Response Of Hydrological Processes Based On LCM-SWAT Model In Feicheng Basin

In recent years,it has been affected by human activities such as agricultural farming,industrialization,and urbanization.The type of land use and the surface cover are changed in different times and spaces significantly,and the underwater cushion conditions are changed.This change in the lower mat constitutes a human "system interference" that has an important impact on the hydrological process of the basin.This effect is reflected in the change in water thermal condition in the surface,which in turn affects the current production exchange flow mechanism so that the running stream is redistributed in time and space.Temporal and space-distribution changes in hydrological processes can result in biological habitat break,biodiversity sharp decline,and biological variations,thereby further leading to regional ecosystem structure and composition,endangering ecological security.Explore the hydrological process response under the conditions of land use change has become an important way to effectively manage and utilize water resources currently.Temporal and Spatial changes in hydrological components caused by changes in land use changes,which have important significance for the process of understanding the production exchange flow in the basin,and optimizes the land use structure and water resources planning of the basin.This study focuses on the Feicheng Basin in the middle of Shandong.With the support of GIS technology,this study first analyzes the characteristics and historical changes of land use type based on past land use basic data of the area.On this basis,establishing land change model(LCM)to simulate and predict future land use of Feicheng Basin with land use influencing factors.At the same time,the SWAT model is established based on hydrological meteorological data,land utilization data,soil data,and terrain spatial database to simulate the runoff process.Considering the changes in land use in different periods,the quantitative assessment of the annual hydrological process elements and the annual flow of hydrological process under different land use conditions from 1980 to 2025 to get a hydrological response to the change of land use in Feicheng Basin.This study aims to provide a theoretical basis for water resources planning and soil and water conservation planning of the basin.The main conclusions of this study are as follows:(1)The type of land use in the Feicheng Basin is mainly divided into cultivated land,woodland,grassland,urban and rural residential land,waters and unused land.The cultivated land is the most important land use type of the Feicheng Basin,followed by the land of urban and rural residents,the area of the two,accounting for more than 85%of the entire study area.During 1980-2018,the cultivated land area has gradually decreased,and the land area of urban and rural residents has gradually increased trend.Woodland area is reduced after the first increase,starting in 2010,the magnitude of change tends to zero.The grassland area has been rapidly reduced after 2005,and the reduction rate after 2010 is slowly approaching zero.The water and unreleased area increase.At the same time,there is a complex mutual conversion between the types of land use,which belongs to weak balance conversion.The main transformation types are cultivated land and forest land transferred residential land,forest land and grass transfusion land,grassland and waters to the city and township residents.(2)Based on the LCM model to predict land use changes in the study area in 2025.The results showed that cultivated land is still the largest land use type,followed by urban and rural residents,and then the grass area,and other types of other types are relatively small in 2025.The land use area such as cultivated land,woodland,and grassland will continue to decrease.The land and water area of urban and rural residents will increase.The land is basically unchanged,and the resident urban and rural areas are concentrated.(3)The SWAT model was established based on hydrological weather,land use,soil,terrain,etc.in Feicheng Basin.Using SWAT-CUP and SUFI-2 algorithms to analyze the parameter sensitivity and to ratio the parameter of the model,and utilizing R2 and Ens as the applicability evaluation criteria for this model.The simulation results show that R2 is 0.83 and Ens is 0.79 in the calibration period,which shows the model simulation of this paper.In the verification period,R2 is 0.78 and Ens is 0.72,and because the measured range flow data is large,the simulation accuracy is slightly reduced,but the accuracy requirements of the model application have been reached.(4)Land use changes can cause changes in the annual average hydrological elements in the basin and changes in the annual interior runoff,and the change in land use has different effects on the degree of the annual rhizome.The annual range of river basins is small,and the variation of the dry year is relatively obvious.In 1980-2015,the surface runoff of the basin increased,but after 2005,the trend slowdown.At the same time,the underground tract flow has gradually reduced trend.Evaporation exhibits first and then decreased and then increased fluctuation changes.The trend of changes in the annual interior runoff process under the conditions of each land use is consistent,but the flow value generated has a more significant difference at the same time point.Under the conditions of land use in 1980,the flow of flows in the basin was the smallest,followed by the 1995 land use conditions,once again 2005 and 2018,and the largest runoff under land use conditions in 2025.At the same time,the effect of land use changes on the flow of flow is seasonal,and the changes in runoffs are mainly concentrated in the flood stage and the relative changes in low water levels.(5)The reasons for changes in the hydrological process in the study area are mainly caused by the use of urban and rural residents,water bodies to cultivated land,grassland and forest land.The land and roads of urban and rural residents have increased significantly,causing an increase in the inflatable area of the basin,so that the water storage capacity of the surface is lowered,so the amount of the lower infiltration is small,and the surface flow rate is increased.The area of woodland and waters has certain correlations with the amount of evaporation in the basin.The increase in the area of the two will increase the surface vegetation coverage and moisture,thereby increasing evaporation.There is a certain absorption effect on the garden and cultivated land.The reduction in the area of the two causing a decrease in the amount of infiltration under the basin,and the surface flow rate is increased.