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EPA Rebuffed on Attempt to Use Stormwater Flow as a Surrogate for Sediment Content in a TMDL


By Larry Kane, Attorney, Bingham Greenebaum Doll LLP

In an issue of first impression, the U.S. District Court for the Eastern District of Virginia has rejected EPA’s proposed use of stormwater flow as a surrogate for sediment load in a total maximum daily load (TMDL) allocation for an impaired waterway.  The court found as a matter of law that the “flow” of stormwater is not a pollutant under the Clean Water Act and, thus, could not be the basis of a TMDL.  The decision is Virginia Department of Transportation v. United States Environmental Protection Agency, _____ F.Supp.2d ____, 2013 U.S. Dist. LEXIS 981 (January 3, 2013).

The controversy centers on an impaired waterway, Accotink Creek, a 25-mile long tributary of the Potomac River.  After the Virginia water quality agency failed to prepare a TMDL to address benthic impairment in the waterway, EPA undertook development of a TMDL.  Under Section 303(d)(1)(C) of the Clean Water Act, the State having jurisdiction over an impaired waterway is to prepare a TMDL setting the maximum daily loads of those pollutants identified as causing or contributing to the impairment that may be discharged by each source as determined to be allowable to meet the applicable water quality standards, taking into account seasonal variations and providing a margin of safety.

Apparently, stormwater sediment is believed to be a significant factor in the benthic impairment identified in Accotink Creek.  The court observed that EPA crafted the TMDL to limit the flow rate of stormwater into the creek to a certain volume per acre-day.  EPA indicated that the purpose of the proposed limit on stormwater flow was to create an indirect limit on the amount of sediment that could be allowed to discharge into the creek.  EPA thus referred to stormwater flow as a surrogate for sediment load.  Interestingly, the parties stipulated that sediment is a pollutant but stormwater is not.

The court framed the issue as whether the Clean Water Act authorizes EPA to regulate the amount of a pollutant in the impaired waterway by setting a TMDL for the flow of a nonpollutant into the waterway.  To decide the statutory interpretation issue, the court employed a Chevron analysis.  Ultimately, the court concluded via a straightforward analysis that, since Section 303(d)(1)(C) requires a TMDL for pollutants and since stormwater is not a pollutant, the TMDL cannot set limits for stormwater flow.  EPA’s argument that a nonpollutant, stormwater flow, could be legally limited as an effective substitute or surrogate for the real pollutant, sediment, was dismissed by the court as unsupported by the Clean Water Act.  In essence, the court opined that, whatever use surrogates may appropriately have under the statute, a substance must be a pollutant in its own right before it can be limited as a surrogate for another pollutant.  The court repeatedly expressed puzzlement that sediment, indisputably a pollutant, was not used as the basis for the TMDL intended to limit sediment loading to the creek.

The decision gives rise to speculation concerning its potential ramifications for EPA’s stormwater permitting rules.  Since a TMDL is a blueprint for NPDES permit limits for the various point sources addressed by the TMDL, it is difficult to see how stormwater “flow” can be a limited parameter in an NPDES permit if it is not a pollutant that can be limited in a TMDL.  Interestingly, it may be observed that the definition of storm water discharge associated with small construction activity provided in EPA’s seminal stormwater permitting rule, 40 CFR 122.26(b)(15), includes a statement that “the pollutant(s) of concern” in such stormwater “include sediment or a parameter that addresses sediment (such as total suspended solids, turbidity or siltation) and any other pollutant that has been identified as a cause of impairment . . . .”  [Emphasis added.]  Notably, stormwater “flow” is conspicuously absent in this description.

To view a complete PDF of the January/February 2013 issue of the Environmental Letter, click HERE.


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