What Is the National Hydrography Dataset?

The National Hydrography Dataset is managed by the U.S. Geologic Survey (USGS) to represent the nation-wide drainage network with features such as rivers, streams, canals, lakes, ponds, coastline, dams, and streamgages. This vector-based dataset can be used in everything from general mapping to complex analyses of surface water systems.

Wrangell - St. Elias, AK

This project is a collaborative effort between the Alaska Region of the National Park Service (NPS) and GSS to extend previously developed NHD editing protocols to accommodate wetlands and other Value Added Attributes (VAA) in the data development process. The processes assisted staff of the Alaska Region GIS Team by providing a set of data development protocols that are compliant with both AKHydro and USGS NHD spatial data formats and extend the ability of NPS to capture additional hydrographic features and characteristics associated with traditional NHD data elements (i.e., streams, rivers and lakes). The capture of these additional features provide for a much more comprehensive hydrographic database for ongoing mapping efforts (e.g., update U.S. Topo production) and set the stage for enhanced modelling and analysis capabilities including migration to the USGS NHDPlus data model. 

Matanuska - Sustina, AK

In the fall of 2013, The Nature Conservancy (TNC) initiated a hydrographic mapping and analysis program in the Matanuska-Susitna (Mat-Su) Basin using newly available data to map all lakes, rivers and streams to a level of quality and technical specification suitable for ingestion into the USGS NHD. This project improves the National Hydrography Dataset component of The National Map by updating linear (1D) and polygon (2D) features for the NHD and ingesting 1D and 2D feature updates into the NHD for the 16,309,920 acre (25,484 sq. mile) Mat-Su Basin. 

The Mat-Su Basin hydrographic mapping program consisted of two phases; a modeling phase and a validation phase. The modeling phase employed newly available LiDAR and IfSAR elevation data to create an elevation-derived, synthetic network of hydrologic flowlines, or streams, in the Mat-Su Basin.  The validation phase consisted of an independent photogrammetric review of modeled streams coupled with field observations to validate the final hydrography and ensure that the mapped features best reflected actual ground conditions. Once validated through these processes, the entire Mat-Su stream network was conflated to the USGS NHD from Alaska Hydro data schema following USGS specifications for 1:24,000 scale mapping and was chosen as the first area in Alaska for migration to USGS NHDPlus.

Kenai Peninsula, AK

The Kenai Watershed Forum (KWF) tasked GSS with the completion of a comprehensive review and validation of both the one dimensional (1D or linear features) and two dimensional (2D or polygon features) NHD data for two hydrologic unit code (HUC) sub-basins (HUC-8 19020301 and HUC-8 19020302) on the Kenai Peninsula, Alaska.  These two sub-basins cover approximately 4,708,533 acres of land stretching from the Turnagain Arm in the north to the City of Homer in the south.

The purpose of this project was to review, validate and, where necessary, update the Kenai Peninsula NHD in order to meet the national quality standards identified by the USGS. This validation process is possible because up-to-date, large scale imagery and digital elevation data is now available for the Peninsula through the mapping efforts of the Kenai Borough, the US Fish and Wildlife Service (USFWS) and the Alaska Spatial Data Mapping Initiative (SDMI).

These watersheds are vital to not only the natural landscape and wildlife that exists there, but the Kenai is well known as a premier sport and commercial fishing destination. It is important to protect and enhance the native fish and aquatic resources of this region for both its natural beauty and its benefit to the economy. The NHD is useful for contributing to the KWF’s planning efforts for habitat conservation and restoration. With its lakes and streams mapped the KWF and its partners can use this data to better assess where stream features may be affected negatively through land use. This data can also be used to inform policy makers of conditions affecting the watersheds on the Kenai Peninsula.