Network attributes for the High Resolution National Hydrography Dataset (NHD) based initial 3D Hydrography Program Network

This dataset contains the initial 3D Hydrography Program (3DHP) flow network topology, which is based on the final High Resolution National Hydrography Dataset (NHD), and a set of mainstem river identifiers based on the Medium resolution NHDPlus Version 2 (NHDPlusV2). The 3DHP flow network topology and mainstem identifiers contained in this data release add two key pieces of information to the flow table of the National Hydrography Dataset:
1) at every junction, one and only one main upstream and downstream connection has been identified
2) every "in network" flowline has been assigned a mainstem identifier that places it into a hierarchy of rivers and drainage basins.
For description of 1 and 2 and additional background, see supplemental information.
Files included:
- HU6_mainstem_outlets.geojson
Outlet locations of six-digit hydrologic units along mainstem network.
- nhd_3dhp_conus_mainstems.zip
Zipped table in Comma Separated Values (csv) format containing NHD permanent identifiers and mainstem Uniform Resource Identifiers (URIs) for the Contiguous United States (CONUS).
- nhd_3dhp_conus_flownetwork.zip
Zipped csv table containing from / to NHD permanent identifiers (from flowline to flowline) and upmain / downmain attributes for CONUS.
- nhd_3dhp_conus_vpu_membership.zip
Zipped csv table containing NHD permanent identifiers and which Vector Processing Unit (VPU) they belong in.
- nhd_3dhp_oconus_mainstems.zip
Zipped csv table containing NHD permanent identifiers and mainstem URIs for areas Outside of the Contiguous United States (OCONUS).
- nhd_3dhp_oconus_flownetwork.zip
Zipped csv table containing from / to NHD permanent identifiers (from flowline to flowline) and upmain / downmain attributes for OCONUS.
-3dhp_flownetwork.zip
Zipped csv table containing from / to 3DHP identifiers (from flowline to flowline) and upmain / downmain attributes.
- nhd_3dhp_nonnetwork_mainstems.zip
Zipped csv table containing mainstem identifiers for features not included in the NHD flow table.
- nhd_final_registry.zip
Zipped csv table containing all expected flowlines from the final NHD -- excludes geometry.
- nhd_reachcode_mainstem.zip
Zipped csv table containing a mapping between mainstem identifiers and NHD reachcodes.
- nhd_3dhp_region_connections.zip
Zipped csv table containing connections between vector processing unit regions defined by four-digit hydrologic unit.
- nhd_3dhp_mainstem_summary.zip
Zipped csv table containing summary information about mainstems contained in nhd_3dhp_conus_mainstems.zip and nhd_3dhp_oconus_mainstems.zip.