Showing posts with label inundation. Show all posts
Showing posts with label inundation. Show all posts

Tuesday 8 August 2023

Tweed Shire Mayor Chris Cherry: "I think that [the 2022 flooding] has been a big wake up call for all of us."

 

IMAGE: Google Earth snapshot showing 40 Creek Street, Hastings Point & environs. Retrieved 7 August 2023. Click on image to enlarge.








In the matter of Development Application DA20/0386 for a 13 lot subdivision (11 residential lots, 1 drainage lot and 1 residual dedicated riparian lot) at Lot 156 DP 628026 No. 40 Creek Street, Hastings Point made on behalf of Queensland-based Palm Lakes Works Pty Ltd on est. 17.77 ha of flood prone, environmentally sensitive, estuary land which includes preferred koala habitat and SEPP14 wetland.


The Tweed Shire Council meeting which refused development consent saw councillors cast their votes 6 to 1. The sole councillor in support of the DA, was former National Party campaign director and former mayor Cr. Warren Polglase, who in speaking to the motion was moved to utter words to the effect that he did not believe that climate change was occurring here not having seen it with his own eyes. 


Echo, 7 August 2023:


Click on image to enlarge







The Tweed Shire Council has refused a development application (DA) for an 11-lot subdivision at the site of 40 Creek Street, Hastings Point.


The site is zoned residential but ‘has significant environmental constraints as well as being flood prone’ according to the staff report. Despite that, Council staff recommended approval of the DA.


Mayor Chris Cherry told the Council meeting (3 August) that in 2019 she had been one of the councillors to propose ‘in-principle support’ of the subdivision.


Looking through that and looking at what that support was based on, it was conditional support based on this application not increasing its development footprint. It was based on it complying with a number of different conditions that were very important to the council of the day and the community.’


Councillor Cherry said point six of the in-principle support stated that:


Any future development application that proposes to increase the number of lots, reduce the size of lots or vary any other developments controls to intensify yield or the development footprint or further impact on the buffer or environmental areas will not be looked on favourably by Council.’


Cherry went on to detail a number of ways that the current DA went beyond the basis of the in-principle support, saying that in ‘the proposal in 2019 only three of the lots were intercepting into the 75m ecological buffer zone. Now most of them are, I think seven of them now [are] into that 75m buffer zone. So the developable footprint has increased.


The lot for the existing house was 800 square metres in the plan in 2019. It is now 1,470 metres square.


2022 flood


There are a lot of changes that have been made that increased the impact of this development. But the biggest thing that has happened in the time since the in-principle support was given is the 2022 floods. I think that has been such a big wake up call for all of us. And we’ve heard today from the flooding experts, from Floodplain Management Australia and the planning expert who came forward, just how much consideration we should be giving to the location, to the impact of storm surge in a climate change future that we are most definitely going to see. And I think it is imperative that we take this very seriously. [my yellow highlighting]


Most of you would have seen the article in the Sydney Morning Herald [saying] that it is inexplicable that Hawkesbury Council keeps approving developments of a floodplain when they have gone through such a massive flood. It is the same for us. We can’t keep repeating the same mistakes. We can’t keep saying it will be okay. To put 2.2m of fill across this site to get flood immunity for the new residents is simply not the way. That’s not good planning. That’s not the way we need to go forward as a community…..


Full article here.


Friday 16 September 2022

If the NSW Government and emergency services tell Yamba it rarely floods and its houses are safe from all but extreme flooding, are the town's residents supposed to believe them?

 

Below is a fairly typical description of Yamba and environs during high rainfall and flooding events.


Even though it appears text and images have been produced between 2015-2021 it seems to be considered by the NSW Government as a contemporary description rather than an historical one.


Read it carefully if you live in Yamba or have been a holidaymaker in the town when the Lower Clarence River has been in flood in recent years.


NSW State Emergency Services (SES), Flood Awareness NSW, retrieved 13 September 2022:


CLARENCE RIVER

Clarence Valley LGA


Yamba and Palmers Island – Are you at risk?

Yes you are!


