In 1895, W. H. Beardsley assumed control of the Agua Fria Water and Land Company and started building the Lower Lake Diversionary Dam. After many lengthy delays the Dam was completed in 1927. It stood 84 feet above the river and stretched 600 feet in length. The “Carl” Pleasant Dam, later renamed the Waddell Dam, was constructed between 1926 and 1928 creating the upper portion of the Lake. At this time it was the largest Agricultural Dam in the world. The Dam stood 76 feet in height and 2,160 feet in length. At 126 feet above streambed its elevation was 1,601 feet. It created a lake with a surface size of 3,706 acres of water and a shoreline of 50 plus miles. Lake Pleasant Regional Park, Maricopa County Parks and Recreation Department’s only water-based Park, was formed in 1965. The park, including the Lake, consisted of 14,000 total acres.
The New Waddell Dam was built by the Bureau of Reclamation and was completed in 1993, increasing the surface area of the Lake to 10,000 acres. The Regional Park was increased to approximately 23,662 acres.
The Central Arizona Water Conservation District determines the water level of the Lake. The Lake receives most of its water from the CAP canal as well as from the Agua Fria River. High water elevation is reached in mid spring which brings the water elevation to 1,702 feet above sea level. In June, the draw down cycle begins with water released from the Lake through the CAP canal for irrigation of the west valley, agricultural areas and several cities and towns as far away as Tucson. In 1992, Maricopa County Parks and Recreation Department entered into a fifty year agreement with the Bureau of Reclamation to manage and operate Lake Pleasant Regional Park.