Storage story positive as WaterNSW releases continue

Storage story positive as WaterNSW releases continue

09 September 2020

Storage levels in the Murrumbidgee’s two major supply dams paint a positive picture for communities recently in drought, and with a wet spring forecast, WaterNSW is making releases in preparation for future inflows.

In August, more than 470,000 megalitres (ML) flowed into Burrinjuck – the dam’s fourth highest monthly total in 10 years - with WaterNSW releasing around 110,000ML to meet extractive and environmental requirements and create further airspace for future rain events.

Burrinjuck Dam on the Murrumbidgee River has been around 82% of capacity over the past few weeks, up from 46% just weeks before. Blowering Dam on the Tumut River, which feeds into the Murrumbidgee, is at 77.6%.

WaterNSW is constantly monitoring storage levels at the two major supply dams and working closely with the Bureau of Meteorology (Bureau) to factor weather forecasts into decisions around the need for increasing airspace in the dams.

WaterNSW executive manager of system operations, Adrian Langdon, said WaterNSW river operators have succeeded in preparing for the spring rain forecast while also maintaining a steady storage level.

“As dam managers we are mindful that we cannot make releases to create airspace capacity to absorb inflows without a high degree of certainty that the anticipated inflows will replace those releases, and therefore not impact adversely on long term water security.

“The other consideration is that we don’t want to exacerbate a flood-prone river system downstream of the dam by adding too much water to the existing, naturally-occurring tributary flows.

“Conventional wisdom has it that all the water in the river originates from the dam – especially during a flood event – but this overlooks the major contribution of downstream tributaries.

Mr Langdon said that while we have seen large inflows in the previous weeks, WaterNSW is monitoring the situation carefully and significant releases have been made to prepare for a wetter than average spring forecast.

“We work very closely with the Bureau so we have access to the nation’s best weather forecasting, and we will use that information to help us decide whether to make flood mitigation pre-releases in the event of a significant rain forecast.

Media contact – Tony Webber 0428 613 478.

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