Yesterday, we started our commentary series about the final WOTUS rule by taking advantage of the rule’s increased clarity to identify the waters that would always be considered jurisdictional. The rule’s definitions leave no doubt that certain waters will always be considered jurisdictional by EPA and the Corps. But there’s another group of waters that aren’t always jurisdictional by definition, but will most likely be so in practice.

As you’ll recall, the proposal’s structure was twofold: It identified waters that would always be considered jurisdictional, and then provided for a set of waters that would be considered jurisdictional on a case-by-case basis if they had a significant nexus to a traditionally navigable water. The final rule maintains this same approach.

The proposed rule, though, left open a big question: the scope of the “aggregation” component of the second (“significant nexus”) test. The rule considers waters to be jurisdictional under the significant nexus test if they have a significant nexus either alone or in aggregation with other “similarly situated” waters in the “region.”  The proposed rule asked for comment on how to define “similarly situated” and “region.” The final rule takes two different approaches to answering this question, and at least one will have a significant effect: The Administration has identified five types of wetlands that “are similarly situated and shall be combined, for purposes of a significant nexus analysis, in the watershed that drains to the nearest” traditionally navigable or interstate water or territorial sea. These are:

(A) Prairie potholes, located in the upper Midwest,

(B) Carolina bays and Delmarva bays, that occur along the Atlantic coastal plain,

(C) Pocosins, found predominantly along the Central Atlantic coastal plain,

(D) Western vernal pools, located in parts of California, and

(E) Texas coastal prairie wetlands, located along the Texas (and possibly western Louisiana) Gulf Coast.

In other words, if you intend to impact one such water, the agency will determine its jurisdictional status by examining the significance of the nexus to the downstream water of all such waters in the applicable watershed. While there’s some question as to how large the applicable watershed is (which we’ll explore in a later post), the answer isn’t important for now. That’s because the smaller the watershed is, the closer the affected waters are to the traditionally navigable water, and the farther away it is, the more waters will be aggregated to determine if impact to them is significant. In either situation, aggregating all these waters in the watershed is quite likely to result on a determination that impacts to them would be significant.

So, in short, this grouping of wetlands will, in practice, mean that most such waters will be determined to be jurisdictional, regardless of their size or isolation from the other jurisdictional waters described in the rule. Given the geographic expanse of this set of waters, this is a significant extension of the agencies’ jurisdiction.

That’s it for the easy answers. On Monday, we’ll start looking at the harder questions.