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Groundwater

Groundwater is the water that sits beneath the earth’s surface. It is stored in fractured rocks, porous rocks and soils called aquifers or groundwater systems. Groundwater can connect to surface water, which includes the water in our rivers and wetlands. Management of groundwater is important to preserve and improve water quality and to support management of surface water.

Key facts

Water existing below ground level is groundwater.

Groundwater and surface water are connected and must be jointly managed for river health  and the health of the Basin.

Sustainable diversion limits set the limit of groundwater that can be used.
There will be 19 water resource plans to manage groundwater resources in the Basin.

Some rivers and river ecosystems in the Murray Darling Basin fully or partly rely on groundwater to survive.

Some communities in the Basin rely on groundwater reserves for drinking water.

Groundwater is often used to maintain water supply and keep fish and aquatic animals alive in times of drought.

 

Groundwater in the Basin is used for drinking water, agriculture, industries and for the environment.

Groundwater supports the environment in many ways. Some plants are completely dependent on groundwater for their needs. River red gums are an iconic species with deep roots that access groundwater.

Groundwater is important for ecosystems in caves. It is the water source and pressure for springs and supports rivers and wetlands. Many groundwater dependent ecosystems are also significant cultural places for Aboriginal nations.

In the past, the complexity and importance of groundwater has not been well recognised in water management. The connection between groundwater and surface water has not been well understood. This led to inadequate management of this precious and finite resource, resulting in issues associated with access and water quality.

The sustainable use of groundwater is vital to the health of the Murray–Darling Basin.

Groundwater and surface water, like rivers and wetlands, can be highly connected and need coordinated management. When groundwater is very connected to surface water, it can provide permanent pools for fish and other aquatic animals. This is very important when there are shortages in surface water.

Recharging groundwater takes time

In some systems groundwater may flow quickly over days or weeks, in other systems flow may be very slow, taking decades or longer to move through. Basin states consider individual aquifer properties and manage areas differently to suit.

Under the Basin Plan, Basin state and territory governments will manage both surface water and groundwater resources through water resource plans.

Sustainable management

It is possible to better measure and manage groundwater sustainably and the Basin Plan provides a framework to facilitate this.

For the first time, under the Basin Plan, Basin-wide limits have been set for the amount of groundwater that can be taken from the Murray–Darling Basin.

These limits are called sustainable diversion limits.

To make sure groundwater use is within the sustainable limits over the long-term, Basin state and territory governments have rules about how and when groundwater can be taken. They monitor and report on how much groundwater is being used each year.

Maintaining groundwater health

We work with Basin state governments to monitor and manage the Basin’s groundwater resources to make sure they are healthy and productive.

Groundwater resource monitoring looks at changes in the water level or pressure in a groundwater resource. This tells us the amount of water that:

  • can be sustainably taken from groundwater systems
  • is flowing into (recharging) groundwater systems.

We also monitor salinity levels in some groundwater systems because saline groundwater flow is a health risk for the environment, including our trees, grasslands, rivers and wetlands.

Unlike surface water, groundwater resources can take longer to recharge — or refill with water — when water is taken. This may be weeks, months, years or even hundreds of years in some systems.

This means the long-term management of groundwater resources is needed, to ensure the amount of water taken is sustainable.