A Brief History of the Alpine Dam


IT STARTED WITH a man named Hiram. In 1910, California governor Hiram Johnson signed legislation leading to the formation of municipal water districts throughout the state. Marin County, already in existence for 60 years, was quick to respond.

In 1912, the Marin Municipal Water District (MMWD), serving San Rafael, the Ross Valley and all of southern Marin, became the first municipal water district in the state. And one of MMWD’s first tasks was to build Alpine Dam, which would provide drinking water for the county’s growing population (two dams already existed locally: Lagunitas, built in 1872, and Phoenix Lake, built in 1905).

Alpine Dam was designed in-house with consultation provided by M.M. O’Shaughnessy, the well-known engineer of San Francisco’s Hetch Hetchy water system and at the time an MMWD board member. According to the book Mount Tamalpais and the Marin Municipal Water District, by current MMWD director and historian Jack Gibson, construction on Alpine started in the summer of 1917, but the outbreak of World War I led to shortages of labor and materials for the contractor.

So in January of 1918 MMWD took over the building of Alpine Dam and it was completed a year later. When first built, it held just over a billion gallons of water, but the dam was raised in 1924 and again in 1941 — the structure now has a capacity approaching 3 billion gallons and continues to play a vital role in supplying fresh water to thousands of MMWD customers.

Curious water watchers can actually drive over the scenic dam by taking the Fairfax-Bolinas Road southwest from the town of Fairfax. Fair warning: it’s a long and twisty road and may call for a Dramamine or two.