台灣南部地區淹水原因分析之研究

Abstract

氣候暖化、極端氣候變化劇烈，台灣南部地區地勢低平，且沿海地區因為超抽地下水，造成地層下陷，每逢大雨時節，例如: 颱風、梅雨季節，溪水暴漲、大水宣洩不及，均造成當地居民重大的生命財產損失。 綜觀所蒐集的淹水致災原因當中，可以瞭解到最容易致災的情況為:規劃、設計、維護與管理問題，排水相關工程設施之維護不良、設計不佳、設計防洪標準不夠等問題，佔了36.36% (48/132)。第二易肇災者為：內水無法排出，佔21.97% (29/132)。主要係由台灣南部地區之地勢低平、低窪、排水先天性條件不佳等，由於極端氣候造成天氣型態改變，降水時間縮短、延時短、降雨集中、強度高、造成尖峰流量偏高，區域內無法短時間消耗超量之洪水。排水設施無法負荷，造成內水無法順利排出，導致大範圍淹水發生。 綜合治水思維核心價值在於降低河川負擔，使得河川可以在既有基礎上承受更大規模之洪水事件。就規劃層面而言，綜合治水對策的工程實施方式涵蓋流域全體，非集中於河川整治，而所採行策略包括減洪、蓄洪與避災等。

Due to global warming, extreme climate change, the level in Southern Taiwan area is low and coastal area causes subsidence because of groundwater extraction when heavy rain come, for example, Typhoon and Plum rain season. Stream surge and over-flooding cause the heavy loss about property and life of residents.

In conclusion of these flooding disaster reasons, it can be understood that the easiest flooding disaster reason is the problem of plan, design, control, and management. These drainage facilities are maintained not well, designed bad, under the standard of flood protection. And this problem is 36.36% (48/132). The secondary one , hard discharging of inner water, is 21.97% (29/132). It is because of low-lying and bad congenital conditions in Southern Taiwan area, extreme climate changes the weather patterns, short precipitation, short rainfall duration, rainfall centralization, high intensity, and the higher peak discharge, the areas can not deal with excessive flooding instantly. The inner water can not discharge smoothly because of drainage facilities hard-working , let the large-scale flooding happen.

Comprehensive water management thinking, the core value is reducing the load of river. It can suffer larger flood events based on existing foundation. For the part of plan, the project embodiment of comprehensive water management strategy includes all the watershed , not part of rivers. And the strategies are flood mitigation, flood storage, and escaping.