Suisun Marsh
Encyclopedia
Located in northern California
the Suisun Marsh is the largest brackish marsh
on west coast of the United States of America. The marsh land is part of the San Francisco Bay
tidal estuary, and subject to tidal ebb and flood. The marsh is home to many species of birds and other wildlife, and is formed by the confluence of the Sacramento
and San Joaquin rivers
between Martinez
and Fairfield, California
and several other smaller, local watersheds. The marsh is immediately west of the legally defined Sacramento-San Joaquin Delta as well as part of the San Francisco Bay
estuary.
The Suisun Marsh is named for the Suisunes
, a Patwin sub-tribe, who inhabited the area around 200 years ago.
marshes in the western United States. Geologically, the Suisun Marsh is the product of water-borne sediment
deposition, carried from the Sacramento and San Joaquin Rivers into the San Francisco Bay. This process—the weathering of the parent rock of the Sierra Nevada and Vaca Mountains
, transport of the weathered material via rivers and creeks, and ultimate deposition into San Francisco Bay—has taken place over thousands of years and has resulted in the patchwork nature of the marsh. The marsh areas consist of peat
soils formed by the decay of emergent plants over time.
Originally, Suisun Marsh was a vast stretch of tidal wetlands broken by branching tidal channels and ponds. The area alternately flooded and drained with the rise and fall of the tides. In winter, the ponds supported high numbers of migratory waterfowl
. From the years of the Gold Rush
to about 1880, the marsh was extensively used by market hunters to provide fresh waterfowl and feathers to San Francisco markets. From the 1880s until the 1930s, however, this area was gradually converted to agriculture, made possible by the construction of levee
s and dikes to hold back the water. Eventually, increasing soil salinity made cultivation and even cattle grazing unprofitable and cultivation ceased on all wetland areas. Most of the marsh was then purchased by public and private interests as habitat for waterfowl, mainly to support hunting. Later, the construction of water development projects (specifically, the federal Central Valley Project
and the California State Water Project
) in the Sacramento-San Joaquin watersheds altered the natural salinity regime of the marsh, making it more saline. In an effort to maintain the wetlands, the marsh landowners sought legislation to preserve the area from residential or commercial development. In addition, they pursued relief from the impacts of the water projects on the salinity regime of the marsh. As a result, the parties entered into agreements to offset the impacts of the water projects on the managed wetlands. Today, Suisun Marsh supports a diversity of fish, wildlife and plants, including a large population of river otter
s, a number of native fish species, and birds ranging from Marsh Wren
s to American White Pelican
s. Rush Ranch has only been recently acquired and is managed for both historic and biological values.http://geolit.org/rushranch/rushranch.htm However, its habitats are being enhanced and many tidal marsh plants and animals can be seen there.
Rush Ranch is a 2070 acre (8.4 km²) remnant tidal marsh preserve within Suisun Marsh that was acquired for wildlife habitat and public access to the marsh by the Solano County Farmlands and Open Space Foundation in 1988. The non-profit organization, dedicated to protect and preserve farmland, ranchland and open space in Solano County, has since been renamed Solano Land Trust.
A component of the Solano Land Trust located at Rush Ranch is the Rush Ranch Educational Council, more commonly known as RREC. RREC is an all volunteer, non-profit organization that offers an educational program to 3rd and 4th grade students who visit the ranch on field trips. The program is offered at no charge, made possible by a grant from the Nature Conservancy in partnership with the Solano Land Trust. The program—designed to meet California K-12 education standards for history-social studies—teaches children about the original inhabitants of the ranch, the Patwin Indians, on a recreated Patwin village located on the ranch. The interactive program is divided into six stations, each focused on a facet of Patwin culture and daily life. At these stations, RREC docents use replicated tools and materials to demonstrate the ways in which the Patwins were able to thrive and ensure generational survival using seasonally available resources and by employing sustainable harvesting and natural resource conservation.
Another public part of the marsh is Grizzly Island Wildlife Area which is managed primarily for waterfowl, although over 230 species of birds have been seen here as well as many mammals, amphibians, reptiles, and fish. Grizzly Island has an unusually dense population of river otters, which can be seen swimming in its numerous sloughs, ponds, and roadside ditches. In the fall, the Grizzly Island Wildlife Area herd of tule elk
breeds. The bugling of bull elk can be heard especially in the early morning and evening. Access to certain areas of the Wildlife Area is limited during the first nine days of pheasant
hunting season around November, and on Wednesdays and Saturdays during the waterfowl hunting season from October through January.
Recent studies by the CALFED Suisun Marsh Levee Investigation demonstrate that the current configuration of the 230 miles of levees in the Marsh prevent salinity intrusion into the freshwater of the Delta used by 22 million people for drinking water.
