Research On Flow Field Evolution Under Over Exploitation Of Shallow Groundwater In Xunfeng Area

The area of this study is the piedmont alluvial-proluvial plain area of Xiuwu.The main aquifer in the study area is pore aquifer of Quaternary loose rocks,which has abundant water resources.However,in the actual development and utilization process,large-scale exploitation without scientific planning has resulted in imbalance of groundwater exploitation and recharge in local areas,resulting in local over-exploitation areas,especially in the area of Xun Fengling,forming a regional funnel with an area of 164000 mu and depth of 28.9m.Therefore,in order to achieve sustainable development of groundwater resources and prevent excessive exploitation of groundwater resources in overexploited areas,so as to achieve the balance of recharge and discharge of groundwater and restor tecological environment,it is extremely urgent to harness the over-exploited areas.This paper mainly carries out the following research:(1)Analyzing the relationship between groundwater level and rainfall,artificially exploited quantity in the study area,and analyzing the influence of different influence factors on groundwater level;(2)Analyzing the characteristics of hydrochemical changes in the study area;(3)Establishing groundwater mathematical model according to groundwater condition in the study area;(4)According to different mining conditions,combined with mathematical model of groundwater.To simulate the groundwater hydrodynamic flow field over a five-year period(2019-2023).The main conclusions are as follows:(1)The annual change of groundwater level in the study area is greatly influenced by rainfall.However,the interannual variation is greatly affected by the amount of artificial exploitation,and with the increase of exploitation,the groundwater level continues to decline.(2)During the period 2011-2018,the chemical type and chemical ion composition of groundwater in the study area changed.Due to the formation of the overdraft funnel area,the flow of groundwater to the overdraft area is intensified,the p H value is lowered,calcium and magnesium ions are increased,the quality of groundwater is deteriorated,and the total hardness of groundwater in the overdraft area is increased.(3)Based on the hydrogeological conditions and recharge and discharge characteristics of the study area,combined with groundwater simulation software,the mathematical model of groundwater within the study area is established.Through simulation,parameter adjustment and verification,the mathematical model of groundwater meeting the actual hydrogeological conditions is finally obtained.(4)2019-2023 is selected as the prediction period for simulation.One is the unrestricted exploitation and utilization of groundwater.As a result,the water level continues to drop,and the groundwater has been in a negative equilibrium state,falling by about 1-3.5m compared with the predicted initial water level.The second is to carry out pressure mining or even limited mining in the overmining area of Houfeng,with the limited mining volume of 7 million m~3/a.As a result,the groundwater level has partially risen,about 1-5m higher than the predicted initial water level.The recovery of the water level in the overmining area is obvious,indicating that the groundwater recharge in the research area is greater than the discharge and is in a positive equilibrium.The results of limited mining in over-exploited areas can provide scientific guidance for local control of over-exploitation of groundwater and rational utilization of groundwater resources.