California’s interconnected water system serves over 30 million people and irrigates over 5,680,000 acres (2,300,000 ha) of farmland. As the world’s largest, most productive, and most controversial water system,[1] it manages over 40,000,000 acre feet (49 km3) of water per year.[2]
Contents |
California’s water supply comes from two sources: surface water, or water that travels or gathers on the ground, like rivers, streams, and lakes; and groundwater, which is water that is pumped out from the ground.
While few often think of the water beneath the surface of the Earth, it is an important element of the water cycle. Water that falls as rain, and then is absorbed into the ground will generally make its way to the water table, or “aquifer”. It is this water from the aquifer that is pumped out of the ground to be used for human purposes. Groundwater is a critical element of the California water supply. During an average year, 40% of the state’s water supply comes from groundwater. In times of intense drought, groundwater consumption can rise to 60% or more.[3] Over 850,000,000 acre feet (1,050 km3) of water, enough to cover California to a depth of 8 feet (2 m) is stored in California’s 450 known groundwater reservoirs.[3] However, not all the water is usable. Over half of the groundwater is unavailable due to poor quality and the high cost of pumping the water from the ground. While surface water is concentrated mostly in the northern part of the state, groundwater is more evenly distributed.
The largest groundwater reservoirs are found in the Central Valley.[3] The majority of the supply there is in the form of runoff that seeps into the aquifer. The freshwater is usually found in deposits of gravel, silt, and sand. Below these deposits lies a layer of deep sediment, a relic of the era when the Pacific Ocean covered the area.
Though California has laws governing surface water usage and quality, there exist no statewide groundwater management laws. Each groundwater basin is individually adjudicated to determine water rights. [4] Otherwise, for all practical purposes, land ownership implicitly carries the right to virtually unlimited groundwater pumping.
The large quantity of water beneath the surface has given rise to the misconception that groundwater is a sort of renewable resource that can be limitlessly tapped. While the volume of groundwater is very large, aquifers can be over drafted when groundwater is removed more rapidly than it is replenished. On average, annual over drafting is around 2,200,000 acre feet (2.7 km3) across the state, with 800,000 acre feet (0.99 km3) in the Central Valley.[5] The assumption that groundwater usage is sustainable if the rate of removal equals the rate of recharge is often not correct, because these assumptions often ignore changes in water consumption and water renewal.[6]
California has ten major drainage basins defined for convenience of water management. These basins are divided from one another by the crests of mountains. From north to south the basins are: North Coast, Sacramento River, North Lahontan, San Francisco Bay, San Joaquin River, Central Coast, Tulare Lake, South Lahontan, South Coast, and Colorado River regions. Each region incorporates watersheds from many rivers of similar clime.
| Hydrologic region | Annual precipitation | Annual runoff |
|---|---|---|
| North Coast | 55,900,000 acre feet (69.0 km3) | 28,900,000 acre feet (35.6 km3) |
| Sacramento River | 52,400,000 acre feet (64.6 km3) | 22,400,000 acre feet (27.6 km3) |
| North Lahontan | 6,000,000 acre feet (7.4 km3) | 1,900,000 acre feet (2.3 km3) |
| San Francisco Bay | 5,500,000 acre feet (6.8 km3) | 1,200,000 acre feet (1.5 km3) |
| San Joaquin River | 21,800,000 acre feet (26.9 km3) | 7,900,000 acre feet (9.7 km3) |
| Central Coast | 12,300,000 acre feet (15.2 km3) | 2,500,000 acre feet (3.1 km3) |
| Tulare Lake | 13,900,000 acre feet (17.1 km3) | 3,300,000 acre feet (4.1 km3) |
| South Lahontan | 9,300,000 acre feet (11.5 km3) | 1,300,000 acre feet (1.6 km3) |
| South Coast | 10,800,000 acre feet (13.3 km3) | 1,200,000 acre feet (1.5 km3) |
| Colorado River | 4,300,000 acre feet (5.3 km3) | 200,000 acre feet (0.25 km3) |
Around 75% of California’s water supply comes from north of Sacramento, while 80% of the water demand occurs in the southern two-thirds of the state.[7] The majority of California water is used by the agricultural industry. About 80-85% of all California water is used for agricultural purposes. This water irrigates almost 29 million acres (120,000 km2), on which grow 350 different crops.[8] Urban users consume 10% of the water, or around 8,700,000 acre feet (10.7 km3).[9] Industry receives the remnant of the water supply.[10]
There are six main systems of aqueducts and infrastructure that redistribute and transport water in California: the State Water Project, the Central Valley Project, several Colorado River delivery systems, the Los Angeles Aqueduct, the Tuolumne River/Hetch Hetchy system, and the Mokelumne Aqueduct.
