Application of GIS and AHP Analysis for the Delineation of Potential Groundwater Bearing Zones in Fractured Rock Aquifers

Abstract

Groundwater extraction accounts for around 29% of Puerto Rico’s water demand. About 50% of the withdrawn water from aquifers serves the needs of “Non PRASA” communities mainly located in the central province of the island. In this scenario, it is essentially needed an effective approach to asses and explore abundant and sustainable groundwater resources, to better serve future water demand. This study presents an approach to locate, delineate and estimate the recharge of groundwater bearing zones using the Geographical Information System (GIS). The methodology was used to pinpoint groundwater potential zones in fractured rock aquifers located in Rio de La Plata Watershed. To achieve the study objective, various thematic layers of hydrology, hydrogeology and geomorphology parameters were processed into raster features in ArcGIS 10.5 software. A weight overlay of these parameters was then analyzed by means of an Analytic Hierarchy Process (AHP), generating a groundwater potential map. Groundwater bearings zones identify by the model demonstrate agreement with USGS and PRASA well inventory. Results validate the relevance of GIS and AHP as effective tools for assessment, management and future groundwater exploration in the island. Key Terms - Analytic Hierarchy Process, Hydrogeology, Geographic Information System, Groundwater Potential Zones.