I have a high water elevation for a location and I want to subtract this elevation by the DEM raster to achieve a water depth raster, and I am not sure how to go about this.

I am assuming a constant water elevation across this location and want to create a rough flood inundation map with the water depths at each point.


I just needed the raster calculator. Here is what I put in the equation:

HWE - "DEM@1"


  • HWE = value of high water elevation at same vertical datum and units as DEM raster (e.g. 44)
  • DEM = the file name of the DEM layer which I used
  • 1
    Well done. Feel free to mark your answer as the solution. – RyanKDalton Dec 3 '19 at 20:55

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