Study On Emergency Groundwater Supply Based On Coupling Model Of Social Economy And Water Resources

Due to the influence of monsoon climate,the uneven distribution of surface water resources in the humid region of southern China,coupled with excessive dependence on surface water supply,leads to the problem of seasonal water shortage easily in this region.Groundwater resources are relatively stable and have the function of dynamic regulation.Emergency groundwater supply is an important way to alleviate the contradiction between supply and demand of water resources.It is of great significance to comprehensively consider the interaction between social economy and water resources for realizing long-term coordinated development of urban systems in emergency groundwater supply.Taking Nanchang City as an example,the coupling conceptual model of social economy-surface water-groundwater is established by using the system dynamics method(SD).SD-SWAT-MODFLOW coupling program is developed on the basis of predecessors,which realizes dynamic coupling calculation of social economy subsystem,surface water subsystem and groundwater subsystem in time and space.Based on the analysis of water resources supply and demand under different economic and social development scenarios,the emergency groundwater supply scheme is put forward,and the groundwater emergency water source area is evaluated by Analytic Hierarchy Process(AHP).This paper mainly obtains the following understandings and conclusions:(1)The social economy and water resources are closely related,which mainly includes the supporting and restraining effects of water resources on the social economy,and the stressing and promoting effects of the social economy on the water resources.Social economy-surface water-groundwater coupled system mainly includes water resources supply and demand balance subsystem and emergency groundwater supply subsystem.Coupling simulation of social economy,surface water and groundwater can be realized through interaction variables such as surface water withdrawals,groundwater extraction,available surface water resources and emergency groundwater extraction.(2)Based on the social economy-surface water-groundwater coupling conceptual model,the social economy model and hydrological model are built by using Vensim and SWAT-MODFLOW coupling simulation program.The SD-SWAT-MODFLOW coupling program is written by FORTRAN programming language to realize the dynamic coupling simulation of social economy and water resources in time and space.The coupling model can simulate the spatio-temporal evolution of the social economy-surface water-groundwater coupling system well.(3)The coupling model is used to forecast the water resources supply and demand in the next 12 years under the status quo,developing and water-saving scenarios respectively,and it is found that there is an imbalance between water resources supply and demand under all scenarios.In 2030,water resources shortage is the most serious,and the maximum demand for emergency groundwater supply is 48.73×10~4,72.63×10~4 and 27.3×10~4m~3/day respectively.Emergency groundwater supply will result in a groundwater level drop of 24%to 94%of the aquifer thickness,which will have a negative impact on the water resources and the surrounding geological and ecological environment.(4)AHP is used to carry out the comprehensive evaluation of emergency groundwater supply,which mainly considers water resources,social economy and environmental impact.The evaluation result shows that the Youkou water source is the most suitable for emergency groundwater supply,but it also needs to implement water-saving measures to reduce the amount of emergency groundwater exploitation,so as to reduce the adverse impact on the surrounding geological and ecological environment.