Perth: Statement of Changes in Water Assets and Water Liabilities
The Statement of Changes in Water Assets and Water Liabilities presents the changes in water assets and water liabilities that occurred during the reporting year.
This statement is prepared on an accrual basis. The changes in water assets and water liabilities are recognised when the claim to water or the obligation to deliver it is recorded and not when the actual flow occurs. Figure W2 shows the transactions that change the water assets and water liabilities of the region, including:
- accrual (non-physical) transactions, indicated by the glass-of-water symbols
- actual water flows (both natural and engineered), indicated by the arrows.
Figure W2 Changes in water assets and water liabilities for the region during the 2014–15 year
More detail on the changes in water assets and water liabilities for the 2014–15 year is provided in the Statement of Changes in Water Assets and Water Liabilities below.
Items in the statements are hyperlinked to the associated section of the Supporting information notes. Methods used to derive line item volumes are provided in the Quantification approaches notes.
for the year ended 30 June 2015
| 2015 ML | 2014 ML | |
|---|---|---|
| Water asset increases | ||
| Surface water increases | 573,079 | 814,691 |
| Precipitation | 21,238 | 25,009 |
| Runoff | 549,983 | 787,143 |
| Delivery: inter-region | 1,858 | 2,539 |
| Total surface water increases | 573,079 | 814,691 |
| Groundwater increases | 1,349,748 | 1,990,720 |
| Inter-region inflow | 45,218 | 52,788 |
| Inter-region coastal inflow | 0 | 0 |
| Recharge: landscape | 1,304,530 | 1,937,932 |
| Total groundwater increases | 1,349,748 | 1,990,720 |
| Urban water system increases | 262,150 | 256,205 |
| Wastewater collected | 140,771 | 141,024 |
| Supply system delivery: inter-region | 1,922 | 2,121 |
| Delivery: desalinated water | 119,457 | 113,060 |
| Total urban water system increases | 262,150 | 256,205 |
| Total water asset increases | 2,184,977 | 3,061,616 |
| Water liability decreases | ||
| Surface water liability decreases | 4,045 | 5,219 |
| Adjustment and forfeiture: individual users | 4,045 | 5,219 |
| Total surface water liability decreases | 4,045 | 5,219 |
| Groundwater liability decreases | 13,637 | 14,172 |
| Adjustment and forfeiture: individual users | 13,637 | 14,172 |
| Total groundwater liability decreases | 13,637 | 14,172 |
| Total water liability decreases | 17,682 | 19,391 |
| Water asset decreases | ||
| Surface water decreases | 427,127 | 589,186 |
| Evaporation | 46,052 | 33,600 |
| Outflow | 380,925 | 555,390 |
| Leakage: landscape | 150 | 196 |
| River and floodplain losses | – | – |
| Total surface water decreases | 427,127 | 589,186 |
| Groundwater decreases | 823,044 | 1,160,149 |
| Inter-region outflow | 23,439 | 30,164 |
| Inter-region coastal outflow | 341,881 | 433,999 |
| Discharge: landscape | 378,114 | 622,737 |
| Non-allocated extraction: individual users | 79,610 | 73,249 |
| Total groundwater decreases | 823,044 | 1,160,149 |
| Urban water system decreases | 406,371 | 404,352 |
| Supply system delivery: urban users | 232,537 | 234,774 |
| Recycled water delivery: urban users | 8,035 | 8,203 |
| Discharge: sea | 125,025 | 124,900 |
| Discharge: landscape | 5,962 | 5,673 |
| Supply system transfer: inter-region | 24,796 | 20,797 |
| Other supply system decreases | 10,016 | 10,005 |
| Total urban water system decreases | 406,371 | 404,352 |
| Irrigation scheme decreases | 31,426 | 33,622 |
| Delivery | 31,426 | 33,622 |
| Total irrigation scheme decreases | 31,426 | 33,622 |
| Total water asset decreases | 1,687,968 | 2,187,309 |
| Water liability increases | ||
| Surface water liability increases | 38,556 | 33,958 |
| Allocation: individual users | 38,556 | 33,958 |
| Total surface water liability increases | 38,556 | 33,958 |
| Groundwater liability increases | 287,753 | 287,262 |
| Allocation: individual users | 287,753 | 287,262 |
| Total groundwater liability increases | 287,753 | 287,262 |
| Total water liability increases | 326,309 | 321,220 |
| Unaccounted-for difference | ||
| Unaccounted-for difference | (179,331) | 513,279 |
| Unaccounted-for difference | (179,331) | 513,279 |
| Total unaccounted-for difference | (179,331) | 513,279 |
| Total unaccounted-for difference | (179,331) | 513,279 |
| Change in net water assets | 9,051 | 59,199 |