Any future changes made to NHD reaches will be recorded in the Info table called RCL within each NHD workspace. These RF3 reaches can be traced through the cross reference table in a fairly straight forward manner. In a small number of cases, RF3 reaches were not translated into NHD reaches. There are 2,120 CUs identified for the conterminous US and Hawaii. This data will be available as high-resolution NHD data.
Data are available for free download in both formats.
Yes, but data on these media must be purchased. Contact any Earth Science Information Center or order online .