Management of saltwater intrusion in coastal aquifers in Queensland, Australia

Maintenance and Update Frequency: unknown | Statement: Unknown | Many Queensland rivers have extensive deltas, which have large reserves of groundwater. These deltas contain fertile land suitable for intense agricultural development with associated towns and industry, all relying on groundwater for their water supply requirements. In some areas, extensive water use, especially in dry times, has resulted in saltwater intrusion into the aquifers. Management techniques have had to be developed and implemented to ensure the sustainability of these supplies. Individual hydrological situations have to be managed in different ways to take full advantage of the resources available. Options for management include artificial recharge schemes where conditions are suitable and surface water is available, or the provision of supplementary supplies from surface water storages to relieve demand on the groundwater resources. Restrictions on use may have to be applied during dry period and, in some cases, deliberate overuse with subsequent intrusion of saltwater has been permitted to encourage agricultural development of certain areas, with surface water being supplied when it became available. Extensive monitoring of groundwater levels and quality is carried out to detect any movement of the freshwater/saltwater interface. Models are used to predict future movement. The experience in Queensland has been that engineering works, coupled with management linked to predictive groundwater models, can reduce saltwater intrusion and provide high sustainable yields from coastal aquifers.