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<font size="+1"><font face="serif">Hi Users on the list<br>
<br>
To trace back the overland flood mechanism in (sub)urban area I've done
some experiments in grass.<br>
(Sub)urban areas has in general a sewer-system (combined or storm).<br>
One of the design-parameters of a sewer is the maximal capacity of
rainfall, in most cases e sewer is design<br>
to carry off about 20mm/h rain.<br>
<br>
In case of very heavy storm about 60 mm/h the sewer becoms full and an
overland flood mechanism come into being.<br>
<br>
I've a 5x5 meter grid DEM of the area.<br>
In grass there are several modules to simulate overland flood.<br>
<br>
* r. terraflow<br>
* r.watershed<br>
* r.topmodel<br>
* r.topidx<br>
...<br>
<br>
What is the most useful module(s) in grass to simulate overland flood
mechanism?<br>
<br>
<br>
First I used the r.terraflow module the resulting accumulation map is
here:<br>
<a href="ftp://192.168.2.107/houtblerick/teracc.png">Terraflow
accumulation map</a><br>
<br>
Using the r.watershed module resulting streammap is here:<br>
<a href="ftp://192.168.2.107/houtblerick/wsstream.png">Watershed stream
map</a><br>
<br>
In both maps the red boxes are the complaints of water flood<br>
A foto of the real situation is here<br>
<a href="ftp://192.168.2.107/houtblericj/Holleweg.jpg">Foto</a><br>
<br>
Thanks<br>
<br>
Joop Goedbloed<br>
<br>
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