On April 21, 2020, the U.S. Environmental Protection Agency (EPA) and Army Corps of Engineers (USACE) published the Navigable Waters Protection Rule defining the federal government’s Clean Water Act (CWA) permitting jurisdiction by streamlining what waters are considered “waters of the United States.” The CWA’s permitting authority applies to “navigable waters,” which was previously defined without explanation as “waters of the United States.” This omission led to decades of litigation, regulatory reversals, and divergent judicial interpretation.
The Navigable Waters Protection Rule is the second step in the Trump Administration’s two-part effort to define the scope of waters of the United States. In step one, on October 22, 2019, the EPA and the USACE repealed the Obama Administration’s 2015 Clean Water Rule: Definition of “Waters of the United States.” The 2015 rule defined waters of the United States expansively to include even minor isolated streams and wetlands, as long as there was a “significant nexus” between those waters and larger “navigable waters” such as rivers, lakes, or the ocean.
Step two, the Navigable Waters Protection Rule itself, eliminates the case-specific application of the 2015 rule’s “significant nexus” test by defining waters of the United States to include four categories of waters. These categories are (1) territorial seas and traditional navigable waters; (2) tributaries of such waters; (3) certain lakes, ponds, and impoundments of jurisdictional waters; and (4) wetlands adjacent to other jurisdictional waters.
In addition to defining what is a water of the United States, the Navigable Waters Protection Rule clarifies what is not a water of the United States. Critically, the rule provides that groundwater is not a water of the United States and that groundwater connections are an insufficient basis upon which to assert CWA jurisdiction. The rule also explicitly excludes ephemeral features that flow only in direct response to precipitation, diffuse stormwater runoff, ditches, prior converted cropland, artificially irrigated waters, artificial lakes, water-filled depressions constructed or excavated incidental to mining or construction activity, and water-filled pits excavated for the purpose of obtaining fill, sand, or gravel.
Through the Navigable Waters Protection Rule, the EPA and the USACE seek to end the decades-long tumult surrounding permitting jurisdiction under the CWA. However, the rule will face multiple significant legal challenges brought by states and environmental groups that may ultimately perpetuate the regulatory uncertainty surrounding the definition of “waters of the United States.”