Flood control, energy production, and water conveyance infrastructure in California
The Central Valley Project (CVP) is a federal power and water management project in the U.S. state of California under the supervision of the United States Bureau of Reclamation (USBR). It was devised in 1933 in order to provide irrigation and municipal water to much of California's Central Valley—by regulating and storing water in reservoirs in the northern half of the state (once considered water-rich but suffering water-scarce conditions more than half the year in most years), and transporting it to the water-poor San Joaquin Valley and its surroundings by means of a series of canals, aqueducts and pump plants, some shared with the California State Water Project (SWP). Many CVP water users are represented by the Central Valley Project Water Association.
In addition to water storage and regulation, the system has a hydroelectric capacity of over 2,000 megawatts, and provides recreation and flood control with its twenty dams and reservoirs. It has allowed major cities to grow along Valley rivers which previously would flood each spring, and transformed the semi-arid desert environment of the San Joaquin Valley into productive farmland. Freshwater stored in Sacramento River reservoirs and released downriver during dry periods prevents salt water from intruding into the Sacramento-San Joaquin Delta during high tide. There are eight divisions of the project and ten corresponding units, many of which operate in conjunction, while others are independent of the rest of the network. California agriculture and related industries now directly account for 7% of the gross state product for which the CVP supplied water for about half.
Many CVP operations have had considerable environmental consequences, including a decline in the salmon population of four major California rivers in the northern state, and the reduction of riparian zones and wetlands. Many historical sites and Native American tribal lands have been flooded by CVP reservoirs. In addition, runoff from intensive irrigation has polluted rivers and groundwater. The Central Valley Project Improvement Act, passed in 1992, intends to alleviate some of the problems associated with the CVP with programs like the Refuge Water Supply Program.
In recent years, a combination of drought and regulatory decisions passed based on the Endangered Species Act of 1973 have forced Reclamation to turn off much of the water for the west side of the San Joaquin Valley in order to protect the fragile ecosystem in the Sacramento-San Joaquin Delta and keep alive the dwindling fish populations of Northern and Central California rivers. In 2017 the Klamath and Trinity rivers witnessed the worst fall run Chinook salmon return in recorded history, leading to a disaster declaration in California and Oregon due to the loss of the commercial fisheries. The recreational fall Chinook salmon fishery in both the ocean and the Trinity and Klamath rivers was also closed in 2017. Only 1,123 adult winter Chinook salmon returned to the Sacramento Valley in 2017, according to a report sent to the Pacific Fishery Management Council (PFMC) by the California Department of Fish and Wildlife (CDFW). This is the second lowest number of returning adult winter run salmon since modern counting techniques were implemented in 2003. By comparison, over 117,000 winter Chinooks returned to spawn in 1969.
Overview.
Operations.
The CVP stores about of water in 20 reservoirs in the foothills of the Sierra Nevada, the Klamath Mountains and the California Coast Ranges, and passes about of water annually through its canals. Of the water transported, about goes to irrigate of farmland, supplies municipal uses, and is released into rivers and wetlands in order to comply with state and federal ecological standards.
Two large reservoirs, Shasta Lake and Trinity Lake, are formed by a pair of dams in the mountains north of the Sacramento Valley. Water from Shasta Lake flows into the Sacramento River which flows to the Sacramento-San Joaquin Delta and water from Trinity Lake flows into the Trinity River which leads to the Pacific Ocean. Both lakes release water at controlled rates. There, before it can flow on to San Francisco Bay and the Pacific Ocean, some of the water is intercepted by a diversion channel and transported to the Delta-Mendota Canal, which conveys water southwards through the San Joaquin Valley, supplying water to San Luis Reservoir (a SWP-shared facility) and the San Joaquin River at Mendota Pool in the process, eventually reaching canals that irrigates farms in the valley. Friant Dam crosses the San Joaquin River upstream of Mendota Pool, diverting its water southwards into canals that travel into the Tulare Lake area of the San Joaquin Valley, as far south as the Kern River. Finally, New Melones Lake, a separate facility, stores water flow of a San Joaquin River tributary for use during dry periods. Other smaller, independent facilities exist to provide water to local irrigation districts.
Background.
The Central Valley Project was the world's largest water and power project when undertaken during Franklin D. Roosevelt's New Deal public works agenda. The Project was the culmination of eighty years of political fighting over the state's most important natural resource - Water. The Central Valley of California lies to the west of the Sierra Nevada Mountains with its annual run-off draining into the Pacific Ocean through the Sacramento–San Joaquin River Delta. It is a large receding geological floodplain moderated by its Mediterranean climate of dry summers and wet winters that includes regular major drought cycles. At the time of its construction, the project was at the center of a political and cultural battle over the state's future. It intersected with the state's ongoing war over land use, access to water rights, impacts on indigenous communities, large vs. small farmers, the state's irrigation districts and public vs. private power. Its proponents ignored environmental concerns over its impacts, other than the outcome not damage the major stakeholders at that time.
