Change of residual current system and water quality in ocean basin due to hypothetical breakwater construction project in strait: a systematic solution

摘要

The water quality of Osaka Bay had been significantly affected by the increase in nutrient loads from coastal cities and by the reclamation in the shallow coastal waters. To facilitate the integrative analysis of project-level environmental impact assessment (EIA) in coastal water of Osaka Bay, a methodology of decision support system was developed. In this study we present a trial of systematic approach for the ecological risk assessment of coastal development construction. In the present study, the hypothetical Akashi Strait breakwater project is evaluated to test the usefulness of the methodologies for impact assessment: various model and data sets is assembled and analysed, to make the environmental impact assessment. In this study, potential risks of coastal construction projects to human health and aquatic life in the Osaka Bay are estimated through analysis of their impact on chemical and ecological indicators. Thereafter, the impact/ risk estimates were calculated with couple models for reference sites. The simulation consists of three stages. The first stage is using hydrodynamic model that describes the water flow, the second is applying the water quality model that describes the chemicals and ecological items in the study area, and the third is a set of ecological impact assessment models to do the EIA.