and ultraviolet light with hydrogen peroxide 

advanced oxidation treatment. The purified water will then 

be injected into a seawater barrier and pumped to percolation ponds to seep into deep aquifers and blend with Orange 

County’s other sources of groundwater. This Groundwater 

Replenishment System is projected to begin delivery of purified 

water in 2007, with potential for future expansion as needed.

The development of groundwater storage and conjunctive use 

programs has improved the region’s water supply reliability 

and overall water quality. A 2000 study by the Association 

of Groundwater Agencies indicates that existing conjunctive 

use programs in the region provide an estimated 2.5 million 

acre-feet of water per year, which is a fraction of the region’s 

conjunctive use potential. It is estimated that more than 21.5 

million acre-feet of additional water could be stored and used 

in Southern California groundwater basins with the resolution 

of institutional, water quality, and other issues. State agencies 

have supported the development of 34 groundwater management and storage projects throughout the region.

As a result of MWD’s replenishment services pricing program, 

local agencies are implementing conjunctive use programs. 

They are storing imported water in groundwater basins and 

increasing their groundwater use during the summer and 

during drought years. It is estimated that an average of 

100,000 acre-feet per year of groundwater supply is now 

produced as a result of MWD’s discount pricing of water deliveries. MWD has identified the potential for 200,000 acre-feet 

of additional groundwater production during drought years. 

To accomplish this additional drought year production, about 

600,000 acre-feet of dedicated storage capacity within the 

local basins may be required. 

An example of this type of conjunctive use program is the Las 

Posas Basin Aquifer Storage and Recovery Project. The Calleguas Municipal Water District, in cooperation with MWD, has 

initiated a conjunctive use program in the Las Posas Groundwater Basin of Ventura County. The project is designed to store 

a maximum of 210,000 acre-feet of SWP water supplies that 

can be used during water supply shortages. The project will 

be phased into operation with full operation anticipated by 

2010. To date, 18 wells have been constructed and about 

50,000 acre-feet of water is in groundwater storage.

Recent groundwater storage agreements allow additional storage in wet years. Groundwater agreements to be implemented 

in the region have the potential to put more than 53-billion 

gallons of water into storage in Orange County, the west San 

Gabriel Valley, and the Inland Empire area. Groundwater 

storage can also be accumulated outside of the South Coast 

Hydrologic Region. MWD has recently developed water storage agreements with the Kern-Delta Water District, the Mojave 

Water Agency, and the North Kern Water Storage District, 

all located outside of the region. These groundwater storage 

programs are in addition to existing exchange agreements 

with the Semitropic Water Banking and Exchange Program 

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California Water Plan Update 2005

in Kern County, the Arvin-Edison Water Storage Program 

in Kern County, and the Kern-Delta Storage Program (see 

Figure 5-5). Castaic Lake Water Agency has also entered 

into a short-term groundwater banking arrangement with 

Kern County. 

Groundwater quality issues are being identified and 

addressed at many locations throughout the region. In the 

San Gabriel Valley, the Main San Gabriel Basin Watermaster, San Gabriel Basin Water Quality Authority, Upper San 

Gabriel Valley Municipal Water District, and a number of 

water suppliers have actively pursued technical remedies for 

the groundwater quality problems. Several treatment facilities 

for removal of volatile organic compounds (VOCs) were fi rst 

constructed in the 1990s. As of June 2002, 18 treatment facilities are operational. Groundwater supplies with high nitrate 

levels are either blended with other supplies or not used at all. 

Similar cleanup efforts are being pursued in the San Fernando 

Basin by the Los Angeles Department of Water and Power 

(LADWP) and the cities of Burbank and Glendale. Several 

groundwater desalting plants are currently operated by the 

Santa Ana Water Project Authority (SAWPA), Chino Basin 

Desalting Authority, city of Corona, Eastern Municipal Water 

District, Irvine Ranch Water District, the city of Oceanside, 

West Basin MWD, and the Sweetwater Authority. Brackish 

groundwater desalting currently delivers about 100,000 acrefeet of water per year, and will increase to about 250,000 

acre-feet during the next decade. State Proposition 13 water 

bond funding is being utilized to expand desalting capacity 

in the region. 

MWD recently developed water storage agreements with the Kern-Delta Water District, the Mojave Water Agency, and the North 

Kern Water Storage District, all located outside of the region. These groundwater storage programs are in addition to existing 

exchange agreements with the Semitropic Water Banking and Exchange Program in Kern County, the Arvin-Edison Water Storage 

Program in Kern County, and the Kern-Delta Storage Program

Figure 5-5 MWD storage agreements with San Joaquin Valley agencies

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165 Volume 3 Regional Reports

The SAWPA is a joint powers authority in the eastern portion of 

the region. It represents five agencies in the counties of Orange, 

Riverside, and San Bernardino and covers a watershed area of 

2,650 square miles. It provides effective and focused watershed 

planning on a regional basis. 

SAWPA operates a brine disposal line and the Arlington 

Desalter, which facilitates disposal of waste brine from regional 

desalting plants. SAWPA has been particularly successful in 

recent years in assisting its member agencies in implementing 

several new water resources projects that enhance groundwater 

recovery, groundwater storage, water quality improvement and 

water recycling through the use of Proposition 13 Water Bond 

funding. About 20 potential groundwater recovery projects 

have been evaluated with a potential net water yield of 95,000 

acre-feet per year. 

The Port Hueneme Water Agency was formed to develop and 

operate a brackish water desalting demonstration facility for its 

member agencies in western Ventura County. Its goals are to 

improve the quality and reliability of local groundwater supplies 

and decrease seawater intrusion in the Oxnard Plain. The facility 

will provide a full-scale demonstration of side-by-side operation 

of three brackish water desalting technologies: reverse osmosis, 

nanofiltration, and electrodialysis reversal. 

Increasingly, the region’s water wholesalers, such as Castaic 

Lake Water Agency, SBVMWD, Mojave Water Agency (MWA), 

MWD, and SDCWA are acquiring part of their future supplies 

from water marketing or exchange arrangements, using the 

CRA and California Aqueduct to convey the exchanged or 

purchased water.

An agreement in late 2003 between MWA and MWD calls for 

the exchange of 75,000 acre-feet of SWP flow from the California Aqueduct. Under this accord, MWA received about 23,000 

acre-feet of MWD’s State-authorized flow through the California 

Aqueduct at the end of year 2003. Additional water exchanges 

through this agreement will depend on the amount of rain or 

snowfall available to the SWP. Water will be stored in the high 

desert’s underground aquifers to help replenish the water table, 

prevent well-deepening by residents, and meet future needs.

The South Coast region has placed an increased emphasis on 

improving watershed management and protection. Local, State, 

and federal agencies and nonprofit organizations have invested 

in several management efforts, including watershed education, 

monitoring, and wetlands management and protection. More 

than 40 entities are generating new partnerships and coalitions 

among various stakeholders in attempts to integrate elements of 

flood hazard mitigation, groundwater and storm water conservation, and management of the quality of storm water runoff, 

to better manage resources. Below are a few examples of the 

region’s watershed programs:

 • SAWPA, the largest watershed organization, was estab- 

 lished to protect and enhance the quality and supply of 

 the watershed and protect the environment by implemen- 

 tation of its watershed plan.

 • Under the guidance of the Los Angeles County Department 

 of Public Works, watershed management plans are being 

 developed for five coastal watersheds within Los Angeles 

 County. Eleven watershed and subwatershed plans have 

 been completed with eight pending or proposed plans 

 under way, making Los Angeles County the most productive 

 county in the state in terms of watershed planning.

 • The Hemet/San Jacinto Multipurpose Constructed 

 Wetlands is a collaborative project between the USBR and 

 Eastern Municipal Water District. The wetland is nearly 

 60 acres with five interconnected marshes. It provides 

 nitrogen removal of secondarily treated recycled water 

 and habitat for migratory waterfowl, shore birds, and 

 raptors along the Pacific Flyway. 

 • The San Diego Creek Watershed is operated by the Irvine 

 Ranch Water District. The watershed program helps sustain 

 a restored marsh and treats contaminated urban runoff 

 water from San Diego Creek before it enters into Newport 

 Bay in Orange County. 

 • OCWD operates the Prado Basin Wetland in Riverside 

 County. In cooperation with the U.S. Army Corps of 

 Engineers and the U.S. Fish and Wildlife Service, OCWD 

 operates 465 acres of constructed freshwater wetlands to 

 reduce the nitrogen concentration of river water. 

Looking to the Future 

The region’s water agencies generally have solid plans for adapting to changing conditions and meeting future water needs. For 

example, the 2004 Report on MWD’s water supplies states, 

“Metropolitan has a comprehensive supply plan to provide sufficient supplemental water supplies and to provide a prudent 

supply reserve over the next 20 years and beyond.” SAWPA 

has begun a 10-year integrated program to help, among other 

things, drought-proof the watershed, so it can roll off imported 

water for up to three years during drought years. The Chino 

Basin is one area that has developed an integrated conjunctive 

management program with the potential to develop 500,000 

acre-feet of new storage over the next 20 years, including new 

yield from storm water management, SWP and recycled water 

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California Water Plan Update 2005

recharge, and the implementation of aggressive water use 

efficiency programs. Water districts in the Santa Clarita Valley 

of Los Angeles County are engaged in integrated urban water 

management planning, collaborative data collection, and a new 

groundwater plan. These and other ongoing planning programs 

are important to manage changing conditions facing the region. 

Water conservation programs, water recycling, and groundwater recovery, as well as water marketing and other water supply 

augmentation responses are being examined and implemented. 

The signing of the Quantification Settlement Agreement and 

related agreements in October 2003 facilitated long-term water 

transfers from the IID and CVWP in the Colorado River Hydrologic Region to urban water users in the South Coast Hydrologic 

Region. They will help California reduce its use of Colorado River 

water to its basic allotment of 4.4 million acre-feet during years 

of normal supply. They will also make possible the transfer of 

additional water to be obtained through lining the All American 

and the Coachella canals. The water transfer between IID and 

SDCWA will help to stabilize MWD’s and CVWD’s water supplies, satisfy outstanding miscellaneous and Indian water rights, 

and provide funding that IID and farmers in the Imperial Valley 

will use to implement additional water conservation measures 

once the required fallowing is complete. 

MWD will continue its replenishment services water pricing 

program to encourage local agencies to store imported water 

in groundwater basins for use during the summer and during 

drought years. In addition, local agencies in the region are now 

planning to use water transfers for part of their base supplies, 

a change from past years when marketing arrangements were 

viewed as primarily for drought year supplies. 

