- Date published:
8:00 am, August 10th, 2019 - 75 comments
Categories: climate change, local government, sustainability - Tags: south dunedin
If we thought the devastation and mess caused by a flood ripping through the old dump at Fox Glacier village was bad, just wait until a decent storm punches through the old dump of New Zealand’s fifth largest city on its coastline. It’s getting close.
Dunedin is now preparing to have the massive Kettle Park dump exposed to the sea.
It was previously a sand dune system, and has encroached into the sea over the last century.
But it looks like the sea wants it back.
It’s not like they weren’t warned. In 2015 the whole of South Dunedin underwent massive flooding, not assisted by poorly maintained DCC stormwater drains. I am aware of people whose houses were devastated by that storm that are still gradually recovering.
South Dunedin is also on average home to some of the poorest and most deprived people in New Zealand.
It’s not the paradise first advertised.
I no longer care whether it’s called climate change or the weather. I’m sure there are differences of timescale.
As The Otago Daily Times noted in 2017, most of South Dunedin is under threat from sea level rise, and some of it is under sea water table already.
If this rubbish dump gets exposed, the next thing to go will be the entire racecourse.
After which it’s harder to stop a whole bunch of houses with people in them getting less viable.
Cities that prepare for managed retreat with big plans that help their citizens move will have a better chance than most.
Here comes the next warning.
Nows the time to build a curtain wall between the sea and the old dump while is a straightforward exercise with ground on both sides. Once you have the sea on one side it becomes more difficult and costly. Plus design it so when the sea does encroach further the wall is self supporting.
Starting now means the work can carry on over a number of years to fit the budget timeline.
Build a curtain wall?
Try thinking again; – as we remember Japan did this along the north east coast of japan remember?
Then a Tsunami came to wipe those cities out,remember?
Better to try and prepare to evacuate the residential areas away from the coasts of NZ while we have time.
Watch the Japan Earthquake & Tsunami of 2011: Facts and Information
Curtain wall will still stop the rubbish being swept away if your tsunami came knocking but unlikely .This is Dunedin coast not East coast of North Island with offshore trench like Japan.
Flooding the park isnt really a problem , no above ground structures to destroy. The pictures show a small bluff from park to beach , which is a help.
'Live on hope' – good luck with that as the whole world is in peril now no matter where you be.
As the world gets hottter those plates will expand and seas will become warmer with many tidal storms that today we have not seen yet..
Carry on = Live on hope.
from the ODT.
No action on beach erosion
Sir,- A few weeks ago you drew the attention of the public to the state of the beach between St. Clair and St. Kilda. In the meantime the authorities in charge have done nothing, but thousands of tons of sand have disappeared, and the beach is an eyesore, as it is strewn with lupins and marram grass, showing that the sandhills are fast disappearing.
There is no doubt that some parts of our suburbs will be in a very bad state if the sandhills disappear as quickly during the next six months as they have done during the last six weeks.- I am, etc., E. L. Macassey.
– ODT, 8.8.1919
"Cities that prepare for managed retreat with big plans that help their citizens move"
Ideally – but 'devil take the hindmost' is much more likely to be what happens. We've spent decades internalising a culture of seeking private gain by any legal means available irrespective of the consequences for others. It isn't going to suddenly reverse itself.
As Kapiti and Christchurch have demonstrated
That's a very old landfill. Presumably there's not hard base under it, which means the sea will be coming up from underneath as well.
The problem with the loss of protection on that beach has been known for over ten years. At the other end of the beach they started losing the seawall because of changes in wave and tide patterns. That was directly under the road that runs along the front of the esplanade shops and homes. From memory it was similar. Wave action removed the sand and once the stones are exposed they start to move and things can change rapidly.
Just found this from 2008
Given we're at the beginning stages of sea level rises, changes in coastal patterns, and frequent big weather events, I'm guessing they will have to remove the dump. I hope they make that decision quickly, which financial assistance from central government if needed.
There are also all the other dumps in Dndn near coast or waterways. I think South Dunedin has the potential to be our first big climate refugee town, but the dump issue is going to be widespread across NZ. We've been really bad at where we throw our 'waste'.
