氣候變遷導致極端降雨與乾旱現象加劇，台灣南部水資源壓力持續上升，因此政府積極推動海水淡化作為備援水源，然海水淡化伴隨的高鹽度鹵水排放已成為潛在環境風險，尤其當排放區位處港灣等水體交換能力受限之半封閉環境時，其對水質與生態可能產生長期影響。本研究擬深入探討港灣及鄰近區域鹵水排放後之擴散與混合行為。
本研究以具有雙開口構造與複雜流場的高雄港作為案例，建立 Delft3D 三維數值模式進行高濃度鹽水排放模擬，評估鹵水於港內不同動力條件下的傳輸行為。研究重點包括：近岸鹽水的傳播方向與擴散距離、底層和表層混合與分層機制、以及港內各區域潮汐交換效率。比較港口間交換效率可知，第一港口因其幾何束縮與較高流速，具有較強的潮汐驅動能力，有效促進鹽水與污染物排出。本研究發現潮汐為鹽水在沿岸及向離岸方向傳輸的的主要機制，而波浪會造成傳輸方向的轉變。本研究期望藉由模擬結果了解港區鹵水動力機制，並為海淡廠排放規劃提供技術依據與環境管理參考，促進水資源發展與生態保育之平衡。

This study investigates the seawater exchange capacity in Kaohsiung Harbor by simulating brine discharge within the harbor basin and analyzing the transport of high-salinity water after it exits the port. The analysis focuses on both alongshore and offshore directions. Kaohsiung Harbor is a unique dual-inlet harbor, which distinguishes it from most other harbors worldwide. The simulation results indicate that tidal dynamics are the dominant driver of water exchange. Specifically, the alongshore and offshore transport distances are primarily controlled by the tidal cycle—spring tides and neap tides influence different spatial directions. In addition, during July 2019, when wave activity was more significant, strong wave-induced alongshore currents were observed. These currents substantially enhanced the northward transport of brine along the coast.

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