St. Francis Dam - Construction and Modification

Construction and Modification

Construction began without the usual fanfare for a municipal project of this nature. The Los Angeles Aqueduct had become the target of frequent sabotage by angry farmers and landowners in the Owens Valley and the city was eager to avoid any repeat of these expensive and time-consuming repairs. By June of 1923 the studies and surveys for the St. Francis reservoir had been completed. At the time the reservoir as planned was to have a capacity of 30,000 acre·ft (37,000,000 m3) and called for a dam to be built to the elevation of 1,825 feet (556 m) above sea level, 175 feet (53 m) above the stream bed.

In his July 1, 1924, report to the Board of Public Service Commissioners Mulholland gave the capacity of the reservoir as 32,000 acre-feet (39,000,000 m3). On the same day Office Engineer W. Hurlbut informed Mulholland that all of the preliminary work on the dam had been completed. Construction of the dam itself began 5 weeks later when in early August the first concrete was poured.

In March of 1925, prior to Mulholland's yearly report to the Board of Public Service Commissioners, Hurlbut again reported to Mulholland on the progress of the St. Francis dam and reservoir. He stated the reservoir would have a capacity of 38,000 acre-feet (47,000,000 m3) and that the dam's height would be 185 feet (56 m) above stream bed level. Hulbert wrote in his explanation of changes presented to the Board of Public Service Commissioners that "Additional surveys and changes in the plans have disclosed that at crest elevation of 1835 feet above sea level the reservoir will have a capacity of 38,000 acre-feet."

The 10-foot (3.0 m) increase in the dams height over the original plan of 1923 necessitated the construction of a 588-foot (179 m) long wing dike along the top of the ridge adjacent to the western abutment in order to contain the enlarged reservoir.