Study lists storage options for Idaho’s Henrys Fork
By John O’Connell
ISLAND PARK, Idaho — The Bureau of Reclamation has released a draft study outlining a dozen options for increasing storage and better conserving water throughout eastern Idaho’s Henrys Fork Basin.
Public comment will be accepted about the draft through March 6 at www.usbr.gov/pn/programs/studies/idaho/henrysfork/study/index.html. A final version of the basin study, which has been in the works for four years with $400,000 in state funding and a somewhat larger Reclamation match, will be released April 30.
Participants in the study — including Reclamation, Idaho Department of Water Resources and a work group of stakeholders — narrowed down the best possibilities from a list of 51 ideas they identified for addressing water needs in the Henrys Fork. IDWR’s Water Resource Board will rank the options in a separate report to be released this summer.
The Henrys Fork watershed supports 280,000 irrigated acres.
“We’re heading into an era where there’s closer attention being given to intense water usage,” said John Redding spokesman for Reclamation’s Snake River area office.”It now falls to the State of Idaho to decide which way they want to go on a pathways forward.”
Even before the draft study’s release, Gov. Butch Otter announced in his annual State of the State Address plans to move forward with the most cost-effective project identified — expanding Island Park Reservoir’s capacity to accommodate another 30,000 acre feet.
Otter has earmarked nearly $2.5 million for an engineering study on the reservoir expansion. Construction could be completed within five years for an additional $5 million. The added storage would cost about $240 per acre foot. IDWR Planning Division Chief Brian Patton explained Island Park Dam is already tall enough to accommodate the extra storage, and the project would entail installing an inflatable bladder to block the main spillway and making upgrades to an emergency spillway.
Once work is complete on Island Park Dam, Patton said, the state will likely consider a $28 million expansion of Ashton Dam, which would create 20,000 acre feet of storage at a cost of $1,382 per acre foot. Patton said rebuilding the Teton Dam, which was located on the Teton River, a Henrys Fork tributary, will remain a top option for long-range development and could be completed for $1,900 per acre foot.
The report acknowledges options to construct new dams — proposed on the Teton River, Upper Badger Creek, Moody Creek and Spring Creek — don’t have broad stakeholder support given current “social, cultural and environmental issues.”
Patton explained the study’s non-storage options, such as managed aquifer recharge, water markets, irrigation canal piping, demand reduction programs and canal automation, have broad support among stakeholders. However, Patton said the state is already pursuing most non-storage options, except for improved automation of canal systems, which the study estimates would conserve water at a cost of $941 per acre foot.
“It’s certainly something we would support with loan dollars if the users want to go in that direction,” Patton said.