A question a flow direction

[jbensabat]

Hello
I am running WRF_HYDRO and for some grids, I get an error due to the fact that some pixels in the grid, where there is a channel, the flow direction is 0. This can happen in real life (points along a stream with a zero slope).
is this a design assumption of WRF-HYDRO ?
best
jac

[scrasmussen]

Hi Jac, modifying my answer as we look into things. Apologies for the delay!

[scrasmussen]

Hi Jac, our code assumes that there are there are no cells with a flow direction of 0. You can see it here in the module_HYDRO_io.F90 code and set HYDRO_D=1 to get an output message. Our preprocessing tools will change grid cells with a flow direction of 0, that might appear if you are using a tool like whitebox.

Quoting one of my co-workers "the pre-processing tools will fill the DEM with a z limit of 1000 to remove pits".

If you have any other questions please let us know!

[jbensabat]

hi thanks for your answer. I understand that now. We have our own data (such as fine topography etc) so we created our own pre-processor for the input files. I have another question that I have posted into the dicsussions part and I would be glad if you could address it: when using the muskingum-cunge model for channel routing, there are two parameters K,X which to the best of my knowledge are determined in real time (Depending on the velocity of the wave). the route_link.nc file requires the values of these two parameters. Does this mean that there are constant in WRF-hydro ? if not what is the reason for providing them ?
best
jac