The California State Water Project is the largest multipurpose, state-built water project in the United States.[11] The SWP transports water from the Feather River watershed to agriculture, and some of the water goes to industrial and urban users. More than two-thirds of Californians receive some water from the SWP. In an average year the SWP delivers 2,300,000 acre feet (2.8 km3), but the system has over committed and contracted to deliver 4,200,000 acre feet (5.2 km3).[3] Twenty-nine agencies hold contracts for SWP water. The contractors pay for SWP’s major operating costs and have gradually reduced the $1.75 billion bond debt that supplied funds for initial construction. In the years since 1960, SWP has built 29 dams, 18 pumping plants, five hydroelectric power plants, and around 600 miles (970 km) of canals and pipelines.[3]
The SWP system begins with reservoirs on upper tributaries of the Feather River. Oroville Dam creates the largest SWP reservoir. At 770 feet (230 m) above the riverbed, the dam is the tallest in the United States. The reservoir covers 15,000 acres (61 km2) and holds 3,500,000 acre feet (4.3 km3).[12] Water travels from Lake Oroville to the Sacramento River. At Harvey O. Banks Delta Pumping Plant, which pulls SWP water into the Bethany Reservoir, around 2,200,000 acre feet (2.7 km3) are extracted from the Delta each year.[13] Water that flows to the south end of the San Joaquin Valley must be pumped over the Tehachapi Mountains. Because of this, the SWP is California’s largest energy consumer, and even though the hydroelectric plants of the SWP generate 5900 GWh per year, that is only a fraction of the energy needed to lift water over the Tehachapis.[14] Below the Tehachapis the California Aqueduct splits, with the west branch storing water in Castaic and Pyramid Lake, and the east branch storing water in the Silverwood Lake reservoir.
The CVP’s original purpose was to tame seasonal flooding and to direct water to the south to irrigate 3 million acres (12,000 km2) of farmland. The CVP is operated by the United States Bureau of Reclamation. As one of the largest water systems in the world it stores over 7,000,000 acre feet (8.6 km3) of water, or 17 percent of the state’s developed water.[15] The CVP dams and diverts five major rivers: the Trinity, the Sacramento, the American, the Stanislaus, and the San Joaquin. Friant Dam, on the San Joaquin, was completed in 1944, forming Millerton Lake. This was one of 20 reservoirs in the CVP. Shasta Dam, the largest CVP storage facility, was completed in 1945. At Sacramento, American River water stored by Folsom Dam is added. 2,500,000 acre feet (3.1 km3) are annually pumped from the Delta into the Delta-Mendota Canal. New Melones Dam on the Stanislaus River was finished in 1979, and the reservoir was filled in 1982.
