Summer has not yet begun, and the level of Lake Oroville, the second-largest California dam that supplies much of the state, is already half as high as usual, a worrying symptom of worsening chronic drought in the region.
As of May 10, California Governor Gavin Newsom has declared a state of emergency related to the drought in more than 40 counties. Butte, where the Oroville Dam is located, is already classified at an “exceptional” level, the highest.
And the situation, exacerbated by the effects of climate change in the western United States, is not expected to improve until precipitation returns in five or six months.
“The reservoir level is much lower than we would like, much lower than usual at this time of year. That’s about 47% of the average,” said John Yarbrough, an AFP official with the California Department of Water Resources, pointing to the cracked earth that makes up the lake’s walls. .
In 2019, the “good year”, the water reached an alley bordering the dam, about fifty meters higher than it is now, the expert recalls.
Locals interviewed by AFP say they have never seen this. And many, disbelieving, refer to February 2017, when they had to evacuate the area because the dam overflowed under the influence of heavy rains and risked swallowing them.
– Snow evaporates –
“When we enter a year like this with low bedding and really dry conditions across the state, there’s cause for concern,” says John Yarbrough.
Because Lake Oroville, built in the 1960s at the confluence of three rivers, is a key element of the “state water project,” a colossal network of 21 dams and more than a thousand miles of canals and pipes leading from northern California to a more populated and much drier south.
“This lake provides drinking water for 27 million Californians, and irrigates up to 300,000 acres of farmland,” he said.
Northern California receives an average of two-thirds of total California rainfall, but this year has been particularly poor.
As of April 1, which traditionally marks the end of snowfall, snow reserves in neighboring Sierra Nevada – the source of about a third of the water used in California – were only about 60% of the average.
“What’s really unique about this year is that when the snow melted, the runoff ended up leaking into the dry soil and evaporating,” without actually reaching Lake Oroville to increase its reserves, John Yarbrough explains.
The highest dam in California (234 meters) will not be dry soon, but by the end of the dry season it was supposed to reach the lowest level recorded in September 1977.
– Fear of forest fires –
After two years of particularly light rain and without any guarantee of improvement in the coming seasons, water restrictions are already on the agenda. The Department of Water Resources, which manages the State Water Project, has warned that it may not be able to meet more than 5% of the requirements set for this year …
And the owners of several dozen boats moored on Lake Oroville were forced this week to pull them out of the water, otherwise they could run aground and be damaged.
Another serious consequence of the drought: an increased risk of fires, which is of particular concern in a region that has been ravaged on several occasions in recent years by forest fires of extreme intensity.
The burnt trees that stand on the heights of Lake Oroville are here to remind you: last year in California alone, more than 17,000 km2 of smoke burst, and 33 people were killed in the blaze, including 15 in Berry Creek, at the gates of Oroville.
And this year in California, fires have already swallowed five times more vegetation at the same time than last year.
“We’re in a long-term trend of drought conditions. It’s been going on for about six years, and it’s coming a few wet years. But overall there’s a lot of drought than we’re used to,” sums up John Messina, Butte County Fire Chief.
“The more fuel the drought, the greater the risk of a catastrophic forest fire. Or at least of an extremely turbulent summer …”