Canyon Creek Recharge Facilities
Canyon Creek flows onto the Mountain Home Plateau from the Danskin Mountains, north and northwest of Mountain Home, where all flows are typically diverted by the Mountain Home Irrigation District for filling Mountain Home Reservoir and for direct irrigation use.
During times of heavy runoff, typically in February, March, or early April, the creek flow exceeds the capacity of the Irrigation District system and water flows past the diversion eventually reaching the Snake River a few miles upstream of CJ Strike Dam.
For many years, water has been diverted into gravel pits north of I84 near Mountain Home for recharge purposes.
Water infiltrates through the gravel to recharge the aquifer. The capacity of the gravel pit diversion facilities has been a limiting factor.
In the winter of 2018-19, Elmore County improved the recharge diversion facilities using funding from an Idaho Water Resource Board grant.
Three diversions systems are utilized (Ireland, BLM/ITD, and Simplot), each with headgates and measurement weirs.
The County conducts water quality monitoring under an IDEQ-approved monitoring plan.
2017 recharge activities (prior to improvements to diversion systems by the County) are documented in this IDWR Technical Report.
2019 recharge activities (following 2018-19 improvements).
Mountain Home Air Force Base Project
Mountain Home Air Force Base (MHAFB) obtains its water supply from deep wells.
Due to declining aquifer water levels, the Air Force has determined that the water supply is unsustainable and must be replaced for MHAFB to remain viable.
The State of Idaho, in cooperation with the Air Force, is working toward a Snake River supply for the Base. Current plans call for the Idaho Water Resource Board fund and construct a pump station at CJ Strike Reservoir and a pipeline that will extend down Strike Dam Cutoff Road and State Highway.
The Air Force will fund and construct a water treatment plant at MHAFB. The State has purchased senior-priority Snake River water rights that will be modified for municipal use at MHAFB.
On July 23, 2021, the Idaho Water Resource Board voted to formally recognize the Mountain Home Air Force Base water supply project as one of the highest priority water projects in the State of Idaho.
Mountain Home Air Force Base Sustainable Water Supply Project – Idaho Department of Water Resources
Idaho Water Resource Board approves priorities for allocating $70M in major water infrastructure projects statewide | March 22, 2021
Anderson Ranch Dam Raise
The Idaho Water Resource Board and the US Bureau of Reclamation are proposing a joint project to raise Anderson Ranch Dam by approximately 6 feet to create 29,000 feet of additional storage space.
Elmore County is seeking 10,000 acre feet of this space for future use in the vicinity of Mountain Home.
The project is currently undergoing further design work and environmental compliance (NEPA) reviews.
On July 23, 2021, the Idaho Water Resource Board voted to formally recognize the Anderson Dam raise project as one of the highest priority water projects in the State of Idaho. On November 19, 2021, the Board and Reclamation signed a contract governing the completion and funding of the project.
Cost share agreement between the IWRB and BOR.
Idaho Water Resource Board and Bureau of Reclamation to work on project design as next step for 6-foot raise of Anderson Ranch Dam
Idaho Water Resource Board takes key steps toward raising Anderson Ranch Dam to create additional storage water
Idaho Water Resource Board approves priorities for allocating $70M in major water infrastructure projects statewide
March 5, 2021 update Boise River Feasibility Study and Anderson Ranch Dam Raise
Boise River Basin Feasibility Study (idaho.gov)
Anderson Ranch Pump Station and Pipeline
Elmore County, with cooperation from Mountain Home Irrigation District, is moving ahead with design and permitting of a pump station and pipeline from Anderson Ranch Reservoir to Little Camas Reservoir.
The pump station will divert water authorized under the County’s 200 cfs water right permit 63-34348.
The pump station would also be available to pump stored water from Anderson Ranch Reservoir in the event that county receives storage space from the Anderson Ranch dam raise project.
Water delivered into Little Camas Reservoir can be conveyed through the Mountain Home Irrigation District system to the Mountain Home area for aquifer recharge and supplemental irrigation purposes.
2020-05-01 application package
Order on Reconsideration; Amended Preliminary Order Approving Permit Upon Conditions in the Matter of Application for Permit 63-34348 in the Name of Elmore County, Board of County Commissioners | May 7, 2019 (idaho.gov)
Elmore County Water Rights
Elmore County holds the following water rights.
61-7731. Water right license 61-7731 authorizes diversion from Canyon Creek of 22.68 cfs and up to 962 acre feet annually for groundwater recharge.
61-12314. Permit 61-12314 authorizes diversion of up to 200 cfs from Canyon Creek for ground water recharge.
63-34348. Permit 63-34348 authorizes diversion of up to 200 cfs from the South Fork Boise River for ground water recharge and supplemental irrigation.
02-10535. Application 02-10535 seeks 20 cfs of Snake River water for municipal and ground water recharge purposes.
Treasure Valley Aquifer Model
Elmore County has petitioned the Idaho Water Resource Board to expand the Treasure Valley Ground-Water Flow Model to include the Mountain Home Plateau Aquifer.
As a result, the Board has requested that Idaho Department of Water Resources staff begin the process of data collection to support the modeling effort and to coordinate with the U.S. Geological Survey. Data collection is expected to take approximately three years, and model development is expected to begin in 2025.
On July 23, 2021, the Idaho Water Resource Board voted to formally recognize the Mountain Home Aquifer water supply as a Tier 2 priority water project within the State of Idaho.
Elmore County Request to Expand the Treasure Valley Groundwater Model to the Moutain Home Plateau
Letters Supporting Elmore County’s Water Development Efforts
A Groundwater-Flow Model for the Treasure Valley and Surrounding Area, Southwestern Idaho
Snake River Pipeline Project
On March 3, 2017, Elmore County filed an application to divert 20 cfs of water from the Snake River. The water would be pumped from the river and piped to the Mountain Home area for groundwater recharge and municipal use and irrigation within the Mountain Home Irrigation District.
All of the formal protests to the application have now been resolved. The application is currently being evaluated by the Idaho Department of Water Resources.
