San Diego County Dams Old But Still Passing Muster
Monday, May 16, 2016
While San Diego's aging dams have passed their latest inspections, government agencies make little information public about the threat a failure would pose.
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San Diego County has 54 dams, and the state judges them all to be safe, an impressive feat considering that the average dam is 62 years old.
inewsource filed Public Records Act requests with the California Division of Safety of Dams and 19 dam-owning public agencies, such as water districts, requesting the latest inspection reports and emergency action plans, if one existed.
According to the reports, all 54 dams were “judged safe for continued use.”
The county’s oldest is Helix Water District’s Lake Cuyamaca dam, an earthen structure constructed in 1887.
The inspections can turn up crucial early warning signs of problems that, if left unchecked, could lead to a dam’s failure.
Mark Ogden, a project manager at the Association of State Dam Safety Officials, a national nonprofit organization, said that dam failures are a fairly regular occurrence.
“I think it probably happens more frequently than most people think,” said Ogden, pointing to the failure of more than a dozen South Carolina dams during severe flooding last October.
In most cases, state data suggest a dam failure around here wouldn’t be catastrophic.
But 20 San Diego County dams were considered high hazard in 2002, meaning failure would likely result in the loss of human life. They include the dams at Lake Hodges and the San Vicente Reservoir.
Dams in San Diego County
We don’t have more updated information because the California Division of Safety of Dams and the U.S. Army Corps of Engineers have refused to release updated data on dams’ hazard rating since 2002, citing concerns about terrorism.
Since then, several dams have been built or upgraded in the county. And some dams not rated as high hazard at the time may have moved into the high hazard category as a result of development in unincorporated parts of the county.
While declining to offer an opinion on whether information about a dam’s hazard rating should be made available to the general public, Ogden said his organization strongly believes that people who are most threatened should know their risk, and it offers publications to help them make that assessment.
“Somebody who lives in an area of a dam should be able to get information about whether or not they’re in an inundation (flood) zone,” Ogden said.
Should a dam fail, emergency management officials might look to an emergency action plan, which spells out escalating steps to be taken, culminating in an evacuation.
Among 41 publicly owned dams, 34 had emergency action plans and seven did not as of earlier this year.
Of the seven that didn’t, two were considered high hazard as of 2002.
Despite the low ranking for the state’s water infrastructure as a whole, Ogden called California’s dam safety program “a model for all the states” and praised the resources the state dedicated to inspecting dams.
That’s in part, he said, because the cost of a dam’s failure could be so high.
“Part of that is a reflection of the types of dams in California and the fact that so many people live downstream of these dams,” Ogden said. “The magnitude of the problem if there were to be a problem is much higher than other areas.”
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