Aquifers

Aquifers are made up of layers of soil and rock that can soak up and hold on to water.

They're made out of fractured rock, limestone, gravel, sand, and sandstone.

Groundwater is stored in aquifers.

Types of aquifers

In the Northern Territory (NT), there are 3 main types of aquifers.

Fractured rock

These are made of hard rocks where groundwater is stored in the fractures, joints and bedding planes.

These rock types have minor porosity, so bores in these aquifers give low to moderate yields.

Fractured and cavernous

These are made of limestone or dolostone, which are often cavernous.

They can be highly productive. Springs like those at Mataranka are the outlets for this type of aquifer and often keep stream flows for part or all of the dry season.

Sedimentary basin (porous)

These are made of porous sediment such as sand, gravel and sandstone.

Groundwater is stored in and moves through the spaces between the sand grains. These are not as common in the NT as in other parts of Australia.

Two key examples in the NT are the:

• Great Artesian Basin (a small part of this is beneath the Simpson Desert)
• Ti-Tree Basin.

Such aquifers can be productive.