Eight years into a ten year Seismic Improvement Program, East Bay Municipal Utility District (EBMUD) is ready to tackle protecting a key component of its system, the Claremont Tunnel, which delivers water to over 800,000 customers west of the Oakland/Berkeley hills. In late June, EBMUD released the draft Environmental Impact Report on a proposed bypass for the 75-year-old tunnel, described as the "crown jewel" of the district's seismic retrofit program.
The Claremont Tunnel runs from the Orinda Water Treatment Plant through the hills to EBMUD's Claremont Center near the intersections of Hwy 24 and Hwy 13. It crosses the Hayward Fault on the west side of the hills. Following the 1989 Loma Prieta earthquake, an evaluation of the potential risk to the EBMUD system from a 7.0 quake on the Hayward Fault showed that the Claremont Tunnel could suffer major damage from ground movement along the fault of up to 7.5 feet. The resulting outage could last up to six months and could require severe water rationing for months in areas west of the hills.
The district determined that reinforcing the tunnel with grout, and adding a new 1570-foot bypass for the most vulnerable tunnel section, would be the most effective ways to deal with the risk. Project design is anticipated to be completed by early 2004, and construction would take approximately two years and cost $38 million. A second alternative would be a longer bypass which would cost $71 million and take longer to construct. Meanwhile, another seismic upgrade project which was recently completed, the Southern Loop (see Feb/Mar 2003 issue) is now in place to provide a backup source of water to the southwestern part of the district following an earthquake.
The Environmental Impact Report addresses issues raised by neighbors and the public, including noise and vibration, impacts on wildlife, traffic and visual impacts. Responses are due by August 14, and the EBMUD Board is expected to approve it at its October meeting.
Leslie Stewart
For more information: Charles Hardy, EBMUD, 510-287-0141; Bill Kirkpatrick, EBMUD, 510-287-1301.