Southerly: That CERA Rumour
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Mark Quigley at the Share An Idea expo in the weekend discussed the park along the river idea a little. He's a lecturer in geosciences at UC and has become a bit famous for giving lucid analysis of the earthquakes. He lives in a badly affected area, with only a few houses on his street still inhabited. (Disclaimer: I live in Sydenham, so probably won't be affected if the rumours David talks about become a reality, although we got our fair share of liquefaction.)
From what I understood there seems to be the added factor of climate change/sea level rise to contend with - as you say David there are areas that are now below the level of the river and levees will only be useful up to a point.
He was suggesting (I don't think he has any official role in relation to CERA) that we may have to plan for some alternatives for the worst affected areas along the river. He was also clear that we have to avoid "a half eaten doughnut" of a city, with people living in the east ending up living in a sprawling west of the city and a dead centre.
One alternative might be to move well-performing houses in the east to under-used land still in the east but closer to the centre of town - replacing ugly light industrial areas with potentially vibrant residential areas, ensuring along the way that you plan gardens, pubs and dairies etc.
The resulting area along the river could be a very attractive asset like a long skinny Hagley Park, that would enhance land values in the surrounding area.
It doesn't seem to be viable (as per Rod Carr's opinion piece in The Press in the weekend) to move the UC to the centre of town. But Quigley suggested a tram/light rail link from UC to the sea at New Brighton that would mean young people would be attracted to live in the centre city for the inner city lifestyle, but would have easy access to the University (and the sea for surfing between classes). This would also enhance the beach as a destination and place to live.
Lilith __, in reply to
From what I understood there seems to be the added factor of climate change/sea level rise to contend with – as you say David there are areas that are now below the level of the river and levees will only be useful up to a point.
This would also enhance the beach as a destination and place to live.
Don’t see how both these can be true at the same time. And most of greater Chch is below mean sea level. Sure, we have to plan for sea level rises, but abandoning land beside the Avon while building in Brighton doesn’t sound like the way to go about it.
Martin Lindberg, in reply to
..it's your own fucking fault for being so stupid
There were so many comments like this after Katrina. Mostly in geek forums. I imagine it's from a lack of understanding of how cities are formed. Well, outside of playing Civilization, of course.
we have to plan for sea level rises, but abandoning land beside the Avon while building in Brighton doesn’t sound like the way to go about it
A fair point, although I think the issue Quigley was talking about was the increasing threat, because of sea-level rise, of inundation along the river due to flooding - e.g. when there's lots of precipitation and a high tide, which wouldn't be such a problem in Brighton. However,
most of greater Chch is below mean sea level
this is not the case. Chch is fairly low and flat, but the square is/was about 6 metres above mean sea level and the airport 37 metres above (meaning the airport used to be above the Cathedral's spire IIRC).
Lilith __, in reply to
the square is/was about 6 metres above mean sea level
OK, I stand corrected on that point, I should have checked it before posting! And obviously riverside properties are at risk of flooding, as they have always been. The lower Heathcote used to flood along Richardson Tce on a fairly regular basis, before the Woolston Cut was put in. But rises in sea level *will* threaten beachside suburbs, particularly in stormy conditions.
Quigley suggested a tram/light rail link from UC to the sea at New Brighton
Personally, I'm a big fan of this idea. I was in Dijon for a while last year, a city of similar size to Christchuch both in terms of population and land. It also has a slightly smaller area a little like the CBD (but in their case, originally bounded by the city walls, which are now 4 boulevards, cf. avenues) They are building a tram that runs from their big box retail precinct to the CBD via the university and hospital (in Dijon's case, these are both located on the edge of the city, having outgrown their more central locations). This intersects with another tram that serves different poles of the city.
Francis Greensalad, in reply to
Lots of flooding in New Brighton last night. Into Hawke street and keys road. It was a spring tide. But it was fine weather.... what happens when we get a storm event on top of it? Something has to be done fast . The new small stop banks will not hold. My daughter lives 120m from river and parents live 170m from river. I think their houses will be flooded this winter....
Sacha, in reply to
There were so many comments like this after Katrina. Mostly in geek forums. I imagine it's from a lack of understanding of how cities are formed.
