Ord
Physical information

General description

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

The Ord region is located in the East Kimberley region of Australia, as shown in Figure P1. The region overlaps the border between Western Australia and the Northern Territory. About 75% of the region is 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 catchments: those of the Ord River and the Keep River. This is shown in Figure P2.


Figure P2. Contextual map of the Ord region
Figure P2. Contextual map of the Ord region
Ord River catchment

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

The 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 catchment includes the King River which supplies water to the town of Wyndham.

Keep River catchment

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

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

Description of the region

The Ord region is physically defined by the boundaries of the Ord River, Keep River and King River catchments 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
  • rivers within the region
  • groundwater aquifers beneath the region.

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

  • water held in pipes and infrastructure of the urban water system
  • off-channel water storages and rainwater tanks, 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 rivers.

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

Land use

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

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

Populations are based on the Kimberley Statistical Division: Ord subdivision (Australian Bureau of Statistics, 2011). 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 (Australian Bureau of Agricultural and Resource Economics and Sciences, 2010).


Table P1. Land use in the Ord region

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

Most irrigated agriculture occurs in the Ord River Irrigation Area and land adjacent to the Ord River that has access to water for irrigation. All of this land is downstream of Lake Argyle. 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.


Figure P3. Map of land use in the Ord region
Figure P3. Map of land use in the Ord region

There are over 4,000 km² of parks and reserves in the Ord region, including:

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:

These are displayed 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 groups, particularly the Miriuwung and Gajerrong peoples. Further information is available in the study of Aboriginal Cultural Values of the Ord River and Wetlands (2003).

Water resources

There are five major surface water resources in the Ord region:

  • Lake Argyle
  • Lake Kununurra
  • Arthur Creek Dam, on a tributary of the Dunham River. For water supply to Tropical Forestry Services Corporation Limited
  • the Ord River channel, downstream of Lake Kununurra
  • Moochalabra Dam, on the King River. For water supply to Wyndham.

There are two groundwater resources in the Ord region:

  • aquifers of Kununurra and
  • aquifers of Halls Creek.

Tributaries of the Ord River, both upstream and downstream of Lake Argyle, provide additional water resources.

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 licencees (5%).

Groundwater resources in the region are primarily used for mine dewatering and operations (95%) and 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 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

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 irrigation
Releases for environmental water provision
Mining
Urban supply
Lake Kununurra
(or Kununurra Diversion Dam)
100,825
87,000
Directly receives releases from Lake Argyle
Supplies Ord River Irrigation Area
Supplies adjacent self-supply irrigators
Arthur Creek Dam
65,000
Unknown
Supplies private company Tropical Forestry Services
Moochalabra Dam
2,023
175
Town supply for Wyndham
Total
10,923,678
411,175

 

Lake Argyle is located on the Ord River. Downstream of Lake Argyle is Lake Kununurra (or Kununurra Diversion Dam). The Dunham River flows into the Ord River just downstream of Lake Kununurra. Arthur Creek Dam is located on a tributary of the Dunham River.

Moochalabra Dam is located on the King River, west of the Ord.

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 water under licence from Lake Argyle if their private water storages provide insufficient water. 

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.

Arthur Creek Dam

Arthur Creek Dam, located on the Dunham River, is a large private storage. The storage is used for self-supply irrigation.

Moochalabra Dam

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

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. Upstream of Lake Argyle, flows are very low or cease to flow during the dry season between April and October. The Ord River below Lake Argyle receives specific releases to maintain minimum flows in the lower Ord River. Here water flows year round (Figure P6).


Figure P6. Mean monthly flow and rainfall for Ord region
Figure P6. Mean monthly flow and rainfall for Ord region


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.

Licensed river access

Self-supply licencees access rivers for commercial mining and forestry operations, small scale irrigation, and stock and domestic purposes. Licensed 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 licensed 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). This is 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.

Groundwater monitoring occurs in sedimentary aquifers underlying the Ord River Irrigation Area. The focus of the groundwater monitoring is the rising water table caused by irrigation activities. No groundwater is used for irrigation.

An expansion of the monitoring bore network and improved understanding of aquifer extent, aquifer properties and groundwater processes would be required if groundwater resources in the region were to be developed.

Other water resources and distribution systems

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.