Canberra: Supporting information
- Dry conditions in the latter half of 2019 contributed to below-average annual runoff across the region.
- End-of-year storage was only slightly less than last year due to some rainfall relief in early 2020.
- 72% of the allocated water was taken in 2019–20, primarily for residential use.
For further information on the region's water accounting statements scroll down this page or click on the links below:
Water assets
- Water asset volumes in the region at 30 June 2020 were 199 GL, about 80% of which is water held in storages. The remaining amount is water held in lakes, rivers, and the urban distribution pipe network.
Figure S1 Total storage volume in the region at 30 June 2020 compared with the previous 10 years
- Storage volumes decreased slightly from 57% full at 30 June 2019 to 56% full at 30 June 2020.
- The end-of-year storage volume at 30 June 2020 was the lowest since 2010.
- In 2013 the Cotter Reservoir was enlarged, increasing the region's total storage capacity to better deal with water demand during periods of drought (see 2013 Account).
Figure S2 Percentage-full volume on 30 June 2020 for each storage and total daily storage volume from 2013–2020 (inset)
- In early February 2020, storage levels had dropped to 45% full, the lowest in more than 10 years.
- Higher rainfall during February–April 2020 resulted in a rise in storage levels across the region, the first significant rise in storage since June 2016.
- The low storage volume in Googong Reservoir (47% full at 30 June 2020) is significant. The reservoir had remained full, or near full, since the end of the Millennium Drought in 2010; however, from the start of 2017, the storage volume has dropped by more than 50%.
- More detailed information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website.
Water liabilities
- Water liabilities in the Canberra region refer to the volume of allocation remaining on licence entitlements at the end of the 2019–20 year.
Description | Individual users (ML) | Urban system (ML) | |
Opening balance at 1 July 2019 | 0 | 0 | |
add | Allocation | 8,338 | 71,060 |
less | Allocated diversion | 2,784 | 55,383 |
less | Adjustment and forfeiture | 5,554 | 15,677 |
Closing balance at 30 June 2020 | 0 | 0 |
Description | Individual users (ML) | |
Opening balance at 1 July 2019 | 0 | |
add | Allocated | 2,448 |
less | Allocation extraction | 1,064 |
less | Adjustment and forfeiture | 1,384 |
Closing balance at 30 June 2020 | 0 |
- The water supply licences for the region have a water management year that ends on 30 June. The portion of water allocation that has not been abstracted at the end of the water year is either forfeited or is carried over into the next water year.
- For individual users and the urban licence entitlement the unused portion of the allocation is assumed to be forfeited and the allocation remaining at the end of the year was 0 ML.
- A more detailed description of water allocations in the Canberra region is given in the Water use section below.
Water flows
Figure S3 Water inflows and outflows for the region's water stores and systems during the 2019–20 year
- Total surface water flows into the region's storages was 279 GL. The key item contributing to surface water inflows was runoff, which made up two thirds of the total surface water inflows.
- For the third consecutive year, runoff was much lower than average (based on modelled data from 1971–2020) due to relatively poor rainfall across the region.
- A key item contributing to surface water outflows from the region's storages was river outflow, which made up more than 50% of the total surface water outflows. River outflow was well below average due to the dry conditions and low runoff across the region, particularly during the latter half of 2019.
- Water taken from surface water and groundwater resources for consumptive use was 60 GL, around 20% of the total outflow (see Water use section below).
Water use
Figure S4 Water taken for consumptive use in the Canberra region in 2019–20
- Total surface water diverted in the region was 58,662 ML.
- 94% of the total diversion was for the urban system while 6% was supplied to individual users under allocated diversions and statutory rights.
- Total groundwater extracted in the region was 1,499 ML.
- All of the groundwater extractions were for individual users; 71% of the total were allocated extractions while 29% was made under a statutory right.
Figure S5 Surface water allocations and diversions in the Canberra region for the years ending 30 June, from 2012–2020
- In 2019–20, total surface water allocation was 79 GL, mostly for urban system supply. 73% of the allocated surface water was taken.
- Allocated diversion to the urban system was almost 5% higher than last year. The recent trend of increasing urban water supply reflects the dry conditions across the region over the last three years, which has resulted in an increased water demand from customers.
Figure S6 Groundwater allocations and extractions in the Canberra region for the years ending 30 June, from 2012–2020
- Total groundwater allocation was 2 GL, all for private and commercial use. 43% of the allocated groundwater was taken.
- Allocated extractions for individual users were similar to the previous few years.
Urban system supply
Figure S7 Water sources used in Canberra's urban supply system during the 2019–20 year compared with the previous nine years
- Total inflow to the water supply system was 55 GL, almost 5% higher than the previous year.
- Surface water diversions from the region's storages make up 100% of the urban supply.
Water restrictions
- Icon Water introduced permanent water conservation measures for potable water use in November 2010, which govern how water can be used on gardens and lawns and for pool filling, car washing, and cleaning.
- For more information, refer to the Bureau of Meteorology's Water Restrictions website.
Water market activity
- The volume of water allocation and entitlement traded in the region is small, typically representing less than 1% of the total water allocation.
- For more information on water markets in the region, see the Water Markets Dashboard.
Cultural and environmental water
Cultural benefit
- Cultural water values within the region are closely aligned with environmental water outcomes. In cases where complementary outcomes can be achieved, environmental water, delivered for environmental purposes, then also meet the cultural water requirements.
- More information on cultural water requirements are provided in the Cultural water management section in the 'Region description'.
Environmental benefit
Environmental water provisions
- Environmental water provisions are defined for aquatic ecosystem categories and specific river reaches in Chapter 5 of the 2013 Environmental Flow Guidelines.
- Environmental water requirements for one of these river reaches, on the Cotter River below Corin Dam, are presented below.
Figure S8 Example environmental water provisions for the Cotter River below Corin Dam
- The required environmental flows are maintained through a combination of strategic water releases or spills from storages, as well as by restricting the volume of water that can be diverted from a catchment.
- The baseflow requirement is specified on a monthly basis, with fortnightly variations in the rate of release preferred compared to constant discharge for the month.
- Drawdown limits for impoundments, and protection of larger, less frequent 'channel maintenance' flows are also a part of the environmental water provisions, but are not shown on the figure above.
Environmental water outcomes
Figure S9 Flow in the Cotter River compared with the required flow regime during the 2019–20 year
- In 2019–20, streamflow in the Cotter River below Corin Dam generally exceeded the monthly baseflow requirements.
- Streamflow exceeded the bi-monthly riffle maintenance requirements for most of the year; however, these requirements were not met during the summer months due to the very dry conditions across the region.
- Streamflow was well below the pool maintenance requirement.