Groundwater monitoring
Groundwater is the water stored beneath the Earth's surface, in the gaps between soil, rocks, and sand. This water can be accessed and used for a range of purposes – through bores. Monitoring groundwater helps us understand the quantity and quality of our groundwater resources, and how they change over time.
Groundwater is stored in an aquifer. An aquifer is made up of layers of rocks, sand or gravel that have spaces between them where groundwater can be stored. When it rains, some of the water seeps into the ground and trickles down through the soil and rocks. Eventually, it reaches the aquifer, where it stays stored in the tiny spaces between the materials. Aquifers lie beneath all parts of Victoria.
The water within aquifers varies from fresh water to saltier than seawater. Drought and climate change affect aquifers close to the Earth's surface. Deep aquifers are more resilient to changes in rainfall. Refilling deep aquifers can take many years.
State Observation Bore Network
Our State Observation Bore Network (SOBN) currently monitors water levels and the quality of groundwater at over 1400 bores across Victoria. Historic data is available in a further 1300 bores that are no longer actively monitored. A growing number of SOBN bores (40%) provide daily measurement which allows for more in-depth understanding and analysis of the groundwater resource.
Water temperature, salinity, and pH accompanies groundwater level measurement at more than 1200 current bores. Measures of alkalinity, nutrients, salts, ions, metals and other water quality may be found in the chemistry documents. These have been collected on multiple occasions rather than continuously over time, as part of projects or the spring sampling program.
Zoom to explore where we monitor groundwater and hover to see the latest measurements.
Viewing data in context
In the data portal you can put your data in context with these and many other layers:
- Victorian aquifer framework (VAF)
- Groundwater Management Units (GMU)
- Water supply protection areas
- Groundwater management basins
- Water table salinity and salinity provinces
- Registered Aboriginal Parties
- Management boundaries
Why monitor groundwater?
Groundwater monitoring helps us understand how groundwater systems work. and how they change, so that we can sustainably manage the resource.
Groundwater is constantly changing in response to recharge (seepage of new fresh or saline water), discharge (release of groundwater into springs or streams), water levels and land use.
Groundwater origin and aquifer geology influence the quality of groundwater and its suitability for use. Drawing down water tables can expose rocks to air, creating conditions that make harmful metals mobile in water, known as acid mine drainage. Seeping of water from agricultural runoff or sewage tanks can add large amounts of nutrients, salts and contaminants to groundwater. Monitoring groundwater chemistry help us determine groundwater flow paths and the relative age of the groundwater.
Groundwater is primarily used in Victoria for irrigation of crops and dairy farms; but it also supplies water for domestic and stock purposes, power generation and for town water supply. Monitoring lets us know how much water is available and its suitability for use.
SOBN monitoring data is used to:
- assess the size of resource and how it is changing for long term policy
- develop and administer Local Management Plans for Groundwater management areas and Water supply protection areas
- determine groundwater resource allocation, the percentage of licence entitlement that may be extracted in a season
- Assess licence applications to take and use groundwater and set suitable conditions to protect the rights of other users and environment from over extraction
- Protect groundwater dependant ecosystems and maintain connection for wetlands
- Account for water availability, trends, use and trade
- Undertake technical assessments, modelling, risk assessment.
Reviewed 01 August 2024