June 28, 2007Client Alert

Corps Issues Guidance on Wetlands Jurisdiction

Last year, on June 19, 2006, the U.S. Supreme Court announced its decision in Rapanos v. United States.1 At issue in Rapanos was the reach of the Army Corps of Engineers’ ("Corps") jurisdiction under the Clean Water Act ("CWA") over traditionally non-navigable waters, such as wetlands or tributaries, as "waters of the United States."2 In response to the decision, on June 5, 2007, the Corps and the United States Environmental Protection Agency ("EPA") issued a joint memorandum to their respective agencies to provide guidance on determining CWA jurisdiction ("Guidance").

Congress enacted the CWA to "restore and maintain the chemical, physical and biological integrity of the Nation’s waters."3 The Guidance explains that the Corps and EPA will determine jurisdiction on either a categorical or case-by-case basis depending on the characteristics of the water body.4

Categorical Determinations

The Corps and EPA will categorically exercise jurisdiction over:

  • Traditional navigable waters
  • Wetlands adjacent to traditional navigable waters
  • Non-navigable tributaries of traditional navigable waters that are relatively permanent where the tributaries typically flow year-round or have continuous flow at least seasonally (e.g., typically three months)
  • Wetlands that directly abut such tributaries

The Corps and EPA will categorically NOT exercise jurisdiction over:

  • Swales or erosional features (e.g., gullies, small washes characterized by low volume, infrequent, or short duration flow)
  • Ditches (including roadside ditches) excavated wholly in and draining only uplands and that do not carry a relatively permanent flow of water

Case-by-Case Determinations

The agencies will determine jurisdiction over the following waters based on a fact-specific analysis to determine whether there is a significant nexus with traditional navigable water:

  • Non-navigable tributaries that are not relatively permanent
  • Wetlands adjacent to non-navigable tributaries that are not relatively permanent
  • Wetlands adjacent to but that do not directly abut a relatively permanent non-navigable tributary

The agencies will apply the significant nexus standard as follows:

  • A significant nexus analysis will assess the flow characteristics and functions of the tributary itself and the functions performed by all wetlands adjacent to the tributary to determine if they significantly affect the chemical, physical and biological integrity of downstream traditional navigable waters
  • Significant nexus includes consideration of hydrologic and ecologic factors

Categorical Jurisdiction is Established by Finding Adjacency Through the Continuous Surface Connection Test

When the Corps analyzes a water body under a categorical determination, "adjacency" is the key factor and finding a "continuous surface connection" is the test for adjacency. A wetland is adjacent if there is a continuous surface connection between the wetland and traditional navigable waters or a tributary of a traditional navigable water. If a continuous surface connection is present, then the wetland is adjacent, and jurisdiction will be asserted on that categorical basis. In addition, if a wetland fits under a categorical determination, a significant nexus case-by-case determination is not required.

Case-by-Case Jurisdiction is Established by Finding a Significant Nexus Through the Ecological Relationship Test

In other situations, whether a wetland is adjacent may be unclear. For example, the Corps and EPA may have difficultly determining whether a tributary is relatively permanent or whether a continuous surface connection is present between a wetland and a traditional navigable water. As a consequence, the Corps and EPA will decide jurisdiction on a case-by-case basis to determine whether the water body has a significant nexus with traditional navigable water.

To determine whether a significant nexus is present, the Corps and EPA will determine whether the tributary has a significant effect on the ecological relationship between the tributary and the wetlands in affecting the chemical, physical, and biological integrity of downstream traditional navigable waters. The Corps and EPA will assess the tributary’s flow characteristics and functions, with any functions performed by any other wetlands adjacent to that tributary. The ecological factors the agencies will examine include hydrological and physical characteristics, such as gauge data, historical records of water flow, ordinary high water mark, and sediment-sorting among others. However, the Guidance does not explain the weight that will be given to those factors or how they will be applied in determining a significant nexus.

The threshold for determining significant nexus under the Guidance is relatively low. The agencies will find a significant nexus is present if the tributary and its adjacent wetlands are likely to have an effect that is "more than speculative or insubstantial" on the chemical, physical, and biological integrity of a traditional navigable water.

The Corps and EPA explain that the Guidance is not legally binding on the Corps, EPA, or the regulated community and that it may not apply to a particular situation. Therefore, interested parties may raise questions about the appropriateness of the Guidance’s application to a particular situation. The EPA and Corps will consider whether the Guidance is applicable and complies with the statutes, regulations, and case law in a particular situation. The Corps districts are posting all approved jurisdictional determination forms for public review. In addition, the Corps and EPA will continually review the Guidance and jurisdictional determination forms for any necessary changes to "ensure nationwide consistency, reliability, and predictability."

The Role of the Corps and EPA

Because the Corps and EPA both exercise jurisdiction under the CWA, to facilitate cooperation the agencies issued a second memorandum explaining how they will work together in determining jurisdiction under the Guidance.5 This memorandum explains that interagency coordination is required for intra-state, non-navigable, isolated waters, and waters where a case-by-case significant nexus analysis is necessary. Interagency coordination is not required over traditional navigable waters and adjacent wetlands.

Effect of the Guidance on Wisconsin Waters

The Guidance is instructive as to how the Corps and EPA will address the jurisdictional questions, but will be of limited impact in Wisconsin. The Guidance does not expand the Corps’ jurisdiction over tributaries and wetlands beyond the limits set in previous U.S. Supreme Court decisions. Previously, the Corps exercised CWA jurisdiction over "isolated non-navigable intrastate waters" if the waters were inhabited by migratory birds, also known as "the Migratory Bird Rule." However, the U.S. Supreme Court decision in Solid Waste Agency of Northern Cook Cty. v. Army Corps of Engineers, ("SWANCC") limited CWA jurisdiction over these waters concluding they were not "waters of the United States" and thus not subject to the CWA.6 As a result, those waters also were not subject to water quality certification by the Wisconsin Department of Natural Resources ("WDNR") as the WDNR derived its authority from the federal authority. In response, the Wisconsin Legislature enacted Wis. Stat. § 281.36, which provides the WDNR with authority to require water quality certification for discharges of dredged and fill material to nonfederal wetlands.7

In sum, if a Wisconsin wetland or tributary fits under a categorical or case-by-case determination, then it will be subject to Corps and EPA jurisdiction under the CWA requirements. If not, then WDNR will still have authority over it in Wisconsin.

1 Rapanos v. United States, 547 U.S. ___, 126 S. Ct. 2208 (2006), available at

2 For more information, see the Michael Best's client alert on the Rapanos decision.

3 See 33 U.S.C. § 1251(a).

4 Guidance Memorandum and Bullet points, available at

5 Joint Implementation of Guidance, available at

6 531 U.S. 159 (2001), for more information, see Michael Best's Client Alert on the SWANCC decision.

7 For more information see Michael Best's article on the Wisconsin Legislature’s response to SWANCC.


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