The Queenstown / Central Otago landfill at Victoria Flats could be really interesting if the mass movement areas along the Nevis fault let go and the Kawarau backed up again. But that'd probably make Queenstown very interesting too.
how much quake planning went into that landfill? I always seems odd to me to put dumps next to waterways.
The landfill was rammed through with considerable haste as the old one at Tuckers Beach was a disaster and in front of very flash properties. It did have the best views of any dump in the world though, across the Shotover River to Coronet Peak. Most of the other options were either way too small, 200 km away, or much worse
When the mass movement areas were discovered during the Clyde hydro investigations and axed any hydro development on the Kawarau, the perceived wisdom in Queenstown was that the hydro development were axed because of the protests from the Queenstown business community. The hydro scheme would have destroyed the rafting industry on the Kawarau.
Roll forward 10 years to the establishment of the new dump in early 90's and any contrary views were shut down hard and fast.
so no hazard assessment from quakes? I assume they looked at whether the containment would hold in a quake, but do you mean they didn't look at what would happen to the river?
Is next to Peregrine wines bottling plant but closer to the river?
The Council is very vague on location just saying 'between Victoria Bridge and Nevis Bluff'. Google maps doesnt show even a sign on the raodside but aerial views show some sort open excavation
Thanks for that. I didnt know the location of Victoria Bridge so assumed it was upstream of the Nevis Bluff.
Doesnt this report increase the recurrence interval for some faults but not the Nevis ? ( which makes it lower risk)
Of course these things sometimes are done to suit previous decisions. I would call it 'interesting' rather than definitive.
Here's the interactive sea level rise map for South Dunedin if anyone wants to play around with looking at how sea level rise will interact with the beach issues.
Otago Datum is msl +100m to avoid negative numbers around Dunedin. There's a lot of services in the mid to high 90's and out on the Taieri plain a lot of land in high 90's. That includes a large part of the airport at Momona.
Kettle Park will be just one of many issues that Dunedin will have to deal with. Sewerage is pumped out to sea not far from there and the associated infrastructure is all at very low level.
"Otago Datum is msl +100m to avoid negative numbers around Dunedin."
What does that mean?
Surveyor / engineer speak. Elevations are measured from an assumed origin point for convenience, in Otago's case it's 100m below msl as elevations well below have to be dealt with and negative numbers make calculations tricky, especially back in the day when they were done manually.
not quite sure if I'm getting that. If I look at a map and see a hill as being 500m, it's not 500m above sea level, it's actually 400m?
How elevations are presented can (and often is) different from how they are measured.
I have only a passing acquaintance with this area – but it is kind of fascinating.
Surveyors measure more than just land. They also will measure below mean sea level because there are features like reefs in the tidal area.
Surveyors are also the profession who measure things that ships can hit – like the tops of underwater volcanoes. And it is a profession that started long before computers or scuba gear, so they use an 0 point that was well below the humans ability to hit anything.
The elevations on maps are just as arbitrary. Perhaps the best way to describe what mean sea level is would be to say something like "msl is an arbitrary elevation point that was selected at some arbitrary point in time for a given country or area for the purposes of doing measurements from.
The rest of the country or area was measured from that point, peak to peak and peak to valley. – with a lot of cross-checking to discover the inevitable mistakes.
At any given time MSL may or may not approximate the actual local mean sea level because that is different in different places.
Of course it is a bit different now. We could just measure from radar, lidar or laser from the air or satellites. But your average surveyor doesn't have one of those in their pocket or truck.
Don't get me started on the arbitrary coordinate systems in use. For a start the earth isn't a sphere. It bulges. But also countries started to survey prior to agreeing on ordinate systems and there are differences between them. We have a NZ grid that is used for this country. So does everywhere else. The conversions are all slightly inexact because of underlying assumptions and small calculation or rounding errors in the past.
Plus of course even the global standards change. Just read this
I seem to have spent an inordinate amount of time doing translators from local ordinate systems into WGS84….
