The wind nets have been installed at Fish Hoek Beach as part of the City’s dune project.
The dune project at Fish Hoek will stop nearby roads, railway tracks and buildings being swamped by sand and should be completed by July next year, says the City.
Mayoral committee member for spatial planning and environment Eddie Andrews, who visited Fish Hoek Beach last Thursday to check on the project, said he was pleased with its progress despite unusual south-easterly winds last month.
The City says the project aims to trap windblown sand to protect infrastructure near the beach, but some Fish Hoek residents and beachgoers say the dunes shielded the town from windblown sand and flattening them - as has happened with the project - could see more sand dumped on the town, not less.
Asked about these concerns, Mr Andrews said the dunes acted as a shield against windblown sand, storm surges and rising sea levels, but if they weren’t managed, sand could swamp the main road, the railway line and other infrastructure. So it was necessary to “reduce the volume” of dunes near infrastructure.
“None of the dunes, Fish Hoek or Glencairn, are typical fore-dunes in that they are very narrow and steep, instead of having a broader base and lower or flatter profile,” he said.
“The management objective of the project at Glencairn and Fish Hoek is to reprofile the dunes by reducing the volume of sand and creating a profile more typical of fore-dunes and revegetating these areas with a diversity of coastally adapted plant species to improve their ecological function, similar to what has been successfully demonstrated at Hout Bay.”
The end result would keep the dunes and windblown sand in check while protecting infrastructure near the beach, he said.
“Maintenance will be reduced in the long-term once vegetation is established and the dunes are maintained,” he said.
“Once these projects are completed, residents can expect a decrease in sand accumulation on buildings, roads, and railway tracks in the area.”
Asked about the dune project, UCT professor George Branch, who is the co-author of Living Shores and the Two Oceans Field Guide, said dunes should not be stabilised or destabilised from their natural state without a valid reason.
"That disrupts the flow of sand that naturally occurs between the dunes, beaches, and marine sands and decreases (or increases) the natural shifts of sands,” he said.
However, he acknowledged that protecting the railway tracks could be considered a valid reason for intervention.
Environmental activist Kim Kruyshaar said that based on historical photographs and previous attempts at stabilisation, the dunes were too near the sea.
"Typically, there are small hummock dunes that erode during high seas, but the dunes immediately behind them remain stable. However, in Fish Hoek, there isn't enough space for these smaller dunes to catch sand, which is then carried out to sea. As a result, the waves break further out, reducing the energy that reaches the beach and protecting the permanent dunes."
The proximity of development to the coast made it necessary for the City to artificially manage the dunes, she said.
“The frequency of this management will depend on weather and sea conditions, as well as the success of revegetation efforts.”