California Governor Edmund G. Brown has announced a series of immediate and longer-term actions to bolster dam safety, improve flood protection, and fix the state’s aging transportation and water infrastructure.
The Governor recently visited the Incident Command Post for Oroville Dam and surveyed the regional flood control system. On Feb. 24, he announced a four-point plan to bolster dam safety and flood protection. The state of California released a fact sheet detailing the plan:
1. Invest $437 million in near-term flood control and emergency response actions. The Governor will redirect $50 million from the General Fund and request a $387 million Proposition 1 appropriation from the legislature as soon as possible. This is in addition to the $634 million in Proposition 1E and Proposition 84 bond funds that will be spent on flood control in the next two fiscal years.
2. Require emergency action plans and flood inundation maps for all dams. About 30% of dams designed as high hazard do not have emergency action plans, and inundation maps are only filed when a dam is licensed and only consider complete dam failure. The Governor is proposing legislation to require EAPs for all dams the state regulates and will require inundation maps for all dams to be updated to incorporate new information and consider multiple scenarios beyond complete dam failure.
3. Enhance California’s existing dam inspection program. The Governor has directed the California Natural Resources Agency to conduct more detailed evaluations of dam appurtenance structures to include geologic assessment and hydrological modeling. This new review is to be expedited for dams that have spillways and structures similar to Oroville Dam before the next flood season.
4. Seek prompt regulatory action and increased funding from federal government to improve dam safety. Reservoir regulation procedures (rule curves) and operational manuals for many dams are outdated. The Governor has requested the federal government adopt the state’s new evaluations of dam appurtenance structures at federal dams, update the rule curves and appropriate federal funding for the newly created federal program to rehabilitate high-hazard dams.
With regard to transportation, the Governor said the same storms that damaged the state’s flood control system have “hammered the state’s roads and bridges.” According to the Governor’s website, he sent a letter to President Donald Trump on Feb. 24 “seeking expedited environmental review under Presidential Executive Order 13766” that covers nine high-priority transportation projects and reconstruction of the Oroville Dam spillways.
Beginning at 6:45 am today, the California Department of Water Resources, which owns and operates Oroville Dam, started gradually ramping down outflows from the reservoir through the flood control spillway, dropping from 50,000 cubic feet per second to zero in the afternoon. Flows from this spillway will cease for several days to “allow workers to aggressively attack the debris pile at its base and reduce the water level surface elevation of the channel that leads from the Hyatt Power Plant,” DWR says. Removing this debris will help safeguard the power plant and allow for its eventual reoperation.
On Feb. 26, DWR reported that Lake Oroville levels were at 842 feet, 59 feet below the maximum level of the reservoir.
Last week, HydroWorld.com reported that California DWR selected a five-person independent board of consultants to help investigate the cause of the main spillway failure at Oroville Dam and ascertain if the failure mode could occur again.