Urbanization Pattern and its Impact to Flood Response: A Case Study to Dongguan City in Southern China

Urbanization is the world’ development tendency that has been well observed all over the world. Developed countries have lead this development, but the developing countries experienced a more rapid urbanization in the past decade, such as China. Dongguan city is a newly developed international metropolitan and experienced a very rapid urbanization that is not observed in other place in the world. Urbanization has negative impact to the flood responses, such as increasing peak flow, enlarging runoff coefficient, this requiring bigger flood mitigation engineering measures. In this study, the land use/cover(LUC) of Dongguan city for the past 40 years was first estimated quantitatively by employing the satellite remote sensing images, which is used to analyze the urbanization pattern of Dongguan city for the past decades. Unique urbanization pattern has been found and proposed based on the series of LUC, which is described by the author as Sparking Spots Firing the Prairie Urbanization Pattern. Based on the quantitative LUC changes, its impact to flood responses has been simulated. The hydrological model employed for this simulation is the Liuxihe model which is a physically based distributed hydrological model, and the observed precipitation from 3 flood events was used for the model inputs, and the impact was simulated in three watersheds within Dongguan city. Model parameters were calibrated by using the observed hydrological data in some watersheds with hydrological observations. The results show that the impact of urbanization in Dongguan city is significant, and the flood peak flow has been increased more than 5 times, that is bigger than that reported in other literature.