South East Queensland
Physical information

Area: 21,540 km² (Source: Healthy Waterways website)

Population: 2,614,000 (local government areas: Brisbane, Gold Coast, Ipswich, Lockyer Valley, Logan, Moreton Bay, Redland, Scenic Rim and Somerset from Australian Bureau of Statistics 2010)

The South East Queensland (SEQ) region is located on the southeast coast of Queensland (Figure P1) and is physically defined by the following hydrological boundaries:

• Moreton Catchment, including the Pine Rivers and Brisbane River
• Logan Basin Catchment, including the Logan River
• Gold Coast Catchment, including the Nerang River.

This region does not include Stradbroke Island, Bribie Island, the Sunshine Coast or Toowoomba.

The SEQ region spreads from the New South Wales–Queensland state border in the south, the Pacific Ocean in the east, the top of the Great Dividing Range in the west and the headwaters of the Brisbane River in the north (Figure P2). Mountains exist along the west and southern edge of the SEQ region with coastal plains in the east. The region contains several large, coastal discharging rivers. The major catchments within the region are listed in Table P1.

Figure P1. Location map of the South East Queensland region within Australia


Figure P2. Contextual map of the South East Queensland region

Table P1. Major catchments within the South East Queensland region

Major catchment	Catchment area  (km2)	Water resource plan (WRP) area
Coomera River	440	Gold Coast
Nerang River	501
Pimpama River	175
Tallebudgera and Currumbin Creek	158
Albert River	786	Logan Basin
Logan River	3,077
Tingalpa Creek, Redlands Creek and Eprapah Creek	281
Brisbane River	14,040	Moreton
Caboolture River	468
North and South Pine rivers	825
Pumicestone Creek	789

Source: Healthy waterways website

The SEQ region is physically defined in the section above, and includes all water resources within or beneath the physical area.

The SEQ region includes water stored in:

• surface water storages
• the Lockyer Valley groundwater management area (GMA) alluvial aquifer beneath the SEQ region
• urban infrastructure associated with SEQ Water Grid, off-grid local water supply systems, wastewater systems and recycled water systems throughout the region
  
• desalinated water entering the region
• recycled water from the Western Corridor Recycled Water Scheme.

The SEQ region 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, and water held in wetlands that are not connected to rivers
• water held in the Great Artesian Basin.
  

The major cities, towns and urban centres in the SEQ region are shown in Table P2.

Table P2. Major population centres within the South East Queensland region

Locality	Population
Brisbane	1,090,000
Gold Coast	514,000
Moreton Bay	390,000
Logan City	288,000
Ipswich	172,000
Redland City	144,000

Source: Australian Bureau of Statistics 2010, showing 30 June 2011 populations

A number of small towns are interspersed throughout the rest of the SEQ region including Aratula, Beaudesert, Benarkin, Blackbutt, Boonah, Canungra, Esk, Fernvale, Gatton, Jimna, Kalbar, Kilcoy, Kooralbyn, Laidley, Linville, Lockyer, Lowood, Preston, Rathdowney, Somerset, Toogoolawah, Warrill View and Yarraman.

South East Queensland is the most densely populated area of Queensland. Water use is predominately urban around Brisbane and the Gold Coast, with irrigated agriculture being a major water user within the rural portion of the region.

Table P3 and Figure P3 show that grazing and conservation are the largest land uses in the SEQ region and that water intensive land use in the region is predominantly irrigated agriculture and urban (Department of Natural Resources & Mines 2005; Department of Natural Resources, Mines & Water 2006a; Department of Natural Resources, Mines & Water 2006b). Major agricultural products include dairy, fodder crops, cereal and horticultural crops.

Figure P3. Map of land use in the South East Queensland region

Table P3. Land use in the South East Queensland region

Land use	Area (km2)	Area (%)
Conservation and natural environments	3,267	16
Grazing	11,777	56
Forestry	1,541	7
Dryland agriculture	233	1
Irrigated agriculture	639	3
Urban	2,402	11
Other intensive uses	795	4
Mining	3	0
Water	443	2
Total SEQ region	21,100	100

Source: Australian Bureau of Rural Sciences 2010

The SEQ region contains 12 nationally important wetlands, listed in the Directory of Important Wetlands in Australia. Further information can also be found on the Queensland Government Wetland information website.

