California Aqueduct

The aqueduct serves 35 million people and 5.7 million acres of farmland, and begins at the San Joaquin-Sacramento River Delta at the Banks Pumping Plant, which pumps from the Clifton Court Forebay. Water is pumped by the Banks Pumping Plant to the Bethany Reservoir. The reservoir serves as a forebay for the South Bay Aqueduct via the South Bay Pumping Plant. From the Bethany Reservoir, the aqueduct flows by gravity approximately to the O'Neill Forebay at the San Luis Reservoir. From the O'Neill Forebay, it flows approximately to the Dos Amigos Pumping Plant. After Dos Amigos, the aqueduct flows about to where the Coastal Branch splits from the "main line". The split is approximately south-southeast of Kettleman City. After the coastal branch, the line continues by gravity another to the Buena Vista Pumping Plant. From the Buena Vista, it flows approximately to the Teerink Pumping Plant. After Teerink it flows about to the Chrisman Pumping Plant. Chrisman is the last pumping plant before Edmonston Pumping Plant, which is from Chrisman. South of the plant the west branch splits off in a southwesterly direction to serve the Los Angeles Basin. At Edmonston Pumping Plant it is pumped over the Tehachapi Mountains. Water flows through the aqueduct in a series of abrupt rises and gradual falls. The water flows down a long segment, built at a slight grade, and arrives at a pumping station powered by Path 66 or Path 15. The pumping station raises the water, where it again gradually flows downhill to the next station. However, where there are substantial drops, the water's potential energy is recaptured by hydroelectric plants. The initial pumping station fed by the Sacramento River Delta raises the water , while a series of pumps culminating at the Edmonston Pumping Plant raises the water over the Tehachapi Mountains. A typical section has a concrete-lined channel at the base and an average water depth of about . The widest section of the aqueduct is and the deepest is . Channel capacity is and the largest pumping plant capacity at Dos Amigos is . A 2021 study published in Nature Sustainability estimated that the installation of solar panels over the canal could potentially reduce annual water evaporation by of canal. While electricity generated by the solar panels could be used by the aqueduct's pumping systems, the study also considered the possibility of supplying power to irrigation systems in the Central Valley to reduce reliance on diesel-powered irrigation pumps. Similar canal-spanning solar installations have been demonstrated in India, including a steel truss design in Gujarat and a suspension cable design in Punjab. ==Branches==

From its beginning until its first branch, the aqueduct passes through parts of Contra Costa, Alameda, San Joaquin, Stanislaus, Merced, Fresno, and Kings counties. The aqueduct then divides into three branches: the Coastal Branch in the Central Valley, and the East and West Branches after passing over the Tehachapi Mountains. Coastal Branch The Coastal Branch splits from the main line south-southeast of Kettleman City transiting Kings County, Kern County, San Luis Obispo County, and Santa Barbara County to deliver water to the coastal cities of San Luis Obispo, Santa Maria, and Santa Barbara. The Coastal Branch is and has five pump stations. Phase I, an above-ground aqueduct totaling from where it branches from the California Aqueduct, was completed in 1968. With construction beginning in 1994, Phase II consists of of a diameter buried pipeline extending from the Devils Den Pump Plant, and terminates at Tank 5 on Vandenberg Space Force Base in Santa Barbara County. The Central Coast Water Authority (CCWA) extension, completed in 1997, is a (30–39 in) (76–99 cm) diameter pipeline that travels from Vandenberg through Vandenberg Village, Lompoc, Buellton, and Solvang where it terminates at Lake Cachuma in Los Padres National Forest. Coastal Branch facilities include: • Las Perillas Pumping Plant • Badger Hill Pumping Plant • Devil's Den Pumping Plant • Bluestone Pumping Plant • Polonio Pass Pumping Plant • Polonio Pass Water Treatment Plant • Cuesta Tunnel • Santa Ynez Pumping Facility East Branch The aqueduct splits off into the East Branch and West Branch in extreme southern Kern County, north of the Los Angeles County line. The East Branch supplies Lake Palmdale and terminates at Lake Perris, in the area of the San Gorgonio Pass. It passes through parts of Kern, Los Angeles, San Bernardino, and Riverside counties. East Branch facilities include: • Tehachapi East Afterbay • Alamo Power Plant • Pearblossom Pumping Plant • Mojave Siphon • Mojave Siphon Power Plant • Cedar Springs Dam • Silverwood Lake • San Bernardino Intake Structure • San Bernardino Tunnel • Devil Canyon Power Plant • Devil Canyon Afterbay 1 and Afterbay 2 • Greenspot Pump Station (Backup) • Citrus Reservoir • Citrus Pump Station • Crafton Hills Reservoir • Crafton Hills Pump Station • Cherry Valley Pump Station • Perris Lake and Dam West Branch The West Branch continues to head towards its terminus at Pyramid Lake and Castaic Lake in the Angeles National Forest to supply the western Los Angeles basin. It passes through parts of Kern and Los Angeles counties. West Branch facilities include • Oso Pumping Plant • Peace Valley Pipeline • Warne Powerplant • Angeles Tunnel • Castaic Power Plant Bikeway When it was open, the California Aqueduct Bikeway was the longest of the paved paths in the Los Angeles area, at long from Quail Lake near Gorman in the Sierra Pelona Mountains through the desert to Silverwood Lake in the San Bernardino Mountains. This path was closed in 1988 due to bicyclist safety and liability issues. It is expected to remain closed indefinitely due to the continued liability issues and an increased focus on security, especially after the September 11, 2001 attacks. Pumping stations ; Phase I, canal • Las Perillas Pumping Plant , Kings County • Badger Hill Pumping Plant , Kings County ; Phase II, pipeline and tunnel • Devil's Den Pumping Plant , Kern County • Bluestone Pumping Plant , Kern County • Polonio Pass Pumping Plant , San Luis Obispo County ==Hydrography==

