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Water: Total Maximum Daily Loads (303d)

Water Quality Improvements

Following TMDL implementation, expectations are high for an impaired water’s condition to begin to change. The ‘Improving’ stage in the impaired waters restoration pipeline is characterized by first allowing time for the implemented pollution control practices to take effect, and second by monitoring to detect improvements. As with tracking implementation, tracking improvements in tens of thousands of waters is an expensive and formidable task that has not been possible for states and EPA alone to carry out on all recovering waters. Where monitoring data are available, changes can be documented and reported. Partial but significant changes may occur but remain short of full water quality standard attainment. For example, incremental improvement may occur when a water body with multiple pollutants is no longer impaired by one or more of its former problems. Also, monitoring aquatic measures of condition may show significant improvement in a specific chemical or physical parameter, or an improved biological community measure.

The TMDL Program Results Analysis Project is not tasked with reporting environmental improvements or full recoveries - those measures are officially tracked through the EPA Strategic Plan. Thus, TMDL results analysis has studied this stage of the pipeline by focusing on approaches for detecting improving conditions and identifying driving factors that are associated with improvements. Several resources of interest related to this final pipeline stage are listed below.

Resources of Interest:

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  • EPA Report: FY2010 Assessment of Improving and Recovered Waters with TMDLs (PDF) (4 pp, 265K), March 2011.
    This national study analyzed the numbers of impaired waters with TMDLs that are fully attaining WQS or have individual causes restored.
  • EPA Report: Evaluating Options for Documenting Incremental Improvement of Impaired Waters Under the TMDL Program (PDF) (91 pp, 1.5MB), November 2008
    This report documents scientifically sound examples of detecting and quantifying incremental improvement and summarizes the key concepts and methods in a consistent framework.
  • EPA Report: Summary of Findings: March 2007 TMDL/Monitoring National Workshop Session on Program Effectiveness Monitoring (PDF) (10 pp, 130K)
    A meeting of national EPA Monitoring and Impaired Waters Listing Programs coordinators compiled these suggestions toward improving effectivenss of their programs with respect to data, collaboration and communication, process efficiencies, analysis, and more.
  • EPA Grantee Report: Implementing Total Maximum Daily Loads: Understanding and Fostering Successful Results (PDF) (154 pp, 1.1MB), December 2008
    This study, completed by Kent State University with funding from EPA grant number 83339301, focuses on the states of Ohio and West Virginia; it addresses the extent to which TMDLs are being implemented, factors that facilitate implementation progress, and steps that can be taken to facilitate further progress on TMDL implementation.
  • Fact Sheet: Implementing Total Maximum Daily Loads -- Understanding and Fostering Successful Results (PDF) (2 pp, 39K), May 2009
    This fact sheet summarizes an EPA grant-funded study of Ohio and West Virginia; it addresses the extent to which TMDLs are being implemented, factors that facilitate implementation progress, and steps that can be taken to facilitate further progress on TMDL implementation.
  • EPA Report: Total Maximum Daily Load (TMDL) Implementation Tracking Needs Assessment: Current Status and Future Needs for States in Regions 5, 6, and 10 (PDF) (37 pp, 1.1MB), March 2008
    This regional study examined several states’ interests in assessing TMDL implementation progress, their capacity for tracking, potential measures of implementation success, and potential assistance roles for EPA for the purpose of partnering in the development of better TMDL implementation data.
  • EPA Grantee Report: TMDL Implementation – Characteristics of Successful Projects Exit EPA Disclaimer
    This Virginia Tech Center for TMDL and Watershed Studies report, funded in part by EPA grant numbers 83217601 and 83156301, provides state TMDL implementation information and reviews ongoing TMDL implementation efforts across the country and their associated TMDLs and implementation plans to identify factors that contribute to successful implementation.
  • 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.
  • Publication: A method for comparative analysis of recovery potential in impaired waters restoration planning (PDF) (20 pp, 348K), August 2009
    This paper appeared in Environmental Management journal in August 2009. It describes an indicator-based method for setting restoration priorities among large numbers of impaired waters through using recovery potential screening.  The paper covers the screening methods, their programmatic purpose, and three state or multi-state scale studies.  The original publication  Exit EPA Disclaimer is available at www.springerlink.com Exit EPA Disclaimer
  • Website: Recovery Potential Screening
    This website is an applied set of tools, techniques and reference information to help states and others compare the restorability of their impaired waters to inform strategies for earlier and greater success in restoration. Many of the recovery potential indicators and restorability screening techniques were developed from insights gained through TMDL program results analysis and apply the lessons learned from the results analysis project. 
  • EPA website: STORET/WQX Database Access
    EPA maintains two data warehouse systems containing water quality information for the nation's waters: the Legacy Data Center (LDC), and the STOrage and RETrieval warehouse (STORET). The LDC is a static, archived database and STORET is an operational system actively being populated with water quality data through the Water Quality Exchange (WQX).
  • EPA Website: Section 319 Nonpoint Source Success Stories
    This website features stories about primarily nonpoint source-impaired waterbodies where restoration efforts have led to documented water quality improvements.
  • Fact Sheet: Summary of EPA's "100 TMDLs Review" (PDF) (2 pp, 827K), December 2009
    This fact sheet summarizes a 2005 national study of the characteristics of a sample of TMDLs from all ten EPA Regions representing numerous pollutants and different settings.
  • Fact Sheet: Impaired waters with TMDLs completed – a GIS dataset (PDF) (2 pp, 333K), December 2009
    This fact sheet describes a publicly available national geopspatial dataset consisting of the thousands of mapped impaired waters that have had at least one TMDL approved or established. 

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