Or a lack of empathic ability.
Oh where shall I put this?
WAAAYYYYY of topic but, rather humourous!! And not a party political statement from me!!!
So, sorry David, for want of a better place.....
All Dunne and Dusted.
I think that there are two important points here.
The general level of the riverside land is lower than it was before the earthquakes and the riverbed is higher than it was. That means that the area of land likely to be flooded in the event of a springtide coinciding with a heavy rainfall event is close to what would have been expected from a 3 metre tsunami prior to the earthquake changes. In that event the entire expressway from Bromley to Shirley Golf Course would be underwater along with half of Avonside, Dallington, Avondale, Aranui and South Brighton.
Once the cost of flood protection/mitigation works are added to the land remediation costs it may be cheaper top build new roads and pipes for new suburbs on more stable soils than to rebuild the existing pipes and roads with a deep enough basecourse to resist a couple of minutes of shaking from an Alpine Fault earthquake.
IMHO the costs probably will turn out to be similar so the decision really comes down to the social and community costs of the two alternatives.
Lilith __, in reply to
OK I'm still blushing about my sea-level gaffe and so am in no position to be criticising the assertions of others...but kevyn, do you have sources to back this up?
One of the things I like about David's original post is that he's worked out the figures and so can make a meaningful comparison between land remediation vs. resettlement, and his figures strongly favour remediation.
If the riverbanks are lower, and the riverbed higher, does anyone know by how much? And wouldn't dredging the river to remove liquefaction silt solve much of the problem?
I struggle to imagine that the cost and difficulty of relocating the entire population of whole suburbs could compare with the cost of ground repair and flood protection works, which would have the additional benefit of protecting adjacent areas.
Rumors can be upsetting, this is true. I heard a rumor once that South Canterbury Finance was the one of the best run companies in the lending game. While the above article makes a case against a rumor and suggests engineering solutions to the whispers and indeed, it's a well argued point of view from a property owning pressure group, who appear to not want to change.
Christchurch faces many challenges, just exactly what parts ought to be rebuilt and just what the future of the city is, remains unclear. Continued aftershocks, Dr Berryman from GNS said these could go for 30 years and what damage may this cause? But whatever the outcome in the earths crust, the possible rebuild is only made viable by the injection of vast amounts of social cash from all New Zealanders (Govt, Eqc etc).
Questions of social fairness and equity will need to be carefully considered. It may be desirable to have a home beside a river, or at the top of a cliff as close to edge as you dare, but the moment owners start asking for collective money to sure-up, housing land in questionable locations, then I think we have some deep issues. Will some land become more valuable as a result of "shoring-up" works, while other parts will be abandoned because it is too costly to fix the land?
In regards to retrofitting new foundations I think the costings are underestimated by the author. In addition these sorts of works will only be viable if there is a new central business area is built. Because otherwise there will be no reason to live there and enjoy the ducks. One of the bigger questions we all face in NZ are the brutal facts of globalisation and just exactly what role a re-bulit Christchurch might play. As we have been warned so many times selling each other expensive housing besides rivers will not earn our way in the world.
In an bleak first interview on National radio new CERA CEO Roger Sutton mumbled something about his vision for an ice skating rink in the centre of Christchurch, as a focus, it could be a paddling pool in the summer, a place for people to "gather". It's this sort of muddled thinking that makes me think the river bank fissures should just run their course. I'm all for, the newly proposed park land along the Avon, if nothing else, it will shake-up the population and cause them to react with renewed vigor.
It's time to be forward looking, the heritage beside and along the river was from the coal age. In an age of global warming we should be very careful when we look at the topography and make our social decisions on what was New Zealand's second largest city. That right there, might just be the only heritage fact left to ponder while walking along Avon Park walkway.... near the old site of Christchurch City.
Sorry for being so grim.
Robert Urquhart, in reply to
In regards to retrofitting new foundations I think the costings are underestimated by the author.
Oh, I think David is sadly intimately familiar with the cost of retrofitting new foundations to a riverside house in Christchurch.
David Haywood, in reply to
I assure you that I am not a “property owning pressure group” – you can read about me here.
