Linking selenium sources to ecosystems: San Francisco Bay-Delta Model

Fact Sheet 2004-3091
By:  and 



Marine sedimentary rocks of the Coast Ranges contribute selenium to soil, surface water, and ground water in the western San Joaquin Valley, California. Irrigation funnels selenium into a network of subsurface drains and canals. Proposals to build a master drain (i.e., San Luis Drain) to discharge into the San Francisco Bay-Delta Estuary remain as controversial today as they were in the 1950s, when drainage outside the San Joaquin Valley was first considered. An existing 85-mile portion of the San Luis Drain was closed in 1986 after fish mortality and deformities in ducks, grebes and coots were discovered at Kesterson National Wildlife Refuge, the temporary terminus of the drain. A 28-mile portion of the drain now conveys drainage from 100,000 acres into the San Joaquin River and eventually into the Bay-Delta. If the San Luis Drain is extended directly to the Bay-Delta, as is now being proposed as an alternative to sustain agriculture, it could receive drainage from an estimated one-million acres of farmland affected by rising water tables and increasing salinity. In addition to agricultural sources, oil refineries also discharge selenium to the Bay-Delta, although those discharges have declined in recent years. To understand the effects of changing selenium inputs, scientists have developed the Bay-Delta Selenium Model.

Study Area

Publication type Report
Publication Subtype USGS Numbered Series
Title Linking selenium sources to ecosystems: San Francisco Bay-Delta Model
Series title Fact Sheet
Series number 2004-3091
DOI 10.3133/fs20043091
Year Published 2004
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Toxic Substances Hydrology Program
Description 4 p.
Country United States
State California
Other Geospatial San Francisco Bay delta
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