On Jan. 8, 2013, the U.S. Supreme Court unanimously held that flow from an improved portion of a waterway into an unimproved portion of the same waterway—even if polluted—does not qualify as “discharge of pollutants” under the Clean Water Act (CWA). Although this case arises in the context of a municipal separate storm sewer system (MS4), it has major implications for dam owners everywhere. The case reaffirms evolving doctrine that dams are not point sources requiring National Pollutant Discharge Elimination (NPDES) permits per Section 402 of the CWA.
In Los Angeles County Flood Control District v. Natural Resources Defense Council, environmental groups brought a CWA citizen suit against the District for violating the terms of the District’s NPDES permit to operate the MS4 facilities. It was undisputed that water quality standards had repeatedly been exceeded for a range of pollutants, as measured at the District’s monitoring stations in the Los Angeles and San Gabriel rivers. The District collected storm water in concrete channels before discharging back to the river, and the monitoring stations were within the concrete channels. It was also undisputed that many other upstream parties contributed to the contamination.
Plaintiffs argued that since the monitoring stations were within the control of the District, the District had responsibility for meeting standards. But that was not the issue for the Court. Instead, the Court focused on whether a “discharge of pollutants” occurs when polluted water flows from one portion of a river, through an engineered improvement, and then back again to the same river. The Court answered in the negative, citing its 2004 decision in South Fla. Water Management Dist., v Miccosukee Tribe. In Miccosukee, the Court held that pumping polluted water from one part of a water body to another part of the same water body is not a discharge of pollutants.
This decision should come as welcome news to dam and hydroelectric plant owners. Prior to Miccosukee and now LA County, the federal Courts of Appeal simply deferred to EPA judgment as to whether a dam could be said to “add” pollutants originating upstream when it passes them through penstocks or spillways to the river below. The Supreme Court, however, has firmly established a rule of law that CWA Section 402 is implicated only where the upstream and downstream river segments are “meaningfully distinct water bodies,” a condition that will rarely exist for in-river dams.