Spatial data layers of stream crossing point locations, cross-section polyline, centerline polyline, and bank polyline shapefiles have been developed for selected stream crossings in the Squannacook River basin, Massachusetts. The spatial data and calculated attribute values are model input data for U.S. Army Corps of Engineer’s Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic models. The stream crossing point locations were derived from the North Atlantic Aquatic Connectivity Collaboration (NAACC) database. The stream channel cross-sections, centerlines, and bank polylines were derived using automated methods in a Geographic Information System (GIS) using ArcGIS Pro and Python programming language. The polyline shapefiles are Z-enabled and have elevation data derived from Light Detection and Ranging (lidar) Digital Elevation Models (DEM) for Z-coordinate vertex values in units of feet. The polyline shapefiles are also M-enabled and have profile stationing values for the M-coordinate vertex values in units of feet. The automated GIS processes delineated a series of stream channel cross-sections along lidar-derived stream centerlines and have stream channel bathymetry estimated from Massachusetts bankfull channel geometry equations (Bent and Waite, 2013). The bankfull equations were also used to derive stream bank polylines. This data release contains the following shapefiles in the Spatial_Data_Layers.zip file: 1. Stream_Crossing_Locations.shp - Esri point shapefile derived from the NAACC stream crossing database. 2. Stream_Crossing_Watersheds.shp - Esri polygon shapefile of lidar-derived watershed boundaries that estimate the upstream drainage area for each stream crossing ___location. 3. Model_Cross_Sections.shp - Esri Z- and M-enabled polyline shapefile of the cross-section data used for hydraulic model input. 4. Model_Flowpaths.shp - Esri Z- and M-enabled polyline shapefile of the stream centerline and stream bank line data used for hydraulic model input.
References: Bent, G.C., and Waite, A.M., 2013, Equations for estimating bankfull channel geometry and discharge for streams in Massachusetts: U.S. Geological Survey Scientific Investigations Report 2013–5155, 62 p., http://dx.doi.org/10.3133/sir20135155