Friant Dam - Construction

Construction

Construction of Friant Dam began with blasting and excavation of the dam site to remove more than 1,200,000 cubic yards (920,000 m3) of loose material above the bedrock. Before any concrete was laid on the dam's main wall, the underlying rock was extensively grouted to fill in 725 holes and seams that might otherwise cause instability in the foundation. The concrete used in the dam's construction was made from sand and gravel excavated from the San Joaquin River floodplain about 3 miles (4.8 km) below the dam. Notably, more than 5,400 ounces (150 kg) of placer gold – worth $176,000 at the time – was uncovered in the excavation site. A branch line of the Southern Pacific Railroad delivered this material to a concrete mixing plant, which could produce up to 6,000 cubic yards (4,600 m3) of concrete per hour, directly adjacent to the construction site. In July 1940, the San Joaquin River was diverted through a wooden flume so that work on the foundations could begin.

On July 29, the first concrete was poured into the main body of Friant Dam. In order to keep the structure in line, the dam was built in a series of blocks or forms, each measuring 50 feet (15 m) square. Concrete was placed via a massive steel trestle system 210 feet (64 m) high and 2,200 feet (670 m) long, along which ran small powered railcars that delivered buckets of concrete from the mixing plant. Two gantry cranes lifted the buckets from the cars and poured them onto the forms. In summer 1941, the labor force reached a peak of 1,500, and the monthly record for concrete placement, at 228,000 cubic yards (174,000 m3), was set in August. The workforce scrambled to complete the main wall of the dam after an act of the War Production Board (WPB) suspended resources in order to assist U.S. military efforts in World War II. The dam was topped out on June 16, 1942, just under two years after the first concrete was poured. However, the spillway gates, the water release valves and the two irrigation canals Friant was intended to support remained unfinished in the wake of the WPB's order.

The war, however, did not completely halt construction. Less than a year later, the WPB " the completion of the Madera Canal and the installation of valves at the Friant Dam, necessary for war-time food and fiber production" – allowing construction to resume on a limited scale. A pair of control valves were borrowed from Hoover Dam, allowing the closure of the river outlets and Millerton Lake began to fill on February 21, 1944. Work on the Madera Canal, the smaller of the two irrigation canals serviced by Friant Dam (the other, the Friant-Kern Canal, would not be completed for another four years), was completed in 1945 and water ran for its entire length for the first time on June 10, with irrigation deliveries commencing one month later.

The dam was formally dedicated on July 9, 1949 by California governor Earl Warren, who declared that the water furnished by Friant Dam and its canals would help the San Joaquin Valley to "become a modern Eden" as water was released into the partially completed Friant-Kern Canal for the first time. More than three thousand people, mostly residents of the San Joaquin Valley, attended the ceremonies.

" but a lifeline to preserve and enhance our American civilization. This is a line of creation, built to unlock the fertility of the rich soil, to resist drought, to overcome floods, to provide outdoor recreation, and to generate cheap power that will improve the living conditions of millions of our citizens."
– Harold Ickes, Secretary of the Interior, at Friant Dam dedication