Lower boundary condition as free outflow?

Hi,

I have very limited data for my model, including no data for the lower boundary condition so I want to define it as 'free outflow'. However, I cannot find an option to do this in MIKE 11. As far as I can see the only option in MIKE 11 for boundary conditions which doesn't require additional data is 'closed' which is not applicable here.

Any ideas would be appreciated.

Laura

Hi,

In your case, the best practice, from my point of view, is to follow the next steps:
1. If the very downstream sector is important for your study, extend your model in the downstream part with 2-3 Km (with real data, if you have it, or even with some plausible date). The reason is that the last sector upstream the downstream boundary condition is strongly influenced by this condition.
2. Open the Simulation file (mandatory), open from here the editor of the boundary condition file -> Select the row with downstream boundary condition -> than go to Tools (menu) -> "Auto Calculation of H-Q Table..." -> Choose Manning Formula and fill in the fields Slope and Manning's M values with average values used in the downstream sector.
3. Now, a calculated Q-h relationship for your downstream boundary condition is set up.

Please, see the attachment.

Kind Regards,
Aurelian

Hi Aurelian,

Thank you very much.

Laura