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Bitterroot River Watershed Boundaries & Completed TMDLs
Location of the Bitterroot River Watershed
The Bitterroot River watershed is located in western Montana, bordering the state of Idaho (Map 1 below). The watershed encompasses all of Ravalli County and a portion of Missoula County, including the southwest area of the City of Missoula. The watershed includes the towns of Sula, Conner, Darby, Hamilton, Corvallis, Victor, Stevensville, Florence, and Lolo. The Bitterroot River forms at the confluence of the East and West forks of the Bitterroot River near Conner, MT, and flows north approximately 84 miles until it joins the Clark Fork River near Missoula, MT.
TMDL Planning Areas in the Bitterroot River Watershed & Completed TMDLs
TMDL development occurred in this watershed for a number of years. For TMDL planning purposes, DEQ divided the watershed into three separate TMDL planning areas: Bitterroot Headwaters, Bitterroot, and Upper Lolo (see Table 1 and Map 1 below). Collectively, 56 TMDLs have been completed and published in four separate documents corresponding to these planning areas in 2003, 2005, 2011, and 2014 (see Table 1 below and the Completed TMDLs in the Bitterroot River Watershed page). This project page mainly discusses the TMDLs that were completed for the 2014 Bitterroot Watershed TMDL Project Area document.
[Click on map to enlarge]
Map 1: TMDL Planning Areas in the Bitterroot River Watershed
Table 1: TMDL Planning Areas in the Bitterroot River Watershed and Associated TMDL Documents
TMDL Planning Area &
Planning Area Description
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Completed TMDLs*
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Associated TMDL and TMDL Implementation Evaluation Documents
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Bitterroot Headwaters
Headwater streams of the Bitterroot River to the formation of the Bitterroot River
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8 Sediment
5 Temperature
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2005 "Water Quality Restoration Plan and TMDLs for the Bitterroot Headwaters TMDL Planning Area"
2016 Reimel Creek TMDL Implementation Evaluation
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Bitterroot
The Bitterroot River (from the confluence of the East and West forks of the Bitterroot River to the confluence of the Clark Fork River) and its tributaries. The headwaters of Lolo Creek are not included in this planning area.
|
15 Sediment
6 Temperature
16 Nutrient
2 Metal
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2011 "Bitterroot Temperature & Tributary Sediment Total Maximum Daily Loads and Framework Water Quality Improvement Plan"
2014 "Bitterroot Watershed Total Maximum Daily Loads and Water Quality Improvement Plan"
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Upper Lolo
Headwaters streams of Lolo Creek to the formation of Lolo Creek (the area above Lolo Hot Springs)
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5 Sediment
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2003 "Water Quality Restoration Plan and Total Maximum Daily Loads for the Upper Lolo Creek TMDL Planning Area"
2011 Upper Lolo Sediment TMDL Implementation Evaluation
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To view a single table of all completed TMDLs in the entire watershed, as well as the non-pollutant causes of impairment that are addressed by those TMDLs, see Table A-1 of Appendix A of the 2014 Bitterroot Watershed TMDL document.
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*It is important to understand that a waterbody may be impaired for more than one pollutant (e.g., sediment, lead, aluminum, nitrogen, phosphorus, temperature), and each waterbody-pollutant combination requires a TMDL. Therefore, a waterbody may have more than one TMDL (for example, a waterbody may have both a nitrogen TMDL and phosphorus TMDL). See the Completed TMDLs page.
