The Trillion-Gallon Question : What if California’s Dams Fail ? - The New York Times
▻https://www.nytimes.com/2023/06/22/magazine/california-dams.html
Un (très) long papier absolument passionnant sur l’état de la maintenance des barrages en Californie.
Prévoir, c’est dépenser (beaucoup) d’argent, peut être inutilement quand il s’agit de sécurité contre des événements extrêmes, mais justement, c’est cela la sécurité : prévoir au mieux les événements. Or face au changement climatique, l’attitude des pouvoirs publics et des entreprises est surtout de minimiser les conséquences possibles pour ne pas investir maintenant dans l’entretien et la mise à jour des infrastructures.
On the morning of Feb. 7, 2017, two electricians were working on a warning siren near the spillway of Oroville Dam, 60 miles north of Sacramento, when they heard an explosion. As they watched, a giant plume of water rose over their heads, and chunks of concrete began flying down the hillside toward the Feather River. The dam’s spillway, a concrete channel capable of moving millions of gallons of water out of the reservoir in seconds, was disintegrating in front of them. If it had to be taken out of service, a serious rainstorm, like the one that had been falling on Northern California for days, could cause the dam — the tallest in the United States — to fail.
Dale Cox, a former project manager at the United States Geological Survey who has worked extensively with Swain, told me that California’s dams are unprepared for extreme weather because state water authorities have a false sense of how bad flooding can get. “The peak of record is driving a lot of engineering decisions in the state,” he says, and that peak is an underestimate, maybe a gross one. “Already, we are seeing several 100-year floods every 10 years.”
Some of this miscalculation arises from our failure to account for climate change, a problem that will only get worse as the atmosphere heats up and the amount of water vapor it can carry increases. “All of this infrastructure,” Swain says, “is designed for a climate that no longer exists.” But the error also lies in our understanding of the past. Most of the flood data that form the basis for the design of California’s dams come from the past century, which was an unusually placid period in the state’s weather.
