There are two legislative Acts that establish the framework for managing and allocating water resources in the Ord region:

• Western Australian Rights in Water and Irrigation Act 1914
• Northern Territory Water Act 1992.

Under the Acts, 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 and Environmental Regulation and the Northern Territory Department of Environment and Natural Resources assist their respective ministers with the water resource management powers and functions set out in the Acts, including:

• regulating the taking of water from prescribed water management areas
• proclaiming water management areas for surface water and groundwater.

Water management areas currently exist for the portion of the Ord region that lies within Western Australia, but not in the portion of the region within the Northern Territory. The following surface water management areas in the Ord region were proclaimed under the Rights in Water and Irrigation Act 1914 (as shown in Figure R8):

• Ord River and Tributaries
• Ord Irrigation District
• Wyndham Water Supply (a small area in the northwest near Wyndham).

Figure R8 Surface water management areas in the Ord region

The Canning–Kimberley groundwater management area in the Ord region was proclaimed under the Rights in Water and Irrigation Act 1914 as shown in Figure R9.

Figure R9 Groundwater management areas in the Ord region

The Department of Water and Environmental Regulation prepares water allocation plans to specify how water resources are to be shared between several needs in particular areas. Water allocation plans define the water available for use from a particular water resource. The plans also recognise the area's environmental values and ensure that sufficient water is retained in the resources to protect aquatic ecosystems and meet specific social and cultural needs.

The Ord Surface Water Allocation Plan applies to the Ord River and Tributaries and the Ord Irrigation District surface water management areas (as shown in Figure R8). The plan sets out how the department allocates and licenses surface water in the region to manage the demands of irrigation, hydroelectricity generation, and urban and individual supply. The plan also defines the environmental water provisions for the lower Ord River and is set with consideration for ecological, economic, and social impacts, including recognition of the cultural significance to the Miriuwung and Gajerrong peoples.

The surface water allocation plan has also been prepared to manage the increasing demands on water in the region, particularly with the Ord-East Kimberley Expansion Project (see Major water reforms in 'Climate and water'). Further information on the plan can be found at the Department of Water and Environmental Regulation website.

Water management plans and allocation plans have not been developed for groundwater resources in the region due to the limited use of groundwater compared to the availability.

The Environmental Water Provisions Policy for Western Australia guides the Department of Water and Environmental Regulation in water allocation 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 are specified in water allocation plans and are expressed as a water regime requirement, that is, a minimum flow regime to be achieved at key 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 Ord Surface Water Allocation Plan defines environmental water provisions to protect the ecological condition of the lower Ord River. Environmental water provisions are set with consideration for ecological, economic, and social impacts, including recognition of the cultural significance to the Miriuwung and Gajerrong peoples.

The Water Corporation of Western Australia has an obligation to operate water levels in Lake Argyle and Lake Kununurra and monitor releases to maintain specific flow rates in the lower Ord River. The Department of Water and Environmental Regulation monitors flows at key locations in the lower Ord River to ensure that water regime requirements are met. 

Further information regarding environmental water provisions for the 2016–17 year is provided in the Environmental benefit note in 'Supporting information'.

The Miriuwung and Gajerrong peoples hold native title rights to land and waters throughout the lower Ord River region (downstream of Lake Argyle). The Ord Surface Water Allocation Plan defines cultural water provisions that consider the Miriuwung and Gajerrong peoples' interests along the lower Ord River.

Short periods of low ('dry out') flows are important to Dreaming stories of the Miriuwung and Gajerrong peoples. Since dam construction, such 'dry out' flows in the lower Ord River are rare and generally only occur when maintenance or inspection work is carried out at the dams. The Department of Water and Environmental Regulation and the Water Corporation have an obligation to let the Miriuwung and Gajerrong peoples know when such work is undertaken so that traditional activities can be pursued during these periods.

More information on native title rights to water in the Ord region is provided in the Ord Surface Water Allocation Plan and the associated Ord Surface Water Allocation methods report (Department of Water 2012).

The organisations with management responsibilities for regulating water resources and supplying water services in the region are shown in Table R1.