基于栅格型新安江模型的中小河流精细化洪水预报

Fine-scale flood forecasting for small and medium-sized rivers based on Grid-Xin’anjiang model

为提高中小河流洪水预报的精细化水平,以栅格型新安江模型(GXM)为基础,考虑沿程水流再分配、库塘坝蓄泄及河道特征对产汇流过程的影响,采用针对性的定量化模拟方法,并基于模型参数与下垫面特征的定量关系,对模型参数空间分布进行推衍。以安徽横江为例,对GXM的精细预报能力进行验证。结果表明:GXM不仅可以实现对屯溪出口断面洪水过程的高精度预报,也可以不经重新率定,实现对流域内部嵌套断面洪水过程的高精度预报;GXM能够预报流量、土壤含水量、流速等不同水文要素的时空分布,可为中小河流洪水防控提供丰富的预报产品。

The Grid-Xin’anjiang model(GXM)is used to improve the flood forecasting accuracy for small and medium-sized rivers.The effects of the flow re-allocation process,storage and discharge of small reservoirs and ponds,and channel features on the runoff generation and concentration are considered in this study.With the quantitative simulation methods,the spatial distribution of model parameters is estimated based on the quantitative relationship between model parameters and underlying surface characteristics.The GXM is applied to the Hengjiang River located in Anhui Province for verifying its fine-scale forecasting capability.The results indicate that the model can satisfactorily forecast not only the streamflow at the outlet,but also the flood process at any interior grid cells without model recalibration.Besides,the spatiotemporal distribution of different hydrological elements,including the discharge,soil moisture and flow velocity,can be obtained from the GXM.GXM can provide abundant forecasting products for flood control of small and medium-sized rivers.