Yamba is located on the southern bank of the mouth of the Clarence River. The main impact of floods in the area is isolation, however several residents and commercial properties can be inundated in severe floods. Even in minor floods, Yamba may become isolated when Yamba Road closes. Another consideration during local floods is the influx of tourists during holidays and summer season, who may be unaware of the local effects of flooding.


Palmers Islands is located directly west of Yamba on the southern bank of the Clarence River. Most of the land on the island is prone to flooding. In a minor flood, Palmers Island becomes isolated and surrounded by flood water. In a major flood some properties may experience over-floor flooding and some residents may need to evacuate.


Rural land along the Clarence River around Wooloweyah Lagoon can also be inundated and substantial numbers of rural properties can become isolated.


The period of isolation for these areas can vary depending on the size and duration of the flood, as well as high tides preventing drainage to the sea. Any residents wanting to leave the area would need to do so before flooding causes Yamba Road to close.


Palmers Island Yamba Road Store and School Flooding 


Do those five short paragraphs and that one image match your experience of floodwater and stormwater inundation in Yamba over the last 30 years?


Is it still mostly the inconvenience of isolation that the Yamba community suffers? Is it an accurate description to say that only “several residents and commercial properties can be inundated in severe floods”?


Is anyone else in Yamba asking themselves why that first paragraph quoted here is still accepted uncritically by state authorities, when the lived experience is that the inundation situation has been gradually becoming more pronounced over decades. That the amount of water entering town commercial and residential precincts is long past just nuisance value.


The natural flood storage areas and flood ways within the town, which carry water overland to the river estuary and out to sea, no longer function. In large measure due to the degree of draining, infilling and building over of these these features which has occurred over time and the fact that: (i) the town’s stormwater system can no longer adequately cope with the amount of rain falling from the sky and subsequent rainwater runoff from sloping ground/hard surfaces; and (ii) the river water arriving as flood carried down from higher up the river system whose swirl through town streets is often exacerbated by a tidal pull.


There are residents whose homes have been inundated at floor level in both 2021 and 2022 and residential lots which experienced stormwater/floodwater intrusion onto the property for the first time or at a deeper level that previous flood periods according to homeowners.


A better description of the changing Yamba experience of flooding can be found in an Inside Local Government article of 26 May 2022:


Clarence Valley Mayor, Ian Tiley, has demanded the Clarence be included in any 2022 flood studies and assessments, saying the region had been ignored in initial assessments by the NSW Department of Planning and Environment.


Mayor Tiley put forward a Minute at the June Council meeting following advice from the Department of Planning and Environment that post flood data behaviour assessments already undertaken had focused on the Richmond, Wilson, Brunswick and Tweed rivers – local government areas to the north of the Clarence Valley.


The flood level at Grafton was not a predictor for the flood behaviour downstream,” the Mayor said.


It is clear the Clarence flood increased in volume as it moved downstream and staff consider it likely the extreme localised rainfall events in the tributaries of the lower catchment impacted Clarence River levels downstream of Grafton, and that post flood data behaviour assessments may inform these assumptions.”


CVC previously reported in April that Yamba experienced its biggest rainfall event on record, with 1267mm in February and March. This included 274.4mm on 28 February – the highest 24-hour February total on record – and 258.2mm on 1 March for a total of 532mm.


There has been no event or combination of events since records began that comes close to the rainfall totals recorded at Yamba in February and March,” Clarence Valley Council Director Works and Civil, Jamie Fleeting said at the time.


Getty Images has a collection of photographs which clearly demonstrate the growing dissonance between what is written by government agencies about flood behaviour and the lived experience of the Yamba community in March 2022.


YAMBA, AUSTRALIA - MARCH 02: An aerial view of a flooded street and properties in the town of Yamba, in northern New South Wales, on March 1-2, 2022 in Yamba, Australia.

(Photo by Elise Hassey/Getty Images)


Note: Hover mouse over upper righthand corner of images to reveal "Share" and "Full Screen" buttons.


Embed from Getty Images Embed from Getty ImagesEmbed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images Embed from Getty Images


BACKGROUND


Australian Bureau of Meteorology, Special Climate Statement 76 – Extreme rainfall and flooding in south-eastern Queensland and eastern New South Wales, 25 May 2022, excerpt:


Summary


Extreme multi-day rainfall and significant flooding affected south-eastern Queensland and eastern New South Wales from 22 February to 9 March 2022. The heavy rainfall began in south-east Queensland and north-east New South Wales during the last week of February, and continued further south into eastern New South Wales in March (Figure 1).


