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103-791: The plant is the second pumping plant for the California Aqueduct and the South Bay Aqueduct . It provides the necessary fluid head (potential energy) for the California Aqueduct to flow for approximately 95 miles (153 km) to where the Coastal Branch splits from the "main line" approximately 10 miles (16 km) south-southeast of Kettleman City . After the Coastal Branch junction, the line continues south by gravity another 66 miles (106 km) to

206-526: A concrete -lined channel 40 feet (12 m) at the base and an average water depth of about 30 ft (9.1 m). The widest section of the aqueduct is 110 feet (34 m) and the deepest is 32 feet (9.8 m). Channel capacity is 13,100 cubic feet per second (370 m /s) and the largest pumping plant capacity at Dos Amigos is 15,450 cubic feet per second (437 m /s). A 2021 study published in Nature Sustainability estimated that

309-591: A 62 percent chance of occurring in the next two decades if subsidence isn’t addressed." Simultaneous levee failures on the Delta's 57 islands in the wake of an earthquake which allow the inflow of brackish San Francisco Bay waters could threaten the water supply for the Central Valley , which includes both the irrigation water for its $ 17 billion agricultural economy and the drinking water for about 25 million people. About 500 plant and animal species inhabit

412-470: A challenge to the agricultural community to eliminate. The plants spread by budding and spreading its seeds, and those seeds fall to the bottom of the water, where they can stay viable in the muck for years. The Hyacinth can form a mat up to 6 feet (1.8 m) thick, shutting off light and becoming acidic when they decompose. The Delta was formerly populated by large herds of deer and tule elk ; their trails were so vast that early Spanish explorers supposed

515-485: A chance to learn about the disaster that represented the largest domestic loss of life in the U.S. in World War II, and the impact it had on race relations in the U.S. military. Brannan Island State Recreation Area offers boat launches and facilities that support fishing, windsurfing, waterskiing, and sailing, in addition to campsites, picnic areas and trails to allow visitors to explore the marshes and islands of

618-400: A halt on significant compaction and a recovery in ground water levels now with less ground water pumping. 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 one foot per year, as measured by NASA's GRACE satellite. The Central Valley, where a large portion of

721-471: A marshy interior "bowl" that flooded intermittently with the seasons and tides. The height of these natural levees, formed from overbank deposits of sediments deposited by annual river floods, ranged from one foot (0.30 m) above mean high tide at Sherman Island on the Sacramento River, to seven to eight feet (2.1 to 2.4 m) at Andrus , Staten and Tyler Islands, located further east near

824-422: A north–south route for migratory birds, crosses the Delta. The migratory birds provide both birdwatching and hunting opportunities. Including the northern Suisun Marsh , there are over 150 private duck clubs in the area. The levee system allowed farmers to drain and reclaim almost 500,000 acres (780 sq mi; 2,000 km ) of the Delta, then a tidal marsh. Once the rivers were confined to their riverbeds,

927-401: A result the Delta is most susceptible to salinity intrusion between February and June. However, regulation provided by dams helps boost freshwater flows during dry summers and autumns, reducing the risk of salinity intrusion in these months. Diversions located at the southern end of the Delta, however, have negated some of the benefits of upstream dams. The powerful pumps that supply water for

1030-510: A risk for human consumption as well. After numerous rounds of mitigation following the 2005 Smelt Biological Opinion (BiOp) lead to pumping restrictions from the State and Federal projects from the Delta, a number of potential solutions to the Delta's problems have been proposed. These followed the CALFED process which had offered several staged solutions. A first set of alternatives would maintain

1133-894: A river valley through which the continuation of the Sacramento and San Joaquin Rivers flowed to the Pacific Ocean. When sea levels rose again, ocean water backed up through the Carquinez Strait into the Central Valley; the combination of the narrow strait and tidal action pushing inland dramatically slowed the current of these rivers and forced them to drop sediment. The early delta was composed of shifting channels, sand dunes, alluvial fans and floodplains that underwent constant fluctuation because of rapidly rising seas – one inch (25 mm) per year. About 8,000 years ago,

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1236-674: A steel truss design in Gujarat and a suspension cable design in Punjab . 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 . The Coastal Branch splits from

1339-421: A threat that has the potential to impact human life. Several types of toxic cyanobacteria have appeared in the Delta, with Microcystis aeruginosa being one of the most common types. Microcystis aeruginosa produce microcystins which are hepatotoxins that can cause liver cancer. Frequent Microcystis blooms have impacted the food web of the Delta at multiple trophic levels . Microcystis spp. blooms in

