Emborê Aquifer hydrodynamic parameter estimation in Farol de São Tomé, Rio de Janeiro State, Brazil, using ocean tidal and piezometric oscillations

Abstract

Obtaining and interpreting physical and chemical parameters of groundwater bodies is vital and an important step for aquifer conceptualization, but knowledge of these parameters is still, in most cases, incipient. The Emborê aquifer, located in the northern Fluminense region, is an important reservoir in the state of Rio de Janeiro, Brazil, and the local population relies on it for domestic water supply. Knowledge of the aquifer is of great importance in the regional context. This work was based on the installation of a multi-parameter sensor in monitoring well ‘UFRJ 05’, which operated over eight months to gather temperature, electric conductivity head data. The well drains the Emborê Aquifer, a water body with a confined nature. Results of  temperature and conductivity measurements from the multiparameter probe did not show significant variations in salinity and temperature throughout the period. Regarding hydraulic head variation, it was directly linked to the variation in ocean tide cycles. Therefore, a methodology was applied to estimate aquifer hydraulic diffusivity relative to the tide. The comparison of resulting data with the hydraulic diffusivity from a pumping test carried out in UFRJ 05 well, allowed evaluation of advantages and disadvantages of acquiring aquifer parameters by each method.