Rebuilt Oroville Dam Spillway Develops Small Cracks

SAN FRANCISCO (AP) -- California state officials say small cracks that have appeared in the brand new concrete spillway at Oroville Dam were expected and do not pose a threat.

KQED radio of San Francisco reported Tuesday that previously undisclosed letters show federal regulators asked Department of Water Resources officials to explain the hairline cracks on the dam's new massive concrete flood-control chute.

In an October letter, the Federal Energy Regulatory Commission also asked water officials what, if any, steps might be required to address the issue.

California water officials responded in November that steps taken to build a more durable spillway caused the cracks and was anticipated. A Dept. of Water Resources spokeswoman said the cracks are not a cause of concern and do not to be repaired.

"This is a normal occurrence to happen on a construction project," said DWR spokeswoman Erin Mellon. "All concrete has this result in the placement. It's just physics of how concrete works."

University of California civil engineering professor Robert Bea says cracking in high-strength reinforced concrete structures is never expected.

TM and © Copyright 2017 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2017 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten. The Associated Press contributed to this report.