Modifications were made to existing great lakes topobathy data sets to interpolate areas of missing near shore elevation data. Areas with missing elevation data were not interpolated where there was low confidence in the underlying depth. This included rivers, canals, harbors, lakes, reservoirs, etc. Areas important for targeting Phragmites australis management often lie within these aquatic/terrestrial transition zones. The original topobathy data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the NOAA Lake Level Viewer. It depicts potential lake level rise and fall and its associated impacts on the nation's coastal areas. The base elevation data were the best available lidar and US Army Corps of Engineer dredge survey data known to exist at the time of DEM creation that met project specifications. Shaded relief maps were also generated for the modified digital elevation models.