While about two thirds of the reservoirs within GWMWater’s catchment remain at 50-per-cent capacity or greater, Lake Wartook in the Grampians is at its lowest start-of-December volume since 2008.

It sits at 62 per cent capacity, down from 94 per cent at this time last year.

Lake Lonsdale currently has the lowest water volume percentage-wise of the nine reservoirs in the Grampians Wimmera Mallee catchment, with 26 per cent. This time last year, Lonsdale was 64 per cent full.

At the other end of the scale, Lake Bellfield is at 82 per cent capacity, Taylors Lake at 76 per cent, and Lake Fyans at 78 per cent.

GWMWater water resources manager Kym Wilson said the diminished levels were a product of below-average winter and spring rainfall and inflows.

“In terms of the reservoir system, inflows for the water year to date – from July 2018 – are about 22 per cent of the historic average,” he said.

“I wouldn't say the storage levels are anywhere near historically low levels. They're within the range we've seen in the past two to three years.

“With the below-average rainfall over winter, we've seen recovery being less than previous years.”

Swimming is permitted at each of the reservoirs except Lake Wartook, while fishing and boating – in various forms – are permitted at all nine reservoirs in the catchment.

In September, GWMWater’s board announced a top-up for Green Lake near Horsham, which will ensure the lake is at a level sufficient for sailing and water-skiing this summer.

Reserve levels in the authority’s water holdings allowed for the transfer.

Board chairman Peter Vogel said at the time GWMWater was fortunate to have more than four years’ reserve in its holdings from the Grampians headworks system based on current demands for water.

Mr Wilson said the authority had transferred some water earlier in the year from Rocklands to Toolondo, consistent with its operating plan, and also transferred water from Lake Bellfield to Lake Fyans.

“Dependent on the conditions over summer, there are provisions for a transfer to Lake Fyans in the March to early April period,” he said.

Mr Wilson encouraged people taking advantage of the region’s lakes and waterways for swimming, boating or fishing during summer to do so with care.

“We encourage that people follow any signage on site that might restrict activities, such as the presence of blue green algae,” he said.

An algae warning for Edenhope’s Lake Wallace was lifted last week.