1442-508: Is a stub . You can help Misplaced Pages by expanding it . California Aqueduct The Governor Edmund G. Brown California Aqueduct is a system of canals, tunnels, and pipelines that conveys water collected from the Sierra Nevada Mountains and valleys of Northern and Central California to Southern California . Named after California Governor Edmund Gerald "Pat" Brown Sr. , the over 400-mile (640 km) aqueduct

1545-435: Is also provided for wildlife refuges and habitat conservation works. The Contra Costa Canal and North Bay Aqueduct also take Delta water, supplying the nearby San Francisco Bay Area. Locally, the Delta provides water for cities and towns in five counties and for over 1,800 agricultural users. The Delta is also a popular site for recreation and is used for sailing, waterskiing, houseboating, fishing, and hunting. The Delta

1648-548: Is also transected by the Middle River and Old River, former channels of the San Joaquin. These rivers transport more than 30 million acre-feet (8.9 cu mi; 37 km ) of water through the Delta each year – about 50 percent of all California's runoff. Nearby cities include Lodi and Stockton to the east, Tracy and Manteca to the south, Brentwood to the southwest, and Pittsburg and Antioch to

1751-427: Is being used to recreate maps to closely watch the progression of the land around the aqueduct. 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

1854-751: 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 447 miles (719 km). In the San Joaquin Valley, the San Joaquin River flows roughly northwest for 365 miles (587 km), picking up tributaries such as the Merced River , Tuolumne River , Stanislaus River and Mokelumne River . In

1957-475: Is essential to provoke the slowing of river current and the resulting sediment deposits that now make up the Delta. The Delta in its contemporary (pre-1850s) state began to form about 10,000 years ago at the end of the last Ice Age. During the Ice Age global sea levels were about 300 ft (91 m) lower than today, and the Delta region, as well as Suisun Bay, the Carquinez Strait and San Francisco Bay, were

2060-606: Is featured in an episode of California's Gold with Huell Howser . San Joaquin-Sacramento River Delta The Sacramento–San Joaquin River Delta , or California Delta , is an expansive inland river delta and estuary in Northern California . The delta is formed at the western edge of the Central Valley by the confluence of the Sacramento and San Joaquin rivers and lies just east of where

2163-579: Is home to over 100 marinas and 25 yacht clubs. In 2010, over seven million 'annual visitor boating days' occurred on the Delta, according to a local government survey. The Delta is home to several state and regional parks, reflecting a variety of recreational activities. These include historical interpretative centers, including Delta Meadows and Locke Boarding House and the Old Sacramento State Historic Park . The Port Chicago Naval Magazine National Memorial offers visitors

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2266-599: Is not considered a true river delta, but rather an inverted river delta , as it formed inward (sediments accumulating progressively inland) rather than outward. The only other major river delta in the world located this far inland is the Pearl River Delta in China. The main source rivers include the Sacramento River from the north, the San Joaquin from the southeast, and the Calaveras and Mokelumne Rivers from

2369-422: Is now relatively robust but should be improved to effectively eliminate the risk of failure in extreme floods and earthquakes. It emphasizes the significant value of the infrastructure that passes through the Delta, including water conveyance, in addition to life and property, and the value of the Delta as a Place. A 2019 article states that "a catastrophic levee failure, defined as 20 islands flooding at once, has

2472-490: Is owned and operated by the Los Angeles Department of Water and Power , is located on the northern end of Castaic Lake , while Castaic Dam is located at the southern end. Land subsidence has occurred along the aqueduct and has had a steady increase since its relatively stable state post construction of the aqueduct. The aqueduct serves 35 million people and 5.7 million acres of farmland, and begins at

2575-640: Is required again. Delta waterways are also major transportation corridors for agricultural products; the ports of Sacramento and Stockton , located on the Sacramento and San Joaquin rivers, respectively, are the most important inland ports in California. The San Joaquin River throughout most of the Delta and the lower Sacramento River below its connection to the Sacramento Deep Water Ship Channel are routinely dredged to allow

2678-660: Is shipped to both the Benicia Refinery and the Martinez Refinery by water. Nearby is the Port Chicago Marine Ocean Terminal , a facility that supports the U.S. Navy. The Delta is often considered the nexus of California's statewide water system . About half the total river flow in the state passes through this region, from which water is exported to other areas of the San Joaquin Valley, Southern California and portions of

