A regional council facing a massive bill after the removal of about 500 submerged shopping trolleys says it is willing to impose financial penalties if major retailers Woolworths and Coles don't agree to fork out the bulk of the cost.

Key points: Removal of the trolleys from beneath Port Augusta wharf began last year

Removal of the trolleys from beneath Port Augusta wharf began last year It was expected to cost $15,000 but that has almost tripled because of delays

It was expected to cost $15,000 but that has almost tripled because of delays Negotiations over who foots the bill will continue this week

The Port Augusta City Council in South Australia's north began removing the trolleys from the base of the local wharf in the Upper Spencer Gulf last year, amid longstanding concerns over community safety.

It had issued notices warning locals not to jump from the wharf into the water because they risked "serious injury".

Some piles had reached up to six-metres-high prior to their removal, with trolleys able to be seen just beneath the surface of the water.

The scale of the issue was identified during diving surveys of the area in July last year.

The removal was expected to cost $15,000 with the bill to be jointly covered by the council and the city's major supermarket chains Woolworths, Coles and Big W.

But a number of delays blew out the expected final cost to $40,000, with negotiations over the payment to begin this week.

Piles of shopping trolleys off Port Augusta's wharf before the removal. ( Supplied: Christopher Pollard )

Port Augusta City Council's city services director Melissa Kretschmer said if the stores chose not to pay the agreed amount, the council could act.

"We do also have the option, which we'd ideally not have to go down, but we can actually fine these organisations for the illegal dumping of their goods," she said.

"So it would not have to be a cost worn by the council. We've had a great working relationship with the supermarkets so we're hoping that we won't have to get to that point."

Trolley removal delayed by weather and crane fault

Under South Australian law, areas below the high-tide mark are considered the responsibility of the State Government.

But Ms Kretschmer said it had already been agreed the city's three major stores would cover 90 per cent of the removal cost, with the remainder to be covered by the council.

The shopping trolleys were dumped in the water years before being removed. ( ABC North and North West: Gary-Jon Lysaght )

She said the council had only recently received final invoices for the work and would now look to negotiate payment with retailers.

"We now have to go back and ask for twice as much," she said.

"They've been very cooperative to date with their involvement in the project, so I remain hopeful that we will have a positive outcome.

"We agreed to contribute 10 per cent because some of the items that were submerged weren't shopping trolleys — it wasn't all the property of the supermarkets".



The removal was initially delayed by a crane breakdown, before high winds forced the first retrieval to be abandoned late last year.

Site workers used high-pressure cleaners to remove barnacles and algae. ( ABC North and North West: Gary-Jon Lysaght )

Initially, divers piled the trolleys on the seabed alongside the wharf, before they were connected underwater and hoisted ashore.

Most of the trolleys were covered in barnacles and seaweed, but others were almost spotless, indicating the dumping by members of the public had been an ongoing issue.

After the first contractor returned for another day's work, the removal was completed by a second company contracted to demolish a jetty near the wharf this year.

The remaining trolleys — about 250 — were retrieved from the water using a barge.

"It's doubled the cost because the second contractor spent an extra two-and-a-half days on site removing the trolleys and then transporting them off," Ms Kretschmer said.

"It was reasonable to expect that another two days was needed onsite because of the number of trolleys left."

Wheel locks introduced to prevent dumping

Ms Kretschmer urged the public to keep their safety in mind and also consider the impact of their actions.

"It is still illegal to jump off the wharf, it is shallow there at the best of times," she said.

"Keep in mind the overall impact on the community [of dumping trolleys]".

The shopping trolleys were recycled by contractors employed to remove them. ( ABC North and North West: Gary-Jon Lysaght )

Coles and Woolworths declined to comment on whether they would still pay 90 per cent of the $40,000 cost.

A Coles spokesperson said it had been proactive in installing wheel locks "on all trolleys at our store to limit their movement beyond the store perimeter".

"Coles is continuing to work with the Port Augusta City Council and other retailers to recover the trolleys removed from our stores and awaits an update on the next steps."

A Woolworths Group spokesperson said it would "continue to invest heavily in regular trolley collection services".

"We have committed significant funding to help retrieve the submerged trolleys, so it's disappointing to see the project hasn't succeeded as yet," the spokesperson said.

"We're open to further discussions with the council on this matter."

Port Augusta is the most northerly city with ocean access in South Australia.

Much of the city's marine infrastructure faces an uncertain future, including its heritage-listed wharf, which has fallen into disrepair.

Marine engineers estimate repair costs for the wharf at $11 million.