Growers to have sufficient supply in 2010
Early indications for the 2010 water year point to sufficient water storage and ground water reserves to get irrigators through the upcoming growing season in the Pacific Northwest and in Colorado’s San Luis Valley. Those interviewed cautioned that prognostications this early in the water year, it begins Oct. 1, are given with a grain of salt and the understanding that all could expectations could change should the January thru March snowfall prove to be disastrously short of even average forecasts.
In Idaho the water outlook is good for irrigators, with major storage reservoirs in the Upper Snake River Basin already 67 percent full as of Dec. 4, according to provisional data by the Department of the Interior’s Bureau of Reclamation.
Hal Anderson, division administrator for the Idaho Department of Water Resources, said that last year’s unseasonably cool and wet spring resulted in less water being drawn down with irrigators relying on natural flow for irrigation purposes thereby keeping water in storage
With a storage capacity of 4 million acre feet and an average annual yield of over 9 million acre feet of runoff in the Upper Snake, Anderson believes that irrigators will have sufficient water to draw upon in 2010.
According to Anderson the Bureau of Reclamation is operating the reservoirs differently this year. In the past they have held as much they can and then dumping water in the spring to make room for the runoff. This year the Bureau is consistently releasing between 1500 and 2000 cfs over Milner Dam near Burley, Idaho.
We’re not even into the major accumulation season,” Anderson said. “December, January, February are our biggest months and 80 percent of the major precipitation that we get in this state accumulates between December and March.”
Anderson said that the past two years have been good water years for Idaho, from average to slightly above average but that the Climate Prediction Center issued an El Nino advisory in November. The CPC said that the El Nino could result in above average precipitation in Florida and California with below average precipitation in parts of the Pacific Northwest.
Anderson expressed little concern that the El Nino would have a great impact in Idaho.
“Even if we only end up with 90 percent of average, given our reservoir storage we’ll still be fine,” Anderson said.
The one region of concern for irrigators in Idaho is the Thousand Springs area near Hagerman where the continued decline in some of the springs due to depletion of the Eastern Snake River Plain aquifer has resulted in water calls issued on ground water users by senior water rights holders.
According to Anderson, some springs have continued to decline while others have stabilized and some have shown improvement. He hopes that implementation of the Comprehensive Aquifer Management Plan (CAMP) will result in a recharging of the aquifer.
Over in Washington, Tom Myrum, executive director of the Washington State Water Resources Association, said that the Columbia River Basin is rarely at risk. The CRB water supply comes from the snowpack up in British Columbia, Canada, and the runoff is almost always ample to meet irrigators needs.
Myrum said the early forecast for the Yakima basin is positive with current snowpack over 100 percent, but Myrum tempered his optimism with his concerns for the Yakima Basin in an El Nino year. According to Myrum, the Yakima River depends on the Cascade Mountains for its snowpack. El Nino weather patterns tend to shift the water to the south. Myrum said that January and February in an El Nino year can be very dry, but if December weather patterns prove as positive as November then Yakima irrigators do fine.
“If this year had gotten off really bad, then we’d be sweating,” Myrum said, “but it got off really good, so we have to be pretty positive about that.”
However, Myrum said the Walla Walla basin over in the Blue Mountains is real dry and they are keeping close tabs on the situation there.
Going southeast from Pacific Northwest down to Alamosa, Colo., Steve Vandiver general manager of the Rio Grande Water Conservation District, said that it’s a little too early to begin making predictions for 2010.
“Most of our snow comes in February, March, April. We’re waiting patiently for the snow to start. We certainly haven’t built a snowpack that we’d like to see,” Vandiver said.
Just the same, with last year’s runoff and the autumn moisture Vandiver said the aquifers are in decent shape and the current soil moisture is in “awful good shape, compared to a lot of years,” he said.
“We had a good water year,” said Vandiver describing 2009. “Quantity wise, but it (runoff) sure came off early and fairly quickly. The aquifers are in good condition for the wells and I think we’re set to be in pretty good condition,” he said.
Vandiver estimated that the majority of irrigators are ground water users, that flood irrigation systems are in the minority.
“During the drought of 2002, 2003 and 2004, our aquifers were seriously depleted. We’ve worked very hard with the farmers to make the most efficient use of the water they pump,” Vandiver said. “We’ve been able to recover the aquifer some in that period of time. I would say the aquifers are in decent shape but they need a couple more big years to recharge, to get them back up to what we consider normal operating range,” he said.”