The wetlands of Moreton Bay, adjacent to the region and effected by outflows from the region, are listed as Ramsar wetlands. They cover in excess of 11,000 km², most of which is 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 the mainland.

The SEQ region includes the following wetlands from the Directory of Important Wetlands in Australia:

• Conondale Range Aggregation
• Dalrymple and Blackfellow creeks
• Greenbank Army Training Area
• Moreton Bay Aggregation (only the freshwater component is located within the SEQ region)
• Carbrook Wetlands Aggregation
• Karawatha Forest Park Wetlands
• Upper Coomera River
• Pine River and Hays Inlet (only the freshwater component is located within the SEQ region)
• Lake Coombabah (only the freshwater component is located within the SEQ region).

Surface water makes up the majority of abstracted and used water resources within the SEQ region, with groundwater abstraction and use limited to various alluvial aquifers located along river valleys. Desalinated and recycled water resources within the SEQ region have been developed  in recent years. The requirements for supply from these alternative resources declined in 2010–11 due to higher than average rainfall over the SEQ region.

The overall surface water resource is highly developed in the SEQ region, with surface water management plans in place across the entire region.

Groundwater resources within the region are becoming more developed, with groundwater management areas (GMAs) now present across many high-use alluvial aquifers. It is expected that additional GMAs may be introduced as further development of groundwater occurs.

Agriculture and urban settlements are the main water users within the SEQ region. Water stored within surface water storages in the region is mainly for urban use. Recycled water and desalinated water supplement the surface and groundwater resources, for urban use and use in power supply.

Details of major storages in the SEQ region are listed in Table P4.

Major storages are defined as storages with a maximum storage capacity greater than 1,000 ML. In addition to the major storages listed in Table P4, numerous public storages with a storage capacity less than 1,000 ML exist within South East Queensland. These are not included in this account as the storage volume could not be quantified in a way that was complete, neutral and free from material error in accordance with Exposure Draft of Australian Water Accounting Standard 1. It is estimated that these storages have a combined total storage capacity in excess of 7,000 ML.

Table P4. Major water storages in the South East Queensland region

Water resource plan (WRP) area	Water supply scheme (WSS)	Storage name	Total storage capacity (ML)	Dead storage capacity (ML)
Gold Coast	Nerang	Advancetown Lake (Hinze Dam)6	310,730	0
		Little Nerang Dam	6,705	0
	Total Gold Coast WRP area		317,435	0
Logan Basin1	Logan River	Bromelton Off-Stream Storage3	8,210	0
		Cedar Grove Weir2	1,144	0
		Lake Maroon	44,319	0
	None	Tingalpa Reservoir (Leslie Harrison Dam)	24,868	0
		Wyaralong Dam5	102,883	0
	Total Logan Basin WRP area		181,424	0
Moreton	Central Brisbane River and Stanley River	Mount Crosby Weir2	3,430	0
		Lake Wivenhoe	1,165,238	0
		Lake Somerset	379,849	0
	Central Lockyer	Lake Clarendon	24,276	0
		Lake Dyer (Bill Gunn Dam)	6,947	0
	Cressbrook Creek	Lake Cressbrook	81,842	1,136
		Lake Perseverance	30,140	3,472
	Lower Lockyer	Lake Atkinson (Atkinson Dam)	30,400	0
	Pine Valley	Lake Samsonvale (North Pine Dam)	214,302	0
	Warrill Valley	Lake Moogerah	86,290	0
	None	Enoggera Reservoir	4,567	0
		Gold Creek Reservoir	1,436	0
		Lake Kurwongbah (Sideling Creek Dam)	14,370	0
		Lake Manchester (Cabbage Tree Creek Dam)	25,951	0
		Splityard Creek Dam	28,700	6,400
	Total Moreton WRP area		2,097,738	11,008
Total South East Queensland region			2,596,597	11,008

