Smoothing of Slug Tests for Laboratory Scale Aquifer Assessment—A Comparison among Different Porous Media

Aristodemo Aristodemo,Lauria Lauria,Tripepi Tripepi,Rivera-Velasquéz Rivera-Velasquéz

doi:10.3390/w11081569

Abstract

A filtering analysis of hydraulic head data deduced from slug tests injected in a confined aquifer with different porous media is proposed. Experimental laboratory tests were conducted in a large-scale physical model developed at the University of Calabria. The hydraulic head data were deduced from the records of a pressure sensor arranged in the injection well and subjected to a processing operation to filter the high-frequency noise. The involved smoothing techniques are the Fourier transform and two types of wavelet transform. The performances of the filtered hydraulic heads were examined for different slug volumes and four model layouts in terms of optimal fitting of the Cooper’s analytical solution. The hydraulic head variations in the confined aquifer were analyzed using wavelet transform in order to discover their energy contributions and frequency oscillations. Finally, the raw and smoothed hydraulic heads were adopted to calculate the hydraulic conductivity of the aquifer.

Highlights

The slug tests can be considered the most currently used field tests for the estimation of hydrodynamic parameters characterizing an aquifer. These tests are often preferred to traditional pumping tests due to the ease of execution, low costs, in investigations of contaminated aquifers, and for the reduced volume of porous medium involved in the measurements, pumping tests are generally considered more reliable and less subject to errors and uncertainties [1,2,3,4,5,6,7]
Afterwards, the raw values of h were filtered by Fourier transform (FT) and two wavelet transforms (WTs), i.e., Mexican t2 (t) = π−1/4 (10)
An experimental investigation at laboratory scale executed on a 3D physical model was carried out toAn study the hydraulic responseatoflaboratory an aquiferscale by means of slug

Summary

Introduction

The slug tests can be considered the most currently used field tests for the estimation of hydrodynamic parameters characterizing an aquifer. These tests are often preferred to traditional pumping tests due to the ease of execution, low costs, in investigations of contaminated aquifers, and for the reduced volume of porous medium involved in the measurements, pumping tests are generally considered more reliable and less subject to errors and uncertainties [1,2,3,4,5,6,7]. Numerous topics linked to the slug tests were widely analyzed and investigated. Further investigations are still possible on some aspects related to slug tests, such as the management of wide data sets

Objectives

Methods

Results

Conclusion