Briones Reservoir

Last updated
Briones Reservoir
Aerial view of Briones Reservoir in California.jpg
Relief map of California.png
Red pog.svg
Briones Reservoir
Usa edcp relief location map.png
Red pog.svg
Briones Reservoir
Location Briones Hills,
Contra Costa County, California
Coordinates 37°54′54″N122°12′18″W / 37.915°N 122.205°W / 37.915; -122.205 Coordinates: 37°54′54″N122°12′18″W / 37.915°N 122.205°W / 37.915; -122.205
Lake type Reservoir
Primary outflows Terminal (evaporation)
Catchment area 22 km2 (8.5 sq mi)
Basin  countries United States
Water volume 60,510 acre⋅ft (74,640,000 m3)
References [1]

Briones Reservoir is an open cut terminal water storage reservoir located in western Contra Costa County, in the East Bay region of the San Francisco Bay Area, California.


It is owned and operated by the East Bay Municipal Utility District (EBMUD).


The reservoir is in the Briones Hills, on the west side of Briones Regional Park and northeast of Orinda. It is impounded by Briones Dam, an earthen dam completed in 1964. [2] The reservoir is the largest of EBMUD’s five East Bay terminal reservoirs, with a total capacity of 60,510 acre⋅ft (74,640,000 m3), and it has a total watershed of 8.59 square miles (22 km²).

Briones Reservoir and Briones Dam in the Briones Hills. Briones Dam.jpg
Briones Reservoir and Briones Dam in the Briones Hills.

Water Source

The Briones Reservoir has two sources for its water, one local and one imported.

Its watershed of 22 km² includes the Bear Creek drainage. Bear Creek formerly flowed down the valley, which the reservoir partially submerges, and still enters from the eastern section. [3]

The major water source into the Briones Reservoir is imported from the Briones Diversion Works near Orinda. It is delivered through the Briones Aqueduct, a 7-foot, 6-inch steel pipe, operated by four pumps that can deliver up to 60 million gallons a day. [4] This is water imported from EDMUD’s biggest water source, the Mokelumne River in the San Joaquin Valley.

Water then leaves Briones Reservoir and flows to the lower part of the valley and into San Pablo Reservoir. From there, the water is distributed by a pumping plant in Kensington.


Because the water in the reservoir is mainly for human potable water uses, EBMUD is very strict about recreational activities. Fishing, swimming, and wading are not allowed. However, college rowing teams from Mills College, UC Berkeley and Saint Mary's College have permission to use the lake under certain rules, such as the inspection of all boats before use on the lake in order to prevent contamination.

Two trails, the Bear Creek Trail and the Oursan Trail, together form a 14-mile (23 km) hiking trail loop that circumnavigates the reservoir. The trailhead is at the Bear Creek Staging Area, which is within Briones Regional Park. [5] A Trail Use Permit issued by EBMUD is required for all hikers, which can be obtained online at the EBMUD website for $10. No mountain biking is permitted on the trail. Horseback riding is allowed. Dogs are allowed on the Oursan Trail segment only, and must be leashed.


See also

Related Research Articles

East Bay Municipal Utility District

East Bay Municipal Utility District (EBMUD), colloquially referred to as "East Bay Mud", is a public utility district which provides water and sewage treatment services for an area of approximately 331 square miles (860 km2) in the eastern side of the San Francisco Bay. As of 2018, EBMUD provides drinking water for approximately 1.4 million people in portions of Alameda County and Contra Costa County in California, including the cities of Richmond, El Cerrito, Hercules, San Pablo, Pinole, Lafayette, Moraga, Orinda, Danville, Oakland, Piedmont, Emeryville, Berkeley, Albany, Alameda, San Leandro, neighboring unincorporated regions, and portions of cities such as Hayward and San Ramon. Sewage treatment services are provided for 685,000 people in an 88-square-mile area. EBMUD currently has an average annual growth rate of 0.8% and is projected to serve 1.6 million people by 2030. Headquartered in Oakland, EBMUD owns and maintains 2 water storage reservoirs on the Mokelumne River, 5 terminal reservoirs, 91 miles (146 km) of water transmission aqueducts, 4,100 miles (6,600 km) of water mains, 6 water treatment plants (WTPs), 29 miles (47 km) of wastewater interceptor sewer lines and a regional wastewater treatment facility (WWTF) rated at a maximum treatment capacity of 320 MGD.

