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After a quake, what will happen to the Bay Area’s water supply?

on May 16, 2011

What would happen to the water supply if a major earthquake struck the Bay Area? According to the East Bay Municipal Utility District (EBMUD), which supplies water to most of the East Bay, there is a 32 percent chance of a magnitude 7 earthquake occurring along the Hayward Fault in the next 30 years. In a worst-case scenario, the Claremont Tunnel, which runs directly through the Hayward Fault and provides water for 800,000 of EBMUD’s customers, would be out of commission for six months.

“They don’t really know exactly how [the pipes crossing the Hayward fault] would behave in a major earthquake,” said Matthew Heberger, a Research Associate at the Oakland-based Pacific Institute, but waste management plants and deteriorating sewage lines would likely be damaged and could create a back-flow of raw sewage, which would escape through manholes and flow onto surface streets.

The East Bay’s sewage lines “are fairly old, and some of them have areas of wear and cracking and corrosion,” said Tim Pine, a member of the Office of Environment, Health and Safety at UC Berkeley and a former employee at EBMUD. “It’s a possibility that we’d have some sewer lateral collapses.”

EBMUD has been working hard — and spending a lot of money — to make sure that water will keep flowing in the event of an earthquake. In the aftermath of the Loma Prieta earthquake in 1989, the EBMUD Board of Directors approved the 10-year, $189 million Seismic Improvement Program (SIP) in 1994. This undertaking, which was, according to Pine, funded by a surcharge on water bills, has addressed the most at-risk areas. These include the draining, inspection and repair of the Claremont Tunnel; and the construction of the 11-mile-long Southern Loop Pipeline, which allows EBMUD to route water south, around the Berkeley hills and up from San Leandro, during an emergency.

If a major earthquake was to strike the Bay Area, EBMUD would not be in charge of the emergency response, said Charles Hardy, spokesman for EBMUD. Contra Costa and Alameda Counties’ emergency services offices would take command. Nevertheless, EBMUD has implemented other improvements to make an emergency response easier to implement. According to Pine and Hardy, EBMUD has large spools of flexible water pipes that can be towed out and used to bypass broken water lines, as well as mobile, high-power pumps to maintain the water pressure.

Although the Seismic Improvement Program officially ended in 2005, the process of retrofitting and improving infrastructure has been ongoing. “We found that it doesn’t stop,” said Hardy. “It’s a continuous process.”

One of the larger projects that EBMUD is currently undertaking, according to Hardy, involves updating its “interceptors,” large, horseshoe-shaped sewage tunnels that run parallel to the bay and collect waste water. Such upgrades don’t just patch damage, said Hardy. Rather, the new pipes are designed to move with the earth during a quake, so they won’t collapse.

After the Loma Prieta earthquake and, particularly, the 1994 Northridge earthquake—which caused $400 million of damage to the Cal State University at Northridge—Bay Area colleges began making detailed emergency plans to support their large student populations. “[UC Berkeley] takes on a fair amount of responsibility for the students’ safety and well being,” said Pine. “There’s a lot of collaboration between [UC Berkeley] and other universities in terms of planning, experience, what works, what doesn’t.”

At UC Berkeley, in the event of a large quake, emergency responders would report to the Hazardous Materials Facility, a heavily-reinforced building on the west side of campus, and begin to implement water-distribution plans. “Our plan calls for rendering aid to the wider community of Berkeley,” said Pine. “Because we have the largest kitchens, we’re used to serving lots of people.” If worst came to worst, UC Berkeley could tap a well at Strawberry Creek, add chlorine, and distribute supplies at water-distribution centers on campus.

Throughout the entire East Bay, residents would be urged to cut their water use dramatically. “Immediately what there would be is emergency rationing,” said Heberger. “There would be calls going out on radio and TV saying, ‘No water for nonessential purposes.’”

However, said Pine, it is unlikely that there would be a total loss of the water supply during a major earthquake. “That would be a worst, worst case scenario where the water delivery from EBMUD went dry,” he said. “And by all accounts, that’s pretty unlikely.”

Text by Max Siegel

Check out Oakland North’s previous article on earthquake readiness and the risk to local buildings: Is Oakland ready for its next big earthquake?


  1. […] You can read out story about what might happen to the Bay Area’s water supply after a big earthquake by clicking here. […]

  2. […] After a quake, what will happen to the Bay Area’s water supply? Reporter Max Siegel finds out whether we’ll still have water service after a big quake. […]

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