National Hydrography Dataset Catchment Delineations

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.