BOULDERS will be used in a bid to stop further erosion of cliffs at Mt Martha Beach North and damage to the Esplanade.
Engineering consultants have warned that the ongoing loss of the cliffs between Alice and Augusta streets threatens to eventually damage the coastal road linking Mornington and Safety Beach. The bitumen is cracked in many sections of the road which has also been closed twice in recent years because of landslides
Work on installing rocks at the cliff base will start in April, although 430 metres of the beach is likely to remain officially closed until the project is completed.
The Mt Martha North Beach Group sees the rock revetment going only “some way towards solving our problems”.
Members of the beach group believe a 25 metre long rock groyne should be built north of the beach to prevent further loss of sand. Consultants have put a $330,000 price tag on the groyne (“Call to make a point” The News 5/12/18).
In the weeks leading up to Christmas five beach boxes were demolished, while others remain on precarious stumps.
Access stairs to the remaining beach boxes end high above the sand, giving an indication of how much of the beach has been swept away. Steps to the beach opposite Alice St are closed.
The cliff continues to crumble behind the boxes making them vulnerable to landslides as well as to being knocked down by the sea.
Environment Minister Lily D’Ambrosio says while $880,000 will be spent protecting the base of the cliff the Department of Environment, Land, Water and Planning (DELWP) will have a closer look at “engineering solutions” to prevent further erosion of the beach and cliff (“Beach ‘repairs’ could cost $4m” The News 31/10/17).
Mornington Peninsula Shire – in a news release welcoming the state government’s intervention – points out that it only manages the beach which is owned by DELWP.
“Significant erosion and wave action over a number of years has caused damage to the land and buildings located on the foreshore resulting in unstable cliffs,” the shire states in its news release.
“The rock revetment (or sloping rock wall) will protect the cliff toe from waves and erosion, and maintain public safety from cliff deterioration. The revetment will help prevent damage to public assets and infrastructure behind the cliff, including the Esplanade.
“The revetment will extend south 140 metres from the southern end of the existing revetment. A further 60m of revetment may also be constructed north of the access stairs.”
The mayor Cr Bryan Payne said the rock revetment “is vital to improve public safety near the cliff area following erosion over the years”.
“We thank the state government for working hard to get the cliff stabilised and the beach safe to get it reopened for public use as soon as possible.”
Consultants Water Technology was hired by DELWP to study erosion at Mt Martha Beach North following two severe storms in winter 2016.
Their options – subject to an “options analysis by DELWP later this year – ranged from the $330,000 rock groyne to $4 million.
Nearly 13,000 cubic metres of sand trucked in to replenish the beach in 2010 was lost within three years.
The DELWP consultants said the remaining beach boxes may need to be removed during work to stabilise the cliffs.
First published in the Mornington News – 16 January 2018
