What are the advantages of the NHD?
The National Hydrography Dataset is designed to provide comprehensive coverage of hydrologic data for the US. While based on 1:100,000-scale data, the National Hydrography Dataset is designed to incorporate–and encourage the development of–higher-resolution data required by many users. It will also facilitate the improved integration of hydrologically-related data in support of the application requirements of a growing national user community and will enable shared maintenance and enhancement. Will the NHD replace the existing DLG-3 hydrography data? The National Hydrography Dataset supersedes RF3 and DLG by incorporating them, not by replacing them. Users of RF3 or DLG will find the same data in a new, more flexible format. They will find the National Hydrography Dataset both familiar and greatly expanded and refined. What are ‘RF3’ and ‘DLG’? The U.S. Environmental Protection Agency’s (EPA) Reach Files are a series of national hydrologic databases that uniquely identify and interco
