Effect of a hyperarid climate on groundwater salinity: A case study of the Ouargla shallow aquifer (Northern Sahara, Algeria)

Abstract

Groundwater resources are typically affected by both global climate factors and anthropogenic activities. This influence is most apparent in arid and semi-arid climates of the Saharan desert. With rising temperatures and minimal precipitation, climate variability in these regions has a particularly significant and systemic impact on the chemical composition of shallow aquifer water. In this regard, our study aims to evaluate the climatic effects on groundwater in Saharan environments, using the Ouargla basin as a prime example. Water samples taken from 45 observation piezometers in our selected study area in February and June 2021 were used to assess the overall impact of inter-annual climate variations on salinity within this shallow groundwater basin. The obtained results show that groundwater located in the first three meters of shallow aquifer depth is directly influenced by surface climate. This pattern holds true for both observed seasonal periods. Stratification indices within the saturated zone were found to be positive, indicating an increase in groundwater salinity at lower depths and negative in shallower depths. This suggests a direct climate influence on this groundwater. These findings can be used to enhance sustainable development strategies in such environments, notably by quantifying salt accumulation and efficiently managing salinity exchange between saturated and vadose horizons.