The public, private, and tribal forests of the United States are crisscrossed by thousands of miles of logging roads. When it rains or snow melts, the runoff from those roads can be environmentally harmful, depositing large amounts of sediment and other pollutants into streams and rivers. How, under the federal Clean Water Act (CWA), should logging road runoff be addressed? On March 20, 2013, the Supreme Court answered a key aspect of that question. In Decker v. Northwest Environmental Defense Center , the Court held that EPA had permissibly construed a prior version of its Industrial Stormwater Rule to exempt stormwater runoff from logging roads that is channeled—that is, collected in ditches, culverts, or other channels—from the discharge permit scheme in the Clean Water Act (CWA). The decision below, by the Ninth Circuit, was reversed. That court had held that when water running off logging roads is channeled, CWA regulations require that a discharge permit be obtained. The Ninth Circuit decision had prompted immediate reaction in Congress, which enacted legislation barring EPA from requiring discharge permits for logging road runoff until September 30, 2013, and now has enacted permanent legislation to that effect (the 2013 farm bill, H.R. 2642 , P.L. 113-79 ). As a measure of the interest in the case, 24 states and many county organizations and forestry trade associations filed amicus briefs asking the Supreme Court to reverse the Ninth Circuit decision. This report gives the statutory and regulatory background of Decker , describes the Supreme Court decision, lays out some legal and programmatic implications of the decision, and describes congressional response. Clean Water Act . Congress enacted the modern version of the CWA in 1972, adding regulatory teeth to a statute first enacted in 1948. As amended in 1972, the CWA prohibits the "discharge of any pollutant," defined as "any addition of any pollutant to navigable waters from any point source"—unless, among other exemptions, one has a discharge permit. Discharge permits are issued under the National Pollutant Discharge Elimination System created by CWA Section 402, hence are known popularly as NPDES permits. NPDES permits are issued by EPA or, far more often, by a state agency under an EPA-approved state program, and impose effluent standards and other conditions on the discharger. To reiterate, NPDES permits are required only for point sources of water pollution, defined by the CWA as "any discernible, confined, and discrete conveyance, including … any pipe, ditch, channel.... " They are not required for "nonpoint sources" of pollution, which the CWA does not define though the term is understood to mean pollution that comes from many diverse sources caused by rainfall or snowmelt moving over and through the ground. The legal issue in the Decker litigation is whether logging road runoff channeled through ditches, culverts, or channels falls under the point source definition, and, if so, whether the resulting NPDES permit requirement is circumvented by any other provision in the CWA or EPA regulations. EPA's Silvicultural Rule . In 1976, EPA attempted by rule to distinguish silvicultural activities deemed silvicultural point sources subject to NPDES permits from silvicultural nonpoint sources not subject to such permits, but rather governed by state management programs. In this "Silvicultural Rule" (last amended in 1980), EPA defined the phrase "silvicultural point source" as: any discernible, confined, and discrete conveyance related to rock crushing, gravel washing, log sorting, or log storage facilities which are operated in connection with silvicultural activities and from which pollutants are discharged into waters of the United States. The term does not include non-point source silvicultural activities such as nursery operations, site preparation, reforestation … thinning, prescribed burning, pest and fire control, harvesting operations, surface drainage, or road construction and maintenance from which there is natural runoff . As is evident, the rule lists four silvicultural activities that EPA deems point sources (rock crushing, gravel washing, log sorting, and log storage facilities) and determines that stormwater runoff from roads and road maintenance is a nonpoint source discharge outside the permitting process. Though the italicized phrase does not explicitly extend to road runoff that is channeled before reaching jurisdictional waters, that is how EPA interpreted it in the Decker litigation. Clean Water Act Stormwater Amendments and EPA Regulations. The final item of pertinent law was added in 1987 when Congress, recognizing the special difficulties posed by stormwater runoff, amended the NPDES section of the CWA. New CWA Section 402(p) established a two-phase process for regulating stormwater discharges from point sources—commonly called Phase I and Phase II. Phase I requires NPDES permits for five listed categories of stormwater discharges, including "[a] discharge associated with