A Generalized Hydrologic Stream Network (GenNet) of the Conterminous United States

A generalized hydrologic stream network (GenNet) consisting of 263,494 generalized flowlines, inclusive of coastline and terminating flow paths, was constructed for the conterminous United States (CONUS) to support efficient dynamic modeling of nutrient loads, streamflow, and downstream transport of other contaminants in streams. GenNet was generalized from the base network E3NHDPlusV2_us, which is E2NHDPlusV2_us (Schwarz, 2019) with some addition/removal (AR) events--routed transfers that divert or remove water from one reach and add it to another--revised in the western United States. The base network was generalized while retaining specified points of interest (POIs) important to water quality and quantity modeling. In this application, POIs were defined for 12-digit hydrologic unit code (HUC12) watershed outlets, select waterbody inlets and outlets, diversions and AR events (including inter-basin transfers), and monitoring stations. GenNet delineates the network in both the upstream and downstream direction from specified POIs. This delineation process extends pathways to headwaters and breaks or re-factors long flowlines while ensuring no flowline is shorter than a specified threshold, which was set to 10 kilometers in this application. The resulting network includes hydrologic sequencing, flow direction attributes, and other variables necessary for hydrologic routing. Files in this data release allow for the re-creation or modification of GenNet and include (see ReadMe_GenNet.txt for content details):
1. Data table with summary GenNet attribute information.
2. Summary crosswalk table from E3NHDPlusV2_us to GenNet.
3. Geographic layers of GenNet flowlines, catchments, and waterbody geometries.
4. Computer processing scripts with instructions and data table copies used to make E3NHDPlusV2_us and GenNet.