TY - JOUR
T1 - Estimating hydraulic properties from tidal propagation in circular islands
AU - Solórzano-Rivas, S. C.
AU - Werner, A. D.
AU - Irvine, D. J.
N1 - Funding Information:
S. Cristina Solórzano-Rivas is supported by a Research Training Program scholarship. Adrian Werner is the recipient of an Australian Research Council Future Fellowship (project number FT150100403). We would like to thank Neville Robinson for his suggestions after reading the manuscript and Kenneth Pope for the discussions about different possible analysis techniques for this research. Our gratitude to Vincent Post for his kind assistance with the PBC package. We also gratefully acknowledge the suggestions of two anonymous reviewers.
Publisher Copyright:
© 2021 Elsevier B.V.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/7
Y1 - 2021/7
N2 - Observations of tidal propagation in coastal aquifers allow for rapid, low-cost quantification of aquifer parameters that are integrated over significant distances. Previous methods for aquifer property estimation from tidal propagation have focussed on continental aquifers and assumed straight, infinite shorelines. A recent investigation has proposed a correction to the Ferris analytical solution for straight shorelines (‘Ferris solution’) to be applied under radial flow conditions. In this paper, an existing analytical solution as a function of radial flow conditions (‘circular solution’) and the corrected Ferris solution are applied for the first time to obtain aquifer diffusivity in orbiculate-shaped islands. Inversion of the circular solution (to obtain diffusivity) requires iterative methods, which are applied to synthetic island aquifers with known diffusivity values ranging between 150,000 m2/d and 500,000 m2/d. The circular solution was tested for both confined and unconfined conditions and for tidal periods ranging from around 8 to 24 hours. Known aquifer diffusivity values were reproduced within 2.5% of known values, even where randomised noise was added to synthetic groundwater tidal signals, and for both confined and unconfined aquifer conditions. Application of the corrected Ferris solution was found to be reliable for both confined and unconfined conditions, with discrepancies in aquifer diffusivity < 1% and < 2.5%, respectively, including with noise added to the groundwater tidal signals. The methodology presented in this work to estimate aquifer diffusivity in orbiculate-shaped islands is an improvement over classic approaches (e.g., the Ferris solution). In particular, the radial-flow correction to the Ferris solution provides for simple calculations of aquifer diffusivity of similar accuracy to the more complex radial analytical solution.
AB - Observations of tidal propagation in coastal aquifers allow for rapid, low-cost quantification of aquifer parameters that are integrated over significant distances. Previous methods for aquifer property estimation from tidal propagation have focussed on continental aquifers and assumed straight, infinite shorelines. A recent investigation has proposed a correction to the Ferris analytical solution for straight shorelines (‘Ferris solution’) to be applied under radial flow conditions. In this paper, an existing analytical solution as a function of radial flow conditions (‘circular solution’) and the corrected Ferris solution are applied for the first time to obtain aquifer diffusivity in orbiculate-shaped islands. Inversion of the circular solution (to obtain diffusivity) requires iterative methods, which are applied to synthetic island aquifers with known diffusivity values ranging between 150,000 m2/d and 500,000 m2/d. The circular solution was tested for both confined and unconfined conditions and for tidal periods ranging from around 8 to 24 hours. Known aquifer diffusivity values were reproduced within 2.5% of known values, even where randomised noise was added to synthetic groundwater tidal signals, and for both confined and unconfined aquifer conditions. Application of the corrected Ferris solution was found to be reliable for both confined and unconfined conditions, with discrepancies in aquifer diffusivity < 1% and < 2.5%, respectively, including with noise added to the groundwater tidal signals. The methodology presented in this work to estimate aquifer diffusivity in orbiculate-shaped islands is an improvement over classic approaches (e.g., the Ferris solution). In particular, the radial-flow correction to the Ferris solution provides for simple calculations of aquifer diffusivity of similar accuracy to the more complex radial analytical solution.
KW - Coastal aquifer
KW - Tidal propagation
KW - Parameter estimation
KW - Circular islands
KW - Radial groundwater flow
KW - Ferris solution
UR - http://www.scopus.com/inward/record.url?scp=85105549572&partnerID=8YFLogxK
U2 - 10.1016/j.jhydrol.2021.126182
DO - 10.1016/j.jhydrol.2021.126182
M3 - Article
AN - SCOPUS:85105549572
VL - 598
SP - 1
EP - 14
JO - Journal of Hydrology
JF - Journal of Hydrology
SN - 0022-1694
M1 - 126182
ER -