[GRASS-user] Trying to create a water depth map

[Markus Neteler]

On Fri, Mar 28, 2014 at 1:03 PM, Thomas Adams <tea3rd at gmail.com> wrote:
> All;
>
> I'm trying to create a water depth map using the following:
>
> (1) DEM
> (2) vector polygon indicating the lateral extent of inundation
> (3) stream channel centerline
>
> I figure I can intersect the polygon with the DEM raster to get the water
> surface elevations along the boundary of the extent of flooding. Assuming
> that perpendicular to the stream channel centerline, the water surface
> should be level, I don't know how to interpolate water surface elevations
> across the channel. But, if I can do this, I could, using r.mapcalc, do a
> simple subtraction between the water surface elevation raster and the DEM
> raster, resulting with a flow depth raster.
>
> The water surface elevation should, of course, decrease in value in the
> downstream direction.

Please take a look at r.carve:

http://grass.osgeo.org/grass70/manuals/r.carve.html

Markus