Mokelumne River River in northern California

The Mokelumne River is a 95-mile (153 km)-long river in northern California in the United States. The river flows west from a rugged portion of the central Sierra Nevada into the Central Valley and ultimately the Sacramento–San Joaquin River Delta, where it empties into the San Joaquin River-Stockton Deepwater Shipping Channel. Together with its main tributary, the Cosumnes River, the Mokelumne drains 2,143 square miles (5,550 km2) in parts of five California counties. Measured to its farthest source at the head of the North Fork, the river stretches for 157 miles (253 km).

Alameda Creek

Alameda Creek is a large perennial stream in the San Francisco Bay Area. The creek runs for 45 miles (72 km) from a lake northeast of Packard Ridge to the eastern shore of San Francisco Bay by way of Niles Canyon and a flood control channel.

Sawyer Camp Trail

Sawyer Camp Trail is a popular 6-mile (9.7 km) trail located in the San Andreas Fault rift valley in San Mateo County, California near Hillsborough and the San Mateo Highlands. Officially, it is a segment of the longer Crystal Springs Regional Trail. Approximately 300,000 people use the trail every year. It provides excellent views of San Francisco Peninsula's Crystal Springs Watershed. The trail is managed by San Mateo County and totally surfaced in asphalt. There is considerable biodiversity along the trail due to the variation in habitat and the presence of serpentine soils. In particular the plant communities of Northern coastal scrub, grassland and California oak woodland are present.

Kennedy Grove Regional Recreation Area,(KGRRA), also known simply as Kennedy Grove, is located in West Contra Costa County, California at the base of San Pablo Dam. The nearest city is El Sobrante, California. Created in 1967, it contains a three-mile hiking trail with an elevation of 760 feet (230 m). The Grove features many large eucalyptus trees, picnic areas, volleyball nets, playgrounds, and horseshoe pits. Bird watching is popular here because hawks are almost always spotted. Some hikers have reported seeing golden and bald eagles around the reservoir. There is no camping allowed. Parking is $5 with an extra $2 fee for a dog. Dogs have to be on the leash around the lawn but they are allowed off the leash in remote parts of the park. The park is open from 8 a.m. to dusk.

Briones Regional Park

Briones Regional Park is a 6,117-acre (24.75 km2) regional park in the East Bay Regional Park District (EBRPD) system, located in the Briones Hills of central Contra Costa County of the San Francisco Bay Area in California.

San Pablo Reservoir

The San Pablo Reservoir is an open cut terminal water storage reservoir owned and operated by the East Bay Municipal Utility District (EBMUD). It is located in the valley of San Pablo Creek, north of Orinda, California, United States, and south of El Sobrante and Richmond, east of the Berkeley Hills between San Pablo Ridge and Sobrante Ridge.

Cull Canyon Regional Recreation Area (CCRRA) is a regional park located in Castro Valley, Alameda County, California. It is part of the East Bay Regional Park District (EBRPD) system.

Las Trampas Regional Wilderness

Las Trampas Regional Wilderness is a 5,342-acre (21.62 km2) regional park located in Alameda and Contra Costa counties in Northern California. The nearest city is Danville, California. Las Trampas is Spanish for the traps, or the snares. The park belongs to the East Bay Regional Park District (EBRPD).

San Pablo Creek

San Pablo Creek is an 18.7-mile-long (30.1 km) creek in Contra Costa County, California, United States, which drains the canyon or valley between the San Pablo Ridge and the Sobrante Ridge, parts of the Pacific Coast Ranges east of San Francisco Bay.

Pinole Creek

Pinole Creek is a stream in western Contra Costa County, in the East Bay region of the San Francisco Bay Area, California.

