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Big Lost River Basin

Big Lost River Basin Hydrologic Investigation

The Big Lost River Basin is located in south-central Idaho within Butte and Custer Counties. The basin serves as an important tributary to the Eastern Snake Plain Aquifer. 

From 2018-2022, IDWR conducted a project to characterize the surface and groundwater hydrology of the Big Lost River Basin. The U.S. Department of Energy (DOE) provided funding for the project through a Supplemental Environmental Project (SEP) grant. DOE participation in this project was undertaken in connection with the settlement of an enforcement action taken by the Idaho Department of Environmental Quality for alleged violations of the requirements of the Hazardous Waste Management Act. 

IDWR partnered with the Idaho Geological Survey (IGS) and the United States Geological Survey (USGS) to complete the following objectives: 

  • Installed stream gages and performed multi-year seepage studies to examine surface water-ground water interactions between the Big Lost River and the aquifer system
  • Developed a hydrogeologic framework and groundwater budgets for the basin  
  • Installed new monitoring wells to expand water level data collection efforts 
  • Conducted a water quality study
Piezometer nest in the Big Lost
Piezometer nest installed in the Big Lost River Basin

Project Reports

June 2022BLRID & WD34Supporting data for “Groundwater Budgets for the Big Lost River Basin, South-Central Idaho, 2000-2019” (IGS, in review)
Ditch rider logs from Water District 34, 2015-2018
Storage balance spreadsheets from the Big Lost River Irrigation District, 2015-2019
February 2022IDWRUpdate of Ground Water Conditions in the Big Lost River Valley
September 2021USGSSurface-Water and Groundwater Interactions in the Big Lost River, South-Central Idaho
September 2021USGSHydrogeologic Framework of the Big Lost River Basin, South-Central Idaho
August 2019IDWRBig Lost River Basin Well Installation Report
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