The annual early spring environmental flow along the lower Goulburn River will not go ahead this year because of recent high natural river flows.
“For the past five years we’ve delivered higher flows along the Goulburn River below Goulburn Weir in spring, once it starts warming up, to help re-establish bank-stabilising vegetation that declined after years of drought followed by major floods in 2010 and 2011,” Goulburn Broken Catchment Management Authority (CMA) CEO Chris Norman said.
"We’ve had to deliver this extra – environmental – water in previous years to the lower Goulburn River as it had been relatively dry and Goulburn River winter flows upstream of Goulburn Weir were diverted and stored at Waranga Basin to meet irrigator and other water users’ demand. After a very dry year, fortunately nature has given the lower Goulburn River a helping hand, mainly through run-off and inflows from the Broken River and the Sevens, Castle and Pranjip creeks following heavy rain during July and August.”
These inflows saw the Goulburn River peak at 9.4m at Shepparton, below the minor flood level of 9.5m, on August 4.
“In addition to boosting soil moisture and providing a good environment for in-stream and river bank plants, the higher flows are also good for fish, birds and other animals, as well as the water bugs that are an important source of food for native fish and platypus,” Mr Norman said.
Without significant rain, river levels are expected to stay around current levels (about 3m at Shepparton) for the rest of the month. This is because water is being released from Goulburn Weir now that Waranga Basin is close to capacity, as well as from run-off and inflows from tributaries.
“Monitoring shows that thanks to previous years’ environmental water deliveries, the right kinds of plants are starting to grow and spread on the river banks,” Mr Norman said. “However, too much inundation is as bad for bank vegetation as too little. Bank slumping is also more likely in wet years when the soil profile is saturated, as it is right now. So, given the natural higher flows have already achieved what the planned spring environmental flow was aiming to do, we will not go ahead with the delivery this year.”
This is not the first time an environmental flow has not gone ahead. In 2014, a winter flow did not occur after heavy rain and last year a November delivery was cancelled due to low water allocations.
“It’s standard practice for the agencies involved in delivering and planning the flows to adjust yearly watering plans in response to prevailing weather and river conditions and other water users’ demands,” Mr Norman said.
Goulburn River level and flow information can be found at https://waterline.g-mwater.com.au/waterstatus/ and at www.g-mwater.com.au/managing-water-storages For more information about the planning of environmental releases in the Goulburn River visit www.gbcma.vic.gov.au/projects/environmental-water
or phone (03) 5820 1100.
The Goulburn Broken CMA prioritises environmental water releases in line with the Victorian Environmental Water Holder’s annual seasonal watering plan.