THE SEAWATER INTRUSION CONTROL BY GROUNDWATER RECHARGE FACILITY

Abstract

The effect of a detention-infiltration facility to groundwater salinity intrusion is examined by observation and using MODFLOW. MODFLOW is the model for groundwater analysis. MODFLOW was applied in Eastern Sendai area. By observation, it was confirmed that there are salinity intrusion. Utility of detention-infiltration facility was confirmed. Furthermore, when infiltration facility is installed over the seawater wedge, it cannot decrease saltwater effectively. Therefore, it is needed to monitor seawater wedge before installing infiltration facility. The optimum surface area and depth of infiltration facility is less than 0.6 km² and 12m, respectively. Increasing saltwater by land-use change can decrease by installing infiltration facility. The graphs of this result are useful indices to install an infiltration facility.