Determination of the hydraulic conductivity of the Rio Claro Formation:Comparative analysis through grain size analyses and guelph permeameter and slug tests

Abstract

Groundwater in the county of Rio Claro is predominantly extracted from low productivity wells of the Itararé Aquifer, pumping from depths greater than 150 m. These factors in conjunction with increasing demand for water supply have stimulated many industries to exploit Rio Claro Aquifer, constituted by Cenozoic sediments of the Rio Claro Formation, where hydraulic properties are poorly known. The objective of the present study is to evaluate hydraulic conductivity utilizing three monitoring wells located at the UNESP-Campus Rio Claro. In the saturated zone, hydraulic conductivities were determined by Hazen and Shepherd methods, based on grain size analyses, Guelph permeameter and slug tests. Slug tests were interpreted using formulations of Hvorslev (1951) and Bouwer and Rice (1976). Hydraulic conductivities values determined from these methods range from 10-2 to 10-4 cm/s, conferring excellent permo-porosity to the Rio Claro Aquifer.