基于动态水位流量关系的水动力洪水预报模型研究

Application of Dynamic Relationship Between Water Level and Discharge in Hydrodynamic Flood Forecasting Model

鉴于下边界条件对水动力洪水预报模型精度的影响,采用提高下边界条件的质量来提高洪水预报精度,在考虑中下游地区洪水易受变动回水顶托影响的基础上,提出了动态处理水位流量关系下边界的方法,即利用最新信息,并采用分段线性拟合的方法动态拟合新的水位流量关系作为下一时刻的边界条件进行洪水预报,使模型边界具有一定的实时修正功能。在资水流域水动力洪水预报模型中的应用表明,该方法预报精度较高。

As the downstream boundary condition has great impact on the accuracy of hydrodynamic flood forecasting model, this paper improved the precision of flood forecasting by raising the quality of lower boundary condition. A new method to deal with the relation of water level and discharge dynamically was proposed based on considering the backwater influence and flood fluctuation in the mid downstream river section. It takes advantage of the latest obtained information to dynamically piecewise linear fit the new relation of water level and discharge as the lower boundary of the next time step, so the model has real time correction function. Finally, it was applied to the hydrodynamic flood forecasting model in Zishui basin. The results show that the accuracy of flood forecasting has been significantly improved.