Lower Beaverhead and Upper Jefferson Temperature Total Maximum Daily Loads (TMDLs)

Map Showing Lower Segment of Beaverhead River & Upper Segment of Jefferson River

(Click on image to enlarge) 

TMDL Document

The "Lower Beaverhead River and Upper Jefferson River Temperature TMDLs" document was approved by the U.S. EPA in November of 2014 and is available on DEQ's Final TMDL Documents webpage (click on the "Upper Missouri" basin tab). Copies of the final document are also available at the Twin Bridges and Whitehall public libraries. The document contains a temperature TMDL for the lower segment of the Beaverhead River (from Grasshopper Creek to the confluence with the Jefferson River) and a temperature TMDL for the upper segment of the Jefferson River (its headwaters to the confluence with the Jefferson Slough). 

A public meeting to discuss this document was held on July 17, 2014 in Whitehall. The public meeting presentation (2.09 MB) and public notice are still available for download. 

Project Location

The Beaverhead watershed is located in Beaverhead County, with a small portion in Madison County and includes the towns of Dillon and Twin Bridges. The Beaverhead watershed encompasses fourth-code hydrologic unit code 10020002, which begins at the outlet of the Clark Canyon Reservoir and flows northeast 79.5 miles before joining the Big Hole River to form the Jefferson River. The watershed is bounded by the Pioneer Mountains on the west, the Ruby Range to the east, and the Snowcrest Range and Blacktail Mountains to the south. The impaired temperature segment of the Beaverhead River begins at Grasshopper Creek and ends at the confluence of the Jefferson River. 

The Upper Jefferson watershed encompasses approximately 734 square miles in Jefferson, Madison, and Silver Bow counties, beginning at the Jefferson River’s point of origin near Twin Bridges and extending to its confluence with the Jefferson Slough near Whitehall and Cardwell. The watershed area includes a dozen or more tributary streams that drain portions of the Tobacco Root Mountains to the south and the Highland Mountains to the north. 

Project History & Temperature Data

The Montana Department of Environmental Quality identified the lower segment of the Beaverhead River and the upper segment of the Jefferson River as being impaired (not meeting water quality standards) for temperature (Table 1). The TMDL planning process for this project incorporated a combination of water quality sampling and hydrologic modeling to further identify and quantify temperature contributions from all significant sources. Information from the 2009 Big Hole and 2006 Ruby TMDL projects was included in the analysis of the Jefferson River. The "Middle and Lower Big Hole Planning Area" and "Ruby River Watershed" TMDL documents can be found on our Final TMDL Documents webpage (click on the "Upper Missouri" basin tab).

Temperature data was collected on the Beaverhead River in 2005 and 2009 and the Jefferson River in 2009. Temperature data loggers were placed at multiple locations in both rivers to record stream temperature at hourly increments during the warmest months of the year. Stream flow and riparian shade data was also collected, including vegetation type and density, and the amount of shade covering the stream channel. This information was used in a water quality model to estimate thermal loads in both rivers. The Beaverhead River Temperature Modeling report can be found in Appendix B of the final TMDL document, and the Jefferson River Temperature Modeling Report in Appendix C. 

Project Contacts

1. Kristy Fortman was the previous DEQ Beaverhead River Project Coordinator and Project Manager for the temperature TMDLs; Kristy has left DEQ.