Study On Simulation Of Flood Inundation In Fengle River Basin Under Climate And Land Use Change

Flood is one of the most serious natural disasters that human society is facing today.Flood has caused huge casualties and economic losses,which has been widely concerned by the international community and academic circles.With the global climate change and the intensification of human activities,the occurrence of floods becomes more and more frequent.Simulation of flood inundation under climate change and land use change is not only an important application of GIS technology in river basin hydrology,but also an important content of flood control and flood fighting.Therefore,this paper takes Fengle River basin as the study area and applies FLUS land use simulation model,SWAT hydrological model and MIKE FLOOD hydraulic model to simulate flood inundation under different scenarios in Fengle River basin.The research conclusions are as follows:(1)From 2000 to 2015,the area of urban land,forest land and water area increased by 16.17 km~2,1.63 km~2 and 1.80 km~2,respectively,while the area of cultivated land and grassland decreased by 19.50 km~2 and 0.10 km~2,respectively.Using FLUS model to predict land use in 2030,the change trend of land use in 2030 is basically consistent with that in 2000-2015.(2)After the deviation correction,the temperature and precipitation data of 2022-2040 under the RCP4.5 scenario and the land use data of 2030 simulated by the FLUS model were input into the calibrated and validated SWAT hydrological model to predict the runoff of 2022-2040,and the total runoff decreased in 2022-2040.On the seasonal scale,spring,summer and winter all showed a decreasing trend except autumn.On the monthly scale,the runoff in April,September and November in 2022-2040 will increase by 6.72%-28.86%compared with that in 1986-2005,with the least increase in April,and the greater increase in September and November is related to the increase in monthly precipitation.(3)The Gumble distribution was used to compare the daily maximum flow in different return periods for flood frequency analysis.Compared to the year of 1986-2005,the daily maximum flow in different return periods during 2022-2040 showed an increasing trend.The bigger the flood return period is,the greater the daily maximum flow increases,and the greater the possibility of future floods.(4)MKE FLOOD model is applied to simulate Fengle River basin flood inundation in different scenarios.Under normal circumstances,the maximum flooded area in 2027 and 2040 is 67.14 km~2 and 56.78 km~2,respectively.The maximum inundated area of 5 year,10 year,30 year,50 year,100 year and 500 year recurrence interval floods is 52.14 km~2,63.66 km~2,76.56 km~2,86.46 km~2,90.12 km~2 and 92.19km~2,respectively.The upper reaches of Sigutan River and Gucheng Si River,the middle and lower reaches of Zhangjiadian River and Zhangmuqiao River are prone to water overflowing and flood overflowing due to their lower banks.The middle and lower reaches of Fengle River have the most severe flood inundation,the widest inundation range and the largest inundation depth.