A project to combat coastal erosion by depositing thousands of cubic metres of sand at Fremantle’s Port Beach is set to commence in the coming weeks.
The Port Beach Sand Nourishment Project will see up to 150,000m3 of sand dredged from Fremantle Port’s Deep Water Channel and ‘rainbowed’ onto the beach.
Rainbowing involves the pumping of a mixture of dredged sand and water through a hose with a nozzle, into a high arc through the air and onto the nearshore area.
Subject to final safety plans being approved, an initial placement volume of around 30,000m3 of sand is expected to be placed on the beach over a two-week period, with the remaining up to 120,000m3 to be placed during 2023.
The project is being delivered as a partnership project by the City of Fremantle Council, Fremantle Ports and the Department of Transport using $3.25 million in WA Recovery Plan funding from the WA Government.
Fremantle Mayor, Hannah Fitzhardinge said the sand nourishment program would provide a buffer to protect landward assets against the effects of coastal erosion while also providing public amenity.
“In a report released by the state government in 2019 Port Beach topped the list of WA’s coastal erosion hotspots,” Mayor Fitzhardinge said.
“The design of the Port Beach sand nourishment program has been developed to provide a wide enough beach so that, with the anticipated movement of the placed sand, there will still be a sufficient buffer against the erosion caused by severe storms.
“We’re very glad to be able to partner with the state government to deliver this project for a beach that is highly valued by locals and visitors alike.”
Fremantle Ports CEO, Michael Parker said while protection of the beach for the public was paramount, the sand renourishment had operational advantages as well in terms of maintenance of the shipping channel’s depth and ensuring a buffer for the critical Port Beach Road access to Rous Head.
The present pattern is for eroded sand from Port Beach to be transported to the north and deposited near Leighton Beach. In a bad year Port Beach can lose up to 40,000m3 of sand, however the average annual loss is around 15,000m3.
The works are intended to provide protection for up to 10 years, although the actual life of the works will ultimately depend on the weather conditions experienced over the next decade.
Some of the placed sand is expected to migrate northwards over time. Council says a shoreline monitoring program will be implemented to track the movement of the placed sand, and if significant movement occurs additional maintenance or nourishment works may be required.
Sand nourishment via dredging was selected over other potential coastal erosion adaptation options based on the investigations and recommendations of coastal engineering experts in 2019.
