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
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?
General hint:
Please note that r.sim.water has been recently modified in GRASS 6.3-CVS
to support more intuitive units. In case that you use 6.3-CVS, please
check if this (still) matches your input parameters. The manual has
been updated.
The demo script in the source code directory has been updated
accordingly. Get also from here:
http://freegis.org/cgi-bin/viewcvs.cgi/grass6/raster/simwe/r.sim.water/spearfish.sh?rev=HEAD&content-type=text/vnd.viewcvs-markup
Markus
thanks for the information. I look forward to 6.3.
If using GRASS 6.2, would the input units for rain and infiltration be mm/hr ? Or is everything based on meters in 6.2?
thanks.
On 5/14/07, Markus Neteler <neteler@itc.it> wrote:
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?General hint:
Please note that r.sim.water has been recently modified in GRASS 6.3-CVS
to support more intuitive units. In case that you use 6.3-CVS, please
check if this (still) matches your input parameters. The manual has
been updated.The demo script in the source code directory has been updated
accordingly. Get also from here:
http://freegis.org/cgi-bin/viewcvs.cgi/grass6/raster/simwe/r.sim.water/spearfish.sh?rev=HEAD&content-type=text/vnd.viewcvs-markupMarkus
grassuser mailing list
grassuser@grass.itc.it
http://grass.itc.it/mailman/listinfo/grassuser
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
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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.
Mark
On 5/14/07, Huidae Cho <grass4u@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@grass.itc.it
http://grass.itc.it/mailman/listinfo/grassuser
On Mon, May 14, 2007 at 01:32:07PM -0500, M S wrote:
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.
Mark
Good - please keep us posted! And don't hesitate to hack the
HTML documentation directly if things should be clarified -
we can then merge it.
Markus