Multi-day rainfall records were broken across south-eastern Queensland and north-east New South Wales, with multiple sites recording over 1 metre of rainfall (Figure 2). For the last week of February, rainfalls across parts of the region were at least 2.5 times the February average (based on the 1961–1990 period), with some parts more than 5 times the average. For north-east New South Wales and large areas of south-eastern Queensland, this was the wettest week since at least 1900. The intense and sustained rainfall across the region led to flash flooding and riverine flooding extending from Maryborough in Queensland to Grafton in New South Wales. Some areas of south-eastern Queensland, such as the Mary River at Gympie, recorded their highest flood peaks since 1893.


Widespread major riverine flooding also occurred in the Sunshine Coast region, and in the Brisbane, Logan and Albert River catchments. In parts of north-east New South Wales, peak flood levels broke previous observed records (reliable since at least 1974 and for some locations dating back more than 100 years) by considerable margins. Devastating flooding occurred through Lismore (Wilsons River) and other nearby towns, including Coraki and Woodburn (Richmond River) and Murwillumbah and Tumbulgum (Tweed River).


In the first week of March, the rainfall system shifted south along the New South Wales coast, bringing further heavy rainfall to eastern parts of the state (Figure 3). As a result, the Hawkesbury-Nepean catchment recorded its wettest 9-day period on record (since 1900) to 9 March (Table 11). With rain falling on already saturated soils and swollen rivers, flood levels in the Hawkesbury-Nepean river system exceeded those reached in March 2021 and were comparable to those of 1978 (Table 12).

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Sunday 30 January 2022

Time for that annual warning about the folly of over-developing Australia's coastline due to increased flooding, erosion and sea inundation. A warning that all three tiers of government have blithely ignored for too many years

 

Science and climate modelling has been informing people living in Australia's coastal zones that global warming-induced sea level rises, along with changes in east & west coast current speeds, more erosive wave patterns & increased flooding, will make living along the coastal fringe highly problematic the deeper the earth moves into this era-long climate change.


Coastal residents have been warned every year since at least 2006 and 2022 is no different.


This is the message in 2021-22.


What the NSW Government’s ADAPT NSW has to say about climate change-induced sea-level rise along the state’s coastline:


Projected sea level rise along the NSW coast

There is a direct relationship between climate change and sea level rise. As our climate warms, sea level rises mainly because of thermal expansion (when water warms up, it expands) and melting of snow, glaciers and ice caps (which increases the volume of ocean water). However, sea level rise is also effected by local oceanographic processes (e.g. changes to ocean currents) and changes to land levels.


Sea level rise is projected to accelerate over the 21st century. The most recent sea level rise projections are from the Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report. The IPCC predict a likely sea level increase on the central NSW coast of


between 0.21m and 1.06m by 2100, and

between 0.28m and 1.95m by 2150.

This is dependent on the level of future greenhouse gas emissions.


IPCC modelling suggests slightly higher sea level rise to the north of the state and slightly lower to the south. These projections do not include processes associated with the melting of ice sheets which for NSW could result in sea level rise of up to 2.3m by 2100 and 5.5m by 2150.


In the longer term, the IPCC show sea level is committed to rise for centuries to millennia due to continuing deep ocean warming and ice sheet melt, and will remain elevated for thousands of years.


If warming is limited to 1.5°C, global mean sea level will rise by about 2 to 3m.

for 2°C, 2 to 6m is expected, and

for 5° 19 to 22m is expected.  


This is the current seawater inundation scenario message in Predicted Coastal Flooding Resulting from Climate Change, based the IPCC Sixth Assessment Report Update 2021.


Examples from Coastal Risk Australia 2100 interactive mapping tool using IPCC scenarios for the period 2021 to 2100.


Sometime in the next 79 years this is what two small coastal towns will probably look like from the air.......


