(Introduction):

In Costa Rica, more than 70 % of the public drinking water supply comes from groundwater sources. In the coastal city of Jacó, on the Central Pacific Coast of Costa Rica, tourism activity is essential for economic development and groundwater represents a source for supplying tourists and residents.

(Objective):

This research aims to characterize the threats of groundwater contamination to the coastal aquifer of Jacó due to human activities, based on land use analysis, characterization of potential pollution sources and, estimation of the floating population related to tourist activity.

(Methodology):

An inventory of potential pollution sources was carried out through the location of human/anthropogenic activities. Potential point, diffuse and linear sources were classified based on the Pollutant Origin Surcharge Hydraulically (POSH) method, as activities with high, medium and low potential generating pollutant load (threat)

(Results):

Of the total potential sources, 0.5 % correspond to activities with high potential, 14.0 % medium potential and 23.5 % low potential, and 62.0 % null potential. Out of 129 point pollution sources, 64.3 % were classified as medium threat activities due to the storage and handling of potentially polluting chemicals. Although the sources of high threat are those of lesser occurrence in the study area, they can generate greater negative impacts on groundwater resources. These are located mainly in the urban area of the city where the floating population reaches more than 12 000 people during the holidays, so their potential for pollutant loading could rise during this period.

(Conclusions):

The results will be considered in territory planning, which seeks to reduce the probability of groundwater contamination in Jacó.