U.S. Supreme Court Reverses Ninth Circuit and Reaffirms Water Transfer Precedent in Los Angeles County MS4 Clean Water Act Case

January 9, 2013

In a unanimous opinion issued January 8, 2013, the United States Supreme Court held that the flow of water from one portion of a navigable water through a concrete channel or other engineered improvement into an unimproved portion of the same water body does not constitute a “discharge of a pollutant” under the Clean Water Act (“CWA”).  Los Angeles County Flood Control Dist. v. Natural Res. Def. Council, Inc., No. 11–460 (Jan. 8, 2013). The case reaffirms existing Supreme Court precedent that no pollutants are “added” to a water body when water is merely transferred between different portions of the same water body. Attorneys from Downey Brand’s Environmental Law Practice Group filed amicus curiae briefs on behalf of the California State Association of Counties, the League of California Cities, and the National League of Cities, which advocated for the position, among others, adopted by the Supreme Court.

The CWA prohibits the “discharge of any pollutant” into waters of the United States except in compliance with a permit. 33 U.S.C. § 1311(a). The phrase “discharge of a pollutant” is defined as “any addition of any pollutant to navigable waters from any point source.” Id. § 1362(12). This case involved the Los Angeles County Flood Control District’s (“District”) municipal separate storm sewer system (“MS4”) – a drainage system that collects, transports and eventually discharges storm water into the Los Angeles and San Gabriel Rivers at numerous points. As required by the CWA and its implementing regulations, the District obtained a permit under the National Pollution Discharge Elimination System (“NPDES”) to authorize its MS4 discharges.

In 2008, two environmental groups filed a citizen suit against the District alleging that the discharges from the District’s MS4 exceeded the limits set in the District’s permit.  The plaintiffs relied on data from monitoring stations located in concrete-lined portions of the rivers controlled by the District for flood control purposes. The monitoring data showed that water flowing out of the channelized segments of the river contained pollutant levels in excess of the limits established in the District’s permit.

The United States District Court for the Central District of California granted summary judgment in favor of the District. The District Court found the evidence insufficient to conclude that the District’s MS4 was contributing to the detected exceedances, citing the fact that there were numerous entities other than the District discharging into the rivers upstream of the monitoring stations. The monitoring data alone, held the District Court, was insufficient to tie the detected exceedances to the District’s MS4.

The Ninth Circuit undertook a different approach and reversed. Like the District Court, the Ninth Circuit was unwilling to accept the monitoring data as proof of violations at any particular upstream outfall. According to the Ninth Circuit, however, a discrete discharge of pollutants occurred when the water detected at the monitoring stations “flowed out of the concrete channels” and entered natural or unimproved downstream portions of the rivers. See Los Angeles County Flood Control Dist., No. 11–460, slip op. at 3. Because the District exercises control over the concrete-lined portions of the rivers, the Court of Appeals found the District liable for the exceedances detected where the water exited those concrete channels. The implication of the Ninth Circuit’s ruling was that the District, by virtue of its control over the concrete-lined segments, was liable for exceedances detected in those segments regardless of whether they were caused by the District’s MS4 discharges or by discharges from the myriad of other upstream dischargers.     

The United States Supreme Court granted the District’s petition for certiorari in June, 2012, and heard oral argument on December 4, 2012. In its unanimous decision issued January 8, 2013, the Court summarily rejected the Ninth Circuit’s analysis.  Specifically, the Court found the Ninth Circuit’s ruling inconsistent with prior Supreme Court precedent which holds that the transfer of polluted water between “two parts of the same water body” does not constitute a discharge of pollutants for purposes of the CWA. See Los Angeles County Flood Control Dist., No. 11–460, slip op. at 3-4 (citing South Fla. Water Management Dist. V. Miccosukee Tribe, 541 U.S. 95, 109-112 (2004)). That precedent, reaffirmed here, derives from the CWA’s text which defines the term “discharge of a pollutant” to mean “any addition of any pollutant to navigable waters from any point source.” Id. According to the Supreme Court, “no pollutants are ‘added’ to a water body when water is merely transferred between different portions of that water body.”  Id., slip op. at 4.   

In reversing the Ninth Circuit’s judgment, the Court refused to consider the plaintiffs’ alternative argument that the exceedances detected at the monitoring stations were alone sufficient to establish the District’s liability. That issue, the Court explained, was not within the scope of its review. Id., slip op. at 5. Nor did the Court rule on other issues raised by some amici that MS4 operators are subject to best management practices rather than stringent effluent limitations, or that municipal storm water permits include a “safe harbor” that forgives violations of discharge limits when the municipality follows an iterative assessment and improvement process. Ultimately, the Court’s decision represents a meaningful, if not expected, reaffirmation of its precedent that there is no discharge of pollutants for purposes of the CWA when water simply flows from one portion of the water body to another.

Attorneys in Downey Brand’s Environmental Practice Group have extensive experience advocating on behalf of their clients in Clean Water Act cases. In addition to filing amicus curiae briefs before the Supreme Court in Los Angeles County Flood Control Dist., Downey Brand attorneys recently helped the City of Malibu litigate and settle a similar citizen suit filed by the same environmental plaintiffs.