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Oroville – Something was wrong with the Oroville Dam spillway weeks before the Department of Water Resources noticed a hole in the concrete.

Two photos taken by photographers from this newspaper show discoloration and possible damage to the concrete of the spillway at the spot where a gaping hole opened Feb. 7. Those pictures were taken Jan. 13 and Jan. 27.

When asked for a response to the photos, California Natural Resources Agency deputy secretary for communication Nancy Vogel wrote in an email to this newspaper, “Oroville dam was frequently inspected by multiple state and federal agencies. Reports of those inspections did not reveal any major causes for concern. DWR will soon name a panel of independent experts to investigate the cause of the main spillway failure and ascertain if such a failure could occur again. We hope that what we learn about the cause of this incident and how to prevent it elsewhere will help dam owners around the world.”

She did not ask to view the photos.

So why didn’t the water agency see what the pictures show?

The answer may have to do with inspections of the dam and spillway.

Before Feb. 7, the last inspection on the entire spillway structure by DWR was Feb. 3, 2015. Despite claims the department performed inspections twice per year, the spillway had not been fully inspected with operations and maintenance workers on the concrete in just over two years, according to a DWR spokeswoman, before a worker noticed the concrete breaking up on his way to work this Feb. 7.

After the February 2015 inspection, there were inspections of the dam by the DWR in July 2015 and August 2016, but those didn’t involve workers walking on the spillway getting a close look.

“During annual inspections, the Oroville Dam, and its appurtenances, have been repeatedly found safe for continued use, which includes the emergency spillway,” Vogel wrote.

The reason for the lack of complete spillway inspections is, presumably, safety.

“DWR (operations and maintenance) could not inspect the flood control spillway by walking it immediately before and after the spillway was used in March 2016, because the lake elevation was too high — there was water behind the radial arm gates at the top of the flood control spillway,” Vogel wrote. “Typical DWR safety protocol does not allow people to walk in the spillway when water is against the radial gates on the lake side.”

Nearly a year ago, on March 24, 2016, the flood control gates at the top of the spillway opened for the first time in five years.

The spillway was not fully inspected by DWR before or after that event. It took nearly five months before the department checked the dam structure in August 2016, and only a visual check was performed on the concrete spillway.

The Federal Energy Regulatory Commission inspected the dam May 25-26, 2016, and found nothing wrong at that time. But because DWR’s July 2015 review was a joint inspection with FERC and the July 2015 DWR review did not fully inspect the spillway, it’s unclear whether the commission’s annual 2016 inspection fully reviewed the spillway.

A five-year review board also didn’t find anything wrong.

“The most recent 2014 Oroville Dam federal and state board of independent experts concluded that there was no reason to expect either spillway to fail under operation,” wrote Maggie Macias of the Department of Water Resources public affairs office.

Two years after that board met, water was released for the first time in five years. Three years after the board met, the spillway broke and the structure was ruined. It has been more than a month, and the cost is estimated to be $4.7 million per day, or about $150 million to date.

Early rough estimates by DWR acting Director Bill Croyle put the cost to either fix the existing spillway or build a new one are between $100 million and $200 million.