GREAT-ER Class Concept
Frank Koormann
frank.koormann at intevation.de
Mon Aug 23 11:13:26 CEST 2004
Dear all,
as you may have noticed a new CEFIC LRI Project has started to add a
first and rather simple sediment component to GREAT-ER: Simple
equilibrium concentration in sediment as described for the WATER model
(which is implemented by GREAT-ER).
The parameters needed for this approach are already in the GREAT-ER
database, as fields in the stretch class table. Some of these have to be
made editable by the user. I will illustrate our plans from the
parameter editing point of view, describe some consequences to the
class concept and I would like to ask for your comments on this:
The class concept
(implemented by GREAT-ER 2.0 as well as 1.0) allows to define
distinct parameter sets for different types of stretches in a catchment.
However, in personal communication it always has been considered as
somewhat experimental and not of much use since the parameters have to
be defined during catchment preprocessing. They cannot be
changed/displayed later on.
For the sediment module at least the suspended solids concentration
(SS_RIVER) has to be editable by the user, we will add this to the
environmental parameters. As a consequence a single SS_RIVER probability
density function will be applied for the entire catchment. We are
planning to add also the other parameters needed for the equilibrium
calculation to the environmental parameters:
f_oc: Organic carbon fraction of suspended solids in river
rho_sed: Dry sediment density
eps_sed: Volumetric water fraction of the sediment
As for all environmental parameters default values will be defined which
will overwrite the values from river classes. For users who really want to
work with classes will will add a choice to the model mode dialog:
- Use class parameters
- Use environmental parameters
Your thoughts?
Thanks in advance,
Frank
--
Frank Koormann <frank.koormann at intevation.de>
Professional Service around Free Software (http://intevation.net/)
FreeGIS Project (http://freegis.org/)
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