Assessment of vulnerability to marine intrusion using the GALDIT method in the coastal aquifer of Las Tablas, Azuero Peninsula, Panama

Abstract

Water scarcity is a challenge due to the pressures and conflicts that arise from its use. Panama, a tropical country with extensive coastlines and home to 50 % of the population, faces the effects of climate change that drastically affect groundwater availability, specifically in the Azuero region. Due to this problem, the issue of sustainable use of groundwater resources takes on special relevance, with the district of Las Tablas, a major hub of economic and tourism activity, largely supplied by groundwater. To assess the vulnerability of its coastal aquifer, the GALDIT method was applied. This method integrates information from six parameters that govern the aquifer's intrinsic susceptibility to marine intrusion, facilitating the calculation of the Vulnerability Index. As a result, maps of the aquifer's current vulnerability to marine intrusion were constructed, as well as projections to 2050, under different climate change scenarios. Most of the sector studied presents a low vulnerability to marine intrusion. Only in a strip approximately 2 km from the coastline is moderate or high vulnerability observed, with the highest values in the northeasterly zone, where the piezometric level is lowest and the electrical conductivity of water is highest. The generated maps will be relevant to water resource managers in their decision-making, as they will facilitate the sustainable management of aquifers, creating monitoring programs for groundwater quality and extraction volumes.