Elevation-Derived Hydrography in the Upper Shawsheen River Basin, Massachusetts

The U.S. Geological Survey (USGS), in cooperation with the Air Force Civil Engineer Center (AFCEC), has compiled Geographic Information Systems (GIS) datasets. The spatial data layers provided in this data release are hydrography data derived from high-resolution lidar digital elevation models (DEM). They include a hydroline polyline shapefile used to hydro-enforce the high-resolution lidar DEM; a stream network centerline polyline shapefile derived from the hydro-enforcement that shows stream location; a sub-basin polygon shapefile derived from the hydro-enforcement representing watershed areas for all stream network centerline polylines; a flow direction raster, predicting the direction of flow based on direction of steepest drop; and a flow accumulation raster, predicting the number of upstream cells flowing into each one-meter cell. Field verification was conducted for locations where the high-resolution lidar digital elevation models were unclear on hydraulic connection. Photographs were captured to confirm the conveyance of flow. The datasets are provided in separate child items.