EPA Working on Guidance to Help States Develop, Revise TMDLs for Water Bodies

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By Amena H. Saiyid  

The Environmental Protection Agency is developing guidance on implementing the total maximum daily load requirements of the Clean Water Act, including recommendations for states that want to modify existing TMDLs, according to documents circulated at a meeting April 23.

The other guidance document circulated at the National Association of Clean Water Agencies' National Environmental Policy Forum addresses development of multi-jurisdictional TMDLs for water bodies that may cross state boundaries.

James Pletl, vice chairman of NACWA's Water Quality Committee, said April 23 that EPA is seeking informal review of the two documents, both of which are in draft form, and is accepting comments until May 2.

A TMDL is the calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards and how the load is allocated among the various sources of that pollutant.

Pletl, who also is the water quality director for the Hampton Roads Sanitation District in southern Virginia, said the document on revising and withdrawing TMDLs would allow states to revise their TMDLs without having to obtain EPA approval.

Modifications to TMDLs Addressed.

In the draft guidance, EPA said current regulations and guidance governing the establishment of TMDLs do not specifically address the appropriate circumstances or procedures for revising or withdrawing TMDLs established or approved by EPA.

“However, the need to revise or withdraw TMDLs is increasing as States make progress in implementing over 46,000 existing TMDLs. Additionally, adoption of numeric nutrient criteria and new pathogen criteria may impact existing TMDLs,” EPA said.

For instance, in the draft EPA would offer states the option to make changes to TMDL load allocations as long as the changes would not increase the total amount of pollutants entering the waters. In that situation, EPA recommends in the draft that the TMDL documents submitted by states explicitly identify circumstances under which adjustments are anticipated and the criteria and process that the states intend to apply.

EPA emphasizes the use of water quality trading as a tool for meeting TMDLs and notes that states must indicate clearly that wastewater treatment plants can use water quality trading as a way to meet their water quality-based effluent limits for pollutants such as nitrogen or phosphorus. However, EPA said that states cannot allow changes in waste load allocations between point sources and nonpoint sources after the TMDL has been approved.

Fredric Andes, a partner with Chicago-based Barnes & Thornburg, said the latest iteration of this document represents a “significant change” from the previous draft document that was floated in 2007.

Andes, who was present during the discussion, said the earlier version allowed states to reallocate waste loads between point sources and nonpoint sources. “Point sources and nonpoint sources cannot interchange waste allocations under this document,” Andes said.

Multijurisdictional Guidance Called Flexible.

In contrast to the guidance for revising and withdrawing TMDLs, Andes said, the document on multi-jurisdictional TMDLs is more flexible.

For instance, he said, the TMDLs for the Chesapeake Bay and the Snake River in Idaho are examples of different approaches that would be acceptable under the new draft guidance.

The Chesapeake Bay TMDL, which EPA developed in December 2010 as a result of a settlement reached with the Chesapeake Bay Foundation, had allocations for every source and every watershed in the region. In contrast, Andes said, the allocations in the TMDL developed for the Snake River were left up to the jurisdictions. The Snake River-Hell's Canyon TMDL addresses phosphorus pollution in Idaho and Oregon and was developed in July 2003 and revised in September 2004.

Andes said the multi-jurisdictional guidance is “a good thing because it is not prescriptive. ”

By Amena H. Saiyid  


Considerations for Revising and Withdrawing TMDLs is available at http://www.nacwa.org/images/stories/public/2012-04-16tmdlrev.pdf.

Considerations for the Development of Multijurisdictional TMDLs is available at http://www.nacwa.org/images/stories/public/2012-04-16tmdljur.pdf.