The rest of the year, the ponds are flooded and drained on a schedule designed to optimize conditions for plants which provide seeds preferred by waterfowl, namely alkali bulrush, fat hen
, and brass buttons
. Ponds left flooded through at least the spring provide brood rearing habitat. The flood-and-drain cycle is also designed to minimize soil salinity by leaching and flushing salts. Today, this flood management program also supports plants such as tule
s, cattails
, saltgrass, and pickleweed, which may not yield preferred waterfowl food seeds, but do provide habitat for invertebrates important to pre-breeding waterfowl and other wildlife.
When Suisun agricultural lands reverted to wetlands, they provided habitat for waterfowl displaced decades earlier by reclamation. In addition, the presence of these "new" wetlands eased waterfowl crop depredation in the Central Valley
. It also provided habitat no longer available in the Central Valley due to extensive reclamation for agriculture and urbanization. By about 1930, waterfowl hunting had become the primary use of the Suisun Marsh. It is the dominant use today, with 158 private duck clubs and large public hunting areas.
The flood tide pushing through the slough takes half an hour longer to traverse the marsh than does the matching flood tide following the more direct route in the main Suisin Bay channel. Thus, high tide at the east end of the slough arrives out of phase with high tide in the main channel, and rather than being pushed back, as it would be in the main channel or in a dead-end slough, the slough water keeps flowing eastward, drawing more saline water with it.
To meet the salinity requirements stipulated by the California Water Resources Control Board to support "beneficial uses" in Decision-1485, the California State Water Project and the federal Central Valley Project built the Montezuma Slough Salinity Control Gates. They began operation in 1989. The gates span Montezuma Slough near the Roaring River intake and are periodically operated from October to May to meet the more recently established salinity standards set by Decision-1641, to block the salty flood tide from Grizzly Bay but allow passage of the freshwater ebb tide from the mouth of the Sacramento-San Joaquin Delta.
Because the Salinity Control Gates are more effective than anticipated other proposed salinity control measures were abandoned. The gates operate as needed from October through May.
. Monitoring stations throughout the marsh measure the impact of water management activities on fish populations, and fish screens prevent the diversion and entrapment of fish in the waterfowl ponds.
The Marsh supports 80% of the state's commercial salmon fishery by providing important tidal rearing areas for juvenile fish allowing them to grow twice as fast as those reared in the upper watershed, thus, greatly enhancing their survival. And is an important area for native fishes including the delta smelt
which is protected by the federal Endangered Species Act
.
, a variety of thistle which is a federally listed endangered species
.
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...
the Suisun Marsh is the largest brackish marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
on west coast of the United States of America. The marsh land is part of 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...
tidal estuary, and subject to tidal ebb and flood. The marsh is home to many species of birds and other wildlife, and is formed 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 rivers
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...
between Martinez
Martinez, California
Martinez is a city and the county seat of Contra Costa County, California, United States. The population was 35,824 at the 2010 census. The downtown is notable for its large number of preserved old buildings...
and Fairfield, California
Fairfield, California
Fairfield is a city located in Solano County in Northern California, USA. It is generally considered the midpoint between the cities of San Francisco and Sacramento, approximately from the city center of both cities, approximately from the city center of Oakland, less than from Napa Valley, 18...
and several other smaller, local watersheds. The marsh is immediately west of the legally defined Sacramento-San Joaquin Delta as well as part of 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...
estuary.
The Suisun Marsh is named for the Suisunes
Suisunes
The Suisunes were a tribe of Native Americans that lived in Northern California's Suisun Marsh regions of Solano County, California between what is now Suisun City, Vacaville and Putah Creek around 200 years ago. The Suisunes' main village, Yulyul, is believed to be where Rockville, California is...
, a Patwin sub-tribe, who inhabited the area around 200 years ago.
Overview
Suisun Marsh, 116,000 acres (470 km²) of land, bays, and sloughs, is one of the largest estuarineEstuary
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....
marshes in the western United States. Geologically, the Suisun Marsh is the product of water-borne sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
deposition, carried from the Sacramento and San Joaquin Rivers into the San Francisco Bay. This process—the weathering of the parent rock of the Sierra Nevada and Vaca Mountains
Vaca Mountains
The Vaca Mountains are a mountain range in Napa and Solano Counties, California.-Ecology:A variety of flora and fauna occur in the Vaca Mountains, including tree species such as Blue oak and Leather oak, the latter occurring outside of its typical range....
, transport of the weathered material via rivers and creeks, and ultimate deposition into San Francisco Bay—has taken place over thousands of years and has resulted in the patchwork nature of the marsh. The marsh areas consist of 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...
soils formed by the decay of emergent plants over time.
