Water: Total Maximum Daily Loads (303d)
Overview of TMDL Program Results Analysis
For much of the TMDL Program's history, it has been difficult to analyze the program's environmental results because the entire sequence of TMDL development, TMDL implementation and impaired waters recovery often takes several years. As of January 2011, over 45,000 TMDLs have been developed. More TMDLs are now maturing and producing results that provide an opportunity to assess how well the TMDL Program is working. Results analysis involves assessing measures of environmental outcomes, their probable causes, and program progress in order to generate the insights needed to improve impaired waters programs. The TMDL Program Results Analysis Project was undertaken to improve our understanding of TMDL-specific program results patterns, explain these patterns, and develop appropriate technical, programmatic, and policy actions to incorporate these findings at state, regional, and national program levels. These TMDL-specific results analyses supplement the national tracking of broader water program measures carried out under the EPA Strategic Plan.
The Clean Water Act's impaired waters program pipeline (above) is a simplified graphical representation of how impaired waters are restored. The pipeline's programmatic stages include:
- listing (identifying impaired or 303(d) waters and the causes of their impairments),
- planning (development of the TMDL, TMDL alternative, and/or Implementation Plan),
- implementing (applying controls, i.e., point source permits or nonpoint source Best Management Practices (BMPs)),
- improving (making incremental progress in environmental condition but still short of water quality standards), and
- recovery (fully meeting water quality standards).
Although the primary role of EPA’s TMDL Program is limited by statute to the first two stages of the pipeline, delegated state, tribal and territorial TMDL programs carry on the latter three stages with EPA assistance. TMDL Program results analysis has intentionally focused on program results at all five stages to learn about progress and the effects of EPA’s programs at each stage. This Web site’s structure is based on the pipeline concept, with a subpage of results analysis products and resources for each stage. Broader, overview products that address most or all of the stages are listed below.
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
- Fact Sheet: The TMDL Program Results Analysis Project (PDF) (2 pp, 105K), May 2009
This fact sheet summarizes the aims, methods and outputs of this program evaluation project undertaken by EPA in order to generate the insights needed to make TMDL Program improvements.
- Publication: The TMDL Program Results Analysis Project: Matching Results Measures with Program Expectations (PDF) (17 pp, 107K), June 2007
This paper provides a detailed description of the aims, methods and outputs of this program evaluation project undertaken by EPA in order to generate the insights needed to make TMDL Program improvements. Published in the Water Environment Federation’s TMDL2007 conference proceedings.
- Fact Sheet: The Clean Water Act "Impaired Waters Restoration Pipeline" (PDF) (2 pp, 48K), May 2009
This fact sheet describes how impaired waters pass through five main stages as they are listed, acted upon, and restored under the Clean Water Act.
- Fact Sheet: Total Maximum Daily Loads (PDF) (2 pp, 110K), May 2009
This fact sheet summarizes national progress on developing and finalizing tens of thousands of TMDLs during the past two decades.
- EPA Report: TMDL Program Results Analysis Measures and Methods Report (PDF) (161 pp, 2.6MB), August 2006.
This report presents potential TMDL results tracking measurements obtainable with existing data.
- Publication: TMDL Implementation: Lessons Learned (PDF) (15 pp, 282K), June 2007
Virginia Tech Center for TMDL and Watershed Studies, funded in part by EPA grant 83156301, provided state TMDL implementation information and reviewed ongoing TMDL implementation efforts across the country to identify factors that contribute to successful implementation. Published in the Water Environment Federation’s TMDL2007 conference proceedings.
- Fact Sheet: 2002 Impaired Waters Baseline National Geospatial Dataset (PDF) (2 pp, 133K), December 2009
This fact sheet describes a publicly available GIS dataset of the impaired waters national baseline of 2002, a major tracking and national performance reporting reference date for EPA.
- Fact Sheet: 303(d) Listed Impaired Waters State, Watershed and National Geospatial Datasets (PDF) (2 pp, 474K), January 2010
This fact sheet describes the most recent publicly available GIS data on 303(d) listed impaired waters, available at watershed, state or national scale. Dates vary by state.
- Fact Sheet: Watershed Boundaries for the 2002 Impaired Waters Baseline National Geospatial Dataset (PDF) (2 pp, 245K), December 2009
This fact sheet describes a publicly available GIS dataset consisting of the watershed boundary delineations for the impaired waters national baseline of impaired waters through reporting year 2002, a major tracking and national performance reporting reference date for EPA.
- Fact Sheet: The Impaired Waters with TMDLs National Geospatial Dataset (PDF) (2 pp, 333K), December 2009
This fact sheet describes a publicly available, national geospatial dataset consisting of the thousands of mapped impaired waters that have had at least one TMDL approved or established.