Water authorities have been contacted regarding the damage to banks and habitat along the Goulburn River from high summer flows.
A Greater Shepparton City Council motion was last month endorsed at the Murray-Darling Association’s national conference, calling for water ministers and authorities to investigate the environmental impacts of running commercial water down the Goulburn River during summer periods.
MDA chief executive Emma Bradbury said Victorian Water Minister Lisa Neville, the Murray-Darling Basin Authority and catchment management authorities had been called on to ‘‘undertake a detailed and holistic review’’ into the practice.
Cr Dennis Patterson last month said he was concerned that longer periods of higher water in the Goulburn River was causing significant damage to river banks and habitat and called for action to be taken.
Key arguments outlined ahead of the conference detailed that in February the river had risen about 1.5m above its normal summer level, and stayed at this height for about two months, ‘‘destroying all the ground cover that had benefited from an environmental flow during spring 2017’’.
Goulburn Broken Catchment Management Authority chief executive officer Chris Norman said inter-valley transfers — water traded between different systems, such as between the Goulburn and the Murray — had started earlier than usual this irrigation season.
‘‘To minimise the effects on the river’s banks and vegetation caused by a constant flow, we’ve worked closely with Goulburn-Murray Water and the MDBA to ensure that the inter-valley transfers are delivered along the Goulburn River as a variable flow,’’ Mr Norman said.
Goulburn Broken CMA said that as river systems were now highly modified, environmental water managers did not aim to return rivers to ‘natural’; rather they aimed to time delivery to protect specific sites and species at key times in the breeding and growing cycle.
A flow starting on Monday, September 24 will see a planned volume of around 140000Ml flow down the river, with about half of this volume expected to be provided by environmental flows and the remainder by inter-valley transfers and passing flows.
The water from Goulburn Weir will ‘top up’ inter-valley transfer deliveries, which are currently between 500Ml/day and 3000Ml/day.
This extra water will see river flows peak around 8500Ml/day (a river height of about 4m) on Friday, October 5.
Goulburn Broken CMA said this was well below minor flood level and, in the event of heavy rain, the flow might be smaller or not go ahead.
The meeting background document argued the river was in ‘‘far worse condition than before the environmental flows started,’’ citing ‘‘mud slipping into the river from the bare banks and those bare banks exposed to wave erosion’’.
‘‘Inter-valley water transfer was never to be done with any detriment to the river but clearly this is not the case. This has to be reversed immediately,’’ the document said.