Third-year master of science student Tom Simons-Smith (23) spent the past year measuring the build-up of sand in three notches carved in the dunes below John Wilson Ocean Dr to encourage dune growth.
Mr Simons-Smith said his project had been more successful than other recent attempts to fight Otago coastal erosion, and he hoped councils across the region would adopt the method.
In April, he said the dunes were at risk of being eroded by "one big storm". Results from his project revealed 80cum
of sand had been moved through the notches by wind to buffer the road from the ocean.
The project cost $1000, and if replicated on a larger scale could save ratepayers significant money and vastly improve the future of Otago’s coastline, he said.
"In the long term, it’s not going to save the South Dunedin area, but it will buy time.
"In the end, I think they probably need to do something quite radical — maybe retreat from the area."
Research supervisor Associate Prof Michael Hilton said the trial had national significance.The John Wilson Ocean Dr dunes were an ‘‘extreme example’’ because the space between the road and the front of the dunes was so narrow.
"If we can achieve such sand build-up here, it will work in other areas."
The John Wilson Ocean Dr dunes were last wiped out in 1978. However, a decrease in foot traffic over the dunes, caused by the myth it was bad to walk on them, put them at greater risk of erosion, Mr Simons-Smith said.
Foot traffic promoted sand to be moved, and the notches had become popular walkways, which in turn assisted with flattening the dunes and moving them further from the sea.
"Some people think the coast is deprived of sand, but it’s not.
"The notches offer a more helpful utilisation of the sand which is already there so truckloads of sand don’t have to be bought in."
In contrast to other erosion control methods, the notches were designed to encourage large southerly storms to push more sand through. The coast was prone to such conditions.The Dunedin City Council supported the trial and Mr Simons-Smith had been employed to work for it on other coastal projects.
"My hope is that councils see what I am doing and let me do this notching down the whole coast."
Dunedin City Council recreation planning and facilities manager Jendi Paterson said the council was "very supportive" of the study, and it would be considered in plans to battle erosion.
She said she could not comment on the strategic direction of erosion prevention.
Mr Simons-Smith plans to give a public lecture on the trial once he has completed his thesis.
