Study On Coupling Model Of Surface Water And Groundwater Based On HYDRUS-MODFLOW

Surface water,soil water and groundwater are indispensable parts of the interacting and intrinsically connected water circulation system within a certain topographic geological climate.In recent years,with the increase of climate change and the impact of human activities,the hydrological situation is constantly changing.The conversion process between surface water,soil water and groundwater is affected to varying degrees,and the analysis between surface water,soil water and groundwater is analyzed.Transforming relationships and mastering the dynamic process of water resources are of great significance to the evaluation,development,utilization and protection of water resources in river basins or regions.Traditional surface water resources,groundwater resources and conversion assessment methods mostly separate the complex transformation relationship between surface water and groundwater,and it is difficult to reflect the spatial differentiation characteristics of hydrological cycle,water resources formation and evolution process in the sub-area,such as watershed surface hydrology.The model or groundwater model simplifies some of the processes in the hydrological cycle system during the simulation process,resulting in the lack of feedback between hydrological processes and the systematic deviation of the simulation results.Therefore,in order to better simulate the process of mutual conversion between waters,it is necessary to study surface water and groundwater as a whole system from the process,and establish a more comprehensive coupling model of surface and groundwater,and analyze the relationship and dynamics between surface water and groundwater conversion.Variety.Based on the saturated-unsaturated water flow motion model,this paper expands the surface hydrological process and constructs a coupled model of surface water and groundwater in the basin(region)to simulate the surface water and groundwater conversion process in the region.The main research contents and results are as follows:(1)Through the analysis of the unsaturated zone model HYDRUS and the groundwater model MODFLOW,the coupling principle and operation mechanism of the HYDRUS-MODFLOW coupling model are further grasped.At the junction of the diving surface,the HYDRUS model exchanges information on groundwater recharge and groundwater level with the MODFLOW model.MODFLOW receives the recharge from HYDRUS and calculates a new water depth for the next time step,which is used as the HYDRUS model.The pressure head is at the bottom boundary condition.On this basis,the model was applied to the indoor soil trough rainfall infiltration test to simulate the groundwater level,groundwater discharge and soil water potential.The simulation results show that HYDRUS-MODFLOW has a good simulation effect on the water exchange process between saturated and unsaturated zones at a small scale.(2)In order to further verify the simulation ability of HYDRUS-MODFLOW for saturated and unsaturated water exchange,the soil infiltration infiltration test data and the characteristics of the model itself are compared with the typical models of UZF1-MODFLOW and VSF-MODFLOW..When simulated in a small scale,the simulation accuracy of VSF-MODFLOW and HYDRUS-MODFLOW is higher than that of UZF1-MODFLOW;from the simulation efficiency,the simulation efficiency of UZF1-MODFLOWD and HYDRUS-MODFLOW is higher than VSF-MODFLOW;In terms of requirements,the calculations of UZF1-MODFLOWD and HYDRUS-MODFLOW are smaller than VSF-MODFLOW;from the aspect of hydrological elements,HYDRUS-MODFLOW has more hydrological elements than the other two models.Through comparative analysis,HYDRUS-MODFLOW can achieve a better balance between simulation efficiency and simulation accuracy than VSF-MODFLOW and UZF1-MODFLOW.(3)Based on HYDRUS-MODFLOW,expand the surface hydrological processes such as surface runoff,watershed production and flow,and river calculus,and construct a coupled model of surface water and groundwater in the basin(region),and apply the model to Linyi,which has better data conditions.The basin is used to simulate the groundwater level and the flow of the outlet section of the basin.The simulation results show that the simulated values of the coupled model fit well with the measured values,indicating that the model can better simulate the conversion process between surface water,soil water and groundwater in the basin(region)scale,within the basin(region)scale.Water resources evaluation and water resources management have certain reference significance.