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Thousands told to evacuate in face of California dam risk

February 14, 2017 | Expert Insights

On 12 February 2017, at least 130,000 people have been asked to evacuate over concerns California's Oroville Dam's emergency spillway could fail. The tallest dam in the US was weakened by heavy rainfall. Authorities issued emergency evacuation orders for tens of thousands of people living downstream from Northern California’s Lake Oroville, after an auxiliary spillway that was put into service over the weekend appeared in danger of failure due to erosion. The emergency spillway of the Oroville Dam could collapse at any moment.

Water levels in the reservoir have been rising because of heavy rain and snow in California following years of severe drought. It is the first time that Lake Oroville has experienced such an emergency in the dams near 50-year history. It was releasing as much as 100,000 cubic feet (2,830 cubic metres) of water per second from the main spillway to try to drain the lake. Last week engineers began releasing water from the dam after noticing large chunks of concrete were missing from a spillway. Residents of Oroville, a town of 16,000 people 65 miles (105km) north of Sacramento, have been told to head north. Other cities affected should follow orders from their local law enforcement agencies.