圖書典藏及影音數位平台

利嘉溪口海岸因鄰近臺東市區，不論就海岸防護、親水或景觀等需求面而言，皆屬於重要區段。而影響本段海岸地形變遷機制以利嘉溪河川輸砂及波浪營力為主。有鑑於未來海岸防護應善用海岸自然特性，提升海堤防災功能，減少以永久性之結構物進行海岸防護，以達回復自然海岸之目標，掌握利嘉溪河口輸砂供給對鄰近海岸地形影響之範圍，為目前本段海岸防護治理之首要工作，相關成果可做為後續海岸防護設施維護、河口疏浚及養灘量體研定之依據。 本計畫主要為瞭解利嘉溪輸砂對鄰近海岸地形變遷、海岸漂沙趨勢與海岸防護設施成效等，並研提計畫區海岸整體穩定與防護對策、利嘉溪輸砂平衡管理策略、河口疏濬及養灘之具體方案，以期達到利嘉溪河口海岸防護及環境永續經營之目標。

The study area is started from Yongle Regional drainage to Songzijian at the southern tip of the Taitung Taimali Coast. The coastal topography changes in this project area is mainly affected by the estuarine sand transport of Lijia River, Zhiben River and Taimali River, and natural forces (such as wave, current, and tide). In this project, we integrated by topographic survey data and numerical models to figure out the effects of the three rivers sediment supply on the coastal topography changes. According to the results are found out that sediment transport at estuaries is the main source of coastal sediment supply, and the main supply time are occurred during typhoon attacks. The coastlines of the three estuaries, such as Lijia River, Zhiben River and Taimali River, have a slight extension trend toward the sea side. While the farther away from the estuary, the erosion trend becomes more obvious. Based on topographical data, the slope of the estuary (down to 10 m depth) is at 1/10. And the steep slope from deep water to coastline could lead to a situation that during high flow conditions, the sediment transport from rivers is easy to rush out of the critical water depth of sand movement. Therefore, the estuary sand source can provide near-shore volume and accessibility is quite limited. After further review, apart from Taitung Fengyuan coast, the protection ability of coastal defence structures in each segment of research coastal area, are mostly within the standard value of the security. This result can be used as future research of next year, to work as a whole coastal sand transport management and planning of the coastal environment.