Sacramento River Delta
Encyclopedia
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
and estuary
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
in northern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. The Delta is formed at the western edge of the Central Valley
California Central Valley
California's Central Valley is a large, flat valley that dominates the central portion of California. It is home to California's most productive agricultural efforts. The valley stretches approximately from northwest to southeast inland and parallel to the Pacific Ocean coast. Its northern half is...
by the confluence of the Sacramento
Sacramento River
The Sacramento River is an important watercourse of Northern and Central California in the United States. The largest river in California, it rises on the eastern slopes of the Klamath Mountains, and after a journey south of over , empties into Suisun Bay, an arm of the San Francisco Bay, and...
and San Joaquin
San Joaquin River
The San Joaquin River is the largest river of Central California in the United States. At over long, the river starts in the high Sierra Nevada, and flows through a rich agricultural region known as the San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean...
rivers and lies just east of where the rivers enter Suisun Bay
Suisun Bay
Suisun Bay is a shallow tidal estuary at in northern California, USA. It lies at the confluence of the Sacramento and San Joaquin Rivers, forming the entrance to the Sacramento-San Joaquin River Delta, an inverted river delta...
(an upper arm of San Francisco Bay
San Francisco Bay
San Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...
). The Delta is recognized for protection by the California Bays and Estuaries Policy
California Bays and Estuaries Policy
The Water Quality Control Policy for the Enclosed Bays and Estuaries of California is published by the California State Water Resources Control Board as guidelines to prevent water quality degradation. The policy is revised as needed.-Geography:...
. The city of Stockton
Stockton, California
Stockton, California, the seat of San Joaquin County, is the fourth-largest city in the Central Valley of the U.S. state of California. With a population of 291,707 at the 2010 census, Stockton ranks as this state's 13th largest city...
is located on the San Joaquin River on the eastern edge of the delta.
Description
Inverted river delta
An inverted river delta is special category of river delta in which the narrow end of the delta emerges on the seafront and the wide end is located further inland, so that with respect to the seafront, the locations of both ends of the delta are inverted....
, one of only a few worldwide. It is the largest estuary on the United States' Pacific Coast
West Coast of the United States
West Coast or Pacific Coast are terms for the westernmost coastal states of the United States. The term most often refers to the states of California, Oregon, and Washington. Although not part of the contiguous United States, Alaska and Hawaii do border the Pacific Ocean but can't be included in...
. The fan-like area of the delta moves downstream, as the two rivers are forced to exit the Central Valley through the Coast Range
Pacific Coast Ranges
The Pacific Coast Ranges and the Pacific Mountain System are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico...
via the narrow channel known as the Carquinez Strait
Carquinez Strait
The Carquinez Strait is a narrow tidal strait in northern California. It is part of the tidal estuary of the Sacramento and the San Joaquin rivers as they drain into the San Francisco Bay...
, which leads to the San Francisco Bay
San Francisco Bay
San Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...
and mainly the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
through the Golden Gate
Golden Gate
The Golden Gate is the North American strait connecting San Francisco Bay to the Pacific Ocean. Since 1937 it has been spanned by the Golden Gate Bridge...
.
The delta consists of myriad small natural and man-made channels (locally called sloughs
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
), creating a system of isolated lowland islands and wetlands defined by dikes or levee
Levee
A levee, levée, dike , embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels...
s. The delta islands are not islands in the classic sense, but are referred to as such because they are completely surrounded by water and are so isolated in many cases that they are accessible only by boat, ferry or aircraft.
An extensive system of earthen levees has allowed widespread farming throughout the delta. Its peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
soil makes it one of the most fertile agricultural
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
areas in California and arguably even the nation, contributing billions of dollars to the state's economy. Certain specialty crops, such as asparagus
Asparagus
Asparagus officinalis is a spring vegetable, a flowering perennialplant species in the genus Asparagus. It was once classified in the lily family, like its Allium cousins, onions and garlic, but the Liliaceae have been split and the onion-like plants are now in the family Amaryllidaceae and...
, are grown in the delta in quantities unmatched anywhere else in the United States.
The delta and its "Thousand Miles of Waterways" are a recreation destination. The warm, breezy summers are popular among water skiers and boaters and even the chilly, foggy
Tule fog
Tule fog is a thick ground fog that settles in the San Joaquin Valley and Sacramento Valley areas of California's Great Central Valley. Tule fog forms during the late fall and winter after the first significant rainfall. The official time frame for tule fog to form is from November 1 to March 31...
winters draw fishermen and hunters.
