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

GRASS GRASS user
1

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.

It does not seem that r.lake will do this, or will it?

Any thoughts?

Thank you,
Tom

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2

On Fri, Mar 28, 2014 at 1:03 PM, Thomas Adams <tea3rd@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