National Water Account 2017

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Key findings

Climate and water

Water Accounting Statements

Supporting information

Region description

Reference information

Adelaide: Geographic Information

General description

Area: 5,350 km²

Population: Approximately 1.3 million (Australian Bureau of Statistics [ABS] 2016).

The Adelaide region is located in the southeast of South Australia, on the east coast of the Gulf St Vincent. It extends from the Barossa Valley in the north to the Fleurieu Peninsula in the south, and includes metropolitan Adelaide, the Northern Adelaide Plains, and the Western Mount Lofty Ranges (Figure R1). The terrain ranges from flat plains near the coast to steep hills in the east and south.

Figure R1 Contextual and catchment boundary map of the Adelaide region

Region definition

The Adelaide region is physically defined by the hydrological boundaries of the following catchment areas, from north to south (refer Figure R1):

• Gawler, North Para, and South Para rivers and tributaries, including the South Para reservoir, which flow west from the northern Mount Lofty Ranges to the Gulf St Vincent (2,095 km²)
• River Torrens, which flows from the Mount Lofty Ranges through Kangaroo Creek Reservoir to Adelaide and then to the Gulf St Vincent and the Little Para River (1,135 km²)
• Onkaparinga River, which flows west from the southern Mount Lofty Ranges to Hahndorf, then through Mount Bold Reservoir to the Gulf St Vincent (930 km²)
• Myponga River, which flows into the Myponga Reservoir and then southwest to the Gulf St Vincent (153 km²)
• Fleurieu Peninsula, includes several smaller rivers, such as the Bungala and Yankalilla, that flow west into the Gulf St Vincent and the Hindmarsh and Inman rivers that flow southeast into the Southern Ocean (1,037 km²).

The region includes water stored in and transactions related to:

• surface water storages in the region
• rivers within the region
• water held in storages, pipes, and infrastructure as part of urban water supply and wastewater systems
• groundwater aquifers beneath the region
• irrigation schemes within the region.

The region excludes water stored in and transactions related to:

• water held in farm dams, private commercial water storages and rainwater tanks used to harvest runoff, floodwater or collect rainwater. Farm dams are excluded because these constitute water that is already abstracted and is no longer available for sharing
• water held in wetlands that are not connected to rivers and estuaries
• water held in the landscape, such as soil moisture.

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

Land use

The Adelaide region hosts a diverse range of land uses. Urban land use makes up 16% of land use (Figure R2) with major population centres including: 

• Adelaide metropolitan area (including Gawler)—1,295,714 (ABS 2016a)
• Barossa region—35,496 (ABS 2016b)
• Fleurieu Peninsula—50,397 (ABS 2016c).¹

^{1. The estimate for the Fleurieu Peninsula above includes population estimates for Kangaroo Island, which is not part of the Adelaide region; however, this number is small in comparison to the total population for the Fleurieu Peninsula area.}

Figure R2 Land use in the Adelaide region

The major land users (more than 50% by area) in the Adelaide region are from key agricultural industries (grazing, dryland, and irrigated agriculture) including wine production, beef and dairy cattle, vegetable growing, and fruit orchards (Figure R2).  Three irrigation schemes operate in the region to supplement existing water resources for the irrigated agriculture industry (refer to Water systems). Conservation and natural environments make up 13% of land use throughout the Adelaide region, while forestry and mining account for only minor uses. 

Significant aquatic ecosystems

The region contains The Coorong and Lakes Alexandrina and Albert Wetland, which is Ramsar listed. The region is also home to several nationally significant wetlands, listed in the Directory of Important Wetlands in Australia as shown in Figure R3.

Figure R3 Significant wetlands in the Adelaide region

Water resources

South Australia is the driest State in Australia. Given the low rainfall conditions in the region, Adelaide's water supply cannot solely rely on its natural surface water and groundwater reserves alone and has developed several different sources for providing water security. To meet demand, Adelaide has diversified its water sources to include:

• surface water including watercourses
• groundwater including managed aquifer recharge
• local catchment harvesting through farm dams
• River Murray pipeline transfer
• recycled stormwater and wastewater
• desalinated water produced at Port Stanvac Desalination Plant.

