Irrigation water situation improving

Water will still be an issue in many areas in ’08, but overall, it is definitely looking better. The Department of Water Resources (DWR) has increased its allocation of 2008 State Water Project (SWP) water for long-term contractors from 25 percent to 35 percent of requests. In one of the more critical areas, the Bureau of Reclamation announced on February 27, the initial Central Valley Project (CVP) water allocation would be 45 percent for ag contractors both north and south of the Delta. That’s based upon a 90 percent exceedance forecast and is a conservative forecast. There is a 90 percent chance that runoff will be greater than projected.

The situation statewide has improved with winter precipitation, and it’s good news even for growers who are lucky enough to have well water resources.

“The rains have come in low rates over an extended period of time instead of all at once so that is good in terms of filling the soil profile,” says Lowell Zelinski with Precision Ag in Paso Robles.

Adequate rainfall also means fewer problems with salts and other nutrients such as boron. “Excess boron can be a problem,” Zelinski says. “Well water has boron, but rainwater does not. Even though you need a certain amount of boron for plant growth, too much can cause problems.”

Soil moisture monitoring capabilities and targeted irrigation will continue to be an important advantage even though winter rainfall appears to have spared growers from the worst-case scenario of the water crisis.

“Water will be tight everywhere with the smelt issue,” says Corky Roche with Roche Vineyard Consulting in Salinas. “We are dealing with cutbacks in most areas. The groundwater situation may improve with all the rains. The profile is at field capacity - a very good thing, so we can hold off on spring irrigations. No winter irrigations were needed in most areas.”

In the northern areas, the situation is similar – okay, but still with issues.

“We are likely below average for rainfall in many areas of the county, but the soils have fully recharged,” says Nick Frey, president of the Sonoma County Winegrape Commission. “For instance, I received 24 inches of rain this year and that is the north side of Santa Rosa. I would think reservoirs are full going into spring. The key issue is Lake Mendocino. It was not full before the last rains, due in part to releases to test some new power generation equipment. Low levels there could impact the Russian River system as occurred last season.”

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