Los Vaqueros Reservoir

The Los Vaqueros Reservoir is located in the northern Diablo Range, within northeastern Contra Costa County, northern California.

It was completed by the Contra Costa Water District (CCWD) in 1998 to improve the quality of drinking water for its 550,000 customers in Central and Eastern Contra Costa County.

The reservoir is accessible via Vasco Road which connects Brentwood and Livermore. An expansion project begun in 2010 raised the height of the dam to increase storage capacity from 100,000 acre-ft to 160,000 acre-ft of water.

History

Los Vaqueros Reservoir is named for the 19th century Mexican Rancho Cañada de los Vaqueros land grant that included its site. The Spanish word vaquero means "cowboy" in English.

Incursions of saline water into the Sacramento-San Joaquin River Delta from the San Francisco Bay has been a concern since the 1870s. This concern was one of the reasons CCWD was formed in 1936. A drought in 1977, caused salinity levels to exceed public health standards. It forced CCWD to ration deliveries of fresh water to its customers.^[2]

Project requirements

In 1988, voters approved funding of the Los Vaqueros Reservoir project to begin design and construction. It was a massive project. In addition to building the $61 million, 192-foot-tall dam, the district had to:

• build 12.8 miles of Vasco Road around the watershed at a cost of $27 million
• relocate 20 electrical towers and 12 miles of gas line
• build a new $20 million 10,000 horsepower pumping plant on Old River near Discovery Bay
• construct a new $12 million transfer station with 8,000 horsepower pumps
• build 20 miles of 6- to 8- foot diameter buried pipeline connecting all the new facilities with district's existing canal system in Antioch
• secure nearly 20,000 acres land for the dam and the watershed.
• make a commitment to preserving the environment and respecting Native American and other historical sites in the watershed.^[2]

Construction timeline

Construction began Sept. 17, 1994.^[2]

By 1996, Vasco Road had been relocated around the eastern edge of the CCWD property. The original road was closed to travelers from just south of Marsh Creek Road to the present Los Vaqueros Road. Half of the pipeline from Old River to Discovery Bay had also been completed. Construction of the pump station was in progress.^[2]

The dam and most of the other major items were completed by December 1997. Filling of the reservoir with water began in February 1998, and was completed by January 1999, a year ahead of schedule.^[2]

The project dedication ceremony occurred in May 1998. The American Society of Civil Engineers named the project as the "Outstanding Civil Engineering Accomplishment" in the nation in that year.^[2]

2010 - 2012 expansion project

In March, 2010, CCWD approved a capacity increase of 60,000 acre feet (74,000,000 m³).^[3] Costs will be passed on to those that receive water from the water District. Mitigation for the loss of sensitive wildlife habitat will be necessary. This increase is scheduled for completion in 2012. On July 14, 2012, the following portions of the expansion project were opened to the public:

• Addition of the John Muir Interpretive Center at the north end of the reservoir;
• Provision of trails and shoreline fishing at the south end of the reservoir.^[4]

The south end of the reservoir reopened in October 2012, after revamping the marina.^[5]

Watershed Description

The Los Vaqueros watershed comprises 19,300 acres (78 km²) of open space surrounding the 1,500-acre (6.1 km²) reservoir. Water is pumped into the reservoir from a Delta intake on Old River in the Sacramento-San Joaquin Delta. The intake is located just east of Discovery Bay. Water is pumped into the reservoir when salinity is low, and used for drinking water when salinity in the Delta is too high. Water from the reservoir is released via a pipeline to the 48-mile (77 km) Contra Costa Canal, which conveys water to six water treatment plants throughout the Water District's service area. The reservoir can store up to 100,000 acre feet (120,000,000 m³) of water. The earthen dam is 192 feet (59 m) high with a 1,000-foot (300 m) crest length. It is made of 2.7 million cubic yards of fill material.

The Watershed also serves as a weather data collection site for Mallory Ridge weather station located at the top of the ridge above the Marina. The station has a remote access water station (RAWS), which is maintained by the Los Vaqueros Watershed Staff and linked to the National Fire Weather System.^[6]

Other benefits of the reservoir include water storage for drought or emergencies, a protected open space, and recreation. There are 55 miles (89 km) of hiking trails in the watershed. The watershed is open for fishing, hiking and other activities year-round. Electric rental boats are available, but no outside boats can be launched on the lake.^[7] There is no swimming in the reservoir.

Wildlife protection

Another benefit is the protection of nearly 20,000 acres (81 km²) of wildlife habitat in Eastern Contra Costa County. The watershed is currently home for many rare, threatened and endangered species including fairy shrimp, bald and golden eagles, Alameda whipsnake, western pond turtle, California tiger salamander, California red-legged frog, San Joaquin kit fox, and the San Francisco dusky-footed wood rat. It also provides habitat for hundreds of common plant and animal species in the area. Strict environmental commitments with State and federal agencies, and a commitment to preserving the resource help preserve this site.

See also

• List of dams and reservoirs in California
• List of lakes in the San Francisco Bay Area

References

External links

• Los Vaqueros page on Conta Costa Water District web site
• Los Vaqueros fishing information
• Los Vaqueros webcam & weather
• Los Vaqueros fishing records
• "Topographic map of Los Vaqueros Reservoir" (PDF).  (407 KB)
• Los Vaqueros Project History