In Los Angeles County Flood Control District v. Natural Resources Defense Council, Inc., No. 11-460, decided January 8, 2013, the United States Supreme Court unanimously held that the flow of water from an improved portion of a navigable waterway into an unimproved portion of the same waterway does not qualify as a “discharge of a pollutant” under the Clean Water Act (CWA).  The Court reversed a U.S. Court of Appeals for the Ninth Circuit decision holding that pre-polluted water originating from a navigable river and passing through a “man-made construction” into the natural river below is a “discharge of a pollutant” under the CWA.  The Ninth Circuit’s decision raised concerns for the hydropower industry because dams are man-made constructions in navigable waters that discharge water downstream, and the decision suggested, contrary to well-established precedent, that dams could become subject to National Pollutant Discharge Elimination System (NPDES) permitting under section 402 of the CWA. 

Van Ness Feldman authored an amicus brief for the hydroelectric industry urging the result reached by the Court.

The Los Angeles Flood Control District (District) operates a “municipal separate storm sewer system” (MS4), a complex flood-control and storm-sewer conveyance system used to collect and channel stormwater runoff originating from upstream municipalities.  The MS4 is subject to an NPDES permit that governs municipal stormwater discharges in Los Angeles County.  As required by the NPDES permit, the District owns and operates a number of mass emissions monitoring stations to test the quality of water passing through the MS4.  Neither the MS4 nor the monitoring stations within the system add pollutants to the water that is conveyed, yet water passing through the MS4 contains levels of pollutants exceeding those authorized by the NPDES permit.

Natural Resources Defense Council, Inc. commenced a citizen suit under section 505 of the CWA, alleging that water passing through the MS4 contains pollutant levels exceeding the limits allowed by the NPDES permit.  The district court granted summary judgment in favor of the District, holding that there was insufficient evidence to establish that the District had discharged the pollutants that were detected at the monitoring stations.  The Ninth Circuit, however, reversed.  Because the monitoring stations are located in “concrete channels” owned by the District and constructed for flood-control purposes, the court held that a discharge of pollutants occurs when water passing through these “man-made constructions” empties into the natural river downstream of the MS4, and the District is liable for those discharges. 

Although water already contained pollutants when it entered the District’s MS4, the Ninth Circuit found 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.”

In a five-page opinion by Justice Ginsburg, the Supreme Court reversed the Ninth Circuit’s decision.  The Court explained that under its decision in South Florida Water Management District v. Miccosukee Tribe, 541 U.S. 95 (2004), the transfer of polluted water between “two parts of the same water body” does not constitute a discharge of pollutants under the CWA.  The Court based its decision inMiccosukee on the plain language of the CWA, which defines “discharge of a pollutant” as “any addition of any pollutant to navigable waters from any point source.”  In this case, therefore, no pollutants are added to the water when the water simply flows from one portion of the water body to another through a concrete channel.  The Court held that “the flow of water from an improved portion of a navigable waterway into an unimproved portion of the very same waterway does not qualify as a discharge of pollutants under the CWA,” and reversed the Ninth Circuit’s decision as inconsistent with the Court’s holding in Miccosukee.

The Court’s decision preserves long-standing precedent that hydropower dams are generally not subject to NPDES permits.  Had the Ninth Circuit’s decision been affirmed, dam operators could have been required to obtain NPDES permits for releases of water, such as power-generation activities or spillway releases.  Because NPDES permits must be obtained every five years, this requirement could interfere significantly with Federal Energy Regulatory Commission-issued long-term licenses that already contain compliance requirements, including water quality conditions under section 401 of the CWA.  Los Angeles County Flood Control District clarifies that the flow of water through a man-made construction (such as a dam, penstock, and/or powerhouse) within the same waterway does not qualify as a discharge of pollutants and does not require an NPDES permit.