Is it possible to conduct a flood model analysis with QGIS using a DEM? Need to simulate rising water levels on a 250k map.
3 Answers
If it were me, I'd be looking to
http://www.lutraconsulting.co.uk/resources/crayfish/
and the guys who developed it
http://www.lutraconsulting.co.uk/
This plugin however is only used to view analysis output, and you need input data (in 2dm mesh files and .dat format) from a model (like TUFLOW).
From the crayfish website:
Crayfish Viewer can be used to view results from hydraulic modelling packages and other software that write SMS .2dm mesh files and .dat (binary) data files. These modelling packages include TUFLOW and ISIS 2D.
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to respectfully contrast @underdark's answer and InaSAFE, I suspect you are going to want to produce results related to time and so will need to include Mannings n as a parameter in the model.– WillyCommented Feb 1, 2013 at 7:58
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Depending on your needs, this method might be of use.
I have not tested this in QGIS, but it should be possible.
basically you use cost of distance to set the "cost" (as height) of the water flow. This way you get connected polygons of same hight. Thus this method represent rising water levels well, but not necessarily storm floods and the like.
In QGIS 3.x series, you can use native Mesh Layer that uses MDAL library to read most of the formats used in flood modeling. QGIS Crayfish Plugin can be used to plot the data.