In 2004 MWD updated its Integrated Water Resources Plan with 

the revised goal of achieving 1.1 million acre-feet of region-wide 

conservation by year 2025. The plan proposes to achieve this 

water conservation target utilizing several programs, including 

500,000 acre-feet from compliance with new plumbing codes 

and other laws, 250,000 acre-feet from pre-1990 conservation, 

and 300,000 from active program-based conservation.

Ocean water desalination is sometimes described as the ultimate 

solution to Southern California’s water supply shortfall. While it 

has become a more feasible source of supply due to technical 

advances, the development of desalination facilities still faces 

many challenges that include high energy requirements, environmental impacts of brine disposal, and plant-siting considerations. State agencies have provided funding for the Desalination Research and Innovation Partnership, which furthered the 

development of advance reverse osmosis membranes. 

MWD and five of its member agencies have planned for the 

potential development of 126,000 acre-feet of desalinated 

ocean water. Those member agencies include LADWP, Long 

Beach Water Department, Municipal Water District of Orange 

County, WBMWD, and SDCWA. The SDCWA expects desalted 

ocean water to meet between 6 and 15 percent of the region’s 

needs by 2020 and is conducting an environmental review for 

building an ocean water desalination facility on the Encina 

Power Plant property in Carlsbad. SDCWA also is carrying out 

feasibility studies of desalination facilities at Camp Pendleton 

and in the southern county. All three sites are on the coast. 

Another future water supply option is management of the San 

Bernardino Basin as a groundwater storage facility. The basin 

has a capacity of about 5.5 million acre-feet. Pursuant to the 

January 1969 settlement for Western Municipal Water District 

et al. vs. East San Bernardino Valley Municipal Water District 

et al. Superior Court Riverside County Case number 78426, 

the Western-San Bernardino Watermaster determined that 

the safe yield of the San Bernardino Basin is about 232,000 

acre-feet per year. SBVMWD has been working with the U.S. 

Geological Survey for many years to develop a groundwater 

computer model that will enable the agency to determine ways 

to enhance the safe yield of this basin.

The Groundwater Replenishment System, a high-technology 

water purification system, is a project under development by the 

OCWD and the Orange County Sanitation District. It will replace 

Water Factory 21, which was shut down in January 2004 in 

anticipation of construction of this new, larger system. The project 

will take highly treated wastewater and treat it beyond drinking 

water standards for groundwater recharge and injection into 

the seawater barriers along the coast. It will provide a second 

and reliable source of water to recharge the Orange County 

Basin; protect the basin from further water quality degradation 

brought on by seawater intrusion; and augment the existing 

recycled water supply for irrigation and industrial uses. In its 

first phase, the Groundwater Replenishment System will provide 

up to 72,000 acre-feet per year and allow for future expansion. 

It is expected to go online in 2007.

Flood control reservoirs are now being evaluated for their potential to provide some water supply benefits through the modification of their operations to enhance groundwater recharge and 

provide limited year-round storage. The SBVMWD, for example, 

has applied to the SWRCB for authorization to store storm water 

from the Santa Ana River in a reservoir that could be created 

behind Seven Oaks Dam. Los Angeles County Department of 

Public Works (LACDPW) is completing a study, in cooperation 

with the Army Corps of Engineers, to reauthorize four Corps 

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185 Volume 3 Regional Reports

flood control facilities in Los Angeles County for the purpose of 

capturing and safely storing storm water and then slowly releasing the water to downstream groundwater recharge facilities 

after storm events. 

The Water Augmentation Study is a long-term research project, 

led by the Los Angeles and San Gabriel Rivers Watershed Council and supported financially by its partners, the USBR, MWD, 

LACDPW, Los Angeles RWQCB, Water Replenishment District 

of Southern California, LADWP, City of Los Angeles Watershed 

Protection Division, DWR, and the city of Santa Monica. The 

purpose of the study is to explore the potential for increasing 

local water supplies and reducing urban runoff pollution by 

increasing the upstream infiltration of storm water runoff. The 

project began in January 2000 to assess the impact of runofftransported pollutants on rivers, coastal water, and beaches; the 

viability of adding these storm water resources to local water 

supplies, and the challenge of capturing storm water for infiltration, in terms of groundwater quality and quantity.

In 2000, DWR, in cooperation with the USBR and 10 Southern California water and wastewater agencies, undertook 

the Southern California Water Recycling Projects Initiative to 

continue the work previously started by the Southern California Comprehensive Water Reclamation and Reuse Study 

(SCCWRRS). The initiative is a multiyear planning study that 

evaluates the feasibility of a regional water-recycling plan and 

assists local water and wastewater agencies in final planning 

and environmental documentation leading to implementation 

of projects identified in the SCCWRRS. The initiative is funded 

on a 50-50 percent cost-sharing among the 12 agencies. The 

initiative identified short-term projects that could add about 

378,000 acre-feet of recycled water for regional use. The 15 

short-term projects were identified for the areas of Calleguas, 

East San Gabriel, West Basin, Central Basin, North Orange 

County, Central Orange County, Upper Oso, San Juan, Encina, 

San Pasqual Valley, North City, South Bay, Chino Basin, San 

Bernardino, and Eastern Basin. 

As part of a regional strategy to improve water supply reliability, 

several agreements with water districts in the Central Valley are 

providing groundwater storage for the South Coast region:

 • Semitropic Water Banking and Exchange Program. This 

 program allows storage of up to 350,000 acre-feet in the 

 groundwater basin underlying the Semitropic Water 

 Storage District in Kern County.

 • Arvin-Edison Water Storage Program. MWD and the 

 Arvin-Edison Water Storage District have developed a 

 program that allows Metropolitan to store water in the 

 groundwater basin in the Water Storage District’s service 

 area in Kern County. Over the next 25 to 30 years, this 

 groundwater storage program will provide average dry- 

 year withdrawals of about 70,000 acre-feet annually.

 • Kern-Delta Storage Program. This 25-year program will 

 allow storage of up to 250,000 acre-feet of available 

 State Water Project supplies. 

Other potential management strategies includes interstate 

groundwater banking in Arizona, drought year land fallowing programs, lining parts of the All-American and Coachella 

canals, and agricultural water conservation beyond EWMP 

implementation. In addition, South Coast region water agencies 

are storing discount-priced imported water during winter months 

into groundwater basins and increasing their groundwater use 

during the summer and during droughts. 

The Calleguas Municipal Water District operates a conjunctive 

use program in the Las Posas Groundwater Basin of Ventura 

County. Identified as the Las Posas Basin Aquifer Storage and 

Recovery Project, it is designed to store a maximum of 300,000 

acre-feet of water supplies that can be used during short-term 

and long-term water supply shortages. The project calls for the 

construction of 30 dual-purpose groundwater wells that will be 

used for both injection and water production. Pipelines will be 

constructed to connect the wells with CMWD facilities as far 

away as the Cities of Simi Valley and Thousand Oaks. The source 

of water supplies would be the State Water Project. The project 

will be phased into operation with full operation anticipated 

by 2010. To date, 18 wells have been built and about 50,000 

acre-feet of water is in storage.

To improve the reliability of its potable water supplies during 

droughts, the Western Municipal Water District is moving 

forward with plans to operate a conjunctive use program in 

groundwater basins in western San Bernardino and Riverside 

counties. The project, the Riverside-Corona Feeder, calls for the 

recharge of water supplies during above-average precipitation 

years into the groundwater basins in San Bernardino Valley 

and pumping those supplies during drought years. Sources 

of water for the recharging operations would be local surface 

runoff, including releases from the Seven Oaks Reservoir near 

the community of Mentone in San Bernardino County and the 

SWP. Recipients of the stored groundwater supplies are the 

cities of Corona and Riverside and the Elsinore Valley Water 

District. When completed, 20 wells and 28 miles of pipeline will 

have been constructed. About 40,000 acre-feet of groundwater 

supplies could be achieved through this project. 

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California Water Plan Update 2005

Most of the projects described above are designed to improve 

water quality as the way to obtain increased water supplies. These 

include watershed activities, such as the Water Augmentation 

Study, groundwater desalination, use of highly treated recycled 

water by the OCWD, reduction of sewage spills and storm water 

runoff through water conservation, and surface and groundwater storage projects that implement blending and treatment strategies to reduce contaminants in treated drinking water supplies. 

In addition, MWD is committed to retrofitting all five of its 

water treatment plants to use ozone; adding fluoride to treated 

drinking water supplies; implementing a recreation policy for 

Diamond Valley Lake that protects drinking water quality; and 

supporting salinity reduction projects throughout the region. 

Outside the region MWD also supports efforts to preserve 

and enhance the Sacramento River watershed and the Delta, 

which are important to the operation of the SWP system.

Water Portfolios for Water Years 

1998, 2000, and 2001

Hydrologic conditions for water years 1998, 2000, 2001 

impacted the water supply and water use characteristics for 

the South Coast Hydrologic Region. These three years were 

selected because 1998 represents actual supplies and uses in 

a very wet year, 2000 presents water uses in a near-average 

water year (on a statewide basis), and 2001 presents the actual 

data for supplies and uses in a drier water year. In water year 

1998, rainfall totals ranged from 170 percent of average in San 

Diego County to more than 250 percent of average in Ventura 

County with more than 50 percent of the annual precipitation in 

January and February. In comparison, during water year 2000 

rainfall totals ranged from 60 percent of average in San Diego 

County to more than 100 percent of average in Ventura County. 

Precipitation amounts for the region for water year 2000 were 

average to moderately below average. Rainfall deficits increased 

from north to south. Water year 2001 was a dry year statewide, 

although closer to normal levels of precipitation (92 percent of 

average) occurred for the South Coast region.

Table 5-1 provides more detailed information about the total 

water supplies available to this region for these three specific 

years from precipitation, imports, and groundwater, and also 

summarizes all of the water uses in the region, including the 

large amount of evapotranspiration from vegetation and forests. 

The water portfolio table (Table 5-3) and companion water 

portfolio flow diagrams (Figures 5-6 and 5-7) provided more 

detailed information about how all available water supplies are 

distributed and used throughout this region.

Table 5-3 presents specific information about the developed 

or dedicated portion of the total available water for years 

1998, 2000, and 2001, which summarizes all water that is 

used for urban, agricultural, and environmental purposes. The 

South Coast region’s relatively high level of urban development is reflected in the data for urban water use patterns. In 

1998, 78 percent of all applied water use in the region was 

urban. In 2000 and 2001, urban use accounted for about 81 

percent of total water use in regional. By contrast, agriculture 

only accounted for 15 percent of all applied water in 1998; 

17 percent in 2000; and 15 percent in 2001. Table 5-3 also 

provides detailed information about the sources of the developed water supplies, which are obtained from a mix of both 

surface water, groundwater supplies, and recycled water. 

