Capital Press

BELLEVUE, Idaho — Blaine County well irrigators plan to form groundwater districts to better respond to the first water delivery call ever filed against them by senior surface water users.

The call was filed in late February by 63 surface users, drawing from the lower Little Wood River system and the Big Wood River system below Magic Reservoir.

The Idaho Department of Water Resources anticipates serving notice of the call to 450-500 potentially affected groundwater users.

About 190 large agricultural irrigators — farming within the triangle bounded by Bellevue, Picabo and the intersection of U.S.-20 and Idaho State Highway 75 ­ — plan a May election for one groundwater district. Smaller irrigators elsewhere in the county, including large residences, golf courses, small ranches and Sun Valley Ski Resort, will vote on a second district in November.

The agricultural users, who raise mostly alfalfa and barley, draw about 500 cubic feet per second of water, about two-thirds more water than users in the other planned district, said Pat McMahon, general manager of the Sun Valley Water and Sewer District.

McMahon said groundwater district fees will be assessed to members based on the volume of their water rights, and those who elect not to participate won’t be covered under any mitigation plan that may be approved to resolve the call.

Idaho’s water laws grant priority to irrigators with the oldest water rights, and surface rights involved in the call predate the earliest wells.

“There’s definitely been some effects on the natural flows from a combination of things,” said Lynn Harmon, Big Wood Canal Co. general manager. “Part is the weather conditions, but a good portion is also depletion of the aquifer from pumping upstream.”

Kevin Lakey, watermaster for Water District 37, which includes both the groundwater users and surface users, said springs flows into the system have dipped to record lows recently, and many surface irrigators had to lease Snake River water to finish their crops last season.

“The most senior decrees on the Little Wood system usually run through September. Last summer, they went off on July 19,” Lakey said.

Magic Reservoir, which provides the only storage in the system, now contains 66,000 acre feet, compared with a capacity of 191,500 acre feet, and snowpack in the surrounding mountains is 82 percent of normal, with little low-elevation snow.

“It is going to be difficult to find significant mitigation in the form of water if mitigation in the Big Wood is required,” said attorney Al Barker, who represents agricultural groundwater users. “There’s not going to be a quick and easy answer.”

IDWR Deputy Director Mat Weaver said a status conference on the call will likely be scheduled for early May, but he doesn’t anticipate much progress until the department completes a water model under development for the system. The model will be similar to one recently updated for Eastern Snake Plain Aquifer calculations.

Weaver said it’s also possible modeling will show ESPA wells near the injured surface irrigators are hydrologically connected and could be subject to the call.

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