Is the drought over after the Storm of the Decade?
It may be for 40 percent plus of California as declared Thursday by federal drought monitors but not in the Stanislaus River watershed that Manteca, Lathrop and Tracy residents rely on as well as farmers in Manteca, Ripon, Escalon, and Oakdale.
New Melones — the state’s fourth largest reservoir— was at an anemic 34% of capacity and 59 percent of average while Shasta Lake was at a robust 82 percent of capacity and 129 percent of average.
While virtually every other reservoir in the Sierra ramped up flood releases this past week, New Melones didn’t. That allowed the Bureau of Reclamation to capture most of the 180,000 acre feet of water — enough to cover all of San Francisco with almost six inches of water — that flowed into New Melones this past week.
“New Melones had the capacity because (the watershed) was hit so hard by the drought,” said South San Joaquin Irrigation District General Manager Peter Rietkerk.
Rietkerk noted the drought — just like the Pineapple Express storm systems that just slammed California — has impacted various watersheds throughout the state differently.
The uptick in Stanislaus River flows through Ripon was the result of local run-off as well as releases from the Tri-Dam Project’s Tulloch Reservoir operated jointly by SSJID and Oakdale Irrigation District.
The Stanislaus River, besides the usual winter flow that it carries from New Melones, also brought local storm runoff into Tulloch. Rietkerk said flows from Tulloch are down to 2,700 cubic feet per second — the equivalent of 2,700 basketballs rolling past a point in a given second — after being ramped up sustainably from the normal January flow of 1,500 cubic feet of water a week ago.
The Tri-Dam Project reservoirs above New Melones are holding significantly more water than normal for this time of year. Donnells with a capacity of 64,320 acre feet is at 50,239 acre feet or 78 percent of capacity and 272 percent of normal for mid-January. Beardsley with a capacity of 97,800 acre feet is at 79,104 acre feet or 81 percent of capacity and 195 percent of normal.
Rietkerk noted the series of storms may allow SSJID to postpone the start of the irrigation season making more water available in the critical months of late summer and early fall.
“It is too early to make any call on water supplies,” Rietkerk said.
The April 1 snowpack survey is the linchpin for water deliveries. In past years of the drought when January was strong snow fell off in the following three months.
SSJID and OID are also facing a state push to commandeer more water for fish that would also impact irrigation and urban water supplies.
As of Jan. 1, the National Weather Service’s Sacramento staff indicated the Central Sierra watershed — that includes the Stanislaus River Basin that Manteca, Lathrop, and Ripon rely on as well as Yosemite National Park — needed 96.53 inches of water by Sept. 30 to completely break the drought’s back.
The region averages 40.8 inches of precipitation based on annual readings at Calaveras Big Trees, Hetch Hetchy, Yosemite National Park headquarters, North Fork in Madera County and Huntington Lake. The weather year started with a 114.05-inch precipitation deficit from the previous five years. Before the current storm system hit, the average rainfall accumulated as measured by the five stations for the first three months of the water year that started Oct. 1 was 17.7 inches.
At this time last year, 97 percent of California was declared to be under drought conditions.
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