BOISE — Irrigators with storage in Upper Snake River reservoirs worry a recent change in state water policy will decrease the odds that their water rights will fill in future years.
The Water District 1 watermaster has long allowed for a “reset” of storage water right priorities some time between August and early October, depending on water conditions.
According to the state’s historic practice, even in years when reservoirs filled completely and storage irrigators were allocated their full water rights, junior irrigators’ natural-flow rights could be curtailed in late summer or early fall to prioritize replenishing storage for the next season.
Irrigators and representatives from the Shoshone-Bannock Tribes have been negotiating during the past couple of years to identify a reset date to best balance the rights of junior surface-water irrigators with the need to fill reservoirs, but have failed to reach an agreement. On Aug. 18, Milner Irrigation District formally challenged the current reset policy.
In response, Idaho Department of Water Resources Director Gary Spackman sent the district’s watermaster a letter on Oct. 27 ordering that the reset date for this season be moved back to Jan. 1, 2018, reasoning the reservoir storage rights identify a “season of use of Jan. 1 through Dec. 31.”
Spackman’s ruling has been contested and is scheduled for a Nov. 13 preliminary hearing. In his letter, Spackman wrote that the contested case will establish “how the season of use defined by the decrees interacts with a reset date earlier than Jan. 1.”
Even with a Jan. 1 refill date, Water District 1 Program Manager Tony Olenichak explained the state will have the opportunity to capture water that isn’t used for other irrigation rights in the reservoirs, under a Bureau of Reclamation refill right, which was established during the recently completed Snake River Basin Adjudication and is subordinate to all other water rights.
Olenichak said water is abundant this season and will have to be released from reservoirs for flood-control anyway, but addressing the reset issue will be critical for future years.
Aberdeen-Springfield Canal Co. General Manager Steve Howser and Twin Falls Canal Co. General Manager Brian Olmstead would support an Oct. 15 reset date — late enough to avoid curtailing junior natural flow irrigation rights while still allowing time for reservoirs to refill.
Olmstead — whose company is a member of the Surface Water Coalition, an intervenor in the case — agrees the state “shouldn’t take away somebody’s natural flow right to fill a reservoir that’s already been filled.” But he and Howser both believe a Jan. 1 refill date would prioritize water rights for aquifer recharge — injecting surface water into the groundwater to reverse aquifer declines — at the expense of maximizing use of storage infrastructure.
The state must pay fees to canal companies to recharge water, through seepage from their unlined canals and adjacent spill basins, and groundwater eventually flows out of the aquifer.
“I see a big danger of us preferring recharge over storage,” Howser said. “We’ve got to fill the reservoirs first.”