Taiwan Environmental Protection Administration has launched the project entitled “Monitoring Coastal Water Quality at Industrial Sites and Underlying Three Dimensional Hydrodynamic Model around Taiwan” to preserve the precious marine resources and ecological system in the coastal region around Taiwan. The scope of the project has three components: 1. Surveying the water quality at two ocean outfalls from industrial parks and evaluating the impact of the effluents on the receiving coastal waters. 2. Monitoring the pattern of thermal plume from Milliao power plant and investigating ocean current at Milliao harbor and offshore of Hsingda. 3. Underlying a three dimensional hydrodynamic model around Taiwan. Field survey of water quality has been performed in summer, April to May, and in autumn, September to October, for both Tsoying outfall and Dalinpu outfall respectively. The field results showed that the effluents from both Tsoying and Dalinpu outfalls dispersed quite efficiently, the effluent can only be detected within few tens of meter in downstream of the flow direction and few meters above the discharged location. For the behaviors of the thermal plume from Milliao power plant, the thermal plume extends to the southwest during ebb tide and slightly to the northeast during flood tide because of the topographic effects. The temperature rise in the surface layer extends much larger area than the bottom layer due to the positive buoyancy effect from the thermal plume. Ocean current data present a parallel to the shoreline flow direction for both Milliao harbor and Hsingda. In Milliao, water flows into the harbor during flood tide and flows out of the harbor during ebb tide with residual current direction outward. In Hsingda, water flows northwestward during flood and flows southeastward during ebb tide with residual current direction southeastward. POM (Princeton Ocean Model), beating ADCIRC, TSNOW and The Three Dimensional Model of the China Seas, is selected for underlying the three dimensional hydrodynamic model around Taiwan. The model covers 4° x 5° with resolution of one minute. It adopts sigma-coordinate in vertical direction with ten layers. Two finer grid systems within the model domain, 200 m resolution, covering Milliao harbor and Hsingda have been set up simultaneously. So far, model stability test has been completed. Water depth, wind field, and tidal forcing at open boundary have been collected and tested. Preliminary simulations on wind induced current/water level, thermal diffusion of a point effluent source, tide driven current/water level have been tested with promising results for the future works on development of an operational hydrodynamic model around Taiwan.

Costal Water Quality Monitoring, Thermal Plume, Three Dimensional Hydrodynamic Model