Numerical simulation and optimal exploitation scheme for the karst groundwater recourses system of Fengshui spring basin in Zibo region, Shandong Province，China 

The Fengshui karst spring system is the most important groundwater resources for water supply in the area of Zibo, Shandong Province. Due to serious industrial pollution of the previous water source in Dawu area, a new water source located in Liuzheng area is identified and explored to carry out the re-assessment of the karst groundwater resources availability and then come up with an optimal exploitation scheme. Through understanding hydrogeological conditions and establishing conceptual model of the study area, a three-dimensional, heterogeneous and anisotropic karst water model has developed by using FeFlow software, based upon the equivalent continuum porous media theory and using the data derived from the 16 year borehole monitoring data. The results of water balance calculation from 2000 to 2015 shows that the average groundwater recharge of the study area is 1.0447×106 m3/d and the average discharge is 8.027×105 m3/d, with a net positive surplus of 2.420×105 m3/d. The model prediction results for the optimal pumping of the karst groundwater suggest that, (1) To maintain the current groundwater exploitation with 3.591×105 m3/d in the Dawu area, the maximum exploitation should be 5.5×104 m3/d in the Liuzheng area, and the total exploitation in the Liuzheng-Dawu area is up to 4.141×105 m3/d; (2) To meet the need of maximum permissive groundwater exploitation in the Liuzheng-Dawu area, the maximum exploitation quantity can be decreased to 3.341×105 m3/d for Dawu area and increased to 8×104 m3/d for Liuzheng area.