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 reports 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. Officials say that water will not be able to penetrate the cracks, which were described as superficial. And others say that hairline cracks actually aid in relieving stress on the structure by allowing it to flex.
University of California civil engineering professor Robert Bea says cracking in high-strength reinforced concrete structures is never expected.
Some residents in the area aren't convinced that the cracks don't pose a threat following the near disaster and evacuations last winter.