|The old seawall is very steep and many of the rocks are not supported from below|
|Graphic of seawall design from public notice sign -showing the lower angle and extended toe.|
|Gap bashed though seawall by Cyclone Yasi - Tully Heads|
|Rocks thrown up from seawall onto lawns|
|Machans Beach Esplanade is very narrow, so another way had to be found to access the seawall|
|Tipping out rocks|
|A larger rock barely fits in the bucket|
|Reversing along the wall to the excavator|
|Mirrors are handy for this job|
By November 2014 the seawall stretched more than half way along the Esplanade and the causeway was in excess of 1 km long. Trucks would drive forwards along the causeway and turn on little ramps that ran from the causeway to the Esplanade. These ramps are also where the excavator is parked when the tide is high. The trucks then reverse the final hundred metres or so the the waiting excavator.
|The causeway is now so long, that the excavator has to wait for loads of stone to arrive|
|Before placing rock, mud is dredged from the tip of the causeway and placed on the side|
|A bucket full of mud - the mud was plastic so not much turbidity resulted|
|Dumping large rock with the excavator poised to catch the truck should it start to roll over|
|View along the top of the partially finished new seawall, showing soil being laid where the footpath will be|
The seawall is made up in layers, which small stone (~150 mm) being formed into bank, which is then covered with a layer of geotextile. Geotextile will add strength to the seawall as it has a very high tensile strength but its main purpose may be to stop fine material being eroded out of earth behind the wall by the movement of tides and waves. Loss of fine material can create deep holes in the ground. On top of the white geotextile is a layer of smaller rock, each of the smaller stones would be the size of the bucket on a builders wheelbarrow, which is roughly the size of the stone in parts of the original seawall. On top of the smaller stone, truly large stones are being places with may having a long dimension of close to 3 metres.
|Layered construction of seawall|
The project will continue well into 2015 and I will keep you posted.