Substantial recent rain had steadily raised the water level in the estuary, giving the authorities a change to open a channel to the ocean. Once the water level rose above 1.2m, Parks Victoria and Corangamite Catchment Management Authority started testing the oxygen levels.

When an estuary is opened it is the top layer of water that flows out into the ocean, so they had to test deeper down to make sure the water that would be left in the estuary had enough oxygen to keep the fish - the ones that had survived the algal bloom - alive.

Over the weekend the testing started to show adequate oxygen levels and at high tide around 3pm on Monday, an excavator dug a trench to the sea. The water level in the estuary peaked at 1.46m, enough to make some Peterborough landowners nervous.

Heytesbury District Landcare Network coordinator Geoff Rollinson said it was a relief the river would get a chance to improve after months of devastation, but he said it would be a long road to recovery.

Locals reported the surf turning a vivid green as the river was opened and the putrid water gushed out, and the receding water left swathes of sand and wetland draped in blue-green slime.

"Thankfully the community haven't stopped advocating and we seem to finally be getting action from the authorities," he said.

Mr Rollinson said a high level Curdies River steering committee was about to be formed, led by CCMA, and including Eastern Maar Aboriginal Corporation, Agriculture Victoria, West Vic Dairy, Wannon Water, Parks Victoria, Environment Protection Authority Victoria, Department of Environment, Land, Water and Planning, Corangamite and Moyne Shire Councils, as well as five community representatives and Mr Rollinson himself.

"That committee will be looking at what actions need to be taken in the Curdies catchment and the part that each stakeholder can play in that process," he said.

It would be the first time that all parties had been in the same room and Mr Rollinson said it offered a glimmer of hope for the river.

"It's not as if nothing has been done to address the problems in the river so far, it's just nowhere near the scale of what it needs to be," he said.

"The pace of it happening on the ground has been almost glacial, really."

Mr Rollinson said since the impassioned community meetings in May where locals lambasted the inaction of the authorities, CCMA chief executive John Riddiford had been meeting with government ministers, the EPA and West Vic Dairy "to bring them all into the tent".

Meanwhile a dozen passionate locals have formed their own group to keep constant pressure on the government and authorities. Mr Rollinson said while the group was mostly composed of Peterborough residents it also had members from further upriver.

"That is important, because it is upstream that is the source of the problems," he said.

The group is due to hold its first meeting on Sunday, July 3.

IN OTHER NEWS:

Our journalists work hard to provide local, up-to-date news to the community. This is how you can access our trusted content:

Now just one tap with our new app: Digital subscribers now have the convenience of faster news, right at your fingertips with The Standard:

Have you signed up to The Standard's daily newsletter and breaking news emails? You can register below and make sure you are up to date with everything that's happening in the south-west.