Where are the rock groynes on the Gold Coast?
Where are the rock groynes on the Gold Coast?
Kirra Groyne Two groynes were constructed at Kirra Point and Miles Street to reduce coastal erosion along the southern beaches in 1972.
What is a groyne in beach terms?
A groyne is a shore protection structure built perpendicular to the shoreline of the coast (or river), over the beach and into the shoreface (the area between the nearshore region and the inner continental shelf), to reduce longshore drift and trap sediments.
What causes erosion on Gold Coast beaches?
High winds, powerful king tides and severe weather events – storms and cyclones – have all contributed to the erosion of beaches in the past and will continue to do so in the future. Erosion at Palm Beach following a cyclone that hit the Gold Coast in 1954.
How is Burleigh Heads impacted by erosion?
The sand is unstable and could collapse on top of anyone underneath. Scarping of up to 2 metres has occurred at Narrowneck, further down the coast a metre of sand has been eroded away at Burleigh Heads by the gale force winds and swells of up to 6 metres across the weekend.
What are the disadvantages of groynes?
Disadvantages
- Short lifespan.
- Reduces recreational value of beach.
- Reduction of longshore drift can lead to higher erosion rates downdrift (terminal groyne syndrome)
- Ongoing maintenance cost.
- Using tropical woods will mean it’s unsustainable.
Are Gold Coast beaches at risk?
Gold Coast suburb has $1.4bn in property at ‘very high risk’ from coastal erosion. New data has identified the affluent Gold Coast suburb of Paradise Point as having the highest value of property at risk of coastal erosion in Australia.
What problems do groins cause?
The problem with groins is that they trap sand that is flowing to a neighboring beach. Thus, if a groin is growing the topographic beach updrift, it must be causing downdrift beach loss.
How tall is a groyne?
The same groyne can act either as emerged or submerged structure (Figure 2a), depending on water level changes due to tides and storm surges. Generally, groynes are designed to stick out about hs=0.5-1.0 m above mean sea level (MSL).
What are the environmental processes that have eroded Gold Coast beaches?
This study, known as the Delft Report, recognised that the movement of sand within the nearshore zone of the Gold Coast is influenced by two major coastal processes: longshore drift and alternate erosion and accretion (see Longshore drift Information sheet).
What is the best coastal Defence?
Sea Walls. These are the most obvious defensive methods. Sea walls are exactly that. Giant walls that span entire coastlines and attempt to reduce erosion and prevent flooding in the process.
Why do beaches have groynes?
Groynes are man made barriers from the back of the beach and down to the sea. Bournemouth groynes are created to prevent the sand on the beaches being washed away with longshore drift. The groynes run perpendicular to the shore extending from the beach promenade into the ocean.
What effect do groins have on beaches?
Groins are shore perpendicular structures, used to maintain updrift beaches or to restrict longshore sediment transport. By design, these structures are meant to capture sand transported by the longshore current; this depletes the sand supply to the beach area immediately down-drift of the structure.