9. Conclusion

The study area is located in the southwest of Kuwait. It includes 83 wells that produce brackish groundwater from Kuwait Group aquifer. Pumping test analyses revealed that the aquifer is acting as a confined to semi-confined aquifer, and transmissivity ranges between 62.03 and 320.51 m2 /day and increases toward N-NE. The estimated storage coefficient is 7.5 <sup>10</sup><sup>4</sup> .

In the present study, the pH values range from 7 to 7.9, indicating an alkaline type of groundwater. The total alkalinity ranges from 51.2 to 127 mg/l with an average value of 91.39 mg/l. The electrical conductivity values range from 4370 to 8230 μmohs/cm with an average value of 5837 μmohs/cm. Total dissolved solids vary from 3504 to 6366 mg/l, with an average value of 4441 mg/l representing brackish groundwater. The majority of the groundwater samples of the study area exhibited NaCl water chemical type, followed by Na2SO4, and CaSO4 water chemical types, respectively.

The groundwater is very hard, where the average TH is 1826 mg/l as CaCO3. The sequence of the abundance of the major cations and anions is Na<sup>+</sup> > Ca2+ > Mg2+ > K<sup>+</sup> and Cl > SO4 <sup>2</sup> > HCO3 . The dominant hydrochemical facies of the groundwater in the study area is Ca-Na-Cl. According to Gibb's plot, most of the samples of the study area are under the category of rock interaction and few samples are found to have the category of evaporation. Few samples fall in the precipitation-dominance area suggesting the influence of precipitation on the groundwater. Silicate weathering is the dominant weathering process in the study area; however, the carbonate weathering processes are also responsible for the supply of some ionic species to the groundwater. The calculation of the saturation indices revealed that the groundwater is oversaturated with respect to calcite and dolomite and undersaturated with respect to gypsum, anhydrite, halite, and SiO2.

The positive index of base exchange for most of the samples (>98%) indicates that there exists a chloro-alkaline equilibrium, and there is an ion exchange of Na+ and K<sup>+</sup> from water with magnesium and calcium in the rock, except one well, where the value is negative, revealed cation-anion exchange (chloro-alkaline disequilibrium).

Most of the TDS and TH values obtained are beyond the permissible limits making the groundwater of the study area unsuitable for drinking and for various domestic activities.

The suitability of groundwater for irrigation was evaluated based on the irrigation quality parameters like RSC, permeability index, potential salinity, SAR, salinity hazard, magnesium ratio, %Na, and Kelley's ratio. The majority of the groundwater samples exhibited very high salinity to extensively high water salinity class, medium and high sodium water type, respectively, According to the values of these parameters, the groundwater of the study area was found to be used for irrigation under high soil permeability, good drainage, and plants with good salt tolerance should be selected.
