Kimberley

The Kimberley subegion of the Western Australian Rangelands is 424,517 square kilometres in size and is the State’s most northern subregion. The coastline faces the Indian Ocean to the west and the Timor Sea to the north. It is bordered by the Pilbara subegion to the south and the Northern Territory to the east.

According to the Australian Bureau of Statistics, 36,562 people lived in the Kimberley in 2011.

History and Economy

Aboriginal people have inhabited the subregion for at least the past 40,000 years. The Kimberley environment holds great cultural significance for Aboriginal people. The Kimberley was first explored by non-indigenous people in the late 1800s and during this time pastoralists from across Australia declared land and started to move cattle into the region. The first stations in the region were settled along the major river systems of the Ord and Fitzroy Rivers. Gold was found in Halls Creek in 1885.

The subregion has a diverse regional economy; mining, tourism, agriculture, aquaculture, fishing and retail are major contributors to the regions’ economic output. Today the major towns of the Kimberley are Broome and Kununurra. Broome was initially known for pearling however tourism is currently its major industry, while Kununurra’s economy is driven by a mixture of agriculture, mining and tourism.

Mining is by far the largest revenue earner and exploration activities include searching for diamonds, gold, iron ore, nickel, off-shore gas and crude oil. Tourism provides the second greatest contribution to the local economy.

The major agricultural activities of the Kimberley include horticulture (market gardening and fruit production), pastoralism and agriculture. Agricultural activities, horticulture and sugar cane provide substantial economic input into the region, especially in the Ord River Irrigation Area (ORIA). Pastoralism is iconic and a way of life in the Kimberley and continues to make a significant contribution to the local economy.

Natural Environment

Climate

The Kimberley has a strongly arid to semi-arid monsoonal climate that is characteristically hot and wet in the summer (wet season) and warm and dry in the winter (dry season). The months of May to August are relatively cool with average temperatures between 16°C and 32°C. In the remaining months maximum temperatures exceed 35°C and in October-November often exceed 38°C. Annual average rainfall ranges from 1,500 mm in the north-west coastal areas to less than 350 mm on the southern perimeter and is generally confined to the six-month ‘wet’ period November to April, with January and February being the wettest months. It has a pronounced north-south rainfall gradient, so that southern parts of the zone are semi-arid, with a shorter growing season, less reliable rainfall and higher annual temperature range than the northern parts.

Rivers

The Kimberley includes over one hundred rivers and many more creeks and streams which flow north or west, forming the Timor Sea drainage division.They exhibit highly seasonal flow conditions as a result of being located at the southern edge of the global monsoon system, where intense and widespread rainfall results in flood flows during summer.The largest river in terms of flow in the Kimberley, and in WA, is the Fitzroy – which has floodplains several kilometres wide. The Ord is the second largest river in WA and one of the most well known. Water from the Ord River is used in the economically important Ord River Irrigation Area.

Wetlands

There are 23 wetlands (including rivers) of national importance and four Ramsar listed wetlands within the Kimberley and nine on the Register of National Estate. The four declared Ramsar sites (listed as International wetlands of significance under a global treaty) in the Kimberley are Lake Kununurra and Lake Argyle, the Ord River Floodplain, Roebuck Bay and Eighty Mile Beach. Paruku (Lake Gregory) also satisfies criteria for listing as a Ramsar site.

Coastline

The Kimberley coast is approximately 2,500 kilometres in length and contains more than 3,000 islands. It’s unique from an Australian perspective due to its large tidal range, with a movement of up to 12 metres driving coastal processes. This coast is one of the most contorted of anywhere on the Australian coastline and its geological, biological and anthropogenic history is unique.

Flora and Fauna

Biodiversity in this subregion is unique and highly varied. It supports a diverse and spectacular flora of more than 2000 plant species and the fauna is unique and rich in species diversity, including many threatened and endangered species.

Vegetation

Vegetation is generally characterised as tropical savanna, although there is considerable variation throughout, determined by rainfall, topography and soils. The most extensive vegetation is eucalypt woodland and open woodland, but there are also areas of hummock grassland, tussock grassland and acacia open woodland. The ground layer is almost always dominated by grasses, with grazing mostly based on native, perennial tussock grasses and in some instances introduced buffel and birdwood grasses.

IBRA Subregions

The Kimberley contains five IBRA sub-regions: Central Kimberley, Dampierland, Northern Kimberley, Ord Victoria Plains and Victoria Bonaparte. To read more about IBRA subregions, and to access the Australian Government’s detailed descriptions of each, visit the Department of the Environment and Energy website.