Vulnerabilidad hidrogeológica en la zona costera de Jacó, Pacífico Central, Costa Rica

Abstract

En las últimas dos décadas, el Pacífico Central de Costa Rica experimentó un fuerte aumento en el desarrollo urbanístico y turístico, lo que representa una mayor amenaza a la calidad del agua subterránea. El objetivo de este estudio fue el generar una propuesta del Mapa de Vulnerabilidad Hidrogeológica de los acuíferos de Jacó, utilizando la metodología GOD. Para esto, se elaboraron perfiles geológicos y se realizó comprobación de campo. Se evidencia que el área de estudio está conformada por a) un acuífero costero detrítico, poroso y libre, albergado en la planicie aluvial de Jacó y, b) un acuífero fracturado en las rocas basálticas del Complejo de Nicoya, libre en la zona montañosa y subyaciendo la formación detrítica en la zona central, donde el agua subterránea se integra a la del acuífero detrítico, conformándose en un mismo acuífero. La zona del acuífero aluvial obtuvo una vulnerabilidad moderada, en tanto que el fracturado una vulnerabilidad baja. Se propusieron recomendaciones de manejo.

Analysis of the threat of groundwater contamination in the Jacó aquifer, Central Pacific, Costa Rica

“…In the alluvial plain, the aquifer is unconfined and is housed in unconsolidated alluvial and colluvial materials and, thus, detritic (SENARA, 2002. In the hills, the water transits through fractured basaltic and sedimentary rocks and then heads towards the alluvial plain of the study area and, probably, integrates with the groundwater of the unconsolidated formation due to the absence of an impermeable separating barrier layer, thus uniting and becoming a single aquifer (Gómez-Cruz et al, 2019). The recharge in the alluvial plain can be produced by direct infiltration of rainfall (SENARA, 2002), by lateral contribution from the hills, and from influent rivers, in sections where the rivers provide water to the aquifer (Gómez-Cruz et al, 2019).…”

“…In the hills, the water transits through fractured basaltic and sedimentary rocks and then heads towards the alluvial plain of the study area and, probably, integrates with the groundwater of the unconsolidated formation due to the absence of an impermeable separating barrier layer, thus uniting and becoming a single aquifer (Gómez-Cruz et al, 2019). The recharge in the alluvial plain can be produced by direct infiltration of rainfall (SENARA, 2002), by lateral contribution from the hills, and from influent rivers, in sections where the rivers provide water to the aquifer (Gómez-Cruz et al, 2019). The detritic aquifer, which covers 30.5 % of the study area, shows a thin layer of soil, a water level between 0.5 and 5 m deep, a groundwater direction towards the southwest (Figure 2) and an intermediate degree of hydrogeological vulnerability to contamination (Gómez-Cruz et al, 2019).…”

“…The recharge in the alluvial plain can be produced by direct infiltration of rainfall (SENARA, 2002), by lateral contribution from the hills, and from influent rivers, in sections where the rivers provide water to the aquifer (Gómez-Cruz et al, 2019). The detritic aquifer, which covers 30.5 % of the study area, shows a thin layer of soil, a water level between 0.5 and 5 m deep, a groundwater direction towards the southwest (Figure 2) and an intermediate degree of hydrogeological vulnerability to contamination (Gómez-Cruz et al, 2019). The section of the aquifer in igneous and sedimentary rocks located in the hills presents low vulnerability, mainly due to the fact that the groundwater level is between 70 and 100 m deep (Gómez-Cruz et al, 2019).…”

“…The detritic aquifer, which covers 30.5 % of the study area, shows a thin layer of soil, a water level between 0.5 and 5 m deep, a groundwater direction towards the southwest (Figure 2) and an intermediate degree of hydrogeological vulnerability to contamination (Gómez-Cruz et al, 2019). The section of the aquifer in igneous and sedimentary rocks located in the hills presents low vulnerability, mainly due to the fact that the groundwater level is between 70 and 100 m deep (Gómez-Cruz et al, 2019).…”

“…The coastal aquifer of Jacó is an important source of drinking water for a large part of the resident (permanent) and floating populations despite the existence of potentially contaminating anthropogenic activities, mostly related to the tourism sector (Orozco, 2015). The aquifer in the plain has also a thin layer of soil, a water level between 0.5 and 5 m deep and, therefore, a medium level of hydrological vulnerability to contamination (Gómez-Cruz et al, 2019). Between 1995 and1997, an incipient process of saline intrusion was identified (Servicio Nacional de Aguas Subterráneas, Riego y Avenamiento [SENARA], 2000), probably related to the over-extraction of groundwater.…”