As we move to develop and implement TMDLs that will materially affect point and nonpoint source control requirements, it is incumbent on all stakeholders to ensure that TMDLs will be directed to appropriate and attainable designated uses and associated water quality standards. TMDLs
require significant investments of public resources by EPA and its State Agency partners to develop and implement and even greater resources by regulated entities to participate in the TMDL process and implement the required controls. Moreover, there are significant costs and implications
to society as a whole due to the determination of TMDL priorities as well as land use planning implications from TMDLs. As recommended recently by the National Academy of Sciences, states and EPA should follow a “ready, aim, fire” approach to determining where TMDLs are necessary.
Unfortunately, due to agency resource limitations and political and technical challenges, few designated use reviews have been conducted ahead of TMDL development. Thus, we have been left with a “ready, fire, aim” approach that often forces stakeholders to try to salvage a reasonable
result by tweaking the margins (such as through modeling issues and implementation strategies). Over the past several years, we are beginning to see states move to address the fact that most of the designated uses on the books today were political/aspirational default designations.
There is an increasing realization that Clean Water Act requirements have evolved to the point that we must better define applicable designated uses to avoid the misdirection of public and societal resources. This is particularly vital with regard to urban wet weather discharges such as
storm water and combined sewer overflows. It is also critical for dissolved oxygen reasons in poorly flushed streams and areas that experience very high summer/fall ambient temperatures. In these circumstances – wet weather and poorly flushed/warm systems – the generic
designated uses and associated water quality standards frequently cannot be met due to natural causes. This presentation will explain the process for meaningfully evaluating and, as appropriate, refining designated uses in advance of TMDL development. We will also provide several examples
of refined uses that are being proposed/implemented. We will present recent and ongoing efforts including the ongoing work on the Chesapeake Bay Use Attainability Analysis, an initiative beginning on the Ohio River, as well as several other local case studies.
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