Canberra: Water stores
Despite relatively poor rainfall conditions for most of the year, heavy rainfall in September contributed to higher runoff across the region and a slight increase in surface water storage from last year. Water supply was similar to last 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 | 273,135 | 265,119 |
| Inflows | 1,016,119 | 957,231 |
| Outflows | (976,390) | (805,417) |
| Balancing item | (33,858) | (143,798) |
| Closing surface water store | 279,006 | 273,135 |
- The volume of surface water in the region increased slightly from 273,135 ML at 1 July 2016 to 279,006 ML at 30 June 2017.
- The balancing item of –33,858 ML is 12% of the closing surface water store. The relatively high balancing item is 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 S5 Water inflows and outflows for the surface water store during the 2016–17 year
- The largest natural water flows in the region were runoff and outflow. Both were higher than the previous year, which can be attributed to heavy rainfall in September that caused very high flows across the region (see Climate and water).
- Evaporation was 25% higher than that which occurred during the previous year, which may be attributed to increased surface water availability across the region following high rainfall in September.
Figure S6 Surface water diversions during the 2016–17 year in the region's key water management areas
- Total surface water diverted in the region was 52,381 ML, similar to the previous year.
- 96% of the total diversion was for the urban system; 4% was for licenced individual users.
- Diversions to individual users under statutory rights could not be quantified due to a lack of available data.
- For a more detailed description of the water usage in the region, and the associated entitlements, see the Surface water rights note.
Groundwater store
| 2017 ML | 2016 ML | |
| Opening groundwater store | – | – |
| Inflows | 4,079 | 4,454 |
| Outflows | (1,259) | (1,276) |
| Balancing item | (2,820) | (3,178) |
| Closing groundwater store | – | – |
- The volume of groundwater in the region is assumed to remain unchanged throughout the year.
- Given that the volume of water in aquifers and the natural groundwater movement in the region cannot be quantified, the balancing item is simply the difference between the leakage from the urban water system and the total volume of groundwater extraction.
Groundwater flows
Figure S7 Water inflows and outflows for the groundwater store during the 2016–17 year
- Groundwater movement across the region boundary as well as surface water–groundwater interactions 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 1,259 ML, similar to the previous year.
- 65% of total extraction was for non-allocated extractions: individual users; 35% 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
| 2017 ML | 2016 ML | |
| Opening urban water system | – | – |
| Inflows | 90,960 | 89,049 |
| Outflows | (87,731) | (85,518) |
| Balancing item | (3,229) | (3,531) |
| 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 uncertainties in the estimation of certain volumes (see Methods).
Urban water system flows
Figure S8 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 S9 Water sources used in Canberra's urban supply system during the 2016–17 year compared with the previous 6 years
- Total inflow to the water supply system was 50,139 ML, similar to 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 40,821 ML during the 2016–17 year, a 6% increase from the previous year.
Water supply outflows
Figure S10 Outflows from the water supply system
- The majority of water supply outflow was supply system delivery to 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 S11 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.