Questionable frequent occurrence of urban flood hazards in modern cities of China

China has been frequently damaged by big floods and suffered from flood hazards, especially in its modern cities. The cities of China have experienced rapid expansion and urbanization since China’s economic reform in 1978. Population increase owing to the relocation of agricultural population to the central city and the ever-enlarging urban area triggered the rapid growth of urban centers (Qiu 2010). These have been resulted by urbanization which has profoundly transformed the spatial pattern of urban land uses and landscapes (Qi and Zhang 2011; Zheng and Qi 2011) during the past five decades which cause a steady increase in flood disasters in China. Floods could be a complex and destructive environmental hazard unless manage properly (Kelman 2005). Urban flood hazards are now happening more frequently than in the past due to the massive urbanization movement and economic development in China. Therefore, urban areas are highly vulnerable partly from the size and density of their population. Recent China relentless urban flood disasters, such as the July 2007 flash flood disasters in Chongqing City and Jinan City of China and the July 2012 flood disaster in Beijing City (Fig. 1), have wiped away large blocks of homes and claimed many lives. In urban areas of China, flood hazards are not often caused by absolute surplus water alone, but are also due to the irrational land use structure and pattern and the lack of consideration of physical environment during urban expansion, which turn useful precipitation into flood (Shi et al. 2005). There is no doubt that many local government and urban dwellers have a low awareness of flood hazards and vulnerabilities and are uncertain how to reduce vulnerability or to respond to a flood-related threat. Because of climate change, increasing frequencies of abnormal rainfalls coupled with environmental degradation caused by urbanization are likely to trigger more flood hazards in future in the urban areas of China, although the issue has already got the attention and concerns of the Chinese government and many scholars. Therefore, a top priority in