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, and the reservoir is accessible via Vasco Road, a road which connects Brentwood and Livermore.

Uvas Reservoir

Uvas Reservoir is an artificial lake located west of San Martin, California in the United States. The reservoir is surrounded by a 626-acre (253 ha) park managed by the Santa Clara County Parks and Recreation Department. The park provides limited fishing ("catch-and-release"), picnicking, and hiking activities. Boating is not permitted in the reservoir.

Lafayette Reservoir

The Lafayette Reservoir is an open-cut human-made terminal water storage reservoir owned and operated by the East Bay Municipal Utility District (EBMUD). Completed in 1933, it was intended solely as a standby water supply for EBMUD customers. EBMUD opened the reservoir for public recreation in 1966. It is located off of California State Route 24 and a mile from the Lafayette BART station, in Contra Costa County, California, United States. This all-year, day-use area is ideal for hiking, jogging, fishing, boating and picnicking. The reservoir is on the Lafayette-Orinda border. The reservoir is on a 925-acre (3.74 km2) site and holds 1.4 billion US gallons (5,300,000 m3)

Pardee Dam Dam in Sierra Nevada FoothillsAmador County, California Calaveras County, California

Pardee Dam is a 345-foot (105 m)-high structure across the Mokelumne River which marks the boundary between Amador and Calaveras Counties, located in the foothills of the Sierra Nevada approximately 30 miles (48 km) northeast of Stockton.

Briones Hills Location in the San Francisco Bay Area, California, United States

The Briones Hills form a low mountain range in western Contra Costa County, in the East Bay region of the San Francisco Bay Area, California, United States.

Rancho Boca de la Cañada del Pinole was a 13,316-acre (53.89 km2) Mexican land grant in present-day Contra Costa County, California given in 1842 by Governor Juan Alvarado to María Manuela Valencia. The name means "Mouth of the Pinole Valley" in Spanish. The rancho located between present-day Martinez, Pleasant Hill, Orinda, and Lafayette.

Mokelumne Aqueduct

The Mokelumne Aqueduct is a 95-mile (153 km) water conveyance system in central California, United States. The aqueduct is supplied by the Mokelumne River and provides water to 35 municipalities in the East Bay in the San Francisco Bay Area. The aqueduct and the associated dams, pipelines, treatment plants and hydroelectric system are owned and operated by the East Bay Municipal Utility District (EBMUD) and provide over 90 percent of the water used by the agency.

Marsh Creek (California)

Marsh Creek is a stream in east Contra Costa County, California in Northern California which rises on the eastern side of Mount Diablo and flows 30 miles (48 km) to the Sacramento–San Joaquin River Delta at Oakley, California, near Big Break Regional Shoreline. The creek flows through Marsh Creek State Park (California), where water is impounded to form Marsh Creek Reservoir, then through the city of Brentwood, California.

Upper San Leandro Reservoir

Upper San Leandro Reservoir is an artificial lake in Alameda County and Contra Costa County, California which provides water for the East Bay Municipal Utility District (EBMUD). It is impounded by the earth-filled San Leandro Dam on San Leandro Creek, located at the southeast end of the lake.


  1. U.S. Geological Survey Geographic Names Information System: Briones Reservoir
  2. "Dams Within the Jurisdiction of the State of California (A-G)" (PDF). California Department of Water Resources, Division of Safety of Dams. Archived from the original (PDF) on 2012-03-09. Retrieved November 1, 2012.CS1 maint: discouraged parameter (link)
  3. Bay Nature. Apr-Jun2014, Vol. 14 Issue 2, p16-16. 1/3p.
  4. EAST BAY MUNICIPAL UTILITY DISTRICT WATER SYSTEM REVENUE REFUNDING BONDS, SERIES 2012B "Archived copy" (PDF). Archived from the original (PDF) on 2014-11-07. Retrieved 2015-05-15.CS1 maint: discouraged parameter (link) CS1 maint: archived copy as title (link)