A clean and safe supply of groundwater is essential for the drinking water needs of country towns, several major industries, especially agriculture and to support groundwater dependent ecosystems. Groundwater quality decline and contamination creates a serious threat to human and animal health and the degradation of wetlands and rivers.
The NSW State Groundwater Quality Protection Policy (PDF 1.2 MB) provides a comprehensive set of policy principles for groundwater quality protection. It also provides guidance on groundwater quality protection to resource managers. The objectives of the policy are achieved by applying the following management principles:
- All groundwater systems should be managed to ensure their most sensitive identified beneficial use (or environmental value) is maintained
- Town water supplies should be afforded special protection against contamination
- Groundwater pollution should be prevented so that future remediation is not required
- For new developments, the scale and scope of work required to demonstrate adequate groundwater protection shall be commensurate with the risk the development poses to a groundwater system and the value of the groundwater resource
- A groundwater pumper shall bear the responsibility for environmental damage or degradation caused by using groundwaters that are incompatible with soil, vegetation or receiving waters
- Groundwater dependent ecosystems will be afforded protection
- Groundwater quality protection should be integrated with the management of groundwater quantity
- The cumulative impacts of developments on groundwater quality should be recognised by all those who manage, use, or impact on the resource
- Where possible and practical, environmentally degraded areas should be rehabilitated and their ecosystem support functions restored.
On a national level, guidelines have been developed to provide a framework for protecting groundwater contamination in Australia and are part of the National Water Quality Management Strategy. The protection framework involves the identification of the specific beneficial uses of every major aquifer, with strategies which can be applied to protect those beneficial uses.
A particular risk to groundwater sources is contamination by leakage into the water table of pollutants from industrial sites, fuel storage tanks, septic systems, land fill sites, garbage dumps, abattoirs, cattle feedlots and piggeries. The Office of Environment and Heritage is the lead agency responsible for managing contaminated groundwater and developing groundwater clean-up strategies for contaminated sites. The NSW Office of Water assists by supplying technical information, establishing the beneficial use of aquifer systems and restricting the take of groundwater, if necessary.
Because of the numerous contaminated sites in the Botany Bay area the NSW Office of Water has developed a management approach for the Botany Bay sand aquifers.
The National Water Commission and the NSW Office of Water have funded a large scale investigation into the chemical characteristics of groundwater to improve our understanding of the possible impacts of high volume groundwater pumping on groundwater quality.
The studies, undertaken in collaboration with consultant Parsons Brinckerhoff, took place in the high-yielding aquifers of the Namoi, Macquarie, Lachlan, Murrumbidgee and Murray valleys, all within the NSW part of the Murray-Darling Basin. Over one thousand groundwater samples were taken from government-owned monitoring bores and private production bores.
To understand the processes affecting groundwater salinity, a broad range of chemicals were analysed including major ions, trace elements, nutrients and stable isotopes. The results were studied to characterise the chemical make-up of the water, assess where the groundwater was recharged from and analyse aquifer mixing processes. Spatial and temporal trends were identified, an assessment made of the beneficial use of the water, and any areas at risk to groundwater quality deterioration were identified.
The results of this study will be used to strategically refine the Office of Water's groundwater monitoring program to focus on areas where groundwater quality deterioration was found, while keeping a broad eye on groundwater quality in other important high-use locations.
Consultant's report: Characterisation of hydrogeochemistry and risks to groundwater quality (PDF 9.6 MB)
A valuable tool used for groundwater quality protection is 'groundwater vulnerability mapping'. These maps show the vulnerability (or level of risk) of aquifers to contamination relating to physical characteristics of the location, such as the depth to the water table and soil type. The maps should be used by groundwater managers, planners, developers, and regulating agencies to make better informed judgements on where to locate potentially polluting activities so as to minimise the risk to groundwater.
Groundwater vulnerability maps are available for a number of catchments in NSW. These maps are accompanied by explanatory notes to guide their use and explain how the maps were created.
- Castlereagh vulnerability map (PDF 846 KB)
Notes for the Castlereagh vulnerability map (PDF 320 KB)
- Lachlan vulnerability map (PDF 157 KB)
Notes for the Lachlan vulnerability map (PDF 325 KB)
- Macquarie vulnerability map (PDF 141 KB)
Notes for the Macquarie vulnerability map (PDF 324 KB)
- Macintyre vulnerability map (PDF 1.3 MB)
Notes for the Macintyre vulnerability map (PDF 323 KB)
Each map is accompanied by notes which explain how the maps were created and how to use them.