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This article explores the challenges in optimising sustainable groundwater use, emphasizing the need for science-based management and effective water market mechanisms. It discusses historical perspectives, Australian water reforms, groundwater management plans, and the importance of sustainable yield. Issues such as overallocation, consequences of excessive withdrawal, and impediments in groundwater markets are highlighted. The conclusion stresses the potential benefits of trading groundwater but underscores the necessity to balance economic gains with environmental considerations. Key tasks for improvement include community education, data management, and environmental allocation understanding.
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OPTIMISING SUSTAINABLE USE OF GROUNDWATER:A Challenge for Science and Water Markets John Brumley & Tamara Boyd School of Civil and Chemical Engineering RMIT University
Introduction • Sustainable groundwater management rare prior to 1980s • Aquifer over-development eventually seen as a threat • Poor understanding of aquifers cannot stop us from action • Trading can enhance management of groundwater • Surface water trading has dominated reforms to date • This must change
Drivers of Australian Water Reform • Growing water deficit • Enhanced allocation of current resources needed • Deregulation of the water industry • Focus shifted from resource development to management • Brundtland Report, Agenda 21, National Strategy for ESD • CoAG’s 1994 Water Reform Framework
CoAG Water Reform • National policy for reform of rural and urban water industries • Explicitly linking fiscal and environmental objectives • Jurisdictional differences in implementation • Water pricing based on full cost recovery • Comprehensive water allocations, separated from land • Allocations for the environment and water trading
Ensuing Groundwater Program • ARMCANZ groundwater policy discussion paper • Objective: sustainable use of the resource • Better integration of surface and groundwater • Development of groundwater management plans • Groundwater arrangements not subject to assessment payments • Yet consistent, coordinated action must prevail
Sustainable Yield • Total allocations should not exceed sustainable yield: the groundwater extraction regime, measured over a specified planning time frame, that allows acceptable levels of impact and protects the higher value uses that have a dependency on the water • Conceptually difficult to implement • Methodology varies greatly between and within countries • Aquifer characteristics or ‘default’ % of recharge
Issues • Limiting extraction to recharge doesn’t control externalitites • Interference & environmental degradation • Groundwater mining may be policy • Las Vegas Valley, SA/Vic Border, Latrobe Valley • Intentional overallocation acceptable only when: • Publicly accepted strategic benefit • Resource is efficiently used and tightly managed • Resource may be overallocated but underused
Consequences of Excessive Withdrawal Reversible Interference: • Pumping lifts/costs increase • Well yields decrease • Springflow/baseflow reduction • Effect on phreatophytic vegetation Irreversible Deterioration: • Saline water intrusion/upconing • Ingress of polluted waters • Aquifer compaction/yield reduction • Land subsidence (Foster, 1999)
Australia’s Groundwater Markets • Impediments include: • Deficiency in reliable data • Less portable nature of groundwater • Potential impacts from groundwater transfers • Few embargoed areas, consequently ‘thin’ markets • Activation of dormant licences • Use of zoning to control transfers
Conclusion • Trade can optimise economic benefits of groundwater use • Hydrogeological and environmental checks must be met • Groundwater must keep pace with surface water reform • Considerable work to be done, including: • Community/user education • Data attainment & interpretation • Understanding environmental allocations
