• If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.

  • Dokkio Sidebar applies AI to make browsing the web faster and more productive. Whenever you open Sidebar, you'll get an AI summary of the web page and can ask any question you like about the content of the page! Try Dokkio Sidebar for free.


Thompson TMDL Project Area

Page history last edited by Jordan Tollefson 9 years, 7 months ago


Project Outreach          Project Documents

Page Contents:

Project Purpose


The state of Montana monitors its waters and conducts water quality assessments to determine if waterbodies are supporting their designated uses. All waterbodies in the Thompson TMDL project area must be maintained suitable for aquatic life, drinking water, agricultural, industrial, and recreational uses. Waters that are determined not to be supporting their designated uses are called impaired and are placed on Montana’s list of impaired waters. Impaired waterbodies and their associated probable causes and sources of impairment are published within Montana’s biennial water quality integrated report.


Montana’s state law, and the federal Clean Water Act that was established by Congress in 1972, require development of total maximum daily loads (TMDLs) for all waterbodies impaired by a pollutant (e.g., metals, nutrients, sediment, temperature). A TMDL is the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards (think of a TMDL as a loading rate). TMDL development includes four main steps:

  • Characterizing the impaired waterbody’s existing water quality conditions and comparing those conditions to Montana’s water quality standards. During this step, measurable target values are set to help evaluate the stream’s condition in relation to the applicable water quality standards.

  • Quantifying the magnitude of the pollutant contribution from each significant source

  • Determining the total allowable load of the pollutant to the waterbody (the TMDL)

  • Allocating the total allowable pollutant load into individual loads for each significant source (referred to as load allocations for nonpoint sources and wasteload allocations for point sources)


The TMDL planning process for this project incorporates a combination of water quality sampling and hydrologic modeling to further identify and quantify metals, nutrient, sediment, and temperature contributions from all significant sources to the streams identified in the table below. For more information about the development of TMDLs, please see the What is a TMDL? page on this site or download our pamphlet: Understanding the TMDL Process.



Project Location & Included Streams


The Thompson TMDL Project Area lies in northwestern Montana and is located primarily in Sanders County, with a small portion in Flathead County (see Map 1 below). The two largest towns in the project area are Thompson Falls and Plains. 

Map 1: Location of the Thompson TMDL Project Area in Montana

  [Click on map to enlarge]

 The Thompson project area is composed of a combination of impaired tributary watersheds. The project area is so named because tributaries to the Thompson River constitute the geographic center of the project area; however, tributaries outside of the Thompson River watershed are also included in the project (see Map 2 below). Table 1 below identifies the streams that are included in this project, as well as their probable causes of impairment as identified in the “2012 Water Quality Integrated Report.” The Thompson River itself is not included because it does not have any identified water quality impairments and does not require TMDLs.


The Thompson project area includes all of, or portions of, three different TMDL planning areas, as identified in Map 3 and Table 1 below: the Thompson, Lower Flathead, and Middle Clark Fork Tributaries TMDL planning areas. The Lower Flathead TMDL Planning Area includes

the lower segment of the Flathead River, but TMDLs for this segment will be addressed by a separate project that will be completed after 2014. However, a major TMDL planning effort is underway in the Flathead Lake watershed involving nutrient, sediment, and temperature TMDLs. See the Flathead TMDLs project page for additional information.  Note that streams within the boundaries of the Flathead Indian Reservation do not fall under state jurisdiction for TMDL development. The Little Bitterroot River and Sullivan Creek both flow into the reservation and therefore only a portion of those streams are included for TMDL development.


Map 2: Thompson Project Area & Included Streams              Map 3: TMDL Planning Areas within the Thompson Project Area

[Click on map to enlarge]                                                          [Click on map to enlarge]



Table 1: Waterbodies and Pollutant Impairment Causes Included in this Project

TMDL Planning Area 

Waterbody & Location Description 

Metals & pH Impairments 1 

Nutrient Impairments 2 

Sediment Impairments 

Temperature Impairments 

Changes to be made for the 2014 Assessment Cycle 





Lower Flathead 

Little Bitterroot River 





Hubbart Reservoir to Flathead Reservation Boundary 

(TN, TP, NO2+3, Chlorophyll-a) 


Sullivan Creek 


Delist for E. coli 


Headwaters to Flathead Indian Reservation 

(Al, Cd, Cu, pH, Zn,) 

(TN, TP) 






Middle Clark Fork Tributaries 

Henry Creek 




Delist for TN and TP 


Headwaters to mouth (Clark Fork River) 


Lynch Creek 




Headwater to mouth (Clark Fork River) 

