Simple flood / innundation surface

Discussion created by dmede on Nov 30, 2012
I need a workflow for a simple flood surface or inundation area based on a river network. My inputs are just a 10m DEM and river vector file. How do I create or find the portion of the DEM that would be under water for a 3m river flood?

Keep in mind that I don't want a single contour for the entire DEM that represents a flood area, since my rivers as the source of the flood change in elevation through the DEM, I need the area of the DEM is 3m above the local portion of the river.

All the help I can find online wants to treat the flood source as having a single elevation (like a lake or shore line) that floods the DEM to a certain single depth contour. I need something that adjusts to the elevation changes in the flood source.