Protect our groundwater
February: Record flood at Baralaba
Groundwater is water found underground in soil, sand and rock. Groundwater can be connected to the surface, and water can move from the surface into groundwater, or from groundwater to the surface. Water moves through groundwater systems (aquifers) at different speeds, and water quality reflects the material that groundwater moves through.
Groundwater performs three important functions:
- stores, purifies through filtering and nutrient cycling, and releases water
- provides habitat for organisms
- provides water for a variety of other ecosystems.
Groundwater-dependent ecosystems rely on groundwater for all or part of the time and are often of high conservation value. Groundwater-dependent ecosystems can include springs, aquifers and caves, some rivers and wetlands, some terrestrial vegetation and some estuarine and near-shore marine ecosystems. For example, the Boggomoss Springs in the Upper Dawson are fed by Great Artesian Basin aquifers.
Groundwater provides an important water source for some communities and industries. Directly and indirectly, groundwater contributes to social and recreational values. Traditionally, springs would have been an important resource for Indigenous people and they retain cultural significance today.
The Groundwater fact sheet gives an overview of the current state and trends of this regional asset.
Mapping the key values and indentifying areas that are at risk is an important tool for managing these assets effectively. The mapping tool below allows stakeholders to access specific data that can be used as a basis for sound decision making. If you are using an iPad or iPhone to access the CQSS:2030 website, please click on the mapping application button below to access it.
For more complete and detailed geographical data, or if you are using an iPad or iPhone, please visit the detailed map application by clicking the link below. You will be taken from the CQSS:2030 website to a powerful mapping application that draws on a richer data set.
In central Queensland
Regional groundwater systems include sedimentary, fractured rock and alluvial aquifers, as well as deeper aquifers such as the Great Artesian Basin. Shallow aquifers generally follow the surface landform, while deeper aquifers follow the underlying geology.
Groundwater resources across the Fitzroy Basin vary considerably and are significantly influenced by local geology. About a third of the region’s groundwater is saline.
Groundwater is used extensively for crop irrigation, stock and domestic use as well as town water supplies. The Great Artesian Basin is mostly used for stock watering. Major rainfall events in recent years have recharged most of the aquifers.
Although there are many bores in the region, monitoring of groundwater supplies is limited, and has declined in recent years. Groundwater-dependent ecosystems are poorly understood.
Groundwater levels fluctuate with recharge and discharge of water over time. When extraction of groundwater exceeds the natural recharge rate, water levels or pressures can drop. Groundwater depletion is an issue in the major alluvial aquifers throughout the region, particularly in the Callide groundwater area.
In some areas, tree clearing or excess irrigation has caused recharge to increase. If water tables rise to near the land surface this can cause salinity in the soil and groundwater. This can impact local stock and domestic water supplies, as well as soil health and water quality in local streams.
The soil and rocks that groundwater flows through can cause its quality to be naturally poor. Contamination can also occur when material enters the groundwater from land or water management practices. This is a risk with fertilisers and pesticides applied in cropping systems, chemicals and saline water generated in mining and gas operations, and hydrocarbons and other materials in industrial or urban areas.
Other processes such as dryland salinity, exposure of acid sulfate soils and the migration of existing saline water to freshwater areas can also decrease groundwater quality.
Coal seam gas extraction produces large volumes of saline groundwater through ‘de-watering’ deep coal beds. Risks include impacts on the connected groundwater systems’ water levels, pressures and quality. The water extracted must be disposed of carefully to avoid salinisation of land and water resources.
Similarly, the expansion of large, open-cut coal mines may affect local groundwater supplies though ‘drawdown’ of groundwater levels.
Good rainfall in recent years has fully recharged most of the region’s aquifers. However, groundwater depletion is expected to continue and levels fall as extraction exceeds supply in most alluvial aquifers. Recent and potential future tree clearing will increase the existing risks of dryland salinity.
Coal seam gas extraction is rapidly expanding in parts of the region. Risks associated with groundwater impacts, including disposal of saline water extracted from coal seams is of concern. Land use intensification will also increase the risk of local groundwater contamination.
Climate cycles are a key determinant of groundwater levels. Extended droughts will reduce salinity risks, while aquifers are drawn down. High rainfall years will recharge aquifers and increase the salinity risk.
Groundwater is a critical part of the water cycle and supports high-value ecosystems as well as drinking, stock and irrigation water. Risks from over-extraction, salinity and contamination will continue to put pressure on this resource. Key groundwater attributes that need to be managed include water levels and pressures, groundwater quality and groundwater-dependent ecosystems.
A groundwater monitoring network is managed by the Department of Natural Resources and Mines, and coal seam gas and open cut coal mining companies also monitor groundwater in their areas of operation.
Modelling of salinity risk has been completed for the region (NRM, 2007).
A Water Resource Plan and Resource Operations Plan have recently been revised for the region and includes groundwater management areas.