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Ord

                                                                                                   

Physical Information

                             

This page provides details about the region, its water resources, land use and water-related infrastructure.

 

General description

Area: 65,800 km²
Population: 11,300 (based on the Kimberley Statistical Division: Ord subdivision) (ABS, 2011)

The Ord region is located in the East Kimberley region of Australia, as shown in Figure P1. The region straddles the border between Western Australian and the Northern Territory, with about 75% of the region lying in Western Australia.

Figure P1. Map of the Ord region within Australia

Figure P1. Map of the Ord region within Australia

The boundary of the Ord region is physically defined by two surface water basins; the Ord River Basin and the Keep River Basin, as shown in Figure P2.

Figure P2. Contextual map of the Ord region

Figure P2. Contextual map of the Ord region

Ord River Basin

Catchment area: 53,800 km² (Department of Water, 2006)

The Ord River Basin and associated Ord River catchment is one of the major river systems in northern Australia and forms the greater part of the Ord region. It extends from the Kimberley Plateau in the south and discharges into the Cambridge Gulf near Wyndham, via the Ord River Estuary.

The Ord River Basin includes the King River, which is of particular importance to the town of Wyndham's water supply.

Keep River Basin

Catchment area: 12,000 km² (Department of Sustainability, Environment, Water, Population and Communities, 2009)

The Keep River Basin lies is in the northeast of the Ord region. It extends from the Pinkerton Range in the southeast of the basin and discharges into the Timor Sea.

Description of the region

The Ord region is physically defined by the boundaries of the Ord River and Keep River Basins and includes all water resources within or beneath the physical area.

The region includes water stored in and transactions related to:

  • surface water storages in the region
  • river channels within the region
  • water held in pipes and infrastructure as part of urban water supply and wastewater networks
  • groundwater aquifers beneath the region.

The Ord region excludes water stored in and transactions related to:

  • private water storages, such as farm dams and private commercial water storages used to harvest runoff or collect rainwater
  • water held in the landscape, such as soil moisture, and water held in wetlands that are not connected to surface water storages.

For more information regarding items in this water accounting report, please refer to the significant water accounting policies.

 

Land use

The Ord region contains several urban centres, remote stations and Aboriginal settlements. The largest urban centres in the region are:

  • Kununurra – population 5,600
  • Halls Creek – population 3,300
  • Wyndham – population 800.

Other settlements in the region include Warmun, Durack, and Lake Argyle Village.

Major land uses in the Ord region include:

  • irrigated agriculture
  • mining
  • pastoral grazing
  • parks and reserves.

The relative area of each major land use in the Ord region is shown in Table P1 and Figure P3.

Table P1. Land use in the Ord region (ABARES, 2010)

Land use

Area (km2)

Area (%)

Conservation and natural environments

12,742

19

Grazing

52,112

80

Forestry

37

<0.1

Dryland agriculture

53

<0.1

Irrigated agriculture

150

<0.1

Urban

9

<0.1

Other intensive uses

0

0

Mining

0

0

Water

697

1

Total

65,800

100


Figure P3. Map of land use in the Ord region

Figure P3. Map of land use in the Ord region

Most irrigated agriculture occurs in the Ord River Irrigation Area and areas adjacent to the Ord River that have access to water for irrigation. A variety of crops are grown in these areas; the major crops being sandalwood, mahogany and a range of horticultural crops and grains.

Key mining activities in the region include diamonds and nickel. Argyle Diamond Mine is situated near Lake Argyle and uses water from Lake Argyle for its operations. Nickel is also mined approximately 120 km north of Halls Creek.

Pastoral grazing occurs throughout the region and is characterised by cattle grazing on large stations.

There are over 4,000 km² of parks and reserves in the Ord region, including Purunululu (Bungle Bungles) National Park, Keep River National Park and Parry Lagoons Nature Reserve. These areas are of cultural significance and form the basis of the tourism industry in the region.

 

Significant aquatic ecosystems

The region contains several significant aquatic ecosystems, as shown in Figure P4:

Figure P4. Map of significant wetlands in the Ord region

Figure P4. Map of significant wetlands in the Ord region

The Ord River and associated aquatic ecosystems have a strong cultural significance for a number of Aboriginal tribes, particularly the Miriuwung and Gajerrong people. Further information is available in the study of Aboriginal Cultural Values of the Ord River and Wetlands (2003).

 

Water resources

There are four major surface water resources in the Ord region, and two groundwater resources:

  • Lake Argyle
  • Lake Kununurra
  • the Ord River channel, downstream of Lake Kununurra
  • Moochalabra Dam (King River)
  • groundwater aquifers – Kununurra and Halls Creek
  • tributaries of the Ord River, upstream and downstream of Lake Argyle.

Surface water resources support the main water users in the region, including irrigated agriculture (80% of water abstracted), commercial forestry (10%) and urban and self-supply licencess (5%).

Groundwater resources in the region are primarily used for mine de-watering and operations, as well as for
urban supply (5%).

 

Surface water

Surface water resources of the Ord region are highly developed due to the Ord River Irrigation Scheme. Lake Argyle is used to supply water to the irrigated agriculture and forestry. Other minor storages and tributaries are used to supply townships and self-supply irrigators.

