Overview
Palo Verde Diversion Dam, located on the Colorado River 9 miles northeast of Blythe, California,is a semipervious barrier of sand, gravel, and rockfill, with a crest width of 20 feet, a length of 1,850 feet which includes the spillway, and a maximum height of 46 feet above the streambed. The embankment, consisting of two zones, contains 157,000 cubic yards of material. Both the upstream and downstream slopes of the embankment are 4:1 from crest elevation to riverbed. The upstream zone consists of sand, gravel, and cobble fill, which is protected with 24 inches of riprap to elevation 20.0 feet. The downstream zone is rockfill taken from structure excavation and quarry. The spillway control structure is founded on rock at the right abutment of the dam. It is a gated structure consisting of three 50-foot bays, separated by two 8-foot-thick intermediate piers. The piers and gravity wall abutments support a bridge structure on which is mounted the hoist for operating the spillway radial gates. The headworks structure is designed to direct 1,800 cubic feet per second from the river into the settling basin of the Palo Verde Irrigation District canal system with diversion water at elevation 283.5 feet. The structure includes four 12- by 8-foot conduit barrels with a downstream transition and training channel.
A control house is located immediately upstream of the headworks. In it are housed the panels for the power distribution and control system, forebay stilling wells and probe units, emergency power units, and recording equipment. Emergency power is supplied by a 30-kilowatt, 230-volt, 3-phase, 60-hertz gas engine generator set for use during failure of the local power supply.
Levee System
The 30-mile levee system is divided into the Lower Arizona Levee, Upper Arizona Levee, and the California Levee. At the request of the Tribal Council of the Colorado River Indian Reservation at Parker, Arizona., the levees were located about 1,300 feet from the river channel so the shoreline would not be encroached upon and would, in the future, be made available for recreation development. The tops of the levees were surfaced with 6 inches of selected gravel to provide a roadway for maintenance purposes and access to various points on the river. The design flood for the levees is 75,000 cubic feet per second. The levees are provided with a 20-foot top, land-side slope of 1.5:1, river-side slope of 2:1, and 4 feet of freeboard. The amount of riprap placed varies within different sections of the levees.
Drain
A 21-mile-long intercepting drain was constructed parallel to and 300 feet from the landward side of the lower levee; the outfall is downstream of the dam. The drain was designed for a capacity of 30 cubic feet per second at the upstream end, increasing to 128 cubic feet per second at the outfall below the dam.
Operating Agencies
The Palo Verde Diversion Dam and diversion works were turned over to the Palo Verde Irrigation District for operation and maintenance on December 17, 1957. Operation and maintenance of the levees and drain were transferred to the Bureau of Indian Affairs on August 20, 1958.
