GCMs simulation-based assessment for the response of the Mediterranean Gaza coastal aquifer to climate-induced changes

Abstract

In the Eastern Mediterranean countries, groundwater contained in coastal aquifers is the predominant water source for supplying water. The Mediterranean Gaza coastal aquifer in Palestine is showing alarming signs of depletion due to climate change and human-caused influences that substantially impact the hydraulic performance of the Gaza coastal aquifer. The climate statistical modeling and the downscaling of the ensemble global climate model under the representative concentration pathway (RCP) scenarios of RCP 2.60, 4.50, and 8.50 refer to a future decreasing trend in the precipitation and an increasing trend in the temperature. The stochastic model refers to an average decrease of -5.2% in the rainfall every 20 years that coincides with the RCP scenarios that show a decrease in precipitation between 0 and -5%. The rate of temperature increase over the next 20 years is defined at +1 degrees C, which closely matches the RCP results. As a result of human fast-paced activities, groundwater consumption is expected to rise by nearly 55% by the end of 2040, to around 193 million cubic meters, with a substantial withdrawal trend in southern provinces of the Gaza Strip. Consequently, the aquifer model predicts that subsurface water levels might fall at a rate of -2.50% per year, reaching a level of around -27.77 m below the mean sea level (MSL) by 2040. Alternative water supplies, such as desalinated seawater and treated wastewater, with annual maximum volumes of 110 and 16.5 million cubic meters, respectively, are expected to perfectly recharge groundwater resources of the Gaza coastal aquifer at an annual rate of about +3.65% to meet a groundwater table level of around -5 m below the MSL by 2040.