Perth: Statement of Changes in Water Assets and Water Liabilities
Water availability in the Perth region decreased by 33,442 ML during the 2015–16 year. This follows a small increase in water availability in the region 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 is prepared on an accrual basis and presents the changes in water assets and water liabilities that occurred during the reporting year. These changes include accrual transactions (e.g. allocations and forfeitures) and actual water flows, both natural and engineered.
Items in the statements are hyperlinked to the associated section of the Statement details. Methods used to derive item volumes are provided in the Reference information.
for the year ended 30 June 2016
| 2016 ML | 2015 ML | |
|---|---|---|
| Water asset increases | ||
| Surface water increases | 373,338 | 573,079 |
| Precipitation | 16,824 | 21,238 |
| Runoff | 352,148 | 549,983 |
| Delivery: inter-region | 4,366 | 1,858 |
| Total surface water increases | 373,338 | 573,079 |
| Groundwater increases | 1,212,581 | 1,349,748 |
| Inter-region inflow | 47,475 | 45,218 |
| Inter-region coastal inflow | 0 | 0 |
| Recharge: landscape | 1,165,106 | 1,304,530 |
| Total groundwater increases | 1,212,581 | 1,349,748 |
| Urban water system increases | 279,456 | 262,150 |
| Wastewater collected | 138,858 | 140,771 |
| Supply system delivery: inter-region | 1,953 | 1,922 |
| Delivery: desalinated water | 138,645 | 119,457 |
| Total urban water system increases | 279,456 | 262,150 |
| Total water asset increases | 1,865,375 | 2,184,977 |
| Water liability decreases | ||
| Surface water liability decreases | 50 | 4,045 |
| Adjustment and forfeiture: individual users | 50 | 4,045 |
| Total surface water liability decreases | 50 | 4,045 |
| Groundwater liability decreases | 8,755 | 13,637 |
| Adjustment and forfeiture: individual users | 8,755 | 13,637 |
| Total groundwater liability decreases | 8,755 | 13,637 |
| Total water liability decreases | 8,805 | 17,682 |
| Water asset decreases | ||
| Surface water decreases | 206,658 | 427,127 |
| Evaporation | 28,912 | 46,052 |
| Outflow | 177,596 | 380,925 |
| Leakage: landscape | 150 | 150 |
| River and floodplain losses | – | – |
| Total surface water decreases | 206,658 | 427,127 |
| Groundwater decreases | 735,954 | 823,044 |
| Inter-region outflow | 21,863 | 23,439 |
| Inter-region coastal outflow | 300,629 | 341,881 |
| Discharge: landscape | 332,617 | 378,114 |
| Non-allocated extraction: individual users | 80,845 | 79,610 |
| Total groundwater decreases | 735,954 | 823,044 |
| Urban water system decreases | 411,311 | 406,371 |
| Supply system delivery: urban users | 236,200 | 232,537 |
| Recycled water delivery: urban users | 9,095 | 8,035 |
| Discharge: sea | 123,163 | 125,025 |
| Discharge: landscape | 6,145 | 5,962 |
| Supply system transfer: inter-region | 27,923 | 24,796 |
| Other supply system decreases | 8,785 | 10,016 |
| Total urban water system decreases | 411,311 | 406,371 |
| Irrigation scheme decreases | 32,197 | 31,426 |
| Delivery | 32,197 | 31,426 |
| Total irrigation scheme decreases | 32,197 | 31,426 |
| Total water asset decreases | 1,386,120 | 1,687,968 |
| Water liability increases | ||
| Surface water liability increases | 38,842 | 38,556 |
| Allocation: individual users | 38,842 | 38,556 |
| Total surface water liability increases | 38,842 | 38,556 |
| Groundwater liability increases | 306,671 | 287,753 |
| Allocation: individual users | 306,671 | 287,753 |
| Total groundwater liability increases | 306,671 | 287,753 |
| Total water liability increases | 345,513 | 326,309 |
| Unaccounted-for difference | ||
| Unaccounted-for difference | (175,989) | (179,431) |
| Unaccounted-for difference | (175,989) | (179,431) |
| Total unaccounted-for difference | (175,989) | (179,431) |
| Total unaccounted-for difference | (175,989) | (179,431) |
| Change in net water assets | (33,442) | 8,951 |