Urban Water Process Observation and Analysis: A Case Study in Shenzhen of Southern China

Urbanization is the world development trend after World War Two, which is more rapid in the developing countries in the past decades. For this reason, lots of megacities have been formed, and Shenzhen City in southern China is one of them. Due to rapid urbanization and social development, megacity surface has been changed dramatically, such as higher density of road network, more complex spatial structure of high buildings, residential areas, and factories. Furthermore, more underground drainage system was built to adapt the increasing flood quantities. For this reason, the flood hydrological process has been altered largely, and observation to the flood hydrological process under this changing environment is imperatively needed for better flood hydrological modeling and adaptation to the changed flood responses. In this study, flood hydrological process observation has been tried in Shenzhen City in the past years in the area where urban flooding is serious and frequent. The hydrological variables observed includes inundation depth and range, flow velocity, and precipitation. Precipitation observation was done by automatic rain gauges and weather radar, while the other variables are observed semi-automatically by field survey. Hydrological processes of several flood events were observed and the data collected. Based on these observation, the hydrological formation processes is analyzed and summarize, which is quite different from that in an undisturbed watershed. This finding is very helpful for proposing the adaptive hydrological model for simulating/forecasting urban flooding.