A California dam in the midst of a federal relicensing process has experienced flooding and storm-related damage, prompting the evacuation of over 180,000 people. Evacuation orders and a reservoir drawdown represent the most rapid responses to the Oroville Dam incident -- but future discussions of engineering, dam safety, and public policy are likely to continue after the emergency has been resolved.
Oroville Dam is the tallest dam in the U.S.: a 770-foot high earthfill embankment dam on the Feather River in northern California. The dam was built from 1961-1968 by the California Department of Water Resources, as part of the State Water Project. The resulting impoundment, Lake Oroville, can store over 3.5 million acre-feet of water, making it California's second largest man-made lake.
The Oroville project is subject to licensing by the Federal Energy Regulatory Commission under the Federal Power Act. Its first license was issued on February 11, 1957, for a 50-year term which expired on January 31, 2007. The Department of Water Resources filed an application for a new license for the project, which remains pending in Docket No. P-2100, although a settlement agreement was also filed. In the meantime, the project continues to operate under a series of annual licenses issued by the Commission. According to a DWR website, it "anticipates that FERC will issue a new license order in 2017
pending issuance of the aquatic biological opinion from the National
Marine Fisheries Service."
According to state documents, California was hit by three major storms during January and February 2017, with major rain and runoff. As Lake Oroville reached its full capacity, operators opened a spillway to allow excess water through the dam. But on February 7, the spillway began to
erode. Four days later, operators opened the auxiliary emergency
spillway, but eventually determined that this too was "in danger of failing." Since a failure could cause widespread and severe flooding, officials called for evacuations downstream in the Feather River Valley. On February 12, Governor Edmund G. Brown Jr. issued an emergency order strengthening the state's response.
Focus for now remains on safely resolving the risks that the Oroville Dam or its spillways might fail in a way that releases damaging waters. The Commission could investigate what happened under its authority over the project through its existing license. It could also raise issues relating to the incident in the context of the project's relicensing. That case has been pending for roughly a decade, with a settlement agreement having been reached years ago. But it is possible that the 2017 Oroville Dam incident could have consequences in the relicensing context, such as revised spillway designs or operating plans that could be reflected as conditions in a new license.