The North Central Catchment Management Authority says years of managing water for the environment, fencing off stock and revegetating the river bank have helped restored the river.

"While the river is still recovering from the Millennium Drought and the 2010-11 floods, it is well on the way to recovery," NCCMA environmental flows project manager Darren White said.

"Over the past 18 months we have seen amazing native fish numbers in the river downstream of Eppalock, with large Murray cod and golden perch being caught regularly, and even good numbers of the critically endangered silver perch being recorded.

"We have evidence of Murray cod spawning for the second year in a row, which has never been recorded before, and Murray Darling rainbowfish returning after being hit with high irrigation flows last summer.

"You can't catch the rainbowfish, but they're great food for larger natives."

A lack of flows this year has seen leaf litter build up, which means up to 1400 megalitres of water a day will be released into the river for three to four days next month to flush it out.

This aims to prevent any toxic blackwater events in summer, which occur when organic materials break down and cause oxygen levels to drop, sometimes leading to fish deaths.

Mr White said the flows would also encourage native fish to start moving and looking for mates.

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