Vulnerability of groundwater resources from agricultural activities in southern Kuwait

Abstract

Kuwait is an arid country situated in the northwestern corner of the Arabian peninsula, which suffers from limited natural water resources. Groundwater in Kuwait is mostly saline, except for some freshwater lenses in the northern part and some brackish zones existing in the south and southwest. With an annual average rainfall of 120 mm and evapotranspiration of around 2266 mm, the recharge of aquifers by rainfall is negligible. Fresh groundwater lenses with total dissolved solids (TDS) less than 1000 mg/l are exploited for potable purpose, and brackish groundwater with TDS between 1000 and 5000 mg/l is used for irrigation. The objective of this study was to assess the impact of irrigation on the salinity and the drawdown of groundwater in the Al-Wafra farms area in southern Kuwait. As a result of the gradual increase of the groundwater extraction for irrigation, the quality and quantity of the groundwater in the aquifers have been depleted. Water levels in the southern part of Kuwait have declined and the maximum declination of 20 m was observed at the center of the farm area. About 35% of the irrigated water was lost due to evapotranspiration, and the rest infiltrated back to the aquifer through the vadose zone, resulting in an increase in the TDS level in the groundwater up to 14,000 mg/l. Such an increase was observed at several locations within the farming area. As a part of this study, two numerical models were developed to predict the groundwater quality as well as the drawdown. The relation between the well locations, decline in water levels, variations in groundwater quality and the transmissivity distribution were interpreted, and the results of the numerical simulations were compared and scaled with field observations. It is estimated that, in the next 5 years, if irrigation is continued at the present rate, then only about 20% of the existing wells will have a TDS level of less than 7500 mg/l.