On April 21, 2014, the U.S. Environmental Protection Agency and Army Corps of Engineers issued a proposed rule defining “waters of the United States” under the Clean Water Act (CWA). 79 Fed. Reg. 22,188 (proposed Apr. 21, 2014) (to be codified at 33 C.F.R. pt. 328, 40 C.F.R. pts. 110, 112, 116). Should this change become final without substantive revision, the agencies would dramatically shift the foundation on which they base jurisdiction over the various types of waters. Although this change would have a negligible practical impact on jurisdictional determinations for many types of waters, it has the potential for significant changes with regard to more isolated or remotely connected waters.
The agencies estimate in their economic analysis of the proposed rule that 100 percent of streams and wetlands would be jurisdictional and that 17 percent of “other waters” (primarily adjacent waters) evaluated under the agencies’ current practices (but for which 0 percent were determined to be jurisdictional during the 2009–2010 baseline used by the agencies in their analysis) would be jurisdictional. The agencies note in their analysis that the proposed rule would also include certain more remote or isolated waters that currently are not even considered or evaluated, such as prairie potholes, vernal pools, playa lakes, and Carolina/Delmarva inland bays that alone or in combination have a significant nexus to other jurisdictional waters. Although practitioners question whether the agencies have accurately evaluated the potential impacts (or where the agencies will ultimately draw the line), the agencies estimate that 5 to 10 percent of these additional waters would also be considered jurisdictional.U.S. Environmental Protection Agency, Economic Analysis of Proposed Revised Definition of Waters of the United States (Mar. 2014).