The CVP has generated some controversy about environmental damage, prices charged to farmers, and lax enforcement of farm size limitations. Bureau of Reclamation water was supposed to be used for farms limited to 160 acres (see Homestead Act). Under Spanish and Mexican land grants, however, there were only a few land owners, all of whom owned large tracts of land. A 1982 reform increased CVP area limits to 960 acres (3.9 km2).[16] In 1992, the Central valley Project Improvement Act made fish and wildlife protection and restoration the primary purposes of the CVP. 800,000 acre feet (0.99 km3) of annual runoff were dedicated to environmental usage, which generated intense controversy.[17] The diversion of the San Joaquin by the CVP made it impossible for over 100,000 salmon to reach spawning grounds.[18]
The Colorado River is the source of 4,400,000 acre feet (5.4 km3) per year for California.[19] Six other states along the river’s watershed (Wyoming, Nevada, Utah, Colorado, New Mexico, and Arizona) and Mexico, share allocated portions of river water. The Metropolitan Water District of Southern California, or MWD, holds priority water rights on the Colorado. It sells water to 95 percent of the South Coast region. Lake Mead, formed by Hoover Dam, is the primary reservoir in the Colorado River basin. The Colorado River Aqueduct begins 155 miles (249 km) downstream from Hoover Dam, and can carry 1,200,000 acre feet (1.5 km3) annually.
The Colorado is often over allocated, because apportionments were made on inaccurate measurements of annual runoff. Marc Reisner in ‘’Cadillac Desert’’ said the Colorado is "unable to satisfy all the demands on it, so it is referred to as a ‘deficit’ river, as if the river were somehow at fault for its overuse."[20] For years California took more than its share of the apportionment, because other states were not prepared to use their entire allotments. MWD became used to 800,000 acre feet (0.99 km3) excess of water. Pressure from other Colorado river states caused the Secretary of the Interior to order California to show progress towards decreasing its dependency on the excess 800,000 acre feet (0.99 km3), or face cuts.[3] The Colorado River Water Use Plan called for Imperial and Coachella Valley agriculture to give up water in order to reallocate 800,000 acre feet (0.99 km3) within the state. The plan’s proposals generated much controversy, and the deadline arrived with no agreement reached. The Department of the Interior reduced MWD’s access by 415,000 acre feet (0.512 km3).
The Los Angeles Aqueduct carries water from the Eastern Sierra Nevada to Los Angeles. The construction of the aqueduct marked the first major water delivery project in California. The city purchased 300,000 acres (1,200 km2) of land in the Owens Valley in order to gain access to water rights. (See: California Water Wars) The Los Angeles Department of Water and Power transports 400,000 acre feet (0.49 km3) of Eastern Sierra Nevada water to the city each year. This growth clearly shows William Mulholland’s observation that “Whoever brings the water, brings the people.”[21]
After four decades of diversion from the Mono Lake area, environmental damage created an environmental battle in the 1980s, with a victory for the Mono Lake proponents in 1994.[22] Other problems arose when dust from the bed of Owens Lake (completely dried up by diversions) became a major source of air pollution in the southern Owens Valley. To restore Mono Lake, correct air-quality law violations, and rewater portions of the Owens River, Los Angeles has begun to reduce its dependence on Eastern Sierra Nevada water. This has mostly been achieved through water conservation. The city enacted a program offering free low-flow toilets to its customers.[23]
The Hetch Hetchy Aqueduct carries water from the Tuolumne River to San Francisco and other Bay Area regions. The system starts in Hetch Hetchy Valley, inside Yosemite National Park. The system also generates electricity, which is a major source of revenue for San Francisco. After water leaves Hetch Hetchy, it passes through tunnels towards powerhouses. Three pipes then bring the water across the Central Valley. Concerns about the Hetch Hetchy Aqueduct’s ability to withstand earthquakes led to a $1.7 billion bond, approved by voters in November 2002.[24]
The East Bay Municipal Utility District (EBMUD) serves 35 communities in Alameda and Contra Costa Counties, including Berkeley and Oakland. The Mokelumne River in the central Sierra Nevada is the source for almost all of EBMUD’s water. EBMUD built the Pardee Dam across the Mokelumne in the foothills northeast of Stockton. South of Pardee is Camanche Reservoir, which regulates releases to serve downstream water rights holders. EBMUD holds almost 30,000 acres (120 km2) in the Mokulumne River watershed and 25,000 acres (100 km2) in other watersheds. EBMUD also has an American River water right that could be sent to the Mokelumne Aqueduct through the Folsom South Canal. The only time this has been done was during the drought years of 1977-78, when the water was actually pumped from the Delta.[3] This generated controversy, as EBMUD preferred the cleaner water from the American River, but environmentalists and Sacramento had concerns about the impacts such a diversion would have on the river. The legal battle led to affirmation of EBMUD’s water right, but modifications were also negotiated. The intake point was moved downstream, to maintain minimum flows in the American River before it merges with the Sacramento.
