South East Queensland: Physical information
General description
Area: Approximately 21,331 km² (provided by A Peacock [Seqwater], pers. comm., 27 November 2013)
Population: Approximately 3.2 million (Australian Bureau of Statistics [ABS] 2011)
The South East Queensland region is located on the southeast coast of Queensland (Figure C1). It is home to 72% of Queensland's population (ABS 2011).
Figure C1 The South East Queensland region within Australia
The South East Queensland region shown in Figure C2 is bounded by the New South Wales–Queensland State border in the south, the Pacific Ocean in the east, the Great Dividing Range in the west and the headwaters of the Brisbane River in the north. Mountains exist along the western and southern edges of the region, while coastal plains dominate the east. It contains several large rivers that discharge into the Pacific Ocean.
Figure C2 Contextual map of the South East Queensland region
Region definition
The South East Queensland region covered in this report consists of three surface water basins: Gold Coast, Logan Basin and Moreton. The region is physically defined by the surface water catchments and includes all water resources within or beneath the physical area as shown in Figure C2.
The region report includes:
- water in surface water storages
- water from the Lockyer Valley alluvial aquifer and Cressbrook Creek alluvial aquifer
- water within urban infrastructure associated with SEQ Water Grid, off-grid local water supply schemes, wastewater systems and recycled water systems throughout the region
- desalinated water entering the region
- recycled water from the Western Corridor Recycled Water Scheme (WCRWS).
The region report excludes:
- water held in off-channel water storages such as farm dams and private commercial water storages used to harvest runoff or collect rain water
- water held in the landscape such as soil moisture
- water held in wetlands that are not connected to rivers
- water held in the Great Artesian Basin (GAB).
Land use
The South East Queensland region is the most densely populated area of Queensland. The resident population of major cities, towns and urban centres within the region is shown in Table C1.
| City/town | Population |
| Brisbane | 1,089,879 |
| City of Gold Coast | 515,202 |
| Moreton Bay | 390,051 |
| Logan | 287,474 |
| Ipswich | 172,200 |
| Redland City | 143,711 |
| Total | 2,598,517 |
Source: ABS 2011
A number of small towns are interspersed throughout the rest of the South East Queensland region including Beaudesert, Blackbutt, Esk, Gatton, Kilcoy, Kooralbyn, Laidley and Yarraman. Figure C3 shows the distribution of land use in the South East Queensland region. Land use activities that are major water users in the region include irrigated agriculture and urban (Queensland Government Department of Natural Resources, Mines and Water 2005, 2006a, 2006b; Queensland Government Department of Natural Resources and Water 2007).
Figure C3 Land use in the South East Queensland region
Source: Interpreted from Australian Government Department of Agriculture 2015.
Significant aquatic ecosystems
Wetland systems of international and national importance are located in the South East Queensland region (Figure C4). Further information can be found on Wetlandinfo (Queensland Government Department of Environment and Heritage Protection 2016). The wetlands of Moreton Bay adjacent to the region and affected by outflows from the region are listed in the international Ramsar Convention of Wetlands (Australian Government Department of the Environment 2016a, 2016b). They cover in excess of 11,000 km², most of which are on coastal islands or near shore marine areas. The habitat ranges from perched freshwater lakes and sedge swamps on the offshore sand islands to intertidal mudflats, marshes, sandflats and mangroves next to the bay's islands and mainlands.
Figure C4 Nationally important wetlands and Ramsar wetlands in the South East Queensland region
Significant Indigenous cultural places and practices
Prior to European settlement, a reasonably high number of Indigenous people lived in the South East Queensland region (Jabree Ltd 2013). It is estimated that the watershed areas alone of the Logan, Albert, Coomera and Nerang rivers contained 1,500 to 2,000 Indigenous communities with fairly dense settlements in terms of Aboriginal populations.
The Indigenous people believe that spiritually they are part of the landscape, of which they emphasize four separate elements: landscape boundaries, pathways, biodiversity matters and important sites/areas (Choy et al. 2011). These four elements relate in different ways to water within South East Queensland.
Natural boundaries include creeks, rivers, channels, mountain ranges and invented boundaries created through myth and stories for community safety purposes (including forbidden areas, dangerous swamps, lakes and snake habitats).
The Indigenous people used pathways formed by passages of land and water to move through the landscapes. Usually valleys, wildlife corridors, beaches, waterways, channels, currents and tides are recognised as pathways of importance to them.
