Precipitation at Beardsley Reservoir at the 3,400-foot elevation on the Stanislaus River is typically one of the best indicators of how water supplies will shape up to carry the South San Joaquin Irrigation and the 52,000 farm acres and three cities it serves through the summer and fall.
Based on reading as of Feb. 1 at the mid-point of the water year 22 inches have been recorded at Beardsley that is operated jointly by the Oakdale Irrigation District and SSJID through the Tri-Dam Project.
That’s 60 percent of what accumulates at Beardsley for an entire water year. In a normal year that would be a solid number. But given how fickle Mother Nature can be as demonstrated by the massive December snowfall that set records in some parts of the Sierra that was followed by a dry January that sent water content of the snow from above historic averages to below historic averages, 60 percent of a 12-month average at the water year’s midpoint far from eases concerns.
“The warm spell in January and now into February is evaporating water off the surface of the Sierra snowpack,” noted SSJID General Manager Peter Rietkerk.
With the forecast calling for drying winds, temperatures heading toward the 70s (the forecast anticipates a high of 69 degrees on Monday), and no rain or snow in the near future the situation for water supplies is precarious.
Rietkerk noted if several atmospheric rivers before April 1 that could reduce the odds of the current year being significantly below average in terms of yields for water supplies.
“The December (storms) put the state in a better position than we were last year at this time,” Rietkerk pointed out.
The SSJID board next week is expected to discuss the start date for the 2022 irrigation season.
Rietkerk noted moisture content of heavier ground near Escalon is OK but the sandy soils south of Manteca and near Ripon are starting to show duress with moisture content starting a foot down.
As of Thursday the United States Department of Agriculture has 66.39 percent of California in severe drought including the entire Central Valley, the Bay Area, and the Central and Southern Sierra.
At the start of the water year on Oct. 1 over 93 percent of California was in severe drought. A year ago it was at 58.4 percent.
If SSJID at any point needs to reduce water deliveries due to water supply shortfall the pain is shared equally by irrigation customers and the cities of Manteca, Lathrop, and Tracy.
Based on current conditions the Stanislaus River watershed is expected to yield just less than 600,000 acre feet of water that is required to satisfy the superior water rights of SSJID and OID before other users.
To contact Dennis Wyatt, email dwyatt@mantecabulletin.com