industrial activity." EPA defines "discharge associated with industrial activity" to include: [f]or the categories of industries identified in this section … stormwater discharges from … immediate access roads … used or traveled by carriers of raw materials.... The following categories of facilities are considered to be engaging in "industrial activity" …: … Facilities classified as Standard Industrial Classifications 24 [lumber and wood products] (except 2434). Phase II directs EPA to conduct a study of stormwater discharges not covered by Phase I, and then "establish a comprehensive program to regulate such designated sources." The program "may include performance standards, guidelines, guidance, and management practices and treatment requirements, as appropriate." Phase II is a more flexible regulatory authority than Phase I: EPA is authorized to require NPDES permits for discharges under Phase II, but is not required to do so. The Decker case, originally styled Northwest Environmental Defense Center v. Brown , was filed in federal district court by NEDC against Oregon state officials and timber companies, under the CWA citizen suit provision. The suit claimed that the defendants violated the CWA by not obtaining NPDES permits for stormwater runoff that flows from two state-owned logging roads in the Tillamook State Forest into ditches, culverts, and channels and thence into streams and rivers. NEDC argued that sending the runoff through such ditches, culverts, and channels creates point sources of pollutant discharge, triggering the NPDES permit requirement, and that nothing in the CWA exempts logging road runoff categorically. In 2007, the district court dismissed the environmental group's complaint on the ground that under EPA's Silvicultural Rule, runoff from logging operations does not constitute a point source. As a nonpoint source, such runoff required no NPDES permit. On appeal, the Ninth Circuit in 2011 reversed. On a preliminary jurisdictional issue, the court found the suit to have been properly filed in the district court as a citizen suit. On the merits, the court rejected the state's and timber companies' two arguments—that EPA's Silvicultural Rule, as construed by EPA, exempts logging road runoff collected in ditches, culverts, and channels from the NPDES permit requirement, and, alternatively, that the 1987 stormwater amendments to the CWA exempt such discharges. In short, channeled logging road runoff, in the Ninth Circuit's view, requires a NPDES permit. On March 20, 2013, with the case renamed Decker v. Northwest Environmental Defense Center , the Supreme Court reversed again on the permit question. Before the Court was the version of EPA's Industrial Stormwater Rule addressed by the decisions below—that is, before the agency amended it on November 30, 2012, three days prior to oral argument. The Court held that EPA's interpretation of the rule to exempt discharges of channeled stormwater runoff from logging roads from the NPDES permit scheme was a permissible one. At the outset, the Court brushed aside two jurisdictional issues. First, the Court agreed with the Ninth Circuit that use of the CWA citizen suit provision was proper here. NEDC's claim, in the Court's view, sought to enforce its permissible reading of the Silvicultural Rule, and citizen enforcement is precisely the function of citizen suits. The suit was not an effort to challenge the rule, initial jurisdiction over which lies solely in the circuit courts of appeal. Second, the Court found the claim not to have been mooted by EPA's November 2012 amendment to the rule. A live controversy still existed, ruled the Court, as to whether the timber companies might be held liable for unlawful discharges under the pre-amendment version of the rule before the Court. On the merits, recall that the CWA requires timber companies to have NPDES permits for channeled logging road runoff only if the discharges are, in the words of the CWA, "associated with industrial activity"—as that phrase is defined in EPA's Industrial Stormwater Rule. EPA had long interpreted this rule definition not to reach logging road runoff, and the Supreme Court concluded 7-1 in Decker that EPA's interpretation of its rule was a permissible one. The rule's references suggested to the Court that its natural reading was confined to traditional industrial buildings, and so did not extend to logging operations. Moreover, EPA had espoused this reading for a long time; it had not been adopted recently in response to this litigation. In light of these factors, the Court viewed the precept that courts owe deference to agency interpretations of their own rules as applying in full force. Finally, the state of Oregon had invested much effort in developing best management practices for stormwater runoff from logging roads, so EPA, as the Court saw it, could reasonably have concluded that further federal regulation would be unnecessary. Accordingly, the Supreme Court reversed the Ninth Circuit and remanded the case. Aftermath.