Press conference explaining the plan to fix Oroville Spillway
Responding to criticism about secrecy around the Oroville Dam repair effort, California officials released two redacted reports Monday from outside engineers consulting on plans to fix the dam’s battered spillways.
The California Department of Water Resources disclosed a pair of memos from its board of consultants – four engineers advising the department on the massive repair project. DWR officials defended their decision to redact portions of the documents, saying it’s a matter of national security, as well as their continued decision to keep other documents and reports completely under wraps.
“Dams could actually be used in an act of terrorism,” said David Gutierrez, a DWR consultant, in a conference call with reporters. “One of those things you obviously don’t want to do is highlight vulnerabilities.” Gutierrez is a dam-safety expert and former DWR official, although he isn’t part of the four-member consulting team whose reports were released Monday.
The consultants’ first report, which was made public in March, provided the earliest insights into the enormity of the problems facing DWR. For the first time, it became clear that the repair of Oroville’s two spillways likely would take two years to complete. DWR officials said the report shouldn’t have been made public and sealed follow-up documents, triggering a bipartisan outcry from elected officials, environmentalists and others.
The second and third reports, released Monday, provide more analysis as DWR’s repair plan took shape in the last two weeks of March. In some cases, the consultants question the direction DWR has taken, although Gutierrez said the consultants and DWR are largely on the same page. The state has hired Omaha, Neb., contractor Kiewit Corp. to handle the $274 million repair job.
“The board of consultants is pretty much concurring with the approach the department is taking all the way along,” Gutierrez said.
For instance, the consultants agreed with one of the more striking elements of DWR’s plan. Because the main spillway probably can’t be completely repaired this year, DWR officials have said they might have to allow excess water to flow out of the side of the concrete chute and down the carved-out hillside next to the spillway. Because the spillway would be mostly fixed by fall, the consultants believe “the possibility of needing to route discharge down the gully is small,” they wrote in their March 31 report.
In a recommendation cheered by environmentalists, the consultants said as part of a long-term repair plan, the state should consider replacing the emergency spillway with a gated auxiliary spillway equipped with a “fully-lined chute.”
The main spillway cracked in two on Feb. 7, prompting dam officials to shut off water releases temporarily as a major storm rolled into the region. Four days later, with Lake Oroville rising to the top, water flowed for the first time ever over the adjacent emergency spillway, a concrete lip perched atop an unlined hillside.
The next day, with the hillside eroding severely, officials ordered the evacuation of 188,000 residents amid fears the emergency structure was going to fail. Dam operators dramatically ramped up outflows from the main spillway, halting the flow of water over the emergency spillway and preventing it from failing.
More than a decade before the emergency spillway nearly washed away, environmental groups and local agencies had been calling on the DWR to build a functional chute below the emergency structure. As a temporary fix, crews have shored up the hillside with concrete and rock, and are planning over the next two years to further line the hillside with concrete.
Ron Stork, a senior policy advocate at Friends of the River, applauded the recommendation. He said the need for a functional concrete chute “seems like a statement of the blindingly obvious.”
The release of the two documents was cheered by state Sen. Jim Nielsen, R-Gerber, and Assemblyman James Gallagher, R-Yuba City, who represent the Oroville area and have been demanding greater transparency from DWR. In a joint statement, they called the release “a big step in the right direction.”
The disclosures, however, leave several DWR documents still under seal, including a “project safety compliance” report from late March and documents from mid-April on access road construction and geotechnical inspections of the spillway area. In addition, DWR officials have refused to release documents related to the competitive bidding on the repair project.
DWR officials say they plan to release additional redacted reports from the outside consultants as they become available.
In justifying their secrecy, DWR officials have cited a set of regulations called “critical energy infrastructure information,” developed by the Federal Energy Regulatory Commission soon after the Sept. 11, 2001, terrorist attacks. FERC licenses the dam and its hydroelectric plant and is overseeing the repairs.
The disclosure followed weeks of criticism from elected officials about DWR’s secrecy. It came one day before a scheduled hearing at the state Senate Natural Resources and Water Committee on the Oroville investigation and repair plans.
A preliminary analysis by DWR’s board of consultants, published in March, suggested that design flaws played a role in fracturing the main spillway. That conclusion was supported by an independent report released last week by Robert Bea, an expert on dam safety at UC Berkeley.
Newly released redacted documents
Second memo from the board of consultants on the Oroville spillways:
Third memo from the board of consultants on the Oroville spillways: