Groundwater quality assessment using index methods and multivariate statistical analysis: River Pavas basin (Colombia)

Abstract

The Pavas river valley basin is an agricultural and livestock region, located in the municipality of La Cumbre, in the Valle del Cauca department of Colombia. The inhabitants are supplied by piped water, which in times of water deficit may present limitations in terms of quantity and quality, and this has led to a transition towards the exploitation and use of groundwater resources. This study used the physicochemical and microbiological analysis of groundwater samples taken within the research area during two different hydrometeorological periods (rainy and dry seasons). Statistical analysis methods (analysis of normality, homoscedasticity, and the difference between populations) and multivariate (principal component and hierarchical cluster analysis) were applied to interpret groundwater hydrogeochemistry. Additionally, water quality was evaluated using the water quality indexes methods for domestic use and human consumption and for irrigation. No evidence of an effect of hydrometeorological periods on groundwater hydrogeochemical behavior was identified. Additionally, the existence of natural factors (weathering and dissolution of rocks) and anthropic factors (interaction with discharges of agricultural or domestic origin) that alter the hydrogeochemistry of groundwater was established. Lastly, according to the water quality indices, the groundwater samples analyzed were placed in the category «unviable for direct consumption» by humans and «without or with low restrictions» for use of water for irrigation.