Selected References

2002 California 305(b) Report on Water Quality, State 

Water Resources Control Board 

2002 Statewide Recycled Water Survey, State Water 

Resources Control Board, 2003. Available: www.swrcb. 

ca.gov/recycling/recyfund/munirec/index.html 

Annual Progress Report to the California State Legislature, 

MWD, February 2004 

Annual Report of the Santa Clarita Valley Water Purveyors 

California’s Groundwater, Bulletin 118-03 (Draft), Update 

2003, California Department of Water Resources 

Correspondence with watershed and water wholesale and 

retail delivery agencies. 

Groundwater Replenishment System Web site: 

www.gwrsystem.com/ 

Matilija Dam Ecosystem Restoration Feasibility Study. Public 

Draft Report. July 2004. Available: www.matilijadam. 

org/public-report.htm 

Nonpoint Source Program Strategy and Implementation Plan, 

1998-2013, State Water Resources Control Board, 

California Coastal Commission, January 2000 

San Diego County Water Authority – Water Management 

– Recycling Web site: www.sdcwa.org/manage/sourcesrecycling.phtml 

Strategic Plan, State Water Resources Control Board, Regional 

Water Quality Control Boards, November 15, 2001 

Water Quality Control Plan, Regional Water Quality Control Board 

Watershed Management Initiative Chapter, Regional Water 

Quality Control Board

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Water Portfolios

South Coast Hydrologic Region

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225 Volume 3 Regional Reports

Table 5-3 South Coast Region water portfolio (TAF) 

 ID South Coast South Coast South Coast

Number: Flow Diagram Component (see legend) 1998 2000 2001

 1 Colorado River Deliveries 1,081.3 1,296.0 1,250.5

 2 Total Desalination - - -

 3 Water from Refineries - - -

 4a Inflow From Oregon - - -

 b Inflow From Mexico - - -

 5 Precipitation 20,873.0 7,522.1 9,327.0

 6a Runoff - Natural N/A N/A N/A

 b Runoff - Incidental N/A N/A N/A

 7 Total Groundwater Natural Recharge N/A N/A N/A

 8 Groundwater Subsurface Inflow N/A

 9 Local Deliveries 292.1 211.4 217.1

 10 Local Imports 442.0 294.0 272.0

 11a Central Valley Project :: Base Deliveries - - -

 b Central Valley Project :: Project Deliveries - - -

 12 Other Federal Deliveries 4.2 0.6 -

 13 State Water Project Deliveries 687.7 1,300.1 958.7

 14a Water Transfers - Regional - - -

 b Water Transfers - Imported - - -

 15a Releases for Delta Outflow - CVP 

 b Releases for Delta Outflow - SWP 

 c Instream Flow Applied Water 3.5 3.5 3.5

 16 Environmental Water Account Releases - - -

 17a Conveyance Return Flows to Developed Supply - Urban - - -

 b Conveyance Return Flows to Developed Supply - Ag - - -

 c Conveyance Return Flows to Developed Supply - Managed Wetlands - - -

 18a Conveyance Seepage - Urban - - -

 b Conveyance Seepage - Ag - - -

 c Conveyance Seepage - Managed Wetlands - - -

 19a Recycled Water - Agriculture - - -

 b Recycled Water - Urban 202.4 182.7 188.8

 c Recycled Water - Groundwater 2.1 37.1 36.2

 20a Return Flow to Developed Supply - Ag - - -

 b Return Flow to Developed Supply - Wetlands - - -

 c Return Flow to Developed Supply - Urban - - -

 21a Deep Percolation of Applied Water - Ag 87.2 114.4 95.2

 b Deep Percolation of Applied Water - Wetlands - - -

 c Deep Percolation of Applied Water - Urban 321.6 386.5 367.0

 22a Reuse of Return Flows within Region - Ag - - -

 b Reuse of Return Flows within Region - Wetlands, Instream, W&S 287.7 37.8 111.7

 24a Return Flow for Delta Outflow - Ag - - -

 b Return Flow for Delta Outflow - Wetlands, Instream, W&S - - -

 c Return Flow for Delta Outflow - Urban Wastewater - - -

 25 Direct Diversions 

 26 Surface Water in Storage - Beg of Yr 1,380.6 1,515.5 1,643.3

 27 Groundwater Extractions - Banked - - -

 28 Groundwater Extractions - Adjudicated 786.0 865.0 841.3

 29 Groundwater Extractions - Unadjudicated 846.3 1,008.4 1,020.9

 23 Groundwater Subsurface Outflow N/A N/A N/A

 30 Surface Water Storage - End of Yr 1,752.5 1,643.3 1,975.6

 31 Groundwater Recharge-Contract Banking - - -

 32 Groundwater Recharge-Adjudicated Basins - - -

 33 Groundwater Recharge-Unadjudicated Basins - - -

 34a Evaporation and Evapotranspiration from Native Vegetation 

 b Evaporation and Evapotranspiration from Unirrigated Ag 

 35a Evaporation from Lakes 18.5 18.5 17.9

 b Evaporation from Reservoirs 149.1 164.2 160.8

 36 Ag Effective Precipitation on Irrigated Lands 256.8 150.2 166.1

 37 Agricultural Water Use 691.9 908.4 758.4

 38 Managed Wetlands Water Use 31.2 38.1 37.2

 39a Urban Residential Use - Single Family - Interior 990.7 1,252.8 1,144.3

 b Urban Residential Use - Single Family - Exterior 670.2 752.1 709.0

 c Urban Residential Use - Multi-family - Interior 603.2 543.1 510.0

 d Urban Residential Use - Multi-family - Exterior 105.9 139.7 151.0

 40 Urban Commercial Use 699.5 914.1 885.5

 41 Urban Industrial Use 186.0 209.8 209.8

 42 Urban Large Landscape 165.7 242.8 187.5

 43 Urban Energy Production 39.8 39.8 39.8

 44 Instream Flow - - -

 45 Required Delta Outflow - - -

 46 Wild and Scenic Rivers - - -

 47a Evapotranspiration of Applied Water - Ag 494.8 645.8 542.9

 b Evapotranspiration of Applied Water - Managed Wetlands 31.2 38.1 37.2

 c Evapotranspiration of Applied Water - Urban 941.8 1134.6 1047.5

 48 Evaporation and Evapotranspiration from Urban Wastewater - - -

 49 Return Flows Evaporation and Evapotranspiration - Ag 11.2 15 12.3

 50 Urban Waste Water Produced 1824.8 2156.8 2015.9

 51a Conveyance Evaporation and Evapotranspiration - Urban 346.5 362.5 358.5

 b Conveyance Evaporation and Evapotranspiration - Ag - - -

 c Conveyance Evaporation and Evapotranspiration - Managed Wetlands - - -

 d Conveyance Outflow to Mexico 

 52a Return Flows to Salt Sink - Ag 100.1 135.1 110.1

 b Return Flows to Salt Sink - Urban 2009.7 2363.3 2214.8

 c Return Flows to Salt Sink - Wetlands - - -

 53 Remaining Natural Runoff - Flows to Salt Sink - - -

 54a Outflow to Nevada - - -

 b Outflow to Oregon - - -

 c Outflow to Mexico - - -

 55 Regional Imports 2,367.0 2,991.0 2,505.0

 56 Regional Exports 0.0 0.0 0.0

 59 Groundwater Net Change in Storage -1,223.5 -1,372.5 -1,400.0

 60 Surface Water Net Change in Storage 371.9 127.8 332.3

 61 Surface Water Total Available Storage 2,112.7 3,058.8 3,058.8

 

 Inflows Outflows Green number signifies included in summary boxes 

 

EE-RM-PET-100 C0MMENT 01A
Figure 5-6 South Coast region - illustrated water flow diagram

INFLOWS

SUMMARY

OUTFLOWS

8

15a,b

21

27

31

45

48

51

5

6

46

14 16

33

28

29

32

39- 43

59

50

18

9

51

34

47b

38

35

51

26

30

60

61

11

12

13

15c

54

56

7

1

4

55

10 44

36

47a

49

51

37

17

20

47c

22

25 24

31

23

2

3

52

53

19

In this illustration of Table 5-3, key components of the flow diagram are shown as characteristic elements of the hydrologic cycle. Circled numbers correspond to the identification number of flow diagram components in the table; its color indicates whether the component is water input, output, or summary.

52

Volume 3 Regional Reports Chapter 5 South Coast Hydrologic Region 5 23

California Water Plan Update 2005

EE-RM-PET-100 C0MMENT 01A
SUMMARY

OUTFLOWS

INFLOWS

Figure 5-7 South Coast region - schematic flow diagram

In schematic of Table 5-3, key components of the flow diagram are shown as boxes and connectors in a flow chart. Circled numbers correspond to the identification number of flow diagram components in the table; box color indicates whether component is water input, output, or summary. 

Blank boxes are flow diagram components not relevant to the region. 

Service Area

COLORADO R 

DELIVERIES:

RUNOFF:

NATURAL: 

INCIDENTAL: 

PRECIPITATION: TOTAL STREAM 

FLOW: 

AG EFFECTIVE 

PRECIPITATION ON 

IRRIGATED LANDS: 

LOCAL IMPORTED 

DELIVERIES:

LOCAL

DELIVERIES:

SURFACE WATER IN 

STORAGE:

Beg of Yr:

 End of Yr: 

SWP DELIVERIES: WATER DEPOSITS: 

SURFACE WATER: 

GROUNDWATER: 

RECYL & DESAL:

TRANSFERS:

TOTAL GROUNDWATER NATURAL RECHARGE: 

GROUNDWATER CHANGE IN STORAGE: 

BANKED:

ADJUDICATED: 

UNADJUDICATED: 

 Sum of known quantiti

GW EXTRACTIONS:

CONTRACT BANKS:

ADJUDICATED BASINS: 

UNADJUDICATED BASINS: 

EVAPOTRANSPIRATION 

OF APPLIED WATER: 

AG:

WETLANDS:

URBAN:

WATER USE (APPLIED): 

AGRICULTURAL: 

WETLANDS:

URBAN:

TOTAL 

RECYCLED WATER: 

AG:

URBAN:

GW: 

URBAN

WASTEWATER 

PRODUCED:

INCIDENTAL E & ET 

AG RETURN FLOWS: 

AG & WETLANDS 

RETURN FLOWS:

RETURN FLOWS TO SALT 

SINKS:

AG:

WETLANDS:

URBAN:

REMAINING NATURAL 

RUNOFF

FLOW TO SALT SINKS:

DEEP PERC OF APPLIED 

WATER: 

AG:

WETLANDS:

URBAN:

