Experimental observations of watertable waves in an unconfined aquifer with a sloping boundary

No Thumbnail Available
File version
Author(s)
Cartwright, N
Nielsen, P
Li, L
Griffith University Author(s)
Primary Supervisor
Other Supervisors
Editor(s)
Date
2004
Size
File type(s)
Location
License
Abstract

Observations of horizontal and vertical variations in piezometric head in a homogeneous, laboratory aquifer are presented and discussed. The observed fluctuations are induced by a simple harmonic oscillation in the clear water reservoir acting across a sloping boundary. The data qualitatively supports existing theories in that higher harmonics are generated in the active forcing zone and that a significant increase in the inland, asymptotic watertable over height (relative to that found for the vertical boundary case) is observed. The observed overheight is shown to be accurately reproduced by existing small-amplitude perturbation theory. Detailed measurements in the vicinity of the sloping boundary reveal that the signal of generated higher harmonics is strongest near the sand surface and that vertical flows are significant in this region. The aquifer is of finite-depth and is influenced by capillary effects, the experimental data therefore exposes limitations of theories which are based on the assumption of a shallow aquifer free of capillary effects. The dispersive properties of the measured pressure wave in the aquifer are comparable to those found from field observations and likewise do not agree with those predicted by the capillary free, shallow aquifer theory. Although some improvement is obtained, discrepancies between the data and theory persist even when a finite-depth aquifer and capillary effects are considered in the theoretical model. Further sand column experiments eliminate a truncated capillary fringe as a possible contributor to these discrepancies. However, the neglect of horizontal flows in the fringe may have caused the discrepancies.

Journal Title

Advances in Water Resources

Conference Title
Book Title
Edition
Volume

27

Issue

10

Thesis Type
Degree Program
School
Publisher link
Patent number
Funder(s)
Grant identifier(s)
Rights Statement
Rights Statement
Item Access Status
Note
Access the data
Related item(s)
Subject

Applied mathematics

Civil engineering

Environmental engineering

Persistent link to this record
Citation
Collections