Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations

Cuthbert, M. O., Acworth, R. I., Andersen, M. S., Larsen, J. R., McCallum, A. M., Rau, G. C. and Tellam, J. H. (2016) Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations. Water Resources Research, 52 2: 827-840. doi:10.1002/2015WR017503


Author Cuthbert, M. O.
Acworth, R. I.
Andersen, M. S.
Larsen, J. R.
McCallum, A. M.
Rau, G. C.
Tellam, J. H.
Title Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations
Journal name Water Resources Research   Check publisher's open access policy
ISSN 1944-7973
0043-1397
Publication date 2016-02-11
Year available 2016
Sub-type Article (original research)
DOI 10.1002/2015WR017503
Open Access Status Not Open Access
Volume 52
Issue 2
Start page 827
End page 840
Total pages 14
Place of publication Hoboken, NJ, United States
Publisher Wiley-Blackwell Publishing
Collection year 2017
Language eng
Abstract Understanding and managing groundwater resources in drylands is a challenging task, but one that is globally important. The dominant process for dryland groundwater recharge is thought to be as focused, indirect recharge from ephemeral stream losses. However, there is a global paucity of data for understanding and quantifying this process and transferable techniques for quantifying groundwater recharge in such contexts are lacking. Here we develop a generalized conceptual model for understanding water table and groundwater head fluctuations due to recharge from episodic events within ephemeral streams. By accounting for the recession characteristics of a groundwater hydrograph, we present a simple but powerful new water table fluctuation approach to quantify focused, indirect recharge over both long term and event time scales. The technique is demonstrated using a new, and globally unparalleled, set of groundwater observations from an ephemeral stream catchment located in NSW, Australia. We find that, following episodic streamflow events down a predominantly dry channel system, groundwater head fluctuations are controlled by pressure redistribution operating at three time scales from vertical flow (days to weeks), transverse flow perpendicular to the stream (weeks to months), and longitudinal flow parallel to the stream (years to decades). In relative terms, indirect recharge decreases almost linearly away from the mountain front, both in discrete monitored events as well as in the long-term average. In absolute terms, the estimated indirect recharge varies from 80 to 30 mm/a with the main uncertainty in these values stemming from uncertainty in the catchment-scale hydraulic properties.
Keyword Water table fluctuation
Indirect recharge
Mountain front
Ephemeral stream
Dryland hydrology
Focused recharge
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Geography, Planning and Environmental Management Publications
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