The Los Angeles County Board of Supervisors has ordered a sweeping inspection of all county dams, spillways, drainage basins, and other flood control infrastructure. The action was prompted by the recent emergency situation at Lake Oroville in Northern California, when failures of two spillways used to lower the lake’s water level prompted mandatory evacuation orders for more than 100,000 people in communities below the imperiled Oroville reservoir.

The supervisors have asked the county’s Department of Public Works to provide a report on the condition of the dams within 30 days and to develop a list of priority flood-control infrastructure projects that need to be completed.

County Supervisor Kathryn Barger called for the inspections. The county operates 14 dams and reservoirs. Thirteen of those are in Barger’s district, which includes much of the San Gabriel Valley, foothill communities of the San Fernando Valley, and the Antelope Valley.

“The Oroville situation reminds us of the need to proactively evaluate our county’s risk with regard to dams and other facilities which may be prone to failure from storms, earthquakes or other foreseeable events,” Barger said in a statement.

L.A. County’s flood control infrastructure is aging — it includes 500 miles of open channel, 2,800 miles of underground storm drain and an estimated 120,000 catch basins. Yet many of the county’s dams and related structures were built in the 1920s and ‘30s.

L.A. County has experienced catastrophic dam collapses in the past. When the St. Francis Dam in the Santa Clarita valley collapsed in 1928, as many as 600 people died. The catastrophe sent 12 billion gallons of water, carrying mud, boulders, trees and debris, crashing down San Francisquito Canyon. In 1963, the Baldwin Hills Dam ruptured, sending a 50-foot wall of water cascading down Cloverdale Avenue. Five people were killed, 65 hillside homes were destroyed, and more than 200 other homes and apartments were damaged.

“Any of our cities in the foothill communities below a dam could be impacted by a catastrophe,” said Tony Bell, Barger’s spokesman. “We need to make sure those are safe,” said Bell adding that the cost associated with proactive care “pales in comparison” with any potential disasters.

Source: Los Angeles Times