Comparing Methods of Barometric Efficiency Characterization for Specific Storage Estimation.

Area of Science:

• Hydrogeology
• Geophysics

Background:

• Groundwater responses to barometric pressure fluctuations are key indicators of aquifer properties.
• Barometric efficiency (BE) is a concept used to characterize these responses.
• BE values offer efficient, low-cost estimates of specific storage in semiconfined and confined aquifers.

Purpose of the Study:

• To compare eight existing methods for estimating barometric efficiency (BE).
• To evaluate the effectiveness of different methods in estimating aquifer confinement status and BE.
• To assess the utility of these methods as low-cost alternatives to hydraulic testing.

Main Methods:

• Utilized data from the Peel region, Western Australia.
• Employed Fourier analysis and regression deconvolution to determine aquifer confinement.
• Applied frequency and time domain methods for BE estimation, including the Acworth et al. (2016) method.

Main Results:

• Fourier analysis proved robust for quantifying spatial variations in aquifer confinement.
• Most BE estimation methods were affected by diurnal/semidiurnal signals, except for the Acworth et al. (2016) method.
• Specific storage values derived from BE were consistent with historical pumping test results.

Conclusions:

• The studied methods provide efficient, low-cost alternatives for estimating aquifer confinement, BE, and specific storage.
• Minimal observation frequency and duration are required, potentially leveraging existing groundwater hydrograph data.
• These methods offer valuable insights into semiconfined and confined aquifer characteristics.