DWR and the Ongoing Saga of Oroville Dam
2017 flood waters pour from Lake Oroville into the damaged spillway with incredible force and scour the hillside. The Oroville Spillway Incident gained national attention at the time. Credit: CA Dept. of Water Resources.
The Yuba River is the major tributary of the Feather River. On the Feather River lies some big reservoirs. The biggest is the Oroville Dam, the keystone of Governor Pat Brown’s State Water Project (SWP).
The issues with the poor foundation conditions under the Oroville Dam spillways became apparent during the work of the Yuba-Feather Workgroup. As far back as 2005, Friends of the River led a coalition of environmental organizations asking FERC to confront these problems as part of the relicensing of Oroville Dam.
The owner of the dam (the California Department of Water Resources (DWR)) and the State Water Project contractors persuaded FERC to reject our concerns. It took the dramatic 2017 spillway incident to demonstrate the truth of our claims.
After the spillway incident, DWR reconstructed the main service spillway, and the auxiliary spillway now has a hilltop roller-compacted concrete apron below the spillway lip. On an interim year-to-year basis, DWR is carrying the reservoir lower in the flood season
But there are at least two major problems remaining: (1) The spillways are 120,000 cfs short of capacity to release the traditional hypothetical standard regulatory flood that spillways are supposed to be able to handle, and (2) Big chunks of the hillside below the auxiliary spillway will be torn off the hillside and clog the channel below if that spillway is used (see memo below for more information). The powerhouse could be damaged. DWR concedes that operations of the SWP could be seriously damaged for as much as five years.
Big problems. Very big problems.
DWR, however, no doubt driven by SWP contractor cost-containment concerns, takes the position that there are no immediate needs to fix the Oroville spillways.
FERC’s Division of Safety of Dams and Inspections may believe otherwise, but DWR is pushing back hard.
Our view is that the tallest dam in the United States needs to be able to safely, and without drama, fulfil its operational requirements. If we can’t count on dam owners and their regulators to do this, then we may need a lot more dam removals.