RETURN FLOW TO 

DEVELOPED

SUPPLY: 

AG:

WETLANDS:

URBAN:

EVAP FROM: 

LAKES: 17.9

RESERVOIRS:

E & ET FROM:

NATIVE VEGETATION: 

UNIRRIGATED AG: 

Return Flow 

within

RELEASES FOR 

INSTREAM USE: 

DIRECT

DIVERSIONS:

CONVEYANCE E&ET, 

RETURN FLOWS, & 

SEEPAGE:

URBAN:

AG:

WETLANDS:

CONVEYANCE E & ET: 

URBAN:

AG:

WETLANDS:

CONVEYANCE RETURN 

FLOWS:

URBAN:

AG:

WETLANDS:

CONVEYANCE SEEPAGE: 

URBAN:

AG:

WETLANDS:

MEXICO:

RETURN FLOW FOR 

DELTA OUTFLOW: 

AG:

WETLANDS:

URBAN :

EVAPORATION AND EVAPOTRANSPIRATION OF APPLIED WATER, 

PRECIPITATION AND CONVEYANCE: 

GW RECHARGE:

CONTRACT BANKING:

ADJUDICATED BASINS: 

UNADJUDICATED BASINS: 

SUBSURFACE GW 

INFLOW: 

SUBSURFACE 

GROUNDWATER 

OUTFLOW: 

OTHER REGIONAL 

TRANSFER OUT:

REGIONAL

TRANSFER IN: 

Return of

Required Instream 

Flows

Return of

Required Wild & 

Scenic Flows

TO E & ET:

1

2

5

4

3

55

6

13

11

19

12

10

9

7

20

21

45

29

26

30

35

39 to 43

37

38

53

54

46

14

34 36

28

52

16

24

17

18

25

47

50

49

48

27

31

32

33

23

8

15C

15A

15B

56

44

16

51

22

5 24 Chapter 2 South Coast Hydrologic Region Volume 3 Regional Reports

California Water Plan Update 2005

EE-RM-PET-100 C0MMENT 01A
Chapter 6 Sacramento River Hydrologic Region 

Volume 3 

EE-RM-PET-100 C0MMENT 01A
Chapter 6 Sacramento River Hydrologic Region i6

California Water Plan Update 2005

Chapter 6 Sacramento River Hydrologic Region

Contents

Chapter 6 Sacramento River Hydrologic Region ........................................................................................................6-1

Setting ................................ 6-1

Population .......................... 6-2

Water Supply and Usage ..... 6-3

 Current Situation ............ 6-5

State of the Region .............. 6-5

 Challenges .................... 6-9

 Accomplishments ......... 6-10

Looking to the Future ......... 6-13

 Changes in Water Demands for 2030 Scenarios ............................................................................................6-15

 Regional Planning and Coordination .............................................................................................................6-15

Water Portfolios for Water Years 1998, 2000, and 2001 .....................................................................................6-15

Selected References ........... 6-15

Figures

Figure 6-1 Sacramento River Hydrologic Region (map) ..............................................................................................6-ii

Figure 6-2 Butte Creek progress ...............................................................................................................................6-3

Figure 6-3 Sacramento River Hydrologic Region population .......................................................................................6-4

Figure 6-4 Sacramento River region water balance for water years 1998, 2000, 2001 (2 bar charts) ...........................6-8

Figure 6-5 Sacramento River region - illustrated water flow diagram .........................................................................6-19

Figure 6-6 Sacramento River region - schematic flow diagram ..................................................................................6-20

Tables

Table 6-1 Sacramento River region population density by county ................................................................................6-4

Table 6-2 Sacramento River Hydrologic Region water balance summary .....................................................................6-6

Table 6-3 Sacramento River region water use and distribution of dedicated supplies ....................................................6-7

Table 6-4 Sacramento River region water portfolios .................................................................................................6-18

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California Water Plan Update 2005

Some Statistics

 Area - 27,246 square miles (17.2% of State)

 Average annual precipitation - 36.7 inches

 Year 2000 population - 2,593,110

 2030 population projection - 4,569,490

 Total reservoir storage capacity - 16,146 TAF

 2000 irrigated crop area - 2,038,900 acres

.

.

.

.

.

.

Flow in TAF

1998

10

2000

9

2001

7

North Lahontan Region

Little Truckee

Flow in TAF

1998

851

2000

1,111

2001

669

North Coast Region

Trinity River (CVP)

Flow in TAF

1998

2

2000

2

2001

2

North Coast Region

North Fork Ditch

Flow in TAF

1998

3

2000

3

2001

3

North Lahontan Region

Pit River

Flow in TAF

1998

0

2000

1

2001

2

North Lahontan Region

Echo Lake Conduit

Flow in TAF

1998

40

2000

30

2001

23

San Joaquin River Region

Sly Park

Flow in TAF

1998

69

2000

72

2001

80

San Francisco Bay Region

Putah South Canal

North Bay Aqueduct (SWP)

Vallejo Permit Water

Flow in TAF

1998

5,119

2000

6,174

2001

4,572

San Joaquin River Region

Delta Mendota Canal

Folsom South Canal

California Aqueduct

TEHAMA

GLENN

LAKE COLUSA

BUTTE

YUBA

SUTTER

NEVADA

SIERRA

SACRAMENTO

YOLO

NAPA

SOLANO

PLACER

EL DORADO

PLUMAS

SISKYOU MODOC

SHASTA

LASSEN

Figure 6-1 Sacramento River Hydrologic Region

The Sacramento River Hydrologic Region includes the entire drainage area of California’s largest river and its tributaries, extending from the Oregon 

border to Sacramento. Arrows indicate annual flows entering and leaving the region for water years 1998, 2000, and 2001. 

Flow in TAF

1998

43,487

2000

18,156

2001

6,944

Sacramento River

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Chapter 6 Sacramento River Hydrologic Region 6 1

California Water Plan Update 2005

Chapter 6 Sacramento River Hydrologic Region

The Sacramento River Hydrologic Region also encompasses all 

or a portion of six of the state’s 18 national forests. Lassen, Mendocino, Modoc, Plumas, Shasta-Trinity and Tahoe Basin national 

forests are contained or contiguous to the region and contribute 

to the dynamics of its vast landscape. These federal lands are 

each managed with specific goals for fish and wildlife such as 

the recovery of the spotted owl or the Chinook salmon, as well 

as for hydroelectric power and sustainable timber harvest. Such 

diverse goals often call for creative management strategies.

Agriculture is the region’s largest industry, contributing a wide 

variety of crops including rice, grain, tomatoes, field crops, fruits 

and nuts. Crop statistics show that irrigated agricultural acreage 

in the region peaked during the 1980s and has since declined 

with a little more than 2 million acres irrigated in 2000. Excess 

applied irrigation water generally returns to the supply system 

through drainage canals, or recharges groundwater. Basin efficiency is usually very good because downstream users recycle 

return flows for their own use. In some places, return flows are 

the only water source for downstream agricultural users. 

The southern portion of the Sacramento River Hydrologic Region 

is experiencing rapid population growth and urbanization. 

While California experienced a statewide population increase 

approaching 15 percent from 1990 to 2000, growth rates in 

the Sacramento metropolitan region have exceeded this trend. 

According to California Department of Finance projections, 

Sacramento County’s population increased by 17.5 percent 

between 1990 and 2000, and is projected to grow by 26 percent between 2000 and 2010 to more than 1.5 million people. 

Similarly, the adjoining urban areas in Placer, El Dorado and 

Yolo counties are also experiencing the same levels of extensive growth and urban expansion. This ongoing rapid rate of 

urbanization is expected to generate significant land and water 

use challenges for the entire southern portion of the Sacramento 

River region, including adequate drought-period water supplies, 

growth in flood plains, conversion of productive farmland, and 

the preservation of sensitive environmental habitats.

Setting

The Sacramento River Hydrologic Region includes the entire 

drainage area of the state’s largest river and its tributaries, 

extending from the Oregon border downstream to the 

Sacramento – San Joaquin Delta. The region covers 27,246 

square miles including all or a portion of 20 predominately 

rural Northern California counties, and extends from the 

crest of the Sierra Nevada in the east to the summit of the 

Coast Range in the west (Figure 6-1). The northernmost area, 

mainly high desert plateau, is characterized by cold, snowy 

winters with only moderate rainfall, and hot, dry summers. The 

mountainous parts in the north and east typically have cold, 

wet winters with large amounts of snow providing runoff for 

summer water supplies. The Sacramento Valley floor has mild 

winters with less precipitation and hot dry summers. Overall 

annual precipitation in the region generally increases as you 

move from south to north and west to east. The heavy snow 

and rain that falls in this region contributes to the overall water 

supply for the entire state.

The many rivers and streams that are tributary to the Sacramento River provide important riparian habitat that is critical 

for many aquatic and terrestrial species including the springrun Chinook salmon (Oncorhynchus tshawytscha), winter-run 

Chinook salmon (Oncorhynchus tshawytscha) and Central 

Valley steelhead (oncorhynchus mykiss). (For more information 

about increased concern over decline of endangered salmon, 

see Figure 6-2 and discussion under Ecosystem Restoration.) 

This region is the only known area for the winter-run Chinook. 

The valley floor region section adjoining the river, provide 

some of the most important wintering areas along the Pacific 

Flyway for many varieties of waterfowl. The region also has 

several wetland and waterfowl preserves that provide nesting 

and migration areas for threatened avian species including 

the bald eagle and Swainson’s hawk and numerous species 

of neotropical birds. All of these valuable resources are vital 

components of the ecosystem and contribute to the ecological 

health of the entire state.

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California Water Plan Update 2005

6 2 Volume 3 Regional Reports

For the central and northern portions of the Sacramento River 

region, most urban development has occurred along the main 

highway corridors. Although a few of the larger cities in the 

region, such as Sacramento, divert most of their water from the 

larger rivers, the principal source of water for most of the urban 

and rural communities throughout this region is groundwater. The 

Sacramento Valley is recognized as one of the foremost groundwater basins in the state. In the rural mountain areas of this 

region, domestic supplies come almost entirely from groundwater. 

Population

The population of the Sacramento River Hydrologic Region 

was 2,593,000 in 2000, which represents about 8 percent of 

California’s total population. Table 6-1 provides an additional 

breakdown by county for populations, land areas, and the 

resulting population density. Geographically, Siskiyou County 

has the largest acreage in the region, 6,287 square miles, but 

with a 2000 population of only 44,750 the population density 

is about seven people per square mile. On the other hand, 

Sacramento County is the most populated county in the region, 

with a density of 1,274 people per square mile. When looking 

at the map of the region in Figure 6-1, it should be noted that 

both of these counties are only partially in the region. However, 

these statistics are useful in portraying the environment of the 

region, which, except for Sacramento, is predominately rural 

in nature with low population ratios per square mile. 

