The Sonoma County Water Agency is working with grape growers on a nighttime irrigation schedule that would help the agency manage Russian River flows to conserve water.


The Water Agency now provides a cushion of water in the river to cover the needs of growers, who account for a third of the water taken out of the Russian River.

But if growers in places like the Alexander Valley, who hold legal rights to some of the water, aren't irrigating, the water just flows down the Russian River into the ocean.

If the agency knows when the growers plan to turn on their pumps, releases from Lake Mendocino can be tailored to cover the expected need.

"There is potentially 10,000 acre-feet to be saved in Lake Mendocino if everything went perfect," said Chris Murray, the Water Agency's principal engineer. "It could be a really good thing for the reliability of the lake."

That much water, 10,000 acre-feet over the course of the irrigation season, is more than double the 4,000 acre-feet that the Water Agency is being ordered to save in Lake Mendocino this summer.

The Water Agency has been ordered by the state Water Resources Control Board to cut the amount it takes from the Russian River by 15 percent until Oct. 28, with the water saved in Lake Mendocino for the fall salmon run.

As of Sunday, the Water Agency was at 14.2 percent for the first three weeks of the mandatory period through the conservation efforts of its largest contractors, the cities of Santa Rosa, Windsor, Rohnert Park, Cotati, Sonoma and Petaluma and the Valley of the Moon, North Marin and Marin Municipal water districts.

Murray said any savings by an irrigation schedule don't count toward the 15 percent saving the state mandated. But the ability to release less water could ease the situation in future years like this one, when a dry spring and reduced diversions from the Eel River left Lake Mendocino at a low level.

"It is more of a long-term thing," Murray said. "It would take quite a bit of practice to implement it, but by working with people over time, we could get there and see that size of savings. It is very early, it is really preliminary."

Grape grower Dennis Murphy of Murphy Ranch in Geyserville said, "If the water agency does not have to put out extra water to cover the peaks and valleys in demand, they can save water in the long run."

In meetings Tuesday and last Friday, Murphy and other ranchers began talking to Water Agency engineers to find out what they can do to help the conservation effort.

Murphy said that he and at least three other large-scale growers have begun implementing a nighttime irrigation schedule, and he is talking to other growers to do the same.

"We have been encouraging growers to irrigate at night, to flatten this thing out," said Murphy, who has 200 acres on the Alexander Valley floor.

It is estimated that grape growers use about 37,000 acre-feet of Russian River water a year to irrigate their crops, said Bob Anderson of the United Winegrowers.

Anderson said his group also has been urging growers to conserve, in particular by irrigating at night, when there is less loss to evaporation.

"Guys are listening and adopting changes that in the end save them water and save them energy costs," Anderson said. "Everybody's spreading the gospel here to say that there are things that can be done to cut water use, and that is a big one."

You can reach Staff Writer Bob Norberg at 521-5206 or bob.norberg@pressdemocrat .com.