Evaluating groundwater salinity patterns and spatiotemporal dynamics in complex endorheic aquifer systems

Area of Science:

• Hydrogeology
• Environmental Science
• Geochemistry

Background:

• Endorheic aquifer systems in arid regions face significant salinity challenges, impacting water resources and agriculture.
• The Bahira plain in Morocco is a case study for groundwater salinity issues in such environments.

Purpose of the Study:

• To comprehensively assess salinity sources and evolution in both unconfined and confined aquifers of an endorheic basin.
• To understand the hydrogeochemical processes controlling groundwater quality.

Main Methods:

• Analysis of major ions and stable isotopes from 213 groundwater samples.
• Application of a binary mixing model to evaluate salinity variation and ionic imbalances.
• Spatial distribution analysis of salinity.

Main Results:

• Unconfined aquifers show hyper-salinity (up to 60,000 μS.cm⁻¹) from evaporation and soil leaching.
• Confined aquifers have lower salinity (500–3000 μS.cm⁻¹) with regional recharge.
• Water-rock interactions and high evaporation rates are key drivers of salinity.

Conclusions:

• Groundwater salinity in endorheic basins is controlled by a combination of climatic, geologic, and anthropogenic factors.
• Findings offer insights for sustainable water management in arid regions globally.
• Distinguishing recharge sources is crucial for managing groundwater quality.