ABSTRACT
More importantly though, extensive soil sealing as a consequence of urban growth decreases the infiltration capacity of territory and subsequently increases the volume of surface runoff resulting from local rainfall events. Insight in the future drainage characteristics is essential in order to take appropriate actions including proper land use management to ensure adequate urban drainage performance. Thus, the increasing impervious surface ratio seems to be due to the development of contiguous urban areas: the urbanness of a major portion of the built-up areas has increased and therefore more cells are classified as urban built-up. Although Beijing is mainly suffering from water scarcity the megacity also suffers significant impacts from urban flooding. To cope with the increasing pressure on the drainage system in combination with the increase in precipitation, the Chinese government has recently adopted the concept of 'sponge city' in which widespread application green infrastructure is promoted to better cope with extreme rainfall events.
