Jenifer ParsonsRivers and Lakes in Washington where known populations of New Zealand mudsnails (Potamopyrgus antipodarum) exist upstream or in the immediate watershed. Originally created from Washington Rivers polygon layer in 2010. Addtional polygons imported from NHDArea and NHDWaterbody beginning in 2014.ArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/089212753b2c4cba99dc49149d107f76_5engState of Washington Geospatial Open Data PortalPublicInvasive Species Areas of Extreme Concern: Waterbodies [Washington (State)]Web servicesWashington (State)Last Modified: 2025-12-29