The East Bay Municipal Utility District (EBMUD) is preparing for a seismic upgrade of Chabot Dam that is planned to take a year to complete, starting in the fall of 2014. The upgrade is in response to a 2005 study predicting that Chabot Dam would suffer settlement of 1.5 to 3.5 feet in the event of a maximum credible earthquake of magnitude 7.25 on the Hayward Fault. This potential for settlement was created in the 1880s when surface fill was added to the bottom of the dam. Since the dam is 23 feet higher than the water level, the settlement would not cause the dam to fail, but would require cleanup of the settled soil.
The report also predicts that the tower would fail, potentially damaging the outlet piping. The pavilion, which covers the tower, is scheduled to be removed as part of the upgrade process.
In order to complete the upgrade, between 6,000 and 12,000 truck trips will be needed to haul dirt to and from Chabot Dam. Although the route of truck traffic has not yet been determined, the trucks could use Estudillo Avenue and the bridge across San Leandro Creek at the end of Estudillo Avenue to haul the dirt. This means that San Leandro's Chabot Park will be closed for an extended period of time and will mean summer day camps will have to be moved. The West Shore Trail between Chabot Park and Lake Chabot will also be closed during construction.
The San Leandro City Council received a presentation on the seismic upgrade at its September 17, 2012, meeting. Similar presentations were made to Friends of San Leandro Creek on September 18 and the San Leandro Disaster Council on October 26.
EBMUD will prepare an Environmental Impact Report (EIR) prior to starting the project and will provide an opportunity for the public to comment on the draft EIR prior to 2014.
Chabot Dam created Lake Chabot, which provides an emergency water supply for EBMUD, in 1875. Water from Lake Chabot also supplies the Lake Chabot and Willow Park golf courses.
EBMUD's project page is available at http://www.ebmud.com/about-ebmud/news/project-updates/chabot-dam-update and a list of frequently asked questions is available at http://www.ebmud.com/our-water/water-supply/current-projects/chabot-dam-upgrade-frequently-asked-questions. For more information, contact Michelle Blackwell at firstname.lastname@example.org.Posted by Mike Katz-Lacabe at November 11, 2012 11:42 AM | TrackBack