Surface water and groundwater resources are well developed, and recycled stormwater and wastewater are used increasingly for agricultural and municipal irrigation, and for industrial purposes.

The Adelaide Desalination Plant provides an additional climate resilient water source to the surface water generated within the Adelaide region or transferred from the River Murray (see the Desalinated water section for more information).

Surface water

The Adelaide region's surface water resources include the drainage basins described in the General description.

Rivers

Most of the flow within the region's drainage basins usually occurs from June–October, reflecting the rainfall and potential evapotranspiration pattern of the region, where mean monthly rainfall is higher in May–October and potential evapotranspiration is low. Figure R4 shows the location of representative flow gauging stations on unregulated reaches of the North Para (A5050502), Onkaparinga (A5030504), and Myponga (A5020502) rivers. Flow data collected at these stations were used to represent the seasonal flow patterns along these rivers in Figure R5.

Figure R4 Selected flow gauging stations on the North Para, Onkaparinga and Myponga rivers within the Adelaide region

Figure R5 Mean monthly flows along the North Para, Onkaparinga and Myponga rivers and mean monthly rainfall for the Adelaide region

Storages

Surface water storages and weirs operated by SA Water and used for urban water supply are detailed in Figure R6.

Figure R6 Surface water storages and weirs in the Adelaide region 

Further information on the Adelaide region's storages, including current levels and volumes for reservoirs, is given on the Bureau of Meteorology's Water storage website. Note that the volumes reported on the Water storage website exclude the dead storage volumes.

Groundwater

Groundwater is an important water resource in the Adelaide region for both irrigation and stock and domestic supply. The major groundwater resources are described in Table R1.

The location of each groundwater management area in the Adelaide region is shown in Figure C10 in 'Water management'.

An example subsection of the Northern Adelaide Plains aquifers is shown in Figure R7.

Figure R7 Groundwater system within the Adelaide region

Groundwater generally flows west from the higher rainfall recharge areas in the Western Mount Lofty Ranges towards the St Vincent Basin (Stewart, Banks and Wilson 2009). Lateral inflow is the main mechanism for recharge of the coastal aquifers.

Desalinated water

The Adelaide Desalination Plant, located at Port Stanvac (Figure R8), treats sea water taken from the Gulf St Vincent, providing an additional, climate-independent water source. Desalinated water is mixed with water treated at the Happy Valley Water Treatment Plant before entering the Happy Valley distribution network. The completed North South Interconnection System project enables SA Water to deliver this desalinated water to customers in both Adelaide's northern and southern suburbs.  

The Adelaide Desalination Plant is able to produce up to 100,000 ML/year of water, which is about half of metropolitan Adelaide's annual water demand; however, the plant's production levels will vary depending on customer demand, impacts on other water resources, and emergency responses (i.e., in response to flood events). The use of the desalination plant is balanced with volumes stored in surface water storages and volumes received under SA Water's River Murray licence to ensure customer demand is met in a sustainable and cost-effective manner.

There are also more than 25 privately and publicly owned desalination plants with an individual capacity greater than 1.8 ML/year in the region. These desalination plants are typically used to improve groundwater, wastewater, and mains water quality on a small scale to a standard suitable for irrigation, industry, and medical purposes.

Recycled water

Recycling of wastewater is increasingly significant to the Adelaide region. There are several wastewater recycling schemes outlined on the South Australian Department of Environment, Water and Natural Resources website. Approximately 30% of the wastewater treated at SA Water's wastewater treatment plants is used in recycled water applications (Office for Water Security 2010) including agricultural, viticultural, municipal, parks, and recreational purposes. A large proportion of the recycled water is provided to Virginia Pipeline Scheme and Willunga Basin Water Company from Bolivar, Christies' Beach, and Aldinga treatment plants. Under the Aldinga Aquifer Storage and Recovery Scheme, recycled water is supplied from the Christies Beach treatment plant and injected to the Port Willunga Formation aquifer as managed aquifer recharge.

In addition to SA Water's  wastewater treatment plants, community wastewater management schemes are another source of recycled water (refer Community Wastewater Management Schemes for further information). 

Stormwater harvesting

Stormwater harvesting (collection, treatment, and use of urban runoff) is of increasing importance to the Adelaide region and forms an integral part of the South Australian Government's water security strategy (Office for Water Security 2010). 