2781-846: Is the principal feature of the California State Water Project . The aqueduct begins at the Clifton Court Forebay at the southwestern corner of the Sacramento–San Joaquin River Delta . The aqueduct then heads south, eventually splitting into three branches: the Coastal Branch, ending at Lake Cachuma in Santa Barbara County ; the West Branch, conveying water to Castaic Lake in Los Angeles County ; and

2884-400: Is used as a sedimentation enhancing strategy to reduce subsidence and restore the wetlands in the Delta. Land subsidence has endangered the Delta's system of protective levees, occasionally triggering levee failure and subsequent flooding. Using the Delta as the primary valve in a linear water system may have been convenient for a period, but that convenience has come at a high price for

2987-635: Is usually dry nowadays because the rivers feeding it have been diverted for agricultural purposes. The rivers of the Central Valley converge in the Sacramento-San Joaquin Delta , a complex network of marshy channels, distributaries and sloughs that wind around islands mainly used for agriculture. Here the freshwater of the rivers merges with tidewater, and eventually reach the Pacific Ocean after passing through Suisun Bay , San Pablo Bay , upper San Francisco Bay and finally

3090-705: 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 When it was open, the California Aqueduct Bikeway was the longest of the paved paths in the Los Angeles area , at 107 miles (172 km) long from Quail Lake near Gorman in the Sierra Pelona Mountains through the desert to Silverwood Lake in

3193-522: The Buena Vista Pumping Plant . The California Aqueduct is made up of small bodies of water such as canals and tunnels that are able to transport water. The aqueduct starts at the Clifton Court Forebay in Sacramento and makes its way down South where it splits into three different branches that is broken up into different areas of the counties down South. These categories include West Branch, East Branch, and Coastal Branch. As

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3296-543: The Golden Gate . Many of the islands now lie below sea level because of intensive agriculture, and have a high risk of flooding, which would cause salt water to rush back into the delta, especially when there is too little fresh water flowing in from the Valley. The Sacramento River carries far more water than the San Joaquin, with an estimated 22 million acre-feet (27 km ) of virgin annual runoff, as compared to

3399-486: The Los Angeles Basin . At Edmonston Pumping Plant it is pumped 1,926 ft (587 m) 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

3502-524: The Port of Stockton to the San Joaquin's confluence with the Sacramento near Antioch. "The virgin California Delta was so vast, wild and confusing – its sloughs meandered everywhere and led nowhere – that John C. Frémont lost a whole regiment in there for several days, and some who ventured in just disappeared." Marc Reisner , A Dangerous Place (2003) The Delta was formerly located at

3605-531: 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 . Two major river systems drain and define the two parts of the Central Valley . Their impact on the California Aqueduct

3708-850: 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 60 mi (97 km) to the O'Neill Forebay at

3811-585: The San Luis Reservoir . From the O'Neill Forebay, it flows approximately 16 mi (26 km) to the Dos Amigos Pumping Plant . After Dos Amigos, the aqueduct flows about 95 mi (153 km) to where the Coastal Branch splits from the "main line". The split is approximately 16 mi (26 km) south-southeast of Kettleman City . After the coastal branch, the line continues by gravity another 66 mi (106 km) to

3914-598: The Arkansas or Swampland Act , which allowed for the transfer of title for wetlands to private owners on the conditions that the land would be reclaimed. In California, more than two million acres (3,100 sq mi; 8,100 km ) of wetlands were partitioned under the Swampland Act, of which 500,000 acres (780 sq mi; 2,000 km ) were in the Sacramento–San Joaquin Delta, roughly

4017-681: The Bay area to supply some 1,130,000 acres (1,770 sq mi; 4,600 km ) of farmland and 23 million people in central and Southern California. The Delta provides an estimated seven million acre-feet (2.1 cu mi; 8.6 km ) of water per year, of which about 100,000 acre-feet (0.030 cu mi; 0.12 km ) are exported to the San Francisco Bay Area, 1.7 million acre-feet (0.50 cu mi; 2.1 km ) are used locally, and over five million acre-feet (1.5 cu mi; 6.2 km ) are exported to

4120-703: The Buena Vista Pumping Plant. From the Buena Vista, it flows approximately 27 mi (43 km) to the Teerink Pumping Plant. After Teerink it flows about 2.5 mi (4.0 km) to the Chrisman Pumping Plant. Chrisman is the last pumping plant before Edmonston Pumping Plant , which is 13 mi (21 km) from Chrisman. South of the plant the west branch splits off in a southwesterly direction to serve

