Perth: Administration
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. Under the Act, the right to the use, flow, and control of the water in watercourses, wetlands, and underground water sources is vested in the Crown.
The Western Australian Department of Water assists the Minister with the water resource management powers and functions set out in the Act, including the power to:
- proclaim water management areas across the State for surface water and groundwater
- regulate the abstraction of water from prescribed water management areas, including through the issuing of licences and the announcements of restrictions on licence use.
There are 15 groundwater management areas that were proclaimed by the Department of Water in the Perth region (Figure C10). All lie on the coastal plain (between the coast and the Darling escarpment).
Figure C10 Groundwater management areas within the Perth region
Surface water management areas proclaimed by the Department of Water in the Perth region are shown in Figure C2 in the 'Physical information'.
Water management plans
The Department of Water prepares water allocation plans to specify how water resources are to be shared between competing needs in particular areas. Water allocation plans define the water available for use from a particular water resource. 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.
Water allocation plans in place within the Perth region include:
- Cockburn Groundwater Area Water Management Plan
- Gnangara Groundwater Areas Allocation Plan
- Gingin Surface Water Allocation Plan
- Middle Canning River Surface Water Allocation Plan
- Murray Groundwater Allocation Plan.
All current allocation plans for the Perth region and supporting information can be accessed at the Department of Water website.
Environmental water management
Environmental water legislation
The Environmental Water Provisions Policy for Western Australia guides the Department of Water 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
Surface water
Environmental water provisions are specified in water allocation plans and are expressed as a water regime requirement, that is, a minimum flow regime that is to be achieved at key gauging station locations within the management area. Responsibility for achieving these flow regimes is placed on the storage operator and is defined in the licence conditions as part of operating strategies. The Department of Water monitors flows at each of these key gauging stations to ensure minimum flow regimes are maintained.
Studies are conducted to determine these water regime requirements as part of the development of surface water management plans. For example, in the Gingin Surface Water Allocation Plan the minimum flow regimes within the area were based on preliminary water regime requirements developed by Storey and Davies (2002). In the Middle Canning River Surface Water Allocation Plan the water regime requirements were developed by Radin et al. (2010).
Groundwater
Environmental water provisions specified in the water management plans are expressed as minimum groundwater levels within the management area. These minimum levels are maintained for the purposes of protecting key ecological values associated with the groundwater-dependent ecosystems. These provisions, which 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 guidelines under the Western Australian Environmental Protection Act 1986.
When environmental monitoring indicates there is a threat to the ecological health of a groundwater-dependent ecosystem, remedial action can be taken by the Department of Water, in conjunction with other organisations, for the best management of the ecosystem (e.g., announce a restriction on water extraction to particular users).
Cultural water management
The waterways and groundwater systems within the Perth region are important to cultural beliefs of the Nyungar people. Allocation plans do not quantitatively define water regimes required to support the cultural and social values of the rivers and groundwater-dependent features in the region; however, the cultural values are considered through environmental water provisions (see Environmental water management).
Organisations responsible for water management
The organisations responsible for water supply and management in the Perth region are listed in Table C1.
Organisation | Responsibility |
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