Certain municipalities north of San Francisco Bay, including Santa Rosa and Petaluma, are served by the Sonoma County Water Agency. Their primary water source is the Russian River.
The cities of Vallejo, Fairfield, and Vacaville are served by the Solano County Water Agency, which transports water from Lake Berryessa and moves it south along the Putah South Canal. Marin County has the Marin Municipal Water District and the North Marin Water District.
On more than one occasion, the California Supreme Court has noted that “[t]he scope and technical complexity of issues concerning water resource management are unequalled by virtually any other type of activity presented to the courts."[25][26] An example of this complexity is demonstrated in the case of National Audubon Society v. Superior Court.
Water rights are divided in multiple ways. Water rights to surface water and underground sources are separate. Also, California recognizes four distinct types of water rights to surface water in its statutory and common law: pueblo, riparian, prior appropriation, and water reserved by the U.S. A fifth statutory right also provides area of origin watershed rights.
California recognizes water rights granted to pueblos (settlements) under the Spanish and Mexican governments, prior to the Treaty of Guadalupe Hidalgo.[27][28] Pueblos organized under the laws of Mexico or Spain have a water right to all streams and rivers flowing through the city and to all groundwater aquifers underlying the city.[29] Pueblo water rights are superior to all riparian and appropriative rights and cannot be lost by a failure to assert an interest or use the water.[30] In addition, the pueblo's claim expands with the needs of the city and may be used to supply the needs of areas that are later annexed to the city.[30] Los Angeles and San Diego are the only original pueblos to exercise their pueblo water rights in the courts.
Under the riparian doctrine, "the owner of land has the right to divert the water flowing by his land for use upon his land, without regard to the extent of such use or priority in time."[31] "[R]iparians on a stream system are vested with a common ownership such that in times of water shortage all riparians must reduce their usage proportionately."[32] To accommodate gold mining, the doctrine of appropriation was incorporated into California water law. Riparian rights, however, continue to be acquired through ownership of land contiguous to the watercourse.[32]
“The appropriation doctrine confers upon one who actually diverts and uses water the right to do so provided that the water is used for reasonable and beneficial uses,” regardless of whether that person owns land contiguous to the watercourse.[32] In addition, all appropriative rights are subordinate to riparians or earlier appropriators.[32] In times of shortage riparians are entitled to fulfill their needs before appropriators are entitled to any use of the water.[33] "And, as between appropriators, the rule of priority is 'first in time, first in right.'"[34] Beginning in 1914, a statutory scheme has provided the exclusive method of acquiring appropriation rights through the California State Water Resources Control Board. [35] The modern system of prior appropriation water rights followed by California is characterized by five principles:
Beneficial use is defined as agricultural, industrial, or urban use. Environmental uses, such as maintaining body of water and the wildlife that use it, were not initially regarded as beneficial uses in some states but have been accepted in some areas.[37] Every water right is parameterized by an annual yield and an appropriation date. When a water right is sold, it maintains its original appropriation date.
Lands reserved by the United States government are accompanied by a corresponding reservation of water rights for as much water is needed to fulfill the purpose for which the reservation was made. Such reservations were made on behalf of native American tribes,[38][39] national parks, monuments,[40] and forests. Water rights reserved by the United States are defined by and controlled by federal law. And because reserved water rights are not riparian nor appropriative, they may conflict with state law.[40]
California provides communities and other water users within watersheds senior status over appropriative water rights in limited circumstances.[41]
Area of origin water rights parallel pueblo water rights. In both cases, water is reserved for future growth of the local community. In other words, appropriations may be subject to a water rights claim from people/government in the area of origin. That later claim would be senior despite its temporal disconnect. As a result of its pueblo rights, Los Angeles has rights to all or almost all water from the Los Angeles River. In the same way, communities along major water sources such as the Sacramento River theoretically have senior water rights to support growth despite a downstream user holding otherwise senior appropriative water rights.