Ballina, New South Wales - blue area seawater inundation at 0.8m





Yamba, New South Wales - blue area seawater inundation at 0.8m


The Daily Telegraph on 18 January 2022:


The Coastal Risk Map shows what Australia will look like if sea levels rise due to climate change, showing how much extra water will filter into our cities and suburbs and the impact it will have on our way of life.


The map was originally created by spatial mapping company NGIS with non-profit partner Frontier SI in 2015, but has recently been updated with new data from the United Nations Intergovernmental Panel on Climate Change’s Sixth Assessment Report.


The sea level projections show that if greenhouse gas emissions are moderated, the ocean may rise by 0.84m by 2100.


But a global rise approaching 2m by 2100 and 5m by 2150 would be possible under a very high greenhouse gas emissions scenario- much higher than first thought.


NGIS Executive Director Nathan Eaton said the aim of the map was to illustrate the data and give Australians a better understanding of how sea level rises could impact their lives.


Previously the map showed a rise of 0.74m at it’s lowest, that’s since changed to 0.84m,” Mr Eaton said.


Now less than a metre doesn’t seem like a massive difference to someone, but in low lying areas, even 10 centimetres can make a huge difference.”


Geobiology, archaeology and sea level expert Dr Ben Shaw said the map could be a “wake up call” for authorities on the urgency of curbing climate change.


It’s phenomenal to see how impacted parts of Australia will be … a real concern for people living in Sydney, across NSW and around Australia, our coastline will look very different and there could be a serious environmental disaster,” Dr Shaw said.


We will see the impacts of climate change regardless, but if we put the policies and strategies in place now to curb it … it can make a huge difference over generations and decades to avoid something like this.”


Otherwise things like our water sources, our infrastructure, our suburbs and way of life may have to change drastically.”


The Daily Telegraph has analysed the Coastal Risk Map to see just how much a five metre rise in sea levels would impact NSW - here’s what we found and how it will affect you.


HOW NSW WILL CHANGE IF SEA LEVELS RISE


Under the current worst case projections, if sea levels rise by 5 metres by 2150:


FAR NORTH COAST (Tweed Heads and beyond down to Coffs Harbour)

Most of Coffs Harbour will feel the impact of rising sea levels. Residents living in the vicinity of Boambee Beach out to North Boambee Valley and in and around Park Beach will be impacted, with water set to flow into the CBD.


Moonee Beach and significant sections of Woolgoolga and Emerald Beach will disappear or become a small set of islands as water flows above the shoreline. Other beachside areas like Red Rock, Wooli and Sandon will be overrun and become lakes or bays.


A major new lake system will be established flowing more than 60km inland from Yamba to Grafton if sea levels rise.


Areas like Grafton itself, Cowper, Townsend Harwood Island, Talumbi and Yamba and Wood Head will cease to exist, forming a large lake with a the village of South Arm in the centre.


A similar large harbour will be carved out between Evans Head and Lennox Head, swallowing up Ballina, Wardell, Broadwater, Coraki, Woodburn and as far down as Bungawalbin, with waterways also swelling to impact Lismore.


Directly along the coastline, the enclave of Byron Bay will be completely awash, as will every other settlement stretching up to Kingscliff and past the Queensland border.


Water will overtake Brunswick Heads, New Brighton, Pottsville, Hastings Point, Casuarina all the way up to Tweed Heads, flowing inland to inundate areas like Murwillumbah, and creating another large lake.


Down near Byron, Mullumbimby will also be severely impacted.


Monday 29 July 2019

247,000 coastal homes in Australia are in the firing line if sea level rises reach 1.1metres


ABC News, 22 July 2019:

The latest figures from the Department of Environment  warn a sea level rise of 1.1 metres, considered a high-end scenario, would cost $226 billion nationally by the end of the century.

If that eventuates, it would put up to 68,000 homes at risk in Queensland and the same number in New South Wales.

In Victoria and South Australia, it would be up to 48,000 homes, up to 30,000 in Western Australia and up to 15,000 in Tasmania.

Every coastal community in Australia is doing its own mapping, but Noosa may take it a step further.

The Noosa Shire is now considering how best to warn owners, both current and future, about the risk.

Councillors say the estimated 2,232 Noosa properties likely to be affected by storm flooding in 80 years' time could be told directly via rates notices.

