Courtesy of Wes Hipke
BOISE — Idaho water users have suspended an effort to increase precipitation from winter storms by seeding clouds with silver iodide to form additional ice nuclei.
The program, led by Idaho Power in cooperation with state irrigators and the Idaho Department of Water Resources, was put on hold Feb. 8 based on the abundant mountain snowpack.
“The water supply all over Southern Idaho is looking really good,” said Brian Sauer, water operations manager with the Bureau of Reclamation. “If there is too much snow, they don’t want to cause any flooding with their cloud seeding operations.”
Idaho Power spokesman Brad Bowlin said it’s likely snowpack may dip below the program’s threshold soon and justify resuming cloud seeding around Island Park and in the Payette Basin.
“I don’t know if we’ve ever stopped across the whole territory. This might be a first,” Bowlin said.
The program incorporates 55 ground-based generators and three aircraft that seed from the sky. Based on current conditions, Bowlin said continuing operations would likely produce no return on investment, as storage water may ultimately be released for flood control.
Bowlin said the program’s suspension is a setback for research funded by the National Science Foundation to better understand the physics of cloud seeding.
However, the hiatus is a good sign for irrigators, who hope to start the season with full reservoirs, despite entering winter with little storage carryover.
“The projections are if we keep getting even a little bit of snow for the next six weeks, I think you’ll have to do some flood control at this point,” said Lyle Swank, watermaster for the water district that includes the Upper Snake reservoir system.
Swank emphasized flood control releases aren’t an exact science, and reservoirs don’t always refill after space is freed.
Wes Hipke, IDWR’s recharge program coordinator, has already started making contracts with canal managers, anticipating he’ll get to test new infrastructure the department helped finance to conduct managed aquifer recharge in the Upper Snake. Recharge involves injecting surface water into the aquifer through unlined canals or spill basins to replenish declining groundwater levels.
Water rights for Upper Snake recharge are only in priority during spring flood-control releases. Hipke said IDWR has the capacity to recharge up to 430 cubic feet per second of water in the Upper Snake, which equals 25,000 acre-feet over the course of a month.
A recharge water right in the Lower Snake remains in priority throughout winter, but Hipke said the department has fallen well short of its Lower Valley goal, recharging 43,450 acre-feet thus far. He said ice in the Northside Canal has reduced the program’s recharge capacity since early December, but he’s optimistic the ice will soon be cleared and the Lower Valley program will reach 80,000 acre-feet before winter’s end.