The U.S. Supreme Court has unanimously endorsed a common-sense, restricted definition of “discharge of pollutants” under the federal Clean Water Act (CWA). In its Jan. 8 ruling in Los Angeles County Flood Control District v. Natural Resources Defense Council, Inc., No. 11-460, the Supreme Court held that the flow of water from a concrete-lined portion of a river channel — operated by the district — into unimproved downstream portions of the river that had no concrete lining does not qualify as a “discharge of pollutants” under the CWA.
The district operates a “municipal separate storm sewer system” (MS4), a storm-sewer conveyance system used to collect and channel storm-water runoff. Because storm water often is polluted, the CWA required the district to obtain a National Pollutant Discharge Elimination System (NPDES) permit before discharging storm water. When data from nearby monitoring stations showed that levels of pollutants allowed under the NPDES permit had been exceeded, the Natural Resources Defense Council filed a citizen suit against the district under the CWA.
The U.S. District Court granted summary judgment in favor of the flood control district, holding that there was insufficient evidence to establish that the district had discharged the pollutants detected at the monitoring stations. The U.S. Court of Appeals for the 9th Circuit reversed, however, holding that the district was liable for discharges from certain concrete-lined portions of the river — over which it exercised control — into downstream portions of the river that had no concrete linings. Although the water already contained pollutants when it entered the district’s MS4, the 9th Circuit determined that the CWA “does not distinguish between those who add and those who convey what is added by others — the [CWA] is indifferent to the originator of water pollution.”
The Supreme Court reversed, holding that when polluted water flows from one portion of a water body to another portion of a water body, as here, with the river channels, there is no "discharge of pollutants" within the meaning of the CWA. This conclusion flowed from the text of the CWA, which defines "discharge of a pollutant" to mean the "addition" of any pollutant to navigable waters from any source, and from applicable Supreme Court precedent, which held that discharges occur under the CWA only if water is transferred between "meaningfully distinct water bodies." Employing a tangible analogy, the Supreme Court explained: "[I]f one takes a ladle of soup from a pot, lifts it above the pot, and pours it back into the pot, one has not ‘added' soup or anything else to the pot."
Impact of Decision
The Supreme Court’s ruling clarifies that the flow of water between portions of the same appreciable water body, and specifically through a man-made portion of a waterway into a natural portion of the same waterway, does not qualify as a discharge of pollutants and does not require an NPDES permit. The court’s decision may also be cited in support of those arguing for more narrow parameters of liability for operators of MS4 systems, or owners or operators of other waterways or water bodies. Taking the ruling one step further, the decision may even fuel argument over how the term “discharge” should be defined in the context of other environmental statutes, such as state water codes modeled after the federal act, or other major environmental statutes, such as the Comprehensive Environmental Response, Compensation, and Liability Act.
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