Integrated evaluation of surficial and ground water resources within Boqueirão river Basin, west of Touros, RN

Abstract

Boqueirão watershed is situated in the transition zone between the Coastal Basin, where the climate is humid, and, the Potiguar Basin, semi-arid region, Rio Grande do Norte State, covering 190 km2. The Barreiras aquifer and the Boqueirão Lake are the sources that supply the communities and irrigate part of that area. This work evaluates the possibilities of increasing the water provision to the local development and to supplying communities in the semi-arid region placed up to 70 km from the Boqueirão, where there is a shortage of water. An annual exploitable volume of water of about 17.8 million m³ was estimated. The groundwater on the East sector of the Boqueirão Lake has a very low salinity average, and Na⁺-Cl^- is the water type that predominates. On the other sectors, the salinity of water varies from medium to high and are Ca²⁺-Mg²⁺-Cl^- -HCO₃^- water type. In this case, it is likely that the limestone rocks underlying the Barreiras Aquifer affect the waters. The salinity of the surface waters varies from low to medium and are Na⁺-Ca²⁺-Mg²⁺-Cl^--HCO₃^-, which might indicate a mixture of waters from the Barreiras Aquifer sandstone and the carbonate rocks.