Nicasio Reservoir is a shallow, artificial

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

in the Nicasio Valley region of

Marin County, California Marin County is a County (United States), county located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 United States Census, 2020 census, the population was 262,231. Its county seat and ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It covers and sits in a drainage basin. It was created by the construction of Seeger Dam on the

Nicasio Creek Nicasio Creek is an U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed March 9, 2011 stream in Marin County, California, United States and is the primary tributary of Lagunitas Creek, which ...

in 1961. Seeger Dam is a tall, long earthen dam owned by the

Marin Municipal Water District The Marin Municipal Water District (or MMWD) is the government agency that provides drinking water to southern and central Marin County, California. Chartered in 1912, it became California's first municipal water district. It serves 191,000 custom ...

Controversy

The construction in the dam aroused much controversy among longtime residents of the area. The Water District forced the displacement of many

farm A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is used fo ...

s, including the McIsaac family farm and the Tomasini Ranch, on which the majority of the reservoir sits. The controversy stems from the fact the water from the reservoir is rarely used by the Water District, that the broad and shallow nature of the reservoir leads to quick evaporation, and that the dam has blocked valuable spawning areas for endangered

coho salmon The coho salmon (''Oncorhynchus kisutch;'' Karuk: achvuun) is a species of anadromous fish in the salmon family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon or "silvers". The scientific species name i ...

and threatened

steelhead trout Steelhead, or occasionally steelhead trout, is the common name of the anadromous form of the coastal rainbow trout or redband trout (O. m. gairdneri). Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and N ...

. Construction of Seeger Dam wiped out the salmon population in Nicasio Creek. The District briefly attempted to trap salmon below the dam and transport them by truck further up

and Halleck Creek. However, the effort proved unsuccessful.

Ecology

A river otter (''Lontra canadensis'') was collected by the

Museum of Vertebrate Zoology The Museum of Vertebrate Zoology is a natural history museum at the University of California, Berkeley. The museum was founded by philanthropist Annie Montague Alexander in 1908. Alexander recommended zoologist Joseph Grinnell as museum director, ...

at the southwest corner of Nicasio Reservoir in January, 2008.

Recreational uses

The reservoir is used for recreational purposes; mainly

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...

and

hiking Hiking is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century.AMATO, JOSEPH A. "Mind over Foot: Romantic Walking and Rambling." In ''On Foot: A Histor ...

Largemouth bass The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...

, carp and catfish are caught in the lake. There are problems with illegal poaching. The

California Office of Environmental Health Hazard Assessment The Office of Environmental Health Hazard Assessment, commonly referred to as OEHHA (pronounced oh-EEE-ha), is a specialized department within the cabinet-level California Environmental Protection Agency ( CalEPA) with responsibility for evaluatin ...

(OEHHA) has developed a safe eating advisory for fish caught in Nicasio Reservoir based on levels of mercury or

PCBs Polychlorinated biphenyls (PCBs) are highly carcinogenic chemical compounds, formerly used in industrial and consumer products, whose production was banned in the United States by the Toxic Substances Control Act in 1979 and internationally by t ...

found in the fish species.

References

{{authority control Reservoirs in Marin County, California West Marin Reservoirs in California Reservoirs in Northern California

Controversy

Ecology

Recreational uses

See also

References