Recharge Plans Gain Momentumby Julie Pence
Times-News, November 20, 2004
TWIN FALLS -- The amount of water available to Twin Falls from its main water source, the Blue Lakes spring on the north side of the Snake River Canyon, has dropped some 30 percent during the past 50 years.
The decrease has accelerated during the past five years.
Part of the reduction is due to changes in irrigation practices and also to increased groundwater pumping on the north side of the Snake River. A University of Idaho hydrologist from the Idaho Water Resources Research Institute said this week those draws on the Eastern Snake River Plain Aquifer are fairly predictable now. But if the five-year drought continues, hydrologist Donna Cosgrove said it will continue to reduce the amount of water available to spring sources such as the Blue lakes spring.
One way to help replenish the water is through managed recharge. In fact, part of the solution to replacing between 600,000 and 900,000 acre feet of water in the aquifer involves adding 200,000 acre feet of managed recharge, said Clive Strong, who heads the natural resources division of the state attorney general's office.
"Recharge has got to be part of our plan," added Rep. Dell Raybould, R-Rexburg, the co-chairman of a special interim legislative water committee tackling the problem. "In excess years like '97, instead of it going to the ocean, we've got to put it back into the aquifer."
A site about 10 miles north of Eden, referred to as Milepost 31, has the potential to deliver some water to the Blue Lakes spring. But no study has been completed that quantifies how much water would wind its way there, said local hydrologist Chuck Brockway.
Nonetheless, the site has potential to accommodate a huge amount of water, said David Blew, who manages recharge issues for the Idaho Department of Water Resources. The site can accommodate up to 500 acre feet a day. That is enough water to cover 500 acres with one foot of water.
But there would not be that much water soaking the site on a daily basis year round.
"You've got to remember you can only run early spring and late fall," Blew said.
Those are the times when water in the canals that is not being used for irrigation could be diverted to the site. In addition, no one knows for sure when that water would make it to the Blue Lakes source.
Cosgrove has recently completed a model that will provide more information on how recharge efforts will affect all spring users along the rim of the Snake River Canyon, though it hasn't been released yet.
Blew said infrastructure to get water to the Milepost 31 site would cost about $500,000. There would be yearly maintenance costs, too. For seven Magic Valley sites north of the Snake River, including the Milepost 31 site, the yearly cost for maintenance would initially run at about $700,000, he said.
Trying to get Milepost 31 up and running, however, has stretched into a painfully long process. People have been looking at the site for about 10 years, Blew said. Interested parties have encountered all kinds of hurdles. One includes working out agreements with Idaho Power Co. in regard to satisfying its senior water rights in the Snake River system. Another involves working with the Bureau of Reclamation, which operates federal dams and owns some of the canals. An yet another has been satisfying environmental and administrative concerns on the Bureau of Land Management site, Blew said.
To top off the problems, trying to find the funding for the recharge sites could be a challenge, he added.
"This is a long and drawn-out process, and there are a lot of agencies involved," Blew said.
And even if all the hurdles are eventually cleared, the recharge effort won't be something the population of south-central Idaho can depend upon every year. In the high-water year of 1997, there could have been up to 320,000-acre feet added to the aquifer if recharge sites had been up and running. On the other hand, there has been no water available for recharge during the past two years, Blew said.
Based upon studies from 1982 through 2001, there would be on average about 170,000 acre feet each year that could be added to the seven Magic Valley sites identified as good places to restore water to spring users.
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