Multiple inflow gauges in a single grid is not yet allowed in mHM
Background
Currently mHM only accepts one inflow gauge per L11 grid.
Issue
If there are more than one inflow gauge per L11 grid, it only takes one of the inflow gauge. This obviously leads to error. Seems we need to add this feature in the add_inflow subroutine ??
Tagging subroutine author @thober here :)