圖書典藏及影音數位平台

花蓮海岸位於臺灣東部，每年颱風侵襲頻繁，為保護沿岸國土及百姓生命財產安全，本局除辦理相關海岸防護措施外，並於民國75年起持續迄今辦理南北濱及化仁海岸監測調查計畫，並自91起陸續增加七星潭海岸、94年水璉海岸、95年牛山海岸、96年東興至豐濱海岸、98年環保公園海岸、102年崇德與新城海岸、105年鹽寮海岸等，其監測調查主要工作項目為0m灘線至斷面樁後10m之陸域測量、南北濱與化仁海岸(-150m)及餘計畫範圍(-100m)之水深測量、灘線變化分析等，歷年所得資料，除積極整合建置外，亦將上述區域之監測資料分析比對，以作為後續海岸防護對策研擬之參考依據。 然花蓮海岸因受天然地形地勢影響，現場波、潮、流、海氣象、漂沙、輸砂及海床地形等資料蒐集不易，且考量本局於重要海岸如七星潭(北埔安檢所)、北濱(忘憂亭)及南濱(守望哨)等陸續完成即時影像監視站建置，爰嘗試以非接觸式遙測及影像比對等技術，進行表面流場、流速、海浪溯升及灘線變化等分析，進而與傳統觀測或數值模擬結果等進行比對驗證，以期提升海岸觀測技術及掌握海岸現況水文環境；另花蓮海岸溢淹問題常受波浪溯升影響，惟現階段之海岸波浪溯升計算方式如推估方法及受地形或結構物影響之削減係數等仍待分析及驗證，故本案除現場波流場之觀測與資料蒐集外，亦期建立與修訂花蓮海岸(陡坡、礫石、灘崖與不同形式防護措施)之波浪溯升推估模式，俾提高波浪溯升預測之準確度。

Due to the impacts of climate change, the challenge of coastal protect will be more and more serious. Coastal bathymetry and current are two keys to evaluate the effects of coastal protect. Although the in-situ measurement must be the most reliable way to obtain the coastal bathymetry and current data, the risk and cost of this way should be considerable as well. Marine X-band radar, which is typically used to detect the coastline and obstacles on the sea surface, is currently one of the most widely used tools for the remote sensing of coastal area. In addition to the coastal protection, wave run-up on the sea dike is one of the risks of coastal flooding. The aim of this work is to monitor the coastal bathymetry and current using remote-sensing technologies. In addition, the wave run-ups monitoring and prediction are also carried out in this work. The results of this work are summarized here: 1. Integration of existing data and information: The results show that extreme sea states in Hualien coastal area were observed from July to October due to the impacts of typhoons. Besides, the winter monsoon is also a main factor to induce higher wave heights. 2. Evaluations of stations for coastal monitoring: The Hua-ren coast is suitable for the stations of radar and wave run-up. 3. Stations establishment and video data acquisition: To obtain coastal environmental information, we establish one radar station and one wave run-up monitoring station. Real time videos from three different coastal areas are acquired for detecting the shore line. 4. Data analysis and strategies development: Radar images are collected continuously. After the comparisons between radar and in-situ data, we confirm the root mean square error of current results is 0.08 m/sec and the error of bathymetry is 0.7 m. The seasonal variations of current data are also discussed. The components of tidal current are less than 0.1 m/sec. Based on the results of data analysis, we evaluate the coastal area with high risk. We also propose different strategies for the future works of coastal protection. 5. Establishment of wave run-up prediction system and its calibration: The run-up elevation on the sea dike is predicted based on the ensemble forecast. The results of prediction are calibrated based on the in-situ data of wave run-up during typhoons this year. 6. Other works: In addition to the radar measurement at Hua-ren coast, the mobile radar monitoring missions are also carried out at different coastal areas of Hualien County.