Michael O’Shaughnessy and the Hetch Hetchy Project

Michael Maurice O’Shaughnessy (May 28, 1864–October 12, 1934) was an Irish civil engineer who worked on two railroads near San Francisco, laying out the towns of Mill Valley and Sausalito. O’Shaughnessy started a San Francisco office for an International Exposition, designed the Copper Mountain Company railroad, and worked for Spring Valley Water (San Mateo) and water projects in Hawaii in 1889, including four aqueducts. Michael then worked on Morena Dam outside San Diego and on the Merced River Dam as well as a water supply for Port Costa. O’Shaughnessy became city engineer for the city of San Francisco, supervised the construction of the Twin Peaks Reservoir, Twin Peaks and Stockton Tunnels, the Municipal Railway System-completing the San Francisco streetcar system, street planning, a high-pressure fire system and new sewers. Additionally, the prominent U.S. hydraulic engineer O’Shaughnessy started the Hetch Hetchy Dam (renamed O’Shaughnessy Dam on July 7, 1923), 150 miles of tunnels, pumping stations, hydroelectricity, a 68-mile-long railroad, several smaller dams, and 156 miles of aqueduct and pipelines to San Francisco. Water diverted from O’Shaughnessy Dam flows by gravity into the Hetch Hetchy Aqueduct, which supplies 85 percent of the municipal water for 2.5 million people in the San Francisco Bay Area.