Review of December 2017 Operations
No measurable inflow was observed to reservoirs during December. Between July and December 67,250 ML of inflow has been recorded into headworks storages, which is 40% of the historic average for the same period (166,300 ML).
During December, the volume in headworks reservoirs decreased from 351,490 ML (62.8%) to 331,190 ML (59.2%).
Rainfall was below average at all reservoirs during December. The highest rainfall for the month was 29mm, recorded at Moora Moora Reservoir.
Environmental water releases from Lake Wartook continued during December with 373 ML supplied from Lake Wartook to the MacKenzie River. Lake Lonsdale supplied 757 ML via Mt William Creek to the Wimmera River. Rocklands Reservoir continued to supply passing flow obligations to the Glenelg River during December, with 1,353 ML released from the reservoir.
Wimmera-Mallee Pipeline supplied Recreation Lakes received 110 ML during the month, and 2 ML was supplied to wetlands within the Mallee and Wimmera Catchment Management Authority areas.
Consumptive entitlement holders collectively used 1,515 ML during December to supply urban and rural demands.
Due to below average rainfall, net evaporation from reservoirs was approximately 8,000 ML for the month; with evaporation exceeding rainfall, (Net evaporation considers rainfall on the reservoir as an evaporation offset).
Planned January 2018 Operations
The Bureau of Meteorology (BoM) in their most recent climate outlook predict a 50% chance of above average rainfall this January. Pacific Ocean climate patterns indicate that weak La Niña conditions are continuing in the tropical Pacific. BoM expect this La Niña event will be short-lived and decay during autumn 2018. La Niña events have historically brought above average rainfall to south eastern Australia during late spring and summer, however the weak nature of the current La Niña conditions mean that there will be less influence on rainfall. La Niña events can also increase the likelihood of prolonged warm temperatures.
No water transfers are currently planned for January, however the Storage Manager will continue to monitor conditions. Further information in relation to water transfers are described in the Storage Manager’s Annual Operating Plan.
The release of environmental water and the routine delivery of water to consumptive entitlement holders is expected to be the Storage Manager’s operational focus during January.
Reservoirs are expected to remain at suitable levels through January for a range of recreational activities, including boating at reservoirs where this is permitted. Please refer to the Reservoir information page for further information on water levels and recreation activities permitted at each reservoir.
Blue-Green Algae blooms can be more common during the warmer summer months. Recent Blue-Green Algae warnings for reservoirs can be found on the Storage Manager News Feed and all current warnings are available from the GWMWater Algae Warnings webpage.