Efficiency Analysis of LID on Reducing Urban Flood
|關鍵字:||低衝擊開發(LID);二維漫地流模式;都市淹水;Low-impact development (LID);Overland flow module;Urban flood|
Located in northwest side of Pacific Ocean, Taiwan straddles between tropical and subtropical divided. In summer and fall seasons, many typhoons hit Taiwan. Also the monsoon between April and June brings large amount of rain in Taiwan. With special geographic condition, many floods occur that affect inhabitants of the island. By urbanization increasing, it enhances great development in industry and business but on the other hand, it destroyed the environment hugely. To mitigate urban flooding, the government dedicates on building or extending more hydraulic facilities to solve those problems. However, for extreme powerful rainfalls or frequently occurring minor rainfall, those hydraulic facilities had no special efficiency. Low-impact development (LID) technique is developed by U.S. two decades ago. The concept is to recover the hydrologic and geographic condition to the situation of pre-urbanization, by increasing infiltration and decreasing imperviousness to reduce surface runoff. Overall, LID is widely practiced world-wide and has to been found to have great performance. Recently, the government in Taiwan acquires the foreign experiences and is about to publish the LID manual to deal with the inundation issue. In the past, the research of LID focused on analyzing the reduction of surface runoff or micromanagement urban drainage. In this essay, it not only analyzes the reducing of urban drainage but also simulates overland flow to investigate the efficiency of LID. The results show that LID can reduce flood in an urban drainage under the condition of less than 10-year return period rainfall.