Seal Slough
Encyclopedia
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
channel through a tidal 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....
in San Mateo
San Mateo, California
San Mateo is a city in San Mateo County, California, United States, in the San Francisco Bay Area. With a population of approximately 100,000 , it is one of the larger suburbs on the San Francisco Peninsula, located between Burlingame to the north, Foster City to the east, Belmont to the south,...
and Foster City, California
Foster City, California
Foster City is an affluent planned city located in San Mateo County, California, 94404. As of the 2010 census, the city had a total population of 30,567. Forbes ranked Foster City #10 on their 2009 list of America's Top 25 Towns to Live Well. Money has also recognized Foster City multiple times as...
. This slough
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...
has been the object of a wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
restoration
Restoration ecology
-Definition:Restoration ecology is the scientific study and practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human intervention and action, within a short time frame...
project in recent years to enhance habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
value. Dredging has been carried out in Seal Slough since at least 1954. When the original wastewater treatment
Wastewater Treatment
Wastewater treatment may refer to:* Sewage treatment* Industrial wastewater treatment...
plant for the city of San Mateo was constructed in 1935, its discharge was directed to Seal Slough.
The marshy area through which Seal Slough meanders is a productive brackish
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
wetland whose dominant flora
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...
is cordgrass
Cordgrass
Spartina, commonly known as cordgrass or cord-grass, is a genus of 14 species of grasses in the family Poaceae. They are native to the coasts of the Atlantic Ocean in western and southern Europe, northwest and southern Africa, the Americas and the southern Atlantic Ocean islands; one or two species...
. There are a number of significant wildlife
Wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....
features associated with Seal Slough, including use by the endangered
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...
California Clapper Rail
California Clapper Rail
The California Clapper Rail is an endangered subspecies of the Clapper Rail . It is found principally in California's San Francisco Bay, and also in Monterey Bay and Morro Bay...
. A tide gate near the mouth of Seal Slough regulates tidal influx from 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...
to the Marina Lagoon; this flushing action is important to prevent population explosion
Overpopulation
Overpopulation is a condition where an organism's numbers exceed the carrying capacity of its habitat. The term often refers to the relationship between the human population and its environment, the Earth...
of midge
Midge
A midge is a very small, two-winged flying insect. "Midge" may also refer to:-Real:* Midge Costanza , American politician* Mildred Gillars , aka "Midge", American broadcaster of Nazi propaganda during World War II...
s in the local area.
Course
Seal Slough has a tidal exchange with San Francisco Bay on the eastern shoreShore
A shore or shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In Physical Oceanography a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore,...
line of the city of San Mateo, approximately mid-way between Coyote Point and the San Mateo Bridge. At its mouth
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...
there is a marshy area and an extent of bay mud
Bay mud
Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles...
extending approximately 700 meters northward into San Francisco Bay. Near the mouth area is situated the city of San Mateo Wastewater Treatment Plant
Sewage treatment
Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...
and Bayside School. The course of the slough is highly tortuous as it winds easterly. Further along its course continuing eastward, single-family residential uses have encroached closely on its southern banks; in this middle reach it also passes close to and north of Parkside School. Further to the east it passes beside Lakeshore School before crossing under Hillsdale Boulevard and entering Foster City.
Ecology
Much of the information regarding Seal slough was developed in a 1980 study, in which CaltransCalifornia Department of Transportation
The California Department of Transportation is a government department in the U.S. state of California. Its mission is to improve mobility across the state. It manages the state highway system and is actively involved with public transportation systems throughout the state...
and the city retained Earth Metrics to analyze impacts of a new bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
across Seal Slough at East Third Avenue. The most significant habitat area along Seal Slough is the tidal mouth
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...
, where there are three identified plant community zones. The lowest zone is defined by the presence of mudflat
Mudflat
Mudflats or mud flats, also known as tidal flats, are coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of...
s and/or the dominant plant cordgrass
Cordgrass
Spartina, commonly known as cordgrass or cord-grass, is a genus of 14 species of grasses in the family Poaceae. They are native to the coasts of the Atlantic Ocean in western and southern Europe, northwest and southern Africa, the Americas and the southern Atlantic Ocean islands; one or two species...
, distichlis
Distichlis
Distichlis is a genus of grasses in the family Poaceae.-Selected species:* Distichlis bajaensis H.L.Bell – Baja Grass* Distichlis littoralis...
sp. The middle zone is characterized by the dominant plant pickleweed, Salicornia sp., and the upper zone, which is the most disturbed, is characterized by salt grass, Distichlis spicata, and by peripheral halophyte
Halophyte
A halophyte is a plant that grows where it is affected by salinity in the root area or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs, and seashores. An example of a halophyte is the salt marsh grass Spartina alterniflora . Relatively few plant species are...
s (salt tolerant plants). The pickleweed community thrives primarily on the north banks of Seal Slough. Cordgrass and pickleweed habitats are among the most productive types in the state of California, in each case producing over five tons of organic material per acre per annum. Further these plants supply the adjacent mudflats with detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
that is the basis of estuarine
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....
food chain
Food chain
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
s.
Cordgrass is also used for food and cover for a multiplicity of waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
, including the endangered California Clapper Rail
California Clapper Rail
The California Clapper Rail is an endangered subspecies of the Clapper Rail . It is found principally in California's San Francisco Bay, and also in Monterey Bay and Morro Bay...
, which species occurs in Seal Slough. Other avafauna found in this robust wetland include killdeer
Killdeer
The Killdeer is a medium-sized plover.Adults have a brown back and wings, a white belly, and a white breast with two black bands. The rump is tawny orange. The face and cap are brown with a white forehead. They have an orange-red eyering...
, mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
s and the snowy egret
Snowy Egret
The Snowy Egret is a small white heron. It is the American counterpart to the very similar Old World Little Egret, which has established a foothold in the Bahamas....
. The Seal Slough mudflats also provide a feeding area at high tides for a variety of fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es including top smelt, anchovy
Anchovy
Anchovies are a family of small, common salt-water forage fish. There are 144 species in 17 genera, found in the Atlantic, Indian, and Pacific Oceans. Anchovies are usually classified as an oily fish.-Description:...
, bat ray
Bat ray
The bat ray, Myliobatis californica, is an eagle ray found in muddy or sandy sloughs, estuaries and bays, kelp beds and rocky-bottomed shoreline in the eastern Pacific Ocean, between the Oregon coast and the Gulf of California. It is also found in the area around the Galápagos Islands. The largest...
, leopard shark
Leopard shark
The leopard shark is a species of houndshark, family Triakidae, found along the Pacific coast of North America from the U.S. state of Oregon to Mazatlán in Mexico...
, spiny dogfish
Spiny dogfish
The spiny dogfish, spurdog, mud shark, or piked dogfish, Squalus acanthias, is one of the best known of the dogfish which are members of the family Squalidae in the order Squaliformes. While these common names may apply to several species, Squalus acanthias is distinguished by having two spines ...
, striped bass
Striped bass
The striped bass is the state fish of Maryland, Rhode Island, South Carolina, and the state saltwater fish of New York, Virginia, and New Hampshire...
and longjaw mudsucker
Longjaw mudsucker
The longjaw mudsucker Gillichthys mirabilis is a goby of the Pacific Ocean coast of California and Baja California, noted for its extremely large mouth and ability to survive out of water for short periods....
.