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"Bitterroot Watershed TMDL Project" History
Water Quality Impairments Investigated During the 2014 Project
The 2014 project included all remaining impairment listings in the watershed that had not been addressed via the previous three TMDL projects (i.e., the 2003 Upper Lolo, 2005 Bitterroot Headwaters, and the 2011 Bitterroot Tributaries). The project is called the “Bitterroot Watershed TMDL Project” because it addressed impairments in all three TMDL planning areas. Table 2 and Map 2 below identify the waterbodies investigated for metals, nutrients, sediment, and/or temperature during this project; Table 2 is not a reflection of the TMDLs that were written, as many previously identified impairments were removed from the impaired waters list as a result of this project (see the Completed TMDLs in the Bitterroot River Watershed page for a table of the TMDLs completed during this project). Additionally, non-pollutant causes of impairment related to sediment and temperature were also addressed for multiple streams in the Upper Lolo TMDL Planning Area via this TMDL document, but are not shown in the table below. Table A-1 of Appendix A of the Bitterroot Watershed TMDL document details both the pollutant and non-pollutant causes of impairment that have been addressed in the Bitterroot River watershed.
Specifics about the water quality assessments and delistings can be found in the below Metals, Nutrients, and Sediment sections. Complete details about each waterbody's probable causes and sources of impairment can be found at DEQ's Clean Water Act Information Center. You may "Search Water Quality Data" by Waterbody Name (the default search method), or by clicking on the "By Location" tab and choosing the "TMDL Planning Area" radio button in the Search by Location options. From the TMDL Planning Area drop-down list, select "Bitterroot," "Bitterroot Headwaters," or "Upper Lolo." Then click "Search." Use Tables 2 , 3, and 4 below to help determine which planning area to choose.
Table 2: Waterbodies Included in the 2014 Bitterroot Watershed TMDL Project
TMDL PLANNING AREA
|
STREAM & LOCATION DESCRIPTION
|
POLLUTANT GROUPS INVESTIGATED*
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METALS
|
NUTRIENTS
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SEDIMENT
|
TEMPERATURE
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Bitterroot Headwaters
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East Fork Bitterroot River
Anaconda-Pintlar Wilderness boundary to mouth (Bitterroot River)
|
X
|
|
|
|
Meadow Creek
Headwaters to mouth (East Fork Bitterroot River)
|
|
|
X |
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Overwhich Creek
Headwaters to mouth (West Fork Bitterroot River)
|
|
|
X
|
|
Bitterroot
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Ambrose Creek
Headwaters to the mouth (Threemile Creek)
|
|
X
|
|
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Bass Creek
Selway-Bitterroot Wilderness boundary to mouth (Bitterroot River)
|
|
X
|
|
|
Bitterroot River
East and West Forks to Skalkaho Creek
|
X |
|
|
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Bitterroot River
Skalkaho Creek to Eightmile Creek
|
|
X
|
X
|
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Bitterroot River
Eightmile Creek to the mouth (Clark Fork River)
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X
|
X |
X
|
|
Lick Creek
Headwaters to mouth (Bitterroot River)
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X
|
X
|
|
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Mill Creek
Selway-Bitterroot Wilderness boundary to mouth (Fred Burr Creek)
|
|
|
|
X
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Miller Creek
Headwaters to the mouth (Bitterroot River)
|
|
X |
|
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Muddy Spring Creek
Headwaters to mouth (Gold Creek) T7N, R19W, S2
|
|
X
|
|
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North Burnt Fork Creek
Confluence with South Burnt Fork Creek to Mouth (Bitterroot River)
|
|
X
|
|
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North Fork Rye Creek
Headwaters to mouth (Rye Creek – Bitterroot River)
|
|
X
|
|
|
Rye Creek
North Fork to mouth (Bitterroot River)
|
|
X
|
|
|
Skalkaho Creek
Headwaters to mouth (Bitterroot River)
|
X |
|
|
|
Sleeping Child Creek
Headwaters to mouth (Bitterroot River)
|
|
X |
|
|
Sweathouse Creek
Headwaters to mouth (Bitterroot River)
|
|
X
|
|
|
Threemile Creek
Headwaters to mouth (Bitterroot River)
|
|
X
|
|
|
Tin Cup Creek
Selway-Bitterroot Wilderness boundary to mouth (Bitterroot River)
|
|
X |
|
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Willow Creek
Headwaters to mouth (Bitterroot River)
|
|
X |
|
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* "X" indicates the pollutant group was investigated for the corresponding stream. Blank cells indicate the pollutant group was not investigated for the corresponding stream.

