Flow path and catchment delineation with buildings

[Ravn]

Hello,
I have some high quality DEM raster files from an urban area. I was thinking to delineate sub-catchment boundaries and flow paths with Arc Hydro Tools, but does anyone have experience how buildings affect to these processes? Buildings have an effect to the flow paths.. Is it possible to take this into consideration?

I could make buildings "hydrologically correct" into the DEM by adjusting building elevations so that water would flow down to ground surface, but is this enough?

Or should I just make the flow path analysis and catchment delineation without buildings and make manual corrections caused by buildings? (this would be too hard for large areas..)

Thanks,

Johann.

 

[elev8848]

Hi johann:
We are in a similar situation and currently trying figure out how to approach this. I think hydrologically, it is a correct approach.

So the only issue is doing the raster part correctly.
My approach will be:
-Assign the building with NoData-or some high value.
-Just for the catchment delineation process, it is not necessary to account for the flow generatated on building roof.

Also, watersheddelineation geoprocessing model is a quick workaround (instead of Arc Hydro) available in ESRI:

http://arcscripts.esri.com/details.asp?dbid=15148

Another think I want to do is extract catchment parameter like slope from the dem or raster file.

more later