Avaliação da interface água doce - salgada e permeabilidade do aquífero próximo ao estuário dos bons sinais através da granulometria de sedimentos

Abstract

In aquifers, the assessment of the freshwater interface – assumes an important role in the management and sustainable use of groundwater in coastal areas, as it establishes the depth at which saltwater interacts with freshwater. Monitoring this depth has been used in the diagnosis of saline intrusion. The transmission of salt water from the estuary to the aquifer is controlled by the permeability of the aquifer, which in turn depends on the granulometry of the sediments that make up the aquifer. The coastal aquifer near the estuary is dominated by fine sand sediments, whose permeability is intermediate or moderate. It also presents different values ​​of vertical and horizontal permeability, being classified as an anisotropic aquifer. The position of the freshwater-saltwater interface of this aquifer shows significant variations in depth according to the tidal variation, the maximum and minimum depths are 85 m and 9m recorded neap and spring tides respectively. A few meters from the estuary the groundwater is brackish, characterized by salinity density that varies from 1007.64kg/m3 to 1007.64kg/m3. At the far point of the estuary the groundwater is fresh with a density that varies from 997.01kg/m3 at 996.93 kg/m 3.