TOPMODEL in GRASS

[Raymond Venneker]

> 	There has been some discussion on this list before about using
> TOPMODEL in GRASS.  Most of us have just figured that using the r.watershed
> was good for calculating the parameter "a".
> 
> 	However, I have recently learned that it is important that the
> water be allowed to follow MULTIPLE FLOWPATHS for a reasonable accurate
> saturated area map.  Has anyone implemented such a routine in GRASS?
> S. Chairat and J. Delleur have published a paper on this, but I don't know
> how to get their algorithm (S. Chairat is in Tunisia).  I would be very
> interested in discussing this further with anyone.
> 
> Jane Rossing
> jr20 at cornell.edu

Below are some references, see Costa-Cabral & Burges for an extensive
discussion on single/multiple flowpaths. Freeman contains an algorithm
(but note the difference of the power coefficient between Freeman and
Holmgren!). I have some preliminary code but *not* for grass because
there is not floating point raster support yet. You may contact me
directly if you need more info.

Could you provide a pointer to the Chairat/Deleur paper?

-Raymond (venn at geo.vu.nl)

[WRR: Wat. Resour. Res.; CG: Comp. & Geosc.; HP: Hydrol. Proc.]

@Article{b-costacabral-burges-94,
	author = "M. C. Costa-Cabral and S. J. Burges",
	title = "Digital Elevation Model Networks {(DEMON)}: A Model of
	Flow over Hillslopes for Computation of Contributing and
	Dispersal Areas",
	journal = WRR,
	volume = "30",
	number = "6",
	pages = "1681--1692",
	year = "1994",
}

@Article{b-freeman-91,
	author = "T. G. Freeman",
	title = "Calculating Catchment Area with Divergent Flow Based
	on a Regular Grid",
	journal = CG,
	year = "1991",
	volume = "17",
	number = "3",
	pages = "413--422",
}

@Article{b-holmgren-94,
	author = "P. Holmgren",
	title = "Multiple Flow Direction Algorithms for Runoff Modelling
	in Grid Based Elevation Models: An Empirical Evaluation",
	journal = HP,
	volume = "8",
	pages = "327--334",
	year = "1994",
}

@Article{b-quinn-et-al-91,
	author = "P. Quinn and K. Beven and P. Chevallier and O. Planchon",
	title = "The Prediction of Hillslope Flow Paths for Distributed
	Hydrological Modelling Using Digital Terrain Models",
	journal = HP,
	volume = "5",
	pages = "59--79",
	year = "1991",
	note = "Reprinted in Beven and Moore (Eds), 1992",
}