Oroville Dam: A failure of epic proportion

As of last Sunday, the costs of the repair work on the dam’s emergency spillway had climbed to more than $10 million, according to the Los Angeles Times. By an official estimate, repairs on both spillways could ultimately cost as much as $200 million or more.

The trouble started when state officials began sending 100,000 cubic feet per second of water into the dam’s main spillway earlier this month to release storm runoff and prevent the lake from overflowing. The flows were halted after engineers discovered a gaping hole in the concrete spillway but it was too late. On Feb. 11, the elevation rose to 901 feet, causing water to flow over a weir into the dam’s spillway and carved a deep fissure into the support ot the 770-foot-tall dam.

With parts of Northern California forecasted to have the wettest winter ever recorded, officials warned that several other waterways are at major risk of flooding, including the Yolo Bypass, Clear Lake, and the Sacramento, Cosumnes, Mokelumne, Merced and Tuolumne rivers.