Decades-Long Quake Retrofit Of Flood Control Dams Nears Completion

LOS ANGELES (CBSLA.com) — Engineers are nearing completion on a project to retrofit all 14 flood control dams in Los Angeles County to be able to withstand a major earthquake, officials said Tuesday.

The County Department of Public Works began the effort following both the 1971 Sylmar quake and the 1994 Northridge earthquake, which caused officials to undertake a nearly $95 million project to seismically retrofit the Big Hansen Dam that was completed in 2012.

Several other smaller projects were also launched, including a $2 million valve and spillway project at the Santa Anita Dam, seismic modification work at the Eaton Wash Dam, and planned structural repairs for the Whittier Narrows Dam.

Mark Pestrella, Assistant Director of Public Works, told KNX 1070 NEWSRADIO many of the big local dams like the Hansen Dam and Santa Fe Dam are operated by the Army Corps of Engineers and haven't been maintained as regularly as they should be.

"I would say that the federal government has not been as focused as it should be on that maintenance, and so on a regular basis we are advocating for better maintenance of those facilities," Pestrella said.

Hansen Dam and other reservoir facilities owned by Los Angeles County (PDF) protect about 10 million every day from flood risks during rainstorms and also play a role in water conservation, according to Pestrella.

But even after spending nearly $165 million on rehabilitation efforts on over half of the dams countywide since the early 1970s, Petrella said officials must continue to be proactive in preparing for the next big event.

"Being flood-ready is not something you do on the day of a flood," he said. "We prepare as if the great flood is coming every year without hesitation, and we invest like that's gonna happen, not only in our people, but in the facilities."

The Army Corps of Engineers has determined the 56-year-old Whittier Narrows Dam to be among those facilities at risk of overtopping during a major storm and potentially posing a threat to an estimated 1 million residents downstream, according to the Whittier Daily News.