It really pays not to ask these questions. You could wind up down the rabbit hole like I did 🙂
Ha ha, I'm still glad I asked though.
"The elevations on maps are just as arbitrary. Perhaps the best way to describe what mean sea level is would be to say something like "msl is an arbitrary elevation point that was selected at some arbitrary point in time for a given country or area for the purposes of doing measurements from."
It's standardised though? How is that a problem if it's a constant and used across the country? What I thought Graeme was saying is that Otago uses its own reference point, which made me wonder about the height of mountains that sit half in Otago and half in another province using a different reference point
What you see on topo maps and Google Earth is in terms of msl. The Otago Datum is only used for engineering and surveying. Generally when a datum or origin below msl is chosen (most of NZ use datums at msl) it's because there's land, and services below msl. This is definitely the case in Otago with parts of South Dunedin and Momona being below msl.
hmm, tl'dr is I can ignore the original point about 'datum' because I'm not an engineer or surveyor?
tl'dr Large and /or important parts of Dunedin are below sea level to start with. And we know it's going to get worse.
thanks, I already knew that. I was trying to understand what you meant by,
"Otago Datum is msl +100m to avoid negative numbers around Dunedin. There's a lot of services in the mid to high 90's and out on the Taieri plain a lot of land in high 90's. That includes a large part of the airport at Momona."
What I'm getting from the conversation is that Datum is a thing that lay people don't particularly need to understand for this conversation.
The adoption of a datum below msl is the first part of engineering around the problem of being very low. Question is whether Dunedin continues with those efforts to engineer around the problem with sea walls, and eventually continuous pumping, or changes direction and gets out of the low lying areas and abandons them to nature.
The eastern Christchurch experience could be a guide to how this is could happen.
besides MSL is a fiction …. it's rising
I have the free version of the NZ Topo maps on my tablet ( PC as well) . Its essentially the old paper topographical maps 1 in to 1 mile ( now the closest scale ! :50,000) which had lots of rural surface features.
The touch screen means you can find the elevation at any particular point – not to surveyor standard- but close to the harbour in South Dunedin is 3m, further back is lower , 1m. So its not a lot freeboard as of course the mean sea level can be quite a bit lower than the sea level can reach. Spring tides combined with the shape of Otago harbour allowing the wind blowing from Port to the city to push the tide up on days with low bariometric pressure. A sea wall probably prevents sea inundation happening more often than it could, but the sea water still travels up stormwater drains or prevents the heavier rainfall draining away.
bite the bullet and dig it out while you can
Or the method the Dutch use ?
The lowest pt of the Netherlands is 6.75 m below SL.
The windmills main use was of course as pumps, an early use of wind power
Nah I can't see that working – partial seawalls aren't effective and total seawalls are not possible.
The harbour side is the lowest level, harbour sea wall possible with a lock for fishing vessels.
Coastal side could be protected by large concrete tetrahedrons to reduce wave energy as they have the small bluff created by dunes. Losing the beach is the price they would pay.
New Plymouth has a CBD protective sea wall to disappate energy , but their beach is further away so not affected.
yeah nah not doable imo – and a bit worse because of the waste of time, energy and resources – easier to move the centre of gravity of the city
South Dunners is a funny wee spot. Mum lived there for years and before that at Ocean Grove – the sea is relentless and the city will have to adjust imo
Dunedin can build a seawall across the St Clair/St Kilda beach space, and between the islands at Port Chalmers. Once sea rise starts we have to kiss our beaches goodbye anyway, there's no reason not to put in a Dutch style wall there.
Once you've done that we might as well reclaim a large chunk of the upper harbour to help pay for it all as the the upper harbour's health is already marginal
Really? It would barely last a storm or 3 if it could be built at all and for what reason? Waste of time and energy imo as the sea will just go around it anyway
By "sea wall" I'm more thinking of a Dutch-style dike – wall to wall from Andy Bay to St Clair – we'll have to dig it down to bedrock – sure we'll lose our beaches but with global warming they're already gone
I doubt it will save South Dunners – easier to move it.
