The U.S. Geological Survey recently released a Hayward Earthquake Scenario that reminds Bay Area residents and businesses to prepare for “the big one” and stresses the need for improving local infrastructure to protect San Francisco Bay Area water supplies in the event of a 7.0-magnitude earthquake on the Hayward Fault. CA WaterFix proponents are touting the report as a justification for building the tunnels as an upgrade to the current infrastructure system, but this exaggerates the report’s findings, which only mentions Delta levees being “affected” by aftershocks in the Survey’s modeled scenarios of the large earthquake.
Other research by seismologists and geologists indicate that quakes originating on Bay Area earthquake faults, such as the August 2014 Napa quake, had little impact on Delta levees because the regional geology reduces or “attenuates” the shaking effects before they reach the Delta area. The “HayWired” report was focused entirely on effects of a major quake within the Bay Area, and especially the East Bay corridor west of the Hayward Fault, which his served by East Bay Municipal Utilities District.
Executive director of Restore the Delta, Barbara Barrigan-Parrilla said,
“The Hayward Earthquake Scenario Report recently released by the USGS discusses interruption of water supply to the San Francisco Bay Area as a result of a 7.0 Earthquake on the Hayward Fault. It should be noted that the report’s findings agree with the Delta Risk Management Study conducted several years back by the California Department of Water Resources that water supply from the Delta could be restored fully within six months of a major quake on the Hayward Fault and that water supply is not fully disrupted.
“What the public needs to understand is that the Brown Administration’s cure for this challenge, the Delta tunnels, are not being designed to meet seismic safety standards. The WaterFix tunnels are not currently being designed to withstand a maximum Considered Earthquake on nearby faults, as defined by the American Society of Civil Engineers’ ASCE-7 standard. To read more on this design inadequacy click here.
“We cannot help questioning if the cure could be worse than the status quo. If tunnels collapse underground from a seismic event, they could be much harder to repair, the environmental damage for the Delta could be more significant, and the repairs could cost more than repairs for above ground levees. These are questions that must be asked and answered by project proponents.”
Policy Analyst for Restore the Delta, Tim Stroshane, said,
“The purpose of the HayWired study is to urgently remind Bay Area residents to be prepared for a large earthquake. Its scope does not extend this level of warning to the Delta region and indicates only that there could be some shaking effects that could affect Delta levees. The point of the report is to get ready—and that means investment in local infrastructure to ensure survival and resilience is where public investments should be made. The report in no way is a call to construct and operate California WaterFix.”