A Murray Bridge earthmoving contractor has been fined $26,000, plus prosecution costs, for carrying out unauthorised work at White Sands in 2016.
The Environment Protection Authority (EPA) and the Murray Bridge council took Stewart Andrew Morgan and his company, SA Morgan Pty Ltd, to court for carving out a hill on a property he owned and dumping the dirt into the Tobalong wetland.
Mr Morgan deposited up to 5400 tonnes of soil onto native reeds along the edge of the River Murray, thinking they were just weeds.
That caused environmental damage that the EPA argued was "not trivial", and also disturbed an ancient Aboriginal shell midden.
No council approval was obtained for the work, which took place below the 1956 flood line.
Authorities learned what was going on when several residents complained, as The Standard reported at the time.
Interesting afternoon down at White Sands, chasing a potentially illegal development. Big works going on down here. Neighbours aren't happy.— Peri Strathearn (@PeriStrathearn) February 25, 2016
A legal dispute followed as the EPA directed Mr Morgan to remove the dirt from the wetland, but Mr Morgan and an environmental consultant argued that leaving it in place and planting it with native species would be good enough.
However, Mr Morgan ultimately failed to comply, and the matter returned to the Environment, Resources and Development Court last month.
Judge Jack Costello said Mr Morgan had not been reckless, as he did not know he was doing anything wrong.
"I accept that he is very remorseful and that there is little, if any, likelihood of him offending in this way again," he said.
"Whilst general deterrence remains an important factor ... I do not overlook the fact that these earthworks were carried out in ignorance of the environmental significance of the wetlands."
However, he was still found guilty of two offences - one for failing to get development approval and one for failing to comply with the enforcement notice - and fined $26,000.
He was also ordered to pay a victims of crime levy and the prosecution's costs, totalling about $2500.
A conviction was recorded against SA Morgan Pty Ltd.
The site clean-up is likely to cost more than $40,000, and must be completed by May 31 unless the parties agree on an extension.