O'Shaughnessy and the Dam That Muir Called a Death

Michael Maurice O'Shaughnessy was the city engineer of San Francisco from nineteen twelve to nineteen thirty-two, and the dam that now bears his name in Hetch Hetchy Canyon was the defining project of his career. O'Shaughnessy was an Irish-born engineer who had already built roads and water systems across California and Hawaii before San Francisco hired him, and he brought to Hetch Hetchy a conviction that the project could be done correctly, on time, and within budget. Construction began in nineteen fourteen after years of political fighting.

Workers carved a road through the granite mountains east of Groveland to reach the canyon, crossing terrain that mule teams had barely managed before. The dam itself is a curved concrete arch approximately two hundred twenty-five feet tall, completed in nineteen twenty-three. The dedication ceremony was held on July seventh, nineteen twenty-three, with city officials praising the engineering as a triumph of American capability.

Water from the reservoir reached San Francisco in nineteen thirty-four after the completion of additional tunnels through the Coast Ranges. At the dedication, O'Shaughnessy reportedly acknowledged that the dam had been built over the dead body of John Muir. The Hetch Hetchy fight, though Muir lost it, helped establish the principle that national parks deserve protection from development of any kind, an idea that has shaped every conservation battle in the United States since.