Running WRF-HYDRO with channel grid routing option

[Jacob Bensabat]

Hello I am testing WRF-HYDRO in a test basin, where I am using two options for channel routing: Muskingum-Cunge (MC) and dynamic wave (channel grid). 

When running with MC I am getting discharges that are  more or less of the order of magnitude of the expect ones but when I am running with the diffusive wave I get much smaller discharges (there are few parameters to twick in CHANPARM.TBL) 

Has anybody experienced such kind of behavior ?

thanks

jac

 

[zed li]

hi jac 

I encountered a problem similar to yours. Previously, when I ran the model using the Diff.Wave-gridded option, the simulated flow was as expected, around 100 cubic meters per second. However, when I switched to the Musk.-Cunge-reach option, the flow was only about 0.5. This is quite strange. Why does just changing the channel routing option have such a significant impact? I tried adjusting variables like btmwdth, n, and ChSlp in Route_Link.nc, but there was almost no change. How do you adjust the parameters in Route_Link.nc? When I used the Diff.Wave-gridded option, I adjusted the MannN in the CHANPARM.TBL file by multiplying it by a coefficient.

thanks
zed

[Arezoo RafieeiNasab]

Hi Zed, 

Do you have a lake above the point of verification? I am asking since there was a bug with the lake routing in the Musk.-Cunge-reach option in the case where there is no spatial weight file (UDMP_OPT=0) in the previous WRF-Hydro version. This issue is not being fixed in v5.4. So if there is a lake above your point of interest, I would encourage you to try the latest version of the code.  

Jacob,

It seems you have a different problem in your case. Do you also adjust the time step of the routing when you switch from reach based to gridded routing? I am referring to (DTRT_CH). I believe there are some recommendations in the user guide on spatial resolution versus temporal resolution in this case. 

Thanks!

Arezoo

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[Jacob Bensabat]

Hi 

Thanks for your message. the size of the time step is 25 seconds and the size of the high resolution cell is 50 m. So the CFL condition is met for wave speeds of up to 2 m/sec, which is safe. 

best

jac