Bonita Superior TMDL Project

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Project Purpose

The state of Montana monitors its waters and conducts water quality assessments to determine if waterbodies are supporting their designated uses. Waterbodies in the state of Montana have been classified to designate what beneficial uses they must support. The waterbodies in the Bonita – Superior TMDL project area must be maintained suitable to support the uses of: agricultural, industrial, recreational, and drinking water uses, as well as support of fish and aquatic life. Waters that are determined not to be supporting their designated uses are considered 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:


  • Assessing 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 amount of the pollutant contribution from each significant source
  • Determining the total allowable load of the pollutant to the waterbody (i.e., 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)


A TMDL document has been published for this project and includes information and results from each of these four steps. The document also includes recommended land management activities for improving water quality in this project area, and a monitoring strategy to evaluate progress toward attainment of water quality standards. The "Bonita-Superior Metals TMDLs" document can be found on DEQ's Final TMDL Documents webpage.


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 (580 kb).


Project Overview

The project area (Figure 1) encompasses approximately 50 square miles in western Montana, near the town of Superior and former town site of Bonita. The project area includes three watersheds draining to the Clark Fork River. Flat Creek and Hall Gulch are within the Middle Clark Fork Tributaries TMDL Planning Area, and both Wallace and Cramer are located in the Clark Fork Drummond TMDL Planning Area. These boundaries were defined in 2000, but are altered for this project in the interests of efficiency (Figure 2). The Bonita – Superior Metals TMDL project includes all the Clark Fork River tributaries from both of these TMDL planning areas where metals impairments have been identified. These metals impairments have been re-assessed by DEQ’s Monitoring and Assessment program, and TMDL development reflects those reassessments. A number of metals impairments reported in the 2012 Integrated Report will be removed from the 2014 Integrated Report due to non-impairment, and several new metals impairments will be added. These are discussed below in the context of the individual streams.


Location of the Bonita-Superior project area

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Figure 1: Location of the Bonita-Superior TMDL Project Area




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Figure 2: TMDL Planning Area Boundaries Related to the Bonita-Superior Project


Figure 2 shows the Middle Clark Fork Tributaries and Clark Fork – Drummond Tributaries TMDL Planning areas (in light green), and the Bonita – Superior Project Area (in orange). Because the metals-impaired streams are a small subset of the streams in these planning areas, the metals TMDLs were separated into a smaller, discrete project.


Wallace Creek

Wallace Creek is located just east of Clinton, MT. The Wallace Creek drainage includes the Cape Nome and Hidden Treasure mines. A mill was constructed along Wallace Creek to process copper ore bound for smelters in Anaconda. Operations were generally small-scale and short-lived. The site is listed as a priority abandoned mine by DEQ's Remediation Division, but no remedial actions have been performed. The former mill site is currently a gravel pit. Wallace Creek is listed for copper and zinc impairments in the 2012 Water Quality Integrated Report, but following re-assessment, the zinc impairment will be removed for the 2014 Integrated Report.


Cramer Creek

Cramer Creek drains into the Clark Fork River between Clinton and Drummond. Two open-pit mines operated during the late 1940s and 1950s: the Blacktail (silver-lead) and Arrowhead (manganese) mines. Ore was milled on the Blacktail (aka Linton) property, adjacent to Cramer Creek. This site is listed as a priority abandoned mine by DEQ's Remediation Division, and was referred to the U.S. Bureau of Land Management (BLM), which administers the land. The BLM reclaimed the property between from 2001 to 2004. On the 2012 Integrated Report, Cramer Creek has impairments due to arsenic, barium, cobalt, copper, lead and mercury. After re-assessment of the water quality in Cramer Creek, arsenic, barium, cobalt, copper and mercury will be removed from the 2014 Integrated Report. However, the stream was determined to be impaired for aluminum, and this impairment will be added.


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Flat Creek & Hall Gulch

Flat Creek drains into the Clark Fork River at Superior. The Flat Creek watershed includes the Iron Mountain Mine Mill site, which is an abandoned mine/mill site currently listed on EPA’s National Priority List (NPL), also know as “Superfund”. Metals sources in the project area are well known and have been investigated through numerous efforts by the state and EPA. It is unlikely that TMDL development activities will provide any new information regarding sources in this area. The Flat Creek watershed downstream of the mine site is an operable unit (OU) of the NPL site. Other OUs include the town of Superior and the Wood Gulch waste rock repository. Flat Creek’s metals impairments as reported in the 2012 Integrated Report include antimony, arsenic, cadmium, copper, lead and mercury. Based on recent re-assessment, the copper impairment will be removed and a zinc impairment will be added for the 2014 reporting cycle.


Hall Gulch is a tributary of Flat Creek, and its watershed includes the Belle of the Hills mine and the Dillon Millsite. The former mining town of Pardee was located in Hall Gulch. Hall Gulch was not on the 2012 or previous Integrated Reports, but it will be listed for 2014 with impairments related to antimony, arsenic, lead, iron, and zinc.


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The following metals TMDLs were prepared for streams in the project area:



Metal TMDL(s)

Cramer Creek

Aluminum, Lead

Wallace Creek


Flat Creek

Antimony, Arsenic, Cadmium, Lead, Zinc, Mercury

Hall Gulch

Antimony, Arsenic, Lead, Iron, Zinc




Bonita-Superior TMDL Document & Project Status

The "Bonita-Superior Metals TMDLs" document was approved by the U.S. EPA on May 9, 2013. The final document can be found on DEQ's Final TMDL Documents website. A copy of the document can also be found at the Missoula and Superior public libraries. Several comments were received on the draft document during the public comment period, and responses to comments are contained in Section 8.2 of the document.


Two public meetings were held on March 18: one at the Missoula Public Library and the second at the Commissioner's meeting room in the town of Superior (300 River St.). The presentation (4.88 MB) from the meeting is available for review. The same information was presented at each meeting. The the public notice for the meeting is also available.


* The stakeholder draft version of the document has been removed from the table below 


Date Posted

Review Deadline

Bonita-Superior TMDL Project Plan (0.4 MB)



Not Applicable

Bonita Superior Draft Metals TMDLs - Stakeholder Review Version


Appendix A: Watershed Description Maps

Appendix B: Metals Surface Water Data

Appendix C: Cleanup Funding Options





The final document has been approved by EPA. See above for details.



Project Contacts


This project was completed in May 2013.

Eric Sivers was the project manager, and he can be reached at or (406) 444-0471.


Page Released: December 10, 2012 

Last Updated: September 16, 2013