Situated in southwest Riverside County near the Santa Ana Mountains – about 60 miles southeast of Los Angeles – Lake Mathews is a major reservoir in Southern California. The lake is the terminus of the Colorado River Aqueduct, accepting water that’s traveled 242 miles from Lake Havasu – a reservoir on the Colorado River at the California/Arizona border. It supplies water used by members of the Metropolitan Water District of Southern California.
While still under construction, it was called “Cajalco Reservoir,” allegedly derived from Gabrielino Indian and Spanish words until renamed in 1940 in honor of W.B. Mathews, the attorney who drafted the laws creating both the Hoover Dam and Metropolitan Water District.
The dam that created the reservoir was finished in 1939, and water was first delivered to the public in 1941. Twenty years later, the building of two dikes increased the holding capacity to its current 182,000 acre-feet, raising the water level by 33 feet.
The 13,000 acres surrounding the reservoir is protected land called the Lake Mathews Estelle Mountain Reserve, an important resting area for birds such as ducks, cormorants, grebes, golden eagles and bald eagles.
To protect water quality, Lake Mathews is not open for recreational use.