4223-456: 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. However, overuse of groundwater can cause irreversible damage. During the 2011-2017 California drought , a record high drought, groundwater and its storage capabilities in

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4326-856: The California Aqueduct, was completed in 1968. With construction beginning in 1994, Phase II consists of 101 mi (163 km) of a 42–57-inch (1.07–1.45 m) 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 42 mi (68 km) from Vandenberg through Vandenberg Village , Lompoc , Buellton , and Solvang where it terminates at Lake Cachuma in Los Padres National Forest . Coastal Branch facilities include: The aqueduct splits off into

4429-661: The Central Delta islands; much of the Delta region today sits below sea level, behind levees earning it the nickname "California's Holland ". Much of the water supply for Central California and Southern California is also derived from the Delta, via pumps located at the southern end of the Delta. The pumps deliver water for irrigation in the San Joaquin Valley and municipal water supply for Southern California. The Delta consists of approximately 57 reclaimed islands and tracts but there are nearly 200 islands in

4532-491: The Central Valley Project and State Water Project cause water in the Delta to flow from north to south instead of the natural direction of east to west. This has caused multiple environmental issues, such as the disruption of fish migration and salinity buildup in the eastern Delta, where salts can no longer be flushed to the sea by natural river flows. Since 1900, there have been over 160 levee failures in

4635-449: The Delta can be attributed to a variety of factors with the most important being lowered streamflow . From 2004 through 2008 researchers collected different water quality parameters during the cyanobacteria blooms and determined that the blooms appeared after reaching a threshold of 19 °C (66 °F) which was exacerbated by reduced precipitation , reduced streamflow, and increased nutrient concentrations. They also determined that

4738-401: The Delta cannot be irrigated using conventional methods due to the highly absorbent quality of the peat soil and irregularities caused by land subsidence. Irrigation is typically carried out periodically by piping water into small "spud ditches", which spread water over large areas and raise the local water table . The heightened groundwater is then gradually depleted by the crop until irrigation

4841-545: The Delta from the summit of nearby Mount Diablo . For decades, the Delta was little utilized by the Spanish colonists. Expeditions from 1806 to 1812 failed to locate suitable mission sites in the Delta area. However, frequent military expeditions were made into the Delta from 1813 to 1845 in response to animosities between the Native Americans and the Spanish and later Mexicans; also several land grants were made in

4944-514: The Delta was 515,264 as of 2000. Altogether, the Delta covers 1,153 square miles (2,990 km ), with 841 sq mi (2,180 km ), or nearly 73 percent, devoted to agriculture. About 100 sq mi (260 km ) of the Delta area is urban and 117 sq mi (300 km ) are undeveloped land. The rivers, streams, sloughs and waterways of the Delta total about 95 sq mi (250 km ) of surface, although this fluctuates greatly with seasons and tides. Geologically, it

5047-513: The Delta were found to decrease the diversity of the aquatic microbial community. Additionally, the cyanobacteria blooms in the Delta have led to decreased zooplankton mass and density . There is also concern for further spread throughout the food web via bioaccumulation . Microcystins were detected in the tissue of clams at levels much higher than the ambient water around them because of microcystin's ability to covalently bind to tissue. The increased occurrences of cyanobacteria blooms in

5150-478: The Delta's ecosystem. Delta fish populations have been significantly reduced due to the reclamation of marshland and diversions of fresh water. In 2004, the Delta smelt was found to be on the edge of extinction. The survival of the Delta smelt has been one of the largest environmental issues in California, as environmental measures enacted to protect its population have often reduced the amount of water available for federal water projects that depend on water pumped from

5253-494: The Delta, including both land and water, is about 1,100 square miles (2,800 km ). Its population is around 500,000. The Delta was formed by rising sea level following glaciation, leading to the accumulation of Sacramento and San Joaquin River sediments behind the Carquinez Strait , the sole outlet from the Central Valley to San Pablo Bay. The narrowness of the Carquinez Strait coupled with tidal action has caused

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5356-419: The Delta, which is one of the largest estuaries in western North America. Before agricultural development of the Delta region, the Delta's many islands were forested by Tule , bulrush , and various reeds that flourished in intermittently flooded, low-lying marshy areas. Over thousands of years, the growth and decay of the various swampland plants formed a layer of peat 50 feet (15 m) deep in places, hence

