Water Quality of the Victoria River Basin in the Pailas Geothermal Field, Guanacaste, Costa Rica (2007-2008)

Abstract

Water quality of the Victoria River basin, located in the Pailas Geothermal Field, Guanacaste, Costa Rica, was evaluated during the dry, rainy and dry-rainy seasons of 2007-2008. A total of 15 sites, from the spring to the drinking water extraction area Curubande were, sampled and analyzed for their bacteriological and physicochemical characterization, which can be used as a baseline for monitoring the environmental impact of geothermal fluids on surface water in the basin. Point and non-point sources of contamination were identified and related to water quality parameters and indices. Water of the Victoria River was found to be adequate for drinking after treatment and disinfection. Statistical analysis of the data showed significant differences in color, turbidity, silica, fecal coliforms and Escherichia coli during the three sampling periods. The major effect on the water quality was runoff from pasture areas and soil discharges, which were provoked by erosion and the slope of the river banks. A co-management action plan was elaborated in conjunction with local communities and government authorities according to the results generated in this research. The plan is made up from four components, which include activities addressed towards the main problems of the basin; it was delivered to the local stakeholders concerned with water resources and environmental management.