Hydro1k North American - Flow Direction

HYDRO1k is a geographic database developed to provide
comprehensive and consistent global coverage of topographically
derived data sets, including streams, drainage basins and
ancillary layers derived from the USGS' 30 arc-second digital
elevation model of the world (GTOPO30). HYDRO1k provides a suite
of geo-referenced data sets, both raster and vector, which will
be of value for all users who need to organize, evaluate, or
process hydrologic information on a continental scale.
Developed at the U.S. Geological Survey's EROS Data Center , the
HYDRO1k project's goal is to provide to users, on a continent by
continent basis, hydrologically correct DEMs along with
ancillary data sets for use in continental and regional scale
modeling and analyses.