Development
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
which acts as the funnel for a drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
covering thousands of square miles of California's land. Ultimately flowing into the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, runoff moves through, and into, the delta from several major mountain ranges, including virtually the entire western flank of the Sierra Nevada, the southern reaches of the Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
, and the eastern flanks of those parts of the Pacific Coast Range that border California's Central Valley. For thousands of years, huge swaths of the delta flooded regularly with every spring melt, and the delta represented one of the largest estuaries on North America's west coast.
Starting in the late 19th century, Chinese workers were used to construct hundreds of miles of levee
Levee
A levee, levée, dike , embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels...
s throughout the delta's waterways in an effort to reclaim and preserve farmland and control flooding. These levees confine waterflow to the riverbeds.
Levee failures in the delta can result in the flooding of vast tracts of both agricultural land and developed cities. On 3 June 2004, a 350 foot (110 m) section of a levee 10 mi (16 km) west of Stockton collapsed, flooding the Upper and Lower Jones Tracts
Jones Tract
The Jones Tract is an island containing Lower Jones Tract and the Upper Jones Tract in the Sacramento-San Joaquin River Delta in San Joaquin County, California, fifteen kilometres west of Stockton. The island is bounded on the north by Empire Cut, on the northeast by Whiskey Slough, on the...
, a 12000 acres (4,856.2 ha) island. Tens of thousands of people live near these levees (in many cases, right next to them), in scores of communities ranging from Tracy in the south to Stockton in the east, Sacramento in the north, and the San Francisco Bay area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
in the west. In light of the 2005 Hurricane Katrina
Hurricane Katrina
Hurricane Katrina of the 2005 Atlantic hurricane season was a powerful Atlantic hurricane. It is the costliest natural disaster, as well as one of the five deadliest hurricanes, in the history of the United States. Among recorded Atlantic hurricanes, it was the sixth strongest overall...
disaster affecting similarly low-lying river delta regions in Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
and Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...
, there has been a strong outcry for the state of California and/or the federal government to thoroughly inspect and, if necessary, strengthen and repair the delta's levees.
Construction and history
The total area is around 1100 square miles (2,849 km²), around 70 reclaimed islands and tracts, surrounded by 1100 miles (1,770.3 km) of levees surrounded by 700 miles (1,126.5 km) of waterways. The delta was originally marshland; reclamation was made by the building of levees, by Chinese laborers in the 1850s.A typical levee was constructed as being approximately trapezoidal, 10 ft (3 m) above original ground level, and approximately 30 ft (9.1 m) wide at the base rock armoured on the river side. The construction was a colossal engineering undertaking.
Effects of the Levee System and Freshwater Diversion
The levee system allowed farmers to drain and reclaim almost a 500000 acres (2,023.4 km²) of the Delta, then a tidal marsh. Once the rivers were confined to their riverbeds, 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 subsidenceSubsidence
Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea-level. The opposite of subsidence is uplift, which results in an increase in elevation...
of the land resulted. Now, most the Delta is below sea level, and a great deal of the western and central Delta is at least 15 feet (4.6 m) below sea level. Land subsidence renders unstable the Delta’s 1100 miles (1,770.3 km) system of protective levees, instigating levee failure and subsequent flooding. Land subsidence also allows saltwater intrusion into the Delta, compounded by water diversions that remove 40% of the freshwater flowing into the Delta. Loss of freshwater in the Delta has had a profound effect on the ecology of the Delta.
Ecology
Further, the Delta's fish population is in question. The Delta is home to approximately 22 species of fish including the Delta smeltDelta smelt
Delta smelt, Hypomesus transpacificus, is an endangered slender-bodied smelt, about long, of the Osmeridae family. Endemic to the upper Sacramento-San Joaquin estuary of California, it mainly inhabits the freshwater-saltwater mixing zone of the estuary, except during its spawning season, which...
, a key indicator species for the health of the Delta's ecosystem. In 2004, the Delta smelt was found to be on the edge of extinction.
Current status
The administration of the region is also in flux. CALFED, a federal-state program in charge of the Delta, is on the verge of financial insolvency.A number of solutions have been proposed. A first set of alternatives would maintain the Delta in its current homogeneous freshwater state. The second would return the Delta to a heterogeneous mixed salt water-fresh water body, and would serve in the Delta's current water-supply with a series of aqueducts.
