ANÁLISE DA VULNERABILIDADE NATURAL À CONTAMINAÇÃO DA ÁGUA SUBTERRÂNEA: COMPARATIVO ENTRE A METODOLOGIA GOD E DRASTIC

Water is an essential natural resource to all forms of life; however, antropic activity, population increase and urbanization are changing the quality of shallow springs and making them unavailable for certain uses. Groundwater emerges as alternative to complete or even replace surface water; however, it is essential to have control over antropic activities so they would not contaminate aquifers. Thus, the aim of the present study is to compare the DRASTIC and GOD methods applied to the Vacacai-Mirim River basin, in Rio Grande do Sul State. Both methods recorded vulnerability classes between insignificant an external, with higher prevalence of moderate (DRASTIC) and high (GOD) vulnerability. The GOD method held 89.91% of the vulnerability in 2 classes (moderate and high), whereas the DRASTIC one recorded 66.15% in these same classes. The DRASTIC method presented the highest class vulnerabilities in the study site. This outcome regards more consistent results and similar to parameters recorded in the field. Nevertheless, GOD is simpler due to the number of variables necessary for its application. It is important highlighting the importance of applying these methodologies to provide subsidies for decision-making by water resource managers.