Gnangara Mound - a unique water resource
The Gnangara Mound is Perth's largest source of groundwater, stretching from Gingin in the north to the Swan River in the south.
It is commonly referred to as the superficial (shallow or unconfined) aquifer overlaying deeper confined aquifers. The Gnangara Mound supplies water for a number of different purposes including:
- supporting local wetland and lake ecosystems
- supplying up to 60% of Perth's drinking water
- supplying irrigation for horticulture and agriculture in the Wanneroo and Swan areas and
- supplying irrigation for public open space and garden bores.
Wetland and groundwater levels on the Gnangara Mound have been under considerable pressure in recent years due to a combination of:
- A drying climate (less rainfall);
- Dense vegetation (native and pine plantations) limiting recharge; and
- Abstraction for irrigation and public water supply.
In particular, the drop in groundwater levels has impacted a number of different groundwater dependent ecosystems (GDEs) on the Gnangara Mound.
In a few areas, decreasing groundwater levels also have the potential to expose acid sulfate soils, which can significantly reduce water quality.
The Department of Water is managing the groundwater resource by controlling abstractions that might affect the environmental values associated with groundwater dependent ecosystems.
Learn more about the background and details of the Gnangara Mound.
Learn more about the Gnangara Sustainability Strategy.
Learn more about planning for the Gnangara groundwater areas.
Learn more about metering on the Gnangara Mound.
View the Review of ministerial conditions on the groundwater resources of the Gnangara Mound.
Please note: A number of errors were detected in Appendix E of this report. The report was amended and a revised edition made available for downloading on 17 January 2008. If you have any queries please contact Megan McGuire at the Department of Water.