The Runoff Simulation In Hongan River Basin Based On SWAT Model Under Changing Environment

The study of runoff simulation in the changing environment has become a hot topic in our society.Time and space climate change and human activity influence as the expression form and important composition of the change environment have the decisive influence on the runoff change of the basin.Based on climate change and human activities,it is very important to analyze the impact of runoff and analyze the contribution rate of both.It is also a difficult point to study the simulation of runoff in a changing environment.As the domestic rapid economic development,population explosion,the continuous improvement of social average per capita water consumption,and water pollution is increasingly serious,the per capita water resources gradually reducing,intensified the contradiction between man and water,these cases are run against the sustainable development of water resources.The study of runoff simulation and runoff forecast in the changing environment plays an important role in promoting the current situation of hydrological water resources,rational and efficient utilization of water resources,and improving the ecological environment and economic problems in the basin.This study HongAn jianhe river basin as study area,the runoff simulation using the SWAT model,sensitivity analysis was carried out on the model and parameter calibration and verification,and apply Yu Hongan jian river basin,to simulate the changes of runoff in a changing environment.This study mainly draws the following conclusions:(1)this study summarizes and summarizes the domestic and foreign research status of distributed hydrological models,the domestic and foreign research progress of the SWAT model and the problems existing in the domestic application of the SWAT model.In this paper,we applied SWAT model to study the honganjian river basin,and based on the existing spatial data and attribute data of honganjian river basin,we established the SWAT spatial database and attribute database.The subwatershed division and hydrological response unit generation of the research area were completed by analyzing the terrain and water system extraction with the aid of ARCGIS.The watershed was divided into 12 sub-basins and 83 hydrological response units.The sensitivity analysis of the parameters is made,and the sensitivity range of parameter is determined.The monthly runoff data of dongzhuang water station is used to determine and verify the simulation data.(2)the SWAT model parameter sensitivity analysis,using the "upstream hydrological station measured runoff data from 1972 to 1981 of the model calibration,the measured runoff data from 1982 to 1991 for model validation.The results showed that the relative error of the calibration period and the verification period was lower than-0.10 in the monthly runoff simulation,and the determination coefficient R2 was greater than 0.8,and the efficiency coefficient ENS were all greater than 0.7.In the daily runoff simulation,the relative error of the calibration period and the verification period is lower than-0.10,and the determination coefficient R2 is greater than 0.6,and the efficiency coefficient ENS is greater than0.5.The simulation of monthly and daily runoff in SWAT model has achieved satisfactory results.(3)it can be seen from the analysis of the annual runoff changes in the basins under different climate scenarios that the impact of precipitation changes on runoff is higher than that of temperature on runoff.For every 10% increase in precipitation,the average runoff increased by 18.3%.For every 1oC increase in temperature,the average runoff decreased by 4.1%.(4)were studied in 1985,2000 and 2015,the third phase of runoff change of land use in the same climate situation,it is concluded that the climate environment the same situation,in 2000 under the land use of runoff is the largest,followed by 2015,the smallest is the runoff under the land use in 1985.(5)analysis of extreme runoff rate is under the situation of land use change: the scene under three(grass)average annual runoff,maximum value followed by the scene two(forest),scene a minimum value of annual runoff(land).(6)land use and climate change have resulted in varying degrees of runoff,among which land use change is significantly greater than that of climate change.In terms of annual runoff,about 90 per cent is caused by land use changes,while climate change affects runoff only 10 per cent.Therefore,in the future of the great river basin water resources management.