Plans for additional environmental upwater are based on flawed assumptions

It used flows that have since been significantly reduced, due to the impacts that would have resulted from the subsequent major flooding.  

In early 2012 a workshop of experienced river operators was requested by the Basin Official Committee “to embrace ‘blue-sky’ thinking, and not to be constrained by current arrangements.”

The workshop focussed on investigating  how to increase the frequency of overbank flows in the Lower Murray to achieve a target event of up to 80,000ML/day downstream of Euston for up to 30 days every 1:4 to 1:5 years.

To achieve this target event the workshop analysis stated the key features required  were significant inflows from at least three of the four major river systems, relaxation of constraints, pre-wetted (primed catchments) with timing of inflows from each catchment being crucial.

As  blue sky thinking is “not grounded or in touch with realities of the present and does not include the necessity of dealing with practicality,” the workshop concluded that increased environmental flows were feasible if constraints were relaxed, but in reality had no knowledge if constraints could in fact be ‘relaxed’, only noting socio-economic impacts would increase with higher  flows.

The MDBA in its hydrological modelling of the relaxation of operational constraints in the southern connected system October 2012 assumed a relaxed constraints scenario was possible and used flow levels that have since been abandoned due to the severe impacts that would be caused by the major flood flows that would be needed to achieve a flow of 80,000ML/day at the South Australian border.

To achieve this flow the MDBA modelling used a flow of 40,000ML/day in the Lower Goulburn now reduced to 20,000ML/day  and 40,000ML/day in the Yarrawonga to Wakool  Constraints area, now reduced to 30,000ML/day.

Despite this reduction in flows there has never been any revised modelling or analysis to assess the fact that these reduced flows mean the 450GL cannot be delivered in the initial proposed large volumes to South Australia.

The Experienced River Operators  workshop did however note that a cost/benefit analysis would be needed and  the following significant issues would need resolving:

·         Easements and inundation of private property

·         Legal liability

·         Impacts on water entitlements and irrigation delivery entitlements

·         water policy issues such as carryover and water accounting

·          weather forecasting

·         Improved real-time  gauging of rivers, rainfall and run-off

·         ownership and maintenance  of levees

·         integrated operational  policy across catchments and basin states

Six years later, despite the MDBA also stating in 2012 ,  that a cost/benefit analysis  would be required,  there has been no cost/benefit analysis undertaken.  

None of the above  issues have been resolved.

But the Federal Department of Agriculture and  Water Resources are rushing forward with the attempted recovery of the 450GL, despite the fact they have no certain knowledge or scientific grounds to show that this water can be delivered downstream within the legislated guidelines of not causing adverse or negative socio-economic impacts, or that the additional water, under the current flow reductions in the Goulburn and Yarrawonga -Wakool area, can achieve the proposed enhanced environmental outcomes such as  keeping the Murray Mouth open 95per cent of time without the need for dredging.

There are many intractable problems associated with the recovery of the  450GL and its delivery, via a constraints strategy.  

The entire concept is delusional and fanciful, based on outdated modelling  and ‘blue sky thinking’ which is simply not bounded by reality.

 We are yet to see any analysis and documentation showing that it is  technically and practically feasible, viable and realistic to recover and deliver the additional 450GL.

Jan Beer

Cheviot Hills, Yea