Department of
Environmental Quality

This region boasts a myriad of water resources: renown hot springs; lakes, reservoirs, and rivers that attract anglers, boaters, and swimmers; and the Lower Portneuf River Valley Aquifer that supplies drinking water to tens of thousands of Idahoans.  Economic activities in this portion of the state include phosphate mining and processing and agricultural production of wheat, potatoes, and sugar beets. These activities have the potential to impact the region's water quality.

Subbasin Assessments and Total Maximum Daily Loads

Listed below are subbasins in which subbasin assessments (SBAs) and/or total maximum daily loads (TMDLs) have been completed for water bodies in DEQ's Twin Falls Region. Click on the subbasin name to link to an overview of water quality in the subbasin, a list of streams and pollutants for which TMDLs were developed, and related documents, including subbasin assessments and TMDLs, addenda, implementation plans, and five-year reviews. (Access the statewide list of SBAs/TMDLs here.)

• Big Wood River Subbasin
• Bruneau River Subbasin
• Camas Creek Subbasin
• Fall Creek Subbasin
• Goose Creek Subbasin
• Little Wood River Subbasin
• Raft River Subbasin
• Salmon Falls Creek Subbasin
• Snake River (Middle) - Upper Snake Rock Subbasin
• Snake River (Middle) Subbasin
• Walcott Lake Subbasin

Ground Water Studies and Reports

• Black Cliffs Ground Water Quality Study: Nitrate Impact (Technical Report 4. October 1994)
• Possible Sources of Nitrate to the Springs of Southern Gooding County, Eastern Snake River Plain, Idaho (Technical Report 38. December 2009)
• Snake Plain Aquifer Technical Report (September 1985)
• Ground Water Vulnerability Assessment, Snake River Plain, Southern Idaho (Technical Report 2. April 1991)
• Nitrate and Emerging Contaminants Evaluation of Springdale, Idaho: Cassia County Nitrate Priority Area (Technical Report 39. December 2009)
• Cumulative Impacts Assessment, Thousand Springs Area of the Eastern Snake River Plain, Idaho (Technical Report 14. July 2000)
• 2005 Update, Thousand Springs Area of the Eastern Snake River Plain, Idaho (Technical Report 27. December 2006)
• Ground Water Report, Oregon Trail Subdivision, Twin Falls, Idaho (Technical Report 33. September 2008)