Create a drainage analysis surface from USGS data in Civil 3D

Last updated: 2026-02-06

If you have not downloaded data yet, please refer to Download elevation data for drainage/visualization surface

Warning: Importing DEM files directly into Civil 3D is only recommended for the Lidar-Derived Tiled DEM dataset from GeoData@Wisconsin because there is no coordinate system translation needed. InfraWorks should be used for any other data.

Create surface from elevation file(s)

1. Create a new file.
2. Set the coordinate system
   1. Civil 3D button > Drawing Utilities > Drawing Settings > Units and Zones tab
      1. Categories: USA, Wisconsin
      2. Available Coordinate Systems: Wisconsin County Systems: XX County, US Foot
      3. OK
3. Create a surface
   1. Toolspace > Prospector > Right-click Surfaces > Create Surface...
      1. Surface layer: E_SURF_*
      2. Name: appropriate surface name
      3. OK
4. Set Data Clip
   1. View the Topo mapping with WisDOT Imagery tab Imagery dropdown > USGS Topo
   2. Draw a closed polyline around the area where the surface is needed. Make this area as small as possible to improve system performance.
   3. Toolspace > Prospector > Surfaces > Surface Name > Definition > Right-click Boundaries > Add...
      1. Add Boundaries
         1. Name: Data Clip
         2. Type: Data Clip
         3. OK
      2. Click the closed polyline
5. Add DEM file(s) to surface definition. For each GeoTIF file:
   1. Toolspace > Prosector > Surfaces > Surface Name > Definition > Right-click DEM Files > Add...
      1. Navigate to GeoTIF file
      2. OK
6. Save the file