Originally, Suisun Marsh was a vast stretch of tidal wetlands broken by branching tidal channels and ponds. The area alternately flooded and drained with the rise and fall of the tides. In winter, the ponds supported high numbers of migratory waterfowl
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
. From the years of the Gold Rush
California Gold Rush
The California Gold Rush began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The first to hear confirmed information of the gold rush were the people in Oregon, the Sandwich Islands , and Latin America, who were the first to start flocking to...
to about 1880, the marsh was extensively used by market hunters to provide fresh waterfowl and feathers to San Francisco markets. From the 1880s until the 1930s, however, this area was gradually converted to agriculture, made possible by the construction 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 and dikes to hold back the water. Eventually, increasing soil salinity made cultivation and even cattle grazing unprofitable and cultivation ceased on all wetland areas. Most of the marsh was then purchased by public and private interests as habitat for waterfowl, mainly to support hunting. Later, the construction of water development projects (specifically, the federal 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...
and the California State Water Project
California State Water Project
The California State Water Project, commonly known as the SWP , is the world's largest publicly built and operated water and power development and conveyance system. The SWP was designed and is operated by the California Department of Water Resources...
) in the Sacramento-San Joaquin watersheds altered the natural salinity regime of the marsh, making it more saline. In an effort to maintain the wetlands, the marsh landowners sought legislation to preserve the area from residential or commercial development. In addition, they pursued relief from the impacts of the water projects on the salinity regime of the marsh. As a result, the parties entered into agreements to offset the impacts of the water projects on the managed wetlands. Today, Suisun Marsh supports a diversity of fish, wildlife and plants, including a large population of river otter
Northern River Otter
The North American river otter , also known as the northern river otter or the common otter, is a semiaquatic mammal endemic to the North American continent, found in and along its waterways and coasts. An adult river otter can weigh between 5 and 14 kg...
s, a number of native fish species, and birds ranging from Marsh Wren
Marsh Wren
The Marsh Wren is a small North American songbird of the wren family. It is sometimes called Long-billed Marsh Wren to distinguish it from the Sedge Wren, also known as Short-billed Marsh Wren....
s to American White Pelican
American White Pelican
The American White Pelican is a large aquatic bird from the order Pelecaniformes. It breeds in interior North America, moving south and to the coasts, as far as Central America, in winter....
s. Rush Ranch has only been recently acquired and is managed for both historic and biological values.http://geolit.org/rushranch/rushranch.htm However, its habitats are being enhanced and many tidal marsh plants and animals can be seen there.
Rush Ranch is a 2070 acre (8.4 km²) remnant tidal marsh preserve within Suisun Marsh that was acquired for wildlife habitat and public access to the marsh by the Solano County Farmlands and Open Space Foundation in 1988. The non-profit organization, dedicated to protect and preserve farmland, ranchland and open space in Solano County, has since been renamed Solano Land Trust.
A component of the Solano Land Trust located at Rush Ranch is the Rush Ranch Educational Council, more commonly known as RREC. RREC is an all volunteer, non-profit organization that offers an educational program to 3rd and 4th grade students who visit the ranch on field trips. The program is offered at no charge, made possible by a grant from the Nature Conservancy in partnership with the Solano Land Trust. The program—designed to meet California K-12 education standards for history-social studies—teaches children about the original inhabitants of the ranch, the Patwin Indians, on a recreated Patwin village located on the ranch. The interactive program is divided into six stations, each focused on a facet of Patwin culture and daily life. At these stations, RREC docents use replicated tools and materials to demonstrate the ways in which the Patwins were able to thrive and ensure generational survival using seasonally available resources and by employing sustainable harvesting and natural resource conservation.
Another public part of the marsh is Grizzly Island Wildlife Area which is managed primarily for waterfowl, although over 230 species of birds have been seen here as well as many mammals, amphibians, reptiles, and fish. Grizzly Island has an unusually dense population of river otters, which can be seen swimming in its numerous sloughs, ponds, and roadside ditches. In the fall, the Grizzly Island Wildlife Area herd of tule elk
Tule Elk
The tule elk is a subspecies of elk found only in California, ranging from the grasslands and marshlands of the Central Valley to the grassy hills on the coast. The subspecies name derives from the tule that it feeds off of, which grows in the marshlands...
breeds. The bugling of bull elk can be heard especially in the early morning and evening. Access to certain areas of the Wildlife Area is limited during the first nine days of pheasant
Pheasant
Pheasants refer to some members of the Phasianinae subfamily of Phasianidae in the order Galliformes.Pheasants are characterised by strong sexual dimorphism, males being highly ornate with bright colours and adornments such as wattles and long tails. Males are usually larger than females and have...
hunting season around November, and on Wednesdays and Saturdays during the waterfowl hunting season from October through January.
Recent studies by the CALFED Suisun Marsh Levee Investigation demonstrate that the current configuration of the 230 miles of levees in the Marsh prevent salinity intrusion into the freshwater of the Delta used by 22 million people for drinking water.
