When Isabella Dam was built back in the 1950’s northeast of Bakersfield it was hailed as a great engineering achievement. The structure held back the mighty Kern River to provide water for farmers and communities, and helped protect the Southern San Joaquin Valley from floods.
But a little over 10 years ago, the U.S. Army Corps of Engineers learned that the dam had three problems. Geologists discovered an active fault runs under the dam. Hydrologists learned that there was a risk the earthen dam could be overtopped during an extreme flood event, and engineers discovered the structure had seepage issues at the base. According to Kern County officials, in a worst case scenario with the reservoir full and a failure of the main dam, some parts of Bakersfield could be under 20 feet of water or more.
That possibility led the Corps, which runs Lake Isabella and the dam, to change the way they operate the dam lowering by water levels to reduce the risk, and to begin designing a solution. So just when will work be complete on fortifying the dam structure?
With heightened concerns in the public about the state of critical infrastructure following the spillway crisis at Oroville Dam in northern California, many are asking if Isabella Dam is safe. We recently spoke with Sam Winder, senior project manager for the Corps on the Isabella project about those safety and the pace of the retrofit.