Notes:

1. Beaudesert Weir, with a total storage capacity of 9,130 ML was not included in the 2011 Account as information was not available on storage volumes for the 2010–11 year. For this reason Beaudesert Weir was not included in this table despite being located within the SEQ region.
2. Total storage capacity obtained from Seqwater.
3. Total storage capacity obtained from Bureau of Meteorology, Water storages product and does not include flood mitigation capacity.
4. All major surface water storages managed or owned by Seqwater have zero dead storage. Seqwater advised that due to installation of pumping systems none of their major surface water storages have any dead storage as all water is now able to be abstracted.
5. Wyaralong Dam was commissioned on 16 December 2010. Prior to this date the storage was not in operation and was not used to store water. Wyaralong Dam total storage capacity was obtained from Seqwater. A draft amendment to the Logan Basin Resource Operation Plan is currently under review to include this storage in the Logan River Water Supply Scheme. During the 2010–11 year this storage was not part of the Logan River Water Supply Scheme.
6. Advancetown Lake (Hinze Dam) stage 3 upgrade was completed in late 2011. The project raised the dam wall by approximately 15 metres and increased storage capacity from 161,073 to 310,730 ML.

Figure P4 shows mean monthly flow volumes in four main rivers within the SEQ region: Albert (145102B), Bremer (143107A), Brisbane (143001C) and Logan (145014A) rivers. Gauging stations on these rivers can be seen in Figure P5. Typically these rivers have flow throughout the year, with most of the flow occurring between December and June. The seasonal flow characteristics of these rivers reflect the rainfall pattern of the SEQ region, where a large proportion of rainfall occurs from December to March.

Figure P4. Graph of mean monthly flow along the Albert, Brisbane, Bremer and Logan rivers, mean monthly rainfall for the region is also shown


Figure P5. Map of key flow gauging stations along the main rivers within the South East Queensland region: Albert, Bremer, Brisbane and Logan rivers.

Groundwater extracted from alluvial aquifers is the primary source of water for the irrigation dominated upland valley such as the Lockyer Valley. Groundwater use is minor in the south of the SEQ region. Occasionally 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 groundwater systems of the SEQ region 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 Great Artesian Basin (GAB) underlies a large portion of Queensland. The groundwater resources in the GAB in Queensland are managed under the Water Resource (Great Artesian Basin) Plan 2006 and the Great Artesian Basin Resource Operations Plan 2007. This divides the Queensland component of the GAB into 25 groundwater management areas. One of these areas, the Clarence Moreton Management Area, is located partially within the South East Queensland (SEQ) 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 wide and extends from Toowoomba in the west to Darr Creek in the northwest, Esk in the north, Ipswich in the east and Rathdowney in the south (Department of Natural Resources, Mines and Water 2007). It underlies the Lockyer Valley, Bremer River Valley and Teviot Brook Catchment.

There are four GMAs within the SEQ region: Lockyer Valley, Warrill–Bremer Alluvial, Cressbrook Creek Alluvial and Watercourse Buffer Zone. The four GMAs are all located within the Moreton Water Resource Plan (WRP) area. These GMAs have yet to be included in the Moreton Resource Operations Plan (ROP). A model has been developed to estimate the groundwater asset in Implementation Area 1 of the Lockyer Valley GMA. Methods for calculating groundwater assets in the other GMAs in the SEQ region are still under investigation.

Figure P6. Map of alluvial aquifers in the South East Queensland region

Major urban infrastructure within the SEQ region can be seen in the Seqwater infrastructure map.

Potable water is supplied to residents across much of the SEQ region. In the heavily populated areas around Brisbane, Gold Coast, Logan City and Ipswich potable water is supplied through the SEQ Water Grid. A number of southeast Queensland residents live in communities that have drinking water supplies not directly connected to the SEQ Water Grid. These communities obtain water from a range of sources with varying levels of security, including unregulated rivers, groundwater and recycled water.