(Click on map to enlarge)
Map 2: Bitterroot Watershed TMDL Project Area & Included Streams
Metal Water Quality Assessments & Data
Four waterbodies were identified as impaired for metals in the “2012 Water Quality Integrated Report” (Table 3 below). A risk-based approach was applied to the watershed to determine human-caused sources of metals, including the examination of mining history to determine potential source areas. To accomplish this, three rounds of metals sampling took place in 2012 (one high-flow, and two low-flow) on the metals-impaired streams, on additional streams identified as having significant abandoned mining activity, and also on streams without apparent mining activity. A table and map of sampling locations can be found in the 2012 sampling and analysis plan (note that an addendum is included at the end of the document). Samples were analyzed for a suite of total recoverable metals and for low-level mercury. A spreadsheet of the 2012 data (1.36 MB) is available for review (also available in PDF format ~0.4 MB). You may also view Montana's numeric water quality standards (June 2019), for comparison purposes.
The sampled streams were assessed for impairment at the beginning of 2013, following the requirements of DEQ's Metals Assessment Method (found on DEQ's Beneficial Use Assessment webpage). Three of the four previously identified impaired streams were determined not to be impaired (Table 3). Sampling results from 2012 showed a potential for impairment on Lick Creek, however there were not enough samples to perform the assessment method. Three rounds of sampling took place in 2013 (June, July, September) to collect additional data on Lick Creek. The sampling and analysis plan for the June high-flow event contains a table and map of sampling locations. A spreadsheet of the 2013 data is available for review (also available in PDF format).
Appendix C, Metals and Nutrients Data, of the 2014 Bitterroot Watershed TMDL document (PDF, 0.47 MB) provides tables of all the data used in development of the metal TMDLs.
Table 3: Metals Impairments & Updated Assessment Results
TMDL Planning Area
|
Stream/Waterbody
|
Metals Impairments on the 2012 Impaired Waters List1
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Updated Impairment Status / 2014 Impaired Waters List2
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Bitterroot Headwaters
|
East Fork Bitterroot River
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Copper
Lead
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Not Impaired (Delisted)
|
Bitterroot
|
Bitterroot River,
East and West Forks to Skalkaho Creek
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Copper
|
Not Impaired (Delisted)
|
Bitterroot River,
Eightmile Creek to the mouth (Clark Fork River)
|
Copper
Lead
|
Lead
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Lick Creek
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No Impairments
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Aluminum
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Skalkaho Creek
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Mercury
|
Not Impaired (Delisted)
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1. Impairments included in Montana’s “2012 Water Quality Integrated Report”
2. Water quality assessments for metals impairment were performed by DEQ in 2013. The impaired waters list in Montana's 2014 Integrated Report (IR) reflects these assessment results. Where assessment results did not show impairment, those corresponding impairments on the 2012 impaired waters list (303(d) list) were “delisted” and not included on the impaired waters list of the 2014 IR.
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Nutrient Water Quality Assessments & Data
Work on nutrient TMDLs had been ongoing for a number of years prior to the start of the 2014 project, including work on a water quality model specific to this watershed. Thirteen tributaries and two segments of the Bitterroot River were identified as impaired for a nutrient(s) on the “2012 Water Quality Integrated Report” (Table 4). In 2011, DEQ developed a new water quality assessment method for determining nutrient impairment in wadeable streams. All of the tributaries identified as impaired for nutrients were reassessed for impairment using the new method; results are shown in Table 4. Three tributaries were determined not to be impaired for a nutrient, and therefore they did not have a nutrient TMDL developed.
