台灣地勢陡峭導致河道坡度大，地狹人稠，且地處亞熱帶季風氣候區，每年季風與颱風帶來之豐沛降雨往往使台灣各地傳出淹水災情，造成許多的人命與財物損失，而近年來極端氣候愈演愈烈，洪水與乾旱巨災事件只增不減，所以關於治水的議題重要性劇增，洪水不再是以往單純使用工程手段就可以解決的，搭配淹水潛勢圖進行非工程方法減災漸漸被重視。 透過國內外洪水潛勢圖資比較，看出各國對於治理洪水的制度不同，可作為台灣治理洪水發展或洪水保險制度的借鏡；亦比較現今國內外常用之淹水分析模式，看出不同的地理條件不同，所適用之模式亦不相同。 本研究選定新竹中港溪及附近流域為研究區域，於蒐集流域相關水文地質資料後，建立流域之2D地表水數值模擬模型，利用WASH123D(WaterShed Systems of 1-D Stream-River Network, 2-D Overland Regime, and 3-D Subsurface Media)二維漫地流模擬淹水潛勢圖並搭配暴雨頻率分析，使後續之洪水危害度分析模組達到改善台灣洪水設施及洪災保險制度等非工程減災方法之目的。 ;The geography of Taiwan changes drastically over a short distance resulting in steep-slope rivers. Taiwan is located in the Subtropical monsoon climate area. Monsoon and typhoon always bring in abundant rainfall that spread the floods throughout Taiwan , causing a lot of human life and property damages every year. Extreme weather has intensified in the past decade. Floods and drought events have increased. The important issue of flood control is increasing dramatically. Flood control can no longer be achieved simply with engineering means. Non-engineering methods of flood control, in conjunction with the delineation of potential flood-disaster maps, have gained a great deal of attention. Comparing potential flood maps of domestic and foreign countries, we can infer the difference of flood control policy in international communities. This can serve as a guidance for managing floods or promoting flood insurance policies. We can also compare different flood simulation models used by difference countries. The applicability of flood simulation models depend on geographical, topographical, and landscape conditions. In this study, the Chungkang - River and the nearby watershed were selected as the study area. The data of the 2D surface water in the watershed were established after collecting the relevant hydrological and geological data of the watershed. WASH123D was employed to conduct two-dimensional diffuse flow simulation to delineate flooding potential map with the analysis of rainfall frequency. The flood hazard analysis module was then employed to improve Taiwan flood facilities, fine tune flood insurance system, and apply other non-engineering disaster reduction methods.
