California is blowing up Oroville Dam’s spillway in order to replace it

The main spillway of Lake Oroville Dam, California, whose major damage in February 2017 threatened the region with flooding and forced 200,000 people to evacuate, is now being demolished.

Damage caused by erosion in both primary and emergency spillways of Oroville Dam was one of this year's most memorable disasters. After a period of severe winter storms, Oroville Dam had almost reached its water capacity on February, thus managing authorities had started to release water from the lake, when a hole almost the size of a football field and at least 40-feet deep formed in the lower part of the main channel, due to erosion. The dam's emergency spillway was then put into use, but when it also started eroding, the immediate evacuation of people living in the surrounding areas was ordered, under the threat of flooding.

Flooding was eventually avoided, but now, that the rainy season is over, the California Department of Water Resources is working to replace the entire spillway infrastructure, which was doomed to fail, according to an independent analysis by Robert Bea for the Center for Catastrophic Risk Management at UC Berkeley. Replacing the spillway involves using controlled explosions to break up the cement, and this is what the Department is working on this month.

A large team of contractors in concrete, gravel and trucking are currently working on the project and have been paid millions of dollars by the state, according to the Sacramento Bee. The Department estimates the new spillway construction will be completed by November 1, 2017.