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Yaak TMDL Planning Area

Page history last edited by Jordan Tollefson 8 years, 10 months ago Saved with comment

Yaak Nutrients TMDL Project


Project Documents                          Project Outreach



The Yaak nutrients TMDL project includes one stream, the East Fork Yaak River. The East Fork Yaak River is impaired for nitrate+nitrite and a TMDL for the East Fork Yaak River is currently under development. In 2008, sediment TMDLs were completed for three streams in the Yaak River watershed to address sediment impairments on Seventeenmile Creek, Lap Creek, and the South Fork Yaak River. That document can be found here:  Yaak River Watershed Sediment Total Maximum Daily Loads. The purpose of the East Fork Yaak River Nutrient Total Maximum Daily Loads document is to address the nutrient impaired waterbody (East Fork Yaak River) in the Yaak watershed.


The East Fork Yaak River watershed is located in Lincoln County, Montana. Its headwaters are located in the Purcell Mountains west of Lake Koocanusa, and from the headwaters the stream flows westward 14.6 miles to its confluence with the Yaak River (Figure 1). The East Fork Yaak River watershed is composed of two 6th order subwatersheds:  Basin Creek (170101030102), and East Fork Yaak River (170101030103). These fall within the larger Upper Yaak River 5th order watershed (1701010301), and the Yaak 4th order subbasin (17010103). The Yaak subbasin is located within the Kootenai 3rd order basin (170101) and the Kootenai-Pend Oreille-Spokane 2nd order subregion (1701), which is ultimately part of the Pacific Northwest 1st order Region (17). The East Fork Yaak River is the only impaired waterbody within the two 6th order subwatersheds that encompass its watershed on the 303(d) list (Figure 2).



Figure 1. Location of the Yaak TPA                               Figure 2. 303(d) Streams in the Yaak TPA

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



Project Purpose

The state of Montana monitors its waters and conducts water quality assessments to determine if waterbodies are supporting their designated uses. In the Yaak TMDL Planning Area (TPA), all streams in the project area are in the B-1 use classification category.


Streams classified B-1 are suitable for drinking, culinary and food processing purposes after conventional treatment, and must be suitable for bathing, swimming, and recreation; growth and propagation of salmonid fishes and associated aquatic life, waterfowl, and furbearers; and agricultural and industrial water supply. 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 will be published for this project and will include information and results from each of these four steps. The document will also include 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.


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

One waterbody segment in the Yaak TPA is listed in the “Draft 2014 Water Quality Integrated Report” as not supporting or partially supporting one or more designated uses. Table 1 below shows the waterbody segments that will be addressed in this document.


Table 1. Water Quality Impairment Causes for the Yaak TPA Addressed Within this Document 

Waterbody & Location Description

TMDL Prepared

TMDL Pollutant Category

Impaired Use(s)

East Fork Yaak River, headwaters to mouth (Yaak River)

Nitrite + Nitrate


Aquatic Life,

Primary Contact Recreation


Project Status

We anticipate having the TMDL document ready for stakeholder review by April 2014, and available for public comment in May 2014.


Project Contacts






Project Coordinator and Nutrients Project Manager

Jordan Tollefson



(406) 444-5341

Page Released: April 4, 2014

Last Updated:   April 4, 2014


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