Don Pedro Reservoir

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Don Pedro Reservoir
Tuolumne river-south fork 3.jpeg
Location Stanislaus National Forest
Tuolumne County, California
Coordinates 37°44′29″N 120°22′25″W / 37.7415°N 120.3735°W / 37.7415; -120.3735Coordinates: 37°44′29″N 120°22′25″W / 37.7415°N 120.3735°W / 37.7415; -120.3735
Type Reservoir
Primary inflows Tuolumne River
Primary outflows Tuolumne River
Catchment area 1,500 sq mi (3,900 km2)
Basin countries United States
Surface area 13,000 acres (5,300 ha)
Water volume 2,030,000 acre·ft (2.50 km3)
Shore length1 160 mi (260 km)
Surface elevation 245 m (804 ft)
Islands Laughlin Ridge
References U.S. Geological Survey Geographic Names Information System:
1 Shore length is not a well-defined measure.

Don Pedro Reservoir is an artificial lake formed by the construction of the New Don Pedro Dam across the Tuolumne River in the Stanislaus National Forest of Tuolumne County, California in the foothills of the Sierra Nevada. Communities located nearby are Moccasin and La Grange.

Also referenced as Don Pedro Lake when the name is qualified, the first projects in 1923 are generally referred to as the Old Don Pedro Dam and reservoir, and the 1971 upgrades are the New Don Pedro Dam and reservoir. Don Pedro Reservoir takes its name from Don Pedros Bar.[1] Pierre ("Don Pedro") Sainsevain was one of the first prospectors after the discovery of gold in 1848.


Overhead of Don Pedro Reservoir (bottom right) upstream of irrigated land in the Central Valley.

When full, the reservoir's shoreline is approximately 160 mi (260 km). The reservoir submerges some 26 mi (42 km) of Tuolumne River bed, and has a surface area of about 13,000 acres (5,300 ha). The 2,030,000 acre·ft (2.50 km3) stored here comes from a watershed of over 1,500 sq mi (3,900 km2), and is used by the Modesto Irrigation District (MID) and the Turlock Irrigation District (TID) for the irrigation of several hundred square miles of Central Valley farm land. Some of the water is treated by the MID and used as drinking water in Modesto. The two irrigation districts and the BLM control the land 15 feet (4.6 m) above the high lake level, so there are no private boat docks on lakefront parcels. There are three public boat ramps.

It is the sixth-largest artificial lake in California.

Hetch Hetchy project[edit]

While Lake Don Pedro is not part of the Hetch Hetchy Aqueduct, its tunnels cross under the upper end of the reservoir. Lake Don Pedro could easily be tied into that system in the future, and the efforts of the Restore Hetch Hetchy group to drain the reservoir in the Hetch Hetchy Valley depend largely on that possibility. The San Francisco Public Utilities Commission (SFPUC), of which Hetch Hetchy Water and Power is a division, provided about 45% of the funds for construction of the 1971 New Don Pedro Dam and so has the right to store 570,000 acre feet (700,000,000 m3) of water in the reservoir. Each year, San Francisco takes about 230,000 acre feet (280,000,000 m3). The rights of the MID and the TID are senior to those of SFPUC, however, so in dry years MID and TID can draw down the reservoir to meet their own needs before providing water to San Francisco's Hetch Hetchy Water and Power.


See also[edit]


  1. ^ Who was Don Pedro? Don Pedro Recreation Agency

External links[edit]