Changing values manualy on a DEM
I am currently working with DEM raster data and I would like to manually assign a value of 0 to specific raster cells.
Context:
I am currently developing a workflow for a flood-prone area containing levees/dikes. In order to obtain water flow dynamics that realistically reflect the terrain, the drainage structures crossing the levees need to be represented in the DEM, which is currently not the case. To address this, I am considering manually lowering the elevation values of the corresponding raster cells so that a viable flow path can be created through the levee.
I already tried creating a buffer layer around the drainage crossings, rasterizing it, and subtracting it from the original DEM, but this approach did not work.
I also asked an AI assistant for help, which suggested a solution using the Raster Calculator, but that did not work either because, for some reason, my Raster Calculator does not accept expressions containing 'if'or 'null'.
Any ideas ?