Background
The Mokelumne River originates in the Sierra Nevada mountain range and flows into Camanche Reservoir in the Sierra foothills. The Lower Mokelumne River crosses California's Central Valley, flowing westward through Lodi, California, and ultimately meeting its confluence with the San Joaquin River in the Sacramento-San Joaquin River Delta. The river crosses or forms the border of four California counties: Amador, Calaveras, San Joaquin, and Sacramento.
The East Bay Municipal Utility District (EBMUD), colloquially referred to as "EBMUD", "East Bay Mud" or sometimes just pronounced as "ebmud", provides water and sewage treatment for customers in portions of Alameda County and Contra Costa County in California, on the eastern side of San Francisco Bay (including the cities of Oakland, Berkeley and several nearby suburbs).
Hydroelectric energy, developed by the predecessors of the Pacific Gas and Electric Company, was exported from the Mokelumne River basin to the San Francisco East Bay Area beginning in 1902. In 1929, water itself reached the East Bay Area when EBMUD completed Pardee Dam and the 82-mile long Mokelumne Aqueduct. With completion of EBMUD’s Camanche Reservoir Project (downstream of Pardee) in the late-1960s, EBMUD turned its attention to fishery issues in the lower Mokelumne River. EBMUD built a hatchery immediately downstream of Camanche which the California Department of Fish and Game operates.
Chinook salmon returns to the Mokelumne River, an indicator of the ecological health of the river ecosystem, were non-existent in some years as a result of mining activity and waste pollution. After cessation of active mining in the 1940s, salmon returns increased, only to decline to about 400 fish during the 1976-77 and 1987-92 droughts. Flow and non-flow ecosystem restoration efforts begun in 1992 by EBMUD, the California Department of Fish and Game, the U.S. Fish and Wildlife Service, Woodbridge Irrigation District, and other interested stakeholders have improved the fishery habitat. Salmon returns over the past several years have greatly exceeded the 3,812 fish long-term annual average.
Fisheries Monitoring
Juvenile Monitoring
Adult Monitoring
Other Fisheries Monitoring
EBMUD conducts seining and electrofishing surveys annually to monitor fish abundance and distribution from the confluence with the San Joaquin to the base of Camanche Dam. Seining is conducted monthly from January through June, whereas electrofishing (backback and/or boat) is conducted four times annually. Annual reports often cover a five year period.