Hazard assessment of groundwater contamination by point sources in the cities of Vale do Taquari - RS

Abstract

Assessing the risk of aquifer contamination is an important tool for groundwater quality protection and management for the allocation of new business, the installation of wells and the delimitation of areas of greatest danger. The Vale do Taquari region has 432 wells pumped and equipped, extracting water mainly for domestic and animal supplies. Therefore, it is essential to map the danger of groundwater contamination, which comprises the overlap of two maps, the natural vulnerability of the aquifer, obtained by the DRASTIC method, and the potential sources of contamination, classified according to the POSH method. The results show that the largest representation in the vulnerability map is moderate, with 79%, followed by reduced, 16%, and high 5%. The multiplication between the maps showed that the moderate hazard classification corresponds to 46% of the analyzed area, followed by reduced with 38%, negligible with 10% and finally 6% with high index, concentrated in the city of Estrela. In addition it was found that 56 wells are in the analyzed areas. This work is expected to be important for municipalities in order to preserve areas of high vulnerability, as well as to alert areas with a high risk of contamination. And that serves as motivation for the detailed mapping of indices, soils and geology of the Vale do Taquari region.