State water engineers are pushing back against a UC Berkeley professor's warning about potentially dangerous leaking at Oroville Dam. The Water Resources Department says the green, wet spots near the top of the left abutment are just the result of natural vegetation that has appeared after every wet winter during the dam's entire 50-year history.
They also say all earthen dams seep a little, and Oroville's seepage is remarkably small considering it's the tallest dam in the United States. The report of potential trouble came last month from retired engineering professor Robert Bea, who investigated levee failures around New Orleans after Hurricane Katrina in 2005.