5459-582: The Delta. A 2010 study shows that the anglers in the Delta who ate these fish had higher levels of mercury in their system. Delta fish have also been found to have high levels of a toxin called methylmercury which originates from old gold rush era mines in the Sierras. In that same study, it was found that women along the delta were consuming high numbers of fish, making them more susceptible to poisoning. Nutria were found in Merced County in 2017 on

5562-630: 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: The West Branch continues to head towards its terminus at Pyramid Lake and Castaic Lake in

5665-569: The East Branch, connecting Silverwood Lake in San Bernardino County . The Department of Water Resources (DWR) operates and maintains the California Aqueduct, including one pumped-storage hydroelectric plant, Gianelli Power Plant . Gianelli is located at the base of San Luis Dam , which forms San Luis Reservoir , the largest offstream reservoir in the United States. The Castaic Power Plant, while similar and which

5768-595: The Mokelumne River. An estimated 60 percent of the Delta flooded for up to two hours each day at high tide; during spring tides or river floods, it was not uncommon for the entire Delta to be under water. Humans have inhabited the Delta for up to 4,300 years. The estimated indigenous population of the Delta at the time of first contact with Europeans was about 3,000–15,000, predominantly Miwok and Maidu , with some estimates ranging up to 20,000. The Native Americans lived in villages of 200–1,000 people on

5871-520: The Sacramento–San Joaquin Delta. The California Office of Environmental Health Hazard Assessment has issued a safe eating advisory for any fish caught in Central and South parts of the Delta due to elevated levels of mercury and PCBs. In addition, there is a notice of "DO NOT EAT" for any fish or shellfish from the Port of Stockton . There is a separate safe eating advisory for the Northern part of

5974-541: The Sacramento–San Joaquin River Delta. These numbers include multiple failures of a single levee structure. Levee failures, also known as breaches, can be caused by overtopping or structural failure . One of the most recent examples of levee failure in the Sacramento–San Joaquin River Delta occurred in June 2004 when a levee breach caused more than 150,000 acre-feet (190,000,000 m ) of water to flood

6077-403: The San Joaquin Valley saw a sharp decline. From October 2011 to September 2015 measurements made on groundwater levels in the San Joaquin Valley's aquifers recorded a loss of 14 km /year, a total of 56 km . During this same period up to 1,000 mm of land subsidence was measured in the San Joaquin Valley. Concerns around groundwater depletion have contributed to legislation to reduce

6180-467: The San Joaquin Valley, coastal Central and Southern California. Intrusion of brackish water into the Delta is a recurring natural phenomenon; however, it became a serious issue after the development of agriculture in the upper Sacramento and San Joaquin valley reduced inflows. Multiple droughts between 1910 and 1940 caused significant salinity intrusion in the Delta because of the reduction of freshwater inflows. The growing Delta water quality issue provided

6283-399: The San Joaquin's approximately 6 million acre-feet (7.4 km ). Intensive agricultural and municipal water consumption has reduced the present rate of outflow to about 17 million acre-feet (21 km ) for the Sacramento and 3 million acre-feet (3.7 km ) for the San Joaquin; however, these figures still vary widely from year to year. Over 25 million people, living both in

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6386-571: The aqueduct flows through California it goes through many reservoirs such as San Luis Reservoir . From the San Luis Reservoir to the O'Neill Forebay , the water flows down into the Dos Amigos Pumping Plant which is approximately 16 miles. After going through Dos Amigos Pumping Plant It reaches the Coastal Branch that is split for across a line that goes for about 16 miles towards Kettleman City . 36°55′26″N 120°49′40″W  /  36.923889°N 120.827778°W  / 36.923889; -120.827778 This water supply –related article

6489-614: The area was inhabited by cattle. Significant numbers of California grizzly bears could also be found in the Delta. The extensive wetlands of the Delta supported massive bird populations, half the migrating waterfowl in California continue to pass through the Delta. A survey in 2012 recorded a spring duck population of 48.6 million, the highest since counts began in 1955. Large mammals in the Delta have not fared so well; with most of their habitat converted to agriculture, remaining populations were highly susceptible to human impacts and natural disasters. Grizzlies were hunted to extinction, while

6592-449: The area. Originally a Delta farming island, Franks Tract flooded in 1936 and again in 1938. The levees were never repaired and the island remained submerged, becoming an expanse of open water dotted with remnants of the original levees now the only landforms. In 1959, the area became a state park. Franks Tract State Recreation Area is accessible only by water and is used for fishing, waterfowl hunting, and boating. The Pacific Flyway ,

