The Environmental Protection Agency describes wetlands as those areas inundated or saturated by surface or groundwater and having a prevalence of vegetation typically adapted for life in saturated soil conditions. Those of us in South Louisiana can definitely agree on that assessment. Interestingly enough, the Clean Water Act identifies it navigable waters.

The recently released Clean Water Rule, has addressed the definition of navigable waters with a keen eye on what it means to be a wetland. The EPA says in the announcement that it is in part to refine the 3 Supreme Court decisions which have thrown wetland protections into question for 60 percent of the nation’s streams and millions of acres of wetlands. So what are those questions and how have they formed the bases for the Rule?

In the 1985 US v. Riverside Bayview Homes, 474 US 121 (Riverside) decision, the Court first entertained the idea of “significant nexus”. The case arose out of the Army Corps of Engineers filing suit under CWA to enjoin Riverside Bayview Homes from filling in wetlands, “characterized by the presence of vegetation that requires saturated soil conditions for growth and reproduction”. The 80 acres of marshy land was the property of Bayview Homes and was adjacent to a body of navigable water. The Corps used CWA’s clause prohibiting discharge of fill materials into “navigable waters” without a permit. The Court reasoned that adjacent wetlands are “inseparably bound up” with the waters to which they are adjacent because they blend into them. By doing so, the Court upheld the inclusion of adjacent wetlands in the regulatory definition of “waters of the United States” and deferred to the Corps’ ecological judgment.

Next came Solid Waste Agency of Northern Cook County v US Army Corps of Engineers, 531 US 159 (2001) (SWANCC). A consortium of Chicago municipalities chose an abandoned sand and gravel pit as a solid waste disposal site. Because the excavation trenches had become permanent and seasonal ponds, they contacted the Corps to determine whether a landfill permit was required. The Corps attempted to expand its jurisdiction over navigable waters under the “Migratory Bird Rule” which would extend intrastate wasters that provide habitat for migratory birds. The Court held that such an extension exceeded the authority granted to the Corps under CWA, but explained the concept of a “significant nexus” which had informed the Court’s decision in Riverside. The fact that the wetlands in Riverside were adjacent to open water was very different from the isolated ponds in SWANCC. And ultimately, the text of the statute would not support extending jurisdiction to ponds not adjacent to open water.

Finally, came the unanimous decision in Rapanos v United States, 547 US 715 (2006) (Rapanos). Rapanos involved four Michigan wetlands lying near ditches, man-made drains that eventually emptied into traditional navigable waters, defined in part as relatively permanent bodies of water. The Court determined that “waters of the United States” encompasses some waters that are not navigable in the traditional sense. This was based on Riverside’s rationale that “the evident breadth of congressional concern for protection of water quality and aquatic ecosystems.” However, the critical factor in determining the CWA’s coverage is whether a water has a “significant nexus” to downstream traditional navigable waters such that the water is important to protecting the chemical, physical, or biological integrity of the navigable water. As such, the Court rightly reasoned that the only plausible interpretation of “the waters of the United States” does not include channels through which water “flows intermittently or channels that periodically provide drainage for rainfall”. Thus any other definition would be arbitrary or capricious under Chevron and would not be permitted.

The new Clean Water Rule attempts to provide a cohesive rule consistent with the previous decisions and based on current science. It hinges on the concept of “significant nexus” and evaluates wetlands on an individual basis whether in- or outside of the floodplains.