OPTIMISING SUSTAINABLE USE OF GROUNDWATER : A Challenge for Science and Water Markets

1. OPTIMISING SUSTAINABLE USE OF GROUNDWATER:A Challenge for Science and Water Markets John Brumley & Tamara Boyd School of Civil and Chemical Engineering RMIT University

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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)

9. 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

10. 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