Urban flood and waterlogging and causes analysis in Beijing
摘要
In this work,the urban flood and waterlogging problems in Beijing were discussed based on the socio-ecologic statistical data and hydrological and meteorological data. Firstly,the results show that the urban waterlogging has become the major type of urban floods in Beijing during the past 50 years. The spatial distribution of waterlogging sites had an outward expansion tendency accompanied by the rapid urban expansion. The artificial depressions in urban areas became the black spots for urban waterlogging because of the land use change and urban micro-topography change. The waterlogging sites had an increasing trend due to the effects of the climate change and urban development. Secondly,the formation mechanism of urban flood and waterlogging was discussed from the perspective of urban water cycle system. The precipitation pattern over the urban areas was changed due to the effects of climate change and rapid urban development. The precipitation in flood season and precipitation extremes both showed a decline trend,whereas the precipitation intensity for short duration precipitation events showed an increasing trend. Additionally,the changes in underlying feature due to the rapid urban development caused the changes in the rainfall-runoff characteristics,which may cause the changes in regional hydrological processes and water resources amounts. Overall,the increasing risk of urban flood and waterlogging was affected by the frequent extreme precipitation events,the changes in drainage pattern,land use/cover change and urban microclimate characters due to the climate change and urban expansion. The increasing vulnerability was also caused by the low standard in waterlogging elimination and drainage control,the deficiency in urban infrastructure and emergency management capacity,which caused the decrease of urban comprehensive response to the urban floods and waterlogging problems.