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Calaveras Reservoir[1]
Location Santa Clara / Alameda counties, California, US
Coordinates 37°28′43″N 121°49′21″W / 37.4785°N 121.8226°W / 37.4785; -121.8226Coordinates: 37°28′43″N 121°49′21″W / 37.4785°N 121.8226°W / 37.4785; -121.8226
Type Reservoir
Primary inflows Arroyo Hondo
Calaveras Creek
Catchment area 98.4 sq mi (255 km2)
Basin countries United States
Built 1925
Surface area 1,450 acres (590 ha)
Water volume 100,000 acre·ft (120,000,000 m3)
Surface elevation 781 feet (238 m)
References [2]

Calaveras Reservoir is located primarily in Santa Clara County, California, with a small portion and its dam in Alameda County, California. The reservoir has a capacity of 100,000 acre·ft (120,000,000 m3). In Spanish, Calaveras means "skulls".

Calaveras Reservoir is fed mainly by Arroyo Hondo and Calaveras Creek. Lying in the Calaveras Valley, the region is a geologically active area with the Calaveras Fault parallel to, and to the west of, the dam site. Because of the hazard, a replacement dam is scheduled to open in 2018. Roads adjacent to the reservoir include Calaveras Road and Marsh Road. The latter drew significant attention from a murder there in the early 1980s.

Poverty Ridge and Oak Ridge lie to the east of Calaveras Reservoir, Milpitas and Monument Peak lie to the west, Sunol lies to the far north, and Calaveras Creek and Los Buellis Hills lie to the south.

The Calaveras Valley is rich and diverse in wildlife. Some of the most common animals include deer, coyotes, squirrels, turkey vultures, red-winged blackbirds, yellow-billed magpies, red-tailed hawks, brewer's blackbirds, purple martins, barn swallows, bullock's orioles, and warblers. Since at least 2008 there has also been a regular nesting pair of bald eagles.[3]

Calaveras Reservoir in Spring 2006


In the 19th century, the Calaveras Valley which the reservoir now fills was primarily an agricultural region known for its production of hay, strawberries, and tomatoes. Because of San Francisco's increasing demand for drinking water at the turn of the 20th century, the farmers in the region were forced to sell their land to the Spring Valley Water Company, which in turn sold it to the San Francisco Water Company.

The first dam on the site, built in 1913 by the Spring Valley Water Company, rapidly changed the sensitive hydrology and natural environment of the Calaveras Valley. It suffered a partial collapse of the upstream slope in 1918 due to engineering flaws. Its replacement, the current Calaveras Dam, was at its completion in 1925 the largest earth-fill dam in the world. It is 245 feet high, with a length of 1200 feet at its crest.[4] The city and county of San Francisco owns and operates the dam and reservoir for municipal water supply.

Livestock along Calaveras Road, May 2006

The reservoir is reported to contain a very large population of largemouth bass, rainbow trout and other species. However, fishing is prohibited.

Today, the San Francisco Public Utilities Commission (SFPUC) owns 36,000 acres (150 km²) in the Alameda Creek Watershed. Some lands in the watershed are leased to livestock companies for cattle ranching to control vegetation and prevent fires. Most of the land is closed to the public because of concerns over drinking water safety and quality.

Dam replacement[edit]

Because the dam is located near a seismically active fault zone and was determined to be seismically vulnerable, in 2001 the California Department of Water Resources, Division of Safety of Dams (DSOD) has restricted the reservoir to approximately 30 percent of its original capacity, 96,850 acre feet (119,460,000 m3), until the deficiencies are corrected.

