DEVELOPMENT OF HYDRODYNAMIC, WATER QUALITY AND EUTROPHICATION MODELS - Integrating GIS, Remote Sensing, and Mathematical Modelling for Surface Water Quality Management - page 148

Table (7-1): Delft3D-WAQ selected model substances groups, parameters and associated processes

Substance Group Selected Model parameters Associated Processes

General Continuity, water temperature,

Salinity

Temperature and heat exchange

Oxygen-BOD BOD, COD, DO Mineralisation BOD and COD,

Sedimentation COD, Sedimentation COD,
reaereation of Oxygen.

Suspended Matter Inorganic matter IM1 (TSM) Sedimentation IM1, Resuspension 1st

inorganic matter

Eutrophication Ammonium (NH4), Nitrate

(NH3), Ortho-Phosphate (PO4)

Nitrification of ammonium,

Denitrification of nitrates

The initial conditions for the model were selected to be zero concentrations for all modeled
parameters except the continuity parameter which checks the mass balance of the model. It was set to
1 g/m 3 , so that the model can run to predict the pollutants concentration in the lake at different selected
monitoring points based on the boundary conditions concentration of the inflow from the two main
drains. The model simulation period was selected as the same period for the hydrodynamic modeling,
namely, from the beginning of January 2006 till the end of July 2006. The time step selected for the
water quality model was set to 1 hour. The process parameters for some selected modelled substances
are set to their default values and they are by default constant in time and space. However, process
parameters can vary in time and/or space. Initially process parameters will have the default value that
is taken from the PLCT. These values may be changed in the Process parameters data group.

Model Boundary Conditions and Observation Locations

The boundary sections for the water quality model are selected to be the same boundary sections for
the hydrodynamic model at the locations of the main drains outlets to the lake, where all discharges
enters the lake. Concentrations for different modeled parameters are defined as time varying boundary
conditions at the two sections for the Edko Drain outlet and Barseek drain outlet. The concentrations
used at the boundaries are time series average monthly concentrations for the modeling period. This
time series is developed by linear interpolation between different time breakpoints. The observation
history points for monitoring model outputs are defined to be the same locations for the field water
quality sampling locations for the evaluation and calibration processes. Figure (7-20) shows the
schematization of the open boundaries and observation points locations.

Figure (7-20): Locations of boundary sections and observation
points for water quality model of lake Edko.