RESIDENTS last week supplied their own flood observations to the consultants developing the Narooma flood study, while getting an explanation of what the planning document is trying to accomplish.
Subscribe now for unlimited access.
$0/
(min cost $0)
or signup to continue reading
Around 20 people attended the first drop-in session last Wednesday evening, while slightly fewer attended the daytime session the next day.
Consultants Erika Taylor and Erin Askew from WMA Water said attendees were primarily from low-lying areas and most wanted to know how the plan would impact on their own property.
The comprehensive study covers the coastal inlets of Mummaga Lake, Kianga, The Duck Pond and Wagonga Inlet and represents progress towards replacing council’s interim coastal hazard adaptation code.
It is meant to provide certainty for developers and property owners around what can be built in these locations, including the commercially important Narooma Flat.
The study also applies the sea level rise projections adopted by Council last November, which are lower than the previous NSW Government policy.
Once adopted, residents will also no longer be required to undertake a flood study to build, and according to council, residents can be provided with clearer advice and longer term certainty in respect to the flood risk for the Narooma area.
Council’s coastal and flood management planner Norm Lenehan said the primary focus was the behaviour of flooding waters and consultants wanted to hear from as many residents as possible, especially those with measurements and photos from past flood events.
“We’re interested in seeing observations from people who live here and comparing their experiences with the modelling to see if there is good correlation,” he said.
Submissions could be made via the council website, while there was also a submission box at the Narooma library until July 31.
Ian Hitchcock, a local spokesperson for Dalmeny lakefront property owners, believes the computer modelling carried out by the consultants was seriously flawed.
Peak lake levels modelled for the major 2010 flood event were a metre and more above the actual lake levels recorded by local residents, he said.
“As proof of the modelling failures, residents identified houses, built at levels well below the modelled flood levels, which have in fact, never been flooded,” he said.
“Residents are concerned that if the study is adopted by Council in its present form, flood planning levels in the order of 4 metres AHD would be applied to all new development in Dalmeny.
“More existing properties will carry the ‘flood affected’ label, and the value of these properties will take another nose dive. Insurability will also become an issue for the owners.”
Mr Hitchcock’s views can also read on the Letters Page of today’s News.
Councillor Milton Leslight attended the Wednesday session with the Dalmeny residents and shared their concerned about how the flood study was being put together.
Clr Leslight said he was however was optimistic that the consultants and council staff would take the resident’s concerns on board and rectify the modelling errors.
While the flood study primarily looked at run-off from rainfall events and catchment conditions, sea-level rise and inundation from the ocean was also part of the picture.
Clr Leslight was also concerned about how the study relates to sea-level rise and how that would impact on property owners.
He said incorrect benchmarks could result in restrictions such as homeowners and builders having to renovate or build costly elevated structures.
“A new policy for floodplain management is based on flawed sea level policy, so the flow-on effects for property owners will be pretty devastating unless the benchmarks are accurate,” he said.
Another issue raised at the drop-in sessions by both Mr Hitchcock and fellow Dalmeny resident Peter Bernard was the procedure used by National Parks to open Mummuga Lake in times of flooding.
They both said they would like to see the lake opened sooner when flood waters threatened adjacent properties.
A representative from the Department of Environment and Heritage was also present at the drop-in sessions.
The draft Narooma coastal inlets flood study remains on public exhibition until Friday, July 31 and council welcomes feedback from property owners and the broader community over this period.
If people have questions, they can contact Norm Lenehan on 4474 1000.
The 1 per cent flood explained
THE illustration on the front page of the Narooma News is indeed alarming but the map shows a 1 per cent flood and this is the event council has been directed to reference by the NSW Government for residential planning controls.
Mr Lenehan said this meant there was a 1 per cent chance of the flood occurring, replacing the old terminology of 1 in 100 which was misleading in that people believed such events could only occur once in a 100 years.
Council adds 500mm freeboard for residential properties as a safety measure to account for wave action from wind, wake from cars or boats passing through, and other uncertainties.
The 500mm also increases the likelihood of floors being above the flood level to reduce the likelihood of damages
The flood depths used are based on the Flat having depths below 1m and in most cases, below 0.5m.
You can see the 2m flood depth contour is inside the inlet. You can also see some areas of the Flat are flood free during this event.
It is important to note that “flood depths” is different to flood levels.
Flood depth is how deep the water is, while flood level is the height above Australian Height Datum.
For example, you may have a flood level of say 4mAHD, but the depth may only be 0.5m if the ground level is 3.5mAHD.
The figures in the map are flood depths.
