The National Map
Data on America's surface waters are available from the USGS in the National Hydrography Dataset (NHD). The NHD includes data sets covering all streams and lakes at scales of 1:24,000 and 1:100,000. In some areas, the NHD is being supplemented with data larger than 1:24,000-scale. The NHD provides a true network that supports the analysis of any type of movement (navigation, sediment transport, effluent dispersion, for example) by surface waters. Further information and data download available at: http://nhd.usgs.gov/.