How wet must a wetland be to have federal protections in post-Sackett US?

In 2023, the US Supreme Court’s majority ruled
in Sackett v. Environmental Protection
Agency that only wetlands that are “indistinguishable” from
federally protected waters “due to a continuous surface connection” are
federally protected. This study estimates the potential impact of
interpretations of the ruling on federal wetlands protections, using a
qualitative measure of wetland “wetness” as a proxy for the new
requirement. An estimated area ranging from ~17 million acres (19%) to
nearly all 90 million acres of nontidal wetlands in the conterminous
United States could be without federal protections, and variability in
state protections creates hotspots of risk. The high-level estimates
provided here represent a first step toward understanding the long-term
impacts of Sackett v. Environmental Protection
Agency on federal wetlands protections and highlight the uncertainty
introduced by the ruling.