湖泊型水库环库实时洪水预报方法研究OACSTPCD

The construction of lake-type reservoirs alters the subsurface conditions and river system structure within the controlled watershed,thus impacts the runoff production and concentration mechanisms.According to the characteristics of runoff production and routing of basin surrounding lake-type reservoir,a combined flood forecasting model containing the impermeable area of reservoir surface and the disrupted runoff-producing area surrounding the reservoir is developed,and the calculation methods of runoff production and concentration in different areas are proposed.Taking the Xianghongdian Reservoir as a study case,the comparative analysis of flood simulation results are carried out.The results indicate that,(a)the accuracy of the combined flood forecasting model is significantly improved than that of the traditional Xin'anjiang Model,with the Nash-Sutcliffe efficiency coefficient improved by 0.1,and the relative error of flood volume and flood peak reduced by 5.3％and 2.9％,respectively;(b)the relevant parameters of the combined forecasting model,such as impervious area and coefficients related to runoff production and concentration,can better capture the characteristics of fragmented sub-basins and the composition of incoming flood hydrograph;and(c)the direct production of inflow from the reservoir surface occupies a major proportion,representing the fourth runoff component in addition to surface,interflow and subsurface flows.Overall,the proposed method can provide modelling support for real-time flood forecasting in watersheds with lake-type reservoirs and has promising potential for further application.