[GRASS-user] Ability to model flash floo

[Michael Barton]

Ian,

You might be able to use r.watershed (under raster/hydrologic modeling/watershed analysis) to do this. Input your raster of rainfall accumulation as flow accumulation per cell. Then look at the accumulation output. It should be in the same units as your rainfall inputs and should show you the amount of water that accumulates per cell from rainfall and upslope runoff combined. If you convert this to water depth per cell (it may already come out this way depending on your input), you can see how much flooding there is in each cell.

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

voice: 	480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax:          480-965-7671 (SHESC),  480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu


On Aug 5, 2011, at 9:00 AM, <grass-user-request at lists.osgeo.org> <grass-user-request at lists.osgeo.org> wrote:

> Date: Thu, 04 Aug 2011 20:36:51 +1000
> From: Ian Willis <Ian.Willis at checksum.net.au>
> Subject: [GRASS-user] Ability to model flash flooding
> To: GRASS user list <grass-user at lists.osgeo.org>
> Message-ID: <1312454211.1978.42.camel at thorium>
> Content-Type: text/plain; charset="UTF-8"
> 
> Hi All
> 
> To learn how to use grass I've been trying to solve a real world
> problem. The problem that I chose was the flash flooding which occurred
> in south eastern Queensland. I'd like to see if grass could have
> provided reasonably accurate predictions and see if it could be used as
> a warning system.
> 
> Ideally what I'd like to do is use the archived radar rainfall
> information from http://www.bom.gov.au/products/IDR503.loop.shtml#skip
> which can be found on http://gw.barratt.com.au/radar/IDR503/2011/01/10/
> 
> I am intending extrapolate the rainfall rate using the Z value
> conversions recommended for east coast lows as per
> http://www.catchment.crc.org.au/pdfs/technical200207.pdf
> 
> and then convert the rainfall rate rasters to the resolution of the
> aster dem. 
> 
> I believe that the CASC2D module was used for this process as aluded to
> in
> http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.20.318&rep=rep1&type=pdf however it doesn't appear to be available in the current version of grass.
> I was contemplating seeing if I could make it work however before
> muddling along any further I thought that I'd ask for a bit advice. To
> say the least I'm learning a lot about using grass but my knowledge is
> still quite basic. 
> My background is on unix/linux systems so I find the environment
> reasonably comfortable. 
> Any thoughts would be appreciated.
> 
> Cheers Ian