Sydney: Water stores
Below-average rainfall during the majority of the year contributed to decreased runoff across the region compared to the previous year. Despite the relatively poor rainfall conditions, surface water availability was similar to last year; water use was also similar to the previous year.
For a water balance of each of the region's water stores for the 2016–17 year scroll down this page or click on the links below:
Surface water store
| 2017 ML |
2016 ML |
|
| Opening surface water store | 2,821,555 | 2,664,966 |
| Inflows | 4,654,903 | 5,125,053 |
| Outflows | (4,957,977) | (4,794,630) |
| Balancing item | 172,548 | (173,834) |
| Closing surface water store | 2,691,029 | 2,821,555 |
- The volume of surface water in the region decreased from 2,821,555 ML at 1 July 2016 to 2,691,029 ML at 30 June 2017.
- The balancing item of 172,548 ML is approximately 6% of the closing surface water store. The 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 S4 Water inflows and outflows for the surface water store during the 2016–17 year
- The largest natural water flows were runoff and outflow. Both were less than the previous year, reflecting the relatively poor rainfall experienced across the region for the majority of the year (see Climate and water).
- Evaporation was 25% higher than that which occurred during the previous year, which can be attributed to the decreased rainfall (and hence cloud cover) that occurred during the year.
Figure S5 Surface water diversions to the urban system by WaterNSW during the 2016–17 year
- Total surface water diverted in the region was 614,546 ML, 92% of which was for urban supply by the bulk supplier WaterNSW.
- 3% of the total diversion was for individual users under an allocation; 5% was for individual users under statutory rights.
- For a more detailed description of the water usage in the region, and the associated entitlements, see the Surface water rights note.
Urban water system
| 2017 ML |
2016 ML |
|
| Opening urban water system | – | – |
| Inflows | 1,125,786 | 1,102,892 |
| Outflows | (1,117,802) | (1,087,676) |
| Balancing item | (7,984) | (15,216) |
| Closing urban water system | – | – |
- 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 likely attributed to metering inaccuracies, unaccounted losses, and inaccuracies in the estimation of certain volumes (see Methods).
Urban water system flows
Figure S6 Water inflows and outflows for the urban water system during the 2016–17 year
- A more detailed breakdown of the inflows and outflows of the urban water system components is provided in the urban water balance diagram.
Water supply inflows
Figure S7 Water sources used in the Sydney region's urban supply system during the 2016–17 year compared with the previous 6 years
- Total inflows to the water supply system was 563,744 ML, similar to the previous year.
- Surface water diversion from the region's storages made up 100% of the urban water supply.
- No desalinated water has been required to meet urban demand for the past 5 years.
Wastewater and recycled water inflows
- Wastewater collected was 562,042 ML during the 2016–17 year.
Water supply outflows
Figure S8 Outflows from the water supply system
- The majority of water supply outflow was supply system delivery: urban users.
- 10% of the total outflow from the urban supply system was related to losses, similar to the previous year.
Wastewater and recycled water outflows
Figure S9 Outflows from the wastewater and recycled water systems
- 2% of the treated wastewater was recycled water delivery: urban users, similar to the previous year.
- Most of the remaining treated wastewater was discharge: sea and, to a much lesser extent, discharge: surface water.
- 3% of the total outflow was related to losses.