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SFBR Diversion Project

The Aquifer 

Simply put, aquifers are layers and areas of rocks below ground where all the cracks, crevices, and spaces between rock particles are full of water. The water is able to move through aquifers and people drill wells into them and pull the water out to use for their own uses.

100% of the drinkable water in Elmore County
comes from the ground.

Groundwater levels within the regional aquifer have been declining for more than 60 years, the fallout of over-allocated groundwater resources. The Idaho Department of Water Resources recognized this situation with declaration of the Cinder Cone Butte Critical Groundwater Area in 1981 and the Mountain Home Ground Water Management Area in 1982. Although, after those declarations, groundwater levels have continued to fall, with no real action taken to improve groundwater condition. This is until the more recent joint efforts of Elmore County and the Idaho Water Resource Board (IWRB). In some areas, the water table has fallen 100 feet or more. Multiple studies are available to review, they are listed here.

Quick Facts
  • Cinder Cone Butte area is declining up to 5 feet per year.

  • South side of the City of Mountain Home declining approximately 3 feet per year.

  • Declines at the Mountain Home Air Force Base approximately 1.5 feet per year.

  • East of the Air Force Base is declining approximately 2 feet per year.

Source: SPF Water Engineering, 2017

Water is Life 

There is no more important resource for a healthy, vibrant community than clean drinking water. Our families, schools, and businesses rely on having water. The long-standing lack of water has driven multiple businesses away from Elmore County in the last decade and continues to be an economic hurdle. Elmore County is unique by being home to the Mountain Home Air Force Base, which contributes $800 million annually to Elmore County's economy and $1 billion annually to Idaho's economy. Not only does the base support Elmore County, Elmore County supports the base with civilian staff and off-base resources. The Air Force Base relies on groundwater to support its operations. The State of Idaho and the U.S. Air Force are currently working jointly on a project to bring surface water from the Snake River to a new surface water treatment plant at the Air Force Base. The cost of the State-funded pump station and pipeline is currently estimated between $51 and 62 million, which does not include the federally funded treatment plant. After the project is complete, the surface water will be a supplemental source of water, and the Air Force Base will continue to rely on groundwater resources. 

Water is vital and water is not free.

Supporting water in Elmore County is a local, state, and national issue. The Elmore County Commissioners recognize that major action is needed to make the county whole and sustainable for generations to come. The aquifer is not endless, drilling more wells is like sticking more straws into the same cup. 

A 2017 Water Supply Alternatives Report jointly funded by the County Commissioners and the IWRB identified options to begin to address the problem. As part of the implementation of that report, the Canyon Creek Recharge sites were permitted through the Idaho Department of Environmental Quality and have been used successfully, a number of times, to capture runoff events for aquifer recharge.

The report identified diverting water from Anderson Ranch Reservoir as a viable alternative for supplementing water resources in the area. The Elmore County Commissioners successfully obtained a water right permit to divert water from Anderson Ranch Reservoir to Little Camas Reservoir, under certain conditions, for aquifer recharge and irrigation uses in Elmore County - creating the South Fork Boise River Diversion Project. In addition, there is a separate proposal by the State of Idaho and federal government to raise Anderson Ranch Dam to create more reservoir storage space.  While not directly connected to the South Fork Boise River Diversion Project, raising Anderson Ranch Dam could improve the reliability of water available to the Project, which could substantially reduce its size and construction costs.

The Commissioners are actively pursuing the South Fork Boise River Diversion Project to recharge the aquifer in the greater Mountain Home area for the benefit of all. More on Elmore County's proposed South Fork Boise River Diversion Project can be found here.


While the Elmore County Commissioners support the State of Idaho and U.S. Air Force's Mountain Home Air Force Base Sustainable Water Supply Project, the County is not formally involved in that project, and the County's aquifer recharge initiatives are not formally connected to that project. 

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