[GRASS-user] Re: Hydroligics in grass

GRASS GRASS user
1

I start with, which method is better depends in part on your needs and your data.

That said, we've done a lot of testing in my lab of the ability of these (and other modules like r.flow) to simulate overland flow. We've had the best results with r.watershed with the new multi-flow direction (MFD) algorithm implemented in GRASS 6.5 and 7.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 12, 2009, at 4:13 AM, grass-user-request@lists.osgeo.org wrote:

Date: Fri, 11 Dec 2009 21:05:58 +0100
From: Joop Goedbloed <jlgoedbloed@hetnet.nl>
Subject: [GRASS-user] Re: Hydroligics in grass
Cc: grass-user@lists.osgeo.org
Message-ID: <4B22A626.4000304@hetnet.nl>
Content-Type: text/plain; charset="iso-8859-1"

Op 11-12-09 20:44, Joop Goedbloed schreef:

Hi Users on the list

To trace back the overland flood mechanism in (sub)urban area I've
done some experiments in grass.
(Sub)urban areas has in general a sewer-system (combined or storm).
One of the design-parameters of a sewer is the maximal capacity of
rainfall, in most cases e sewer is design
to carry off about 20mm/h rain.

In case of very heavy storm about 60 mm/h the sewer becoms full and an
overland flood mechanism come into being.

I've a 5x5 meter grid DEM of the area.
In grass there are several modules to simulate overland flood.

* r. terraflow
* r.watershed
* r.topmodel
* r.topidx
...

What is the most useful module(s) in grass to simulate overland flood
mechanism?

First I used the r.terraflow module the resulting accumulation map is
here:
Terraflow accumulation map <ftp://192.168.2.107/houtblerick/teracc.png&gt;

Using the r.watershed module resulting streammap is here:
Watershed stream map <ftp://192.168.2.107/houtblerick/wsstream.png&gt;

In both maps the red boxes are the complaints of water flood
A foto of the real situation is here
Foto <ftp://192.168.2.107/houtblericj/Holleweg.jpg&gt;

For the puctures try ftp://80.61.251.86/Houtblerick/
there are the tree pictures.

Thanks

Joop Goedbloed

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On Sat, 12 Dec 2009, Michael Barton wrote:

That said, we've done a lot of testing in my lab of the ability of these
(and other modules like r.flow) to simulate overland flow. We've had the
best results with r.watershed with the new multi-flow direction (MFD)
algorithm implemented in GRASS 6.5 and 7.

Michael,

   I saw a reference to jgrass in an earlier thread. I've not yet looked
closely at it but it apparently has modules lacking in GRASS for
precipitation-runoff calculations. Have you or your students looked at
jgrass?

   Ideally, it would be nice to have all the additional capabilities of jgrass
incorporated into (C)GRASS.

Rich