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