Although 2000 population numbers indicate lower densities 

than other developed regions of the state, it is projected that the 

Sacramento River region’s total population will increase to more 

than 4.5 million by the year 2030. Figure 6-3 provides a graphical depiction of the Sacramento River region’s total population 

from 1960 through 2000, with current projections to 2030. This 

growth will have a significant impact on shaping the natural 

resources of the region. Population per square mile decreases 

as you move farther north into the region, which contains large 

areas of agriculture and forested lands, both private and public. 

The Sacramento River region includes the entire drainage area of the state’s largest river and its tributaries, extending from the Oregon border downstream 

to the Sacramento–San Joaquin Delta. In this photo, the Sacramento River flows near downtown Sacramento. (DWR Photo)

EE-RM-PET-100 C0MMENT 01A
Chapter 6 Sacramento River Hydrologic Region 6 3

California Water Plan Update 2005

Future land use planning and decisions, at both the state and 

local level, will need to consider the changing complexion 

of the region, as well how to best use and preserve the vast 

open spaces and abundant natural resources in the region. 

Water Supply and Usage

Because of the weather patterns that produce a high level 

of precipitation in the region, major water supplies from the 

region are provided through the development of reservoirs 

and from direct groundwater pumping, which historically 

has recharged through the winter months. Major reservoirs 

in the region provide water supply, recreation, power, environmental, and fl ood control benefi ts. The Central Valley 

Project (CVP) is the largest water project in the state, and 

includes Shasta Lake, Whiskeytown Lake, Keswick Reservoir 

and Folsom Lake in this region. A large portion of the water 

supplied by CVP is delivered for agriculture purposes, both 

in this region and as water exports to other regions. The U.S. 

This performance measure reports the escapement (the number of adult salmon escaping mortality and successfully returning each year

to spawn) of adult spring-run Chinook salmon, a threatened species under the state and federal Endangered Species acts, on Butte Creek.

The Butte Creek population is one of the few remaining self-sustaining populations of spring-run Chinook salmon in the Central Valley. The 

spring-run in Butte Creek has been affected by significant impediments to upstream passage of adults stemming from dams, inoperative fish

ladders, and reduced flows as a result of water diversions. Since 1995, restoration actions have included dam removal, installation and/or 

repair of fish ladders and fish screens, and improvements to base flow.

Spring Run Chinook Salmon on Butte Creek

Figure 6-2 Butte Creek Progress

Increased concern over the decline in endangered salmon has stimulated several projects and programs. Figure shows number of returning 

adult spring-run Chinook salmon in Butte Creek from 1970 to 2003. Restoration projects and programs are listed by year of implementation.

Bureau of Reclamation’s (USBR) Solano Project provides urban 

and agricultural water supply to parts of the Sacramento River 

Region and parts of the San Francisco Bay region. The major 

water supply facilities of the State Water Project (SWP) are along 

the Feather River basin in this region, consisting of Lake Oroville, 

Thermalito Afterbay, Lake Davis and Frenchman Reservoir. SWP 

water serves both urban and agricultural uses in this region and 

are exported south to other drier regions of the state. A large 

amount of water from both CVP and SWP reservoirs is released 

downstream to maintain environmental water quality standards 

in the Sacramento – San Joaquin Delta. Such storage releases 

are critical in the summer and fall, to prevent ocean salt water 

from penetrating east into the Delta during high tidal cycles.

There are several other, smaller reservoirs that add to the 

overall surface water supply. In total, the region has 43 reservoirs, with a combined capacity of almost 16 million acre-feet. 

Major reservoirs in the region provide not only water supply, 

but also are the source of recreation, power generation, and 

EE-RM-PET-100 C0MMENT 01A
California Water Plan Update 2005

6 4 Volume 3 Regional Reports

Data from California Department of Finance provide decadal population from 1960 to 2000 and population projection for 2030 

for the Sacramento River region.

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

4,500,000

5,000,000

1960 1970 1980 1990 2000 2010 2020 2030

Figure 6-3 Sacramento River Hydrologic Region population

County Population Square Miles Persons Per

 Square Mile

Butte 204,500 1639 125

Colusa 19,050 1151 17

El Dorado 159,700 1711 93

Glenn 26,750 1315 20

*Lake 58,800 1258 47

*Lassen 34,300 4557 8

*Modoc 9,375 3944 2

*Napa 125,400 754 166

Nevada 92,200 958 96

Placer 248,900 1404 177

Plumas 20,750 2554 8

Sacramento 1,230,600 966 1,274

Shasta 165,200 3785 44

*Sierra 3,610 953 4

*Siskiyou 44,750 6287 7

Sutter 79,400 603 132

Tehama 55,800 2951 19

*Trinity 13,000 3179 4

Yolo 169,400 1013 167

Yuba 60,700 631 96

* Represents counties only partially covered within the region

 California Dept. of Finance (July, 2001 Estimated)

Table 6-1

Sacramento River Region Population Density by County

other environmental and fl ood control benefi ts. In addition, the 

region has a network of creeks and rivers that convey water for 

use throughout the region and also provide nesting and rearing 

grounds for major fi sh and wildlife species. Figure 6-4 provides 

a graphical presentation of the categories of the water supply 

sources that are used to meet the developed water uses in this 

hydrologic region for 1998, 2000 and 2001.

Water use in the Sacramento River region is mostly for agricultural production with more than 2.0 million irrigated acres in 

2000. Agricultural products include a variety of crops such as 

rice and other grains, tomatoes, fi eld crops, fruits and nuts. A 

substantial number of acres of rangeland in this region are also 

used for livestock management. Much of the economy of the 

region relies on agricultural water supplies, which are diverted 

and distributed through extensive systems of diversion canals 

and drains. Basinwide water use effi ciency is generally high, 

because many return fl ows from fi elds are captured by drainage systems and then re-supplied to other fi elds downstream. 

In some places, these return fl ows are the primary water source 

for other downstream uses, including agriculture and wildlife 

refuges. The water quality of these return fl ows is a concern 

for some downstream users, because agricultural runoff can 

contain elevated levels of pesticides and fertilizer salts. In addition, excess applied irrigation water can return to the supply 

system by percolating as groundwater recharge.

The larger urban areas in the region have developed near 

major rivers, so surface water diversions are a key component 

of municipal water supplies. However, the Sacramento Valley is 

also recognized as having one of the foremost groundwater basins 

EE-RM-PET-100 C0MMENT 01A
Chapter 6 Sacramento River Hydrologic Region 6 5

California Water Plan Update 2005

in the state. The availability of abundant groundwater supplies 

under the valley floor has allowed urban areas to expand delivery capabilities by including the use of groundwater. In some 

areas, groundwater has become the principle source of water 

supply for urban as well as rural domestic uses.

In-stream flows, refuges and wildlife areas are the principal 

environmental use of water in the region. With the federal 

and state listing of the spring-run Chinook salmon, winter-run 

Chinook and Central Valley steelhead, much attention has been 

given to the recovery of these species and their related habitat. 

Tributaries to the Sacramento River, as well as the main stem 

itself, have been the focus of a number of ecosystem-related 

projects designed to increase the amount of environmental 

water use for habitat and species restoration.

In addition, the Sacramento Valley serves as a breeding and 

resting ground along the Pacific Flyway. Therefore, in more 

recent years, duck and other waterfowl habitat development in 

the valley section by duck clubs, non-profit groups and natural 

resource agencies have resulted in an increase in the use of 

environmental water in an attempt to increase the numbers 

of waterfowl species residing in or using the region. Certain 

agricultural practices are known to benefit many species of 

wildlife. The programs that provide the most benefits are the 

rice straw decomposition program and the use of agricultural 

return flow to refuges and duck clubs, which are designed 

to improve air and water quality in the valley. As a result of 

these programs, and other resource management activities, 

the Sacramento River region contains the largest and most 

extensive wetlands in the state. The Sacramento River region 

has a number of acres in both private and public ownership dedicated to managed wetlands. For example, in the 

northeastern mountain counties, associated with the Pit River 

system, such as the Big Valley and Alturas area, there are 

about 14,000 acres of managed wetlands. Farther south, 

in the Sacramento Valley, there are 16,987 acres in federal 

ownership; 11,987 acres of State lands; and 28,642 acres 

in private ownership managed as wetlands.

With the listing of the winter-run Chinook, spring-run Chinook 

salmon and Central Valley steelhead, much of the water 

diverted out of the Sacramento River waterways for agricultural use, environmental uses and refuge water supplies 

passes through state-of-the-art fish screens. These fish screens 

minimize take of the species when water is diverted from the 

river, and also increases system flexibility, allowing year-long 

diversion of water for agricultural purposes.

Current Situation

Table 6-2 presents a Water Supply Balance for this hydrologic 

region for 1998, a wet year; 2000, an average year; and 2001, 

a drier year. The total sources of all water supplies to the region 

are tabulated in the top portion of Table 6-2, the major uses of all 

water are shown in the middle section, and estimated interaction 

with groundwater storage is shown at the bottom of the table. 

Using 2000 as an example, a significant portion of the precipitation (57 million acre-feet) is used by native vegetation (forests), 

evaporation, unregulated runoff and percolation to groundwater, tabulated as 26.5 million acre-feet. Statutory Required 

outflows to maintain Delta water quality requirements (SWRCB 

Decision 1630) are the next largest component of water use, 

12.3 million acre-feet, followed by consumptive use of applied 

water in the Sacramento River region, 5.56 million acre-feet, 

and water exports to other regions 6.2 million acre-feet. Table 

6-3 provides more specific information about the developed or 

dedicated component of water supplies for agricultural, urban 

and environmental purposes, as assembled from actual data 

for 1998, 2000 and 2001. This table provides more specific 

information regarding the distribution of developed water, with 

large components used for environmental and agricultural purposes. Note that the environmental water use component of this 

table includes the amount required to maintain Delta outflow 

standards, which amounts to more than half of the tabulated 

environmental water usage. Figure 6-4 presents a bar chart 

that summarizes only the dedicated and developed urban, agricultural and environmental water uses in this hydrologic region.

State of the Region

Lands that are irrigated with groundwater generally enjoy a 

reliable supply as do those urban areas that depend on groundwater as all or part of their supply. However, in the foothills, 

groundwater development in fractured rock sources are highly 

variable in terms of water quantity and water quality and are 

an uncertain source for large-scale residential development. In 

the more rural portions of this region, small, widely dispersed 

populations translate into high per capita costs for municipal 

water system maintenance and improvements. Historic development pattern of small geographically dispersed population 

centers can constrain the ability to interconnect individual 

water systems or to develop centralized sources of good quality 

municipal water supplies because major capital improvement 

projects become more expensive. 

