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88-568: The park features an $ 11 million, 5,000-square-foot Delta Visitor Center , which operates as a natural history museum, science laboratory, and staging area for paddling and hiking trips along the Sacramento–San Joaquin River Delta . The new visitor center opened in October 2012. The center includes a 1,200 square feet (110 m) interactive map of the Sacramento–San Joaquin River Delta that shows visitors how water flows through

176-580: 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

264-470: 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

352-479: 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

440-463: 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

528-422: 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,

616-720: A predominantly Mediterranean climate , and are primarily within the California chaparral and woodlands ecoregion . However, the moister areas of the Santa Cruz Mountains lie within the Northern California coastal forests ecoregion, characterized by forests of Coast redwood . Isolated groves of Coast redwoods are also found in the Big Sur region of the Santa Lucia Range, making them the southernmost natural occurrences of

704-401: 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

792-502: 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

880-862: 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,

968-421: 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

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1056-737: A transform fault system. During 1877, these deposits hit their peak production of mercury, producing approximately 2,776 metric tons (3,060 short tons). These abandoned mines are still a source of mine waste runoff in Cache Creek and other downstream bodies of water. The Northern Coast Ranges are a section of the California Coast Ranges. They run parallel to the Pacific Coast from the North San Francisco Bay Area to coastal Del Norte County . The Klamath Mountains , including

1144-435: 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

1232-536: 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

1320-549: 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 the sediment to pile up, forming expansive islands. Geologically, the Delta has existed for about 10,000 years, since

1408-470: 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

1496-565: 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

1584-582: 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

1672-422: 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

1760-559: Is open daily from sunrise to sunset. The Visitor Center is open Wednesday-Sunday, 10am to 4pm. The park is at 69 Big Break Road in Oakley. It can be reached by private vehicles from Main Street, and there is no fee for parking or admission. Tri Delta Transit #300 provides access to the park through Vintage Parkway and Big Break Road on weekdays. The park is generally wheelchair accessible. Dogs are permitted, except in marsh and wetland habitats in

1848-568: 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

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1936-691: 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

2024-400: 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

2112-471: The California chaparral and woodlands ecoregion, home to a number of plant communities including: mixed evergreen forest ; oak woodland ; and Interior chaparral and woodland . A major specific plant community of the inner ranges is Mediterranean California Lower Montane Black Oak-Conifer Forest , which supports particularly high biodiversity within the California Coast Ranges, including the nominate California Black Oak . Columbian Black-tailed Deer are

2200-909: The East San Francisco Bay Area , and run south into Santa Barbara County . The Transverse Ranges lie to the south. The San Joaquin Valley is on the east, and Pacific Ocean on the west. The Southern Coast Ranges include the Berkeley Hills , the Diablo Range , the Santa Cruz Mountains , the Gabilan Range , the Santa Lucia Range and Sierra de Salinas , the Temblor Range , and the Sierra Madre . There are Outer Southern Coast Ranges along

2288-676: The King Range , which meet the sea in the " Lost Coast " region. The southernmost peak of the Northern Coast Ranges is Mount Tamalpais . The highest point in the Northern Coast Ranges is Mount Linn , at 8,098 ft. (2,468 m). The Northern Coast Ranges consist of two main parallel belts of mountains, the Outer Northern Coast Ranges lying along the coast, and the Inner Northern Coast Ranges running inland to

2376-603: 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 the Delta, including both land and water, is about 1,100 square miles (2,800 km ). Its population

2464-512: 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

2552-674: The Siskiyou Mountains sub-range, lie to the north and northeast. The Southern Coast Ranges lie to the south. The Northern Coast Ranges run north–south parallel to the coast. Component ranges within the Northern Coast Ranges include the Mendocino Range of western Mendocino County and the Mayacamas , Sonoma , and Vaca Mountains and the Marin Hills of the North Bay . They also include

2640-573: The Spanish word chaparro , applied to California scrub oaks and Coastal scrub oaks . Common tree species of oak woodlands include oaks, California bay , and buckeye . Riparian species of the coast ranges include sycamore , white alder , willows , and bigleaf maple . Columbian Black-tailed deer occupy the northern and more coastal portions of the Southern Coast Ranges, and California mule deer occupy inland and southernmost portions of

2728-663: The Transverse Ranges , Peninsular Ranges and the Klamath Mountains . Physiographically , they are a section of the larger Pacific Border province , which in turn is part of the larger Pacific Mountain System physiographic division. UNESCO has included the " California Coast Ranges Biosphere Reserve " in its Man and the Biosphere Programme of World Network of Biosphere Reserves since 1983. The northern end of

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2816-586: 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

2904-668: 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

2992-568: The California Coast Ranges overlap the southern end of the Klamath Mountains for approximately 80 miles (130 km) on the west. They extend southward for more than 60 miles (97 km) to where the coastline turns eastward along the Santa Barbara Channel , around the area of Point Conception . Here the southern end meets the Los Angeles Transverse Ranges , or Sierras de los Angeles . The rocks themselves that comprise

