Stone Canyon Reservoir, reservoir in Bel Air, Los Angeles, United States

Stone Canyon Reservoir is the larger of two adjoining reservoirs in the Bel Air neighbourhood of Los Angeles, in the Santa Monica Mountains south of Mulholland Drive. Its earth-fill dam, 160 feet high, holds an irregular lake with a 5,500-foot shoreline and 117 acres of surface. The smaller, cone-shaped Upper Stone Canyon Reservoir lies just to the north.

The lower reservoir was designed and built in 1924 by the Bureau of Water Works and Supply, using earth fill placed by hydraulic sluicing, a method refined by William Mulholland; its original capacity was 8,000 acre-feet. In the mid-1950s the upstream part of the 160-foot dam was rebuilt as roller-compacted backfill founded on rock, finished in 1956. Seismic studies in 2002 found the Lower Stone Canyon Dam could be operated safely at its design elevation of 865 feet.

The reservoirs are owned by the Los Angeles Department of Water and Power and are working water-supply facilities, not a public recreation area; the sources describe no shoreline trails. The Lower Stone Canyon Dam stands 160 feet (49 m) high, and a security fence surrounds the membrane filtration plant below it. The reservoirs sit south of Mulholland Drive and west of North Beverly Glen Boulevard in Bel Air.

The Lower Stone Canyon Dam stands 160 feet high; its upstream section was rebuilt in the mid-1950s as roller-compacted backfill founded on rock, while the downstream part kept its 1924 earth-fill form. A 2002 seismic study concluded the dam could operate safely with the reservoir at its design elevation of 865 feet.