Modelling the effect of high level of total dissolved solids (TDS) for the sustainable utilization of brackish groundwater from saline aquifers in Kuwait

Groundwater resources in Kuwait are almost brackish to saline. There is a concern that the shallow aquifers in Kuwait are polluted with high levels of salinity. The brackish groundwater lenses of the utilized aquifers in Kuwait are strategically important for the agricultural and industrial sectors. These lenses float above saline water bodies. It is the aim of this study to simulate the impact of skimming brackish lenses on the vertical movement of saline water in the utilized aquifer. In order to achieve this aim, pumping tests were conducted on the wells of the study area using Tartakovsky–Neuman method. The results showed that the average transmissivity and specific yield are 330 m2/day and 12%, respectively. The results of the pumping tests were fed into a density-dependent flow with solute transport model to simulate the fate of saline water (with TDS values from 10,000 to 43,000 mg/l) in the utilized aquifer under pumping conditions. The modelling results show that controlling the vertical movement of deeper saline water can be achieved by locating the well screen alongside most of the saturated thickness that includes both brackish and saline water bodies. Only the salinity of the area around well W-2 exceeded the limit of 10,000 mg/l when the total pumping rates from all the wells were 6624 m3/day. This means that the sustainable yield of the aquifer in the utilized zone of the study area is about 5746 m3/day (2.1 Mm3/year) after eliminating the pumping rate of well W-2. The elevated final salinity of the pumped water at this well is influenced by the value of the initial salinity of this well, which was high at 9519 mg/l prior to pumping.