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Water Levels At Lake Oroville Drop

CADWR / Facebook

This aerial view looks east toward Oroville Dam and Lake Oroville, showing the damaged spillway with its outflow of 100,000 cubic feet per second (cfs) at the Butte County site. Photo taken February 15, 2017.

CADWR / Facebook

 


UPDATE: 1:45 p.m.:  (AP) - A California lawmaker wants to require more spillway inspections in the wake of evacuations prompted by damaged spillways at the country's tallest dam.

Assemblyman Marc Levine announced the legislation Friday.

Days earlier, nearly 200,000 people were evacuated for fear the emergency spillway at Oroville Dam in Northern California would fail.

The San Rafael Democrat's bill would require annual physical inspections for all auxiliary spillways on state-managed dams.

Officials diverted water to the Oroville Dam's emergency spillway over the weekend after severe erosion damaged the main spillway. The emergency spillway had never been used. Levine's office says the state performed visual inspections of the dam annually that found the spillway appeared to be stable.

Levine called the visual inspections "not good enough" and said physical inspections are essential for public safety.


UPDATE: 1:37 p.m.: Despite ongoing and incoming storm systems, California's Department of Water Resources will continue to reduce the amount of water coming down the damaged main spillway at Lake Oroville.

Earlier this week, 100,000 cubic feet per second of water was being released. That was dropped to 80,000 cfs yesterday.

Engineers reduced the amount again to 70,000 cfs Friday, and plan to drop it to 60,000 tomorrow.

DWR Acting Director Bill Croyle says lake levels are at a point that his team is confident increased inflow to the reservoir will not create an immediate problem. He says the drop in outflow is necessary for several reasons.

Another reason the flow is being reduced is so that crews can get started on debris removal work at the base of the main spillway in the diversion pond. 

DWR is hoping to re-start the Hyatt Power Plant that sits on the pond, but can't until water levels drop.

Randol White / Capital Public Radio

 


UPDATE: 10:26 a.m.: The level of the Oroville reservoir has been reduced by 40 feet to accommodate inflow from current and expected storms and is not expected to exceed anticipated outflows.

Officials had been releasing 100,000 cubic feet of water, or enough to fill an Olympic-size swimming pool, each second from the lake since Sunday, when the sheriff ordered an immediate evacuation. It was reduced to 80,000 cubic feet of water per second late Thursday.

Officials slowed the release of water from the lake behind the nation's tallest dam so crews can remove debris from the bottom of the structure's damaged spillway.

State Department of Water Resources officials say that removing debris protects Oroville Dam's power plant and will allow for it eventually to be restarted.

Meanwhile, two trails near the damaged spillway remain closed, but boat ramps at the lake remain open.


Original Post:  (AP) - Officials with the California Department of Water Resourcs say work crews are making good progress repairing Oroville Dam's emergency spillway to prevent further erosion. They say they are confident the damaged spillway and eroded hillside can withstand the stormy weather through the weekend.

There were three areas where erosion caused the most concern about potential flooding. One area has been 100 percent repaired, while the others are partially fixed.

On Thursday, officials slowed the release of water from Lake Oroville so crews can remove debris from the bottom of the damaged spillway.

Officials say removing debris protects Oroville Dam's power plant and will allow for it eventually to be restarted.

Meanwhile, a report prepared for crews responding to damage at the dam suggests rain may have contributed to a massive crater in the main concrete spillway.

An "incident status summary" prepared by a CalFire official on Saturday says the spillway "was compromised during heavy rains." It says water was diverted toward the hillside next to the spillway, undermining the concrete structure and causing a portion to collapse.

The spillway damage caused a series of events that led authorities to order nearly 200,000 people to evacuate Sunday.

CalFire spokesman Richard Cordova says the document is an internal status update issued every 12 hours. It was first published by the Los Angeles Times on Thursday.

Cordova says complete cause of the damage is still unknown.

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