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.
If that occurs, inflow this water year to New Melones Reservoir will be below 600,000 acre feet that SSJID shares with the Oakdale Irrigation District. If that occurs, SSJID will be forced to dip into their conservation account at New Melones which is rarely needed. Should that happen it could trigger the imposing of water allocations.
“We’re starting to look at the ‘D’ word that nobody wants to talk about,” said SSJID General Manager Peter Rietkerk.
As of March 1, precipitation in the Central Sierra that feeds the Stanislaus, Tuolumne, and Merced rivers that supply water for farms and cities in the Northern San Joaquin Valley is at 57 percent of normal. Last year precipitation was 61 percent of normal.
If the trend continues and there are two back-to-back dry years the district would be facing drought conditions in terms of water supplies for at least the balance of the year.
March is typically the last big month of the water year for snow and rain. It is why the state Department of Water Resources uses the snowpack readings on April 1 as the basis for their water deliveries to farms and cities.
The board last week debated whether to start the season with reduced water allocations.
Instead they elected to start with full allocation and to urge growers to watch how they use water. The district meanwhile will be scrutinizing its operations even closer to make sure no water is wasted.
“We’re definitely a little nervous,” Rietkerk said.
There is a weak storm system forecast for this weekend. Other than that, the current outlook for March is dry.
Rietkerk noted allocation limits may be imposed as the irrigation season unfolds.
The conditions in the Central Sierra that SSJID and OID rely on are actually better than other segments of the state as well as snowpack elsewhere. The three river basins serving the Northern San Joaquin Valley are in moderate drought. The southern and northern Sierra are in severe drought while the Cascades that fill the state’s largest reservoir that can hold 4.5 million acre feet behind Shasta Dam is split between severe and extreme drought.
The United States Department of Agriculture drought monitoring effort as of Feb. 25 placed 99.3 percent of the state as being abnormally dry or worst, 84.88 percent in moderate drought or worse, 56.98 percent in severe drought or worse, 29.54 percent in extreme drought or worse and 3.75 percent in exceptional drought.
There are an estimated 26.9 million of the state’s 40 million residents living in drought areas. That includes all of San Joaquin and Stanislaus counties. All of Stanislaus is experiencing moderate drought while will all but a sliver of San Joaquin County is in severe drought. The non-severe drought area is along the eastern county line and is classified as being in moderate drought.
The current drought conditions currently aren’t triggering a statewide emergency declaration given the shortfall could end up being reduced drastically this month and in April. But if it doesn’t happen, the odds of enough precipitation after May 1 to steer the state away from drought are essentially nil as both snow and rain in any measureable amounts becomes a rare occurrence in California from May to October.
That means the deficits for California’s water needs will have to be drawn from existing storage.
It is why releases have been cut back at various reservoirs.
To contact Dennis Wyatt, email email@example.com