San Rafael Creek
Encyclopedia
San Rafael Creek is a watercourse in Marin County, California
, USA that discharges to San Rafael Bay
, a small embayment of the San Francisco Bay
. The mouth of San Rafael Creek is a channelized estuary
through an industrial area. San Rafael Creek has a designation under Federal Law Section 303(d) as impaired by diazinon
, the principal pollutant causing impairment designations for streams discharging to San Pablo Bay
, which is the northern arm of San Francisco Bay
. In September 2007, the organization Save The Bay designated San Rafael Creek as one of the top ten 'worst trash hot spot' waterways flowing into the San Francisco Bay . The channel portion of San Rafael Creek below the Grand Street Bridge is dredged on a regular maintenance schedule to keep the shallow draft channel navigable. Dredge spoils are disposed of at a site near Alcatraz Island
.
Most of the soils in the lower watershed are clay
s and bay mud
, resulting in a low transmissivity of groundwater
. Typical vertical soil profiles in the lower watershed are four to five feet of imported fill over 60 to 65 feet (18 - 20 meter) of bay mud set on a basement of Franciscan
Sandstone
bedrock
. At the mouth of San Rafael Creek, situated on the south bank, is Pickleweed Park, where shorebirds can be seen, particularly in the winter migration
season.
Marin County, California
Marin County is a county located in the North San Francisco Bay Area of the U.S. state of California, across the Golden Gate Bridge from San Francisco. As of 2010, the population was 252,409. The county seat is San Rafael and the largest employer is the county government. Marin County is well...
, USA that discharges to San Rafael Bay
San Rafael Bay
San Rafael Bay is an embayment of San Pablo Bay, the northern portion of the larger San Francisco Bay, on the west coast of the United States....
, a small embayment 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...
. The mouth of San Rafael Creek is a channelized 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....
through an industrial area. San Rafael Creek has a designation under Federal Law Section 303(d) as impaired by diazinon
Diazinon
Diazinon , a colorless to dark brown liquid, is a thiophosphoric acid ester developed in 1952 by Ciba-Geigy, a Swiss chemical company...
, the principal pollutant causing impairment designations for streams discharging to San Pablo Bay
San Pablo Bay
San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in northern California in the United States. Most of the Bay is shallow; however, there is a deep water channel approximately in mid bay, which allows access to Sacramento, Stockton, Benicia, Martinez, and...
, which is the northern 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...
. In September 2007, the organization Save The Bay designated San Rafael Creek as one of the top ten 'worst trash hot spot' waterways flowing into the San Francisco Bay . The channel portion of San Rafael Creek below the Grand Street Bridge is dredged on a regular maintenance schedule to keep the shallow draft channel navigable. Dredge spoils are disposed of at a site near Alcatraz Island
Alcatraz Island
Alcatraz Island is an island located in the San Francisco Bay, offshore from San Francisco, California, United States. Often referred to as "The Rock" or simply "Traz", the small island was developed with facilities for a lighthouse, a military fortification, a military prison, and a Federal...
.
Most of the soils in the lower watershed are clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
s and 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...
, resulting in a low transmissivity of groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
. Typical vertical soil profiles in the lower watershed are four to five feet of imported fill over 60 to 65 feet (18 - 20 meter) of bay mud set on a basement of Franciscan
Franciscan
Most Franciscans are members of Roman Catholic religious orders founded by Saint Francis of Assisi. Besides Roman Catholic communities, there are also Old Catholic, Anglican, Lutheran, ecumenical and Non-denominational Franciscan communities....
Sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...
. At the mouth of San Rafael Creek, situated on the south bank, is Pickleweed Park, where shorebirds can be seen, particularly in the winter migration
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...
season.