Lessons to be Learned from the Oroville Spillway Incident
Stephen Rigbey, President SJR Consulting and former Director of Dam Safety at BC Hydro
Stephen was a member of the Independent Forensic Engineering Team that investigated the Oroville Dam Incident.
The Oroville Dam and its associated reservoir and hydropower facility is located on the Feather River in Northern California and is owned and operated by the State of California Department of Water Resources. This earth embankment is the tallest (770 ft. high) in the United States. Its reservoir (Lake Oroville) at 3.5 million acre-feet of storage is the second largest reservoir in California and supplies water as far south as Los Angeles.
Winter storms during the winter of 2016-2017 brought record precipitation to the Feather River watershed. In early February during a controlled water release over the primary spillway, there was a major failure of the spillway chute at its approximate midpoint. Concern about the spillway condition curtailed its use and lead to reservoir build up to the point where the emergency spillway was activated. However, even relatively small flows over the emergency spillway lead to severe erosion and the potential failure of the embankment structure. The threat of a potential failure led to the forced evacuation of between 188,000 and 200,000 people. Based on this situation the primary spillway was reopened and further damage occurred. Due to continued precipitation, it was necessary to use the primary spillway intermittently over the next three months. That use resulted in additional deterioration.
The presentation contains numerous photographs and video during and after the events. It will start with some background on the events that occurred in February 2017, identify the extent of the damage, present findings associated with the forensic investigations, outline the preliminary repairs to the primary spillway and finally discuss the lessons learned from this incident.
This program is pending for 1 PDH Credit
ASCE Member: $25.00
NYSSPE Member: $25.00