6695-429: The bottom of a large inland sea in the Central Valley, which formed as the uplift of the California Coast Ranges blocked off drainage from the Sierra Nevada to the Pacific. About 560,000 years ago, water breached the mountains, carving out the present-day Carquinez Strait and San Francisco Bay . The drainage of all the water through this narrow gap formed a bottleneck in the Central Valley's outflow; this constriction

6798-409: 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. A documentary about the decline of the United States' infrastructure, The Crumbling of America ,

6901-541: 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. However, fine-grained sediment takes longer to draw water out of and recharge and if groundwater levels are left low for too long,

7004-489: The compaction of the sediment is permanent and causes irreversible land subsidence. This often occurs due to human interference, but can also happen from natural phenomena. Subsidence can happen over very large areas or small little sections of land. This has occurred along the California Aqueduct of the State Water Project since construction. Human causes include; pumping, mining and fracking. Natural causes include; earthquakes, erosion, glacial movement, soil compaction and

7107-504: The conditions are met Microcystis have the ability to dominate the lower trophic levels hence why they are able to bloom. Additionally, when microcystins are present in the system then the consumers in the food web are at risk due to the effects of bioaccumulation. Fish that are present and active during cyanobacteria blooms can often have microcystin levels high enough to produce sublethal effects. Because microcystins can concentrate inside fish at multiple trophic levels it also represents

7210-440: The delta that are named or not named. These are all surrounded by 1,100 miles (1,800 km) of levees that border 700 miles (1,100 km) of waterways. The southwestern side of the Delta lies at the foothills of the California Coast Ranges , while to the northwest sit the lower Montezuma Hills . Most of the Delta lies within Contra Costa , Sacramento , San Joaquin , Solano and Yolo Counties. The total human population of

7313-576: The demand for groundwater and incentivize farmers to use sustainable irrigation practices. Measurement of this subsidence is done in a few ways. Originally, subsidence was recorded based on land surveying, repeating the surveying, and along with monitoring compaction by recording the data from extensometers at multiple sites. Since then, Global Positioning Systems (GPS) has been used along with land surveying to record subsidence and compaction. More recently, interferometric synthetic aperture radar (InSAR) has been used to monitor subsidence along with GPS. InSAR

7416-541: The east. The Calaveras and Mokelumne are both tributaries of the San Joaquin River. The Sacramento and San Joaquin Rivers join at the western end of the Delta near Pittsburg , at the head of Suisun Bay, although they are linked upstream by the Georgiana Slough , which was first used by steamboats in the 19th century as a shortcut between Sacramento and Stockton . The southwestern part of the Delta

7519-454: The eastern edge of the Delta, where the land was higher and less susceptible to flooding. Their lives centered around the abundant reeds or tules that grew on the Delta islands, which they used to make houses, boats, and garments. Staple foods included tule roots and pollen, acorns, wild fruits and seeds, fish and game. Europeans first entered the Delta region in 1772, when Spanish explorer Don Pedro Fages and missionary Juan Crespí observed

7622-427: The edge of the Delta. State officials are concerned that they will harm the infrastructure that sends water to San Joaquin Valley farms and urban areas. The Delta has seen numerous cyanobacteria blooms with increasing frequency over the past two decades. Cyanobacteria have the potential to produce cyanotoxins which can pose a risk to humans and animals upon contact. Because of this cyanobacteria blooms are seen as

7725-565: The entire island of Jones Tract . But, the significant improvements made to the Delta levee system since 1982 have reduced the incidence of failures to this one major failure in 30 years. The most up-to-date description and discussion of the Delta levee system can be found in the Economic Sustainability Plan of the Delta Protection Commission. This study concluded that the Delta levee system

7828-436: The entirety of Sherman Island, some 14,000 acres (22 sq mi; 57 km ), was diked and drained by a system of levees, flumes and floodgates. By the 1890s, the original levee system had been largely replaced with stronger embankments consisting of clay dredged from nearby river bottoms. By 1900, about 235,000 acres (367 sq mi; 950 km ), or nearly half of the Delta's land area, had been reclaimed. Most of

7931-410: The environment. —Paul Shigley, The Devil Is in the Delta (2012) Land subsidence also allows brackish water intrusion into the Delta, an issue compounded by the diversion of up to 25% of the freshwater flowing into the Delta. The decreased volume of freshwater in the Delta has had a profound effect on its ecology. In most years, large dams in the Delta watershed fully hold back spring runoff; as

