Study on Hydrological Calculation Model of Flood Control in the Middle and Lower Reaches of the Chuhe River under the Background of Urbanization

Abstract

The traditional method of hydrology and water conservancy calculation is based on the assumption of natural runoff, while the applicability of method has weakened in the urbanization-affected river basins. The paper carried out research on hydrological calculation model of flood control in the middle and lower reaches of the Chuhe River under the background of urbanization. On the basis of the analysis of flood characteristics in river basins, the hydrological calculation model framework of flood control in the middle and lower reaches of the Chuhe River is constructed, which includes five modules: design rainstorm calculation, runoff calculation, regional flow concentration calculation, river-network confluence calculation and lake-reservoir regulation calculation. The parameters of runoff generation, overland flow concentration, hilly area flow concentration and river-network confluence are determined. Process simulation of the flood water levels and discharges in the middle and lower reaches of the Chuhe River in 1991 and 2008, which are the years with heavy rains, is conducted. The flood simulation of June 1991 shows that the error of water level is -1cm ~ + 8cm, and the error of discharge is +26 m3/s. The flood simulation of August 2008 shows that the error of water level is -8cm ~ + 2cm, and the error of discharge is -9 m3/s. The overall simulation results are relatively stable with all the calculation errors within the allowable range, and the results fit the facts well.