氣候變遷衝擊下之區域排水改善與防洪管理

Abstract

近年來全球極端氣候發生的頻率日趨增加，經常造成經濟與社會上重大的損失，尤其在現今人口與經濟快速成長的時代裡，大量的公共建設常開發在原本較易淹水的低窪地區，為了杜絕洪災主要都採取工程方法以減少洪水災害，然而在設計基礎防洪措施時如有地方社區民眾之公眾參與，將可幫助決策者、工程師與當地民眾之間進行交流，以決定正確的防洪減災管理策略。本研究以高雄市土庫排水集水區為例，其低窪地區近年來之土地開發與人類經濟活動頻繁，在颱風暴雨侵襲時，常造成淹水事件，另外本研究建置排水淹水模式，結合區域排水模式與二維漫地流淹水模式，用以評估防洪管理策略與洪水災害損失，其中防洪管理策略經由舉辦地方之公聽會，建立基本防洪管理共識，包括增加排水流量、使用魚塭當作滯洪池、建置抽水站與分洪道。在評估未來氣候變遷衝擊的影響部分，將利用聯合國發表之氣候變遷情境，增加降雨強度以模擬各種情境之淹水範圍與深度，並利用各種情境之災害損失，評估各種防洪管理策略。本研究期能針對排水相對困難的低窪易淹水地區，經由決策者、工程師與地方民眾相互溝通取得基本共識的原則，模擬在氣候變遷衝擊影響的情況下，採用適合的洪水管理方案。

Frequent floods caused by extreme weather conditions have caused considerable economic and social losses in recent years. Currently, numerous infrastructures have been built in the lowland areas that are prone to inundation, where measures and solutions for flood mitigation mainly have engineering aspects. Runoff discharge has increased with land development and human activities in the Tuku lowlands, Taiwan. Public participation in the township helps both stakeholders and engineers determine the principles of flood management for effective communication. An integrated drainage-inundation model combining the drainage flow model with the two-dimensional overland-flow inundation model is used to evaluate the flood management approaches with damage losses estimation. The proposed approaches include increasing drainage capacity, using fishponds as retention ponds, constructing pumping stations, and building flood diversion culverts. By assessing climate change effects of future projected rainfall increment on the drainage system, simulations were performed to obtain potential inundation extent and depth regarding damage losses for the evaluation of each proposed approach. The results indicated that the potential inundation-prone lowland area, in which drainage is relatively difficult, must be analyzed assessing climate-change impact to implement appropriate flood management approaches.