Complexity modes in GREAT-ER

Frank Koormann frank.koormann at
Wed Jun 25 16:19:05 CEST 2003

Hello Johan,

* Johan Olanders <pejo20 at> [030625 14:37]:
> Hello!
> Finally I have, since a couple of days with Jan-Oliver's help, got the River
> Ouse, Sussex, UK working and the initial results for the oestrogens I'm
> modelling make sense!

Great :)

> Now I have some questions about complexity modes!
> Is it possible to run GREAT-ER with different complexity modes for Sewer,
> WWTP and River? I had planned to run GREAT-ER with complexity mode 2 for the
> River and keep the Sewer and WWTP in complexity mode 1. (Seems as
> impossible?)

As far as I remember even in GREAT-ER 1.0 the complexity modes for the 
different compartments can be selected seperately. Nevertheless, the 
requirements display is not that simple: Selecting mode 2 for one
compartment enables the mode 2 requirement display for all compartments.
This will be overcome with GREAT-ER II. 

Sufficient should be
Substance - Partitioning: Kd River
          - River Removal:     k (deg)
                               k (sed)
                               k (vol)
> What does the "Impose default complexity mode" option do?

This is something experimental in GREAT-ER 1.0: The experienced user had
the ability to handcraft an exception file to specify complexitly modes
for selected river stretches or discharges. With the "impose" check the
model was forced to use the compartments general complexity mode for
_all_ objects. This has been dropped for GREAT-ER II to make results for
one catchment more transparent and comparable.

> As far as I can see in complexity mode 2 and 3 for the river there is no way
> of taking sorption to bed sediments direct from the water column into
> account. (i.e. the equilibrium water concentration - bed sediments
> concentration.) Is there a work around? Do anyone now if this will be
> possible in GREAT-ER 2?

Since GREAT-ER II reimplements the models of GREAT-ER 1.0 such a feature
is not in there. Also some discussions about extending GREAT-ER II with
a sediment module focussed more on the sediment concentrations, but the
chemicals way to the sediment still via sorption and deposition. The
direct path from the water to the bed has been considered as neglectable
so far.

Kind regards,

        Frank Koormann

Frank Koormann                             <frank.koormann at>
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