The National Hydrography Dataset (NHD) is a comprehensive set of digital spatial data
that contains information about surface water features such as lakes, ponds, streams,
rivers, springs and wells. Within the NHD, surface water features are combined to form
"reaches," which provide the framework for linking water-related data to the NHD
surface water drainage network. These linkages enable the analysis and display of these
water-related data in upstream and downstream order.
The NHD is based upon the content of USGS Digital Line Graph (DLG) hydrography data
integrated with reach-related information from the EPA Reach File Version 3 (RF3). The NHD
supersedes DLG and RF3 by incorporating them, not by replacing them. Users of DLG or RF3
will find the National Hydrography Dataset both familiar and greatly expanded and refined.
While initially based on 1:100,000-scale data, the NHD is designed to incorporate and
encourage the development of higher resolution data required by many users.
Hydrology Unit Data Sources
The National Dataset is available for no charge at http://nhd.usgs.gov/ . Technical documentation and tools are also available at that location. The data is in a format called NHDinARC, and there are tools for using that format as well as converting the data into Shapefile format.
For additional information regarding this Web page, contact Deb Southworth Green , in the Division of Information Resources and Technology Management, at Deb_Green@fws.gov
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Keywords=GIS, data, watersheds, huc, hydrologic, units, NHD
Last Modified January 03, 2001 03:26 PM