Perth: Outlook for 2018 Account
as at 1 June 2018
Above-average rainfall was observed across the region during the first 11 months of the 2017–18 year, which may lead to small rises in end of year surface water and aquifer storage. Water use is expected to be similar to the previous year but may include more surface water. Total water assets are expected to remain in surplus at 30 June 2018.
For further information on the expected inflows and future commitments for the region during the 2017–18 year scroll down this page.
Future prospects
Figure S25 Water outlook for the Perth region for 2017–18
- There is a surplus of available water assets and future water rights over water liabilities and future water commitments that are expected to be settled within 12 months of the reporting date.
Expected inflows
Figure S26 Rainfall deciles for the Perth region from July 2017–May 2018
- Average to above-average rainfall across most of the region during the first 11 months of the 2017–18 year (July–May) has resulted in higher storage inflows compared to the previous few years.
- Storage levels were 40% full at 1 June 2018 compared to 32% full at the same time last year.
- According to the Bureau's climate outlook (from 31 May 2018), the main climate drivers, such as the El Niño–Southern Oscillation and the Indian Ocean Dipole, will remain neutral during the winter months, which will mean the region is unlikely to experience above-average rainfall in June 2018.
- Annual storage inflows are expected to be higher than the past several years but still below the long-term average.
- The Groundwater Replenishment Scheme started operation in late 2017 and is expected to contribute to groundwater recharge. Net groundwater recharge is expected to be slightly higher than the previous year.
Future commitments
- Predictions of expected use in 2017–18 are based on the expectations of around average rainfall and a moderate increase in surface water storage.
- Usage by individual groundwater and surface water users may decline slightly due to government compliance activities and reduced demand related to wetter rainfall conditions.
- The urban system is likely to re-establish the use of some surface water in 2017–18, with a possible accompanying small reduction in groundwater use. Overall urban use is likely to be similar to the previous year.
- Irrigation diversions are likely to increase slightly due to an increase in allocations in the Harvey and Waroona districts to 60% in 2017–18 from 45% in the previous year.
- Possible small decreases in individual licensed use may be balanced by small increases in irrigation use such that overall water use is expected to be similar to the previous year.