圖書典藏及影音數位平台

慈堤～水頭商港北堤以北海岸位於大金門西側，因颱風或季風波浪侵襲，造成沿岸地形改變，經金門縣政府與當地居民反映，現況灘面較以往呈現侵蝕狀況。由於此區域過去較少進行水深地形及波浪調查，因此有必要針對海象、地形水深、波浪及底質等進行調查，以供未來擬定海岸防護對策參考之依據。

This project is divided into two years; this year is the first year. The investigated scope is from Chee-Tsutsumi south to Wujiang river estuary north. Work Including: (1) basic data collection analysis, (2) topography survey and analysis, (3) the tidal-wave-current analysis, (4) the seabed sediment characteristics analysis, (5) coastal protection methods.Two-dimensional Coastal Evolution Models analysis, in winter, wave height mostly less than 0.1 m; Mostly current speed is lower than 0.01 m/s, coast topographic rendering roughly stable. By the summer, topographic rendering roughly stable, near the offshore sandbar present slightly erosion sedimentation phenomenon between Chee-Tsutsumi and Husia. For 50-years-return typhoon, the wave height between 0.3 ~ 0.8 m, mostly only Wujiang river due to masking effect, the nearshore wave height between 0.1 ~ 0.3 m; on a larger speed about 0.06 ~ 0.18 m/s, cause by the circulation between Chee-Tsutsumi and Husia , others is lower than 0.06 m/s. After 50-years-return typhoon, topography appeared to erosion sedimentation phenomenon exchanged now, t erosion than sedimentation and Husia erosion is serious. Between Sia-Bu-Sia and Wujiang river is the sedimentation than erosion.For 50-years-return typhoon, both coastal areas pass through a set-up safety assessment. Because of this meteorological and oceanographic condition is mild in this area, won’t produce serious erosion. This study suggests that temporarily maintaining the original, or can be used to geotextile protect the coast.

本研究為金門海岸基本資料監測調查的第一年，範圍涵蓋慈堤以南至浯江溪口以北海岸。工作項目包括基本資料蒐集、海岸水深地形測量與變化分析、潮波流調查、底質漂砂特性分析，以及研擬海岸防護對策。 研究顯示，金門沿海潮汐為半日潮型，潮差可達 6.81m。海流漲退潮時流向主要為東北及西南方向，流速可達 169 cm/sec。夏季波浪主要來自東南向，冬季則以東向為主，並曾觀測到 9.12m 的颱風巨浪。 近岸地形平緩，多為泥沙灘地，寬度介於 20-185m。金烈航道海底多礁岩。近年來，水深 -10m 以深海域呈現侵淤互現，而近岸地形變化不大。衛星影像分析顯示，海岸線有微幅後退趨勢，近八年平均後退約 16.83m。 底質以粉砂為主，漂砂方向大致平行海岸線。數值模擬結果顯示，在目前波浪條件下，海岸已達平衡狀態，未來變化不大。然而，在 50 年重現期颱風波浪作用下，部分區域可能出現侵蝕。 初步判斷海岸侵蝕原因與人為因素（如海砂開採）有關。短期建議採取「零方案」，維持自然狀態；若持續侵蝕，則建議採用地工砂管保護方案。