No airspace in dams coming into spring worries landholders

Saturated catchments and a LaNina event have landholders along the Murray worried about floods as Dartmouth Dam sits at 99 per cent.

Authorities have failed to use a flood-saving mechanism that landholders say could prevent flooding this spring.

With Hume Dam sitting at 96 per cent yesterday (Tuesday) and Dartmouth Dam at 99 per cent, there are fears those along the Murray River could be flooded with the next big rain event. The Dartmouth Dam is teetering on spilling, which would be the first time it spills since 1996.

Deniliquin farmer Louise Burge said up to 13 per cent of Hume Dam could be used to manage extreme floods, or about 386 gigalitres of air space.

“Dartmouth is on the brink of spilling, Hume Dam is almost full, there are high flows down the Darling and this all means abundant water to meet all irrigation allocation needs,” Ms Burge said.

“However, the Murray Darling Basin Authority is managing the Hume Dam on a model that makes predictions on “lowest sequence inflows” for every year over a 114 or so years.

“The model assesses worst case inflow scenarios instead of actual reality conditions.”

Ms Burge said flooding in 2016, which she described as “catastrophic”, were caused after dam managers ignored a Bureau of Meteorology forecast of 100mm and relied on a model developed during drought.

“The MDBA ended up dumping 20 per cent of Hume Dam in one week causing such levels of flooding the Central Murray Floodplain Plan failed,” Mrs Burge said.

“This year’s risks are even worse as most major storages in the Southern Basin are nearly full.

“It beggars belief that politicians and bureaucrats are not utilising an airspace rule available to them to help mitigate a flood disaster in the Murray Valley.”

Murray Valley Action Group chairman Richard Sargood said he had pleaded for a common -sense approach.

The group represents about 130 farmers between Hume Dam and Yarrawonga Weir and participates in weekly hook ups with the MDBA.

“Where possible the extremes of flooding risks should be mitigated and this can be done without impacting the security of irrigation water,” Mr Sargood said.

In its weekly update on the Murray River, the MDBA said operations at Hume Dam in recent weeks had been “focused on careful airspace management to balance the need

to fill the storage prior the emergence of significant downstream demands with the need to maintain some airspace to help mitigate, where possible, the passage of any flood events that occur upstream”.

“Hume Dam airspace management and flood operations so far have provided significant flood mitigation for downstream communities with high inflows and moderate flooding in the upper Murray managed with releases at rates below minor flood level at Albury Downstream at Corowa, the river remains at the minor flood level.”