3080-481: 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

3168-449: 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

3256-401: 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

3344-532: 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

3432-498: The Delta in its current condition and configuration. The second would restore parts of the Delta more closely to its natural state but include the construction of an additional Peripheral Canal to maintain the water supply currently provided by the Delta. California Coast Ranges The Coast Ranges of California span 400 miles (644 km) from Del Norte or Humboldt County, California , south to Santa Barbara County . The other three coastal California mountain ranges are

3520-514: 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

3608-513: 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

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3696-478: 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

3784-419: 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

3872-570: 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

3960-588: 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

4048-595: The Pacific Ocean on the west, and Inner Southern Coast Ranges to the east, inland to the San Joaquin Valley . The central and southern San Francisco Bay and the Salinas Valley lie between them. The highest point of the Southern Coast Ranges is Junipero Serra Peak in the Santa Lucia Range, at 5,862 feet (1,787 m). Other peaks include Mount Diablo at 3,849 feet (1,173 m), and Mount Hamilton at 4,196 feet (1,279 m). The Southern Coast Ranges have

4136-510: 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

4224-537: 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

4312-467: 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

4400-614: 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

4488-449: 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 ,

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4576-599: 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

4664-504: 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

4752-494: 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

4840-465: 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

4928-630: The east. They are separated by a long system of valleys. The northern valley portion is drained by the Eel River and its tributaries, and the southern by the Russian River . A series of short rivers, including the Mattole , Gualala , and Navarro rivers, drain the western slopes of the ranges. The eastern slopes of the ranges drain into the Sacramento Valley . Clear Lake lies in the southeast portion of

5016-454: 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

5104-427: 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

5192-574: 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 the Central Delta islands; much of the Delta region today sits below sea level, behind levees earning it

5280-563: The endemic Santa Lucia Fir , the rarest species of fir on earth. The California chaparral and woodlands ecoregion has a great range of plant communities in the Southern Coast Ranges, including mixed evergreen forests , oak woodland and savannas , grasslands , northern coastal scrub , and the Monterey Pine woodlands of the Monterey Peninsula and two other coastal enclaves of the Santa Lucia Range. The name " chaparral " comes from

5368-542: 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

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5456-436: 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

5544-410: 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

5632-439: 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,

5720-403: 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

5808-541: 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

5896-402: 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

5984-502: 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

6072-417: 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

6160-404: 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

6248-416: The most widespread large mammal, after humans, of the Northern Coast Ranges. The rivers in the ranges are home to several species of salmon . The Southern Coast Ranges , of the California Coast Ranges in the Pacific Coast Ranges System, run north and south, parallel to the Pacific Coast in north-central through north-southern California. The Southern Coast Ranges begin on the San Francisco Peninsula and in

6336-455: The mountains are of a great variety and widely varying geologic ages. Most of the rocks were formed during the Tertiary , Cretaceous and Jurassic periods. Most were deposited on the sea bottom as sediments, but in many places also had cracks, crevices and other gaps infused with molten lava or other masses of igneous rock , which were forced in molten condition into the sedimentary rocks. All of

6424-484: 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

6512-425: 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

6600-583: The park. Sacramento%E2%80%93San Joaquin 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 the rivers enter Suisun Bay , which flows into San Francisco Bay , then

6688-431: 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

6776-614: 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

6864-483: The range has been folded and faulted during several periods, with erosion of the softer rock giving much of the current appearance. The California Ranges had a high production of mercury following the discovery of gold in the Sierra Nevada . In the Cache Creek Basin , Cenozoic cinnabar deposits near Clear Lake are the northernmost of a group of similar deposits associated with volcanism and migration of

6952-464: The range, and drains eastward via Cache Creek . U.S. Route 101 runs generally north–south in the valleys between the Outer and Inner Northern Coast Ranges. The seaward face of the coastal Outer Northern Coast Ranges is part of the Northern California coastal forests ecoregion, home to lush forests of Coast Redwood and Coast Douglas-fir . The inland and dryer Inner Northern Coast Ranges are part of

7040-453: 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

7128-706: The region. A 30-by-50 model of the delta is also located at the park, as well as restored wetlands. The park is named for a break in the levee system that flooded an asparagus farm between the San Joaquin River and Dutch Slough in 1928. The break formed a small bay along the river, near the area where fresh water from the river mixes with salt water from San Francisco Bay . According to the East Bay Regional Parks District, Big Break Regional Shoreline provides habitat for at least 70 species of birds and several species of mammals. They include: The park

7216-513: 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

7304-660: 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

7392-600: The species. Some of the rarest forest habitat that occurs in the California Coast Ranges are the Maritime Coast Range Ponderosa Pine forests of the western Santa Cruz Mountains. These isolated groves may include Ponderosa pine , Douglas fir , and knobcone pine . Notably, the highest slopes of the Santa Lucias contain small patches of Sierran Conifer forest, including incense cedar , and ponderosa, Jeffrey, and sugar pines . Steep rocky slopes harbor

7480-490: 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

7568-409: 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

7656-412: 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

7744-467: 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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