The Gnangara groundwater system is Perth’s largest and most important water resource. This plan sets out how the Department of Water and Environmental Regulation (WA) will manage the system to continue adapting to climate change.

Climate change has caused average annual rainfall to decline 15 per cent since 1975 (Perth Airport rainfall station). This decline, combined with groundwater abstraction, has lowered groundwater levels across the Gnangara groundwater system. As a result, the health of groundwater-dependant wetlands and vegetation is suffering, groundwater quality is reducing in some areas, and the long-term sustainability of the resource is under threat.

This groundwater allocation plan sets out the system’s water resource management objectives and how the government will use water licensing and other measures to:

• maintain or increase groundwater levels to avoid damage to water quality and environmental health at important locations
• reduce the rate of groundwater-level decline in other locations
• maintain a reliable water supply.