Gnangara groundwater allocation plan

The 2022 Gnangara groundwater allocation plan sets out how we will manage the Gnangara groundwater system – Perth’s largest natural water resource – to continue adapting to climate change.

The Gnangara groundwater allocation plan was released in June 2022.

Supporting documents for the plan are also available:

The statement of response summarises our response to public comments and submissions received on the Gnangara groundwater allocation plan: draft for public comment released in November 2021.

The plan details our approach to regulating and managing the take of groundwater in this area.

For more information on why a new plan is a necessary response to climate change, how water management is improving and what can be done to secure groundwater for the future visit gnangara.dwer.wa.gov.au.

Water allocation planning for the Gnangara system

Gnangara groundwater – Perth’s largest, most accessible, lowest cost source of fresh water – has become out of balance through less rainfall because of climate change, and continued groundwater use.

The Gnangara groundwater system is a shared resource. Gnangara groundwater supplies almost half of all the water used across Perth. This includes water for Perth’s Integrated Water Supply Scheme and water taken by farmers, local governments, schools, industry, and households from their own bores.

It also supports nationally significant groundwater-dependent ecosystems, such as wetlands and Banksia woodlands. These groundwater-dependent ecosystems support biodiversity, help create our 'sense of place' and make our city an attractive place to live.

The 2009 Gnangara groundwater areas allocation plan provided initial strategies to manage sustainable groundwater abstraction and first steps to returning the over-allocated system to balance, after 40 years of declining rainfall and recharge to groundwater. It was a strong first step in adjusting our groundwater management in the context of drier climate. 

The Department of Water and Environmental Regulation developed the 2022 Gnangara groundwater allocation plan to make sure we have a productive and sustainable groundwater supply and healthy environment under a drying climate.

To develop the Gnangara allocation plan, we consulted with water users to find ways to adjust and to bring our Gnangara groundwater system back into balance by 2032.

Plan area

The Gnangara groundwater areas cover about 2,200 km2 in the northern part of Perth.

The area covers the groundwater resources of the Yanchep, Gnangara, Wanneroo, Swan, Mirrabooka, Gwelup and Perth groundwater areas and includes a portion of the Gingin groundwater area.

For details on groundwater subareas see Chapter 1 of the plan.

Gnangara plan area and groundwater areas covered
Gnangara plan area and groundwater areas covered

Groundwater resources

The Gnangara groundwater areas consist of three main aquifers:

  • the unconfined Superficial aquifer (commonly known as the Gnangara Mound)
  • the deep, partly confined Leederville aquifer
  • the deep, mostly confined Yarragadee aquifer. 

Minor aquifers include the Mirrabooka, Coastal Saline and Fractured Rock aquifers.
 

The Gnangara groundwater system has three main aquifers and supports Perth’s water supplies, wetlands and bushland areas
The Gnangara groundwater system has three main aquifers and supports Perth’s water supplies, wetlands and bushland areas

Publications

Gnangara groundwater allocation plan

Gnangara groundwater allocation plan: Methods

Gnangara groundwater allocation plan: Statement of response

Gnangara groundwater allocation plan: draft for public comment

Gnangara groundwater areas allocation plan (2009)

Studying Perth's deep aquifers to improve groundwater management

Connectivity between the north Yeal wetlands and Perth's regional groundwater

Lake Nowergup - Factors in declining lake and groundwater levels

Loch McNess hydrogeology and causes of water-level decline 1975-2011

Page reviewed 4 August 2022