Exports from the Sacramento Valley are a concern for some 

water interest groups in the region, because they are fearful 

of losing this resource which is a key component to future 

EE-RM-PET-100 C0MMENT 01A
California Water Plan Update 2005

6 6 Volume 3 Regional Reports

Water Entering the Region

Precipitation 89,500 57,106 35,895

 Inflow from Oregon/Mexico 0 0 0

 Inflow from Colorado River 0 0 0

 Imports from Other Regions*** 901 1,150 700

Total 90,401 58,256 36,595

Water Leaving the Region

 Consumptive Use of Applied Water * 4,119 5,532 5,456

 (Ag, M&I, Wetlands) 

 Outflow to Oregon/Nevada/Mexico 0 0 0

 Exports to Other Regions*** 5,194 6,251 4,657

 Statutory Required Outflow to Salt Sink 11,039 8,879 5,663

 Additional Outflow to Salt Sink 35,112 12,328 3,940

 Evaporation, Evapotranspiration of Native 

 Vegetation, Groundwater Subsurface Outflows, 31,445 26,518 20,439

 Natural and Incidental Runoff, Ag Effective 

 Precipitation & Other Outflows

Total 86,909 59,508 40,155

Storage Changes in the Region

[+] Water added to storage

 [-] Water removed from storage 

 Change in Surface Reservoir Storage 2,752 -1,101 -2,412

 Change in Groundwater Storage ** 740 -151 -1,148

 Total 3,492 -1,252 -3,560

Applied Water * (compare with Consumptive Use) 6,957 9,208 9,096

*Footnote for applied water

Consumptive use is the amount of applied water used and no longer available as a source of supply. Applied water is 

 greater than consumptive use because it includes consumptive use, reuse, and outflows. 

**Footnote for change in Groundwater Storage

Change in Groundwater Storage is based upon best available information. Basins in the north part of the 

state (North Coast, San Francisco, Sacramento River and North Lahontan regions and parts of Central 

 Coast and San Joaquin River regions) have been modeled – spring 1997 to spring 1998 for the 1998 

 water year and spring 1999 to spring 2000 for the 2000 water year. All other regions and year 2001 were 

 calculated using the following equation: 

GW change in storage =

 intentional recharge + deep percolation of applied water + conveyance deep percolation - withdrawals

This equation does not include the unknown factors such as natural recharge and subsurface inflow and outflow.

 Water Year (Percent of Normal Precipitation) 

1998 (168%) 2000 (105%) 2001 (67%)

Table 6-2 Sacramento River Hydrologic Region Water Balance Summary - TAF

Water Entering the Region – Water Leaving the Region = Storage Changes in Region

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Chapter 6 Sacramento River Hydrologic Region 6 7

California Water Plan Update 2005

Table 6-3 Sacramento River Region Water Use and Distribution of Dedicated Supplies (TAF)

 Applied Net Depletion Applied Net Depletion Applied Net Depletion

Water Use Water Use Water Use Water Use Water Use Water Use

1998 2000 2001

WATER USE

DEDICATED WATER SUPPLIES

Urban

Large Landscape 91.8 111.2 120.1 

Commercial 113.1 140.4 137.5 

Industrial 77.3 84.2 84.5 

Energy Production 0.0 0.3 0.1 

Residential - Interior 191.5 223.3 229.2 

Residential - Exterior 243.8 291.7 297.3 

Evapotranspiration of Applied Water 313.2 313.2 378.8 378.8 384.4 384.4

E&ET and Deep Perc to Salt Sink 0.2 0.2 0.1 0.1 0.2 0.2

Outflow 312.0 309.4 368.8 366.2 379.6 377.0

Conveyance Applied Water 9.8 8.5 8.5 

Conveyance Evaporation & ETAW 4.9 4.9 4.3 4.3 4.3 4.3

Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Outflow 4.9 4.9 4.2 4.2 4.2 4.2

GW Recharge Applied Water 0.0 0.0 0.0 

GW Recharge Evap + Evapotranspiration 0.0 0.0 0.0 0.0 0.0 0.0

 Total Urban Use 727.3 635.2 632.6 859.6 756.2 753.6 877.2 772.7 770.1

 

Agriculture

On-Farm Applied Water 5,841.2 7,927.1 7,781.7 

Evapotranspiration of Applied Water 3,677.9 3,677.9 4,983.2 4,983.2 4,908.4 4,908.4

E&ET and Deep Perc to Salt Sink 122.0 122.0 173.4 173.4 174.2 174.2

Outflow 1,494.4 497.7 1,901.5 690.3 1,927.7 972.5

Conveyance Applied Water 617.0 786.8 785.4 

Conveyance Evaporation & ETAW 40.6 40.6 61.5 61.5 59.9 59.9

Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

Conveyance Outflow 199.3 139.3 223.7 179.2 232.3 186.9

GW Recharge Applied Water 0.0 0.0 0.0 

GW Recharge Evap + Evapotranspiration 0.0 0.0 0.0 0.0 0.0 0.0

 Total Agricultural Use 6,458.2 5,534.2 4,477.5 8,713.9 7,343.3 6,087.6 8,567.1 7,302.5 6,301.9

 

Environmental

Instream

 Applied Water 3,699.6 3,759.8 3,747.5 

 Outflow 586.3 586.3 600.2 600.2 614.1 614.1

Wild & Scenic

 Applied Water 2,754.1 2,024.7 885.0 

 Outflow 947.7 947.7 782.8 782.8 320.5 320.5

Required Delta Outflow

 Applied Water 9,505.0 7,231.6 4,486.2 

 Outflow 9,505.0 9,505.0 7,231.6 7,231.6 4,486.2 4,486.2

Managed Wetlands

 Habitat Applied Water 398.3 429.5 445.7 

 Evapotranspiration of Applied Water 127.5 127.5 169.7 169.7 162.9 162.9

 E&ET and Deep Perc to Salt Sink 9.8 9.8 14.4 14.4 14.2 14.2

 Outflow 208.2 204.2 193.3 189.1 201.4 197.0

 Conveyance Applied Water 40.8 42.0 23.3 

 Conveyance Evaporation & ETAW 1.9 1.9 1.9 1.9 1.3 1.3

 Conveyance Deep Perc to Salt Sink 0.0 0.0 0.0 0.0 0.0 0.0

 Conveyance Outflow 5.2 5.2 5.2 5.2 2.7 2.7

Total Managed Wetlands Use 439.1 352.6 348.6 471.5 384.5 380.3 469.0 382.5 378.1

 Total Environmental Use 16,397.8 11,391.6 11,387.6 13,487.6 8,999.1 8,994.9 9,587.7 5,803.3 5,798.9

 

TOTAL USE AND OUTFLOW 23,583.3 17,561.0 16,497.7 23,061.1 17,098.6 15,836.1 19,032.0 13,878.5 12,870.9

 

 

Surface Water

 Local Deliveries 13,939.5 13,939.5 13,021.9 12,204.8 12,204.8 11,172.4 8,843.0 8,843.0 8,075.4

 Local Imported Deliveries 9.7 9.7 9.1 10.4 10.4 9.5 8.5 8.5 7.8

 Colorado River Deliveries 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

 CVP Base and Project Deliveries 1,990.7 1,990.7 1,859.7 2,466.7 2,466.7 2,258.0 2,497.3 2,497.3 2,280.5

 Other Federal Deliveries 198.0 198.0 185.0 228.3 228.3 209.0 239.5 239.5 218.7

 SWP Deliveries 14.9 14.9 13.9 14.9 14.9 13.6 19.6 19.6 17.9

 Required Environmental Instream Flow 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Groundwater

 Net Withdrawal 1,408.2 1,408.2 1,408.2 2,173.5 2,173.5 2,173.5 2,270.6 2,270.6 2,270.6

 Deep Percolation of Surface and GW 446.5 641.7 656.3 

Reuse/Recycle

 Reuse Surface Water 5,575.8 5,320.8 4,497.2 

 Recycled Water 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

 

TOTAL SUPPLIES 23,583.3 17,561.0 16,497.7 23,061.1 17,098.6 15,836.1 19,032.0 13,878.5 12,870.9

Balance = Use - Supplies 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

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6 8 Volume 3 Regional Reports

Figure 6-4 Sacramento River region water balance for water years 1998, 2000, 2001

0

5,000

10,000

15,000

20,000

25,000

1998 2000 2001

Thousand Acre-Feet

Wild & Scenic

R.

Instream Flow

Req Delta

Outflow

Managed

Wetlands

Irrigated

Agriculture

Urban

0

5,000

10,000

15,000

20,000

25,000

1998 2000 2001

Thousand Acre-Feet

Reuse &

Recycle

Ground Water

State Project

Federal

Projects

Local Projects

Dedicated Water Supplies

Applied Water Uses

ears 

Three years show a marked change in the amount and relative proportions of water delivered to Sacramento River region’s urban and 

agricultural sectors and water dedicated to the environment (applied water, top chart), where the water came from, and how much 

water was reused among sectors (dedicated water supplies, bottom chart).

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California Water Plan Update 2005

economic growth. Although there is an abundant water supply 

in this hydrologic region, limited infrastructure in the foothill 

communities and the historic water development for the needs 

of the downstream urban and agricultural users has resulted in 

some water supply shortages to outlying and foothill areas in dry 

years. The specific water problems of the foothills are described 

in more detail in Chapter 12 on the Mountain Counties region. 

Urban areas in the central part of this region generally have 

sufficient supplies to survive dry periods with periodic cutbacks. 

However, as future population growth increases in the region, 

the competition for high quality water for municipal water will 

also increase.

Many north valley water users are also concerned that in the 

future their surface water rights may be further curtailed, such 

that more groundwater will be needed for irrigation as well as for 

urban use. In this light, they are apprehensive about new proposals involving the export of surface and groundwater supplies to 

other locations, unless proper planning provides assurances for 

retaining the water necessary to meet future agricultural, urban 

and environmental needs at the local level.

Changes to surface water allocations in the region may occur as 

a result of negotiations for renewal of CVP contracts, increased 

environmental restoration needs, expanded conjunctive use of 

surface and ground water, and various plans and proposals for 

water transfers. Cumulatively, these changes could stimulate a 

substantial increase in groundwater use in the region. In addition 

groundwater development will most likely be targeted to meet a 

significant share of the moderately increasing water demands 

of the region. In response to this phenomenon, some local governments in the region are evaluating the use of groundwater 

regulations in relation to new development as a method to assure 

adequate water supply for future needs.

