The Architecture of WATERS

Watershed Assessment, Tracking & Environmental ResultS (WATERS) consists of four major components as shown in the figure above:

1. National Hydrography Dataset (NHD) - The National Hydrography Dataset is a comprehensive set of digital geospatial data that contains information about surfacewater features. The NHD includes an addressing system for linking EPA Water Program data to the underlying NHD surfacewater drainage network in order to facilitate its geographic integration, analysis and display.



2. Reach Address Database (RAD) - The Reach Address Database stores the reach address for each Water Program feature that has been linked to the NHD. These reach addresses record the geographic extent of Water Program features in both tabular and spatial formats. The reach addresses link to a static copy of the NHD obtained from the USGS, which also resides in the RAD.



3. Water Program databases - The EPA Office of Water has numerous programs that collect and store water related information in separate databases. By linking the features stored in these Water Program databases to the NHD, the collective information held within the databases can be shared across programs to better facilitate water quality management.



4. WATERS Tools - Tools and applications that generate and use the reach addresses in the RAD to query, analize and display information across Water Programs. The process of assigning NHD reach addresses to Water Program features is often referred to as reach indexing and the tools that support this assignment as reach indexing tools (RIT).