A historic decline in rainfall is forcing a strict reduction in the groundwater used to maintain Perth's public green spaces and agriculture.
Perth sits on the Swan Coastal Plain and has historically relied heavily on vast underground aquifers for its drinking water, agriculture, and public green spaces. However, the region has been experiencing a long-term drying trend, with winter rainfall dramatically decreasing over the past few decades due to shifting climate patterns.
The declining rainfall profile means the groundwater systems are no longer naturally recharging at a sustainable rate. To secure the domestic drinking water supply, the state relies extensively on massive seawater desalination plants and advanced groundwater replenishment (treating wastewater and injecting it back into aquifers).
Because the public water supply is largely insulated by desalination, the focus is increasingly on non-potable water use. The state is systematically reducing groundwater allocations for local councils, schools, and agriculture. This means public parks, sports clubs, and urban tree canopies face stricter watering limits moving forward.
Local councils are deeply concerned about the reduction in groundwater allocations, warning that large swathes of public green space could dry out and die off. This creates a conflict between essential long-term water conservation and the need to maintain an urban tree canopy to combat the "urban heat island" effect during Perth's notoriously hot summers. Agricultural users on the fringes of the city also warn that tightening restrictions threaten local food production.
Keep an eye on the development of future desalination infrastructure and the strategic decisions local governments make as their groundwater licenses shrink. The transition to more drought-tolerant public landscaping is likely to visibly change the aesthetic of Perth’s suburbs over the coming years.