Posts by David Haywood
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OnPoint: Budget 2011: A Credible Path to…, in reply to Sacha,
The more obvious target is the loony ‘roads of National party significance’ motorway building programme. It’s an $11,000,000,000 taxpayer investment in last century’s networks that totally ignores even the current price of oil, let alone its future...
Putting on my energy engineer's hat, I'm constantly gobsmacked that a bigger deal isn't made of this. How can the government be selling off strategic infrastructure in energy at the same time as taking full ownership of luxury-length roading that massively adds to the country's energy problems (in the form of liquid fuels imports). If Steven Joyce absolutely insists on building unnecessary motorways then why doesn't he hand them over to the private sector to build them as toll roads?
I suspect that, in future decades, Stephen Joyce will be held up as one of our most disastrous politicians ever.
On the bright side, I now find that I can walk the baby and comment on Public Address at the same time. Thank you Android phone!
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Southerly: That CERA Rumour, in reply to Megan Wegan,
Fast, and smooth.
Oh, and in related news, Megan, I discovered today that the new RNZ CHCH studios no longer have double beds. So our shared dream of broadcasting from bed is an opportunity that has been missed forever.
Also, with regard to your Rolleston comments earlier in this thread, I’ve received an email from a Rolleston resident complaining that I used a “contemptuous tone” when mentioning Rolleston to Kathryn Ryan today, and that people should “stop picking on Rolleston”. So I’m just passing that message on to you. Either an on-air apology or an RNZ organized public meeting/apology in Rolleston might be appropriate.
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Southerly: That CERA Rumour, in reply to kevyn,
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.
I admit that I haven't yet got my head around the river level changes. How much of the rise is due to new sand in the river bed; how much to the fact that the banks have moved closer together; how much to the land slumping beside the river?
If it's mostly the first two factors, then -- as Lilith says -- dredging may be a practical solution. In the event of the third factor, the cost of stopbanks may not be such an issue (after all you'd have to deliver a lot of soil/gravel to the banks anyway if you go the vibrocompaction route), but the consequences of stopbank failure would be pretty bad.
Do you have hard data on this? If so, I'd be *very* interested to see it.
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Southerly: That CERA Rumour, in reply to Matthew Reid,
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.
Thanks for that, Matthew! That's a very interesting idea that I hadn't come across.
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Southerly: That CERA Rumour, in reply to Russell Brown,
... part of me regards the sheer breadth of Mr Haywood's skillset as bordering on the indecent.
Ha! -- and yet I frequently feel like the stupidest person on Public Address. Perhaps I have breadth but not depth or something.
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Southerly: That CERA Rumour, in reply to Islander,
No worries, Islander. Glad to be of some help! And -- now that (amazingly) both my children are simultaneously asleep -- I have time to mention how pleased I was that Arapeta Ota had provided such great licking material for your younger relatives. He's been flying out the door recently, and I have happy visions of him being roundly licked by many of the younger citizenry of this nation.
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Southerly: That CERA Rumour, in reply to Raymond A Francis,
My call would be to encourage you all to drift south by making sure the infrastucture is there
And if you don’t want too, next time it shakes tough luckMy point in writing this – obviously made not very clearly, alas – was to show that it is more economic (for the river taken as a whole) to remediate the land rather than demolish and rebuild elsewhere. The wholesale abandonment of the entire city of Christchurch (much of which is quite undamaged) would be *phenomenally* uneconomic.
And, of course, the remediated land should survive any future earthquakes, so we shouldn’t need anyone to console us by declaring “tough luck” (and other such touching sentiments) next time!
In fact, with the remediated land, Christchurch may be one of the safer cities in comparison to Auckland (built on a volcanic field), Wellington (built on a fault line), and Dunedin (much of the housing on sandy soil within the quake zone of the Alpine Fault). Tsunamis would probably have a big death toll in all these places, of course.
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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.
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Southerly: That CERA Rumour, in reply to Paul Campbell,
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.
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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!
Shulgin wrote:
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.