Built in the saddle of two mountains, Diamond Valley LakeSouthern Californias newest and largest reservoiris a vital link in the regional system thats brought water to Southern California for the past 60 years. The lake nearly doubled the areas surface water storage capacity and provided additional water supplies for drought, peak summer and emergency needs.
Water began pouring into the reservoir in November 1999 and the lake was filled by early 2002. Diamond Valley Lake holds 800,000 acre-feet, or 260 billion gallons of water. By comparison, Lake Havasu, on the Colorado River, holds just 648,000 acre-feet or 201 billion gallons.