DWR: Progress at Oroville Spillway continues – KRCRTV.COM

Photo courtesy of the Department of Water Resources Photo courtesy of the Department of Water Resources

OROVILLE, Calif. - Crews continue to make progress as they work to remove an estimated 1.5 million cubic yards of debris at the base of the main spillway at the Oroville Dam.

To put the amount of debris being removed into perspective, 1.5 million cubic yards is nearly the size of the Houston Astrodome and could fill an Olympic-sized swimming pool 450 times.

Two days after the Department of Water Resources (DWR) halted flows down the damaged flood control spillway, debris removal at the base of the spillway continues in an effort to lower the water level in the channel. This is key to the reoperation of the Hyatt Power Plant. The power plant will give the DWR an additional way to release water from Lake Oroville.

60,000 cubic yards of debris have been removed since the flows were stopped and Lake Oroville is not expected to rise above 860 feet in elevation while the spillway flows are halted. If the lake were to reach the maximum expected level of 860 feet, the water would still be 41 feet below the emergency spillway.

As of 3 p.m. Wednesday, the lake was at 844 feet, 57 feet below the emergency spillway. Inflows are roughly 20,000 cfs which has resulted in roughly 3-feet of rise in lake elevation since Tuesday.

If the Hyatt Power Plant function is not restored within several days, the Department of Water Resources will use the flood control spillway again to regulate reservoir levels.

Once operational, the Hyatt Power Plant can discharge roughly 14,000 cfs, which will allow the DWR to better manager reservoir levels through remaining spring runoff season.

"Our crews are making fantastic progress removing debris from the area," said DWR Acting Director Bill Croyle. "We are working around-the-clock to get the power plant back online," added Croyle.

DWR does not expect the anticipated wet weather to interfere with debris removal or to create a lake elevation concern. The DWR will continue to monitor the weather forecast as the weekend approaches. The halt of flows has allowed theDWR to better assess the extent of erosion on the flood control spillway that was first noticed February 7. This information is critical to the long-term design of a repair.

Flows necessary to meet fishery requirement in the Feather River downstream of the dam are being maintained at 2,500 cfs through use of water stored in the Diversion Pool and Thermalito Forebay and Afterbay. This complex of small reservoirs just downstream of Oroville Dam will provide enough water to maintain flows for approximately six days.

DWR and the California Department of Fish and Wildlife together are continuing to survey the Feather River downstream of the Oroville Diversion Dam and rescuing fish that have become stranded in pools as the river level falls. Adult salmon are not expected to be in the river at this time of year. On Tuesday, about 500 juvenile salmon and a few steelhead trout were rescued.

Work continues on the area below the emergency spillway, access roads, and other areas eroded by the emergency spillway runoff. Rock benches and check dams are being constructed to slow water and erosion should the emergency spillway be required to be used again.

DWR continues to monitor the status of the dam, spillways, and the Hyatt Power Plant and the progress of repair activities. DWR is coordinating with Caltrans to address the impact of emergency response activities on local roads, and this will continue throughout the operation.

Biologists from Fish and Wildlife and the California Department of Water Resources worked to rescue fish stranded by the receding waters of the Feather River since the outflows from the damaged Oroville Dam spillway were stopped Monday. The fish were then released back into the Feather River.

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DWR: Progress at Oroville Spillway continues - KRCRTV.COM