Two major river systems drain and define the two parts of the Central Valley. Their impact on the California Aqueduct is both direct and indirect. The Sacramento River, along with its tributaries the Feather River and American River, flows southwards through the Sacramento Valley for about . In the San Joaquin Valley, the San Joaquin River flows roughly northwest for , picking up tributaries such as the Merced River, Tuolumne River, Stanislaus River and Mokelumne River. == Land subsidence ==

Background Land subsidence is when the land gradually or suddenly sinks or settles due to movement or removal of natural materials such as water, minerals, oil and natural gases. More often than not, subsidence occurs when large quantities of groundwater are removed from sediment or rocks. As groundwater is drawn from deep underground layers of clay, the clay compresses, causing subsidence. In cases of groundwater removal, disruption to land on the surface and underground water storage can either be elastic, meaning recoverable, or inelastic, meaning permanent. Coarse-grained sediment which holds groundwater can be drained and recharged with minimal underground and surface level damage and the change that does occur is considered seasonal subsidence. The aqueduct has been increasing in subsidence rates rapidly, even though it was relatively stable for many years after being constructed. The Tulare Basin is subsiding at a rate of about 30 cm (one foot) per year, as measured by NASA's GRACE satellite. The Central Valley, where a large portion of the California Aqueduct runs through, has been affected by the pumping of groundwater and subsequent land subsidence. Farmers in and near the Central Valley have become reliant on groundwater especially with recent droughts impacting the amount of readily accessible surface water. From October 2011 to September 2015 measurements made on groundwater levels in the San Joaquin Valley's aquifers recorded a loss of 14 km3/year, a total of 56 km3. Consequences Subsidence can put land, both private and public, at risk of infrastructure damage. Bridges, levees, roads, and groundwater wells are either at risk of damage or have been damaged already. With subsidence progression, underground aquifers could be at risk and water storage from them could be threatened. Damage and sinking of the canal of the aqueduct has already occurred from subsidence which has made the canal less reliable. Capacity has been compromised due to damage to the canals and therefore has caused problems and delays with delivering the water across the state, as well as higher rates and costs for power and operation. == In popular culture ==

A documentary about the decline of the United States' infrastructure, The Crumbling of America, was commissioned by the U.S. A&E network in the late 2000s. The documentary is typically shown on the History television channel in the United States, although other educational broadcasters globally have shown it. It features the Clifton Court Forebay (a primary intake point for California Aqueduct) as a "strategic piece of California freshwater infrastructure" subject to shutdown for up to two years if struck by an earthquake of magnitude 7.5 or greater. The aqueduct is featured in an episode of ''California's Gold'' with Huell Howser. ==See also==