Groundwater Resource Management in Coastal Aquifers

Coastal aquifers represent a critical buffer between terrestrial freshwater systems and the marine environment, supplying water to millions of people while moderating the impacts of sea-level rise and storm surges. These sedimentary and fractured-rock formations contain variable layers of sand, gravel, silt and limestone, through which freshwater is stored and transported. Management challenges arise from competing demands—agricultural irrigation, urban supply, ecosystem conservation—and from biophysical threats such as saltwater intrusion, land subsidence and contamination from urban runoff. Effective stewardship relies on integrated monitoring of groundwater levels, quality and recharge rates, coupled with predictive modelling of freshwater–seawater interactions under scenarios of climate change and changing abstraction patterns. Adaptive strategies include controlled extraction regimes, managed aquifer recharge using treated wastewater or stormwater, artificial barriers to saltwater movement and land-use planning that safeguards recharge zones. International examples demonstrate that policies combining hydrogeological insight, community engagement and regulatory frameworks can sustain coastal freshwater resources while preserving ecological integrity and supporting socio-economic development.

Research from Nature Portfolio

Recent studies have advanced the use of remote sensing and numerical modelling to map salinity gradients across coastal aquifers at continental scales, integrating satellite gravimetry with in situ salinity probes to reveal zones of freshwater depletion and impending saltwater encroachment. Novel isotopic and tracer experiments have quantified the rates of saline-water intrusion following storm-driven overwash, informing dynamic management of pumping schedules in vulnerable barrier-island systems. In parallel, field trials of managed aquifer recharge using permeable infiltration basins have demonstrated the potential to augment natural recharge by up to 50 per cent in coastal plains, reducing chloride concentrations by creating freshwater mounds that impede lateral saline-water fronts. These interventions have been coupled with decision-support tools that adapt real-time pumping limits to tidal cycles, offering a blueprint for resilient coastal groundwater governance.

Groundwater Resource Management in Coastal Aquifers publication trend

The graph below shows the total number of articles in groundwater resource management in coastal aquifers across all publications each year (not limited to Nature Index journals).

Technical terms

Aquifer: A geologic formation of permeable rock or sediment that holds and transmits groundwater.

Saltwater intrusion: The movement of saline water into freshwater aquifers, typically driven by groundwater extraction or sea-level rise.

Managed aquifer recharge (MAR): The deliberate enhancement of groundwater replenishment using natural or engineered infiltration methods.

Hydraulic conductivity: A measure of a material’s ability to transmit water through its pore spaces or fractures.

Salinisation: The process by which water or soil becomes enriched in dissolved salts, often reducing its suitability for human or agricultural use.

References

1. Challenges in groundwater resource management in coastal aquifers of East Africa: Investigations and lessons learnt in the Comoros Islands, Kenya and Tanzania. Journal of Hydrology Regional Studies (2016).
2. Seawater intrusion in the coastal aquifers of East and Horn of Africa: A review from a regional perspective. Scientific African (2020).