Up to 900 junior water rights holders in the Eastern Snake Plain Aquifer (ESPA) could be subject to water curtailments under a new methodology order by the Idaho Department of Water Resources (IDWR) despite a healthy snowpack this year.
The ESPA encompasses nearly 10,800 square miles of the southeastern portion of the state. According to the ESPA Comprehensive Aquifer Management Plan, there are roughly 2.1 million irrigated acres (60% of the state’s total) in the region, which produces 21% of all goods and services, totaling $10 billion. Of the 2.1 million irrigated acres, 871,000 acres are irrigated from surface water, 889,000 acres are irrigated from groundwater and 348,000 acres are irrigated from both sources.
On April 21, IDWR projected a 75,200 acre-foot (an acre-foot is 325,851 gallons) shortfall to the senior priority surface water users’ water supplies during the irrigation season. The new methodology will affect junior groundwater rights holders after Dec. 30, 1953, who are not protected by an approved mitigation plan.
Currently, there are seven approved mitigation plans for the aquifer that if the water users continue to comply with their plans, they will not need to show how they can mitigate projected water shortfalls, the order said. They include the Idaho Ground Water Appropriators Inc., Southwest Irrigation District, Goose Creek Irrigation District, Coalition of Cities, the Water Mitigation Coalition and A&B Irrigation District.
According to IDWR, the predicted shortfall is based on the April 7 joint forecast by the Bureau of Reclamation and U.S. Army Corps of Engineers of 3.7 million acre-feet of water flow at the Snake River Gage in Heise from April 1 through July 31. The forecast is based on a mountain snowpack and predicted streamflow runoff of 112% of average.
“Even though this has been a remarkable winter and water year for many basins in Idaho, it has not been uniformly great everywhere,” said Mat Weaver, IDWR deputy director, in a statement. “Because of the past two years of drought, very low reservoir storage carryover from last year, uncertainty as to whether the reservoirs will fill, very low soil moisture conditions from last fall and near-normal snowpack in Upper Snake basins, water supply conditions are still resulting in an injury determination at this time.”
IDWR will recalculate the shortfall in early July for senior rights holders and any obligations to junior groundwater rights based on irrigation usage and water supply.
The curtailment notice has been put on hold temporarily for junior rights holders pending a hearing on June 6-10 at the agency’s state office in Boise.
Ag impact
Jennifer Ellis, a fifth-generation rancher in Blackfoot, told the Idaho Capital Sun the uncertainty of prospective water cuts would make it difficult to plan for the irrigation and growing season.
“Farmers and ranchers have to have stability in their operation, and it’s not year-to-year and it’s definitely not month-to-month of whether you have water or not,” Ellis said.
Ellis said she sold most of her land in Bingham County last year due to the uncertainty of a stable water supply.
Cameron Mulrony, executive vice president of the Idaho Cattlemen’s Association, told WLJ while the association does not have an official policy on the curtailments, it is imperative that proper water use and management continue for agriculture production and practices in Idaho.
According to the Post Register, Idaho Lt. Gov. Scott Bedke (R) stated he understands farmers and ranchers are concerned about the potential for water curtailments, but “the good news is that nearly every farmer is covered with the mitigation plan.”
Bedke continued the methodology order needed to be updated as it has been nine years since the last order. Bedke hopes some of the spring runoff can be used to replenish the aquifer.
“You’ve got a lot of snow to melt that’s got to go someplace, and it’s going to come off pretty quick as late as it is,” Bedke said. “There’s going to be issues around flooding and handling all this water. We don’t just want it all to go into the river and leave the state. Let’s use that to recharge our aquifers when we can and retain that water in the state for as long as we can.” — Charles Wallace, WLJ editor
