Airspace at Glenmaggie averts minor flooding

MAINTAINING airspace in Lake Glenmaggie has allowed Southern Rural Water to keep downstream flows over the last few days to below minor flood level.

SRW east water supply manager Terry Clapham said heavy rainfall in the catchment late last week saw flows into Glenmaggie jump to as high as 17,400 megalitres per day last Friday afternoon.

“However, because of the airspace available in the reservoir, we were able to hold our downstream releases to just below minor flood level at about 7200 ML/day,” he said.

As a result, the reservoir climbed from 91 to 97 per cent full.

“Glenmaggie only has limited capacity to affect flood management, because it is such a small storage on such a large catchment,” Mr Clapham said.

“However, the last few days have demonstrated that the storage can have an effect during minor floods.

“We are acutely aware of the economic impact floods can have on pastures and vegetable crops – our aim is always to reduce flood impacts as much as possible in balance with our responsibilities to manage the storage safely and retain water for irrigation.”

Mr Clapham said SRW was releasing higher than normal flows to manage the level of the reservoir in anticipation of further autumn rains, with the aim of building airspace of about 20,000 ML.

SRW posts updates on its website any time downstream releases are above 3500 ML/day.