The use of sand column in recharge reservoir to reduce sea water intrusion.

Excessive groundwater extraction, causing the occurrence of water loss under the surface of the soil, causes the sea water pressure to land larger, resulting in sea water intrusion. To overcome seawater intrusion, one way that can be done is by adding groundwater using a sand column placed at the bottom of the recharge reservoir which connects directly to the aquifer layer. The purpose of this study was to analyze the effectiveness of using sand columns in recharge reservoirs as a buffer for sea water intrusion. This research is a numerical modeling study using SEAWAT program simulation, which will produce data in the form of sea water intrusion. Parameters used are: the number of sand columns, isochlor concentration, where each parameter consists of 3 variables and the reservoir water level is 8 variables. The simulation results obtained show that by increasing the number of sand columns and reservoir water height, the length of seawater intrusion can be shortened.by using of three sand columns and reservoir water level of 97 cm, the results show a decrease of 2281.05% compared to those without using a sand column. [ABSTRACT FROM AUTHOR]