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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 be connected to surface water, which includes the water in our rivers and wetlands.

Groundwater explained

Key facts about groundwater

  • Water existing below ground level is called 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 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 First 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.

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.

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

Sustainable management

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

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 on the amount of groundwater that can be taken from the Basin.

These limits are called sustainable diversion limits.

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

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.

 

 

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
  • the amount of water flowing into (recharging) groundwater systems.

The MDBA 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.

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

Strategic Groundwater Research Partnership

The MDBA has an ongoing commitment to improve knowledge and management of the Murray–Darling Basin. The MDBA recently funded a three-year, $2 million strategic groundwater research project. The research was in partnership with the National Centre for Groundwater Research and Training at Flinders University.

The project goal was strategic research to support groundwater knowledge and management in the Murray–Darling Basin.

The research examined critical scientific issues with a focus on understanding and managing the interaction between surface and groundwater, as well as increasing the understanding of groundwater recharge processes and estimation techniques.