Subregions

The Adelaide and Mount Lofty Ranges region is a highly diverse region. In order to better understand local issues and to work with local communities, the region has been divided into seven subregions that reflect areas that are similar in land form, vegetation types, land uses and social communities.

The subregions are outlined below and further information about each subregion can be found in the strategic plan, which is volume 1 of the Adelaide and Mount Lofty Ranges Natural Resources Management Plan.

Local level planning will target projects towards key issues for each subregion in the Adelaide and Mount Lofty Ranges.

Metropolitan Adelaide

The substantial population and urban sprawl of Adelaide (1.1 million people; Australian Bureau of Statistics 2011) sets the tone for this subregion. The impacts of the population and reserve of social capacity that can contribute to an ecologically sustainable future are important here.

The developed area of the subregion encompasses Port Adelaide and high intensity industries such as defence construction, power generation, cement production and manufacturing, as well as the activities related to any urban area, such as roads and railways, stormwater and waste disposal, recreation, retail, and education and health institutions. Areas of agriculture and horticulture serve local markets and those further afield.

The space remaining for natural resources is limited and the subregion contains a mere 3% of its pre-European vegetation.

Some of the remaining land-based vegetation survives along watercourses, most of which are heavily impacted by upstream rural practices, which contribute nutrients and eroded soil, and downstream urban practices, which contribute high volumes of water often contaminated by nutrients and heavy metals.

Groundwater resources contribute to the horticultural and industrial practices of this low-rainfall area and water-conserving activities, such as wastewater recycling and stormwater retention, are being taken up more and more.

Northern Coast and Plains

This most northwestern part of the region, with topography of low relief in its gently undulating plains and floodplains, is particularly vulnerable to the impacts of climate change. Its major towns: Gawler, Roseworthy, Mallala, Two Wells and Virginia are the focus of urban and industrial development, which could place further stress on its environmental assets. Gawler has significant riparian assets; Roseworthy is a major grain-holding centre and has a campus of the University of Adelaide. Other centres support surrounding farming and horticultural pursuits.

Industry plays a significant environmental role in parts of the region. For example, the salt fields at Dry Creek, along with constructed wetlands, support impressive visitation by migratory bird species, some of which are of international significance, and bring in tourism by bird watchers.

Significant vegetation types include coastal and samphire shrubland, mangrove forest, and diverse mallee and shrubland on the plains. Coastal vegetation, especially in small areas, is a refuge for site specific flora and fauna but is threatened by human development and recreation. A number of plant communities are threatened, as are certain species of plants and animals.

The surface water resources lie in the Lower Light and Gawler rivers. The Light is an unregulated ephemeral river; the much more substantial Gawler River still has variable flows and terminates at Buckland Park Lake and on extensive tidal flats. Water quality in the Barker Inlet–Port River estuary complex has improved since 2000 with the decommissioning of the Port Adelaide Wastewater Treatment Plant and other initiatives including the construction of extensive wetlands to treat stormwater.

Groundwater supports industries, most notably horticulture, and managed aquifer recharge is practised. Longstanding cones of depression have stabilised in recent years with improved water extraction practices.

Northern Hills

Rural industry of significance to the state features in this subregion. The Barossa Valley is a famous wine region, which, with related activities, supports a high employment level; forestry around Mount Crawford is complemented by substantial areas of cropping and grazing; and commuters are moving into the area to enjoy a rural lifestyle.

In the varied topography, grassland and grassy woodland once reigned but were disproportionately cleared and now are still not recognised for their intrinsic worth. Further south, heathy woodland was logged but a significant area remains particularly in the South Para connected area where the Heath Goanna finds some protection.

The watercourses of the Light and North Para rivers are naturally ephemeral but have been reduced by use for stock and irrigation in the south. Flows in the South Para River have been heavily impacted by water storage dams, which provide for northern Adelaide and the lower mid-north, and by farm dams. Flow may be reduced by as much as 60% during the low rainfall period of November–March and the catchment is now prescribed. Irrigation water in the Barossa comes from surface water, groundwater, the River Murray (all prescribed) and recycled water.

Central Hills

The Central Hills, above Adelaide, consist of the landforms of hills face and foothills, central ranges, eastern ranges and escarpment. The towns support dairy farming, orchards, market gardens, viticulture, cattle farming and rural lifestyle blocks. Most of the subregion lies within the Mount Lofty Ranges watershed which supplies about 60% of Adelaide’s water. Significant watercourses are the Torrens and Onkaparinga rivers.

This higher rainfall area once boasted a complex mosaic of vegetation groups with forest, big gum woodland, heathland, grassy woodland and riparian vegetation. Some systems are stable but two landscapes have been identified as priorities for restoration, based on declining woodland birds: lower rainfall grassy ecosystems and closed shrubland ecosystems. Several vegetation communities and plant species are also declining.

Willunga Basin

The gentle hills and plains of the Willunga Basin sit beneath the Willunga escarpment and surround the Onkaparinga River and its estuary. The highly modified landscape, cleared mostly for grazing, was once Box Woodland, grassland and sand heath communities, which now remain only along roadsides and in parks and reserves, making up less than 10% of the subregion. Several plant communities, and species, are listed as threatened and the pressure continues from the southward creeping suburbs of Adelaide and lifestyle residents.

The viticulture industry in the McLaren Vale winegrowing area promotes primary production, tourism, lifestyle opportunities and employment. It is supported by good quality groundwater and recycled water from the Willunga Basin Water Company. Groundwater and surface water are prescribed through the McLaren Vale Prescribed Wells Area and managed through the McLaren Vale Water Allocation Plan. The agricultural nature of the area is protected under the Character Preservation (McLaren Vale) Act 2012.

Fleurieu Peninsula

At the southernmost end of the Adelaide and Mount Lofty Ranges region, the Fleurieu Peninsula contains the iconic Fleurieu Swamps and a diverse natural landscape of plateaus, valleys and ranges, hosting natural vegetation communities largely cleared for grazing.

Victor Harbor, the largest urban centre on the Fleurieu Peninsula, has one of the fastest population growth rates in South Australia and highest median age of any local government area, principally driven by ‘sea change’ retirees. However, the overall population of the subregion is low, leaving a small pool from which to source volunteers for a large area with much natural resources management work to be done. Closed shrubland and lower rainfall grassy woodland are in decline, and several plant communities, and flora and fauna species, are threatened.

Local watercourses, such as the Hindmarsh, Inman and Myponga rivers, are used for irrigation and stock watering; the area is prescribed as part of the Western Mount Lofty Ranges Prescribed Water Resources Area.

Marine

The 41% of the Adelaide and Mount Lofty Ranges region that is a marine environment supports marine flora and fauna in intertidal habitats, marine reefs, extensive seagrass meadows in various states of health, soft bottom systems and deep water habitats. It also supports commercial and recreational fishing, the state’s major port and its attendant activities, and tourism.

The subregion lies in both Gulf St Vincent and the more exposed waters of Backstairs Passage.

Natural Resources Adelaide and Mount Lofty Ranges