Whittier Narrows Dam

About

Whittier Narrows Dam is a 56-foot (17 m) tall earth dam on the San Gabriel River and the smaller, parallel Rio Hondo. The dam is located, as the name implies, at the Whittier Narrows. It provides water conservation storage and is also the central element of the Los Angeles County Drainage Area (LACDA) flood control system. Its reservoir has a capacity of 67,060 acre⋅ft (82,720,000 m3).

The Whittier Narrows are a natural gap in the hills that form the southern boundary of the San Gabriel Valley of Southern California. Both the Rio Hondo, a tributary of the Los Angeles River, and the San Gabriel River flow through this gap and are impounded by the reservoir. The Pomona Freeway (CA-60) passes through the reservoir flood control basin and the San Gabriel River Freeway (I-605) passes along the eastern boundary of the basin.