A mattress system could be used to protect the foreshore south of Oamaru Creek, at an estimated cost of $700,000.
The option will be considered by the Waitaki District Council at its meeting tomorrow as it grapples with erosion of about 400m of foreshore from the creek south to Holmes Wharf, including a blue penguin reserve, most of which has been lost to the sea.
The strip of coast can erode an average 50cm to 60cm a year, with a single storm event cutting away up to 15m.
Council water services and waste water manager Martin Pacey said that if the council approved the work, tender documents would be drawn up, then quotes called.
The council investigated options which included seawalls, an offshore breakwater and the mattress system.
Estimated costs ranged from $4.3 million for an offshore breakwater to $700,000 for the mattress system.
After assessing each option for effectiveness as well as cost, the mattress system was identified as the best.
The system uses a tubed mat, with the tubes filled with sand and joined together.
The mat is fastened at the bottom below sea level and at the top with rocks in gabion baskets.
It traps sand and fine gravel, gradually building up a gently sloping beach.
Under storm conditions, the mattress is exposed but protects the underlying slope.
It was estimated it would cost about $50,000 to replace sand and shingle over the mattress after a major storm.
