Why?
The erosion on this section of land (which includes Elements of Byron resort land, Crown land and land owned by Byron Shire Council) is caused by a chain of events which, while they involve natural processes, are also affected by human intervention. Having said that, it is not our intention to apportion blame as circumstances unfold with people doing the best that they can with the information they possess at any time. And a great deal more is understood today regarding coastal processes and protection than in past years.
From the public beach access north to Tyagarah (in fact from considerably south of the public beach access) there is still natural coastal habitat. However the same cannot be said, unfortunately, for the area that is the subject of this proposal and the existing coastal protection works.
The images and text below show how the entrance to the Creek is being pushed further and further north. While there is some degree of natural migration of sand northward, in this instance the sand migration is exacerbated due to hard revetment (buildings and rock walls) located at Belongil.
Another factor is the opening and closing of Belongil Creek. The creek is opened mechanically by Byron Shire Council periodically – around two or three times a year. The mechanical opening of Belongil Creek has become necessary to mitigate the risk of the Byron Town Centre flooding. Following the opening the entrance typically migrates to the north which influences shoreline erosion of Elements of Byron land.
This sand migration has exacerbated erosion due to several factors:
- The estuary ‘hugs’ and undercuts the left hand bank for a longer distance before entering the sea.
- The alongshore migratory behaviour creates a wider entrance zone, comprising a low lying sandy berm, which can be overtopped by waves during ocean storms.
- The migratory entrance channels deplete the beach sand volume available to combat the storm erosion demand.
- The remnant pools at the base of the erosion escarpment allow wave attack at a lower elevation in the dunal profile and also potentially allow some partial wave reformation before reaching the back beach erosion escarpment.
The recurved spit at the northern end of Belongil Spit and its continued vegetative stabilisation and growth in volume has forced the estuary to be diverted westward. Coupled with this behaviour has been the formation of the vegetated island; as a consequence the dominant channel now flows to the east of the island causing the estuary to take a sharp ninety degree bend at the recurved spit to flow westwards directly towards the bank.
Unfortunately, the degradation of the shoreline will continue unless we can do these soft works over 40 lineal metres to maintain the beach.