Network Water Inventory
Water Body Location and Classification
To obtain the locations of hydrographic features, the Service-wide Inventory and Monitoring Program and the Water Resources Division have been partnering with the U.S. Geological Survey, states, and other federal agencies to create the high-resolution (1:24,000; 1:63,360 in Alaska) National Hydrography Dataset (NHD) (http://nhd.usgs.gov/) for 8-digit hydrologic units/subbasins containing national park units. NHD is a feature-based geographic database that interconnects and uniquely identifies all the stream segments (or "reaches") that comprise the nation's surface water drainage system. 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.
The effort to produce NHD for parks began in late FY03 following a priority order list established in concert with regional GIS coordinators. A significant component of this effort has been to incorporate hydrographic data into NHD whenever a park possesses better hydrographic data in their GIS than what is typically used to build the NHD. All NPS units had high resolution NHD available by the end of 2006. Consistent Service-wide hydrographic statistics are being generated from the NHD to support NPS strategic planning and GPRA goals. Although NHD provides an inventory of most hydrographic features, it does not furnish adequate data for wetlands.