Project Summary:

Topographically-based catchments will be delineated for all stream-reach segments of the National Hydrography Dataset (NHD) within the entire conterminous United States. The NHD is a digital hydrographic dataset produced by the USGS, in cooperation with the U.S. Environmental Protection Agency (USEPA), that shows streams, lakes, ponds, and wetlands for the Nation at an initial scale of 1:100,000. This effort is being supported by the USEPA and USGS and is intended to benefit a wide variety of water-quality and stream-flow studies across the nation.

The catchment-delineation technique is the same as that developed for use in the New England SPARROW model. The New England SPARROW model was the first to utilize the detail of the National Hydrography Dataset (NHD) as the underlying stream-reach network. Final products for this project will be the completion of NHD catchment delineations for the conterminous United States, which will be part of the NHDPlus project to be completed and made available in 2006.