環境變遷對臺灣西海岸口湖鄉附近社區衝擊暨永續發展策略-雲林縣海岸開發行為對周邊海岸地形變遷與牡蠣養殖之影響評估(子計畫一)

San-Tiau-Luen sandbars will reach the end of their evolution in the next few years, and in their final stage of evolution, they will play an important role in the coastal disasters and economic activities of the Yunlin coast. The lagoon formed by the sandbar around the west coast of Taiwan is an important sea area for oyster farming and the most important economic activity in the San-Tiau-Luen Coastal Zone. The rapid decline in oyster production in recent years may be related to the shrinking size of the lagoon, which has reduced the area available for oyster farming; the shallow water depth may also change the sediment exchange characteristics of the lagoon, thus reducing the opportunity for oyster implantation. The oyster racks will greatly reduce the hydrodynamics of the lagoon and accelerate the deposition of suspended solids. Oyster farms and harbors have faced geomorphic changes in the past few years, affecting the planning and economic production of a significant number of local fish farmers. In the face of this trend, the potential stakeholders include not only oyster farmers, but also coastal residents, coastal authorities, and coastal developers, etc. Therefore, this study is intended to understand the potential impacts of oyster farming in the Yunlin Sea.In this study, we conducted advanced monitoring surveys and numerical simulations on San-Tiau-Luen sandbars to identify the role of climate change, extreme events, and human-induced development in coastal change, and to understand the current conditions of the sandbars to predict the future rate of change and impacts. This study is divided into two parts, one is "Mobile shore-based microwave radar for intertidal topography and shoreline measurement", using X-band microwave radar to observe the coast, the observation data are continuous strip scan echo intensity images, according to the different echo characteristics of the microwave radar to the sea and land, the original images are produced into radar standard deviation images to distinguish the sea and land, which can be used for long-term monitoring of coastal topography. It is expected to investigate the change of San-Tiau-Luen sandbars under the influence of climate change and extreme events, especially under the pulse impact of typhoon. The second part is "Comparison and Analysis of Simulation Results and Actual Evolution of Numerical Models", in which each commercial model will be used to re-evaluate other cases in the past, to compare the differences between simulation results and actual situations, to discuss how well each model fits the actual evolution of the event situation, and to analyze and compare the differences and strengths and weaknesses between the models. Finally, a numerical test will be conducted to determine the extent and impact of the event on the sea area based on the characteristics of Yunlin sea area and the degree of applicability of each model for reference in coastal management strategy.