Applicability Of Conceptual Hydrological Model Indifferent Watersheds

Due to the joint influence of climate change and human activities,the process of water cycle and the temporal and spatial distribution law of water resources changed in varying degrees,which intensified the complexity of hydrological characteristics and the uneven distribution of water resources.Conceptual watershed hydrological models play an important role not only in the field of water cycle research,but also in other fields related to water cycle.No matter the decision-making of major issues such as hydrology and water resources,environment and ecology,or flood control and drought resistance,it is inseparable from the support of hydrological models.The research of hydrological models is an important research content in the field of hydrology.Through in-depth analysis of the physical causes of hydrological phenomena,we can fully grasp the internal laws of hydrological phenomena,and can make qualitative or quantitative scientific analysis and prediction of hydrological situation in history or in the future.It is an important support for water conservancy project planning and construction,optimal allocation of water resources and safe,efficient and sustainable utilization.Therefore,how to select the hydrological models suitable for a specific watershed is very important.The difficulty of applying the hydrological model as the basic concept and operational data of hydrological mechanism is relatively low,so it can be used to simulate the hydrological process with a certain degree of generality and efficiency.It was widely used in scientific research and production practice.In view of this,based on 41 typical conceptual hydrological models,this paper simulated the runoff of rivers in the alpine mountainous area in the upstream of Shiyang River Basin from 1990 to 2003 and Lijiang River Basin from 2008 to 2016,and evaluated the applicability of the models in different climate regions from the aspects of the structural characteristics,evapotranspiration simulation,runoff component proportion and change characteristics of the models.The main conclusions are as follows:(1)Overall,most of the 41 models achieved good simulation results in the Lijiang River Basin and the upstream of Shiyang River Basin.Among the models with evaluation indexes KGE and R~2 above 0.5,Dv within 10%and RMSE below 5,the total number of models in Lijiang River Basin was more than 30,and most of the upstream of Shiyang River were more than 30.Among them,MODHYDROLOG,IHACRES,GR4J and Hillslope were recommended models for hydrological simulation of Lijiang River Basin;FLEX-IS,HYMOD and FLEX-I models were recommended for hydrological simulation in the upstream of Shiyang River Basin.(2)The runoff simulation results of 41 models in the Lijiang River Basin and the upstream of Shiyang River Basin were quite different.On the one hand,the total number of excellent models in the Lijiang River Basin was higher than that in the upper reaches of the upstream of Shiyang River Basin,and the overall simulation of 41 models in the Lijiang River Basin was better than that in the upper reaches of the upstream of Shiyang River Basin.On the other hand,the optimal five models of the two watersheds were different,but there were two same models of Collie River Basin 1 and VIC model in the worst five models.Therefore,there were models that were not applicable to the two basins,but the model applicable to the Lijiang River Basin was not necessarily applicable to the upstream of Shiyang River Basin.(3)From the perspective of the structure composition of the model,the structural complexity of the model,such as the number of reservoirs and parameters,was not the key index to determine the applicability of the model.It was mainly the matching between the structure function of the model and the characteristics of the watershed that affected the simulation results of the model.As far as the Lijiang River Basin was concerned,the MODHYDROLOG model with the mixed runoff generation mechanism of excess infiltration and full storage,as well as the IHACRES and GR4J model with fast and slow runoff division were applicable to the hydrological simulation of the Lijiang River Basin.For the upstream of Shiyang River Basin,the FLEX-IS,HYMOD and FLEX-I model simulated by fast and slow runoff showed excellent simulation results in the upstream of Shiyang River Basin.(4)From the evapotranspiration simulation of the model,on the one hand,the accuracy of evapotranspiration simulation was one of the factors affecting the runoff simulation.The runoff simulation results of models with excellent evapotranspiration simulation level were usually excellent;On the other hand,the evapotranspiration simulation ability of the model was not the decisive factor for the performance of runoff simulation.Some models had a high level of evapotranspiration simulation,but the performance of runoff simulation was not good.In the optimal model,the evapotranspiration simulation level of Lijiang River Basin was lower than that of the upstream of Shiyang River Basin,and the deviation value was more than 100 mm higher.In the worst model,the evapotranspiration simulation level of Lijiang River Basin and the upstream of Shiyang River Basin was poor,and the deviation values were quite different.(5)The division and treatment of runoff components in the model directly affected the runoff simulation results of the model on the watershed,and reflected the matching degree between the model and the runoff generation mechanism of the watershed.Therefore,it has become a key part of the model for the watershed.In the Lijiang River Basin and the upstream of Shiyang River Basin,the proportion difference between surface runoff and underground runoff simulated by the optimal model was small,and the simulation effect of runoff components was good.In the worst model,there was a wide gap between the proportion of surface runoff and underground runoff in the Lijiang River Basin and the upper reaches of Shiyang River Basin,and the simulation level of runoff components was not ideal.