Emerging from the depth: preliminary clues on groundwater upsurge in the coastal city of Zliten, Libya

This study focuses on localized groundwater flooding (GWF) in Zliten, Libya. The GWF caused significant damage to approximately 200 houses, leading to the relocation of 80 families. The lack of scientifically identified reasons for this groundwater upsurge poses challenges for effective remedial actions. To investigate the flooding causes, remote sensing techniques were employed. Preliminary results showed fluctuations in groundwater storage (GWS) over the past two decades in Zliten. Notably, a sustained decrease in groundwater levels occurred from 2008 to 2012. Sea Level Rise (SLR) patterns varied across Libya’s coastline, with Zliten experiencing an estimated mean SLR of 2.8 mm/yr. Satellite-based findings suggested a consistent decline in Zliten’s water storage capacity. It is possible that (i) overuse of the aquifers has disrupted the confined aquifer, leading to a groundwater upsurge, and/or (ii) recent extensive groundwater pumping activities have placed the confined aquifer under pressure exceeding atmospheric pressure. As a result, water has surged in the wells and even the land to relieve the pressure and reached its potentiometric level. An End-Member Mixing Analysis (EMMA) of water samples from the affected areas could further validate this hypothesis by determining the contributions of surface water, groundwater, or groundwater from the confined aquifer.