You say that you are in favour of “the newly proposed park land along the Avon”, but at what monetary cost? By my calculations the cost would be upwards of $385,000,000. That’s an awfully expensive park – even when it serves the additional psychological function of “shak[ing]-up the population and caus[ing] them to react with renewed vigor”!
I’m not arguing to spend money on some group of propertied elite – I’m arguing that it is clearly cheaper to remediate the land along the river rather than demolish (although, of course, there may well be some specific areas where it is not economic to remediate the land). And, of course, regardless of whether or not we engage in mass demolition, the (insured) propertied elite will still retain the value of their homes, either in the form of their existing property or in terms of their insurance payout.
Don’t apologize for feeling grim! We all have those days – especially when you live in post-quake Christchurch. But it is important to make our decisions based on logical analysis rather than emotion – otherwise we’ll end up with a second (or should that be third?) disaster in Christchurch.
David ‘Not a Property Owning Pressure Group’ Haywood
P.S. I’ve done a fair bit of conceptual design work on retrofitting those foundations, performed basic sizing calculations, and obtained quotes from EasySteel. I’m pretty confident that those estimates are in the right ballpark.
new CERA CEO Roger Sutton mumbled something about his vision for an ice skating rink in the centre of Christchurch, as a focus, it could be a paddling pool in the summer, a place for people to "gather"
That might sound lame on first acquaintance, but if this were to be 1/10 as cool as the Miroir d'Eau in Bordeaux, then you are seriously under-selling this man. It is the heart of a modern re-vitalised city, and is just amazing at all hours of day and night (seriously try this second link, and you'll see something that both looks amazing, but is also really heavily used).
Islander, in reply to
Tht second link worked - wonderfully!
Now, all we need to do - is do it AND persuade one of the 3 resident taniwha to - well, take up residence-
Miroir d'Eau...mmm and those granite tiles in the square, cause I'm sure we'd want to recycle them...sure, "grand designs" but as I shiver in the north easterly gale, it's no place to gather, it was enough with my toddler in the gardens back in the day. And as for the other days, the howling westerly will just create waves, there will be no mirror. Sorry it's just too grand, great for it's hemisphere, but not roaring 40's.
I'm just not sure anyone at the CERA should be putting forward civic "gather" projects, the role is to make decisions, proper economic ones as you say David, and to facilitate matters between Council and Government and Community. I Think Brownlee said after the September quake he didn't want a Top Down Politburo in charge of the repairs....leave it to the market he said. umm...so what is CERA then...skating anyone? Perhaps, it's because under Bob the Council has sunk under it's own spin. Actually in this hemisphere what way does water go round the plug hole?
So may I ask David, why is your focus on the area you live, do you propose all rivers and streams in Chch be "sured-up"? If so, what is the cost? If there are not enough resources, how would one decide, for example to exclude the Heathcote over a "sure-up" of the Avon? How much shoring-up secures the future of the city? I think as soon as we get specific about location then the glasses become somewhat fogged.
Oh and..."Easy Steel" is that a Fletcher Company, part of the social fabric? So old school when it comes to monopoly trading in the market.
Emma Hart, in reply to
Shulgin, I'm sure your apology and admission that you were completely wrong about David's property owning pressure group agenda is much appreciated, especially for the way you didn't just breeze on and pretend you didn't say it.
So may I ask David, why is your focus on the area you live, do you propose all rivers and streams in Chch be "sured-up"? If so, what is the cost? If there are not enough resources, how would one decide, for example to exclude the Heathcote over a "sure-up" of the Avon?
But here's my problem. What part of "remediation is cheaper than abandonment" are you having trouble with?
Lilith __, in reply to
I have to say I love(d) the pond in the Arts Centre's North Quadrangle, the way the water looked different depending on the light and weather conditions...the Miroir d'Eau is much grander -- amazing!
James Green wrote:
... if this were to be 1/10 as cool as the Miroir d’Eau in Bordeaux, then you are seriously under-selling this man.
That's spectacular -- it'd be brilliant in Christchurch!
So may I ask David, why is your focus on the area you live...
Because that happened to be the area that the rumour was about, i.e. it wasn't about Heathcote or anywhere else.
