Picture: Lake Fyans


Review of February 2017 Operations

No measurable inflow was received to any headworks reservoir for a second consecutive month during February. Year to date inflows (July – February) remain at 241,500 ML, which is 140% of the average for the same period (172,400 ML).

The volume in the headworks reservoirs declined by 19,400 ML, from 337,500 ML (60%). To 318,100 ML (57%).

Rainfall during January ranged from 15mm at Lake Wartook to 11 mm at Lake Fyans.

A Blue-Green Algae bloom was declared at Taylors Lake during February. Regular monitoring will continue, with updates available from the GWMWater website (www.gwmwater.org.au). No Blue-Green Algae blooms were detected at other headworks reservoirs during February.

(High levels of Blue-Green Algae, often referred to as a ‘bloom’, can make water unsuitable for both consumption and direct skin contact through recreational activities.)

Environmental releases continued from Lake Wartook, Rocklands Reservoir and Taylors Lake during February, with the release of environmental water also re-commencing from Lake Lonsdale to the lower Mt William Creek. A total of 152 ML environmental flow was delivered from Lake Lonsdale to Mt William Creek, and 2,858 ML from Rocklands to the Glenelg River. The MacKenzie River downstream of Dad and Dave Weir received 595 ML of environmental water from Lake Wartook, and 1,118 ML was released from Taylors Lake to the Wimmera River.

Consumptive entitlement holders collectively used 1,468 ML during January to supply urban and rural demands.

Net evaporation from reservoirs was approximately 7,800 ML for the month.

(Net evaporation considers rainfall on the reservoir as an evaporation offset.)

Planned March 2017 Operations

The Bureau of Meteorology is predicting drier than ‘average’ summer conditions over the coming three months. The Bureau’s El Niño–Southern Oscillation (ENSO) indicator has been upgraded to “El Niño watch” which indicates around a 50% chance of El Niño conditions developing during 2017. El Niño events have historically resulted in below average rainfall across south-eastern Australia.

It is expected that without significant rainfall, there will be no measurable inflows to reservoirs again during March.

Accumulated environmental passing flow commitments will continue to be delivered throughout March from Rocklands Reservoir to the Glenelg River.

Delivery of regulated environmental flow to MacKenzie River, Burnt Creek and Wimmera River is expected to continue through March. Environmental releases for the Mt William Creek are expected to continue at low ‘baseflow’ levels.

The routine delivery of water to consumptive entitlement holders will be ongoing.

The Storage Manager will continue its regular monitoring of reservoir levels, weather forecasts and waterways during March. Regular monitoring for Blue-Green Algae at headworks reservoirs is ongoing through the summer and autumn months.

Reservoirs will remain at suitable levels through March for a range of recreational activities, including boating at reservoirs where this is permitted. Please refer to the

Reservoir Level information page for further information on water levels and recreation activities permitted at each reservoir.