The Central Valley of California has gone through two distinct culturally driven land use eras. The first was the indigenous tribal period that lasted for thousands of years. Then came the arrival of Europeans, first by the Spanish colonial model of Catholic missions and ranchos (1772–1846) was then followed by the current United States era. Due to its Mediterranean climate, the first cultural period was hunter-gatherer based. The Spanish missions' ranching and tanning business was based on the forced labor of Las Californias tribes. Spain's model of land use with the grazing of livestock for meat, wool and leather started along Alta California's coast eventually spreading inland. The U.S. era evolved from primarily ranching to large-scale plantations or more commonly known today as corporate farming that turned the Central Valley into the breadbasket of the U.S.
Following the 1848 California Gold Rush, large numbers of U.S. citizens came into the region and made attempts to practice rainfed agriculture, but most of the Central Valley land was taken up by large cattle ranchers like Henry Miller who eventually controlled 22,000 square miles of land. The large-scale levee construction by Chinese workers along the Delta was where limited irrigation for orchards first started.
Following the arrival of the Transcontinental railroad, immigration from Asia and the rest of the U.S. led to growing numbers of settlers in the region. Despite the rich soils and favorable weather of the Central Valley, immigrants to the valley who were unfamiliar with its seasonal patterns of rainfall and flooding began to take up irrigation practices. Farmers soon found themselves troubled by frequent floods in the Sacramento Valley and a general lack of water in the San Joaquin Valley. The Sacramento River, which drains the northern part, receives between 60 and 75% of the precipitation in the Valley, despite the Sacramento Valley covering less area than the much larger San Joaquin Valley, drained by the San Joaquin River, which receives only about 25% of the rainfall. Furthermore, cities drawing water from the Sacramento-San Joaquin Delta faced problems in dry summer and autumn months when the inflowing water was low. In order to continue to sustain the valley's economy, there needed to be systems to regulate flows in the rivers and equally distribute water among the north and south parts of the valley.
History.
In 1873, Barton S. Alexander completed a report for the U.S. Army Corps of Engineers that was the first attempt at creating a Central Valley Project. In 1904, the Bureau of Reclamation (then the Reclamation Service) first became interested in creating such a water project, but did not get far involved until a series of droughts and related disasters occurred in the early 1920s. The State of California passed the Central Valley Project Act in 1933, which authorized Reclamation to sell revenue bonds in order to raise about $170 million for the project. Unfortunately, because of insufficient money in the state's treasury and the coincidence with the Great Depression, California turned to the national government for funding to build the project. This resulted in several transfers of the project between California and the federal government, and between Reclamation and the Army Corps of Engineers. The first dams and canals of the project started going up in the late 1930s, and the last facilities were completed in the early 1970s. Other features of the project were never constructed, some lie partly finished, or are still awaiting authorization.
Facilities in the Sacramento Valley.
Sacramento River.
Shasta Division consists of a pair of large dams on the Sacramento River north of the city of Redding. The Shasta Dam is the primary water storage and power generating facility of the CVP. It impounds the Sacramento River to form Shasta Lake, which can store over of water, and can generate 680 MW of power. Shasta Dam functions to regulate the flow of the Sacramento River so that downstream diversion dams and canals can capture the flow of the river more efficiently, and to prevent flooding in the Sacramento-San Joaquin Delta where many water pump facilities for San Joaquin Valley aqueducts are located. The Keswick Dam functions as an afterbay (regulating reservoir) for the Shasta Dam, also generating power.
The Sacramento Canals Division of the CVP takes water from the Sacramento River much farther downstream of the Shasta and Keswick Dams. Diversion dams, pumping plants, and aqueducts provide municipal water supply as well as irrigation of about . The Red Bluff Diversion Dam diverts part of the Sacramento River into the Tehama-Colusa Canal, the Corning Canal and a small reservoir formed by Funks Dam. Six pump plants take water from the canal and feed it to the Colusa County water distribution grid.
Trinity River.
Water diversions from northern rivers in the state remain controversial due to environmental damage. Trinity River Division is the second largest CVP department for the northern Sacramento Valley. The primary purpose of the division is to divert water from the Trinity River into the Sacramento River drainage downstream of Shasta Dam in order to provide more flow in the Sacramento River and generating peaking power in the process. Trinity Dam forms Trinity Lake, the second largest CVP water-storage reservoir, with just over half the capacity of Shasta and a generating capacity of 140 MW. Lewiston Dam, downstream of Trinity Dam, diverts water into the Clear Creek Tunnel, which travels to empty into a third reservoir, Whiskeytown Lake on Clear Creek, a tributary of the Sacramento River, generating 154 MW of power in the process. Whiskeytown Lake (formed by Clair. A Hill Whiskeytown Dam) in turn provides water to the Spring Creek Tunnel, which travels into the lowermost extreme of Spring Creek, a stream that flows into Keswick Reservoir, generating another 180 MW of electricity. From there the water from the Trinity River empties into Keswick Reservoir and the Sacramento River. In 1963, the Spring Creek Debris Dam was constructed just upstream of the outlet of the Spring Creek Tunnel, to prevent acid mine drainage from the Iron Mountain Mine from continuing downstream and contaminating the river.
American River.
The American River Division is located in north-central California, on the east side of the Great Central Valley. Its structures use the water of the American River, which drains off the Sierra Nevada and flows into the Sacramento River. The division is further divided into three units: the Folsom, Sly Park and Auburn-Folsom South. The American River Division stores water in the American River watershed, to both provide water supply for local settlements, and supply it to the rest of the system. The dams also are an important flood control