Sustainability of groundwater supply - Groundwater for the Future Resource optimisation (recharge/discharge, storativity/yield, pumping etc)
Issue: Proper methodology for determining all the parameters necessary for quantifying the sustainable yield and the optimisation of the resource are required.
Groundwater is the main water source of many towns and community centres all over Australia. It is also used for irrigation in several regions. In most areas allocations and/or use is in excess of the sustainable yield. In addition there is no single understanding or definition of sustainable yield across Australia.
Many terms are used to describe the resource potential; optimal yield, safe yield, mining yield and sustainable yield, but in general they are not well defined and in most cases are mainly described by the recharge component. The optimum utilisation of each resource depends upon balancing the recharge and discharge components with minimal disturbance to the other users (including the environment).
Although there are many studies for determining recharge, discharge, storativity and specific yield, the application of these techniques in most cases are not well coordinated towards a sustainable yield concept and optimisation of the resource. At the same time, determining some of the parameters ie-specific yield are not well developed and are guess estimates.
Estimates of recharge have also been the basis for estimates of land salinisation, groundwater salinisation and river salinisation, the groundwater discharge component that is the main cause of salinisation has been grossly overlooked.
Projects and contacts:
- The ongoing water supply schemes for urban and rural water supplies in all states and territories.
- Hydrology of the Howard River Basin, Northern Territory : quantification of the water balance of the basin, and assessment of the ecologically sustainable level of groundwater extraction.
Contact: Dr Peter Cook - Irrigation-induced Groundwater salinisation, SW Murray Basin: prediction of increases in salinity of the groundwater following irrigation development for Olive plantations, south-west Big Desert, near Tintinara, South Australia.
Contact: Dr Fred Leaney - Increasing the sustainable yield of the Gnangara Mound, WA.
Contact: Dr Ramsis Salama - Perth Basin aquifer sustainability (CGS).
Contact: Philip Commander
Water Banking (artificial recharge)
 Issue: CGS research has demonstrated that even saline aquifers can be used to store temporary excesses of surface water to create new water resources or extend the life of over-exploited groundwater.
The conjunctive use of groundwater and surface water provides a flexible approach to water management. With the increased environmental constraints in siting surface reservoirs, conjunctive use for "banking" surplus surface water in aquifers in times of plenty, for use in times of scarcity assumes increasing importance.
A technique called aquifer storage and recovery (ASR) where the same wells are used for injection and recovery to reduce operational problems such as well clogging, now offer viable ways in which water can be stored subsurface in deeper aquifer systems. CGS has demonstrated that brackish or saline aquifers, can be used to create fresh/potable water storages subsurface, where none existed previously.
Using infiltration basins for artificial recharge of shallower unconfined aquifers where land is available provides a more conventional and economic solution and reduces water losses by evaporation. There is a need to establish better techniques for monitoring and predicting water quality and aquifer permeability changes during aquifer storage, Extension from predominantly calcareous or fractured rock aquifers to unconsolidated and siliceous consolidated aquifers is warranted, to assess viability of proposed AR and ASR schemes.
Well-monitored demonstration projects are required in a variety of hydrogeological situations, to better understand hydrogeological and biogeochemical constraints to storing water underground, and to provide a basis for socioeconomic evaluation of such schemes. Projects and contacts: - AWWARF project on Water quality improvements during aquifer storage and recovery.
Contact: Dr Peter Dillon - Artificial recharge of streamwater by infiltration into shallow sand aquifer, Albany WA.
Contact: Len Baddock - Use of shallow groundwater in high water table areas, and/or potable reservoir water to recharge confined aquifers, Jandakot area WA.
Contact: Chengchao xu - See also ASR projects below and under minesite hydrogeology
Aquifer Storage and Recovery (ASR) with Reclaimed Water for Irrigation Reuse  Issue: Sewage effluent and stormwater are being increasingly regarded as a resource which can be used for irrigation in agriculture, or on urban parks and gardens. Aquifer storage of reclaimed water provides a mechanism for storage where irrigation water needs are seasonal. During subsurface storage pathogenic bacteria can be reduced or eliminated.
