Impact of Pumping on Saltwater Intrusion in Gaza Coastal Aquifer, Palestine

Gaza Coastal Aquifer (GCA) is the major source of water in Gaza Strip. Recent studies show noticeable deterioration in the water quality; where chloride, nitrate, sulfate, and fluoride concentrations are exceeding the maximum contaminant levels in most of the wells in Gaza Strip. Many agricultural wells are no longer used due to the high salinity. This high salinity is an indication of a phenomenon called saltwater intrusion which appears mainly in coastal aquifers due to the excessive pumping. This study is an attempt to find out the impact of pumping on the hydraulic head at the coastline of Gaza Strip. To do so, a groundwater flow model was developed for GCA using MODFLOW-2000 based on data from the Palestinian Water Authority (PWA). The model was calibrated based on head observations obtained from PWA and contour maps from literature. The calibrated model was used to simulate the effects of pumping, recharge, and injection on water table elevation. The results show that GCA is sensitive to the above mentioned parameters. Pumping has a great impact on water table elevations. A small decrease in total pumping (pumping from all of the wells) results in a noticeable decline in the areas that have water table elevations below mean sea level (MSL), which is in essence an indication of saltwater intrusion. Similar results were found when decreasing municipal and agricultural pumping. Two potential solutions were simulated; reduction in pumping and the injection of water through wells. These two options eliminated the problem of saltwater intrusion. However, a thorough future analysis should include an economic feasibility study.