The fluid definition of the ‘waters of the United States’: Non-uniform
effects of regulation on US wetland protections
Abstract
Recent revisions to the definition of the “waters of the United
States” (WOTUS) have considerably altered how wetlands are federally
regulated under the Clean Water Act. The two most recent modifications
to WOTUS, the Clean Water Rule (CWR) and the Navigable Waters Protection
Rule (NWPR), represent two opposing approaches to the federal wetland
policy. Despite their implementation, the impacts of these rules on the
regulation of wetlands have as of yet been poorly characterized at broad
spatial scales. Using New York State (NYS) as a case study, we evaluated
the jurisdictional statuses of more than 373,000 wetlands under the CWR
and the NWPR to assess the landscape-scale effects of WOTUS
re-definitions. We found that statewide and within each of NYS’s
hydrologic regions, the NWPR protects fewer wetlands and less total
wetland area than the CWR. The efficacy of the two regulations varied
considerably in space across NYS, highlighting the need for
comprehensive, nationwide assessments of wetland policy outcomes. We
also observed that both rules produced non-uniform patterns in
jurisdiction across a range of landscape positions and wetland sizes,
preferentially protecting large wetlands close to the stream network.
This effect was particularly pronounced under the NWPR, which excludes
all geographically isolated wetlands from protection. Our findings in
NYS emphasize the existence of unique patterns in protected wetlands
across spatial scales, highlighting the value in applying geospatial
analyses to evaluate environmental policy.