考虑水库泄水影响的逐网格汇流演算方法

Routing method of confluence considering the influence of reservoir drainage at grid scale

为将网格新安江(Grid-XAJ)模型更好地应用于受水库泄水影响地区的洪水模拟及预报,以横排头流域为研究区域,基于水库真实地理位置,利用分段马斯京根(MK)法、逐网格MK法、逐网格Muskingum-Cunge-Todini(MCT)法对比分析水库泄水对模型汇流计算的影响。结果表明:3种方法对洪峰的模拟情况均较好,率定期与验证期全部洪水的平均合格率均为100%;逐网格MK法与分段MK法全部洪水的平均径流深合格率均为76.9%,小于逐网格MCT法(84.6%);与分段MK法相比,逐网格MCT法与逐网格MK法可以反映上游水库泄水对汇流过程中流量在流域中时空分布的影响;逐网格MCT法在逐网格MK法的基础上进一步考虑了下垫面河道的真实情况;总体而言,逐网格MCT法对于受水库泄水影响流域的洪水预报具有较强的适应性和可靠性。

In order to better apply the Grid-Xin’anjiang(Grid-XAJ)model in the flood simulation and forecasting in areas affected by reservoir discharge,the effect of reservoir discharge on the model confluence calculation was compared between the segmented Muskingum(MK)method,grid-based MK method and grid-based Muskingum-Cunge-Todini(MCT)method,based on the real geographical location of the reservoir in the Hengpaitou Watershed.The results show that the flood peak simulation of the three schemes is good,and the average pass rate of all the floods in the periodic and verification period of each scheme rate is 100%.The average pass rate of runoff depth in the grid-based MK method and segmented MK method is 76.9%,which is lower than that of the grid-based MCT method,84.6%.Compared with the segmented MK method,grid-based MCT method and grid-based MK method can reflect the influence of upstream reservoir discharge on the spatial and temporal distribution of discharge in the catchment process.Grid-based MCT method further considers the real situation of the underlying river channel on the basis of grid-based MK method.In general,grid-based MCT method has strong adaptability and reliability for flood forecasting in basins affected by reservoir drainage.