Popular beach predicted to shrink by 12 metres as tides rise

By Caroline Horn

ABC South East SA

Topic:Erosion

Mayor Keith Parkes is also chair of the South Australian Coastal Councils Alliance. (ABC South East SA: Caroline Horn)

In short:

It is predicted that Horseshoe Bay at Port Elliot in South Australia will erode by up to 12 metres by 2050 if significant engineering work is not undertaken.

Repairs to the breakwater, seawall and sand replacement are options being considered.

What's next?

Mayor Keith Parkes says the state government will need to provide funding.

There are fears the shores of an iconic South Australian beach will continue to erode if more than $20 million in engineering works is not undertaken.

Projections have shown Horseshoe Bay at Port Elliot, one of South Australia's most visited regional beaches, could be further eroded by up to 12 metres by 2050 from rising tides.

The picturesque beach falls within Alexandrina Council, an area that includes the towns of Port Elliot, Middleton, Goolwa and Strathalbyn and has a population of about 31,500.

A report prepared for the council set out a number of options, including repairing and extending a damaged 1850s constructed breakwater.

There are five possible options being considered by council to address erosion. (Supplied: Alexandrina Council)

Mayor Keith Parkes said work on the breakwater would need to be done in conjunction with repairs and extensions to the existing sea wall, as well as sand replacement, potentially from an external source.

He said while the council deliberated over which actions to take, one thing was clear.

"We're talking about 12 metres by 2050 if nothing's done."

The seawall is now being temporarily protected from the waves by concrete blocks and sandbags after being damaged by storm water. (ABC South East SA: Caroline Horn)

The bay is tucked along a popular surfing coastline and its relative safety is a drawcard for families. It is a site for learn-to-swim programs in the summer.

The local caravan park is nestled behind dunes at the southern end while the sea wall stands between the local bowls club, a cafe and playground equipment.

"It's a very, very popular spot and it's a great tourist attraction for the state," Cr Parkes said.

The breakwater was first constructed in the 1850s and was originally intended to reach nearby Pullen Island. (ABC News: Bec Whetham)

Under the South Australian Coast Protection Act, councils carrying out works to protect, restore or develop any part of the coast can apply to the state government's Coast Protection Board for a grant to cover up to four-fifths of the cost.

However, Cr Parkes said Horseshoe Bay was only a small part of Alexandrina's 26 kilometre-long coastline and his council was only one of many facing ongoing expensive issues.

Logistical challenges

Cr Parkes' preference is to repair the breakwater as soon as possible, along with upgrades to the seawall and sand replenishment from an external source.

The breakwater was originally constructed in the 1850s to try to protect ships taking on cargo at the small port. (ABC South East SA: Caroline Horn)

The logistics, however, could be complicated.

"It sounds like a simple, straightforward thing: put some more rocks on the breakwater and fix it, but it's getting the rocks to the breakwater," Mr Parkes said.

The current breakwater stretches from Lady Bay, a small sandy cove at the bottom of the steep rocky cliff on the southern side of Horseshoe Bay.

Sand nourishment using external quarry sand, or moving sand from the southern end of the beach, is also being considered. (ABC South East SA: Caroline Horn)

It was completed in 1855 using rock from the cliff face to provide protection for ships visiting to load cargo. However, four ships were wrecked in the bay in 1856 and the port was abandoned for shipping purposes in 1866.

The bay's seawall was installed in the 1930s, with parts of it replaced about 40 years ago. It was recently damaged by stormwater after two heavy rainfall events and is currently partially fenced off and has had large concrete blocks placed in front of it as a temporary buffer.

Part of the seawall collapsed during heavy rain on August 9. (Supplied: Belinda Sullivan)

Cr Parkes said any work to undertake sand replenishment would have to be done in a way that had the least impact on the beach and surrounds.

Finding the money

Increasing the height and length of the breakwater was projected in 2025 to cost about $18 million.

Sand nourishment could cost as much as $1.5 million annually and repairs and extension of the seawall between $3 and $4 million.

Beachgoers at Horseshoe Bay at Port Elliot circa 1920. (Supplied: State Library of South Australia)

A federal parliamentary committee enquiry into the financial relationship between local government and other levels of government in Australia is currently hearing submissions on funding mechanisms and fiscal sustainability.

The Alexandrina Council is one of several that believe the assessment process for funding grants needs to better recognise the cost of maintaining tourism areas and protecting coastal assets against climate change.

Lou Nicholson was elected as the MP for Finniss in March but was previously a councillor with the Alexandrina Council and is familiar with the bay and engineering proposals.

She agreed with Cr Parkes that there was a need for communication around the increasing costs being faced by local government.

Lou Nicholson, Independent Member for Finniss, at Horseshoe Bay in Port Elliot. (ABC South East SA: Caroline Horn)

Alexandrina Council voted in July to defer any decision about the future of Horseshoe Bay until a workshop to discuss the entire 26km of council coastline could be held.

A spokesperson from the Department for Environment and Water said Alexandrina Council was responsible for the management of the Horseshoe Bay breakwater and that no application for funding had yet been received.

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