There are major potential problems with infiltration and injection of reclaimed water, particularly from clogging due to suspended solids and biofilms, and potential impacts on the quality of native groundwater in receiving and adjacent aquifers. The type and level of treatment required is critical to the technical success and acceptability of storing reclaimed water in aquifers. As well as defining an adequate technical basis for storage of reclaimed water, it is essential to consider economic aspects (water pricing), and community attitudes to reuse (eg of reuse (public health concerns, risk management and public acceptance).
Projects and contacts: - Bolivar reclaimed water ASR research project using a brackish confined Tertiary aquifer near Bolivar STP as part of the Virginia pipeline scheme for irrigation reuse of reclaimed water
- Wastewater ASR using confined Tertiary aquifers at Christies beach, SA, for irrigation reuse.
Contact: Russell Martin - Halls Head Pilot Reuse Scheme.
Contact: Dr Simon Toze
Fractured rock aquifers - assessment, development and disposal
Issue: About 40% of groundwater in Australia is stored in fractured rock aquifer, and much of this may be available for beneficial use. However, rates of groundwater movement in these systems is difficult to quantify. Groundwater yield is often extremely variable, and dependent on the distribution of major fractures.
Groundwater recharge is impossible to quantify with existing techniques, and groundwater flow direction can be more related to the orientation of fractures than to the hydraulic head distribution. LWRRDC recently recognised the importance of this area, and deficiencies in current understanding, and funded three projects to develop new methods for investigation in these environments. Using fractured and deep formations as disposal sites for liquid and solid waste is another emerging issue in Australia.
Whilst there is a need to identify and develop better techniques and methodologies for evaluation of water resources in fractured aquifers for beneficial use, waste disposal and waste storage systems require delineation of fractured formations which are not part of a groundwater system, for minimisation of migration of waste constituents. Both issues need to identify flow systems, transport processes, fault/fracture integrity and hydraulic compartments.
The heterogeneous nature of these geological formations makes these assessments very difficult and no generally accepted and there are no reliable methods currently available for this. The use of environmental tracers, field monitoring, novel hydraulic techniques, geophysical surveys and advancement in modelling need to be developed. Projects and contacts: - Groundwater Recharge and Flow Velocities in Fractured Rock Aquifers; Clare Valley, South Australia.
- Assessment of groundwater supplies in fractured basalts; Atherton tablelands, Queensland.
- Influence of fractures on groundwater flow in an urban, saline catchment, Wagga, NSW.
Contact: Dr Peter Cook - Using isotope techniques to determine groundwater sustainability.
Contact: Dr Fred Leaney
Risk / hazard assessment from land-use change
Issue:Changes in land use can have a severe impact on groundwater quality. Poor planning, land use and water management in cities in many parts of the world has polluted town water supplies, has caused saltwater intrusion and land subsidence. In recognition of the need for effective and efficient methods for protecting groundwater resources from future contamination in rural and urban areas, and particularly in irrigation areas overlying unconfined aquifers, integrated groundwater vulnerability assessment techniques need to be developed for predicting which areas are more likely than others to become contaminated or impacted as a result of land use activities and changes at the surface.
Once identified, those areas could then be subjected to certain regulatory restrictions or targeted for greater attention aimed at preventing contamination of the groundwater resource. The risk assessment tool should be coded in a GIS environment, interfaced with flow and transport models, knowledge-based and user-interactive. The user must be able to apply the vulnerability model to assess the risk to groundwater quality with changes in land use.
Projects and contacts: - VulNitrate: Groundwater vulnerability assessment to nitrate pollution from different land uses.
