The Change Tendency of Short-term Rainfall Characteristics and The Possible Measures in Urban Drainage Systems

近年来，短时暴雨频繁袭击城市，给城市居民的财产和生命造成了严重的损失。认为城市排水系统能力不足和全球气候变暖引起的气候系统变化是造成这些灾害的主要原因。由于城市排水系统的流域面积相对于河流而言很小，洪水到达的时间也很短，因此，在全球气候变暖的背景下，短期降雨强度的变化对城市排水系统的规划和管理具有重要意义。根据长期降雨记录，确定了由于全球变暖而导致的短期降雨强度的可能变化。根据短期降雨强度的评价结果，建立了设计暴雨。针对已识别的降雨形势变化的影响，探讨了提高城市排水系统能力的可能措施的选择标准和选择过程。

Recent years, short-term storms have struck urban areas frequently and caused heavy damages not only on residents' property but also human lives. The main reasons that caused the damages have been considered due to the insufficient capacities of urban drainage systems and the changes in climate system caused by the global warming. It is crucial to urban drainage system planning and management how the short-term rainfall characteristics will change with the global warming going on because urban drainage systems usually have much small basin areas in comparison with rivers, and the flood arrival time is especially short.This study has focused on the evaluation of the impacts of the changes in short-term rainfall intensity on urban drainage systems. The possible changes in short-term rainfall intensity due to global warming have been identified based on the long-term rainfall records. The design storms then are created from the evaluation result about the short-term rainfall intensity In correspondence to the impacts of the changed rainfall situation identified, the selection standard and selection process of the possible measures has been discussed to improve the capability of unban drainage systems.