Decade-Long Journey to Success: Bridging Implementation with TMDL Development for Muddy Creek Watershed in Virginia

TMDL programs are critical in attaining water quality goals and restoring impaired waters by calculating pollutant loads in a manner consistent with water quality standards. However, the lack of comprehensive information on the outcomes of the TMDL program prevents EPA from determining if TMDL implementation activities are occurring in a timely manner and the extent to which TMDLs are restoring impaired waters. Therfore, there is a great need to report valuable information on TMDL implementation activities and associated water quality improvements after TMDL development. Although there is no federal requirement that implementation plans be part of mandatory components for TMDL approval, EPA's draft TMDL guidance in 1999 specified the implementation plan as one of ten elements for TMDL submittal. Many states now require such plans or the inclusion of some implementation information in the TMDL.This paper provides a summary of the decade-long journey in the Muddy Creek watershed in Virginia from TMDL development in 1998 to successfully achieving ambient water quality improvement through effective TMDL implementation for multiple pollutants (nutrient, pathogen and benthic). It further presents example results from parallel TMDL research studies that address key technical issues in the TMDL process (e.g. uncertainty analysis and critical condition). The TMDL implementation in the Muddy Creek watershed demonstrates many benefits of adaptive management and follow-up monitoring, which allows water quality improvements to be recorded through monitoring as they are being achieved and also helps to ensure the most cost-effective practices are implemented. It also provides a measure of quality assurance, given the uncertainties which exist in any water quality models used during TMDL development and a good mechanism for developing public support.