To perform the new assessment method for the tributaries, additional data needed to be collected. Sampling took place for several years prior to the start of the 2014 project, and two rounds of low-flow sampling took place in August and September of 2012. A spreadsheet of the 2012 data (1.36 MB) is available for review (also available in PDF format ~0.4 MB). A table and map of sampling locations can be found in the 2012 sampling and analysis plan. Older data collected by DEQ and other entities such as the USGS and the Tri-State Water Quality Council was also used in the assessments. See "Historical Metals & Nutrient Data" below, for instructions on downloading this data.
Additionally, Appendix C, Metals and Nutrients Data, of the 2014 Bitterroot Watershed TMDL document (PDF, 0.47 MB) provides tables of all the data used in development of the nutrient TMDLs.
Table 4: Nutrient Impairments & Updated Assessment Results
TMDL Planning Area
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Stream/Waterbody
|
Nutrient Impairments on the 2012 Impaired Waters List1
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Updated Impairment Status / 2014 Impaired Waters List2
|
Bitterroot
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Ambrose Creek
|
Total Nitrogen
Total Phosphorus
|
Total Nitrogen
Total Phosphorus
|
Bass Creek
|
Total Nitrogen
Total Kjehldahl Nitrogen
|
Total Nitrogen
Total Phosphorus
|
Bitterroot River,
Skalkaho Creek to Eightmile Creek
|
Total Phosphorus
Nitrite + Nitrate as N
|
Not Impaired (Delisted)
|
Bitterroot River,
Eightmile Creek to the mouth (Clark Fork River)
|
Nitrite + Nitrate as N
|
Not Impaired (Delisted)
|
Lick Creek
|
Total Nitrogen
Total Kjehldahl Nitrogen
Total Phosphorus
|
Total Phosphorus
|
Miller Creek
|
Total Nitrogen
Total Phosphorus
Nitrite + Nitrate as N
|
Not Impaired (Delisted)
*delisted in the 2016 IR
|
Muddy Spring Creek
|
Nitrite + Nitrate as N
|
Nitrite + Nitrate as N
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North Burnt Fork Creek
|
Total Nitrogen
Total Kjehldahl Nitrogen
Total Phosphorus
|
Total Nitrogen
Total Phosphorus
|
North Fork Rye Creek
|
Total Nitrogen
Total Phosphorus
|
Total Nitrogen
Total Phosphorus
|
Rye Creek
|
Total Nitrogen
Total Phosphorus
|
Total Nitrogen
Total Phosphorus
|
Sleeping Child Creek
|
Total Nitrogen
Total Phosphorus
|
Not Impaired (Delisted)
|
Sweathouse Creek
|
Total Phosphorus
|
Total Phosphorus
|
Threemile Creek
|
Total Phosphorus
Nitrite + Nitrate as N
|
Total Nitrogen
Total Phosphorus
Nitrite + Nitrate as N
|
Tin Cup Creek
|
Total Nitrogen
Total Kjehldahl Nitrogen
|
Not Impaired (Delisted)
|
Willow Creek
|
Total Nitrogen
Total Kjehldahl Nitrogen
|
Not Impaired (Delisted)
|
1. Impairments included in Montana’s “2012 Water Quality Integrated Report”
2. Water quality assessments for metals impairment were performed by DEQ in 2013. The impaired waters list in the 2014 Integrated Report (IR) reflects these assessment results. Where assessment results did not show impairment, those corresponding impairments on the 2012 impaired waters list (303(d) list) were “delisted” and not included on the impaired waters list of the 2014 IR.
|
Historical Metals & Nutrient Data
All water quality chemistry data collected by DEQ and EPA are housed in EPA's National Water Quality Portal. Data collected by other organizations such as the Tri State Water Quality Council, whose data collection was funded by DEQ, will also be found in the Water Quality Portal. DEQ's Water Quality Portal Guidance can assist you in downloading data. DEQ suggests downloading data by the Bitterroot watershed HUC (hydrologic unit code): 17010205 (see Section 2.2, Site Parameters, and Section 2.2.4, HUC, of the guidance document).
