South East Queensland: Statement details
The region experienced below-average rainfall during the 2015–16 year, particularly during December–May, which are typically the wettest months of the year. This contributed to low annual streamflows and storage inflows across the region. Surface water storage dropped from 95% to 82% full during the year.
- Water assets
- Water liabilities
- Water assets increases
- Water assets decreases
- Water flows
- Unaccounted-for difference
Water assets
Surface water assets
The surface water asset volume in the South East Queensland region at 30 June 2016 was 2,213,337 ML, which represents the volume of water held in storages. The location of each storage within the region and the volume of water in each storage as a percentage of total storage capacity at the end of the year is shown in Figure S1.
The volume of water in rivers, lakes and wetlands could not be quantified due to a lack of available data. The volume of water held in rivers and lakes is considered to be relatively small compared to the volume held in storages.
Figure S1 Percentage-full volume on 30 June 2016 for each storage
There are 26 major surface water storages in the region with a total capacity of almost 2,700,000 ML. Five storages (Wivenhoe, Somerset, Hinze, North Pine and Wyaralong) provide more than 80% of the region's total capacity.
The overall storage volume within the region decreased during the 2015–16 year from 95% to 82% full at 30 June 2016 (Figure S2). This drop in storage volume was largely due to below-average rainfall and streamflow across the region during the year (see Climate and water).
Information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website
Figure S2 Total region storage volume at 30 June 2016 compared with the previous 5 years
Groundwater assets
The aquifers in the South East Queensland region are described in the Groundwater section of the 'Geographic information'. The groundwater asset volume for the South East Queensland region represents permissible consumptive volumes for water table aquifers (11,115 ML).
Water liabilities
Water liabilities in the South East Queensland region refer to the volume of allocation remaining on licence entitlements at the end of the 2015–16 year for:
- surface water: individual users—0 ML
- groundwater: individual users—0 ML.
The water supply licences for the region have a water management year that ends on 30 June. Allocation carryover from one water year to the next does not occur in the South East Queensland region. The portion of water allocation that has not been abstracted at the end of the water year is forfeited; therefore, allocation remaining at 30 June is 0 ML (tables S1–S2). The allocation (water liability increases), allocated abstraction (water outflow), and the adjustment and forfeiture (water liability decreases) for each licence entitlement is also provided.
A more detailed description of water allocations and associated water rights in the region is given in the Water rights note.
| Volume (ML) | |
| Opening balance at 1 July 2015 | 0 |
| Allocation | 63,664 |
| Allocated diversion | (27,388) |
| Adjustment and forfeiture | (36,276) |
| Closing balance at 30 June 2016 | 0 |
| Volume (ML) | |
| Opening balance at 1 July 2015 | 0 |
| Allocation | 9,335 |
| Allocation extraction | (4,518) |
| Adjustment and forfeiture | (4,817) |
| Closing balance at 30 June 2016 | 0 |
Water asset increases
Total water asset increases for the region (2,125,154 ML) comprised:
- surface water increases—1,878,545 ML
- groundwater increases—0 ML
- urban water system increases—246,609 ML.
The key water asset increase for the region was runoff, which made up 80% of the total water asset increases. This flow was approximately 70% less than the previous year, which reflects the relatively poor rainfall experienced across the region for the majority of the year (see Climate and water).
Urban water system increases primarily represents wastewater collected, which generally changes little from year to year.
Water asset decreases
Total water asset decreases for the region (2,421,377 ML) comprised:
- surface water decreases—1,908,490 ML
- groundwater decreases—4,951 ML
- urban water system decreases—507,936 ML.
The key water asset decrease for the region was outflow, which made up more than 50% of the total water asset decreases. This flow was less than the previous year, which primarily reflects the relatively poor rainfall experienced across the region over most of the year (see Climate and water).
Groundwater decreases represents non-allocated extraction: individual users. Extraction increased from the previous year, reflecting the poor rainfall experienced across the region that increased users' reliance on water supplied directly from aquifers. Urban water system decreases primarily represents supply system delivery: urban users and discharge: sea, which generally changes little from year to year.
Water flows
The volume of total water inflows to the region (2,125,154 ML) was equal to the volume of Water asset increases. The volume of total water outflows from the region (2,453,283 ML) was marginally higher than that of Water asset decreases (2,421,377 ML) because the volume of water outflows also includes the flows corresponding to the accrual transactions, that is, the allocated diversions and extractions of water (see the Water liabilities section above).
A detailed description of all the water flows associated with the surface water and groundwater stores and urban water system is provided in the Water stores note.
Unaccounted-for difference
The volume reconciled in the water accounting statements (22,879 ML) represents the total unaccounted-for difference for the South East Queensland region for the 2015–16 year.
The unaccounted–for difference is the volume necessary to reconcile the opening water storage and closing water storage with the total water inflows and total water outflows reported in the water accounting statements. It is calculated according to Table S3.
| Volume (ML) | |
| Opening water storage balance at 1 July 2015 | 2,575,460 |
| Total water inflows | 2,125,154 |
| Total water outflows | (2,453,283) |
| Closing water storage balance at 30 June 2016 | (2,224,452) |
| Unaccounted-for difference | (22,879) |
The unaccounted-for difference can also be calculated by adding the volumes necessary to reconcile (balance) the opening and closing storage with the water inflows and outflows of each of the separate water stores of the region, as shown in Table S4.
| Volume (ML) | |
| surface water store | (14,165) |
| groundwater store | (7,743) |
| urban water system | (971) |
| Unaccounted-for difference | (22,879) |
The unaccounted-for difference volume is primarily explained by the balancing item of the surface water store. The surface water balancing item is largely attributed to uncertainty associated with runoff to surface water and river outflow, as well as the inability to quantify the volume of river and floodplain losses (see Surface water note).