Given the sea rising from beneath Sth Dunedin, and the problem with the high rainfall events, I think so too.
I once made the argument that low parts of Sth Dunedin should be depopulated (people assisted into new homes), and the area converted into a nature and recreation reserve. Possibly food production too if the pollution issues were sorted.
If we were doing the right things re GHG emissions instead of tinkering around the edges, we could be putting creative energy in how to adapt such spaces over time with sea level rise eg how to transition from suburbs to nature space where the sea level rises over a long period of time. Swamp trees first, then harvested and seafood later?
Is it the low level of the land that's the issue or the increasing wave action on sand and stone. Is that the same in the Netherlands?
In South Dunedin they've got both. Sea rising up from under the suburb, and on the beach side inundation from changes in the ocean. Not sure why this started to become a problem 10 or 15 years ago.
I lived in Taieri Mouth a beautiful spot just south of Dunedin for four years.
The New Brighton Taieri coastal rd is in danger of being inundated as seal levels rise.
Not big populations but communities that are going to have to adjust to a new normal in the years ahead.
South Dunedin is in danger as most of the area below the hills is lower that the coast and will again be in serious trouble as climate change and increasing storms force the local residents out with no plan in place for when they are not able to ever return.
Will the warnings be heeded before it is too late ?
And a compensation plan be put in place when insurance is not enough.
Christchurch is the recent example of what happens when disaster strikes.
NO we are living in the wrong country for that !!!
That's a shame, the Brighton to Taieri Mouth drive is a very attractive drive, it doesn't get the mention it should
Correction that should be Brighton not New.
BTW Dunedin's lowest point is actually it's airport, it already has dikes around it ….
One of the long term problems Dunedin will have to face is that the source of all that wonderful pristine white squeaky sand was shut down 50 years ago when the Roxburgh dam was built. We're on borrowed time as far as our beaches are concerned even if the sea stops rising
Global warming's sea level rise means we're going to lose our beaches, estuaries, and things like cockle beds, they will take hundreds of years to reform once the sea stops rising
Sand via the sea? Or where they trucking it in?
I heard the theory that the St Clair end of the beach was deteriorating because of the Clyde Dam, but this wasn't accepted as a significant cause by the authorities and scientists/engineers at the time.
The sand comes down the Clutha (or rather used to) and then is brought up the coast by the northerly coastal current.
The sand hills at St Clair/St Kilda were mined in the late 1800s/early 1900s for the concrete that built Dunedin – there was a railroad that was built down Andy Bay Rd then down Queen's Dr and then along to St Clair to recover this sand, the Kettle Park dump is how they filled in the hole. People used it as an excursion train to get to the beach at weekends – the railroad enthusiast's Ocean Beach steam railway runs on a tiny remaining section of this track.
Oh wow didn't know about the train. Cool.
It's why Andy Bay Rd is so wide, and why Queens drive doesn't match the grid of the rest of the streets in St Kllda
that is cool.
I thought the sand coming round from the outlet of the Clutha was rejected as a major issue for the beach encroachments. Are you saying that it is relevant, but it's just taken a long time for the effects to be seen?
No, I'm more saying that long term (for some unknown value of 'long') we're not getting any more sand from the Clutha. It may not be an issue right now but eventually it will be
got it, thanks.
South Dunedin was built on a marsh and the dunes have always been on the brink of failure.
Oh, and the bulk of SouthD flooding last time was due to surface water from the surrounding hills. Plus allegations of contractors not cleaning the drains (stanchly denied by council, of course).
Kettle park was a stupid place for a landfill, is full of hazardous shite, but on the plus side it stopped in the 1940s so probably doesn't have much plastic in it.
Good point. Probably a bit of metal, which they should reclaim when they move it. Not sure how much dodgy chemicals are in it, might depend on when in the 40s.
I think one of the odt reports mentioned asbestos and arsenic, but there'd be lots of lead, probably some mercury, maybe even radium and other glow in the dark stuff. The twenties and thirties were a wild and crazy time.
that's quite a mix.
