Numerical Simulation And Restoration Of Groundwater In Liaocheng Over-Exploitation Area

With the development of the economy and society,the global shortage of water resources is becoming more and more serious.China's per capita water resources are small,and the shortage of water resources is more prominent.Groundwater is the important source of water,and people's uncontrolled exploitation of groundwater has triggered a series of environmental and social problems.Liaocheng City in Shandong Province is located in the severely water-deficient area in the north of China.The per capita water resources is only 8% of the national average.The over-exploited groundwater has made the groundwater over-exploitation zones gradually expanded,as well as large-scale graoundwater depression cone.The over-exploitation of groundwater has caused a series of problems that severely restrict the local socio-economic development.The restoration of groundwater in the over-exploited area is an important task in the current groundwater management in Liaocheng City.Based on Visual MODFLOW model,some rerearches were carried out to simulate the groundwater over-exploitation area in Liaocheng City.Firstly,on the basis of deep understanding of hydrogeology,groundwater recharge,drainage,runoff conditions and boundary conditions in the study area,the corresponding hydrogeological conceptual model was established.Then according to the actual situation of groundwater system in Liaocheng over-exploitation area,a groundwater simulation model based on Visual MODFLOW was constructed,the model parameters were calibrated by the data in 2015,and validated by the data in 2016.The results show that the model can simulate the groundwater dynamic processes in the study area,and the hydrogeological parameters have a good fit for the actual situation.Finally,through the groundwater balance analysis in the over-exploitation area,the water storage changes of the groundwater system are obtained,which also verified the rationality of the groundwater model.According to the groundwater remediation and treatment plans of Liaocheng City,13 groundwater remediation schemes were designed based on the reduction of groundwater exploration,replacement of water source and artificial groundwater recharge,including 5 schemes of reduction of groundwater exploration,5 schemes of water source replacement,and 3 schemes of artificial groundwater recharge.The benchmark scheme is no repair measures.The calibrated Visual Modflow model was used to predict the repair effect under the desighed 13 schemes.The results showed that if there is no control of over-exploitation,the groundwater level in each county would continue to decline.On the other hand,all the repair solutions could slow down this trend.The simulation also indicated that the water source replacement schemes have the best effect on groundwater remediation,and 30% of the water source replacement scheme can reduce the groundwater reduction by more than 50% within 3 years.Finally,this paper presented a combinaed scheme of 30% water source replacement + 10% reducing groundwater exploration + 30% recharge,which could make the groundwater system keep a dynamic stabilization in Liaocheng over-exploitation zone.