National Hydrography Dataset (NHD)

Tucker, Dean

The National Hydrography Dataset (NHD) contains features such as lakes, ponds, streams, rivers, canals, dams and streamgages. These data are designed to be used in general mapping and in the analysis of surface-water systems. To obtain the locations of hydrographic features in digital form, the I&M Program and the NPS Water Resources Division (WRD) partnered with the U.S. Geological Survey (USGS), states, and other federal agencies to create the high-resolution (1:24,000, 1:63,360 in Alaska ) National Hydrography Dataset for 8-digit hydrologic units/subbasins containing national park units. The NHD is a feature-based geographic database that interconnects and uniquely identifies all the stream segments (or "reaches") that comprise surface water drainage systems. Included in NHD are hydrographic features such as streams, rivers, canals, lakes, ponds, reservoirs, springs, wells, swamps, and other hydrologic phenomena that appear on the typical USGS 7.5 minute (15’ Alaska) topographic map series. A significant component of this inventory entailed incorporating park hydrographic data into NHD whenever a park had better data available than what was typically used to build the NHD.