Possible buyers may also be alerted through routine property or rates searches.

Noosa Mayor Tony Wellington said it was "a problem that every coastal council is facing around the world now — and it's an issue of defend or retreat obviously".

"What we have to look at is whether it is feasible and possible to defend property, in a worst-case scenario, or whether it is not possible, and what the cost implications are," he said.

"And then you have to ask whether all residents should be funding for protection of a few properties.

"It's a very complicated issue."

The Mayor also said it was a matter of "buyer beware" and those in low-lying areas ought to know the risks.

In 2015, a report to Byron Bay Council warned that certain homes may become "voluntary house purchases" where the council buys homes at risk of flooding "to reduce risk to life and limb"…..

The Insurance Council of Australia said climate declarations and long-term fears of flooding would not affect premiums, but actual storm or water damage could.
"If you're already at risk and climate change predicts that you will become further exposed, then your premiums over the next 30–80 years will go up to reflect changes in that risk," the council's Campbell Fuller said.

Even the current rate of global sea level rise at 3.4mm each year has the potential to impact on vulnerable coastal towns such as Yamba on the NSW Far North Coast.

Excerpt from Clarence Valley Council Yamba Floodplain Risk Management Plan, February 2009:

Flooding at Yamba can occur as a result of a combination of high flows in the Clarence River, high ocean levels, wind wave action along the foreshore or from intense rain over the local catchment. The risk to life due to river flooding is considered to be low as inundation occurs gradually and with several hours (or days) warning. Similarly, flood hazard resulting from ocean storm surge is also considered low as there is likely to be several hours warning of an event, with the peak of the storm lasting for less than a day. The Floodplain Risk Management Study indicates a storm surge warning time of 6 to 24 hours. It should be noted however that the flood hazard can become high if the low lying community to the west of the town does not respond to flood warnings as the available high ground is only accessible by Yamba Road, which is readily cut by floodwaters. The only road out of Yamba to the Pacific Highway is also inundated in the 10y ARI and greater flood events. [my yellow highlighting]

Ballina is another  coastal town on the Far North Coast. Its CBD is on the banks of the tidal Richmond River where it empties into the sea.

Sea level rise is something Ballina has been discussing for many years because for the Ballina community the evidence is right before residents’ eyes.

This was Tamar Street in the CBD in January 2018 showing saltwater intrusion at high tide.

Photograph supplied by @Captainturtle


Other Far North Coast towns and villages are also under threat of foreshore/beach erosion, wave overtopping and/or innundation, including Wooli, Belongil Beach and Clarkes Beach.

Wednesday 9 July 2014

When the ocean begins to flood a city.....


An object lesson for the Abbott Government and many communities on the east coast of Australia....

Quartz 30 June 2014:


The usual US partisan divisions over climate change were absent today in the state of Virginia, where Republican and Democratic officials met to discuss what to do about the threat of rising sea levels to the state. The proposals include the launch of a climate-change task force, which Virginia's Democratic governor will announce tomorrow. Christina DeConcini, government affairs director at the World Resources Institute, a research organization, told Quartz this is the first time to her knowledge that Republican leaders (very few of whom accept global warming is both real and man-made) and Democratic ones have come together to craft a policy on global warming.
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That's probably because Virginia is more vulnerable to storm-surge destruction than anywhere else on the US's east coast. Problems are particularly acute in Norfolk, Virginia's second-biggest city and home to the world's largest naval base; sea levels there are now 14.5 inches (37 cm) higher than they were in 1930—so high that parts of Norfolk flood when the moon is full. Sea levels are rising faster there than anywhere else along the coast, due to the vagaries of ocean currents:
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Sewells Point is a peninsula off Norfolk.Natural Resources Defense Council

"A severe Category 2 or a Category 3 storm—if we were to receive a direct hit, almost all of the city would be underwater," Paul Fraim, Norfolk's mayor, told National Public Radio in 2012.
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This doesn't mean that high tide is lapping at Virginians' front doors. The main danger comes when storms pummel the coasts with huge waves, which are amplified by tidal forces. Here's an illustration of how high tides and storm surges, as they're called, differ:
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"Virginia Hurricane Evacuation Guide"

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