The SEQ Water Grid was established in July 2008 to connect water supplies and treatment facilities across the SEQ region. The SEQ Water 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 southeast Queensland access to more water sources, both dependent on climatic conditions (surface water storages) and resilient to climatic conditions (desalination and purified recycled water). The network includes about 450 kilometres of pipelines to move water from areas of surplus to areas of shortfall. Key components include 26 major surface water storages, 50 weirs, 46 water treatment plants and 14 groundwater bore fields. Water retailers within the SEQ region can be seen in Figure A2 in the Organisations responsible for water management section of the Contextual information.

Located outside the SEQ region, Toowoomba obtains raw water directly from surface water storages on Cressbrook and Perseverance Creeks which are within the region. Potable water is supplied into the SEQ region from the Sunshine Coast (via the Northern Pipeline Interconnector) and Stradbroke Island.

More information on the SEQ region's urban water systems can be found in the System's interactions with the region section of the Urban system note and the Australian Water Resource Assessment 2010 (Bureau of Meteorology 2011a).

Desalinated water from the Gold Coast Desalination Plant feeds directly into the SEQ Water Grid. With the SEQ region's dams full or near full, the Gold Coast Desalination Plant has been operating in 'hot standby' mode to minimise operating costs since December 2010. Under this mode of operation, the plant will typically produce around 25 ML/d of water two days a week, with no production in between. This small amount of production is needed to keep the membranes wet and the water in the pipes fresh, while retaining the capacity to ramp up to produce 44 ML/d (33%), 88 ML/d (66%) or 133 ML/d (100%) within 24 to 48 hours whenever required.

The plant may be called on if there are interruptions to supply in other parts of the SEQ Water Grid. An example of this was when the high level of rainfall during the 2010–11 year resulted in floods that caused high levels of sediment in the Brisbane River. The Gold Coast Desalination Plant production was increased to 66% to compensate for a reduction in production at Mount Crosby WTPs for a period of time after the floods.

Two main recycled water schemes exist within the SEQ region.

Gold Coast residential supply

Within the SEQ region, Class A+ recycled water is supplied to 3,700 homes and businesses in the Pimpama–Coomera area of the Gold Coast for toilet flushing and external non-drinking use. Industry also receives recycled water.

The recycled water treatment plant is part of the Pimpama–Coomera Waterfuture Master Plan. The Pimpama Coomera recycled water system was not included in this account as data were not available to quantify the volumes with any confidence.

Power station supply

The Western Corridor Recycled Water Scheme forms part of the SEQ Water Grid and supplies the Swanbank B and E Power Stations (located within the SEQ region), and Tarong and Tarong North Power Stations (located outside the SEQ region). Treated effluent from six wastewater treatment plants is further treated to purified recycled water at three separate advanced water treatment plants located at Bundamba, Gibson Island and Luggage Point.

When all three advanced water treatment plants are operating at capacity, the Western Corridor Recycled Water Scheme has a capacity of 232 ML/d subject to the availability of inflowing water from the wastewater treatment plants that supply the advanced water treatment plants.

Currently the power stations are the only users of the Western Corridor Recycled Water Scheme.

Off-channel storages exist in the SEQ region and are an important water resource for individuals who rely on them for water. There are approximately 1,700 off-channel storages within the region with an estimated storage volume of 59,000 ML.

The SEQ Water Grid extends to the north and east of the National Water Account SEQ region, sourcing water from and servicing the Sunshine Coast, Bribie Island and North Stradbroke Island. Surface water resources to the north of the SEQ region, in the Mary Water Resource Plan (WRP) area, supply water into the SEQ Water Grid. North Stradbroke Island and Bribie Island supply groundwater into the SEQ Water Grid. As the demand in these regions is less than the available supply, some of the water supplied from these three sources is transferred into the SEQ region via the SEQ Water Grid. This additional water is considered a water resource for the SEQ region.