She told ABC radio on Tuesday night that once these approvals were met, the expected date for work to begin was May 24.

The decision by Mr Garrett has been met with criticism from the Liberal Party, Democrats and the Greens, who say the fact this announcement was made on the same day as the budget and a week late.

They said this was not good enough.

“Will he next announce the flooding of the Lower Lakes with seawater on Christmas Day?” the Member for Hammond and state Shadow Minister for the River Murray, Adrian Pederick said.

The regulator proposal was referred to the federal government on April 6, from then Mr Garrett was supposed to make his decision within 20 days, which would have been early last week.

Greens Senator Sarah Hanson-Young says the government is making a “disastrous mistake” in approving the construction of regulators around the Goolwa Channel without conducting an Environmental Impact Statement.

“Ten days of public comment, as was offered for this proposal, is not sufficient in determining the impact this will have on the short-term and long-term health of the Lower Lakes.

“An Environmental Impact Statement is a necessity for this type of dramatic intervention within an already fragile environment,” Ms Hanson-Young said.

Democrat MLC David Winderlich says the regulators will make the acid soils worse.

“The government wants weirs on the Finniss River and Currency Creek to stop acidic water from running into and polluting Lake Alexandrina,” Mr Winderlich said.

“But these weirs are between 300m and 700m long so they are going to have to dig up and disturb a lot of acidic soils.

“That will just accelerate the mixing of acidic soils with water.”

Alexandrina Mayor, Kym McHugh, acknowledges that the regulator proposal is a controversial issue, but says we must rely on the information from the scientists.

“Minister Garrett has known about this for months and months, they have obviously had a bloody good look at it,” Mr McHugh said.

He said the fact acidic water was already being mobilised showed that what the scientists have been predicting is now occurring, and if they believe an engineering solution is the only option then they should be listened to.

“I just think in this case we have to rely on the information,” he said.

“I think it is how we go forward.

“I would rather they (the regulators) not be put in but if we listen to the scientists and listen to their advice they say it should be done. The writing is on the wall I think.”