Valleys - US EPA Regions 1, 2, 3, 9 (2022) and 10 (2024)
Valleys, featured in the Valley Identification Tool, are locations that have a lower elevation than surrounding areas. EPA Region 1 GIS Center applied ArcGIS' Focal Statistics tool to the USGS 30-meter NED DEM to find places where elevations are significantly less than average. We then quantified population and wood …