A study on the environmental impact assessment of the garolim tidal power project

Without a robust guideline for environmental impact observation and prediction, many development projects near coastal and estuarine areas have been conducted. The reason is that each project has its own characteristics, and so it is impossible to apply a single guideline to all of different projects. Thus, the purpose of this study is to present a guideline for the appropriate evaluation of environmental impact from the tidal power project at Garolim Bay. The guideline is focused on three essential subjects (hydrodynamics and water quality, sediment, and estuarine biota) and describes environmental impact observation and prediction for each subject. For hydrodynamics and water quality, the important factors include changes in intertidal area, flow patterns inside the bay area, water exchange time(or residence time), exposed time of intertidal area, salinity and temperature, water quality deterioration (eutrophication and oxygen depletion) etc. For sediment, core issues contain short-and long-term sedimentation inside the bay area, seasonal bathymetry change, sediment transport at the entrance of the bay, sedimentation and suspended sediment outside the bay areas, erosion and deposition rate at the intertidal area, development of the muddy area, distribution of sediment type, and movement of sediment after the project. The range of estuarine biotic communities is very broad including primary producers, benthic communities, shallow water communities, communities at intertidal areas. These estuarine biotic communities are affected by change in flow pattern, intertidal areas, salinity, residence time, turbidity in the water column, exposed time of intertidal areas, sedimentation, and water quality. Therefore, the environmental impact prediction for estuarine biota shall be conducted by considering hydrodynamics, sediment, and water quality, and so that uncertainty is likely to be substantial.