Tuesday, February 7, 2017

Concrete erosion halts Oroville Dam spillway flows

From a news release:
The Department of Water Resources has temporarily suspended flows from the Oroville Dam spillway to investigate concrete erosion on the bottom half of the spillway. There is no anticipated threat to the dam or the public.

Approximately 20 percent of Lake Oroville remains empty, and DWR officials say there is sufficient storage room to capture the inflow of the rain showers expected through the rest of the week. The reservoir, 3.5 million acre-feet at full capacity, now holds 2.8 million acre-feet, as prescribed by flood control operations.

Tuesday morning, approximately 60,000 cubic feet per second (cfs) was being released to the Feather River, all but roughly 5,000 cfs of it through the dam spillway. The remaining flows passed through the Hyatt Power Plant within the left abutment of the dam. DWR employees noticed an unusual flow pattern and erosion on the spillway, and they are investigating.

Flows from the spillway were gradually reduced until they were entirely halted around noon Tuesday. Sufficient capacity exists within the reservoir to capture projected inflows for at least three days, and DWR expects to resume releases from the gated spillway at a rate deemed safe later today after a thorough inspection is performed.

In order to avoid a drastic reduction of flows in the Feather River downstream, DWR is increasing releases from Thermalito Afterbay – a small reservoir just downstream of Oroville Dam. DWR will keep the public apprised of the situation with regular updates.

No comments:

Post a Comment