The San Francisco Public Utilities Commission is constructing a new dam of equal height downstream of the existing dam as part of the $4.3 billion Water System Improvement Program. The 7 year-long environmental impact study report was certified by the San Francisco City Planning Commission on January 27, 2011. Later that day, the $434 Million Calaveras Dam Replacement Project was given the green light by the SFPUC.[5] Excavation began in 2011 with construction on the actual dam expected to begin in 2016. The entire replacement should be complete in 2018.[6]

The replacement effort will include several measures to aid in the restoration of native fish populations. However, construction of a fish ladder to provide Steelhead trout (Oncorhynchus mykiss) access to the waters above the dam was deemed infeasible because at 290 feet (88 m), it would be the tallest fish ladder in the country and cost $40 million. Steelhead trout have not had access to spawning streams above Calaveras Dam since 1925.[7] However, environmentalists won concessions from the SFPUC to assure adequate water releases from the new dam to improve summer flows as well as a smaller fish ladder around a diversion dam blocking access to upper Alameda Creek, which is regarded as prime trout habitat.[8]

Aerial view of Calaveras Reservoir showing the reconstruction of the dam wall

Plane crash discovery[edit]

In the late 1980s and early 1990s, a drought affected California, and water levels in reservoirs throughout the state became extraordinarily low. By January 1991, the water at the reservoir was down 100 feet (30 m), and the aluminum body of an airplane became visible. Two skeletons were found at the site on January 5, 1991. Dental records and the plane's serial number were used to positively identify the remains as Clifford Gillman and his single-engine Ercoupe, along with Gillman's friend Robert Louviere. They had been missing since June 16, 1963. The wreck, minus the two men's bodies, is still lying in the center of the reservoir.[9]

See also[edit]


  • Loomis, Patricia. Milpitas: A Century of Little Cornfields

External links[edit]

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Calaveras_Reservoir — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.

162 news items

San Jose Mercury News

San Jose Mercury News
Tue, 19 Apr 2016 00:29:40 -0700

Tucked away in the remote hillsides east of Interstate 680, Calaveras Reservoir is the largest reservoir for the Hetch Hetchy system in the Bay Area, a key part of providing water to 2.6 million customers in Alameda, Santa Clara, San Mateo and San ...


Fri, 29 Apr 2016 14:47:17 -0700

The Hayward and Calaveras Faults may have a simpler connection at depths more than 5 km (3 miles), joining in the subsurface just south of the Calaveras Reservoir (site of the October 30, 2007 M5.4 Alum Rock earthquake). The Hayward Fault may be ...


Wed, 20 Apr 2016 15:35:17 -0700

"The goal is to return the Calaveras Reservoir to its historic capacity of 31 billion gallons. In 2001 we lowered the levels of Calaveras Reservoir to 40% out of seismic safety concerns for the existing 91-year-old dam," said Rhodes. "Restoring it to ...

CBS Local

CBS Local
Tue, 19 Apr 2016 20:56:15 -0700

KPIX 5 | CBS San FranciscoConnect With Us At KPIX 5 PROGRAM GUIDE: KPIX 5 TV Schedule WATCH: A Glimpse Inside The Working KPIX 5 Newsroom Breaking News Send news tips, video & photos, and video to the KPIX 5 [...] KCBS[1]. CONNECT WITH ...


Thu, 26 Nov 2015 05:52:30 -0800

The Calaveras Reservoir, which is the largest of the system's five local reservoirs, is also in need of a seismic makeover. Its 90-year-old earth and rock-filled dam, which forms the reservoir, is located on the Santa Clara-Alameda county line, and is ...


Thu, 25 Apr 2013 17:28:50 -0700

The Calaveras Reservoir dam, east of Milpitas, is a massive earthen structure built across Calaveras Creek in 1925. These traditional dam designs are generally robust—the Crystal Springs Reservoir on the Peninsula has one that easily weathered the ...

Tech Times

Tech Times
Wed, 09 Jul 2014 07:43:22 -0700

Workers at the construction site of a new dam stumbled upon a treasure trove of fossils in the Calaveras Reservoir. (Photo : Christian Ey). The Calaveras Reservoir east of Milpitas, California, is set to become home to a new dam project. But workers ...


San Jose Mercury News
Sun, 06 Jul 2014 16:08:02 -0700

Walker and construction crews building a new 220-foot-high dam at Calaveras Reservoir in the remote canyons east of Milpitas have been digging up a prehistoric treasure trove: the teeth of an extinct hippopotamus-like creature called a Desmostylus ...

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