It may be gloomy and cold but it isn’t wet.
January has turned into drier than normal.
Based on the current trend that means normal water demand this year will be covered with just a little room to spare.
While conditions are not raising the specter of a drought at the moment given a couple of major cold wet storms would pad the state’s largest reservoir by far — the Sierra snowpack supplies 30 percent of California’s water needs — if one of those storms is a Pineapple Express bringing warm rain to melt snowpack prematurely or the dry weather continues the Golden State’s water cushion will become anemic.
“It’s a drier than normal January,” noted South San Joaquin Irrigation District General Manager Peter Rietkerk.
Based on a conservative projection used by the Department of Water Resources with the snowpack as of Jan. 15 within the Stanislaus River watershed, the runoff is expected to be 620,000 acre feet — or 20,000 acre feet more than the 600,000 acre foot of water inflow into New Melones Reservoir that is split 50-50 between SSJID and Oakdale Irrigation District.
Overall the Central Sierra snowpack is 70 percent of normal for this month and 48 percent of normal of average for the critical April 1 date that is used to mark the historic end of winter storms.
Rietkerk noted the Bureau of Reclamation — the operators of New Melones Reservoir that is the linchpin of water storage oh the Stanislaus River watershed — are doing their best to mimic natural flows from storms this year in a bid to keep adequate water in storage in the event the dry trend continues while not having too much in case a Pineapple Express passes through the Sierra bringing warm rain to trigger a premature and rapid snow melt creating flood concerns.
“They’ve got a tough job,” Rietkerk said of the Bureau.
Flows from New Melones was at 668 cubic feet per second — the volume of water that 668 basketballs passing a specific point in one second can hold — is a tad higher than normal. That’s because during the salmon spawning season fish got higher up the Stanislaus than normal. The higher flows will make sure they do not get stranded.
The current inflow to the 2.4 million acre foot reservoir is 790 cubic feet per second. As of Sunday reservoir capacity was holding 1,982,470 acre feet of water or 141 percent of average for Jan. 19.
Why those numbers are meaningful to farmers as well as Manteca, Lathrop and Tracy residents is their reliance on SSJID water. In Manteca’s case almost all of its winter use comes from the Stanislaus River while more than half of the spring, summer and fall consumption is provided from the SSJID system.
Due to unpredictable precipitation trends from year to year and the need for carryover storage in case 2021 is a drought year, cities such as Manteca have adopted fairly aggressive water conservation measures to make sure there are adequate supplies not just for the current year but next year as well.
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