由於土地開發的快速變遷，破壞地表本來具有滲透能力，當暴雨來臨時，使得原先設計之排洪措施無法負荷地表所增加逕流量。並因經費與用地取得困難，以致於修建先前所設置之排洪措施不易。因此，其改進方法有二：一為調節水流型，目的在降低洪峰流量及遲滯洪峰到達時間。通常使用滯洪池與滯洪霸等來達到此目的。二為增加入滲型，目的在增加入滲減少地表逕流。一般使用停車場、人行道之透水表面、綠地等來達到此目的。 本研究的目的即將集水區，分別於不同地點設置滯洪池，探討滯洪池設計大小與地點選取最佳化配置方法。並對於滯洪池的設計中增加入滲的考量，期望能增加滯洪池的滯洪效益與減少工程經費的花費。 研究中發現設置滯洪池控制局部集水區逕流量即可達成滯洪效果，且所需滯洪體積將小於滯洪池設置在最下游處。由分散多個滯洪池設置，有助於集水區內大範圍洪峰流量控制。滯洪池設計時，應採取整個集水區洪峰流量管制，以防因為多個局部滯洪池設置，造成下游地區聚集性衝擊。 Because of the rapid development of land, urban area soil permeability is decreased. When storms come, the existing drainage system can no longer handle the increased runoff discharge. Due to the limitation on funding and available land, it is unlikely to overhaul the original system. There are two alternative ways to help to solve the problem: The first is to regulate the flow. The idea is to reduce the peakflow and delay its arrival. The common methods to achieve this goal are to use detention basins and detention ponds. The second is to increase the infiltration of land surface as well as sewer pipes so as to reduce the runoff. To do that, the pavement of parking spaces, sidewalks, and sewer pipes are designed to be able to infiltrate water. The goal of the research is to employ not only a single collection zone for the water, but to having detention ponds in different places, and to decide on its optimal size and location. In addition, the infiltration ability of the detention ponds is being considered. This research indicates that to achieve detention effect only needs to construct detention ponds to control regional watersheds, and comparing to the detention ponds located at the downstream, the needed detention capacity will be lower. The separated detention ponds help to control the peakflow of a broad area. When constructing detention ponds, the designing should restrain the peakflow of the whole watershed, in order to prevent the congregated impact of the down stream area caused by the separated detention ponds arrangement.
