I have a polygon layer that represents the max inundation extent along a stream for the one-year storm event (generated in hec ras).
If this floodplain was theoretically raised by one foot, what would the new floodplain extent look like?
This would be easier to do if the floodplain polygon was one elevation, but it's along a river so the elevation of the floodplain changes throughout the reach. I have ArcGIS Advanced Desktop and Spatial Analyst. I also have a high resolution DEM for the area.
How do I generate a new surface extent for this higher floodplain?