California Water Chief Says Oroville Dam Emergency Spillway Worked

The head of California’s water agency on Tuesday repeated his assertion that an emergency spillway at the Oroville Dam worked, drawing an incredulous response from a state lawmaker who represents tens of thousands of people ordered to evacuate when it was feared erosion at the spillway could lead to catastrophic flooding.

Bill Croyle, acting director of the Department of Water Resources, faced lawmakers for the first time since the evacuations in February. Authorities feared a concrete wall at the top of the emergency spillway was on the verge of collapsing and sending a wall of water rushing uncontrolled through downstream communities.

“In my opinion it didn’t work at all,” said Assemblyman James Gallagher, a Republican who represents many of the nearly 200,000 people who were ordered to evacuate. “When it started flowing and we had that erosion cut back, to me that’s a failure. It didn’t work as designed.”

Croyle has controversially maintained since the days after the evacuation that the spillway did its job, though he’s acknowledged that the erosion was more severe than anticipated. He told lawmakers that experts did not expect water to cut through rock.

“I believe the emergency spillway worked,” Croyle said. “It performed an emergency function with the broken (main) spillway.”

Water flowed over the emergency spillway for the first time after damage to the main chute caused officials to limit releases. That was followed by a ferocious storm that dumped far more water than forecast, filling the lake much faster than anticipated.

Officials did not plan to use the emergency spillway but saw a surge of water rush into the lake over several hours.

“What we saw was not what was forecast,” Croyle said.

Lawmakers also questioned Croyle about details of the $275 million contract to shore up both the main and emergency spillway, including who negotiated it and what penalties or incentives it includes for the contractor.

Croyle said he didn’t know details of the contract but would provide them later.

Erin Mellon, a spokeswoman for the Natural Resources Agency, said after the hearing that the contract with Kiewit Corp. of Omaha, Nebraska covers work through January 2019. That should be enough time to repair the entire main spillway and shore up the emergency spillway, she said.

By Nov. 1, officials plan to get the main spillway in strong enough condition to handle 100,000 cubic feet per second of water, with the ability to handle an additional 50,000 cfs in an emergency, Croyle said. It may take until next year to fully reconstruct the chute to handle its original maximum capacity of 270,000 cfs – a flow that would destroy downstream levees and cause widespread flooding but would protect the dam during a catastrophe, Croyle said.