[GRASS-user] r.sim.water - error

M S mseibel at gmail.com
Mon May 14 14:32:07 EDT 2007

The 6.3 manual is much more clear about this than the 6.2 manual.  The infil
map is the rate at which the ground absorbs water once the soil is saturated
(surface water already flowing), not when it is dry.   Also the mm/hr units
was a big help.  the 6.3 manual says that x,y,z can be in feet, as well as
the dx,dy (ft/ft), but the rain and infil in mm/hr.

Thanks!  Looks like I might have some results by tomorrow.


On 5/14/07, Huidae Cho <grass4u at gmail.com> wrote:
> r.sim.water checks if the "maximum" infiltration rate is greater than
> the "maximum" rainfall excess rate and, if so, gives the warning
> "Infiltration exceeds the rainfall rate 'everywhere'!", which is not
> true.
> The r.sim.water manual says:
>   user can provide a runoff infiltration rate map infil in [mm/hr] that
>   control the rate of infiltration for **the already flowing water**,
>   effectively reducing the flow depth and discharge.
> It seems to me that the infiltration rates implicitly given by the rain
> map (rainfall-infiltration) and by the infil map are different.  If they
> are the same, your "rainfall rate = infiltration + runoff" holds true.
> As I understand it, however, infil is not the same as infiltration in
> this equation.
> Huidae Cho
> On Mon, May 14, 2007 at 10:21:12AM -0500, M S wrote:
> >
> >    When I run r.sim.water, I get the following output
> "GRASS_INFO_WARNING(18240,1): Infiltration exceeds the rainfall rate
> everywhere!  No overland flow."
> >    If I understand all the inputs correctly, one inputs the rainfall
> excess (runoff) and the rainfall infiltration, and the intensity (rate) is
> calculated by the module by the equation (Rainfall Excess = Rainfall
> Intensity - Infiltration rate).
> >    How can my infiltration exceed the rainfall rate if rainfall rate =
> Infiltration + runoff?
> >    Mark
> > _______________________________________________
> > grassuser mailing list
> > grassuser at grass.itc.it
> > http://grass.itc.it/mailman/listinfo/grassuser
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