桃園海岸漂砂帶環境調查與健診評估

The Littoral Drift with Environmental Investigation and Assessment in Taoyuan

10.6562/JEE.2012.28.3

錢樺(Hwa Chien)；溫博文(Po-Wen Wen)；魏世聰(Shi-Tsung Wei)

桃園海岸 ； 雷達監測 ； 灘線變化 ； The coast line of Taoyuan ； Radar survey ； the shoreline variation

工程環境會刊

28期（2012 / 01 / 01）

33 - 47

繁體中文

桃園海岸線長度約為47公里，其中人工海岸線長度約佔一半。本文首先彙整相關文獻所分析衛星及空照影像結果，說明桃園大園觀音至新屋海岸的侵淤背景：此段海岸變遷特性主要受極端事件所主導，然而限制於衛星與空照影像資料之片段與不連續，難以釐清並討論單一事件所造成的影響。為能夠量化探討極端事件對於海岸之影響，本研究建立了一套利用微波雷達監測灘線位置之方法，使能夠密集、連續、自動地於惡劣天候下進行大範圍灘線位置之精確監測。進一步本研究以DGPS-RTK測量結果及可見光影像觀測之灘線，與雷達觀測結果比較，確認雷達監測方法之有效性及精確性。極端事件影像方面，本研究以永安漁港南側海灘為例，透過雷達觀測灘線位置的變化討論沙灘受強烈東北季風事件下突堤效應之影響，本文透過垂直剖面潮間帶地形的變化情況估算潮間帶地形之砂的輸送。針對各時間點之灘線位置進行分析，發現隨著離永安漁港南堤越近，海灘坡度愈趨平緩。在單一東北季風鋒面通過事件中，灘線可於短短4天內向岸移動50公尺。此侵蝕速度相當可觀，但從垂直剖面地形變化來看，灘面被侵蝕的區域多位於在潮間帶靠岸的部分，因此即便灘線位置向岸方向前進許多，但實質砂的侵蝕量並沒有這麼嚴重。此方法透過垂直地形的變化圖可以了解沙量的變化，對人工養灘之工程估算有相當大的幫助。

The coast line of Taoyuan county is about 47 km which has manmade about half. In this study, searching and analyzing satellite and airplane images from references show the background information which the coast line was changed in these years. This line changed by extreme event but satellite and airplane images is limited in time and discontinue. It’s difficult to make sure and discuss the influence of an event. For quantify the influence, a method of survey the shoreline was made by micro radar. It can automatically, continually, and intensively to survey the shoreline in bad climate. And make sure the method is useful and correct by comparing with DGPS-RTK and visible light image. For instance by south shoreline of Yong-An fishing port, the shoreline variation was discussed by an extreme event from radar observation. The groin effect and strong northeast monsoon event causes the shoreline moving. This terrain changed to estimate intertidal terrain of sand transported using the vertical cross section of the intertidal zone. Analysis of shoreline position for each point in time, the increasingly gentle slope, beach nearer from the Yong- An fishing port south seawall. In a northeast monsoon event, the shoreline can be moved to land 50 meters in 4 days. From the vertical cross section of the terrain changes, the area is located in a part of the shore intertidal marsh surface erosion. Therefore, even if the position of the shoreline landward direction forward so fast, but the amount of real sand erosion is not so serious. This method through the change in vertical terrain can understand the changes in the amount of sand, with considerable help of manmade beaches engineering estimates.