 The high rockfill dam was built by San Francisco and the Modesto and Turlock Irrigation Districts.The reservoir has a capacity of and is linked to Lake Eleanor via a tunnel, allowing the two reservoirs to essentially operate as one.It provides drinking water and flood control for communities in the Central Valley, and generates hydroelectricity at the Dion R. Holm Powerhouse (originally named Cherry Powerhouse), which began operation on August 1, 1960, superseding the Early Intake Powerhouses.