- Vulnerability of the soils of the Gnangara Mound (Western Australia) to nutrients and pesticide leaching
Contact: Dr Ramsis Salama - Review of land use impacts on ground and surface water systems on the Swan Coastal Plain (CGS partners); coupling a groundwater vulnerability model with socio-economic tools.
- Preparation of a book of landuse impacts on groundwater management in urban areas throughout the world, as part of UNESCO project IHP 3.4.
Contact: Dr Steve Appleyard - Land-use impacts in the Ord-Bonaparte region.
Contact: Dr Tom Hatton
Minesite hydrogeology (groundwater supplies, dewatering, final voids)
Issue: Minesites are often highly complex hydrogeologically, with multiple aquifer units, stratigraphic discontinuities and irregular patterns of fractures and faults. There is a need for an improved foundation of knowledge on which to base management and rehabilitation decisions affecting the environmental impact of mining on surface water and groundwater resources, from use of water in mineral processing activities, and from dewatering.
Industry is also interested in projects that address the problems of predicting and managing final void water quality. Two examples of current projects in WA highlight the need for better understanding of groundwater sustainability for mine viability. The hypersaline groundwater resources of the Eastern Goldfields are crucial to the processing of the gold and nickel ore resources of the region.
These groundwater resources are being steadily depleted at the present rate of pumping and use by industry for mineral process water. Therefore assessment and investigation of alternative sources of process water for industry are urgently needed for the long-term supply. Large portions of the economic mineral reserves mine sites in the Pilbara region are below the groundwater table and a significant dewatering effort is anticipated to access and mine the ore.
Aquifer storage and recovery techniques that allow excess groundwater to be stored for later use could provide further benefit by offsetting future mine-site water. Additionally, a variety of minesites are located in areas where water tables are close to the surface, often adjacent to vulnerable surface water resources such as wetlands. There is a need to assess the impacts on both groundwater quality and quantity, as well as determine the dynamic impacts on nearby surface water resources.
Projects and contacts: - Groundwater/lakewater interaction, Jangardup South mineral sands mining (Cable Sands Pty Ltd)
- Hydrology of Lake Lefroy (WMC)
- Groundwater contamination and cleanup, WMC Baldivis tailings (WMC)
- Artificial groundwater recharge studies, Kalgoorlie (AMIRA and industry partners)
- Nammuldi (Pilbara) aquifer recharge trial (Hammersley Iron)
- Collie basin - Groundwater dating and impacts of mine dewatering on groundwater resources (CGS partners/ Collie basin Research Steering Committee).
- Final mining-void water quality (through ACMER)
Contact: Dr Jeffrey Turner
Social Planning and Groundwater Management
Issue: As competition for groundwater increases there will be greater demands on planners and managers to deal systematically with social issues. These challenges will be more evident as water reform develops and allocation issues relating to groundwater become more urgent.
These issues are becoming more evident in both quantity and quality domains. Because of the need for increased public accountability, there is a requirement to deal systematically with factors such as risk perception and uncertainty, justice, fairness and ethics and fuzzy concepts such as beneficial use. The nature of diffuse sources of pollution of groundwater also demands better understanding of how social and institutional arrangements for management at a catchment level can be more effective. These are examples of problems which necessitate the development of a focussed social research activity.
This social research should interlink as much as possible with the other areas of the CGS's operations. Nevertheless, it should also make a contribution to the development of social science theory and practice in this area in its own right. Thus on many occasions, such as the BP project outlined below, the social research can be mapped in the social and the generic groundwater sector.
Projects and contacts: - Fairness and Justice in Groundwater Allocation.
Contact: Ms Blair Nancarrow - Membership of Expert Panel on Groundwater Allocation in the Namoi Valley.
- The Importance Aesthetics in the Level of Diesel Treatment in Decommissioned Petrol Stations.
- Stage 2 Aesthetics Study BP
- Groundwater allocation in the Fitzroy Catchment, Queensland. (Joint Proposal with University of Central Queensland)
Contact: Dr Geoff Syme
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