The Queensland Bulk Water Opportunities Statement provided a framework for sustainable, regional economic development through better use of existing water infrastructure and appropriate investment in new infrastructure. An initiative from the statement was the need to consider alternative technologies and approaches to traditional bulk water supply infrastructure. Alternative technologies include several underground technologies, more commonly referred to as Managed Aquifer Recharge. The Underground Technologies project focused on mapping the prefeasibility potential of alluvial areas in Queensland for creating augmented groundwater storages using sand dams and sub-surface dams.
Previous sand dam and sub-surface dam site assessments involve multi-stage, multi-component analysis utilising Geographical Information Systems that are variants of Preference Ranking Organization Method for Enrichment Evaluations methods and follow a Multi-Criteria Decision Making process. These methodologies are customised for drainage sub-catchment scale assessments and are reliant on detailed mapping and high resolution data. Previous methodologies are not suited to multi-drainage catchment scale investigations due a lack of detailed mapping data, differences in data resolution and incomplete spatial data coverage.
A modified methodology was developed to address limitations associated with the multi-drainage catchment scale investigation. Publically available datasets were assessed for suitability. Attribute data in each dataset was characterised, classified and ranked. These datasets were then ordered, overlaid and processed in ArcGIS to integrate and classify attribute combinations to indicate prefeasibility potential.
The sand dam and sub-surface dam prefeasibility mapping products including GIS datasets, are the key outputs from the Underground Technologies Prefeasibility Study. The mapping products are designed to display the relative state-wide potential for developing sand dams or sub-surface dams to augment groundwater supplies in alluvial sediment areas. Based on the assessment criteria, target areas are ranked to display their potential to host sites for sand dam or sub-surface dam development. The mapping products are designed to provide a guide for prioritising more detailed feasibility studies.