Torrential rains in California since the start of the year have filled the state’s water reservoirs. But reserve management remains fragile throughout the American Southwest, where the low level of the Colorado River has remained virtually unchanged.
The 12 atmospheric rivers that have hit the California coast since the start of 2023 have filled several large water reservoirs in the northern and central parts of the state. A glance at the California water resources map shows that current levels at Oroville, Shasta, New Bullards, Don Pedro, Camanche and other reservoirs are above their historical average.1.
PHOTO DAN REIDEL, ASSOCIATED PRESS ARCHIVES
Water flows from the main spillway at Oroville Dam in California on March 10.
Faced with this resurgence, Democratic Governor Gavin Newsom announced, on March 24, relaxations in the restrictions on water consumption.
But we must remain very cautious in the face of this good news. Because they come with some bad sides, explains Amir Aghakouchak, associate professor at the Center for Hydrometeorology and Remote Sensing at the University of California at Irvine.
PHOTO STEVE ZYLIUS, SUPPLIED BY UC IRVINE COMMUNICATIONS
Amir Aghakouchak, associate professor at the Center for Hydrometeorology and Remote Sensing at the University of California, Irvine
We went from extreme drought to high water levels in a very short period of time. This created severe flooding. People have died. It’s totally unusual here.
Amir Aghakouchak, associate professor at the Center for Hydrometeorology and Remote Sensing at the University of California, Irvine
According to Mr. Aghakouchak, this very contrasting phenomenon could repeat itself in closer sequences in the future. “In 2017, we experienced the same situation: a five-year drought suddenly stopped by major floods. We have to be prepared for more sudden changes. We cannot assume that we will experience long periods of calm. »
In the Salinas Valley, an area halfway between San Jose and Monterrey, the rain did cause significant flooding. The damage to agricultural land is considerable. The price of lettuce, grown in abundance in this region, should increase shortly and remain high for months.
Strawberry fields were also affected.
PHOTO ARCHIVES ASSOCIATED PRESS
Homes in San Clemente, California, found themselves in bad shape following the passage of the 11e atmospheric river, March 15.
“From north to south, wildlife, farmers and farm workers have not been spared,” confirms Chris Lopez, Monterey County Supervisor where the Salinas Valley is located. People’s jobs are affected. »
Little impact on the Colorado River
Another issue that should not be overlooked is the impact of recent rains on California’s groundwater levels. According to Alexis Maximilien Berg, assistant professor in the geography department of the University of Montreal, a winter of heavy rains will not succeed in raising them.
So much water has been extracted from the central valley of [la Californie] in recent years the level has dropped by tens of meters. It is not a year of good rain that will recharge the water tables.
Alexis Maximilien Berg, Assistant Professor in the Department of Geography at the University of Montreal
Recent rains have failed to raise the level of the Colorado River, which remains desperately low, as The Press reported it on 1er February 20232. Levels of the two largest reservoirs in this river, Lakes Mead, in Nevada east of Las Vegas, and Powell, on the Utah-Arizona border, have risen a little over the past few years. last weeks. But they remain far from the average.
The importance of Lake Mead
Created on the Colorado River by the construction of the Hoover Dam, the artificial Lake Mead constitutes, when filled, the largest reservoir of drinking water in the United States. It serves some 20 million people in Arizona, Nevada and California. At maximum capacity, its water level is 375 meters above sea level.
“Sometimes atmospheric rivers, after pouring most of their water over California, also leave water in Colorado basins. But not this time. The drought continues,” observes Amir Aghakouchak.
PHOTO JOHN LOCHER, ASSOCIATED PRESS ARCHIVES
Aerial view of Lake Mead, March 6
“If nothing is done, Lakes Mead and Powell could become what are called ‘dead pools’,” says Alexis Maximilien Berg. Initially, the power stations of the dams will no longer be able to produce electricity. In a second step, the water will no longer come out of them. »
The river’s water level is so low that the seven states that partly depend on it have been ordered by the federal government to come up with a plan to reduce their consumption – it was to be presented no later than January 31. However, there was no agreement because California, the largest consumer, refuses to join the agreement signed by the six other states. The project is still on hold.
With The Canadian Press and East Bay Times
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- 28.7%
- As of March 27, Lake Mead was at 28.7% of its maximum capacity.
source: lake mead water database