In February 2017, the Trump administration directed the Environmental Protection Agency (EPA) and the Assistant Secretary of the Army for Civil Works (Assistant Secretary) to revise the definition of Waters of the U.S. (WOTUS). The definition is used to determine which streams, rivers, lakes, coastlines, and wetlands are protected from draining and filling under the Clean Water Act. Due to a combination of subsequent rule makings and court challenges, two definitions are currently used in the United States. The EPA and Department of Army published their proposed rule with a new definition of WOTUS in December 2018 to replace both of the currently used definitions. The new proposed rule would remove many waters and wetlands from Clean Water Act protection. There was a clear need for analytical materials, such as a digital map of different watersheds in the U.S. that shows which waters and wetlands are protected and which are not protected under these three scenarios. Such a resource could help elected officials, policy makers, and the public understand which waters are currently protected, as well as the extent and impact of the proposed changes, so they can comment on the proposed rule and plan for potential future changes in the extent of waters protected under the Clean Water Act.
With grant funding from the Hewlett Foundation, GeoSpatial Services (GSS) created a geospatial model that predicts the spatial extent of federally protected wetlands and waterways under three different protection scenarios. The methods and communication of results were guided by a project advisory committee made up of science and legal professionals. The results of the analyses show that narrowing the scope of federally protected waters would significantly reduce the number of streams, wetlands, and wetland acreage protected by the Clean Water Act, leading to a potential loss of benefits provided by wetlands that would no longer be protected under the Clean Water Act. These benefits include water quality protection, floodwater attenuation, fish habitat, and wildlife habitat. The methods and results of this work can be found in a final report and in a story map developed with Esri technology.