Michael "Chief" O'Shaughnessy, B.E. (1864-1934)

Michael O'Shaughnessy graduated in Civil Engineering from Queen's College Galway in 1884 and for a long number of years was Chief Engineer of the City of San Francisco, undertaking the building of new infrastructures for the city after the disastrous earthquake and fires of 1906.
These works included the construction of the Twin Peaks tunnel, the famous Seashore Wall, the Streetcar (tramway) system and, greatest of all, the San Francisco Water-Supply and Electric-Power project, involving dams, powerhouses and 160 miles of transmission towers, pipelines and tunnels the whole way to the City from the O'Shaughnessy Dam (named in his honour) in the Sierra Nevada (Yosemite National Park), an area generally under snow and ice for most of the winter.

The Hetch-Hetchy project, as it is sometimes called, is numbered among the great engineering projects of the twentieth century. As City Engineer, O'Shaughnessy was also closely involved in the long-running controversy surrounding the proposal to build the Golden Gate Bridge. He died aged 70 in 1934 just a few days before the celebrations which had been planned to honour him following the arrival in the City of the first water from the great Dam, and four years before the Bridge, the construction of which was already well under way, was opened to traffic.

"Chief" O'Shaughnessy was appointed City Engineer of San Francisco in 1912 and he held this office until his retirement in 1932, after which he became Consulting Engineer to the City's Public Utilities Commission. Among the many difficult tasks which he had to perform was to convince the U. S. Congress to grant the necessary permissions for the enormous Hetch Hetchy Power & Water Supply Scheme; he spent many weeks in Washington actively lobbying for support and being examined by members of the Senate.

During one particular week he was examined continuously from Monday morning until late on Saturday evening. In spite of strenuous opposition, largely from vested interests, he eventually secured the necessary approvals, which were signed by President Wilson in 1913. In his own words "I never handled any proposition where the engineering problems were so simple and the political ones so complex". He was, of course, being his usual modest self about his Engineering skills!

Even to the layman, the site chosen for the dam must appear ideal for its purpose. In addition to the splendid topography of the valley, the fact that the mountains are largely granite made this location unbeatable in spite of its distance, 160 miles, from San Francisco. The area of the watershed contributing to the reservoir behind the O'Shaughnessy Dam is roughly 460 sq. miles (1, 150 sq. km.); the total watershed for the entire project exceeds 650 sq. miles. (1,620 sq.km)

In 1912, at the beginning of the Hetch Hetchy Project, there were few roads and no motorcars in the High Sierras. The building of a mountain railway, the Hetch Hetchy Rail Road (H.H.R.R.) was the first task 0' Shaughnessy set himself. All the materials for its construction came by mule trains like the one shown here. There were long rail tunnels, and many bridges, to be built before any thought could be given to starting the construction of the permanent Works, namely, the Dams, the Power-plants and the aquaduct itself.

O'Shaughnessy was not, of course, picked out of no-where to take over as Chief Engineer of San Francisco; his earlier career made him the obvious choice. Among his earlier employments were:

  • Engineer with the Southern Pacific Railroad and with the Sierra Valley and Mohawk Railroad
  • Chief Engineer of the Mountain Copper Company where he built 12 miles of narrow gauge mountain railroad
  • He spent some time in Hawaii building an aggregate of about thirty miles of large irrigation conduit and some twenty miles of tunnel
  • He constructed the 260 ft high Morena Dam and 13 miles of conduit with seventeen tunnels for the City of San Diego

He had all the necessary experience in building dams, tunnels, conduits and railroads which were the essential parts of the great Hetch Hetchy Scheme and he had no trouble turning his mind to the design of sea-defence works, tramway systems and other urban design projects in San Francisco.





Michael O'Shaugnessy with his family on the steps of their unpretentious house, his wife, Mary, stands behind Michael. Also included is their son John, who died young, and their four daughters. Three of their daughters then surviving, Mary, Helen, and Elizabeth, visited Prof. Declan O'Keeffe in the Engineering School in Galway in the sixties and thus started a correspondence which he maintained with them until the last daughter, Elizabeth, died in 1998.

In 1923, nine years after it's construction had begun, the dam was first brought into service. It was later raised to a greater height to increase the capacity of the reservoir.This additional work had, of course, been part of the original design. The need for adequate water supply has plagued most of California in recent years, but water is no problem for San Francisco, thanks to the foresight of Michael O'Shaughnessy.

The splendid topography of the valley made this location for the dam unbeatable, in spite of it's location in unmapped wilderness 160 miles from San Francisco.

All of the construction materials for the temporary mountain railway, the Hetch Hetchy Rail Road, including those for the many tunnels, were brought by mule trains like this one.