Groundwater is the water stored in geological formations below the earth's surface. When rain falls on land, some water evaporates, some flows into streams and some seeps into the soil and is absorbed by plant roots. Excess water in the soil may seep further down until it reaches the water table, where all the openings in the soil or rock are saturated with water. Water below the water table is called groundwater. The type of geological formation determines the quantity of water that can be accessed for use.
Groundwater is critical to the health of ecological communities and the viability of the agricultural, pastoral, mining and tourism industries in South Australia. It is also used for domestic water supply, irrigated horticulture, industrial applications such as beverage manufacture, linen washing and irrigation of recreational and sports fields throughout the metropolitan area.
There will be increasing demands on groundwater in the future due to projected growth in the mining, petroleum, and geothermal industries and how we all manage this resource will be critical.
As the largest source of fresh water in the state, it is important to understand the groundwater systems in order to manage risks to water quality and supply.
Many of the groundwater resources across South Australia are prescribed and managed through the state’s water licensing system to ensure water use remains sustainable. Find out more about how our water resources are managed.
Managing the use of groundwater
The use of groundwater is managed carefully as its ability to replenish is limited even though it is usually a renewable resource. This is because groundwater moves very slowly, usually less than one metre per day. Groundwater systems have also established, over time, a balance between the rates of inflow (recharge), outflow (discharge) and the volume of water stored. Any new use of groundwater from a system will cause a change in this balance. Groundwater management aims to understand how these systems operate so water quality and quantity are maintained and use is sustainable into the future.
It is also important to consider that inappropriate waste disposal and land use activities can impact on groundwater because it sits beneath our urban and rural communities. There is a high risk from many pollutants as they can seep into groundwater, affecting its quality. These include sewage, effluent, heavy metals, petroleum fuels, solvents, herbicides, fertilisers, concentrated livestock excretion, nutrients, salt and detergents. Practices that adversely impact groundwater are regulated by the EPA to protect these resources.
Desalination plants are located across South Australia and treat groundwater to remove salt and impurities.
Eight desalination plants are operated by SA Water to provide drinking water to regional communities. The plants are located at Hawker, Leigh Creek and the APY Lands and Yalata.
More information about the desalination plants can be found on the SA Water website