OAKLEY — A watchful eye and proactive measures this spring and summer kept Lower Goose Creek Reservoir from gushing over the Oakley dam spillway and flooding everything on its natural path to the Snake River, including the city of Burley.
And the scare prompted changes that could lessen the risk in future years.
A high snowpack above the reservoir had officials on edge as they watched the rate of mountain snowmelt this spring. Many of them remembered a near-disaster in 1984 that took a whole community to build an emergency canal to the river to divert the potential floodwater around Burley.
OAKLEY — In the early spring of 1984, Rex Gerratt stared at the pegs he’d stuck into the cla…
The amount of water flowing into the reservoir this year prompted canal officials to divert about 20,000 acre-feet of water.
If the water had not been released, would it have topped the spillway?
“That’s not a very nice question to ask,” said James Mullen, watermaster for Oakley Canal Co. “There is a good chance it would have gone over if we hadn’t diverted it.”
Some of the water was injected into the aquifer, and some was released through a diversion canal that empties into Murtaugh Lake, said George Warrell, Cassia County undersheriff and emergency management coordinator.
“The majority of it went back into the aquifer,” Mullen said. And that helps keep the precious irrigation water in the area and the aquifer healthy.
The water is put back into the aquifer through “sink trenches” northeast of Big Cottonwood Wildlife Management Area, and one more trench was added this year.
“There are four now, and we feel really good about that,” Mullen said. “There is a place for the water to go.”
The county’s All Hazards Mitigation Plan now states upgrades needed at the dam to manage high-water years; they include more injection sites and a venting system at the dam so water can be released more quickly during an emergency.
“The canal company,” Warrell said, “did a really good job of managing the water and keeping downstream folks safe this year.”