Elevation Derivatives for National Applications

Elevation Derivatives for National Applications (EDNA) is a seamless, nationwide, multi-layered three-dimensional (3D) hydrologic database derived from a version of the National Elevation Dataset. EDNA's 3D hydrologic layers are vertically consistent by their very nature, meaning that hydrologic drainage always flows from a higher elevation to a lower elevation and that reach catchment boundaries always follow the elevation drainage divide. This consistency allows for transfer of valuable information from digital elevation models onto EDNA-derived drainage lines and watersheds, including stream gradient, minimum and maximum elevation within a watershed, average watershed slope, and elevation.