The potential for developing new supplies from groundwater 

is more favorable in the northern portion of the Sacramento 

Valley. The southern portion is already experiencing localized groundwater supply and quality problems, such as in 

the Sacramento area. Although substantial groundwater can 

potentially be identified in the Sacramento Valley, there is still 

a great deal of research that needs to be done to evaluate the 

quantity and quality of these supplies. If additional groundwater supplies are identified and documented for future use, 

some of the existing groundwater infrastructure might also 

have to be replaced or modified to use the resource to its fullest. Potential environmental impacts of increased groundwater 

extractions in the Sacramento Valley needs to be evaluated 

to determine if this would affect the amount of river surface 

flows and interaction with groundwater tables. 

Competition for use of the groundwater resource is expected to 

continue as population increases, and the potential also exists 

for an increased number of water transfers in the future. Water 

transfers, especially those contracts with a groundwater substitution component, need to be evaluated for their cumulative effects, 

because the overall effect could contribute to greater use of the 

groundwater resources in the region that may negatively impact 

local water users. 

In recent years, requirements for managing threatened and 

endangered species are influencing management of the region’s 

water supplies. The salmon and steelhead fishery in the upper 

Sacramento River has declined greatly over past decades, resulting 

in many programs and projects for fishery restoration. Along the 

Sacramento River, factors that contribute to this problem include: 

unsuitably warm water temperatures, toxic heavy metals from acid 

mine drainage, pesticides and fertilizer runoff, degraded spawning gravels, obstructions to fish migration, and prior destruction 

of riparian habitat due to growth or noxious weed encroachment. 

It should be noted, however, that some riparian habitats are now 

being restored due to projects funded by federal and State agencies 

associated with CBDA (discussed later in this chapter). 

In summary, the majority of the region does enjoy abundant 

groundwater and surface water supplies for all beneficial uses in 

the region. However, precautions should be taken with land use 

changes that may use a greater amount of the natural resources 

because the majority of the area is just beginning to understand 

its groundwater resources and how they, combined with surface 

water supplies, can be used most efficiently.

Challenges

Water Reallocation and Transfers

During extended periods of drought, water districts in the 

Sacramento River Region that rely on surface water supplies 

may be faced with insufficient water supplies, due to surface 

water allocation cutbacks imposed by their CVP and SWP 

water contracts. As shown in Table 6-4, CVP deliveries to this 

region in a normal year exceed 2.4 million acre-feet per year, 

while SWP deliveries in the Feather River service area average 

about 15,000 acre-feet per year. During extended droughts, 

reductions in deliveries could eventually force water users to 

choose between using groundwater to replace the reduced 

surface supplies, or taking valuable agricultural acreage out 

of production. The additional use of groundwater supplies by 

a greater number of water users during droughts may result in 

adverse impacts to the groundwater resource, which has the 

potential to negatively impact users that are totally dependent 

on groundwater supplies. Surface water transfer programs to 

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6 10 Volume 3 Regional Reports

other regions are of concern, because such programs have the 

potential to aggravate overuse of the groundwater resources. 

Before new out-of-basin water transfers are considered, local 

water interests would like to ensure that their existing surface 

water rights are protected, and that equitable use of groundwater supplies are established to sustain the local agricultural 

economy and natural resource needs. 

With a growing demand for high quality water throughout the 

state, water transfers are being evaluated more closely as a 

means to move water out of the Sacramento River region to other 

parts of the state. In response, several counties in the region 

have passed laws that regulate or impede water transfers that 

would move water outside of their county, especially when a 

proposed transfer program has a groundwater component. In 

some counties, for instance, transferees are required to mitigate 

for third-party impacts associated with this type of water transfer 

and transfers require a permit approved by the Board of Supervisors or its designee. In other counties, transferring groundwater 

outside of the county is prohibited by local ordinances.

Water Quality

Surface water quality in the watershed is generally good, 

making the Sacramento River one of the most desirable water 

sources in the state. Nonetheless, turbidity, rice pesticides, and 

organophosphate pesticides such as diazinon affect fisheries 

and drinking water supplies. The decline of fisheries in the 

Sacramento River is in part related to water quality problems on 

the river’s main stem: unsuitable water temperature, toxic heavy 

metals, such as mercury, copper, zinc, and cadmium from acid 

mine drainage, pesticides and fertilizer in agricultural runoff, 

and degraded spawning gravels. Holding of rice field drainage, allowing for degradation or rice herbicides, has effectively 

addressed this water quality concern among downstream water 

users, in particular, the city of Sacramento. In the Cache Creek 

watershed, Clear Lake suffers from large mercury, sediment, and 

nutrient loadings, the latter leading to nuisance algae blooms. 

Along with a few select other water bodies, the basin plan 

specifically prohibits direct discharges of wastes into Folsom 

Lake and the lower American River downstream to its confluence with the Sacramento; waste discharges from houseboats 

on Shasta, Clear Lake, and in the Delta are also banned. High 

density recreation use of Whiskeytown and Shasta lakes may be 

contributing to high bacteria levels in these two reservoirs. 

In its triennial review, the Central Valley Regional Board 

identified mercury loads, a legacy of California’s gold mining 

heritage, as one of the most significant water quality problems 

in the region. In particular, the Cache Creek watershed is the 

major source of mercury to the Delta; to a lesser extent, mercury 

is also a concern in Lake Berryessa and Marsh Creek Reservoir. 

An organic form of mercury, methylmercury, is a neurotoxin 

that is especially dangerous to fetuses and infants, attacking the 

central nervous system and causing an array of developmental 

and other problems. Because of methylmercury’s bioaccumulative properties, several water bodies in the Sacramento River 

region have fish consumption advisories. Pesticide management 

and agricultural water discharge has recently come into the 

limelight with the Central Valley Regional Water Quality Control 

Board’s decision to eliminate waivers associated with agricultural 

discharge. Coalitions in the region are forming partnerships to 

address this issue through a watershed approach as provided 

for by the Regional Board and affirmed by the State Water 

Resources Control Board in their review of the Irrigated Lands 

Conditional Waiver. Stakeholders in the region are working to 

find a solution that encompasses the protection of public health, 

meets current and future water quality regulations, and allows 

for a sustainable agricultural economy. 

Groundwater quality in the Sacramento River Region is generally good, though there are local groundwater problems. 

Naturally occurring salinity impairs wells at the north end of 

the Sacramento Valley. Groundwater near the Sutter Buttes is 

impaired because of local volcanic geology, and hydrogen 

sulfide is a problem in wells in the geothermal areas in the 

western part of the region. Human-induced impairments, like 

nitrate, are generally associated with agriculture and septic 

tanks; the latter is especially an issue in Butte County, where 

150,000 of its 200,000 residents rely upon individual septic 

systems. Septic tanks are often inappropriately sited in shallow, 

unconfined or fractured hard rock aquifers, where insufficient 

soil depth is available for necessary leaching. Heavy metals from 

historical burn dumps also contaminate groundwater locally. In 

the Sierra foothills there is potential for encountering uraniumand radon-bearing rock or sulfide mineral deposits containing 

heavy metals. Perchlorate, previously used as an oxidizer or 

booster for solid rocket fuel and now a human health concern 

in domestic water, has contaminated wells in Rancho Cordova, 

near Sacramento.

Accomplishments

The goals and objectives of the CBDA program play a prominent role in regional efforts to improve water supply reliability, 

water quality and ecosystem restoration. Current activities and 

accomplishments are summarized in the following sections.

Water Supply Reliability

Past concerns with potential groundwater exports have spurred 

numerous counties to enact groundwater ordinances to reguEE-RM-PET-100 C0MMENT 01A
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California Water Plan Update 2005

late groundwater extraction when groundwater is intended 

for export outside the county. In addition, some counties are 

also involved in extensive cataloging and inventory projects 

to determine the extent of their water resources and unmet 

needs of the region to ensure that current and future needs 

are met locally prior to water exports. 

In addition, regional representatives are working in conjunction with CBDA to conduct an extensive reevaluation of 

additional off-stream surface storage reservoirs in this region 

designed to store excess water during high flow events and 

thereby, help alleviate pressure for water exports from the 

region. Water use efficiencies in the region could provide 

benefits to other regions of the state if the storage and conveyance capacity existed to hold and transport water when 

it is needed. This process, commonly known as the North of 

Delta Off-Stream Storage (NODOS) is evaluating previously 

identified sites for their suitability in this type of project. Specifically, the Department of Water Resources is conducting an 

environmental evaluation of the Antelope Valley on the west 

side of the Sacramento River, near Maxwell for the construction 

of off-stream storage currently known as Sites Reservoir. 

Water Use Efficiency

Water use efficiency in the Sacramento Valley is included in a 

comprehensive and integrated program being pursued by the 

agricultural diverters in the region. Most water return flows in 

the region are “recoverable,” which means that water returns 

to rivers and streams where it can be re-used by downstream 

diverters. Because of this, local incentives to improve water use 

efficiency are focused on the benefit of decreased operational 

costs. Water users have accomplished many water saving 

improvements, including laser-leveling of fields to decrease 

water consumption and the lining of canals to reduce subsurface seepage. DWR’s Water Use Efficiency program uses 

grant funding to provide incentives to water users in the 

Sacramento Valley to develop system improvements that will 

make water available for uses that provide statewide benefits. 

These benefits include improving endangered species habitat 

and improving overall water quality throughout the system by 

improving source water quality. 

The recent development of the Sacramento Valley Water 

Management Program (SVWMP) can provide a framework 

for improved regional coordination of water use efficiency 

in the Sacramento Valley. A regional approach to water use 

efficiency allows for the coordination and consolidation of 

individual efforts into a comprehensive plan that optimizes 

limited financial and water resources. The CALFED Bay-Delta 

Program, particularly the approach to the regional Quantifiable Objectives (QOs) articulates this regional approach 

to water use efficiency activities. Additionally, the AB 3616 

Program, and the Central Valley Project Improvement Act 

(CVPIA) Water Conservation Standards could be incorporated 

to develop a unified regional approach to water use efficiency 

for the Sacramento Valley. In the SVWMP, the consolidated 

water use efficiency program would be able to coordinate with 

other program elements to better meet local needs (water user 

and environmental) and potentially provide water for other 

areas of the state. 

Agencies involved in CALFED’s Water Use Efficiency Program, 

including DWR, have accomplished the following results 

through Year 3 of the California Bay Delta Program:

• Partnerships forged for groundwater planning with local 

agencies in six areas. 

• Work initiated on 22 groundwater management and 

groundwater storage projects. 

• Progress made on studies for potential north-of-Delta 

off-stream storage and Shasta Dam enlargement. The 

proposed projects are among five surface storage options 

being studied to increase storage capacity and provide 

flexibility to the state’s water system.

