An objective frequency domain method for quantifying confined aquifer compressible storage using Earth and atmospheric tides

• Published in: Geophysical research letters Vol. 43; no. 22; pp. 11,671 - 11,678
• Main Authors: Acworth, R. Ian, Halloran, Landon J. S., Rau, Gabriel C., Cuthbert, Mark O., Bernardi, Tony L.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28-11-2016
• Subjects: Aquifer storage; Aquifer testing; Aquifers; Atmospheric pressure; Atmospheric tides; Barometric efficiency; Barometric pressure; Compounding; Compressibility; Computational fluid dynamics; Computing time; Confined aquifers; Cycles; Duration; Earth; Earth atmosphere; Earth tides; Efficiency; Fluid flow; formation compressibility; Geodetics; Geophysics; Groundwater; groundwater storage; Hydraulics; Interference; Land subsidence; Methods; Piezometric head; Pressure head; Pumping; Pumping tests; Resource evaluation; specific storage; Subsidence; Tests; Tides; Water resources
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL071328

The groundwater hydraulic head response to the worldwide and ubiquitous atmospheric tide at 2 cycles per day (cpd) is a direct function of confined aquifer compressible storage. The ratio of the responses of hydraulic head to the atmospheric pressure change is a measure of aquifer barometric efficiency, from which formation compressibility and aquifer specific storage can be determined in situ rather than resorting to laboratory or aquifer pumping tests. The Earth tide also impacts the hydraulic head response at the same frequency, and a method is developed here to quantify and remove this interference. As a result, the barometric efficiency can be routinely calculated from 6‐hourly hydraulic head, atmospheric pressure, and modeled Earth tide records where available for a minimum of 15 days duration. This new approach will be of critical importance in assessing worldwide problems of land subsidence or groundwater resource evaluation that both occur due to groundwater ion.
Key Points
New method to calculate groundwater compressible storage from the response of hydraulic heads to tidal drivers at subdiel frequencies
Comparing three contrasting barometric efficiency results with traditional correlation plots illustrates the superiority of the new method
The new method is simple, accurate, and only uses commonly available measurements of atmospheric pressure and groundwater head