There are currently eight stormwater harvesting and reuse projects underway in the Adelaide region, with the collective capacity to harvest approximately 8,000 ML of stormwater annually. The projects involve treating stormwater through constructed wetlands and storage in aquifers. Treated stormwater is generally used for irrigated agriculture, and irrigation of parks and ovals, as well as third-pipe supply to industrial, commercial, and residential customers. For further information refer to the Department of Environment, Water and Natural Resources website.

Mine, construction, and quarry dewatering

Mine dewatering occurs in the Adelaide region to facilitate mining, quarrying, and construction activities. Depending on water quality, the water is stored in above-ground storages, discharged into nearby watercourses or aquifers, or applied to the landscape. For example, Penrice dewaters the Quarry in Angaston within the Barossa Prescribed Water Resources Area  (Golder Associates 2008).

Water systems

Urban water system

The urban water system includes water treatment plants and wastewater treatment plants, pipes and tanks, owned and operated by SA Water. This urban water system infrastructure, including the urban water supply area, treatment plants, the main desalination plant, and major pipes that are used to service the Adelaide region's urban water needs are depicted in Figure R8.

Figure R8 Urban water system infrastructure within the Adelaide metropolitan area

Key urban infrastructure shown in Figure R8 in the Adelaide region includes:

• the metropolitan water supply system which includes six water treatment plants to provide potable water for urban consumption, including desalinated water.

• the metropolitan wastewater system, which includes six wastewater treatment plants which collect and treat wastewater, providing recycled water and disposing of unused treated wastewater.

Urban users in the Adelaide region are also supplied by several water treatment plants outside the Adelaide metropolitan boundaries, however these have not been included within the Account.

More information about the Adelaide urban water system can be found at the SA Water website.

Irrigation schemes

Three major irrigation schemes operate in the Adelaide region.

Virginia Pipeline Scheme

The Virginia Pipeline Scheme is a public-private partnership between SA Water and Trility Pty Ltd. It services the Virginia and Angle Vale districts in the north of the Adelaide region, providing water to irrigators through a large (>120 km) network of pipes. Recycled water from the Bolivar Waste Water Treatment Plant (WWTP) is provided for the irrigation of 20 different crops, including fresh vegetables.

Barossa Infrastructure Limited

Barossa Infrastructure Limited services the Barossa Valley, providing water to irrigators for viticulture through a network of approximately 189 km of underground pipes. River Murray water is the primary water source, supplied via the Mannum–Adelaide pipeline and, if required, via the Swan Reach–Stockwell pipeline in case of need. Recycled water supplements this water, received from the Nuriootpa CWMS. 

Willunga Basin Water Company

The Willunga Basin Water Company is a reclaimed water scheme owned and operated by its users. It services the McLaren Vale region providing recycled water to irrigators through a network of approximately 120 km of pipe. This is predominantly irrigation water for viticulture, but is also used for irrigation of fruit trees, nut crops, and flowers. Recycled water from the Christies Beach wastewater treatment plant is the primary source of water, including water injected to groundwater as part of the Aldinga Aquifer Storage and Recovery Scheme. Recycled water is also received from the Aldinga wastewater treatment plant and the Willunga community wastewater management schemes.

Community Wastewater Management Schemes

These schemes harvest water from household septic systems and are typically operated by local councils. They provide recycled water for irrigation of vines and recreation facilities, including that supplied to the region's irrigation schemes. Some of the community wastewater management schemes operating in the Adelaide region are presented in Table R2.

Farm dams

Farm dams refer to landscape catchment storages used to harvest runoff, floodwater, or collected rainwater. They are an important water resource in the region; however, water held in farm dams is considered to be taken from the shared pool of water resources and, as such, is not included as part of the region's water assets (see Region definition).

The Adelaide region has in excess of 15,000 farm dams holding more than 39,700 ML of water when full. On average, farm dams harvest around 10% of annual runoff, although on a seasonal basis this can be more than 70% in some catchments during the summer and autumn months. Water held in and abstracted from farm dams is used for a combination of purposes including industrial, irrigation, and stock and domestic purposes.