DEVELOPMENT OF HYDRODYNAMIC, WATER QUALITY AND EUTROPHICATION MODELS - Integrating GIS, Remote Sensing, and Mathematical Modelling for Surface Water Quality Management - page 157

Table (7-5): Statistical evaluation of sensitivity analysis
The overall statistical analysis indicates that the decay rate of BOD is the most sensitive parameter to
the modelled DO concentration. The relation is an inverse relation, i.e. increasing the decay rate
parameter decreases the DO concentration. The temperature coefficient is also of significantly
sensitive in the model. It should be highlighted here that the calibration of the TSM (and CHL-a) was
done in this research study based on the application of remote sensing techniques and methodologies
as presented in chapter8 . An important objective in this research was to test and prove the capabilities
of remote sensing in filling the gaps in data scarce environments, and overcoming the complexity of
the calibration of both modelled parameters when there are practical limitations of data availability.
Chapter 8 will involve the detailed calibration procedures of TSM as one of the parameters of both the
basic model and the eutrophication screening model.
7.5.2. Eutrophication Screening Model of the Shallow Lake System
A good and reliable understanding of the lake ecosystem is essential for economical and ecologically
feasible and sustainable lake management. Most managers are very interested in models which can be
powerful tools to simulate the changed water quality of lakes due to eutrophication and to test various
management options to restore the lake conditions. Ever since it emerged in the early 1970s,
eutrophication modeling has been considered a step forward from the hydrodynamic models because it
incorporates chemical and biological processes as well as environmental management aspects into the
transport processes. Since then numerous eutrophication models have been developed to simulate
different ecological and hydrodynamic processes with a wide range of different complexity in both
processes. The eutrophication model is considered a complex model with respect to its structure and
its data requirements, as it includes both chemical and biological sub-processes which interact in
several meta processes and these processes are linked directly with the hydrodynamic results.
For the case of Lake Edko as an example of a shallow lake system under eutrophic stressing
conditions, a simple eutrophication screening model is developed as an initial step for managing the
lake system. The detailed processes of eutrophication were not all included because the scope of this
study is not the ecological modeling of lakes but to make use of the hydrodynamic model and couple it
with the eutrophication model for a better understanding of the conditions of the lake.
The eutrophication model developed for the Lake includes the following parameters of interest: total
suspended matter (TSM), nutrients group including ammonia (NH4) and Nitrates (NO3) and CHL-a.
These parameters were selected as the main indicators for the eutrophication condition of the lake.