Recharge processes at the St George Irrigation Area

Dafny, Elad (2015) Recharge processes at the St George Irrigation Area. In: 2nd Australian Cotton Research Conference 2015: Science Securing Cotton's Future, 8-10 Sept 2015, Toowoomba, Australia.

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Abstract

Since the 1950s, irrigated cropping has taken place in the St George Irrigation Area (SGIA), following clearance of the native vegetation and construction of water canals, carrying river water to the agricultural lands. The change from open-forest to arable lands mostly irrigated involved changes to the groundwater balance and in turn, groundwater quality. Deep-drainage and leaks from the water canals and dams, to name two possible water sources, which carry different amounts of salts into the sub-surface, may affect the groundwater salinity.
The groundwater under the SGIA ranges in quality from fresh water, with about 50 mgCl/L, to salty water, with ~10,000 mgCl/L. We analysed all of the available bore water samples, to detect any on-going salinity trends (rising/stable/falling) and identify potential sources. Results indicate the existence of four end-members, namely, saline formation water, brackish deep-drainage, slightly brackish flood-recharge water, and fresh imported river-water. Each of these has a typical geochemical composition, which allows reconstructing the past and the current recharge processes in the SGIA. The groundwater composition at many bores varied over time, to reflect the changes in the dominant end-member.
This study demonstrates that effective changes in groundwater quality can occur in a relatively short time-frame.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Lecture)
Refereed: No
Item Status: Live Archive
Additional Information: Abstract only published in Proceedings. Copyright 2015 author. This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Date Deposited: 19 Jun 2016 23:40
Last Modified: 10 Jul 2017 03:18
Uncontrolled Keywords: groundwater; St George Irrigation Area; recharge; geochemical evolution
Fields of Research : 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
05 Environmental Sciences > 0502 Environmental Science and Management > 050209 Natural Resource Management
Socio-Economic Objective: D Environment > 96 Environment > 9606 Environmental and Natural Resource Evaluation > 960608 Rural Water Evaluation (incl. Water Quality)
D Environment > 96 Environment > 9611 Physical and Chemical Conditions of Water > 961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use)
Funding Details:
URI: http://eprints.usq.edu.au/id/eprint/27684

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