National Water Account 2019

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Key findings

Climate and water

Water Accounting Statements

Supporting information

Region description

Reference information

Perth: Water management

Surface water and groundwater management

Water legislation

• The Western Australian Rights in Water and Irrigation Act 1914 establishes the legislative framework for managing and allocating water resources in Western Australia.

• The Western Australian Department of Water and Environmental Regulation assists the Minister with functions set out in the Act, including proclaiming water allocation areas, and regulating the taking of water from these areas.

Water allocation areas

Figure R9 Groundwater allocation areas within the Perth region

• There are 16 groundwater allocation areas that were proclaimed by the Department of Water and Environmental Regulation in the Perth region.
• All groundwater allocation areas lie on the coastal plain between the coast and the Darling escarpment.

Figure R10 Surface water allocation areas within the Perth region

• There are 15 surface water allocation areas defined by the Department of Water and Environmental Regulation within the Perth region, covering all of the rivers in the region.

Water management plans

• The Department of Water and Environmental Regulation prepares water allocation plans to specify how water resources are to be shared between competing needs in particular areas.

• Each plan also recognises its area's environmental values and ensures that sufficient water is retained in the resources to protect water-dependent ecosystems and meet specific social needs.

• There are 8 groundwater allocation plans and 3 surface water allocation plans in the Perth region.
• All current allocation plans for the Perth region and supporting information can be accessed at the Department of Water and Environmental Regulation website.

Environmental water management

Environmental water legislation

• The Environmental Water Provisions Policy for Western Australia guides the Department of Water and Environmental Regulation in planning and decision-making in relation to allocating water to the environment.

• The policy describes the role of environmental water regime requirements and environmental water provisions in setting the sustainable diversion limit of a water resource.

Environmental water provisions

• Environmental water provisions are specified in water allocation plans.

• In surface water management plans, these provisions are often expressed as required flow regimes. Responsibility for achieving these flow regimes is placed on the storage operator and is defined in the licence conditions as part of operating strategies.

• In groundwater allocation plans, environmental water provisions are often expressed as minimum groundwater levels at key sites to protect ecological values associated with the groundwater-dependent ecosystems.
• Groundwater levels provisions that were first identified in the mid-1980s for the Gnangara water table aquifer and in the early 1990s for the Jandakot water table aquifer, are now ministerial conditions under the Western Australian Environmental Protection Act 1986.

• The Department of Water and Environmental Regulation is responsible for monitoring environmental outcomes and enforcing environmental provisions.

• Further information regarding environmental water provisions for the 2018–19 year is provided in the Environmental benefit note in 'Supporting information'.

Cultural water management

• The waterways and groundwater systems within the Perth region are important to cultural beliefs of the Nyungar people.

• Cultural and social values of the rivers and groundwater-dependent features in the region are considered through environmental water provisions in the allocation plans.

Organisations responsible for water management

• Organisations responsible for water supply and management in the Perth region shown below.