California has seen big changes in reservoir levels so far this rainy season and the trend is up for the foreseeable future.
At the beginning of the water year for 2020-2021, some major reservoirs, such as Lake Oroville, were at record lows. California’s well-known reliance on water capture and transport was under severe strain until a record October storm provided quick relief.
More precipitation has fallen on California during its current “water year” than in the full prior 12-month span, the National Weather Service says.
The downpours and mountain storms of recent weeks have helped boost the state’s precipitation volume to 33.9 trillion gallons thus far for the water year that began Oct. 1, compared to the previous water year’s 33.6 trillion gallons, the service said Sunday. Lake Tahoe by comparison contains roughly 40 trillion gallons.
California is likely to emerge from the winter with little relief from drought, federal climate experts said Thursday, setting the stage for a third year of dry weather and continuing water shortages. The monthly climate report from the National Oceanic and Atmospheric Administration projects that drought conditions will persist in almost all of California through February. With the next three months historically the state’s wettest, the opportunity for drought recovery is essentially lost.
The current ongoing two-year dry period in California, punctuated by the third-driest water year on record for the Central Sierra, is part of California’s overall arid fate so far in the 21st century, according to the state Department of Water Resources.
The Golden State’s hydrology now increasingly resembles conditions in the Colorado River Basin this century, where multiple, consecutive, drier-than-average years are mixed with an occasional wet year. California’s last wet water year was 2016-2017, the second-wettest on record.
How dry? The region received a little more than a third of normal precipitation from Oct. 1, 2020, to Sept. 30, 2021, according to data from the National Weather Service — a common occurrence for the past several years, which bodes ill for a region already at the worst “exceptional” level on the U.S. Drought Monitor map.
After two dry years, the California is in desperate need of rain and snow. October marks the beginning of California’s new water year, which will run through Sept. 30 next year.
This also signals the transition from the long, dry summer months to the wetter time of year. But new research is showing a delay to California’s rainy season.
With just one month left in the precipitation year and little rainfall to show for it, Turlock Irrigation District and its customers are currently experiencing the fourth-driest year on record.
According to TID hydrologist Olivia Cramer, the Tuolumne River Watershed has received just 18.23 inches of precipitation since Sept. 1, or just about half of the historical average. The TID precipitation year, which is different from the water year, runs from Sept. 1 through Aug. 31 and will come to an end next month. The water year runs from Oct. 1 through Sept. 30.
This year’s 18.23 inches of rainfall come as the region experiences a second-straight year of drought conditions and puts 2020-2021 in the record books as TID’s fourth-driest precipitation year on record. The three driest years on record in order are 1977 (10.90 inches), 1976 (17.46 inches) and 2015 (17.50 inches).
A disappointingly dry February is fanning fears of another severe drought in California, and cities and farms are bracing for problems. In many places, including parts of the Bay Area, water users are already being asked to cut back.
The South San Joaquin Irrigation District season is starting March 10 although board members added an asterisk to that decision. Restrictions on water allocation as the irrigation season unfolds loom as a possibility especially if March ends up being mostly dry. The board last week was guided by the conservative outlook the National Oceanic and Atmospheric Administration posted for its California and Nevada River Forecast that includes the Stanislaus River watershed that the SSJID relies on to make deliveries to farmers irrigating 52,000 acres around Manteca, Ripon, and Escalon as well as deliver drinking water to Manteca, Lathrop, and Tracy.
