Comparing topography of 2 DEM

[lucasMesalles]

Hello,
I am trying to compare two DEM of the same area before and after a flood, and would like to know if there is a tool that permit to quantify the variations of the two DEM. In particular, I am interested on the topographic (i.e. elevation) variations, as I would like to calculate volumes from it. 
It seems to me that it shouldn't be very difficult as it is only a matter of comparing one by one the elevation of each pixel before and after the flood, but I haven't found the adapted tool.
Thanks in advance for your help,
Lucas

[DanPatterson_Retired]

Did you rule out subtracting one from the other? Look for subtract or minus within the spatial analyst for your version, for example, in V10
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z00000093000000.htm

[RussellBrennan]

You could also take a look at the 'Cut Fill' tool. This tool sounds like it is what you are looking for.

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z000000tz000000.htm
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/How_Cut_Fill_works/009z000000vt000000/

[lucasMesalles]

Thanks for the answers.
The CUt-Fill tool is exactly what I needed as it gives me volumetric approximations, which I don't get with the minus tool (which seems however to yield similar results).
Thanks again,
Lucas