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.

1 Answer 1


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. Dec 3, 2019 at 20:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.