Evaluation of Adaptation Strategies for Urban Flooding in Central Taipei City in Taiwan

The urban areas have been rapidly developed in Taiwan in recent years. The expanding urban areas and the increasing population, especially in the metropolitan Taipei city, result in surface runoff discharge during typhoons or rainstorms. When the surface runoff exceeds the capacity of drainage systems of the city, the urban inundation and property losses occur. The urban flooding risk assessment is a useful tool for the decision-making in flood damage mitigation. In general, hazard and vulnerability are two main factors for the risk assessment. In the present study, the Center Taipei City (CTC) is chosen as the study area. The A1B scenario simulations proposed by IPCC are used to compare the flood risks between the present situation and future condition which is under climate change scenario. The ArcGIS is used to yield the flood potential information and the flood risk for the return period of 10, 25, 100 and 200-year flood. The simulated results revealed that the increasing water storage to meet the regulation of the Taipei City government would effectively reduce the effects of climate change on the decreasing inundation areas. The adaptation strategies will also reduce the high-risk areas in the CTC according to risk assessment. The adaptation strategies composed of increasing the water storage in urban areas and reducing the social vulnerability of flooding area are the effective way for the flood risk reduction in urban area.