The Los Angeles County Board of Supervisors, mindful of the massive evacuation resulting from damage to the Oroville Dam spillway in Northern California, asked Tuesday for a review of local dam safety and pending high-priority flood control projects.
“It is important that we ensure our flood control system is operating safely and efficiently,” while also assuring residents that county “engineers are constantly monitoring our dams,” Supervisor Kathryn Barger said.
The board’s vote was unanimous in favor of Barger’s motion. A report is expected back in 30 days.
In a briefing at the supervisors meeting, Department of Public Works Acting Director Mark Pestrella warned that rain forecast to begin early Friday and last into the weekend will likely create mud flows in Duarte and possibly some controlled flooding near Devil’s Gate Dam.
Pestrella also offered an update on the Oroville Dam situation, telling the board that flood managers were “confident” that the water level was being brought down enough that the compromised emergency spillway would not have to be utilized during an upcoming round of storms. However, “Mother Nature has a way of throwing curveballs,” he added.
The Oroville dam was designed for a 100-year-event but has recently seen multiple storms of that scale, Pestrella said.
Despite all the rain locally this winter, Los Angeles County has not experienced the same levels, according to Pestrella and Barger.
However, county workers are diligently prepping for the next round of sometimes heavy rainfall expected soon in the Southland, which Pestrella said “could — and most likely will — produce mud flows.”
Pestrella highlighted cleanup at the Las Lomas debris basin in Duarte, which has been challenged by heavy rains and the loss of natural flood barriers in last summer’s Fish Fire.
Another critical area and the county’s “most vulnerable” dam is Devil’s Gate in Pasadena, the oldest of the county’s 14 dams, Pestrella said.
There’s no storage for debris behind that dam and the county’s plans to clear out sediment have long been blocked by environmental groups.
During a hearing in a downtown courtroom Tuesday on the matter, a judge asked for additional briefings on environmental issues to be heard on March 23. Pending that hearing, he issued a tentative ruling to allow the county to proceed with the full scope of its plans to excavate 2.4 million cubic yards of dirt, denying requests by environmentalists to limit the project to half that size, KPCC reported.
In the meantime, Pestrella said, storms may force workers to use an emergency valve on the dam to release water.
“We’re monitoring the area very, very closely,” Pestrella told the board, while Barger stressed that there isn’t an issue with regard to the integrity of Devil’s Gate Dam.
Pestrella agreed that water is “designed to flow over. It’s not a failure of the dam. It’s the way we would expect it to operate.”
Supervisor Janice Hahn recalled when the Baldwin Hills Reservoir failed in 1963, killing five people, destroying dozens of homes and damaging roughly 200 more.
“I remember that morning very well,” Hahn said. “A lot of people think it couldn’t happen here, but it did.”
Supervisor Sheila Kuehl lived in the Baldwin Hills area at the time of the flood. She told her colleagues she bought blow-up rafts and “charged everybody a quarter to row across Rodeo Road,” pocketing about $5 in proceeds.
-City News Service