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National Water Account 2017

Perth: Statement of Changes in Water Assets and Water Liabilities

Water availability in the Perth region increased by 39,883 ML during the 2016–17 year. This follows a decrease in water availability in the previous year. The change in water available in the region at the end of the year is represented by the change in net water assets.

The Statement of Changes in Water Assets and Water Liabilities is provided in the table below. The statement presents the changes in water assets and water liabilities that occurred during the year, including accrual transactions (e.g. allocations and forfeitures) and actual water flows, both natural and engineered.


 2017 ML2016 ML
Water asset increases
Surface water increases1,341,861438,728
Delivery: inter-region00
Inter-region inflow444,08369,756
Flood return19,919
Groundwater increases1,612,8251,212,581
Inter-region inflow45,72447,475
Inter-region coastal inflow00
Recharge: landscape1,567,1011,165,106
Urban water system increases292,143279,456
Wastewater collected140,439138,858
Supply system delivery: inter-region1,8321,953
Delivery: desalinated water149,872138,645
Total water asset increases3,246,8291,930,765
Water liability decreases
Surface water liability decreases2150
Adjustment and forfeiture: individual users2150
Groundwater liability decreases12,5418,755
Adjustment and forfeiture: individual users12,5418,755
Total water liability decreases12,5628,805
Water asset decreases
Surface water decreases1,560,606225,475
Leakage: landscape150150
River losses238,759
Overbank flow51,454
Groundwater decreases751,022735,954
Inter-region outflow19,35021,863
Inter-region coastal outflow261,169300,629
Discharge: landscape389,247332,617
Non-allocated extraction: individual users81,25680,845
Urban water system decreases387,682411,311
Supply system delivery: urban users224,799236,200
Recycled water delivery: urban users8,6229,095
Discharge: sea119,190123,163
Discharge: landscape5,7346,145
Supply system transfer: inter-region20,88327,923
Other supply system decreases8,4548,785
Irrigation scheme decreases59,37770,657
Leakage: landscape15,92117,201
Total water asset decreases2,758,6871,443,397
Water liability increases
Surface water liability increases38,87338,842
Allocation: individual users38,87338,842
Groundwater liability increases299,034306,671
Allocation: individual users299,034306,671
Total water liability increases337,907345,513
Unaccounted-for difference(122,914)(221,217)
Change in net water assets39,883(70,557)