You can create a new vector map and create a line that link the two
points. However, r.carve will interpolate the elevation between the start
point and the end point.
Laurent,
Have this line in a vector map called 'stream.'
If you culvert invert have a lower elevation, this will not show up. But
considering the amount of simplification you're already applying, it could
be acceptable.
The invert has a slightly higher elevation than the outfall. Both are
lower than the elevation of the road over the culvert.
Rich,
In that case, you will not see the accumulation upstream the culvert
that should normally occur if the pipe is actually higher than the
ground.
Please note that in a future version, Itzï will be able to model
culverts more accurately thanks to a coupled drainage model.
But this might be in a few months.
In that case, you will not see the accumulation upstream the culvert that
should normally occur if the pipe is actually higher than the ground.
Laurent,
Both invert and outfall are above ground level and below the road. If
r.carve used the mean elevation between the two then the 'stream' is higher
than the bottom of the roadside swale. This should accumulate water until
the elevation matches the invert, correct?
Please note that in a future version, Itzï will be able to model culverts
more accurately thanks to a coupled drainage model. But this might be in a
few months.
I'd like to do the best that Itzi can with the current version. I may have
opportunities to do more flat land hydrologic models so the more fluent in
Itzi I am the easier it will be and the less I'll be asking for help.
In that case, you will not see the accumulation upstream the culvert that
should normally occur if the pipe is actually higher than the ground.
Laurent,
Both invert and outfall are above ground level and below the road. If
r.carve used the mean elevation between the two then the 'stream' is higher
than the bottom of the roadside swale. This should accumulate water until
the elevation matches the invert, correct?
Rich,
As far as I understand, r.carve interpolate the elevation using as
starting points the DEM bellow the extremities of the vector lines.
So if the DEM at these points is equal to the invert elevation of your
culvert, you're good.
Laurent
Please note that in a future version, Itzï will be able to model culverts
more accurately thanks to a coupled drainage model. But this might be in a
few months.
I'd like to do the best that Itzi can with the current version. I may have
opportunities to do more flat land hydrologic models so the more fluent in
Itzi I am the easier it will be and the less I'll be asking for help.
