| At present,one of the important non-engineering measures in the disaster prevention and control of flash flood is using hydrological model for mechanism analysis and hydrological calculation of flash flood,so that the disaster information of time,place,magnitude,inundation and possible loss information of disaster can be obtained beforehand.In China,the area of hilly areas is so wide that the climate characteristics and underlying surfaces of different small basins are all different.The flood disasters have significant regional differences,so we should select suitable hydrological model according to the characteristics of small watershed.In addition,the topography of small watershed in hilly area is complex and changeable,which makes the accuracy of underlying surface data greatly affect the prediction results of hydrological models.Identifying uncertainty caused by quantitative modeling data has important practical significance in improving the level of flood forecasting and warning.Based on this,the performance of 5 hydrological models with varying degrees of complexity for flash flood forecasting in different small-scale watershed as well as its applicability to the catchments characteristics were analyzed,in order to summarize the applicable conditions of different hydrological models.On this basis,we choose HEC-HMS distributed hydrological model to analyze the impact of DEM resolution and watershed subdivision in Luanchuan basin.By constructing the uncertainty quantification framework based on ANOVA variance decomposition,this study also quantitatively analyzes the contribution of accuracy of modeling data in flash flood forecasting.The contents of the article and the results of the study are as follows.Total of 5 hydrological models with different levels of complexity,including API model,XAJ model,DHF model,TOPMODEL and HEC-HMS model,are used to compare the flood simulation of 14 small watersheds in hilly area.The results show that HEC-HMS has the strongest applicability to the flash flood forecasting in this study,and other models perform differently in different basins.According to the climate characteristics and hydrological data conditions of small watershed,we summarize the applicable conditions of each hydrological model to provide scientific suggestions for selecting models.By setting up 10 m,30m,50 m and 100 m total four DEM resolution and 35,25,15 and 5 total four watershed subdivisions,the HEC-HMS distributed hydrological model is selected to study the change of spatial parameters and hydrological simulation results under different DEM resolutions and watershed subdivisions in Luanchuan basin.The results show that the high resolution DEM or the detailed watershed subdivision does not make the peak simulation reach the best,but it can ensure the error distribution is centralized and the model performance is relatively stable.At the same time,the influence of DEM resolution and watershed subdivision on flood process is obvious,because the Nash coefficient decreases with the decrease of data precision.Based on the ANOVA method,the uncertain quantized framework of DEM resolution and watershed subdivision is constructed with 16 kinds of data precision combined schemes to identify the uncertainty sources and quantify their contribution from the relative error of flood peak discharge and Nash coefficient respectively.The results show that the flood peak simulation is more sensitive to DEM resolution,while the flood process simulation is more sensitive to watershed subdivision.There is a strong interaction between DEM resolution and watershed subdivision,and we should pay attention to the matching relationship of data accuracy in modeling,so as to provide reference for the selection of HEC-HMS model data for flood forecasting in Luanchuan basin. |
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