Assessment of the vulnerability to contamination of fractured aquifers based on DRASTIC method

Abstract

Vulnerability map is an effective tool to assess and identify the areas that are most susceptible to groundwater contamination, and can aid in the planning and management of municipal groundwater. These maps can help decision-making regarding land use and cover, pointing out proper sites to rural and/or urban sprawling but also highlighting restrictions for groundwater withdrawal. This paper aims at evaluating the influence of the lineament density (DRASTIC-LD) and the influence of the land use and cover, along with the lineament density, (DRASTIC-LDLU) in the classification of the vulnerability of the Serra Geral Aquifer System. The DRASTIC approach was modified by adding the lineament density. The DRASTIC-LD method showed high (70.73%), moderate (17.04%) and very high (12.17%) vulnerability. The DRASTIC-LDLU method presented high (55.35%), extreme (19.65%), very high (14.66%) and moderate (10.31%) vulnerability. Lineament density and land use and cover had a significant influence on the vulnerability classification. The spatial distribution of vulnerable zones was quite similar to those obtained by applying the original DRASTIC model. However, a significant increase in vulnerability was observed across the study area when the lineament density parameter was added, followed by an even greater vulnerability when the lineaments were inserted together with land use land cover. Inserting these two parameters together provides a more accurate result of vulnerability in fractured aquifers, as it is a more faithful representation of the reality of this system.