... do you propose all rivers and streams in Chch be “sured-up”?
It it's more cost effective to do land remediation than demolish then we should do land remediation. If it's more cost-effective to demolish than do land remediation then we should demolish. But this should be worked out on a case-by-case basis along the rivers (or anywhere else). It isn't sensible to declare to either remediate or demolish without looking at the costs.
how would one decide, for example to exclude the Heathcote over a “sure-up” of the Avon?
You wouldn't decide for a whole river. You would do it on a case-by-case basis in sections of the river looking at the cost-effectiveness for each section, i.e. whether demolishing or remediating was cheaper.
I think as soon as we get specific about location then the glasses become somewhat fogged.
Not at all -- it's all based on economic analysis within the framework of what is possible from an engineering perspective. It's just a matter of working out what is the most cost effective solution.
"Easy Steel” is that a Fletcher Company, part of the social fabric? So old school...
Yes, EasySteel is part of Fletchers. But I didn't mention it because they provided me with the cheapest quote. I mentioned it because Hugh Fletcher secretly funds this blog (he was at King's College with Russell Brown), and we have explicit instructions to mention Fletcher-group companies at least once in everything we write. It's all a giant conspiracy.
David Haywood, in reply to
One thing I saw being pushed after the Loma Prieata 'quake was 'liquefaction proof houses' so they could keep building in these reclaimed spaces by the Bay. The basic idea is that you build your concrete foundation like a boat - it's closed and deep enough that it will float when the surrounding ground turns liquid, add a gas connection that will safely break away and when the big one hits it's "avast me hearties!" and you're off, for a metre or two
Thanks for some fascinating comments, Paul. The thing I've never been able to work out about the floating system is how you relevel it after a quake. I'm sure there must be a way -- but I can't seem to find anything about it.
Fooman, in reply to
So may I ask David, why is your focus on the area you live, do you propose all rivers and streams in Chch be "sured-up"?
Do all rivers and streams in Chch need shoring up?
If there are not enough resources, how would one decide, for example to exclude the Heathcote over a "sure-up" of the Avon? How much shoring-up secures the future of the city? I think as soon as we get specific about location then the glasses become somewhat fogged.
The descision to "shore up" versus abandonment is the focus of the orginal article. You are unaware that the resources are there (if the property was insured) - the cost per dwelling is to be met by the combination of private insurance (i.e. overseas re-insurance companies) and the government (EQC reserves and other spending). The only impact of Heathcote vs Avon would be land value - the higher value sections would be more expensive to abandon (recompense the owner). The glasses do not get fogged with such detail - focus is obtained by such information.
What David has done is to provide a 1st estimate of the costs (based on personal circumstances, and years of boring lectures on engineering management) and extrapolated, using researched data and actual costs to show that, at least one method of remediation is likely to be significantly cheaper in total than total abandonment.
This is the same sort of process that CERA will be doing, in conjuction with engineers, architects, builders, to get the best idea of what can be done, and the financial cost.
As for the snide comments about EasySteel - if they are cheaper than KiwiSteel, or Steel and Tube, or one of NZ Steels Chch distributors, all the better. Not exactly monopoly trading innit?
Gregor Ronald wrote:
And I'm darned if I want to live in Rolleston/Pegasus/Wigram - we moved to Christchurch 15 years ago and made a conscious decision to live near the city centre.
Good point -- yes, to do the cost analysis properly you need to calculate in the added fuel/roading costs for those displaced away from the inner city suburbs.
Glenn Pearce wrote:
Question though, is the land remediation viable without first removing the structures (houses) and infrastructure (roads) ? Obviously it's an option in a Greenfields site, but in an already built up area ?
Yes, it (mostly) is. The road runs along both sides of the river bank, so you'd do all your compaction work there. Luckily for CHCH the earthquake has already conveniently torn up both the road and the sewer system along the optimal route.
Fooman, in reply to
relevel it after a quake. I'm sure there must be a way -- but I can't seem to find anything about it.
Re-levelling a slab has been done by pumping grout underneath the low side until the facade of equilibrium is recovered
Sacha, in reply to
especially for the way you didn't just breeze on and pretend you didn't say it
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