Water & Drought

Groups demand transparency on Oroville Dam spillway repairs

Oroville dam break would flood almost 200,000 California residents in 7 hours

This animation details a worst-case scenario in Oroville, Calif.: dam failure. With 3.5 million acre feet of water held behind the dam, floodwaters would pour through a huge section of Northern California. Residents closest to the dam would have j
Up Next
This animation details a worst-case scenario in Oroville, Calif.: dam failure. With 3.5 million acre feet of water held behind the dam, floodwaters would pour through a huge section of Northern California. Residents closest to the dam would have j

A coalition of environmental groups that had warned Oroville Dam’s emergency spillway was fatally flawed long before it nearly washed away this winter is demanding that federal regulators open up dam repair plans for public vetting.

In a filing Wednesday with the Federal Energy Regulatory Commission, a coalition of environmental groups led by Sacramento-based Friends of the River also said it was concerned that the state Department of Water Resources is only going part way in repairing the emergency spillway.

DWR’s repair plan calls for replacing the dam’s main spillway, which cracked in two in early February, and partially lining the emergency spillway with concrete.

Ron Stork, a policy analyst at Friends of the River, said the plan for the emergency spillway makes sense but only as an interim measure. He said the ultimate goal should be to line the emergency structure from top to bottom. “You want a spillway all the way down the hillside,” he said in an interview.

In 2003 through 2005, three environmental groups – Friends of the River, the South Yuba Citizens League and the Sierra Club – urged the federal government to require the lining of the emergency spillway as part of the dam’s licensing process. The demand was brushed off by state and federal regulators and the water districts that store water in Oroville. The water districts would have had to pay for the upgrades.

The dam’s main spillway cracked in two Feb. 7, prompting a temporary shutdown of the structure as a major rainstorm rolled through. Lake Oroville filled so high that water flowed over the emergency spillway for the first time ever. On Feb. 12, dam engineers feared erosion on the hillside beneath the emergency spillway was compromising the integrity of the spillway itself. Officials ordered the evacuation of 188,000 residents for two days. Disaster was averted when dam engineers dramatically ramped up water releases from the damaged main spillway, arresting the flow of water over the emergency structure.

Stork also complained that federal regulators are allowing state officials to keep documents detailing repair plans and investigations under wraps. In its letter to FERC, the coalition said the process needs to be opened up to the public. Federal and state officials have cited national security concerns for keeping the documents secret, although DWR officials have said they might release redacted versions of some documents.

“We don’t even know what the department is thinking because of the transparency issues,” Stork said in the interview.

Ryan Sabalow: 916-321-1264, @ryansabalow

Related stories from Sacramento Bee

  Comments