Major storages

A major storage is any water storage that has a storage capacity of 1 GL (1,000 ML) or more, as defined in the Water Regulations 2008. Details of major storages in the Ord region are listed in Table P2, and a map of their location within the region is shown in Figure P5.

Table P2. Major storages in the Ord region (Source: Water Storage)

Storage

Total storage capacity (ML)

Dead storage capacity (ML)

Purpose of water supply

Lake Argyle

 

10,755,830

324,000

Releases for hydro-electric power generation
Releases for environmental water provision
Releases for irrigation
Mining
Urban supply

Lake Kununurra

 

100,825

87,000

Directly receives releases from Lake Argyle
Supplies Ord River Irrigation Area
Supplies adjacent self-supply irrigators

Moochalabra Dam

 

2,023

175

Town supply for Wyndham

Total

10,863,175

411,175

 

 

Figure P5. Map of major storages in the Ord region

Figure P5. Map of major storages in the Ord region

Lake Argyle

Lake Argyle is formed by the Ord River Dam, and collects runoff from the Ord River catchment. Annual runoff varies dramatically; a reflection of the highly variable nature of rainfall and runoff across the region. Water is released from Lake Argyle for hydro-electric power generation, and the resulting flows are used to supply downstream users and meet environmental water provisions in the lower Ord River.

The Argyle Diamond Mine can also abstract under licence from Lake Argyle if their private water storages are insufficient. 

Lake Kununurra

Lake Kununurra is formed by the Kununurra Diversion Dam, and the majority of inflows come from water released from Lake Argyle. Runoff from the catchment between the Lake Argyle and the Kununurra Diversion Dam (approximately 1,000 km²) also contributes inflows into the lake during the wet season. The lake is primarily used to supply water to the Ord River Irrigation Area, and other small scale irrigation. Water supplied to the Ord River Irrigation Area represents almost 90% of the total surface water entitlements in the Ord region.

Moochalabra Dam

Moochalabra Dam is a minor storage and is located on the King River. It is used for urban water supply for the town
of Wyndham.

Arthur Creek Dam

Arthur Creek Dam, located on the Dunham River, is a large private storage in excess of 20,000 ML. The storage is used for self-supply irrigation. The volume of the storage, and the water abstracted from it, is not included in the Ord region report because it is a private storage.

Rivers

Seasonal flow characteristics of rivers within the Ord region reflect the annual rainfall pattern of the region. Most of the rainfall occurs during the wet season between November and March. Outside of this period, flows are very low or cease to flow during the dry season between April and October (Figure P6).

Figure P6. Graph of mean monthly rainfall for the Ord region and mean monthly flow for selected rivers in the region

Figure P6. Graph of mean monthly rainfall for the Ord region and mean monthly flow for selected rivers in the region

The Ord River below Lake Argyle receives specific releases from the lake to maintain minimum flows in the lower Ord River and flows year round (Figure P6: Ord River (lower)).

Other rivers in the Ord region exhibit seasonal flow patterns, such as the Keep River, the upper Ord River and tributaries of the Ord River, including the Dunham River, Wilson River and Negri River (Figure P6: Negri River and Ord River (upper)).

Licenced river access

Self-supply licencees access rivers for commercial mining and forestry operations, small scale irrigation, and Stock and domestic purposes. Licenced river access represents about 10% of the total surface water entitlements in the Ord region.

Private irrigation development at Arthur Creek on the Dunham River is the largest entitlement in the region outside of the Ord River Irrigation Area, with approximately 17,000 ML per annum licenced for diversion.

The Keep River is not currently accessed as a water resource. The Western Australian Government plans to develop the resource as part of the Ord River Irrigation Scheme expansion.

The Ord River, downstream of Lake Argyle, is regulated by releases of water from Lake Argyle to maintain flows in the lower Ord River (Figure P6). self-supply licencees access the river for small scale irrigation, industrial and commercial, and Stock and domestic purposes.

Irrigation infrastructure

Ord River Irrigation Area

The Ord River Irrigation Area comprises a canal network that is used to distribute water for irrigated agriculture. About 130 km² is irrigated on the Ivanhoe Plain (to the east and north of the river), with 20 km² irrigated on the Packsaddle Plain (to the west of the river), as shown in Figure P7.

Figure P7. Map of Ord River Irrigation Area

Figure P7. Map of Ord River Irrigation Area

Irrigation water is supplied to the irrigation area from the Ord River at Lake Kununurra via the M1 Channel and the Packsaddle Pump Station. Water supplied to the Ord River Irrigation Area represents almost 90% of the total surface water entitlements in the Ord region.

 

Groundwater

Groundwater resources in the region are not extensively developed. Borefields in localised fractured rock aquifers are used for urban supply to Halls Creek and mining operations in the upper reaches of the Ord region. Sedimentary aquifers adjacent to Lake Kununurra are used to supply the town of Kununurra.

There are sedimentary aquifers underlying the Ord River Irrigation Area, but abstraction does not occur. Rising water tables caused by irrigation activities are monitored in this area.

An expansion of the monitoring bore network and improved understanding of aquifer extent, aquifer properties and groundwater processes is required to exploit groundwater resources in the region.

 

Other water resources

A very small amount of treated effluent from the Kununurra Wastewater Treatment Plant is discharged into the Ord River Irrigation Area via the M1 Channel for use by irrigators. The volume is normally less than 100 ML per annum.