Understanding connected surface-water/groundwater systems using Fourier analysis of daily and sub-daily head fluctuations

Research output: Contribution to journalArticle

Authors

  • R. I. Acworth
  • Gabriel C. Rau
  • Andrew M. McCallum
  • Martin S. Andersen
  • Mark Cuthbert

Colleges, School and Institutes

External organisations

  • University of New South Wales (UNSW) Australia
  • School of Civil and Environmental Engineering, Rensselaer Polytechnic Institute
  • Affiliated with the Connected Waters Initiative Research Centre UNSW Australia Manly Vale
  • Connected Waters Initiative Research Centre (CWI)
  • UNSW Australia

Abstract

The long-term monitoring records of hydraulic heads frequently contain fluctuations originating from different cyclic drivers. Fourier analysis applied to these records can reveal connected surface-water/groundwater system characteristics. The various components of the atmospheric tides, the earth tides and the presence of diurnal responses to evapotranspiration are identified and isolated through band-pass filtering of data recorded from both vented and absolute gauge transducers. The signature of the different cyclic drivers is contained in amplitude and phase of the various signal components and can be used to determine the degree of system confinement. A methodology is described for the calculation of barometric efficiency in confined aquifers based upon the amplitude of the M2 and S2 components of the earth and atmospheric tides. It is demonstrated that Fourier analysis of water-level fluctuations is a simple but underused tool that can help to characterise shallow groundwater systems.

Details

Original languageEnglish
Pages (from-to)143-159
Number of pages17
JournalHydrogeology Journal
Volume23
Issue number1
Early online date5 Sep 2014
Publication statusPublished - Feb 2015

Keywords

  • Analytical solutions, Australia, Confining units, Groundwater hydraulics, Groundwater/surface-water relations