A significant effect of the definition of “waters of the United States” (WOTUS) in the Navigable Waters Protection Rule (NWPR) issued by the Trump administration is eliminating federal jurisdiction over ephemeral streams.

Surface Water in Direct Response to Precipitation
The Code of Federal Regulations defines “ephemeral” as “surface water flowing or pooling only in direct response to precipitation (e.g., rain or snow fall).” 33 CFR 328.3(c)(3) The NWPR says “non-jurisdictional waters,” which are “not ‘waters of the United States’” include “ephemeral streams, swales gullies, rills, and pools.”  33 CFR 328.3(b)(3)

Biden Administration’s Concern over Ephemeral Streams
A recent declaration of Jaime A. Pinkham, Acting Assistant Secretary of the United States Army for Civil Works, indicated the Biden administration has concerns regarding the decision “to categorically exclude all ephemeral waters.”  The declaration noted 76% of the determinations the government made between June 20, 2020 and April 15, 2021 (and thus under the NWPR) “were found to be non-jurisdictional” and many of the non-jurisdictional waters were “ephemeral” streams. The declaration noted the government has identified “333 projects that would have required Section 404 Permitting prior to the NWPR, but no longer do under the NWPR.”

Issue in Arid States
The changes due to the NWPR, according to the declaration, are “particularly significant in arid states.  In New Mexico and Arizona, for example, of over 1,500 streams assessed under the NWPR, nearly every one has been found to be a non-jurisdictional ephemeral resource, which is very different from the status of the streams” as assessed prior to the NWPR.

To see the Pinkham Declaration https://www.epa.gov/sites/default/files/2021-06/documents/2_conservation_law_found._d._mass._-_jaime_pinkham_declaration_final_signed_508c.pdf