Reservoirs

Water Storage Overview

24 Reservoirs Store Local and Imported Supplies

The San Diego region has 24 reservoirs with a combined capacity of about 721,000 acre-feet of storage. Several of these reservoirs receive runoff from major stream systems that originate in the mountains of San Diego County and drain into the Pacific Ocean.

In addition, San Diego County ratepayers have invested in reservoirs owned by the Metropolitan Water District of Southern California, and the Water Authority is seeking a storage account in Lake Mead that would benefit the San Diego region and the Colorado River Basin.

The last major increase in San Diego regional water storage capacity occurred in 2014 when the San Vicente Dam Raise was completed, adding 157,000 acre-feet of capacity. While the region’s reservoirs were built mainly as water supply projects, they also provide other benefits such as recreation, flood reduction and hydroelectric generation.

Each reservoir has unique characteristics that define its role in meeting the region’s water supply needs. Some reservoirs are important from a regional water reliability standpoint, while others are primarily used by local agencies for operational flexibility.

Since the major statewide drought of 1976-1977, annual surface water use from local reservoirs has ranged from 4,100 acre-feet in fiscal year 2015 to 140,300 acre-feet in fiscal year 1984. Over the past 10 years, an average of about 6 percent of the region’s total annual water supply came from local surface water.