The Contra Costa County Public Works Department is working with the California Coastal Commission and the Department of Boating and Waterways to protect the drinking water quality, prevent pollution and environmental health of the Delta.
A strong movement is emerging to construct a Peripheral Canal
Peripheral Canal
A Peripheral Canal has been proposed to divert water from the Sacramento River, through the San Joaquin-Sacramento River Delta...
to redirect water flowing from the Sacramento and San Joaquin rivers directly to man-made aqueducts headed south and west. Senator Diane Feinstein and Governor Arnold Schwarzenegger
Arnold Schwarzenegger
Arnold Alois Schwarzenegger is an Austrian-American former professional bodybuilder, actor, businessman, investor, and politician. Schwarzenegger served as the 38th Governor of California from 2003 until 2011....
have both declared their support for such a project.
All solutions, however, aim to produce a Delta which simultaneously supports a vibrant ecosystem and continues to supply fresh water to the Central Valley Project
Central Valley Project
The Central Valley Project is a Bureau of Reclamation federal water project in the U.S. state of California. It was devised in 1933 in order to provide irrigation and municipal water to much of California's Central Valley—by regulating and storing water in reservoirs in the water-rich northern...
, the State Water Project and the Bay Area.
In April 2009, the Sacramento River Delta was declared the nation's most endangered waterway system by the environmental group American Rivers, due to water shortages caused by the Delta's environmental problems, declining fish populations and aging levees, among other problems.
Major tributaries
- San Joaquin RiverSan Joaquin RiverThe San Joaquin River is the largest river of Central California in the United States. At over long, the river starts in the high Sierra Nevada, and flows through a rich agricultural region known as the San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean...
- Sacramento RiverSacramento RiverThe Sacramento River is an important watercourse of Northern and Central California in the United States. The largest river in California, it rises on the eastern slopes of the Klamath Mountains, and after a journey south of over , empties into Suisun Bay, an arm of the San Francisco Bay, and...
- American RiverAmerican RiverThe American River is a California watercourse noted as the site of Sutter's Mill, northwest of Placerville, California, where gold was found in 1848, leading to the California Gold Rush...
- Mokelumne RiverMokelumne RiverThe Mokelumne River is a river in Northern California. The Upper Mokelumne River originates in the Sierra Nevada mountain range and flows into Pardee Reservoir and then Camanche Reservoir in the Sierra foothills. The Lower Mokelumne River refers to the portion of the river below Camanche Dam...
- Calaveras RiverCalaveras RiverThe Calaveras River is a river in the California Central Valley. It flows roughly southwest for from the confluence of its north and south forks in Calaveras County to its confluence with the San Joaquin River just west of the city of Stockton....
Islands
- Category: Islands of the Sacramento-San Joaquin Delta
See also
- CALFED Bay-Delta ProgramCALFED Bay-Delta ProgramThe CALFED Bay-Delta Program, also known as CALFED, is a department within the government of California, administered under the California Resources Agency. The department acts as consortium, coordinating the activities and interests of the state government of California and the U.S...
- John P. IrishJohn P. IrishJohn Powell Irish, known as John P. Irish, was a leader of the Democratic Party in Iowa, a landowner in the Sacramento-San Joaquin Delta region of California, a fiery and influential public speaker, and an opponent of prejudice against Japanese, the Chinese Exclusion Act of 1882, women's suffrage ...
, Delta landowner
External links
- California Delta Chambers and Visitors Bureau
- Delta Wetlands Project
- Sacramento-San Joaquin Delta Atlas at California Department of Water ResourcesCalifornia Department of Water ResourcesThe California Department of Water Resources , is a department within the California Natural Resources Agency. The Department of Water Resources is responsible for the State of California's management and regulation of water usage...
- What is this place called the Delta? (slideshow)
- Delta Waterways at California Department of Water ResourcesCalifornia Department of Water ResourcesThe California Department of Water Resources , is a department within the California Natural Resources Agency. The Department of Water Resources is responsible for the State of California's management and regulation of water usage...
- SFGate: Deluge in the Delta (4 Jun 2004)
- Cnet -- Visiting SF Bay (and delta) in a warehouse. Article by Daniel Terdimen, photos by James Martin, Cnet News, Aug 27, 2007
- Cnet -- Barge-scale cleanup in California waterways (photos), by James Martin, March 20, 2010
- Cnet -- Engineering a massive cleanup of toxic waterways (photos), by James Martin, March 20, 2010
- San Joaquin Delta Land Reclamation Photographs, ca. 1904-1907, The Bancroft Library