Impaired Waters and Total Maximum Daily Loads

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Under the federal Clean Water Act, the Total Maximum Daily Load, also known as TMDL, program provides a framework for identifying and cleaning up impaired waters. Section 303(d) requires states to list impaired waters for which the necessary pollution controls have not yet been required and for which a TMDL study has not been written. The state is required to develop a Total Maximum Daily Load for all waters on the 303(d) list. The TMDL is a mathematical calculation of the amount of a specific pollutant a waterbody can absorb and still meet water quality standards. Each TMDL document will include allocations of the acceptable load for all sources of the pollutant. It will also include an implementation plan to identify how the load will be reduced to a level that will protect water quality.  TMDLs go through a 45-day Public Notice period for public review and comment.

TMDLs Under Development

U.S. Environmental Protection Agency Approved TMDLs 


2020 303(d) List TMDL Prioritization

TMDL Prioritization Framework
TMDL Prioritization and Schedule for Missouri 2020 303(d) List of Impaired Waters
TMDL Alternative - Category 5-alt Components


What are TMDLs?   Fact Sheet--PUB2090

TMDL Information Sheets - Brief summaries of information related to waterbodies that are listed as impaired.

TMDL Lawsuit Information - Related to the TMDL Consent Decree established as part of the American Canoe Association, et al. v. EPA, No. 98-1195-CV-W in consolidation with No. 98-4282-CV-W, Feb. 27, 2001.

Missouri 303(d) Information - Includes current and past 303(d) lists, listing methodologies and maps.

Environmental Protection Agency TMDL Pages

Keeping Our Waters Clean - A Video about TMDLs

Keeping Our Waters Clean is an accurate, easy-to-understand video designed to educate and inform the public about TMDL issues. The Missouri Department of Natural Resources was one of the sponsors of the program that aired on MSNBC in 2002.

Keeping Our Waters Clean video grab image

The video is available free of charge to Missouri residents. If you would like a copy to share with others in your community, please call 573-751-1300 or 800-361-4827. Please specify your choice of either the full length version, a condensed 45-minute version (emphasizing nonpoint sources), or a condensed 25-minute version of the video.

The Missouri Department of Natural Resources helped sponsor the national Total Maximum Daily Load video to educate the public about TMDL issues. Watch it online now. Length 44:05 (170KB)

This online video is also available on DVD.  Contact the department at 800-361-4827.