MIKE-SHE and MIKE-HydroRiver model run error: “Unable to write dynamic item” - drive space issues?

Question

I am trying to run a coupled hydrology-hydraulic, MIKE-SHE - MIKE-HydroRiver (MIKE 1D) model (2020 version, DHI). To get the MIKE 1D hydraulic simulation to run without stability issues I had to use a 5-second timestep. The coupled model seemed to run without a problem until it was about 83% through, had simulated about 5 years worth, when it showed an error message in the log and the programme closed itself.

The saved WM log file showed the following:

Error writing item file: C:\Users\User\Desktop\working\UpMols\Result\UpMols_13032019.she - Result Files\UpMols_13032019_ET_AllCells.dfs2 msheDFS Error: Unable to write dynamic item Error writing datatype, subtype, time: 1, 1, 44184.0000000000 Termination... Calling MIKE 1D with stop request after 31811040 time steps ... Ok 11:27:50 : Stopped after 82.8 % of simulation

My hard-drive is almost full after this run, so perhaps it is a drive space issue? If MIKE 1D needs a 5-second timestep, is my only option to find more drive space to get this to run?

Answer 1

From the error message (“Unable to write”) and the fact that the simulation made it so far before this, it is probably a drive space issue. Do you need the output of every 5-second timestep? If not you can reduce what gets saved so your hard-drive doesn’t fill up. In both MIKE-SHE and MIKE-Hydro you can set-up the simulations to save the results at larger timestep intervals than the process calculation timesteps. Timesteps for saving results need to be multiples of the calculation timesteps.

In your MIKE-Hydro set-up (.mhydro file), go to “Results specifications” and under this go to “Standard results”. Here you can change the “Storing Frequency” to hourly, daily, or any interval you want.

In your MIKE-SHE set-up (.she file), under “Storing of results”, you can choose which outputs you want to save and set the timestep for saving. The gridded results files take up a lot of space. I’d suggest not saving these at subdaily timesteps unless you really need that for your application. You’ll likely want the grid items flagged as being necessary for the catchment water balance calculation, but perhaps don’t need all the grids on the list, as the grid files take up a huge amount of storage space.

NB: If you set-up saving “Detailed River Time Series” in MIKE-SHE and give this a larger timestep than the MIKE-Hydro timestep, this won’t change what MIKE-Hydro is saving in the background. This will just save another version of the flow or stage output at the timestep you specified and save it with the MIKE-SHE results. To reduce what MIKE-Hydro saves, you need to change that in MIKE-Hydro as mentioned above.