The Indigenous people had three main ways of identifying biodiversity in the regional landscape. These were interpretation of the 'bush calendar' (including animal behaviour, flowering seasons and weather), interpretation of indicators and warning signs (using fauna) and presence and absence of totemic species and habitats. Using these techniques, they developed an acute sense of identifying even small biodiversity changes. In order to track the changes, they use a 'totem' which is a typical animal or plant species that is in some way connected to a clan group, family or individual. This builds up a strong spiritual connection between the regional landscape and each individual. It is believed that the totem can serve as an indicator of the environmental changes (Choy et al. 2011).
Water resources
Most of the region's water supply comes from surface water. Groundwater use is limited to various alluvial aquifers located along river valleys. Desalinated and recycled water resources within the region have been developed in recent years.
Based on the water use in relation to total inflows, available water resources and sustainable yield in the Brisbane water supply area, the water resource is moderately developed with surface water management plans in place across the entire region (Australian Government National Water Commission 2007).
Groundwater resources within the region are being developed, with GMAs now present across many high-use alluvial aquifers. It is expected that additional GMAs may be introduced as groundwater use is further developed. Agriculture is the main groundwater use within the South East Queensland region.
Water stored within the region's surface water storages is mainly for urban use, although some dams also provide flood mitigation measures. For example, as a flood mitigation measure, Wivenhoe Dam is designed to hold back 1.967 million megalitres of extra water on the top of its 1.165 million megalitres of drinking water storage.
Recycled water and desalinated water supplement the surface and groundwater resources for urban use and power supply within the region.
Surface water
Figure C5 shows mean monthly flow and mean monthly rainfall for the four main rivers within the South East Queensland region: Albert River at Bromfleet (Station 145102B), Bremer River at Walloon (Station 143107A), Brisbane River at Savages Crossing (Station 143001C) and Logan River at Yarrahappini (Station 145014A). Typically, these rivers have flow throughout the year. The seasonal flow characteristics of the four rivers reflect the rainfall pattern of the South East Queensland region where a large proportion of rainfall occurs between November–March. Figure C6 provides the location of the key flow gauging stations along the main rivers within the region.
Figure C5 Mean monthly flow along the rivers and mean monthly rainfall for the South East Queensland region
Figure C6 Key flow gauging stations along the main rivers within the South East Queensland region
Storages
Surface water storages are an important water source for water supply in the South East Queensland region. The storages which are managed by Seqwater, Toowoomba Regional Council and Tarong Energy, are shown in Figure C7. Information on capacities of the storages is available as a downloadable table. The largest storages in the region are Wivenhoe (1,165,238 ML), Somerset (379,849 ML), Hinze (310,730 ML) and North Pine (214,302 ML). Together they represent approximately 84% of the region's storage capacity. Some of the smaller public storages have not been included in the account and it's estimated these comprise less than 1% of the region's total storage capacity.
Figure C7 Surface water storages in the South East Queensland region
Groundwater
The primary source of water for the irrigation-dominated upland valleys of the South East Queensland region (such as the Lockyer Valley) is groundwater extracted from alluvial aquifers. The Lockyer Valley alluvial aquifer overlies the Great Artesian Biasn (GAB) but is not a part of it, and is managed as a separate resource under Moreton water resource plan (WRP). In the south, groundwater use is minor. In certain areas, groundwater throughout the region is sourced from local confined aquifers for agricultural and domestic uses. Shallow bores are used to access groundwater for garden-watering on the coastal plain.
The region's groundwater layers can be categorised into the following types:
- Palaeozoic age basement rocks
- Early–Middle Triassic age metasedimentary rocks
- Permo–Triassic age intrusive rocks
- Mesozoic age sedimentary basins
- Mesozoic age volcanics
- Tertiary age sedimentary basin sediments
- Tertiary age basalts
- Quaternary age valley alluvial fills.
The GAB (Queensland Government Department of Natural Resources and Mines 2016), one of the world's largest groundwater resources with an estimated total stored volume of 65,000 million megalitres, underlies 22% of Australia's land mass including a large portion of Queensland. The groundwater resources in the GAB in Queensland are managed under the Great Artesian Basin Plan 2006 (Queensland Government Office of the Queensland Parliamentary Counsel 2015a) and the Great Artesian Basin Resource Operations Plan 2007 (Queensland Government Department of Natural Resources and Mines 2016). This divides the Queensland component of the GAB into 25 management areas. One of these areas, the Clarence-Moreton management area is located partially within the South East Queensland region and is made up of Walloon Coal Measures, Marburg Sandstone and Helidon Sandstone. The Clarence–Moreton management area is 400 km in length and 125 km in width; it extends from Toowoomba in the west to Darr Creek in the northwest, Esk in the north, Ipswich in the east and through to Rathdowney in the south (Queensland Government Department of Natural Resources and Mines 2016). It underlies the Lockyer Valley, Bremer River Valley and Teviot Brook catchment.
