I recently had an interesting question which led to a discussion on how Civil 3D can be used to indicate areas that will be flooded (or not) based on the water being at a specific elevation. From historical data, it is sometimes more accurate to use satellite data to infer the flood line.

We start by creating a surface that is horizontal (solids or regions may also have been used, but in this example, I use a surface)

First, some lines are used to define a surface. A surface style is then used to display the surface as a solid blue color in the plan view. It is then moved into position.

The existing topography is also shown in a style that shows a solid green color in the plan view.

If the elevation of the flood plain must be adjusted, the elevation of the surface is adjusted.

If you need help to show a flood plain like the one in the video above, please contact micrographics so we may be of further assistance.