平面漂沙模式在和美漁港之應用

Abstract

臺北縣和美漁港位於臺灣東北角與三貂角北側之小灣內，興建後於民國七十九年 發現港內因大量漂沙流入而淤塞。本文以平面漂沙模式探討建港前後波場與近岸流流場之分 佈特性，並分析建港後海域地形變化情形。本文同時進行水工模型試驗，由試驗結果校核數 值模式之波高與近岸流流場分佈，結果顯示兩者呈現合理之一致性。由波、流場之分析結果 顯示，本海岸流場以中段淺礁區為界分成兩個環流流場，而漁港淤塞之流場主要為東南或東 南東向入射之波浪所造成。東北或北北東向入射波浪受北防波堤遮蔽影響，未能將淤滯港內 之漂沙帶返南測海岸，導致漁港南測金沙灣漂沙之回淤減少而造成海灘之侵蝕。 Homei fishing port is located at the northeast coast of Taiwan. It was full of sediments, and the southern Jinshawan beach was eroded after completion of the port construction. A planar sediment transport model is applied to study changes of waves, nearshore currents, and beach evolution of Homei fishing port. Hydraulic model tessts including wave and flow pattern measurements are performed in order to verify the validity of the planar sediment transport model. Reasonable agreements between the prediction and the experiment are found. Results show that two nearshore circulations induced by ESE or ES swells at the site of fishing port and around Jinshawan are main causes of the port siltation. Predominate waves incident from NNE to NE cannot transport sediments deposited in the fishing port back to the southern coast. As a result, the beach erosion at Jinshawan becomes significant.