Sediment Water Quality Assessments
Meadow and Overwhich creeks in the Bitterroot Headwaters TMDL Planning Area, were included on the "2012 Water Quality Integrated Report" as impaired for sediment. DEQ and EPA collected sediment data on the two headwater tributaries in the summer of 2013 to: assess the quality of aquatic habitat conditions, evaluate stream form and function (sediment transport capability), and to estimate the amount of sediment loading from bank erosion. Assessment of the collected data determined that neither Meadow or Overwhich creek are currently impaired for sediment and both streams were removed from Montana's list of impaired waters in 2014. A success story about the Meadow Creek impairment removal/delisting is featured on EPA's website, highlighting restoration work and improved land management practices implemented by the Bitterroot National Forest that led to the water quality improvements.
The middle and lower segments of the Bitterroot River (from Skalkaho Creek to the confluence with the Clark Fork River) were also listed as impaired for sediment on the 2012 list of impaired waters. Data was reassesed and DEQ determined that these two segments of the river are not impaired for sediment, and impairment causes were removed from Montana's impaired waters list in 2014. The 2014 Sediment Beneficial Use Support Assessment for Middle and Lower Segments of the Bitterroot River (PDF, 1.37 MB) provides the rationale delisting sediment as a cause of impairment for the Bitterroot River.
Table 5. Sediment Impairments Removed from the Impaired Waters List
TMDL Planning Area
|
Stream/Waterbody Delisted for Sediment1
|
Bitterroot Headwaters
|
Meadow Creek
Headwaters to mouth (East Fork Bitterroot River)
|
Overwhich Creek
Headwaters to mouth (West Fork Bitterroot Rver)
|
Bitterroot
|
Bitterroot River
Skalkaho Creek to Eightmile Creek
|
Bitterroot River
Eightmile Creek to mouth (Clark Fork River)
|
1. Each waterbody was included on Montana’s 2012 list of impaired waters with a sediment impairment. Updated assessments concluded the streams were no longer impaired for sediment and were removed from the impaired waters list via the 2014 Integrated Report.
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Sediment TMDLs Completed During Other Bitterroot TMDL Projects:
For information on the sediment TMDLs completed in 2011 in the Bitterroot TMDL Planning Area and in 2003 in the Upper Lolo TMDL Planning Area, see the Completed TMDLs in the Bitterroot River Watershed page.
Temperature TMDLs
A temperature TMDL was developed for Mill Creek (see Map 2 above). Temperature TMDLs were also completed for three tributaries and the middle and lower segments of the Bitterroot River in 2011 (see the Completed TMDLs in the Bitterroot River Watershed page).
Temperature data was collected on Mill Creek in the summer of 2013. Data loggers were placed at multiple locations in the stream the week of June 24, 2013. They recorded water temperature every half hour until they were picked up on the second week of September. Stream flow was also measured when the loggers were deployed in June, in August, and when they are retrieved in September. Information on riparian vegetation and shade conditions along the stream was also collected in August. The collected temperature, shade, and flow data was used in a water quality model to determine current thermal loads in Mill Creek and to estimate thermal loading reduction potential (see Attachment A of the Bitterroot Watershed TMDL document (PDF, 3.3 MB) for details on this modeling effort).
Bitterroot River Watershed Contacts
Majority of the project team members for development of the Bitterroot TMDLs are no longer with DEQ. Current program contacts for the Bitterroot are provided in the table below.
DEQ Contact
|
Role
|
Email
|
Phone
|
Hannah Riedl
|
Nonpoint Source Program’s Focus Watershed Coordinator for the Bitterroot
|
Hannah.Riedl@mt.gov
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(406) 444-0549
|
Kristy Fortman
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Bitterroot TMDL Planning Area Sediment TMDL writer, and Acting Supervisor of the Nonpoint Source & TMDL programs
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Kristy.Fortman@mt.gov
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(406) 444-7425
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Page Released: July 17, 2012
Last Updated: July 24, 2019