The New Waddell Dam holds back a reservoir called Lake Pleasant, which provides storage for water for the Central Arizona Project, an aqueduct system that brings water to Phoenix and Tucson from the Colorado River. At the base of the dam is the New Waddell Pump-Generating Plant, which opened in 1994, and generates a modest 40 megawatts of hydropower for the grid. When reversed, the plant’s four turbines pump water from the aqueduct into the reservoir, helping to regulate its level. The dam was constructed between 1985 and 1994. It replaced the smaller impoundment of the original Waddel Dam, built in 1927, a rare example of a reservoir flooding a reservoir.