This is basically the channel scenario plus a suspended matter
equation. The settling velocity has to be set in bio_sed.inp.
This Rouse scenario may be calculated with Eulerian concentrations
or with Lagrangian particles, depending on the setting
of bio_eulerian in bio.inp.
When using the Lagrangian particle method, it is advisable
to average the concentration over all time steps
which belong to one output time step,
by setting bio_lagrange_mean=.true.
For further information have a look into the GOTM documentation,
in subsection 'Channel flow - Rouse profile' of the GOTM scenarios section.