• $11 million in grants awarded for agricultural and urban 

water use efficiency programs. 

• Key achievements made on streamlining water transfers 

and facilitating transfer agreements that protect local 

water users, economies and ecosystems.

Ecosystem Restoration 

Prior to the Gold Rush of the late 1840s, the area known as the 

Sacramento Valley consisted of a warm and abundant natural 

environment, essentially a floodplain to the expansive Sacramento River, rich in natural habitats, such as oaks, sycamore and 

cottonwood. As the Gold Rush subsided, those it brought to California moved into the plains of the Sacramento Valley and began 

ranching and farming, clearing the land for these purposes. As 

the population bases increased in the valley, flood control projects and levees were created in an attempt to control the great 

river to the detriment of the natural processes of the river and 

the species that inhabited it. The CBDA Ecosystem Restoration 

Program attempts to return some of these natural functions to 

the creeks and rivers in the region to aid in the restoration and 

maintenance of the endangered species that once inhabited it. 

Many ecosystem restoration programs and projects are under 

way in the Sacramento River region. Some of these projects are 

along the main stem of the Sacramento River and others involve 

EE-RM-PET-100 C0MMENT 01A
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6 12 Volume 3 Regional Reports

work along or in the tributaries. CBDA Ecosystem Restoration 

and Watershed Programs in the Sacramento River region have 

focused on protecting and restoring habitat for threatened and 

endangered species, such as salmonids and other fish species and 

wildlife. Ecosystem protection and restoration on tributaries of the 

Sacramento River, as well as the main stem, will help to provide 

habitat for these species while also maintaining water quality in 

the source area streams that eventually flow into the Bay-Delta. 

The Sacramento Valley with its alluvial soils, abundant water 

and moderate climate, is one of the richest agricultural regions 

on earth. These same physical attributes also make it an incredibly productive ecosystem that supports more than 250 species 

of fish and wildlife. For example, spring-run Chinook salmon 

swim in from the Pacific and climb 5,000 vertical feet, first 

through the Sacramento River and then Mill Creek, to spawn 

at the base of Lassen Peak. Canada geese fly from north of 

the Artic Circle to winter in the wetlands, and Swainson hawks 

migrate from as far south as Argentina to reach the biologically-rich Sacramento Valley. 

During the past 130 years, more than 95 percent of the valley’s 

historic riparian forests have been converted to other land uses. 

In 1988, federal and state agencies, along with interested 

stakeholders and regional and local nonprofit groups, began to 

stabilize this trend by protecting and restoring riparian habitat 

along the Sacramento River. To date, more than 20,000 acres 

have been protected in such areas as the Sacramento River 

National Wildlife Refuge, the Bureau of Land Management’s 

lands north of Red Bluff, Sacramento River State Wildlife Area, 

other state parks in the region and various areas under private 

conservation ownership. In addition, about 4,000 acres of floodprone agricultural land has been restored to riparian forest. 

In 1986, the Legislature enacted Senate Bill 1086, which called 

for development of a riparian habitat inventory and created the 

Upper Sacramento River Fisheries and Riparian Habitat Management Plan. The purpose of this plan is to preserve remaining 

riparian habitat and reestablish a continuous riparian ecosystem 

along the Sacramento River. The final plan contained a conceptual Riparian Habitat Restoration Plan to guide riparian habitat 

restoration along the river and its major tributaries from Red 

Bluff to Verona. The management plan for this program also 

contained a more specific Fishery Restoration Plan, listing 20 

actions to help restore the salmon and steelhead fisheries of the 

river and its tributaries. All of the proposed restoration is now 

under way, funded by a combination of federal, State, and local 

sources. The Central Valley Project Improvement Act of 1992 

(CVPIA) includes many of the CVP related fishery restoration 

measures recommended by the SB 1086 plan.

One of the concerns expressed by regional stakeholders 

involves land acquisitions for restoration projects that may not 

allow for reimbursement of tax dollars to local governments for 

land conversion projects. Local governments fear that the loss 

of revenue from productive agricultural land taken off of the 

tax roles may affect their ability to provide health and safety 

in their jurisdictions. In response to this concern, since 2000, 

the CBDA has begun using conservation easements rather 

than direct purchases. This approach leaves the property on 

the tax roles, thus minimizing the negative impacts associated 

with land conversion. 

Local governments would also like to see programs that provide 

for species recovery and protection which support reasonable 

recreational access for the public that would contribute to an 

increase in tourism dollars in the local economy. It is anticipated that increased recreation associated with a healthier 

river system will contribute to the local economy in the future. 

The Sacramento River region is the focus of significant CBDA 

ecosystem restoration through several different sources, including local efforts, CVPIA and CBDA, and many more are planned 

for several decades including species recovery of fish. The 

CALFED Multi-species Conservation Strategy (MSCS) is a comprehensive regulatory plan for the CALFED Program developed 

in accordance with the federal Endangered Species Act (ESA), 

the California Endangered Species Act (CESA), and the Natural 

Communities Conservation Planning Act (NCCPA). The MSCS 

establishes the State and federal regulations for numerous species and habitat types throughout the focus area. By adhering 

to this plan, the program can comply with these regulating acts. 

Increased concern over the decline in endangered salmon has 

stimulated several projects and programs in the region over 

the past several years designed to alleviate pressures on these 

fish. Significant work has been accomplished toward this end 

on Butte Creek, for example. Partnerships between landowners 

and agricultural water districts along the creek and State and 

federal agencies have resulted in the removal or reengineering of several small dams, the screening of diversions from this 

creek, and the construction of a canal siphon beneath Butte 

Creek to aid in fish passage for spawning and rearing. These 

partnerships resulted in the removal of the Western Canal, 

McPherrin, McGowan, and Point Four dams and screening 

modification or construction on five other diversions along 

this tributary. These efforts, which have been coordinated and 

partially funded through CBDA, have built strong partnerships in the valley between agencies and landowners. They 

have also contributed to an increase in the returning runs of 

spring-run Chinook salmon, with higher numbers in eight of 

EE-RM-PET-100 C0MMENT 01A
Chapter 6 Sacramento River Hydrologic Region 6 13

California Water Plan Update 2005

the last nine years, compared to the previous two decades. 

These numbers are displayed in the following chart through 

2003 (Figure 6-2). 

Another major salmon recovery project in the Sacramento 

River region is on Battle Creek. The Battle Creek Restoration 

Program proposes to restore access for salmon and steelhead 

to about 42 miles of habitat in the north and south forks of 

Battle Creek while minimizing the reduction of clean and 

renewable energy provided by PG&E’s Battle Creek Hydroelectric Project. This project includes removal of up to five 

diversion dams, construction of ladders and fish screens at 

three additional diversions and increasing flow releases from 

remaining diversion dams. Environmental documents for the 

project are under development and a proposal for additional 

funds is under review by the Ecosystem Restoration Program. 

PG&E is the majority landowner in the project area, and is 

working with the Bureau of Reclamation, USFWS, NOAA Fisheries, Department of Fish and Game under a memorandum 

of understanding signed in 1999. They are working closely 

with the Battle Creek Working Group that includes the Battle 

Creek Watershed Conservancy, other CALFED agencies and 

other interested parties.

A third example of restoration in the Sacramento River region 

lies on Clear Creek, which is also a tributary to the Sacramento River, near Redding in Shasta County. Restoring Clear 

Creek is identified in several significant documents or act of 

legislation, including CVPIA, Section 3406, (b)(12). Through 

increasing flows in the creek by releasing more water from 

Whiskeytown Dam; the removal of McCormick-Saeltzer Dam 

in 2000; supplementing the gravel supply, which was blocked 

by Whiskeytown Dam; implementing methods to control erosion having negative impacts to salmonid habitat; and restoring the stream channel the Clear Creek Restoration Program 

has contributed significantly to the five-fold increase in fall 

Chinook spawning escapements in Clear Creek from 1995 

to 2002 over the baseline period of 1967 to 1991. Data also 

show trends of increases in steelhead and spring-run Chinook 

spawning and juvenile production.

Another major salmon recovery effort in the Sacramento 

River Region is the implementation of the CVPIA Anadromous 

Fish Screen Program. This program has partnered State and 

federal agencies with water diverters in the region to develop 

and implement fish screen projects for the large and significant 

diversions on the Sacramento and other rivers in the regions. 

As a result of this program, almost all of the water diverted from 

the Sacramento River is pumped through state-of-the-art fish 

screens. This program has increased the flexibility of diversions 

from the river, allowing diverters to increase deliveries to wildlife 

refuges, increase the acres of habitat for migratory waterfowl 

using the Pacific Flyway, and implement a valleywide rice straw 

decomposition program that replaces the traditional practice of 

burning rice straw. As a result of these efforts, the Sacramento 

Valley is seeing increases in anadromous fish populations 

without infringements on diversion rights.

In addition to the projects discussed above, another program 

under the ERP which is active in the region is the Environmental 

Water Program (EWP). The goal of this program is to identify 

and purchase 100,000 acre-feet of water annually to augment 

in-stream flows north of the Delta. Four of the five Tier 1 priority streams for the program lie in the region: Clear Creek, Mill 

Creek, Butte Creek and Deer Creek. The EWP is also working 

closely with Battle Creek, which has been identified as a Tier 

2 priority stream in this program. Development of a regional 

implementation structure for the Ecosystem Restoration Program 

Plan that is consistent with and in collaboration with existing 

local restoration program integration efforts is vital. 

There are currently numerous watershed groups in the region 

compiling valuable data and involved in restoration projects in 

their watersheds. However, these are only a piece of the larger 

fabric of the greater Sacramento River watershed. Efforts are 

continuing to provide a comprehensive view of the watershed 

based on information gathered from funded projects throughout 

the watershed. This will allow for more informed decisionmaking and better protection and use of the resources.

Through Year 3 of the CBDA Program, the Ecosystem Restoration 

Program (ERP) and CALFED Watershed program have provided 

funding to the Sacramento Valley region as follows:

• $172 million invested in 139 local ecosystem restoration projects. Funded projects, including more than 50 

projects to improve fish passage, restore habitat, monitor and assess watersheds, and provide education and 

outreach.

• $11.4 million invested in 40 local watershed projects 

addressing areas such as spawning gravel, floodplain 

management and watershed education and outreach.

• $12 million provided for studies addressing mercury and 

other pollutants associated with abandoned mines. 

Looking to the Future

Water agencies in the region continue to manage water in 

light of changing conditions in the region and the state. An 

example is the Sacramento Valley Water Management Program (SVWMP). This resource management program was 

EE-RM-PET-100 C0MMENT 01A