IDAHO FALLS, Idaho — The U.S. Bureau of Reclamation has waived its usual requirement that Palisades Reservoir storage holders shut off their canals throughout winter, which should open new aquifer recharge opportunities for the state.
Under the agency’s Winter Water Savings Program, space-holders are obligated to close their canals for 150 consecutive days following the irrigation season, allowing the reservoir to fill.
However, Upper Snake Reservoirs are entering this winter with far more storage than necessary, following an exceptionally wet water year. Water District 1 officials recently calculated that flows at the Heise gage, located above the Snake River’s first diversion, were the second highest in recorded history — second only to 1997 — during the water year that ended Sept. 30.
The district also estimated its reservoirs have 1 million acre-feet of available space, compared with 1.7 million acre-feet of inflows form the poorest refill on record.
The Bureau will suspend the Winter Water Savings requirement for at least three months. Corey Loveland, an agency official, said usual winter releases from Palisades range from 900 to 1,100 cubic feet per second. Releases have already been heightened from Palisades, and Loveland expects the Bureau to keep them around 3,000 cfs throughout winter.
“We’ll definitely have to move a large amount of water to make room for flood-control space,” Loveland said. “Water will be available to use for recharge (in the Upper Snake Valley) this fall and throughout winter.”
The state has a special water right that remains in priority throughout winter in the Lower Snake — downstream of Minidoka Dam — for aquifer recharge, which involves paying canal companies to run water through their unlined systems or dump it into adjacent spill basins so that it may seep into the aquifer and restore declining groundwater levels.
Wes Hipke, who coordinates the Idaho Department of Water Resources recharge program, has already started recharging 61,000 acre-feet of storage water provided by the Surface Water Coalition. The coalition received the water from junior groundwater users and food processing companies as mitigation for a call, but it won’t be needed this season. The Bureau’s announcement will enable some canal companies to continue recharging the storage water for the state into November, when they’d normally be restricted by Winter Water Savings.
Hipke said he’s also been making calls to find more recharge partners, hoping to expedite recharging of the storage water to free capacity for excess Palisades releases. Factoring in water that won’t be needed because a power turbine isn’t in service at Minidoka Dam, Hipke said the Bureau estimates he should have at least 800 cfs of flood releases available for Upper Valley recharge this fall and winter, though it remains to be seen if he’ll find the capacity to put that much water to good use.
Idaho water officials have asked Congress to approve a permanent policy change that would make it easier for the Bureau to dispense with Winter Water Savings during wet years.
In the meantime, Lynn Tominaga, executive director with Idaho Ground Water Appropriators Inc., believes the extra opportunity to recharge should help the aquifer recover, which is a condition of the water call settlement his members reached. Some of the water recharged this fall will also bolster spring flows months from now, when they’re needed more, he said.
“It’s good for everybody. It helps the groundwater users and the surface users,” Tominaga said.