Desalinated water
Desalinated water is blended with other Gold Coast water supplies and joins the South East Queensland Water Grid. The region's storages have been full or near full since December 2010, hence the plant has been operating in 'hot standby' mode since that time to minimise operating costs. Under this mode, the plant produces 25 ML/day, twice a week. This small amount of production is necessary to keep the membranes wet and the water in the pipes fresh while retaining the capacity to increase production to 44ML/day within 24 hours and 133ML/day within 48 hours. The plant may also be called on if there are interruptions to supply in other parts of the SEQ Water Grid.
Other water resources and systems
Urban water system
Major urban infrastructure within the South East Queensland region are illustrated in maps of Seqwater major assets (Seqwater 2016a).
Potable water is supplied to residents across much of the region. In the heavily populated areas around Brisbane, City of Gold Coast, Logan City and Ipswich, potable water is supplied through the SEQ water grid; however, a number of the region's residents live in communities where the drinking water supplies are not directly connected to the water grid. These communities obtain water from a range of sources including unregulated rivers, groundwater and recycled water with varying levels of security.
The SEQ water grid was established in July 2008 to connect water supplies and treatment facilities across the region. The grid comprises an infrastructure network of treatment facilities and two-way pipes that move water between new and existing sources across the region. It provides the whole of the region with access to more water sources and is both dependent on climatic conditions (surface water storages) and resilient to climatic conditions (desalination and purified recycled water). The network includes more than 600 kilometers of reverse-flow pipelines including the 47 km bi-directional Northern Pipeline Interconnector that moves water from Noosa to Coolangatta in the south.
Key components include 26 major surface water storages, 51 weirs, 37 operational water treatment plants (WTPs), 22 bulk water pump stations, 18 bulk water reservoirs and 14 groundwater bore fields. The roles of water retailers within the South East Queensland region are reported in Table C4 in the Organisations responsible for water management section of 'Administration'.
There is also a water pipeline between Wivenhoe Reservoir and Cressbrook Creek for supplying raw water to Toowoomba Regional Council, if there is any shortage of water.
More information on the South East Queensland region's urban water systems can be found in the Urban water system section of 'Supporting information ' note and in the Australian Water Resources Assessment 2012 (Bureau of Meteorology 2013).
Recycled water
Two main recycled water schemes exist within the South East Queensland region: recycled water treatment plant at Pimpama–Coomera of the City of Gold Coast, and the Western Corridor Recycled Water Scheme (WCRWS) extending from Brisbane's southwest suburbs towrads the city of Ipswich.
Gold Coast residential supply
Class A+ recycled water is supplied to residential (for toilet-flushing and external use) and non-residential (industrial use) in the Pimpama–Coomera area of the City of Gold Coast .
The recycled water treatment plant is part of the Pimpama–Coomera Waterfuture Master Plan.
Power station supply
The WCRWS used to provide purified recycled water to power stations and fertiliser industries and potentially agricultural users. The WCRWS was decommissioned on 31 March 2015 and is now in care and maintenance mode (Parliamentary Committees 2015).
Prior to its decommission in March 2015, the WCRWS formed part of the SEQ Water Grid and the power stations, namely the Swanbank B and Swanbank E power stations (located within the South East Queensland region). The Tarong and Tarong North power stations (located outside the South East Queensland region) were the main customers for the recycled water. Treated effluent from six wastewater treatment plants (WWTPs) was further treated to purify recycled water at three separate advanced water treatment plants (AWTPs) located at Bundamba, Gibson Island and Luggage Point.
When all three AWTPs were operating at capacity, the WCRWS had a capacity of 232 ML/day, subject to the availability of inflowing water from the WWTPs that supply the AWTPs.
Water resources outside the region
The SEQ water grid (SEQ Water Grid Manager 2012) extends beyond the northern and eastern boundaries of the National Water Account's South East Queensland region supplying and sourcing water from both within and outside of the region. As demand in these outside areas is generally less than the available supply, some of the surplus is transferred into the South East Queensland region via the SEQ water grid. These are considered to be inter-region transfers and include water transferred from the Mary Basin north of the region, and groundwater transferred from North Stradbroke Island and Bribie Island.
Farm dams
The Queensland Government Department of Environment and Resource Management (DERM) has indicated that there are approximately 1,700 farm dams within the South East Queensland region with a combined estimated storage volume of 59,080 ML.
The information from 2010 has been extracted from the Large Referable Farm Dam Identification Program dataset (Queensland Government Department of Energy and Water Supply) which identified farm dams greater than 0.25 ha in area using Landsat 30 m imagery. Some dams may have been omitted during this selection process due to the remote sensing methods used. The data is not intended as a complete count of farm dams but is an indication of the number of larger farm dams within the South East Queensland region.