Perth region
Overview: 2013–14
The Perth region is home to waterways and wetlands of national significance. The region also contains important groundwater resources that support numerous groundwater-dependent wetland ecosystems. In the last 30 years, the region has experienced a decline in rainfall that has resulted in a reduction in storage refill and aquifer recharge.
Rainfall across the entire Perth region was near average for the 2013–14 year and approximately 30% more than the previous year. Despite the generally average rainfall conditions, streamflow in the Swan and Murray rivers was below average, which is likely to be a result of the generally dry soil conditions across most the region during the year. The improved rainfall conditions, compared to the 2012–13 year, contributed to increased inflows into the storages and an increase in aquifer recharge. Closing net water assets in the Perth region was 83,273 ML, higher than the previous year of 24,074 ML. For more information on the region's water assets refer to Water accounting statements.
During the 2013–14 year the second stage of the Southern Seawater Desalination Plant was fully commissioned, which has doubled the plant's capacity to 100,000 ML per year. Desalinated water contributed 39% of urban water supply this year, an increase of more than 17,000 ML from the previous year. Consequently, there was slightly less dependence on groundwater for urban supply compared to the previous year.
The key water account information for the Perth region during the 2013–14 year is presented in the following table. Information on the uncertainty associated with the volumes presented in the table is provided in the relevant sections of the account.
Contextual information
 | 2013–14 | 2012–13 | Long–term average |
| Rainfall: 777 mm | Rainfall: 586 mm | Rainfall: 800 mm | |
| For more detail on the Perth climate refer to Climate overview. | |||
 | Swan-Canning River | Murray River | Harvey River |
| below mean annual flow | below mean annual flow | mean annual flow | |
| For more detail on streamflow in the Perth region refer to Water overview. | |||
Water accounting statements
 | 2013–14 | 2012–131 | |
| Total water assets (as at 30 June) | 212,290 | 166,641 | |
| Total water liabilities (as at 30 June) | 129,017 | 142,567 | |
| Change in net water assets | 59,199 | (5,378) | |
| Closing net water assets | 83,273 | 24,074 | |
| For more detail on water assets and water liabilities refer to Water accounting statements. | |||
1 These volumes vary from those published in the 2013 Account. Please refer to Water accounting policies for more detail.
Notes: supporting information
 | 30 June 2014 | 30 June 2013 | |||
| Total capacity | Volume | % of capacity | Volume | % of capacity | |
| 655,300 ML | 204,898 ML | 31.3% | 159,492 ML | 24.3% | |
| For more detail on surface water storage in the Perth region refer to Surface water. | |||||
 | Total water abstracted | ||
| 2013–14 | 2012–13 | Recent activity | |
| Surface water: 174,325 ML | Surface water: 142,580 ML | Surface water abstractions increased. | |
| Groundwater: 479,618 ML | Groundwater: 486,741 ML | ||
| For more detail on water abstraction in the Perth region refer to Surface water and Groundwater. | |||
 | Total water supplied | ||
| 2013–14 | 2012–13 | Recent activity | |
| 289,114 ML | 284,058 ML | Increased dependence on desalinated water supply. | |
| For more detail on the urban water system in the Perth region refer to Urban water system. | |||
 | Total water supplied | ||
| 2013–14 | 2012–13 | Recent activity | |
| 34,466 ML | 21,910 ML | Diversion of surface water for irrigation increased. | |
| For more detail on the irrigation scheme in the Perth region refer to Irrigation scheme. | |||