Research On Xiaoqing River Detention Basin Flood Routing Mathematical Model And Water Balance

Our country has always suffered from floods since ancient times. Before 1949 the frequency of the flood ranked first in all types of disasters in the past two thousand years. After the founding of New China, our country launched a large-scale of flood control projects, while continully increased the plan intensity of the non-structure measures. It was always arranged detention basin or flood discharge channel to vent for excess flood in flood control planning arrangements of the major rivers. Detention basins continue to be developed and used in recent years. Numerical simulation analysis was carried out on the flood detention zone. A series of rules determined by the flood moving process can give a guide to the scheduling aspects of flood detention basin and make the flood loss to minimize.In this paper, Xiaoqing River detention simulationg model is established based on the two-dimensional unsteady flow equations.In this model, finite volume method is applied to discrete the modeling base equations, irregular grid is used to arrange the entire model grid and infiltration rate is obtained by he Green-Apmt infiltration curve.The actual elevations of embankments and bridges are input in the model while the small bridges, culverts and the western sandpit have all been modeled and consolidated. The inflow positions are located near Zhang Fang village and the outflow takes place at Dongci village nearby.12 positions are selected to validate this model with different flood frequencies of 20 years and 50 years.Compared the calculated values with the designed values, the alidation results are basically consistent. Then this model is applied under two embankment conditions, respectively current condition and planing without safety zone condition for Zhuozhou city. The food frequencies are selected 20 year frequency and 50 year frequency. The flood situation can be analyzed with the flood process and the vector flow field of different moments in the entire duration. Meanwhile submerged areas of Zhuozhou city is counted under different computing conditions.Sometimes it may occur water imbalance with the current calculation model which means that some unit body appears negative depth resulting in a false flows. In this paper, a unit of water flow correction method is proposed to improved the computing model. And the details of the entire operation of the process has been introduced in the paper. In the last, the inflow volume is respectively constracted with the the total calculation volume of the former model and the later improved model. The validation results show that the revised calculation model has a certain practical application value.