The potential of the barreiras aquifer in the lower course of the Doce River, Rio Grande do Norte state, northeast Brazil - Integration of hydrogeological and geophysical data

Abstract

The present article is a synthesis of studies developed by the Fundação Norte-Rio-Grandense de Pesquisa e Cultura-FUNPEC and Universidade Federal do Rio Grande do Norte-UFRN for the Companhia de Águas e Esgotos do Rio Grande do Norte-CAERN, in the lower course of Doce River, RN. This paper also presents alternatives to increase the water supply from wells in the Barreiras Aquifer located to the north of Natal district, RN, considering the degraded water quality due to nitrate contamination from the right margin of Doce River. The methodology was based on the combined use of hydrogeological and geophysical techniques (gravity and electrical resistivity). The regional structure was previously characterized by morphotectonic analysis and gravimetric and geoelectric data interpretation. According to these data, two preferential fault directions (NW and NE) directly influence local geometry of the aquifer causing abrupt variations of the saturated thickness. The potential of the Barreiras Aquifer increases gradually on the left bank of Doce River from east to west, due to larger spacing between hydrogeological equipotential surface and larger saturated thickness. These observations provided the basis to locate a new water collection area, where new wells are going to be drilled with 300 m3/h estimated total discharge.