(TN, TP) 


Swamp Creek 





West Fork Swamp Creek to mouth (Clark Fork River) 

(TN, TP, NO2+3









Lazier Creek 





Headwaters to mouth (Thompson River) 

(TN, TP, NO2+3


Little Thompson River 



List for TN 


Headwaters to mouth (Thompson River) 

(TP, TN) 


McGinnis Creek 




Delist for TP 


Headwaters to mouth (Little Thompson River) 


McGregor Creek 



Delist for TP 


McGregor Lake to mouth (Thompson River) 


1. Specific metals impairments are identified (Al = aluminum, Cd = cadmium, Cu = copper, Zn = zinc) 


2. Specific nutrient impairments are identified (TN = total nitrogen, TP = total phosphorus, NO2+3 = nitrite + nitrate as N) 



Complete details about each waterbody's probable causes and sources of impairment can be found at DEQ's Clean Water Act Information Center. Click on "Search" and then choose the "By Location" tab. Select the TMDL Planning Area (TPA) drop-down list and then select "Thompson". Then click "Search." 




Note that TMDLs are developed for “waterbody-pollutant combinations,” meaning a stream can have more than one TMDL. For example, a stream may be impaired for both nitrogen and phosphorus, and therefore will have both a nitrogen TMDL and a phosphorus TMDL.



Project Plans


This project includes development of metals, nutrients, sediment, and temperature TMDLs for the streams identified in Table 1 above. Details for each can be found below. Note that Sullivan Creek was identified as impaired for e. coli, a pathogen, on the 2012 Integrated Report. However, recent DEQ sampling results do not support a pathogen impairment, and a pathogen TMDL will not be written for Sullivan Creek.



Sullivan Creek in the Lower Flathead TMDL Planning Area is identified as impaired for aluminum, cadmium, zinc, and pH. DEQ and EPA conducted metals water quality sampling on Sullivan Creek in 2011 and 2012. Samples were analyzed for a full suite of metals. Water quality assessments are being performed with the new data, using DEQ’s Metals Assessment Method. A TMDL will be written for all determined metals impairments.


The sampling and analysis plans for the 2011 and 2012 sampling, detailing sample locations and the parameters collected, can be found on the Thompson Project Documents page.



Every stream included in this project is identified as impaired for a nutrient(s) on the 2012 Integrated Report (see Table 1 above). DEQ and EPA conducted nutrient sampling for each stream in 2011 and 2012 to collect additional samples in order to perform water quality assessments to determine or verify nutrient impairment. A table and map of sampling locations can be found in the sampling and analysis plans on the Thompson Project Documents page.


DEQ’s water quality assessment method for determining nutrient impairment in wadeable streams requires a minimum number of samples to provide more certainty in the impairment determinations. TMDLs will be written for all determined nutrient impairments. TMDLs will also be written for any stream currently identified as impaired for a nutrient(s), but does not have the minimum number of samples required to implement the assessment method.



Sediment data was collected by DEQ in 2011. In-stream fine sediment data and streambank erosion data was collected, and a survey of unpaved roads in the project area was conducted. Assessment reports of current sediment conditions in the streams, and sediment delivery from streambank erosion and unpaved roads are being drafted. An assessment of sediment contribution from upland sources is also being conducted using a water quality model (examples of upland sources include grazing lands and timber harvest areas, among others). Reports will be posted on the Thompson Project Documents page for stakeholder review and comment.



Temperature data has been collected on Lynch and McGregor creeks. Temperature data loggers were placed at multiple locations in both streams to record stream temperature every half hour 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 is being used in a water quality model to estimate thermal loads in both streams. A temperature assessment report will be posted on the Thompson Project Documents page, once completed.



Project Schedule


All TMDLs are scheduled to be complete before the end of 2014. For project status updates and information on stakeholder and public meetings, see the Thompson Project Outreach page.



Project Contacts


This project is a joint effort between the Montana Department of Environmental Quality (DEQ) and the U.S. Environmental Protection Agency (EPA).







Project Coordinator Jordan Tollefson DEQ jtollefson@mt.gov (406) 444-5341

Project Manager:  Nutrients


Lisa Kusnierz



(406) 457-5001

Project Manager:  Metals

Lou Volpe



(406) 444-3548

Project Manager:  Temperature Jordan Tollefson DEQ  jtollefson@mt.gov  (406) 444-5341 


Page Released: March 8, 2013

Last Updated:   October 25, 2013


      Click on the Adobe icon if you need to download the free Adobe Acrobat software in order to view the documents on this page.