Modelo de distribuição espacial do índice GOD para a Bacia Hidrográfica do Rio Pardo - RS

Abstract

Groundwater is responsible for supporting various aquatic systems, and is closely linked to the planet’s water security, since 97 % of the fresh water available is concentrated underground. Its use is linked to several advantages, both economic and health, but because they are hidden underground, the management, control and consolidation of specific public policies are hampered. In addition, misinformation about their social, environmental and economic importance leaves them vulnerable to contamination and misuse. For this reason, in order to increase knowledge about the quality of this resource, several researchers propose methodologies that allow assessing how vulnerable these waters are to contamination. One of these methodologies has a specific purpose to the Brazilian reality and is known as GOD methodology. However, for its application to be carried out on representative maps, it is necessary that estimation techniques are correctly applied. In this context, the objective was to evaluate, through the cross-validation technique, the performance of different models of the GOD index produced by the ordinary Krigagem interpolators, Closest neighbor, Inverse of the squared distance and minimum curvature. The study was carried out in the Rio Pardo River Basin - RS, through the analysis of 143 tubular wells distributed throughout the area. And it revealed that the extreme vulnerability class was not identified in any well, that 16.1 % of them are classified as insignificant vulnerability; 21.7 % as an average vulnerability; 30.8 % low vulnerability and 31.5 % as high vulnerability. For data interpolation, the study demonstrated that ordinary Kriging was the most accurate and accurate interpolator. The spatial distribution model generated, pointed out that the vulnerability to the contamination of groundwater in the basin is well distributed between the northern and southern regions. The lower and lower classes are concentrated in the northern region, and the middle and upper classes in the southern region.