Minghong Chen,Hongwei Fang,Guojian He,Feng Yang, China Agricultural University, college of water conservancy and civil engineering, chenminghong@cau.edu.cn
Beijing, capital of China, is a typical city short of water resources. Beiyun River, as the most important drainage basin of Beijing, flows over the east of Beijing city. Rainfall in this watershed is remarkably uneven in temporal distribution. Most of the rainfalls concentrate in several storms in the flood season, causing flood rising sharply and dropping steeply. To manage water resources requires mastering the characteristics of hydrology processes of this catchment. In the study, the distributed hydrological model DWSM is applied to simulate the hydrological processes in storm events. It is proved to simulate hydrological processes reasonably well by calibration and verification. From the simulation results for rainfall of different frequencies, we find that flood peak appear earlier when the rainfall intensity is greater. The peak flow discharge, as well as runoff coefficient increases synchronously with rainfall intensity. The regime for the operation of reservoir dams and floodgates are applied in this model to change hydrological processes and store flood water. The regulation of reservoirs not only increase the amount of available water resources but also effectively reduce the peak flow at the outlet of Beijing area and lighten the risk of flooding in lower reach.
Keywords: Beiyun River; water resources; hydrological processes; DWSM model; rainfall