Karst aquifer vulnerability assessment using the COP and EPIK methods in central Brazil

Abstract Karst aquifers are highly susceptible to contamination and the application of methodologies that identify these critical areas is an excellent strategy for promoting their conservation. With this in mind, this study aims to assess the applicability of two aquifer vulnerability classification methods, COP and EPIK, in the Terra Ronca State Park (PETeR) and Serra Geral APA conservation units, located in Central Brazil. The chosen methods assess the physical conditions of the environment (relief, lithology, soils, karst features, vegetation) to determine the areas naturally vulnerable to contamination. The analyses were carried out in a GIS environment. The results for the COP method showed a predominance of areas with low (43.08%) to very low (33.72%) vulnerability, followed by moderate (16.20%), high (5.25%) and very high (1.81%) vulnerability. As for the EPIK method classification, the high (44.52%) and moderate (41.92%) classes predominated, while the other classes, very high and low, accounted for 4.68% and 8.88% respectively. It is important to note that the differences in the proportions of areas in each class in the methods applied can be attributed to the varying weights assigned to the parameters used and the differences in the classification categories. Despite the differences, both methods identified areas with very high vulnerability in the central part of the study area, precisely where karst features such as caves and dolines are concentrated. This highlights the importance of identifying the most vulnerable areas in a karst environment in order to ensure sustainable management of its natural resources.