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Water: Total Maximum Daily Loads (303d)

TMDL Implementation and Tracking

The development of large numbers of TMDLs is relatively recent -- most TMDLs are just a few years old. Although large numbers of TMDLs exist, there has been uncertainty about how many have been implemented. Implementing a TMDL for an impaired water body involves applying the pollution control practices necessary to reduce the pollutant loads to the extent determined necessary in the TMDL. These practices usually consist of point source control permits and/or non-point source control Best Management Practices (BMPs).

Because there are often numerous control practices involved in a single TMDL's implementation, it would be particularly complex and expensive for states or EPA to track all implementation actions under all TMDLs. Moreover, whereas EPA oversees and approves TMDL development by states, the Agency does not have authority over their implementation. Nevertheless, states and EPA alike recognize TMDL implementation as a crucial stage en route to impaired waters restoration. Thus, the Implementation stage is among the most heavily studied of the five stages. The TMDL Program Results Analysis Project has analyzed existing implementation data and tracking capacity, funded studies of implementation rates and their driving factors, and developed resources of interest about TMDL Implementation (below).

Resources of Interest:

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

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