Determinação da condutividade hidráulica no no aquífero aluvial do Rio Sucuru através do ensaio slug test

Abstract

This work aims to determine the hydraulic conductivity of the alluvial aquifer in a stretch of the Sucuru River basin through the slug test. The alluvial aquifers are geological formations composed of sediments of various grain sizes such as silt, clay, sand and gravel deposited by water currents in the beds and banks of rivers and streams. They form unconfined aquifers of small dimensions and in the case of the Brazilian semiarid region, in the vast majority, limited by crystalline rocks on your base. The tests were carried out at three monitoring piezometers, PZ2, PZ3 and PZ4. The slug test consists of the immersion of a cylindrical bucket, with the subsequent observation of the variation of water level during your retreat, methodology known as bail test or risinghead test. Representative points were chosen for the determination of hydraulic conductivity selecting the piezometers of bigger diameter, and which has the necessary information. Theoretical methods of Hvorslev (1951) and Bouwer & Rice (1976) were used for determining the average hydraulic conductivity. Hydraulic conductivity values were determined based on the mean values of three tests performed on each piezometer. Highmagnitude values were obtained for the Hydraulic Conductivity, in the range of 104 to 105 10 m/s. The results of the assays using the two methods were similar, having the same order of magnitude. These can be understood as hydraulic conductivities of the filter sections, that is, they represent the average hydraulic conductivity of the layers in which the filter is located.