Drier than average conditions in 2017 have resulted in a drop in Melbourne’s water storage levels, according the latest figures from Melbourne Water.
On 31 December 2017, Melbourne’s water storages were 69.3 per cent full, down 36.8 billion litres (two per cent) on the level at the end of 2016.
Rainfall over the catchments was 1,015mm for the year, 5.3 per cent below the long term, 30 year average.
Streamflows into Melbourne’s storages for 2017 were 405.6 billion litres, down from 476.1 billion litres in 2016 and 17.2 percent below the long-term average.
Melbourne’s water storages would be a further 3.4 per cent lower without the desalinated water received in 2017.
Melbourne Water’s General Manager, Integrated Planning, Chris Williams, said reduced streamflows were caused by a range of factors.
“Streamflow is impacted by how much rain is falling over our catchments, at what time of year, as well as the existing saturation levels of the catchment soil,” Mr Williams said.
“Steady rain over the traditional winter and spring filling season is required in order to properly saturate catchment soils and create runoff into our reservoirs.
“If rain only falls in short bursts, outside of our catchments, or if conditions are too warm, then this will limit the runoff into our water storages.
“June and July were significantly drier than average in 2017, and winter streamflows were also down, only 117.7 billion litres, compared with 190.6 billion litres in winter 2016, and this shortfall had a significant impact on storage levels,” Mr Williams said.
Melbourne’s total water consumption across all uses increased in 2017, up 31 million litres per day to an average of 1,196 million litres per day, or 2.6 percent higher than 2016.
This increase is consistent with Melbourne’s strong population growth and the drier conditions.
Storages were at their highest point for 2017 on 1 January, at 71.3 per cent full, and dipped to their lowest level of 62.0 per cent on 19 July.