Comparison and analysis of calculation of Bridge backwater based on Mike21 hydrodynamic model

The construction of bridges and other structures across the river will affect flood discharge capacity local water potential river.Based on navier-Stokes equation MIKE21FM hydrodynamic module, this paper carries out two-dimensional numerical simulation part Shixi River. By optimizing grid near piers to reduce difference brought by terrain generalized real river, it simulates analyzes length curve yong-high Yong-water under different frequencies,the Nash-Sutcliffe efficiency coefficient relative error analysis are used verify rationality results. results can accurately reflect changes level, It provides a theoretical basis for impact analysis.