Central Coast Council staff have recommended removing The Entrance Beach Groyne, listing a number of reasons why it should go.
These include: increased erosion of the southern shoreline north of the structure; increased risk to Council’s seawall built to stabilise Marine Pde; and changes in flow that have significantly impacted Council’s ability to successfully manage the entrance for flood mitigations purposes.
“It is the view of Council staff that the impacts are, on balance, adverse and that the trial be concluded, with the groyne removed to reinstate natural processes,” a report to the Catchments to Coast Advisory Committee said.
The staff recommendation was discussed at the final meeting of the committee, one of many committees that are finishing up because their terms end before the council elections in September.
The June meeting adopted the recommendation that the committee “notes with concern the range of the negative impacts of the Groyne at The Entrance Channel and believes that the time for monitoring of the Groyne has passed and recommends that Council approach the NSW Government to find a solution”.
The committee’s recommendation will go to a future meeting, possibly the July meeting, of Council for any further action but the report noted that Council has already written to the NSW Minister for Transport and Minister for the Environment expressing the views of Council staff.
In 2017 the NSW Government constructed the rock groyne on the Entrance Beach to the south of the entrance to Tuggerah Lakes, against the advice from Central Coast Council and the (previous) NSW Coastal Panel at the time, the report to the committee said.
“The NSW Coastal Panel recommended that the groyne be viewed as ‘in the context of a short-term (say 10 year) trial with appropriate monitoring in order to highlight and re-dress any unintended adverse outcomes that might arise from the placement of a groyne structure in this location’,” the report said.
Since the construction of the groyne in 2017, Council staff said in the report that they have observed adverse impacts progressively over time correlating with depletion of the average pre-groyne profile and conditions.
These changes significantly impacted Council’s ability to successfully manage the entrance for flood mitigations purposes.
“Since Tuggerah Lakes flooding in February 2020 and subsequent flooding there has been an increased need for entrance management operations to help train the entrance further to the north away from the rock shelf and groyne so that it can then scour into a wide and deep channel,” the report said.
“Previously the need to have to intervene was very rare, normally only associated with managing a complete entrance closure.”
Council said it was now more difficult and required significantly more effort to redirect flow to berm areas where it can scour effectively.
“It’s suspected this constrained position may increase flood risk, peak flood levels and durations of elevated water levels where it cannot be successfully adjusted,” the report said.
“The uncertainty relating to the full extent and significance of longer-term adverse impacts and what actions the NSW Government will take for rectification is now impacting the delivery of State-supported grant projects; the Tuggerah Lakes Flood Study Review and the Tuggerah Lakes Coastal Management Program.
“These are intended to set the long-term strategy for the coordinated management of the coast and floodplain and their reliability is critical for all involved stakeholders.”
It was the view of Council staff that the impacts were, on balance, adverse and that the trial should be concluded, with the groyne removed to reinstate natural processes.
Merilyn Vale
If the person whom deligated the seawall knowing it may fail…then this person should be named…and would this person be a council affiliated person…and is this person going to be held accountable for the flooding events from the breakwall being constructed… and is this person back stepping like all the current senior managers at Central Coast Council, because now they’re soon to be on award pay rates, with performance accessments every 3 months just like the employee…no longer the day out to the races…
can the rocks be moved to the north side of the entrance channel to stop it from closing?
it’s good to see authorities pro active.
Breakwall
Groyne
how about council focusing on rectifying previous mismanagement that has resulted in rate payers paying higher and higher rates?
The state government and council has access to reports as well as the capacity to undertake thorough hydrologi al surveys to not only understand the tidal flows and impacts of heavy rain events, but also that they have access to repeat historical events that caused flooding and erosion events. Importantly, this information enables modelling for a seawall to maintain a lake entrance of 100 metres. if you look at every single ocean outlet, as I have, the openings either have a natural formation maintaining the channel opening or the implementation of a man made structure such as a breakwall, to address the issues of sand erosion and flooding. Tuggerah lakes is the ONLY lake system in NSW with no natural barrier nor man made breakwall to mitigate the issues affecting the lakes system.
As a ratepayer I am offended by the compounding effect of inaction and denial by government to undertake proper investigation of a long term solution. The Tuggerah lakes system continues to silt and reduce overall water capacities exacerbating flooding to homes. When I purchased my property the zoning was 1/100 year flood zone. We’ve been flooded in several times over 35 years. The issue therefore is man-made and will require a man made solution. Do the homework and impleme t a tried and tested solution.
the north entrance beach has also been adversely impacted since the introduction of the groyne and this should also be included in any remedial action.
All you need to do is move the rocks from the groyne or breakwall and place the rocks over from the edge of the channel on the southern side and connect it all together so it is all as one point to the next. In other words put the rocks from the ocean rock side of the channel across to the rocks that is already there at the dog leg where the green weed is so there is no sand in the middle bit just like a normal wall and then it will erode itself in.
All you need to do is move the rocks from the groyne or breakwall and place the rocks over from the edge of the channel on the southern side and connect it all together so it is all as one point to the next. In other words put the rocks from the ocean rock side of the channel across to the rocks that is already there at the dog leg where the green weed is so there is no sand in the middle bit just like a normal wall and then it will erode itself in.
thankyou