8034-439: The existing Delta infrastructure, forcing landowners to rebuild their levees higher and stronger; more flooding in 1878 and 1881 reinforced these notions. Although land holdings in the Delta were initially limited to 320 acres (0.50 sq mi; 1.3 km ) per buyer, this limit was repealed in 1868, allowing large agricultural conglomerates to take entire islands and carry out massive reclamation projects. From 1868 to 1869,

8137-466: The extremely high fertility of Delta soils. Sediment deposits formed natural levees around the borders of islands, where larger trees, mainly willows, were able to take root and form large riparian forests . The riparian forests were most pronounced along the Sacramento River and the lower Mokelumne River below its confluence with the Cosumnes River . More extensive woodlands were prominent on

8240-541: The farmable land in the Delta had been reclaimed by the 1920s. The Delta produces crops valued at about $ 650 million annually (for the 1998–2004 period), making it one of the most productive farming regions of the United States in terms of crop value per unit area. Agriculture provides secondary benefits of over $ 2 billion to the local economy. Major crops grown in the Delta include corn, grain, hay, sugar beets, alfalfa, tomatoes, asparagus, and safflower; various fruits are also raised here, as well as some livestock. Crops in

8343-402: The flood of 1878 wiped out the last of the elk herds in the Delta. The Delta is home to approximately 22 species of fish, including several Pacific salmon species, striped bass , steelhead trout , American shad and sturgeon . About two-thirds of California's salmon pass through the Delta on their way upstream to spawn. The small Delta smelt is a key indicator species for the health of

8446-466: The formation of sinkholes. Groundwater use and pumping in the area was the major water use for farmers and agriculture in the 1920s, and over time, this over-pumping resulted in land subsidence and a decline in groundwater-level resources. In time, this resulted in major land subsidence by the 1970s with local areas having 1 to 28 feet of subsidence. With the creation and use of the California Aqueduct along these regions, surface water being transported put

8549-502: The fringes of the Delta bordering the riparian zones. Composed primarily of valley oak , box elder and Oregon ash , these oak woodlands grew in bands that stretched up to 3 miles (4.8 km) inland. Farther away from water sources, vegetation gave way to grassland . The water hyacinth has become one of the most destructive plants to the Delta water way. Within one year it will spread and cover as much as 6,500 square feet (600 m ) of water space in one growing season. It has become

8652-487: The initial impetus for building dams on Central Valley rivers to boost dry-season freshwater flows. This eventually became the federal Central Valley Project (CVP), California's first major statewide water system, most of which was built between the 1930s and the 1960s. Today, the California Aqueduct and the Delta-Mendota Canal , two of the state's largest water conveyance facilities, both draw water from

8755-586: The installation of solar panels over the canal could potentially reduce annual water evaporation by 11–22 million US gallons per mile (27,000,000–51,000,000 L/km) 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

8858-404: The lower trophic levels. There have also been large amounts of nutrients monitored in the Delta as a result of various human activities. The increased presence of Microcystis aeruginosa blooms in the Delta represents a continual threat for species at multiple trophic levels. The lower trophic levels are affected from both reduced diversity as well as reduced numbers through competition. When

8961-441: The main line 11.3 mi (18.2 km) 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 116 mi (187 km) and has five pump stations. Phase I, an above-ground aqueduct totaling 15 mi (24 km) from where it branches from

9064-484: The negative attributes associated with climate change like reduced precipitation and increased temperatures could further increase the possibility of cyanobacteria blooms in the Delta. The high prevalence of nutrient concentrations in the Delta also plays a significant part in the increased frequency of Microcystis aeruginosa blooms. Microcystis benefits greatly from anthropogenic inputs of nitrogen which allows it to out-compete other primary producers and dominate

9167-624: 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 240 ft (73 m), while a series of pumps culminating at the Edmonston Pumping Plant raises the water 1,926 ft (587 m) over the Tehachapi Mountains. A typical section has

9270-431: The passage of large cargo ships. The Sacramento River corridor has been maintained to a depth of 7 ft (2.1 m) as early as 1899, and was deepened to 30 ft (9.1 m) in 1955. The Stockton Ship Channel has been dredged since 1913; however, its present depth of 37 ft (11 m) was only achieved in 1987. The Delta is also home to the port of Benicia , an automobile and bulk shipping facility. Petroleum

