Modifications were made to an existing Lake St. Clair topobathy data set 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. A shaded relief map was generated for the modified digital elevation model. 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. The base elevation includes data for Alcona, Alpena, Arenac, Bay, Cheboygan, Chippewa, Huron, Iosco, Mackinac, Presque Isle, Sanilac, St. Clair, and Tuscola counties in Michigan.