Evaluating the Water Quality Effects of TMDL Implementation: How States Have Done It and the Lessons Learned highlights the diversity of approaches to evaluating the water quality effects of TMDL implementation, explains some of those methods, and conveys lessons learned. It also details terminology challenges and identifies relevant resource materials. The objective of the document is to facilitate communication among water quality programs, especially TMDL programs, and help generate new ideas in this underexplored area.
Evaluating TMDL implementation, especially the ultimate effects on water quality, is challenging but important. It is needed to reveal whether a TMDL and implementation actions are working or should be revised. It also provides information about restoration and protection, ideally making future efforts more effective and efficient, and it helps to demonstrate to the public the impact of TMDL programs and other Clean Water Act programs.
With the ten-year horizon of the 2013 CWA 303(d) Program Vision coming to a close and the next iteration of the Vision dawning, this is an opportune time to continue considering how the effects of TMDL implementation are and can be evaluated, and this document can support such efforts.
Most of the information about state practice included in this document stems from answers to a questionnaire distributed in the fall of 2017 and completed by staff from 39 states and the District of Columbia. Follow-up conversations and independent literature reviews by ELI staff supplement the information from the questionnaire, especially with regard to the section on terminology and the specific examples from practice.
Referenced in the compendium document are two products founded on, but that go well beyond, the questionnaire responses. The Collection of Monitoring Resources contains a list of literary resources providing information about monitoring that can inform evaluation of water quality restoration plan effectiveness. In addition to the title of each resource, the list details the stage(s) of the monitoring process addressed, the level of detail provided, the type(s) of monitoring referenced, whether and where specific topics are addressed, and general notes about what is covered. Examples of Language in TMDLs and Plans that Implement TMDLs Regarding Evaluation of the Effects of Implementation provides examples of how evaluating effectiveness has been covered in TMDLs and TMDL implementation plans, demonstrating the breadth and depth of specifics regarding monitoring and the assessment of monitoring data – how, when, where, and by whom – that have been crafted. Starting with references to particular TMDLs and plans contained in questionnaire responses, ELI staff developed this document by finding the referenced TMDLs and plans, searching through state repositories of TMDLs and TMDL implementation plans for additional examples, excerpting relevant language, and cataloguing the contents.
This compendium and associated products are the result of Cooperative Agreement X7- 83592101-0 between ELI and the U.S. EPA. ELI alone is responsible for errors or inaccuracies. The information provided here is not exhaustive, and is meant only to advance the knowledge of and improve communication among state, tribal, and territorial staff.