圖書典藏及影音數位平台

台南海岸西臨台灣海峽，部份區域有沙灘及離岸沙洲做為屏障，削減入射波浪能量，部份區域則設置海堤減少災害威脅，然近年來，台南海岸部份區段及離岸沙洲呈明顯侵退的情形，侵蝕趨勢造成灘地面積縮小，間接影響波浪能量之自然消能，颱風期間嚴峻海象條件下，沿海防護設施面臨波浪直接侵襲，缺乏天然沙灘為屏障的海堤，儼然成為第一道防線，亦曾造成老舊堤防發生潰堤之事件，海水入侵影響堤後人車通阻，威脅居住安全。雖然目前水利署轄管海堤能有效降低海岸潮浪災害機率，但是受到海岸侵蝕、沿海地層下陷與全球氣候變遷衝擊等因素影響，沿海潮浪災害仍無法完全避免。過去興建海堤方法過於強調防災功能，長久觀察後顯示部分海堤生態環境呈現劣化，並有海岸線退縮情形。民國96年行政院核定「永續海岸整體發展方案」，提出自然海岸線比例不再降低作之海岸永續發展理念，水利署遂逐漸將海岸防護工作提升至海岸環境整體改善，並自民國93年起開始推動「海岸環境營造計畫」，歷經十餘年，海堤防護工作辦理內容已經由防災減災功能，逐漸轉為同時兼顧防災與環境復育功能之環境改善計畫。由於海堤興建已完成階段性任務，針對海岸防護需求，水利署依據行政院民國102年2月核定「永續海岸整體發展方案」(第二期)，以「推動自然海岸線比例不再降低作之海岸永續發展理念」，同時納入「國家氣候變遷調適政策綱領」(行政院於民國101年6月核定)，因應未來氣候變遷衝擊策略上，以保護海岸自然環境，降低受災潛勢，減輕海岸災害損失為調適目標。再者104年2月4日海岸管理法公布實施，預計兩年內配合內政部公告實施包含一、二級海岸防護區的「整體海岸管理計畫」，使海岸防護工作更有法理可依循。104～109年海岸環境營造計畫水利署以「陽光海岸，安全家園」為計畫願景，藉由「因應氣候變遷衝擊，規劃推動海岸防護適應策略」、「加強工法研發，提升海岸防護技術能力」、「善用海岸自然特性，展現特色海岸風華」、「維護海堤安全，確保應有防護功能」與「活化海堤空間利用，改善海岸棲地環境」等五大策略，達成「強化海岸防護能力，降低災害損失」、「加速海岸環境復育，營造優質海岸」與「落實海岸防護工法研發應用，維護海堤設施功能」三大計畫目標。本計畫針對台南海岸進行海岸環境營造規劃及氣候變遷因應措施進行研究，計畫分為兩年進行：104年研究範圍為急水溪口至曾文溪口；105年研究範圍為曾文溪口至二仁溪口。針對台南海岸進行現階段及未來氣候變遷情境下，海岸防護功能檢討與環境特性分析，並於各區選擇一區段需改善海岸，依據其海岸環境特色，研提海堤環境營造規劃，以利適應未來環境狀況，期在海岸防護基本功能下，達成上述三大計畫目標。

This project was conducted in two year. The coast between the mouth of Jishui River and the mouth of Tsenwen River was investigated in the first year (2015); the coast between the mouth of Tsenwen River and the mouth of Erren River was investigated in this year (2016). In this year, this project planned to study shore protection and environment characteristics between the mouths of Tsenwen River and Erren River under current and future climate conditions. Is selected a coastal area between the mouths of Tsenwen River and Erren River as the exhibition area of our coastal environment improvement plan. This plan should accomplish shore protection as well as the project objectives of “strengthen shore protection, lower disaster loss”, “accelerate coastal environment regeneration, create high quality coastal environment” and “develop and apply of shore protection engineering methods, preserve seawall function”.In this year, the project organized and analyzed past information about tide level, hydrology, land subsidence, coastal ecosystems, shore protection, disasters over the years. On bathymetric survey and analysis, this project performed control survey in the middle third of May, 2016; the bathymetric survey after winter was conducted between June 1 and June 10, 2016; the bathymetric survey on the coast between Anping Harbor and Erren River mouth after typhoon was conducted on September 19 and Sep. 21~22, 2016; the bathymetric survey on the coast between Tsenwen River mouth and Anping Harbor after summer was conducted in the last third of October, 2016; When we conducted erosion and aggradation analysis, the bathymetric survey results of this project and past bathymetric data were consulted. In addition, the bed load sampling was conducted on July 28, 2016 and then finished bed load sample analysis has been completed.In order to resolve the relation such as coastal environment characteristics and development potential between the mouths of Tsenwen River and Erren River, the coastal land-use distribution, authorities and responsibilities of government institutions, tourist attractions and recreation activities in the investigated ambit were investigated, compatibility with local environment, distribution of coastal creature habitats as well as the sensitivity and development potential of local coastal environment were reviewed. After consulting the review results, the coast section around Kunshen seawall is suggested as the object of our coastal environment improvement plan. The imHarborant issues for improvements of coast section around Kunshen seawall involving the requirement for shore protection, improvement plans of current shore protection, improvement plans of current coastal topology, plans of coastal ecosystem reservation, plans of coastal environment preservation and influences of the improvement plan on neighboring coasts were assessed.For forming and assessing the coastal environment improvement plans of the coast section around Kunshen seawall, the plan functions include disaster and wave protection, coastal landscape, environmental resource, ecosystem, industry development and tourist recreation are suggest. The performances of our improvement strategies and plans are carried out and then proposed the better feasible plans. Furthermore, predicted costs and benefits of the plans are evaluated as well as cooperative measures for applying the plans.In order to form an assessment standard to the weather change response capacity of shore protection improvements, the results of “A study of adaptation capacity of coastal disasters due to climate change in order to strengthen southwest area of Taiwan (1/2)”, and previous climate change research literatures are refered. Also, the design requirements of improvement plans were derived. At the same time, further water rising caused by climate change are investigated, consulted latest bathymetry to calculate wave fields and used estimation models of wave run-up and overtopping for forming an assessment standard to the weather change response capacity of shore protection improvements, strategies and non-structural measures.