City of Wanneroo coastal hazards plan highlights vulnerability timeframe for north coast suburbs

A managed retreat approach could see the City of Wanneroo remove Sovereign Drive and houses fronting it in the future. Picture: Martin Kennealey
A managed retreat approach could see the City of Wanneroo remove Sovereign Drive and houses fronting it in the future. Picture: Martin Kennealey

HOMES and a carpark in Yanchep could be vulnerable to coastal erosion in a dozen years, according to the City of Wanneroo’s coastal hazard risk management and adaptation plan.

The plan, prepared by consultant Cardno, said the Brazier Road carpark and homes south of Yanchep Lagoon could be vulnerable from 2030.

It also said Sovereign Drive, homes in Two Rocks and Mindarie, The Spot, Capricorn groyne carpark and Karli Springs in Alkimos could be vulnerable from 2050.

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Cardno said the Brazier Road carpark, which the City recently redeveloped, and residential lots in Yanchep would be highly vulnerable by the 2050 timeframe.

“There may be overall benefit in using interim protection in this area due to the significant value of built assets,” it said.

“Any protection measure should maintain the amenity of the beach and coastal foreshore reserve.”

It recommended the City assess protection options for the Yanchep area, including managed retreat, offshore breakwaters, seawalls, groynes and sand replenishment.

In Two Rocks, Cardno said “significant public infrastructure and residential property” would be highly vulnerable by the 2050 timeframe, requiring interim protection and/or managed retreat.

“Managed retreat is likely to be triggered when Sovereign Drive requires removal due to intolerable risk or to maintain a suitable foreshore reserve,” it said.

“This would also trigger the removal of the first row of houses along the road due to loss of legal access.”

It recommended assessing the value of natural assets beside Sovereign Drive and a cost-benefit analysis of protection options as well as managed retreat in consultation with the Department of Transport, which owns Two Rocks Marina.

The coastal hazard risk management and adaptation plan said Sovereign Drive could be highly vulnerable to coastal erosion from 2050. Picture: Martin Kennealey

The consultant said residential lots north of Mindarie Marina were likely to become highly vulnerable towards the end of the century.

The report said there was no requiring government of any level to protect private property from natural hazards or provide compensation.

“In the event of coastal erosion causing a property to ‘fall into the sea’, and the land to disappear below the high water mark, the loss is to be borne by the property owner,” it said.

“Nonetheless, it is the aim of all levels of government to protect the interests of all Australians.

“The Coastal Hazard Risk Management and Adaptation Plan process ultimately intends to minimise risks.”

Cardno recommended the City notify landowners that might be affected by coastal hazards by 2120 by including a notification on property titles.

It also recommended long-term coastal monitoring and regular reviews of the plan.

Wanneroo council approved recommendations of the report at its August 21 meeting.

According to the council report, the City has spent about $8.64 million since 1999 on coastal management works, with most of the work done in Quinns Rocks.

It said the plan could impact on future subdivision in developed coastal suburbs and new or proposed developments, as well as redevelopment plans for Quinns Caravan Park and Yanchep Lagoon.