These before and after images show water levels in California's Folsom lake during a wet period (July, 2011) and the current drought (January, 2014). Folsom Lake is a reservoir in north-central California near Sacramento. The lake is formed by Folsom Dam, constructed in 1955 to control the American River. The dam and lake are part of the Folsom Project, itself part of the larger Central Valley Project. The dam was designed to hold 1,010,000 acre feet of water with a surface area of 11,450 acres.