[GRASS-user] Calculate flooded area based on precipitation

[Rich Shepard]

On Thu, 16 Feb 2017, Laurent C. wrote:

> Culverts usually don't appear on a raster DEM. For instance, if you use
> LiDAR DEM, you will have only the elevation of the road surface.

Laurent,

   The culvert is below the road surface and about 60cm above the bottom of
the roadside swale.

> To model a functioning culvert, you will need to lower locally the DEM to
> let the flow pass. Therefore, I'm not totally sure to understand how you
> modelled the functioning culvert without changing the DEM.

   I'm re-running the analyses taking a slightly different approach and will
carefully modify the DEM so the cells with the culvert (in- and outflow)
have the appropriate elevations.

   If I correctly recall reading the Itzi technical information I can
generate time series. I'll re-read everything and figure out how to model
the flows given daily precipitation rates (mm/hr for each day) over a three
week period, with saturated soils from antecedent precipitation.

Thanks,

Rich