Database

A variety of EPA and State databases have been linked to the NHD using the NHD-RIT and other tools. The EPA and State databases then become part of EPA's Watershed Assessment, Tracking, and Environmental Results (WATERS) database. WATERS integrates the different datasets via the NHD and allows for queries between the programs. For example, you could query the National Assessment Database and the National Listing of Fish and Wildlife Advisories (NLFWA) and find out how many of the waters in the US that are impaired by Mercury also have Fish Consumption Advisories. The following URL will take you to a list of the links for the different programs that are a part of WATERS.
https://www.epa.gov/waters/data/prog.html