A feasibility study of seawater improvement projects in selected bays where seawater is highly polluted by organic substances is being conducted. The study includes field surveys in these bays of, for example, seawater quality, sediment characteristics, sediment release rate, sediment settling rate, organism growth rates, and biological activity. Numerical analysis of the situation is also being conducted, using a set of mathematical models. A water quality prediction model was formulated on the basis of phosphorus cycling between seawater, phytoplankton, and sediment. The results of the simulation predicted that the effect of seawater quality improvement would be unexpectedly small, because of dilution due to advection and dispersion by seawater circulation. However, in the field, ecological conditions seem to be significantly improved, given that the number of benthic species and the populations of these species increase on treated sediment, even though the improvement of water quality is less than expected. Based on these results, the author discusses the role of the numerical model and gives examples of its application in predicting the environmental improvement due to seawater quality improvement.
Water Quality Prediction at Mandae Watershed using SWAT and Water Quality Improvement with Vegetated Filter Strip
