Forecasting The Trophic Status Of ToloHarbour, Hong Kong

It is feasible to develop, verify and calibrate a two-layer tidally averaged model which can represent the stratification in the vertical water column during the summer season and can provide reliable estimation of the pollutant concentration in the Tolo Harbour. Eleven systems of water quality parameters are modelled, including three organic parameters, six inorganic systems and two biological parameters. The mathematical model can predict the tidally-averaged results in each layer during the summer season when the coastal waters are stratified. In addition, extensive field and laboratory experiments are required to be carried out in order to determine suitable values for the relevant model parameters. These include the phytoplankton growth kinetics due to temperature, solar radiation and nutrient effects; phytoplankton death kinetics due to endogenous respiration and zooplankton grazing; sediment interactions and eutrophication; phytoplankton settling rate; phytoplankton and dissolved oxygen relationship. Some of the rate coefficients can then be obtained by tuning the parameters with the field data. A sensitivity analysis is then entailed to investigate the relative importance of the pollutant sources and other model parameters on the water quality of the coastal waters. The model can finally be used to forecast the trophic status of the Tolo Harbour, a valuable practical application.