Walking the dam tightrope

SOUTHERN Rural Water is in the throes of its annual balancing act, managing flows in and out of Lake Glenmaggie in anticipation of late winter and spring rains.

Water supply east manager Terry Clapham said staff were following Southern Rural Water’s release strategy which was designed to have the storage full for when demand picked up in the new irrigation season, while maintaining some storage space in anticipation of more rain.

“Glenmaggie is now at 80 percent full, up from around 50 percent before the recent rains in the catchment,” Mr Clapham said.

“Where necessary, we will release water downstream that will allow us to maintain some storage space in the reservoir in anticipation of further winter and spring rains.

“Any releases we make take into account the impacts on landholders downstream of the storage, and we minimise these impacts wherever possible.

“We are also closely following a filling curve so that the reservoir will be full when our customers need the water for irrigation.

“This is a balancing act that we perform most years with Lake Glenmaggie, ” he said.

Mr Clapham said while May rainfall was below average, June was just above average and July had begun well above average.

“July is normally our driest month, but in the first week and half we have already had 78mm in the district, and more in our catchment, against the monthly average of 37.6mm,” he said.

“With the spring period coming up, which traditionally has higher rainfall, we will be watching forecasts very closely.”

Mr Clapham said because Lake Glenmaggie was such a small storage compared with the catchment behind it, it had limited capacity to make a big difference during major floods.

“However, maintaining some storage space gives us some ability to reduce the impact of minor or moderate floods on areas downstream.”

For more information, phone Southern Rural Water on 1300 139 510.