South East Queensland: Water stores
- Relatively poor rainfall conditions contributed to low runoff across the region for most of the year.
- High rainfall in October and February contributed to an increase in end of year storage, despite the otherwise dry conditions.
- Surface water diversion was similar to last year, while groundwater extraction increased by 13%.
For a water balance on each of the region's water stores for the 2017–18 year scroll down this page or click on the links below:
Surface water store
| Description | Volume (ML) | |
| Opening surface water store | 2,033,812 | |
| add | Inflows | 2,900,626 |
| less | Outflows | 2,538,014 |
| add | Balancing item | (268,199) |
| Closing surface water store | 2,128,225 | |
- The volume of surface water in the region increased from 2,033,812 ML at 1 July 2017 to 2,128,225 ML at 30 June 2018.
- The relatively high balancing item is primarily attributed to the fact that river losses cannot be quantified in the account, as well as uncertainties associated with the runoff estimate (see Methods).
Surface water flows
Figure S3 Water inflows and outflows for South East Queensland's surface water store during the 2017–18 year
- The largest natural water flows were runoff and river outflow. These were both below average compared to previous years due to the below-average rainfall for most months of the year (see Climate and water).
- Total surface water diverted in the region was 353,722 ML.
- Approximately 94% of the total diversion was for the urban system, with the remainder supplied to individual users.
- For a more detailed description of the water usage in the region, and the associated entitlements, see the Surface water rights note.
Groundwater store
| Description | Volume (ML) | |
| Opening groundwater store | 11,115 | |
| add | Inflows | 26,654 |
| less | Outflows | 19,788 |
| add | Balancing item | (6,866) |
| Closing groundwater store | 11,115 | |
- The volume of groundwater in the region is equivalent to the permissible consumptive volume, which is the legal extractable limit and, therefore, remains unchanged from year to year.
- The balancing item of -6,866 ML is due to the inability to quantify groundwater fluxes such as recharge and discharge, as well as the assumption of constant volume in the groundwater store.
Groundwater flows
Figure S4 Water inflows and outflows for South East Queensland's groundwater store during the 2017–18 year
- Natural groundwater movement across the region boundary is considered to occur within the region; however, these flows could not be quantified.
- Total groundwater extracted in the region was 19,788 ML.
- 63% of groundwater extraction was for individual users (comprising both allocated and non-allocated extraction), with 37% for the urban water system.
- For a more detailed description of the water usage in the region and the associated entitlements, see the Groundwater rights note.
Urban water system
| Description | Volume (ML) | |
| Opening urban water system | 0 | |
| add | Inflows | 612,402 |
| less | Outflows | 609,162 |
| add | Balancing item | (3,240) |
| Closing urban water system | 0 | |
- The volume of water in the region's urban system comprises water in the pipe network. As no major pipe network changes were made, this volume is assumed to remain unchanged throughout the year.
- The balancing item is attributed to metering inaccuracies, unaccounted losses, and uncertainties in the estimation of certain volumes (see Methods).
Urban water system flows
Figure S5 Water inflows and outflows for the South East Queensland's urban water system during the 2017–18 year
Water supply inflows
Figure S6 Water sources used in South East Queensland's urban water system during the 2017–18 year compared with the previous seven years
- Total water supplied to the urban system was 341,528 ML, similar to last year.
- Surface water made up 97% of urban supply, while groundwater and desalinated water made up 2% and less than 1% of urban supply, respectively.
Wastewater and recycled water inflows
- Wastewater collected was 270,874 ML during the 2017–18 year.
Water supply outflows
Figure S7 Outflows from the water supply system
- The majority of water supply outflow was delivery to urban users.
- Approximately 11% of the total outflow from the urban supply system was related to losses.
Wastewater and recycled water system outflows
Figure S8 Outflows from the wastewater and recycled water systems
- 5% of treated wastewater was recycled and delivered to urban users.
- Most of the remaining treated wastewater was discharged to sea.