On June 19, 2006, the U.S. Supreme Court ruled in the consolidated cases of Rapanos v. United States and Carabell v. United States (collectively Rapanos) that there are limits to the federal government’s authority to regulate “waters of the U.S.”, including wetlands, under the federal Clean Water Act (CWA). However, in its decision, the Court declined to define those limits, but rather left it to the U.S. Army Corps of Engineers (Corps) and the U.S. Environmental Protection Agency (EPA) to determine them given the broad guidance of the Court’s decision.

A little less than one year later, the Corps and the EPA published joint guidance regarding the scope of CWA jurisdiction over “waters of the U.S.” The new Rapanos guidance specifically directed the Corps to regulate activities within (a) waters that are traditionally navigable, (b) wetlands immediately adjacent to such waters, (c) relatively permanent tributaries of traditional navigable waters, and (d) wetlands that have a continuous surface connection to such tributaries.

For all other waters that are non-navigable and non-permanent tributaries to traditional navigable waters, the Corps would determine its CWA jurisdiction on a case-by-case basis using a new “significant nexus” analysis. As part of its analysis, the Corps would include wetlands that are adjacent to the tributary regardless of whether a surface hydrologic connection was present. In general, the “significant nexus” analysis would evaluate such tributary characteristics as volume and duration of flow, proximity to traditional navigable waters, and contribution of ecological function to traditional navigable waters.

Significantly, the new Rapanos guidance establishes that the Corps generally would not regulate swales or erosional features such as gullies or small washes with infrequent or short duration of flow. Nor would the Corps regulate ditches (including roadside ditches) excavated wholly in and draining only uplands, and that do not carry a “relatively permanent” flow of water (flow for at least 3 months during most years).

The Corps and the EPA have not yet finalized the Rapanos guidance, but plan to re-issue, revise, or suspend the guidance this spring after considering public comment and field experience with its implementation. Until then, the Corps is elevating many jurisdictional determinations from district offices to federal headquarters in Washington D.C. to assess consistency with the current guidance. This has resulted in longer than usual time-frames for processing CWA permits to work within “waters of the U.S.” Once the Corps and EPA implement the final guidance, we expect the time to process these permits to be reduced substantially.

Be aware that even if the Corps does not assert federal jurisdiction over a particular wetland or stream, it is often the case that local land use regulations, as well as state regulations such as RCW 20.98 will regulate activities within that wetland or stream.

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