Can Basin Plan pass nature’s test?

Can Basin Plan pass nature’s test?


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Riverina floods raise questions over viability of environmental goals

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IT IS the flood that proves the Murray Darling Basin Plan won’t work, Riverina locals say.

Frustrated farmers caught in the inundation around Deniliquin and beyond argue current flooding shows that the amount of water to be recovered for the environment by the Murray Darling Basin Plan will not physically flow down the river without breaking banks and causing significant damage.

“The proof is in the pudding. These natural floods have confirmed what we’ve been saying for years,” said Southern Riverina Irrigators spokesperson, John Lolicato.

Mr Lolicato and fellow local farmers Andrew and Louise Burge are leading a push among landholders in the Yarrawonga to Wakool region, upstream from Deniliquin and downstream from Hume Dam.

They’re at loggerheads with the Murray Darling Basin Authority (MDBA) over the Plan’s proposed Constraints Management Strategy – similar to a network map of the Southern Basin with flow rates at various points in the system.

It’s designed to deliver water to South Australia, the wetlands and other environmental sites along the way, but Mr Burge said the current floods demonstrate the flows mapped out by the strategy would be “too risky and expensive”.

The MDBA’s proposed flow rates have been wound back to a maximum of 65,000 megalitres per day downstream of Yarrawonga, which was said to be safe, achievable and well below the recent peak flow of 175,000ML/day (see page right). 

Mr Burge said allowing 65,000ML through Yarrawonga each day strategy would “prime the system to be just one rainfall event away from a major flood”, if joined by unregulated flows from the Victorian tributaries.

NSW Department of Primary Industries is reviewing the strategy. A spokesman said the starting point for flow rates should be “well below” 65,000ML/day. Monitoring of current floods will be used to “inform future business cases by using real events, rather than MDBA models”, the spokesman said. 

While the landholders agree that returning water to the environment should continue, Mr Burge said they won’t accept impacts from “an undeliverable plan designed for political imperatives” during the Millennium drought.

Mr Lolicato said even during the current floods, the Basin Plan’s flow targets at the South Australian border had not been achieved.

“We’ve had flows of 100ML/day downstream of Yarrawonga for five weeks and the country between Hume Dam and the Wakool Junction (with the Murray River) is a sheet of water. But look at the flows at the SA border. It’s only hit 48ML/day,” Mr Lolicato said.

“Nature has provided us with the trial and its shows we can’t reach the target without significant damages.”

Mr Burge said the MDBA, which oversees management of Hume Dam, had shown it was “incompetent” with its flood management. Incremental releases should have been made, as inflows poured into the storage during the wettest September on record, to remove the need to send “the wall of water” downstream which inundated land below the dam with “catastrophic flooding between Tocumwal and Deniliquin”. 

Prioritising water storage for irrigation was unnecessary given the forecast inflows, he said.

But MDBA head of river management David Dreverman said Hume must be operated “to ensure there is a very high chance the storage will fill”.

“The MDBA manages the dam to maximise the amount of water in storage second only to ensuring safety of the dam itself. Within those bounds, we also adjust releases to limit flooding… it’s the rain that causes the flood, not the dam.

“The recent flooding that occurred downstream will happen again – it’s only a matter of when.”

DESPITE outspoken criticism from local landholders, the Murray Darling Basin Authority (MDBA) says proposed flow targets to deliver water to the environment do not pose significant risks.

Enviro flows no flood threat

MDBA head of river operations David Dreverman said peak spring flows of 175,000 megalitres per day downstream of Yarrawonga, Victoria, were nearly triple the 65,000ML/day figure put forward in the Constraints Management Strategy, is now under review by NSW government.

“Current flows in the river are the result of persistent and heavy rainfall and flood operations at Hume Dam, which are very different to the circumstances under which environmental water would be released for the (strategy),” Mr Dreverman said.

“In the majority of years in which operators would release environmental water, once the (strategy) was implemented, the early release of water from Hume Dam would create air space that would be available to mitigate any later season flooding.”

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