Hydrogeochemical and Isotopic Investigations for Evaluation of the Impact of Climate Change on Groundwater Quality, a Case Study of the Plaine of Kasserine, Central Tunisia

Abstract

Located in arid region in Central Tunisia, the plaine of Kasserine is a deep Plio-Mio-Quaternary aquifer representing the most available source of water supply in the region. The increase of water demand with the impact of climate change caused a significance decline in the groundwater quality and quantity. The challenge of this study is to investigate hydrochemical and isotopic data for a better understanding of the groundwater mineralization mechanism and to highlight the link between the impact of global change and hydrochemical aspects in the plaine of Kasserine. To achieve these goals, 19 wells were sampled and several physico-chemical parameters (Temperature, pH, Salinity, Na, K, Ca, Mg, Cl, HCO3, SO4 and ∂2H and ∂18O) were analyzed. Conventional hydrogeochemical techniques and multivariate statistical analyses were performed. The water type of the plaine of Kasserine gradually evolved from Ca–HCO3 to Ca–Na–SO4 suggesting two possible main processes: dedolomization and cation exchange generated by the dissolution of gypsum and dolomite and the precipitation of calcite. Furthermore, data inferred from stables isotopes in groundwater samples indicated that direct infiltration principally ensure the recharge of this aquifer. However, as an arid region, the plaine of Kasserine is threatened by climate change, due to the low and the irregularities of precipitation, leading to the decrease of water table level and deterioration of its water quality. This study help understand the hydrochemical processes of the plaine of Kasserine and assess the impacts of climate change in this arid region for a better monitoring of these valuable resources.