Monday, January 7, 2013

Court Rejects Storm Water Flow TMDL for Accotink Creek in Virginia


The federal district court for the Eastern District of Virginia ruled last week in Virginia Department of Transportation v. US EPA that EPA could not set a total maximum daily load (TMDL) for storm water flow.  The TMDL had been developed using a flow limitation in Accotink Creek as a proxy for sediment, which it believed (perhaps correctly) was causing excessive sedimentation in the creek, resulting in  harmful impacts on benthic life.  The court ruled that EPA could not use flow in the stream, which is not a pollutant under the Clean Water Act, to regulate a pollutant such as sediment.

Some news outlets have reported that the court forbade EPA from limiting one pollutant as a surrogate for another. That is incorrect.  The court did not prohibit the use of one pollutant as a surrogate for another (e.g., TSS as a surrogate for sedimentation).  Rather, it rejected the limitation of one measurable parameter that is not a pollutant ( stream flow) as a substitute for a pollutant (sediment). 

Some  WVNPDES permits contain surrogate limits, and these are not per se prohibited under the  court’s decision.  

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