Built at the right angles to shore, they will prevent longshore drift and absorb the energy of the sea. They will trap sand inbetween the groynes over a period of time and the beaches will be automatically be replenished. Scale models at the University of Stellenbosch will determine the position and lengths of the rock groynes as well as any side effects they may cause.
In order to protect the retaining walls and other valuable real estate sand built up is a necessity and not only nice to have for beach goers.
Examples of what these groynes can achieve are to be found all along the North Sea beaches in France, Belgium and the Netherlands. At low tide the beach extends for miles.
An example closer to home is Durban central beach. Before the new pier was constructed in the 80’s there was no sand at all along this section of the promenade, although some sand is also to be replenished by a pumping scheme.
Rock groynes will have the added benefit of attracting marine life in all forms and sizes. A tidal pool will never achieve this objective.
No need to waste money on a tidal pool. This money should rather be spent on extending the walking/ cycling path from Durban Blue Lagoon to uMhlanga.
H Carlier
La Lucia