Area of origin laws were passed in reaction to the controversies related to Los Angeles diverting water from the Owens Valley. Despite being on the books for generations, the area of origin statutes were not used until 2000. In addition, there currently are no court opinions regarding area of origin watershed rights.
It is projected that California’s population will be almost 50 million people in the year 2020.[42] If the prediction comes true and there is no action to increase the water supply, the difference between water demand and supply would be between 2 and 6,000,000 acre feet (7.4 km3) in the year 2020.[43] Already, the effects of long-term drought in the Central Valley helped to push unemployment up to 40% in 2009, and agricultural revenue losses are almost $500 million.[44] Over the past 5 years California voters have approved $3 billion in bonds for water development and management. Many of these projects are incorporated in the CALFED Bay-Delta program, a federal-state program designed to reduce water supply conflicts. In August 2000 the state and federal governments approved the CALFED plan for water quality, water conservation and recycling, watershed administration, ecosystem re-establishment, delta levees, surface and groundwater storage, water transportation, and science. The plan has a 30-year implementation period and designed to incorporate changes in conditions and knowledge about the effects of specific projects. Stage 1 was initiated in 2000 and was designed as a 7-year program. The cost is estimated to be $8.7 billion.[45] Stage 1 water yield within the next 7 to 10 years is estimated to be 2,900,000 acre feet (3.6 km3) per year.[43] As part of Stage 1, an Environmental Water Account was established through the purchase of 350,000 acre feet (0.43 km3) of water. The EWA is used to protect fish and other wildlife without reducing water allocations to farms and municipalities.
The California Water Wars, a struggle between Los Angeles and the Owens Valley for water rights, is one of the most well-known examples of the lengths people will go to in order to secure adequate water supplies. The city of Los Angeles bought 300,000 acres (1,200 km2) of land in the Owens Valley, and thus obtained water rights for a good deal of the water there. The diverting of so much water from the valley transformed it from an agricultural valley into a dust bowl.[20]
The O'Shaughnessy Dam was the subject of controversy when it was reported by the San Francisco Bay Guardian that the city of San Francisco sold roughly 500 megawatts of power to the PG&E,[46] supposedly in violation of the Raker Act, which specifies that because the source of water and power was on public land, no private profit could be gained from the dam. Whether or not the Raker Act is indeed being violated is still a matter of controversy.
The creation of so many dams in California in order to enact a pragmatic water supply program has been met with criticism from some environmentalists, who have decried the negative effects of dams on ecosystems, particularly on migratory fish populations.[47]
The California Water Documents collection in the Claremont Colleges Digital Library is a valuable online resource of archived materials related to California’s water history. Topics encompassed in the collection include: water quality, flood control, water distribution, water conservation, water usage, drought, and geology.[48] Additionally, the collection has digitized materials relating to the creation and operation of both the Central Valley Project and the California State Water Project as well as their component units.[48] The items represented in the Claremont Colleges Digital Library are part of a larger collection entitled the Water Resources Collection in Special Collections at Claremont Colleges’ Honnold/Mudd Library. The Water Resources Collection was started in the 1930s by Librarian Willis Holmes Kerr and Librarian and Claremont Colleges’ Trustee John Treanor.[49] These librarians’ interest in California’s water problem led them to start collecting a variety of documents related to water history and usage from around the state. It includes reports of engineers, annual reports and minute books of boards of directors of water companies, documents of federal and state governments, promotional pamphlets, and newspaper clippings.[49] Most of the documents focus on the water history from the first half of the 20th century, but there are additional, more recent publications included, which have been donated by Claremont Graduate University Professor Merrill Goodall.[49] The California Water Documents collection is currently a work in progress at the Claremont Colleges Digital Library.