The Association of State Dam Safety Officials and the United States Society on Dams are partnering to examine the February incident at California’s Oroville Dam.
The voluntary joint task force, being called the Oroville Spillway Incident Forensic Investigation Team, brings together ASDSO and USSD members from around the world “in a spirit of cooperation and support” with cooperation from the California Department of Water Resources, the organizations said in a joint statement.
“[The task force] emphasizes the need for a comprehensive, independent investigation to ensure that the possible causes of the incident are evaluated based on the most accurate and complete information available,” the groups said, emphasizing the need to determine how human and organizational factors might contribute to dam safety incidents.
ASDSO and USSD issued a preliminary memorandum last month about potential physical factors that might have led to the Oroville spillway failure for consideration in the design and construction of repairs, but said it is necessary to consider all factors in its study.
To that end, the task force’s human and organizational factors analysis will be led by BC Hydro’s director of dam safety, Stephen Rigbey, and ASDSO committee member Irfan Alvi, who has helped develop a number of protocols for investigating dam failures and incidents.
Other team members include independent experts in the fields of geotechnical engineering, hydraulics, hydraulic structures and engineering geology, with overall guidance from AECOM vice president John France.
“It is important that the team is given the necessary time needed and the patience of all stakeholders to do a thorough investigation,” the group said. “The investigation is in the early stages and much work remains to be done before the investigation is complete.”
HydroWorld.com reported February 8 that DWR had suspended flows over Oroville Dam’s main spillway as officials began investigating concrete erosion on its bottom half. The suspension of releases over the main spillway, coupled with heavy rain in the region, led to releases from the dam’s auxiliary earthen spillway and the fear that a failure caused by further erosion could result in catastrophic damage downstream along the Feather River.
DWR resumed operation of Oroville’s flood control spillway on March 17 before beginning to drop water levels in Lake Oroville several days later.
DWR then awarded Kiewit Infrastructure West a contract in April to begin immediate repairs on Oroville’s failed spillways in advance of the region’s wet winter season.
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