Melbourne: Statement details
- Dry conditions for most of the year contributed to low runoff and storage inflows across the region.
- Total storage at 30 June 2019 was 53% full, the lowest end of year storage since 2010.
For further information on the region's water accounting statements scroll down this page or click on the links below:
Water assets
- Total water asset volumes in the region at 30 June 2019 were 1,603 GL, about two thirds of which is water held in storages.
- Around 30% of the water assets are inter-region claims and claims on water for the urban system. Less than 5% of the asset volume is water held in rivers, aquifers, and the urban system's wastewater storages.
Figure S1 Total storage volume in the region at 30 June 2019 compared with the previous 9 years
- Storage volumes decreased from 61% full at 30 June 2018 to 53% full at 30 June 2019. This is the second consecutive decrease in storage volume.
- The end of year storage volume at 30 June 2019 was the lowest since 2010.
Figure S2 Percentage-full volume on 30 June 2019 for each storage and total daily storage volume from 2013–2019 (inset)
- Storage volumes peaked in early-October 2018 following rainfall during the winter months.
- 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 Melbourne region refer to the volume of allocation remaining on licence entitlements at the end of the 2018–19 year.
Description | Individual users (ML) | Urban system (ML) | Transfer: inter-region | |
Opening balance at 1 July 2018 | 8,408 | 482,081 | 0 | |
add | Allocation | 6,978 | 611,350 | 5,425 |
less | Allocated diversion | 7,618 | 443,896 | 4,171 |
less | Adjustment and forfeiture | 1,810 | 207,594 | 1,254 |
Closing balance at 30 June 2019 | 5,958 | 441,941 | 0 |
Description | Individual users (ML) | Urban system (ML) | |
Opening balance at 1 July 2018 | 0 | 0 | |
add | Allocation | 64,628 | 1,499 |
less | Allocated extraction | 20,960 | 72 |
less | Adjustment and forfeiture | 43,668 | 1,427 |
Closing balance at 30 June 2019 | 0 | 0 |
- As there are no carryover provisions for groundwater supply licences in the region, the portion of water allocation that has not been abstracted at the end of a water year is forfeited and the allocation remaining at the end of the year was 0 ML.
- A more detailed description of water allocations and associated water rights in the Melbourne region is given in the Water access and use note.
Water flows
- Total surface water flows into the region's storages was estimated to be around 783 GL. The key item contributing to surface water inflows was runoff, which made up more than 70% of the total surface water inflows.
- Runoff was much lower than average (based on modelled data from 1971–2019) and the lowest in more than 10 years due to the relatively poor rainfall across the region. This was the second successive year of below-average runoff across the region.
- A key item contributing to surface water outflows from the region's storages was river outflow, which made around 44% of the total surface water outflows. River outflow was well below average due to the dry conditions and low runoff across the region.
- A detailed description on all the water flows associated with the surface water and groundwater stores, as well as the urban water system, is provided in the Water stores note.
Unaccounted-for difference
- 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.
Description | Volume (ML) | |
Closing water storage at 30 June 2019 | 1,097,810 | |
less | Total inflows | 1,899,960 |
add | Total outflows | 2,193,620 |
less | Opening water storage at 1 July 2018 | 1,248,628 |
Unaccounted-for difference | 142,842 |
- The unaccounted-for difference value is primarily attributed to uncertainties associated with the runoff and river outflow estimates (see Methods).