1.1.4 Hydrogeology and groundwater quality


This summarises the groundwater around and above the coal-bearing formations in the Maranoa-Balonne-Condamine subregion. The Maranoa-Balonne-Condamine subregion includes groundwater systems in alluvial aquifers associated with major rivers (and antecedent systems), basalt aquifers associated with the Main Range Volcanics Formation and aquifers of the Surat Basin within the Great Artesian Basin (GAB). The Maranoa-Balonne-Condamine subregion lies within the Murray–Darling Basin and the above-mentioned groundwater systems are included in the Commonwealth’s Basin Plan 2012, with the exception of the GAB formations in the northern part of the Maranoa-Balonne-Condamine subregion.

Throughout the subregion, groundwater is widely extracted for stock and domestic purposes, and – to a lesser extent – for town water supply and intensive agriculture. Groundwater extraction for irrigation is concentrated within alluvial aquifers flanking the upper reaches of the Condamine River, sections of the Macintyre and Dumaresq rivers, Macintyre Brook and an area north-west of St George. Across the entire subregion, aquifers of the GAB are a major water source for stock and domestic and town water supply purposes. In addition, a significant amount of groundwater is extracted from the Walloon Coal Measures of the GAB sequence, as a by-product of coal seam gas production.

Within the Maranoa-Balonne-Condamine subregion, groundwater monitoring has historically been undertaken by state water agencies for a variety of purposes including water level, water quality and salinity monitoring. Monitoring is focused on priority groundwater areas including the GAB, Condamine Alluvium, Border Rivers Alluvium and the St George Alluvium and basalts of the Main Range Volcanics Formation. More recently, an increasing amount of groundwater monitoring is undertaken by coal seam gas and mining companies, as is required under the current Queensland regulatory framework and Australian Government approval conditions.

Groundwater flows in the alluvial groundwater systems, with the exception of the Condamine Alluvium, are generally topographically driven with lateral flow directions similar to that of major drainage. Areas of potential inter-formational flow from alluvial aquifers into GAB formations exist across parts of the subregion, where water levels in the alluvium are higher than in the GAB formations.

Groundwater flow in intake beds and in the uppermost formations of the GAB is to the south and south-west.

The NSW Government undertakes groundwater planning and management via water sharing plans. Water sharing plans allow for management of individual groundwater systems and are effective for ten years from their date of commencement. Groundwater planning and management is undertaken by the Queensland Government via water resource plans. Water resource plans are subordinate legislation under the Commonwealth’s Water Act 2007, prepared at a river basin scale, and they specify the outcomes and strategies that will be used for each plan area. They expire after ten years unless they have been formally extended. Groundwater is not managed in every water resource plan. Sustainable yield (considering an integrated surface water – groundwater assessment) was not available for the three water resource plans in the Maranoa-Balonne-Condamine subregion. Resource operation plans implement the outcomes and strategies specified in the water resource plans.

In response to coal seam gas development in the Queensland portion of the Surat and southern Bowen basins, the Queensland Government has established a cumulative management area to enable monitoring and assessment of the cumulative impacts of coal seam gas activities upon groundwater resources. Within the Surat Cumulative Management Area, the Queensland Office of Groundwater Impact Assessment is responsible for assessing impacts and establishing integrated management arrangements in the Underground Water Impact Report for the Surat Cumulative Management Area (QWC, 2012). The Underground Water Impact Report obliges coal seam gas companies to undertake monitoring and in some cases construct new monitoring points.

Last updated:
5 January 2018
Thumbnail of the Maranoa-Baloone-Condamine subregion

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