Flooded ponds
As noted above, the dikes, or levees, of Suisun Marsh were originally built by nineteenth century farmers seeking to create farmland from tidal marsh. While this system is still in use on the Sacramento-San Joaquin Delta islands to the east, it failed in the Suisun Marsh due to unacceptably high soil salinities. Portions of the marsh were subsequently converted from farming to permanently and seasonally flooded wetlands in the twentieth century. Today, approximately 230 miles of levees maintain seasonally and permanently flooded wetlands. Between approximately mid-October and mid-January, managed seasonal wetlands are flooded to a depth of 8 to 12 inches to attract waterfowl.The rest of the year, the ponds are flooded and drained on a schedule designed to optimize conditions for plants which provide seeds preferred by waterfowl, namely alkali bulrush, fat hen
Chenopodium album
Chenopodium album is a fast-growing weedy annual plant in the genus Chenopodium.Though cultivated in some regions, the plant is elsewhere considered a weed...
, and brass buttons
Cotula coronopifolia
The small marsh flower Cotula coronopifolia bears the common names brass buttons, golden buttons, and buttonweed. The flowers are bright yellow discoid inflorescences that look like thick buttons. Individual plants spread stems along the ground and send up the knobby flowers at intervals...
. Ponds left flooded through at least the spring provide brood rearing habitat. The flood-and-drain cycle is also designed to minimize soil salinity by leaching and flushing salts. Today, this flood management program also supports plants such as tule
Tule
Schoenoplectus acutus , called tule , common tule, hardstem tule, tule rush, hardstem bulrush, or viscid bulrush, is a giant species of sedge in the plant family Cyperaceae, native to freshwater marshes all over North America...
s, cattails
Typha
Typha is a genus of about eleven species of monocotyledonous flowering plants in the family Typhaceae. The genus has a largely Northern Hemisphere distribution, but is essentially cosmopolitan, being found in a variety of wetland habitats...
, saltgrass, and pickleweed, which may not yield preferred waterfowl food seeds, but do provide habitat for invertebrates important to pre-breeding waterfowl and other wildlife.
When Suisun agricultural lands reverted to wetlands, they provided habitat for waterfowl displaced decades earlier by reclamation. In addition, the presence of these "new" wetlands eased waterfowl crop depredation in 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...
. It also provided habitat no longer available in the Central Valley due to extensive reclamation for agriculture and urbanization. By about 1930, waterfowl hunting had become the primary use of the Suisun Marsh. It is the dominant use today, with 158 private duck clubs and large public hunting areas.
Water management
The wetland managers for both the private hunting clubs and the state's public land take water from major and minor sloughs throughout the marsh. Montezuma Slough, one of the largest, is open at both ends, and its flood tide current is longer and stronger than its ebb tide current, causing a net west-to-east flow which draws higher saline water eastward from Grizzly Bay.The flood tide pushing through the slough takes half an hour longer to traverse the marsh than does the matching flood tide following the more direct route in the main Suisin Bay channel. Thus, high tide at the east end of the slough arrives out of phase with high tide in the main channel, and rather than being pushed back, as it would be in the main channel or in a dead-end slough, the slough water keeps flowing eastward, drawing more saline water with it.
To meet the salinity requirements stipulated by the California Water Resources Control Board to support "beneficial uses" in Decision-1485, the California State Water Project and the federal Central Valley Project built the Montezuma Slough Salinity Control Gates. They began operation in 1989. The gates span Montezuma Slough near the Roaring River intake and are periodically operated from October to May to meet the more recently established salinity standards set by Decision-1641, to block the salty flood tide from Grizzly Bay but allow passage of the freshwater ebb tide from the mouth of the Sacramento-San Joaquin Delta.
Because the Salinity Control Gates are more effective than anticipated other proposed salinity control measures were abandoned. The gates operate as needed from October through May.
Fish
Although the Suisun Marsh is managed for waterfowl, it is also an important fish habitat, especially for wild salmonSalmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
. Monitoring stations throughout the marsh measure the impact of water management activities on fish populations, and fish screens prevent the diversion and entrapment of fish in the waterfowl ponds.
The Marsh supports 80% of the state's commercial salmon fishery by providing important tidal rearing areas for juvenile fish allowing them to grow twice as fast as those reared in the upper watershed, thus, greatly enhancing their survival. And is an important area for native fishes including the delta smelt
Delta 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...
which is protected by the federal Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
.
Flora
Suisun Marsh is home to the only two known occurrences of the Suisun thistle, Cirsium hydrophilum var. hydrophilumCirsium hydrophilum
Cirsium hydrophilum is a species of thistle which is endemic to California, where it is found only in the San Francisco Bay Area and the Sacramento-San Joaquin River Delta. This native thistle grows in wet boggy habitats.-Description:...
, a variety of thistle which is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.