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Flathead - Stillwater Sediment and Temperature TMDLs

Page history last edited by Christina Staten 11 months, 1 week ago Saved with comment

Flathead TMDL Project Overview & Maps

 Draft Document     Contacts       Project Outreach      Nutrient TMDLs 

Page Contents


Effects of Excess Sediment on Streams & Lakes

Sediment is a naturally occurring component of healthy and stable stream and lake ecosystems. However, excess sediment entering streams may alter channel form and function and affect fish and other aquatic life by increasing turbidity and causing excess sediment to accumulate in critical aquatic habitat areas not naturally characterized by high levels of fine sediment. This may interfere with fish and macroinvertebrate survival and reproduction. For example, it can reduce the availability of suitable spawning habitat for salmonid fishes and can smother eggs and hatchlings. Human activities that can increase the amount of fine sediment entering a stream and alter stream channel form include the removal of riparian vegetation and natural instream barriers, such as large woody debris (tree limbs and logs) and beaver dams. These actions may lead to increased erosion of streambanks and decreases in the number of pools found in the stream.


Effects of High Water Temperatures on Streams & Lakes

Warm stream temperatures have negative effects on aquatic life and fish that depend on cool water for survival. Warmer water temperatures exert more stress on fish by effecting their metabolism and reducing the amount of oxygen available in the water. This may cause coldwater fish and other aquatic species to feed less frequently and use additional energy to survive in thermal conditions above their tolerance range. Human influences that reduce stream shade, increase stream channel width, add heated water, or decrease the ability of the stream to regulate solar heating all increase stream temperatures.



Sediment and Temperature TMDLs Written in 2014 

(contained in the Flathead-Stillwater TMDL document)


Table 1 and Map 1 below show the sediment and temperature TMDLs completed in 2014 that are contained in the "Flathead - Stillwater Planning Area Nutrient, Sediment, and Temperature TMDLs and Water Quality Improvement Plan" that was approved by the U.S. EPA in Denver on December 17, 2014. The document is available on DEQ's TMDL website under "TMDL Documents," and can also be found at the Big Fork, Columbia Falls, Kalispell, Missoula, Polson, and Whitefish public libraries.


Click on the waterbody names in Table 1 to view their water quality summary, see a map of the stream, and to link to their full water quality assessment record. The information is housed in DEQ's Clean Water Act Information Center. You can view records by clicking on "Search," choosing the "By Location" tab, and then selecting "Flathead-Stillwater" in the TMDL Planning Area (TPA) drop-down list. The most current assessment information will be available in the 2016 Water Quality Integrated Report.


Table 1: Sediment & Temperature TMDLs Completed in 2014 

Waterbody & Location Description

(Click Waterbody Name to View Map & Assessment Summary)





Ashley Creek

Ashley Lake to Smith Lake



Ashley Creek

Smith Lake to Kalispell Airport Road



Ashley Creek

Kalispell Airport Road to mouth (Flathead River)



Flathead Lake

See Note 2 


Logan  Creek

Headwaters to Tally Lake



Haskill Creek

Haskill Basin Pond to mouth (Whitefish River)



Sheppard Creek

Headwaters to mouth (Griffin Creek)



Stillwater River

Logan Creek to mouth (Flathead River)



Whitefish Lake

See Note 2


Whitefish River

Whitefish Lake to mouth (Stillwater River)



1. “X” indicates a TMDL was written

2. Flathead and Whitefish Lakes are identified as impaired for sediment on the 2014 list of impaired waters; however, DEQ performed updated sediment water quality assessments for each lake and concluded that neither lake is impaired for sediment. Therefore, sediment TMDLs are not required for either lake.



Map 1: Sediment and Temperature TMDLs completed in the Flathead-Stillwater TMDL Planning Area in 2014 

(Click on map to enlarge

Map of streams in the Flathead-Stillwater TMDL Planning Area with sediment or temperature TMDLs 



Sediment & Temperature Planning Documents



Table 2: Sediment Planning Documents 




Watershed Stratification Approach for Sediment & Habitat Investigation (0.07 MB)

Describes the rationale behind the methodology used by DEQ to characterize and stratify waterbodies to address sediment and habitat condition as it relates to aquatic life and fisheries beneficial uses for use in the TMDL process.


Final Version

Watershed Stratification Procedure for Sediment & Habitat Assessments (0.1 MB)

Details the waterbody stratification procedure used in the development of sediment and habitat sampling and analysis plans (SAPs) and establishes a general framework for achievement of data quality objectives within those SAPs.


Final Version

Sediment & Habitat Longitudinal Field Methods (0.4 MB)

Outlines and describes the methods used by DEQ to collect sediment and habitat related data for streams in the Flathead - Stillwater TMDL project.


Final Version

Sediment and Habitat Assessment Report 

(see Attachment A of the Flathead-Stillwater TMDL document)

Summarizes the methods used and the data collected during the 2008 field effort conducted by DEQ. A map of sampled sites is included in the report.

Draft version previously posted on 3-15-09

Flathead Lake Sediment Beneficial Use Support Assessment (1.43 MB) Water quality assessment report for Flathead Lake supporting the determination that Flathead Lake is not impaired for sediment.



Whitefish Lake Sediment Beneficial Use Support Assessment (1.72 MB) Water quality assessment report for Whitefish lake supporting the determination that Whitefish lake is not impaired for sediment.





Table 3: Temperature Planning Documents 




Flathead-Stillwater Temperature & Flow Monitoring Sampling and Analysis Plan (SAP) (1.03 MB)

Defines sampling objectives, study design, monitoring locations, field methods, and data quality assurance requirements for the 2008 temperature and flow monitoring on Ashley Creek and the Whitefish River.

July, 2008

Final Version

Temperature Assessment Report 

(see Appendix E of the Flathead-Stillwater TMDL document)

Summarizes the data collected in 2008 in accordance with the above SAP. A map of monitoring locations is included in the report. The data was used in a QUAL2K model to assess the influence of shading and streamflow on stream temperatures in Ashley Creek and the Whitefish River. The report discusses the results of this assessment.  

Aug 2009 and Feb 2014 draft versions previously posted




Project Contacts






Christina Staten

Project Coordinator


(406) 444-2836

Dean Yashan

Contact for the sediment and temperature TMDLs


(406) 444-5317

Jason Gildea

Project Manager for Ashley Creek and Spring Creek nutrient TMDLs


(406) 457-5028

Eric Regensburger

Project Modeler

Eric is the DEQ contact for the Flathead Lake watershed model


(406) 444-6714


For a full list of contacts, see the Flathead TMDL Project Contacts page.



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Page Released: October 13, 2011

Last Updated: broken web links repaired October 21, 2016 (page content last updated March 14, 2016)