9373-614: The peat soil of the former tidal marsh was exposed to oxygen. As the oxygen-rich peat soil decomposed and then released carbon dioxide, profound subsidence of the land resulted, of up to 25 feet since the late 1800s. Currently, most of the Delta is below sea level, with a great deal of the western and central Delta at least 15 feet (4.6 m) below sea level. The California Department of Water Resources has experimented with re-flooding areas for wetland restoration , in order to sequester carbon and rebuild soil levels . In addition, shallow flooding of land to restore anaerobic conditions

9476-453: The rate of sea-level rise slackened, allowing wetland plants to take hold in the Delta, trapping sediment; the growth and decay of these plants began to form the vast peat deposits that make up the Delta islands. The Delta reached a stabilized form similar to its mid-1800s state about 2,000–3,000 years ago. Immediately before large-scale human development, most of the Delta islands had saucer-like cross sections, with low natural levees flanking

9579-466: The rivers enter Suisun Bay , which flows into San Francisco Bay , then the Pacific Ocean via San Pablo Bay . The Delta is recognized for protection by the California Bays and Estuaries Policy . Sacramento–San Joaquin Delta was designated a National Heritage Area on March 12, 2019. The city of Stockton is located on the San Joaquin River at the eastern edge of the delta. The total area of

9682-513: The same amount of land that has been developed to date. Agricultural interests in the Delta were protected by the building of levees, a colossal effort first undertaken by Chinese laborers from the 1850s to the 1870s. The Board of Reclamation, formed in 1861, collectivized levee construction in the Delta by grouping islands into areas known as reclamation districts . The early levees were built of peat, and were highly susceptible to wind and water erosion. The Great Flood of 1862 obliterated much of

9785-540: The sediment to pile up, forming expansive islands. Geologically, the Delta has existed for about 10,000 years, since the end of the Last Glacial Period . In its natural state, the Delta was a large freshwater marsh , consisting of many shallow channels and sloughs surrounding low islands of peat and tule . Since the mid-19th century, most of the region has been gradually claimed for agriculture. Wind erosion and oxidation have led to widespread subsidence on

9888-555: The south part of the San Joaquin Valley, the alluvial fan of the Kings River and another one from Coast Ranges streams have created a divide and resultantly the currently dry Tulare basin of the Central Valley, into which flow four major Sierra Nevada rivers, the Kings, Kaweah , Tule and Kern . This basin, usually endorheic , formerly filled during heavy snowmelt and spilled out into the San Joaquin River. Called Tulare Lake , it

9991-550: The southern end of the Delta at the Clifton Court Forebay . Built in the mid-twentieth century, the former supplies water to the Los Angeles Basin and coastal central California via the State Water Project ; the latter, a part of the CVP, provides supplies of irrigation water in the fertile San Joaquin Valley. Although the vast majority of water supplied by these projects is used for agriculture and urban areas, some water

10094-439: The valley and in other regions of the state, rely on the water carried by these rivers. 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,

10197-490: The vicinity of the Delta, including one to John Augustus Sutter , who started the first significant European settlement in the Central Valley just north of the Delta near present-day Sacramento. The Spanish conscripted large numbers of Native Americans for labor on missions; many Native Americans fled deep into the Delta in order to escape their European masters. However, this did not protect them from diseases. A malaria epidemic in 1833 decimated local native populations; this

10300-409: The west. The state capital, Sacramento , is located just to the north of the Delta. The Sacramento River Deep Water Ship Channel connects the Delta to the Port of Sacramento , with its terminus located near Rio Vista , on the northwestern side of the Delta. The Stockton Ship Channel is a dredged and partially straightened section of the San Joaquin River cutting directly through the Delta from

10403-412: Was cheaper and simpler than other fertile regions of California. As a result, the Delta remained California's richest farming region (alongside Los Angeles County ) until the 1940s, when massive federal water projects finally made possible the full-scale irrigation of the main body of the Central Valley. Today, the Delta is still among the state's most productive farming regions. In 1850, Congress passed

10506-539: 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

10609-538: Was probably exacerbated by the marshy geography of the area, which bred large amounts of mosquitoes. The agricultural value of the Delta was first recognized during the California Gold Rush , when farmers planted orchards on Delta islands to provide fresh fruit for mining camps in the Sierra Nevada . Because of the flat terrain coupled with year-round availability of fresh water, irrigation here

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