Was this the dump for the hospital?
No, just stuff that was in common use at the time. Lead from packaging, roofing, and batteries and solder in electrical fittings. Mercury from household thermometers and some switches. Any luminous watch or clock or instrument dial at the time probably have had radium. And then there are the industrial uses for lead and arsenic and so on.
Probably a bit of coal tar in there as well from the old gas works. That's really nice stuff (not)
I have moved out of Napier now as the next heavy sea will breach tjheir "sea wall" along the marine parade of that coast.
Our old 1950's "Napier dump "is buried under the Highway 2 road heading north between Westshore and Bayview alongside the HB Airport a few meters from the sea, so they shouldve firtly excevated all the toxic rubbish at the site first as US did during their “superfund” Toxic sites campaign” still going on today.
We havnt even begun in ernest yet in NZ.
“Clean green” in NZ is a Myth.
Stupidly NZTA management are spending millions of taxpayers funds now just on resurfacing and widening the highway 2 road that sits on soil just a meter or so above the old napier Dumpsite so wait for yet another catastrope there next.
I now am in the hills 1600 feet up so I have now a boat there for future transport…
1931 Earthquake changed all the issue over high seas along Napiers seafront.
In very strong storms, sea water would smash into the front of the now Department of Conservation building on Marine Parade. Shops in Hastings St would also be flooded. -1880s
Earthquake moved up the land around Napier 2m or so , but for Clive further around the Bay they went down 1.5m or so. problem has moved.
Are the old ships wrecks still visible at Westshore high on the beach , which was once down at water levels?
Come and see what is happening along our HB Coast for yourself Dukeofoul as the whole beach front is far changed from the way you 'descibe it as'.
I recall it was around 1950/60's when you allude to ships partly submerged, and the '2 metre' raised areas are not there, as most ares are now below sea level of parts of our coast and inland areas, Pirimai/Onekawa/Tamatea/Greenmeadows east large residential zones of west Napier is eight ft below sea level, and ofter flood prone now the scene.now is totally different,.
No ships seen now either, anywhere; – the last one seen was many years ago was out at Whirinaki beach.
Westshore beach is now a deep banked 'gravel pit' seafront of rocks and fill to shore up the beachfront from sea inudation, and heavy seas, so it is not the old scene of golden sand dunes and 'shallow safe wadable water levels' of yesteryear where you could walk out to the 'Iron Pot' and 'perfume point' areas of south east westshore..
Come and visit and see the carnage of climate change going on here.
"Pirimai/Onekawa/Tamatea/Greenmeadows east large residential zones of west Napier is eight ft below sea level"
You are telling lies there.
These are maps from recent Lidar mapping, the areas are ALL above sea level. – not a lot. But nothing like your false claim of being '8ft'
Any way my story was about the beaches themselves. Its complicated
Until the 1931 earthquake, when the seabed and land were lifted nearly 2m, Westshore was a thin gravel spit.
The changing of the river mouths may have contributed to the loss of sand, and the gravel extraction near Awatoto had taken large quantities
The breakwaters have changed considerably since my time
Why do you say that? Why is it not simply incorrect or a “false claim”?
Good point. We all can make mistakes in these things , but its so far out of wack and the main thing , its cleangreen who does it all the time.
I grew up in that area , my father worked for a time with the old harbour Board. Its got great memories still and I just hate it when bluffers come along and misrepresent it all.
Fair enough. I believe cleangreen is trying hard and well-meaning and I’m inclined to give them the benefit of doubt and a friendly and polite correction of facts is all that’s needed. However, if it continues, after a few warnings, I may have to change my thinking 😉
This very recent comment by cleangreen is shaping my current thinking and relative ‘goodwill’ towards them: https://thestandard.org.nz/open-mike-11-08-2019/#comment-1645477
So many, so, so many…
Yeah, Fox seems to just be the tip of the shitberg.
I'm wondering about Taranaki where 245T – Agent Orange stuff that was manufactured.
https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=3590458 Dioxin at Vietnam levels near pesticide plant
In a statement yesterday, Dow AgroSciences said the study findings concerned exposure 40 years ago to operations that had long since ceased.
