Modeling Seawater Intrusion and Sea Level Rise Effects on the Coastal Aquifer of Northern Honduras

Seawater intrusion of coastal aquifers is a concern in coastal communities worldwide. Its effect diminishes the availability of freshwater supplies. The intrusion could be the result of a combination of stressors that include excessive overpumping of groundwater, reduction of groundwater recharge, and potential sea level rise. The intrusion is defined by the encroachment of an “interface zone” inland (also referred to as the “halocline”). This study addresses the increasingly seawater intrusion in the city of La Ceiba, Northern Honduras. The thriving economy of this region is expected to progressively aggravate the need for freshwater supplies to support urban growth and intense agricultural development.  Groundwater is a main water source in the region and therefore its protection from contamination and a sustainable management are crucial to the future of the region.

In order to scope future scenarios of intrusion, a predictive assessment was implemented using the analytical solution of the Ghyben – Herzberg model to estimate the position of the halocline under current and future conditions of groundwater withdrawal, climate change and sea level rise. Climatic and hydrogeologic information and characteristics (e.g., infiltration rates, porosity and hydraulic conductivity) were estimated from field evaluations and limited literature. Results and analysis forecast a wide range of halocline locations and effects on the region; for instance, the combination of continued overpumping with drier years and sea level rise increases should lead to serious socio-economic crises. Considerations to implement sound water resources management plans are hereby described.