Claremont Water Tunnel (EBMUD) (Oakland, California)

 tunnel, water pipeline

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The Claremont tunnel beneath the Berkeley Hills on the east side of Oakland is a water supply tunnel that serves over 800,000 customers in Richmond, Oakland, San Leandro and neighboring communities. One of the unique things about the tunnel is that it crosses the active Hayward Fault. Most of the time when you talk about designing for earthquakes you’re talking about designing to withstand the seismic forces. In this case, the designers needed the water transmission tunnel to withstand up to 7.5-ft of offset due to fault slip and still maintain a minimum level of service.

Owned by the East Bay Municipal Utility District (EBMUD), the original tunnel was 3.4 miles long and 9-ft by 9-ft and was completed in 1929. At the time, no special design considerations were made for the fault. A nominal 1-ft thick concrete lining was used, and little of that was reinforced. Only a small portion of the final tunnel was contact grouted to fill in the voids between the lining and surrounding ground.