No one tested had been found outside the range of what would be considered normal background levels of dioxin in other studies.
Dow's 2,4,5-T was the most heavily used spray for gorse and blackberry on New Zealand hill country farms in the 25 years to 1987…
Thirty-nine years after a midwife saw "horrific" deformities in babies born near a New Plymouth chemical factory, an official study has found dioxin levels in the blood of local people as high as those in people sprayed with Agent Orange in the Vietnam War….
The latest report, by the Institute of Environmental Science and Research (ESR), ends almost 40 years of official denials that the dioxin used in making 2,4,5-T at New Plymouth may have affected the health of local people…
Men aged 50 to 64 had dioxin levels 3.9 times the average for their age group, women aged 65 and over three times the average, and women aged 50 to 64 twice the average levels.
A study two years ago of dioxin levels in soil around the Dow plant found higher levels in an area extending about 1km east of the factory and about 400m southwards, in line with prevailing winds.
ESR concluded that the dioxin was spread by air in the years before 1975, when the company started incinerating its wastes.
(So in the years before 1975 before incinerating, did it bury its wastes?)
Some personal testimony.
Just get the Army engineers (would prefer the MoW, but since they have gone the way of the Moa) to laid out some HESCO’s, fill it with a pre- mix and cement slurry mixture, and backfill with rock? Might lose a good chunk of the beach in the process, but it would give the DCC, Regional Council and those in Wellington time on how to remove old the tip before it’s ends up like another Fox river disaster .
Are those reusable?
There's something uncomfortable about using cement (with its GHG emissions) to solve climate change fallout.
Cant see any significant redirecting of infrastructure away from FF that dosnt involve substantial cement input (or FF for that matter)
Yes, but there are lots of uses of concrete we don't need that badly and that we should be looking for alternatives for given the GHGs associated with cement.
eg, using gabion baskets stabilise the sand dunes while they move the dump is a good idea, because it may prevent a disaster. Even better if those are reusable.
Using concrete to building houses because of convenience probably isn't a good idea (thinking foundations here). I haven't looked at the cement uses by GHG emission amount though, so I'm speculating to provide an example.
Most city dumps like Napier had industry dumping their toxic waste all those years ago,as I should know.
I grew up alongside the new Napier Dump on Battery Road during 1951 to 1957 and often witnessed dumping of waste tankers of ‘acetone’ https://pubchem.ncbi.nlm.nih.gov/compound/acetone from ‘Industrial gases’ and other industries there.
Our pet cat fell into a pond full of white acetone and died afer from lots of bleeding boils on her back and it was painful to see.
We must begin the retreval of all waste buried in dumpsites alll over NZ now before the story becomes more toxic to discuss.
To Weka @15.1
Sorry for my late reply as I caught up on a few on the giggle box and I start to read a book last night.
Yes the Hesco barriers are reusable if the are correctly put in place and whatever is use is correctly compacted and the cloth/ hessian is biodegradable. With my idea of using a pre mix and cement slurry to fill the hesco barriers may not allow them to be reused unless it’s fill with sand and backfill with rocks as another solution?
My suggestion of using a pre mix and cement, was because our elected and non elected government officials take an awful long time to make a decision before we even consider various NGO’s/ IMG’s/ NIMBY’s sticking their two bob’s worth farther delaying the process and therefore making the whole project of moving the old dump from a simple process to a more complex process which = more delays = more money wasted and wasting time/ delays especially if private sector/ contractors are involved.
Thence why i would like to see the MoW reform as they were a one stop shop, but the Army engineers are the next best thing to the MoW atm as they are also a one stop if Pollies still haven’t run the Army engineers farther into the ground like the bastards did into the 90’s with NZDF as a whole.
Atm I believe cement base products and coking coal are necessary evil, until we found an alternate way of building things without effecting the environment.
Ps. I would like to say welcome back Weka, as I did enjoy reading your posts over the years and I hope you had a good break or whatever you did while you were away from the TS.