Implications of groundwater development and seawater intrusion for sustainability of a Mediterranean coastal aquifer in Tunisia

Using Analytical Hierarchy Process and Multi-Influencing Factors to Map Groundwater Recharge Zones in a Semi-Arid Mediterranean Coastal Aquifer

“…Major crops grown in the study area are vegetables (potatoes, tomatoes, strawberries, etc. ), vineyard plantations and citrus [8,11]. The region is characterized by a semi-arid climate (average annual rainfall: 420 mm) with Mediterranean influence.…”

“…Demand for fresh water resources is noticeably increasing as a result of growing agricultural water demand, population growth and rapid industrialization. Therefore, groundwater abstraction has become an integral component of many water management plans worldwide, including in rural areas of the Western Mediterranean region [4][5][6][7][8].…”

“…The Korba coastal area in northeastern Tunisia is faced with groundwater over-pumping, causing seawater intrusion and degradation of groundwater quality. In this region, groundwater is the primary water source for domestic and agricultural purposes for about 90% of the rural population [2,[5][6][7][8][9] and 50% of urban residents [6,9,10], putting pressure on the aquifer to cope with the rising demand [2,5,9,10]. Groundwater overdraft was identified as a problem in the early 1980s when the Tunisian government called for a reduction of water pumping by encouraging farmers to adopt drip irrigation systems by covering up to 60% of the installation cost [11].…”

“…Groundwater overdraft was identified as a problem in the early 1980s when the Tunisian government called for a reduction of water pumping by encouraging farmers to adopt drip irrigation systems by covering up to 60% of the installation cost [11]. Since then, groundwater levels have continued to decline and seawater intrusion is steadily progressing in most of the coastal areas with the expansion of agricultural lands despite efforts to implement water conservation policies, build recharge dams, transfer water from the north, stop drilling new wells and encourage the re-use of treated wastewater [4,8]. Most of the deficit is observed in the central part of the Korba area where 53% of croplands are irrigated [2,[5][6][7]11].…”

“…The accuracy of the AHP and MIF techniques was evaluated using a receiver operating characteristic (ROC) curve based on the area under the ROC curve (AUC), which includes all the possible decision thresholds from field observations of well yield data and water level depth. Although many investigations have assessed the groundwater resources of the Korba area [2,[5][6][7][8]10,11] none of them have used remotely derived data to demarcate GWRZs in this region. The GWRZ maps facilitate groundwater management through better water balance calculations based on improved estimates of recharge-precipitation ratios to quantify percolation.…”