ORAL PRESENTER CO-AUTHORS: Joanne Kline, Conservation Strategies Group, Wisconsin's Green Fire; Nick Miller, The Nature Conservancy, Wisconsin's Green Fire TITLE: Mapping the impacts of the Sackett decision in Wisconsin : A risk assessment ABSTRACT: The US Supreme Court's "Sackett decision" in Sackett vs US EPA has dramatically undercut federal regulation of the nation's wetlands under the Clean Water Act. Fortunately, Wisconsin does have state-level protection of “non-federal wetlands.” We present here an estimate of the impact of the Sackett decision for federal regulatory protection of Wisconsin wetlands carried out by a Green Fire workgroup in collaboration with The Nature Conservancy. We estimate that 88% of Wisconsin's wetlands will no longer be federally regulated under the Clean Water Act. The estimate makes use of a wetland mapping database and functional assessment produced by WDNR and The Nature Conservancy called Wetlands by Design. Because that project included a statewide assessment of wetland function, we have also been able to conduct a risk assessment of the potential loss of public benefits these wetlands currently provide. We will share examples of how this risk analysis can provide a powerful tool to inform a wetland conservation response to the Sackett decision in Wisconsin. Discussion around the shape of that response will be the focus of a related working group session on Thursday at 10:40 am. This talk serves as one starting point for that discussion. BIO: Tom Bernthal served as the Wetland Assessment and Monitoring Coordinator for the Wisconsin Department of Natural Resources and retired in 2019. He led projects that ranged from the field-intensive plant surveys to GIS-based mapping of potentially restorable wetlands and a statewide functional assessment called Wetlands by Design. In retirement, he has been involved in Wisconsin's Green Fire and Friends of Pheasant Branch Conservancy.