Effects of vadose zone on groundwater table fluctuations in unconfined aquifers

Kong, Jun, Xin, Pei, Hua, Guo-Fen, Luo, Zhao-Yang, Shen, Cheng-Ji, Chen, Dan and Li, Ling (2015) Effects of vadose zone on groundwater table fluctuations in unconfined aquifers. Journal of Hydrology, 528 397-407. doi:10.1016/j.jhydrol.2015.06.045


Author Kong, Jun
Xin, Pei
Hua, Guo-Fen
Luo, Zhao-Yang
Shen, Cheng-Ji
Chen, Dan
Li, Ling
Title Effects of vadose zone on groundwater table fluctuations in unconfined aquifers
Journal name Journal of Hydrology   Check publisher's open access policy
ISSN 0022-1694
Publication date 2015-09-01
Sub-type Article (original research)
DOI 10.1016/j.jhydrol.2015.06.045
Open Access Status Not yet assessed
Volume 528
Start page 397
End page 407
Total pages 11
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2016
Language eng
Formatted abstract
Above a shallow unconfined aquifer, a considerable amount of water is stored in the vadose zone. Through water exchange with the underlying unconfined aquifer, the vadose zone affects the groundwater table dynamics and overall behavior of the aquifer. In this paper, we examine tide-induced groundwater table fluctuations in unconfined aquifers influenced by vadose zone of finite thickness. Under the condition of small aquifer thickness (D) compared with the groundwater wavelength (L) (i.e., μ2=(D/L)2≪1) and small boundary oscillation amplitude (a) (i.e., ε=a/D≪1) (where μ2 and ε are two parameters), an approximate analytical solution was derived to quantify systematically the vadose zone effects, with a particular consideration of capping by the ground surface, i.e., the upper boundary of the vadose zone. Depending on the extent to which the capillary rise is truncated by the ground surface, the vadose zone enhances the groundwater table fluctuations in an unconfined aquifer. However, the mean groundwater table height and exchange between surface water and groundwater are reduced due to the presence of the vadose zone. These effects are intensified with increased capillary rise, but weakened as the vadose zone thickens. This study provides a criterion for assessing the importance of vadose zone in modulating the response of unconfined aquifers to low-frequency forcing oscillations such as tides.
Keyword Analytical solution
Boussinesq equation
Capillary fringe
Groundwater fluctuation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
Official 2016 Collection
 
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