Canberra: Water stores
- Below-average rainfall during most of the year contributed to low runoff across the region and a decrease in storage volumes.
- Water use increased compared to last year, reflecting the drier conditions across the region.
For a water balance of 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 | 2018 (ML) | |
| Opening surface water store | 279,006 | |
| add | Inflows | 474,120 |
| less | Outflows | 503,863 |
| less | Balancing item | 12,624 |
| Closing surface water store | 236,639 | |
- The volume of surface water in the region decreased from 279,006 ML at 1 July 2017 to 239,639 ML at 30 June 2018.
- The balancing item is negligible relative to the closing surface water store. The balancing item is primarily attributed to uncertainties associated with runoff and outflow estimates (see Methods).
Surface water flows
Figure S2 Water inflows and outflows for the surface water store during the 2017–18 year
- The largest natural water flow in the region was runoff, which was below average compared to previous years and, in particular, substantially lower than the last two years. This can be attributed to the dry conditions experienced across the region (see Climate and water).
- Other natural water flows include inter-region inflow and outflow. Both were well below average compared to previous years, a reflection of the dry conditions.
Figure S3 Surface water diversions during the 2017–18 year in the region's key water management areas
- Total surface water diverted in the region was 55,295 ML.
- 92% of the total diversion was for the urban system; with 8% supplied to individual users under non-allocated diversions and statutory rights.
- Diversions from the Googong Reservoir for urban supply more than doubled. In recent years, Corin and Bendora reservoirs have been the primary sources of water for urban supply in the region. The increased diversions from Googong reflect the drier conditions experienced throughout the region.
- 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 | 2018 (ML) | |
| Opening groundwater store | – | |
| add | Inflows | 167,021 |
| less | Outflows | 1,265 |
| less | Balancing item | 165,756 |
| Closing groundwater store | – | |
- The volume of groundwater in the region is assumed to remain unchanged throughout the year.
- The large groundwater balancing item is primarily attributed to uncertainties associated with the groundwater recharge from surface water volume and natural groundwater flows that could not be quantified.
Groundwater flows
Figure S4 Water inflows and outflows for the groundwater store during the 2017–18 year
- The majority of groundwater inflows came from recharge: surface water.
- Groundwater movement across the region boundary are considered to occur within the region; however, these flows could not be quantified due to a lack of available data.
- Total groundwater extracted in the region was 1,265 ML.
- 66% of total extraction was for non-allocated extractions: individual users; 34% for extraction: statutory rights.
- 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 | 2018 (ML) | |
| Opening urban water system | – | |
| add | Inflows | 89,109 |
| less | Outflows | 86,957 |
| less | Balancing item | 2,152 |
| Closing urban water system | – | |
- The volume of water stored in the region's urban system comprises water in the pipe network and is assumed to remain unchanged during the year.
- The balancing item is likely 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 urban water system during the 2017–18 year
Water supply inflows
Figure S6 Water sources used in Canberra's urban supply system during the 2017–18 year compared with the previous 6 years
- Total inflow to the water supply system was 52,408 ML, more than the previous year.
- Surface water diversions from the region's storages made up more than 99% of urban supply; the remainder was from inter-region delivery.
Wastewater and recycled water inflows
- Wastewater collected was 36,701 ML during the 2017–18 year.
Water supply outflows
Figure S7 Outflows from the water supply system
- The majority of water supply outflow was supply system delivery to urban users.
- 11% of the total outflow from the urban supply system was related to losses, similar to the previous year.
Wastewater and recycled water outflows
Figure S8 Outflows from the wastewater and recycled water systems
- Most of the treated wastewater was discharge: surface water.
- Less than 1% of the treated wastewater was recycled, similar to last year.