Numerical Modeling of Emergency Karst Groundwater Well Field and Prediction of Variations of River Seepage in Fangshan District,Beijing

In order to evaluate the emergency karst groundwater well field in Fangshan District,Beijing,the numerical model of groundwater flow was established on the basis of the conceptualized equivalent continuous medium.The simulation of groundwater interaations with river and spring were executed by using the sub-programs river and drain packages of MODFLOW.The simulated results are reasonable by comparing the simulated groundwater tables with the observed processes.Simulated and predicted results indicate that groundwater are closely connected with surface water in emergency karst groundwater well field areas.After the emergency extraction,the river changes from the groundwater system discharge into the river to recharge groundwater.The results can provide the basis for rational development and utilization of emergency karst groundwater well field.