Description: Streams where populations of New Zealand Mudsnails have been confirmed. Created as a featureclass and linear event table based on the current version of the National Hydrography Dataset (NHD).
Copyright Text: Jenifer Parsons, Washington Sate Department of Ecology
Description: Watersheds where populations of the New Zealand mudsnail (Potamopyrgus antipodarum) have been found or are likely to be found due to proximity to known populations. Based on HUC12 WBD Watersheds from USGS.
Description: Rivers 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.