Idaho's intensively reformulated and recalibrated computer model of the Eastern Snake River Plain Aquifer will become a key tool for water managers and lawmakers as they struggle to come to grips with water shortages in the vast underground reservoir.
The model is "probably the best tool we could have developed to do what we need to do," said Idaho Department of Water Resources Director Karl Dreher in the University of Idaho's Feb. 2 issue of AgKnowledge.
When the water model is combined with an economic study, which is due at the Legislature this week, lawmakers will have the basis for beginning to look at solutions to water conundrums associated with the Eastern Snake Plain Aquifer, said Senate Minority Leader Clint Stennett, D-Ketchum.
"The model for the groundwater coupled with the economic information are the two tools we will use to form the basis for a compromise or a settlement," Stennett said. "The water model alone won't provide a political solution. Somewhere in between is the answer."
Based on 22 years of data, the Water Resources Department's aquifer model allows its users to evaluate the connections between Idaho's groundwater use and surface-water supplies.
"We've tried to wring every last drop out of the data, and I think we've done a pretty good job," said Donna Cosgrove, University of Idaho assistant professor of biological and agricultural engineering.
Cosgrove was quoted in AgKnowledge, which is produced by university professors and distributed via e-mail to lawmakers and others throughout Idaho.
Cosgrove is one of three water researchers from the university's Idaho Water Resources Research Institute who worked for almost four years to rework the model.
A legislative subcommittee appointed by Gov. Dirk Kempthorne is using the model to run scenarios of potential water-use practices and policies.
When researchers ran the scenario of maintaining the status quo for the next 22 years, the model showed that aquifer outflows exceeded inflows by about 180,000 acre feet each year. Although the amount appears relatively small, the difference is cumulative, and effects would accelerate during periods of drought.
"Will we see continual decline if drought continues? You bet we will," Cosgrove said.
Future analyses will project the effects of managed recharge, continuous conversion to sprinkler systems and continued drought.
"We can't turn the clock back," Cosgrove said. "We need to look for sound aquifer management practices."
The discussion is important because the Snake River Plain's economy is closely tied to water, and the legislature's solutions will have a direct effect on dollar figures.
Last fall, University of Idaho Extension educators Bill Hazen and Bob Ohlensehlen studied the fiscal impacts of water use for six Magic Valley counties. They found that 4.9 million acre feet of water produced $1.9 billion in crops, livestock and processed food products. That translated into $387 for every acre-foot of water.
Crunching the numbers a little further, they found that 288-acre feet of water support one job in agricultural production or processing. Altogether, they said every 120-acre feet of water used in the six-county area for agricultural production and processing creates a job somewhere in the Magic Valley economy.
Idaho lawmakers are wrestling this winter to come to grips with aquifer water shortages, which have been accentuated by five years of drought.
Alan Merritt, a regional manager with the Idaho Department of Water Resources, said a yearlong dispute between Hagerman Valley fish farmers and Snake River Plain groundwater pumpers instigated the ongoing investigation.
Merritt pointed out that spring levels, which rise from the underground aquifer near Hagerman, have been aided by surface irrigation on the plain and peaked in the 1950s. Since then, development of groundwater pumping irrigation systems on the plain—among a myriad of other causes including drought, adjustments in canal operations and more efficient pumping—has diminished the amount of water issuing from the Hagerman area springs.
In response to the problem, the state's chief water manager on Feb. 25, 2004, ordered Magic Valley wells on the north side of the Snake River shut down unless water users could come up with replacement water for a Hagerman-area fish hatchery that is suffering water shortages. The shutdown was scheduled to apply to wells developed after July 13, 1962.
Idaho Department of Water Resources Director Karl Dreher's order would have affected groundwater users in Water District 130, which runs from Gooding and Minidoka counties into Lincoln County.
The premise of the decision lies with the interconnected nature of the Snake River Plain aquifer and the rivers and springs that feed and rise from it.
The problem is that ground water has been depleted to the point that it is detracting from springs in the Hagerman valley, where parts of the aquifer have historically dumped into the Snake River. Several Hagerman fish hatchery operators filed with the Department of Water Resources last year because the water they draw from springs had been diminished.
A call by Rangen Inc., a fish farm with the most senior water rights of those who made a "call" for water, took center stage. Rangin's water right priority, July 13, 1962, is the date Dreher used as the proposed cutoff for the plain's irrigators.
But before ground water pumping was curtailed this spring, the state of Idaho entered into an agreement with the Magic Valley Ground Water District, the North Snake Ground Water District and spring users in the Thousand Springs reach of the Snake River. The temporary solution the groups reached was to pump water and money into the Hagerman area this year and to continue looking for long-term solutions. As another part of the solution, an interim legislative committee is performing an ongoing search for solutions.
The search for water solutions will likely be one of the defining issues of this year's legislative session.
But Stennett did not sound overly optimistic that a long-term solution will be cemented this year.
"Every day it seems like it's farther and farther away for this year," he said. "I don't think there's going to be a final settlement for this year."
