Records Raise Safety Questions Surrounding Oroville Dam – NBC Bay Area
All of the engineers told NBC Bay Area that the documents they reviewed raise serious safety concerns that they say must be addressed sooner rather than later or risk failure of Oroville Dam itself.
Among the issues are:
A 15-foot-long crack in the concrete at gate eight in the dam’s headworks, or flood control structure, which records show appears to be growing
Spalling, or deterioration, of concrete in other areas of the dam
Cracking tendons, or trunnion rods, that help move the 20-ton radial gates, which control the flow of water through the dam
Failure of the Department of Water Resources to develop a long-term plan to monitor the amount and speed of water that naturally flows through the earthen dam, despite a request by federal inspectors to do so
For many of the engineers, that last issue is the most troubling problem. In a 2010 report, federal inspectors ordered the California Department of Water Resources (DWR) to “establish a long-term plan to monitor the flow” of water through the earthen dam—what’s known as the phreatic surface. This issue subsequently appears as the top priority to be addressed in the past five years of DSOD inspection reports, yet DWR has, thus far, failed to create such a plan.