Southerly by David Haywood

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I was going to write about how we found our house.  To tell you the story of how it took us nearly two years to find just the right spot to make a home.  To tell you how we visited universities all over the world who were keen to recruit my wife -- in New York City, Berlin, Stanford, and York -- and then decided that the best place to raise a family was back in Christchurch beside the Avon River.

But all that has rather flown out of my head this morning.  Instead I'll tell you about our insurance company.

Naturally, when we eventually found the right place, we were very careful to insure it properly.  I am a great believer in insurance -- and, being a very old house (100 years old next year), I made sure that we purchased total replacement cover.  For old houses the book value is usually much less than the total replacement cost; high ceilings and double-hung windows have become expensive in the modern world.

Indeed it was one of the things that has consoled us through three massive earthquakes; through the times we lived without sewerage, water, and electricity; through the six weeks when we were evacuated from the city with a young baby and a three-year-old.  At least, we thought, we had total replacement insurance -- if the worst came to the worst we would be able to rebuild a house of the same quality and size as we had before.

And yesterday, of course, the worst (as regards to the house) happened.  A man called Liam phoned us to say that we had nine months to leave the property.  Although our house was repairable and the land comparatively undamaged, the state of the surrounding houses meant that we had to go.  Fair enough -- and, of course, at least we had total replacement insurance.

But when I phoned Tower Insurance this morning to initiate a claim -- guess what?  They found a loophole.

Tower Insurance maintain that the house is not a write-off.  They maintain that they are only obliged to repair the house -- not to honour our insurance policy for total replacement.  They say that just because we won't be allowed to live on the land, and that the house will be bulldozed, doesn't mean that the house is an insurance write-off.  Sorry, they say, but what the government mandates with regard to land is nothing to do with them.

Tower say that they will only pay the book value on the property -- the very thing that we have been paying insurance for years to avoid.  And by Tower's own numbers this leaves us nearly $200,000 short of the money required to replace our house.

And what about the land?  The news isn't great there either.  Gerry Brownlee has done an outstanding job of upgrading the standard EQC payout -- and I sincerely thank him for that.  But unfortunately the area-by-area system used to determine rateable value means that land on the river bank is underestimated in comparison to market price.  In our case, the rateable value of the land is $80,000 less than that assessed by a registered valuer when we purchased the property. 

So it's been a bad morning.  And I suspect it's going to be a bad few years.

Perhaps the most common theme on the shareanidea.org.nz website (a council-run service for collecting ideas on the rebuilding of central Christchurch) is the suggestion to dramatically improve the city's cycling infrastructure. Although only one submission actually mentions the word 'Copenhagenize', this would be the verb that many engineers would employ to describe the overall process of designing a cycle-friendly city.

If you haven't come across it before, 'Copenhagenize' arises from an urban planning philosophy that was implemented in Copenhagen in order to promote the use of bicycles (and also walking) as a form of urban transportation. The success of this planning philosophy in Copenhagen has been astounding -- with 36 per cent of its population now making their daily commute by bicycle.

The shareanidea.org.nz website only permits a maximum of 140 characters for each submission, which doesn't allow a lot of room to explain why Copenhagenization might be a good idea. So I thought it might be worth giving a quick overview of the research on this topic.

What was the original inspiration for Copenhagenization?

Copenhagen's flat landscape makes it ideally suited to cycling, and for the first half of the 20th century the bicycle was the most popular form of personal transportation (excluding walking).

During the 1960s, however, the increasing affordability of motor cars led to a decline in cycling, and it was only with the 1970s energy crises that the city began to consider ways of getting its citizens back onto bicycles -- as a means of reducing fuel usage and curbing air pollution.

In order to achieve this, the local government in Copenhagen adopted a policy of encouraging cycling via a safe, convenient, and widespread cycling infrastructure.

But isn't the natural geography and climate of Copenhagen much more suited to cycling than Christchurch?

In terms of natural geography, both Copenhagen and Christchurch (apart from a couple of hill suburbs) are extremely flat cities that are equally well-suited to cycling. But -- from a cyclist's perspective -- Christchurch actually trumps Copenhagen in the crucial climate data with:

• A much warmer winter (average winter temperature of 9 degrees Celsius in Christchurch as opposed to 0 degrees Celsius in Copenhagen).
• Much lower annual rainfall (an average of 360 millimetres in Christchurch as opposed to 587 mm in Copenhagen).
• More sunshine hours (an average of 2,025 sunshine hours in Christchurch as opposed to 1,603 sunshine hours in Copenhagen).

In fact, in terms of suitability for cycling, the only advantage that Copenhagen has over Canterbury is the cycling infrastructure.

Okay, but what advantages would Copenhagenization give to Christchurch?

Short answer: it will save us loads of money.

Despite being so suitable for cycling, Christchurch has the highest car ownership rate of any city in New Zealand and over three-quarters of the working population commutes in a private motor vehicle (only six per cent of Christchurch commuters travelled by bicycle on census day March 2007).

If the citizens of Christchurch cycled at the same rate as those of Copenhagen (given Christchurch's employed population of 162,243, our median commuting distance of 5 kilometres, the typical New Zealand vehicle's fuel consumption of 10 litres per 100 kilometres (with a conversion factor of 1.25 to convert from 'combined' to 'urban' fuel consumption)) then this would save the annual equivalent of 14.6 million litres of 91-octane petrol.

At current retail fuel prices, this equates to nearly 31.4 million dollars per year -- a significant proportion of which would have been sent overseas (with a detrimental effect on New Zealand's balance of payments). According to the NZTA, the increased population of cyclists would also save about 11.7 million dollars per annum in "environmental benefits" such as congestion reduction and decreased vehicle emissions (the NZTA values these at $0.10 per kilometre for each motorist taken off the road during peak traffic conditions).

In other words, the Christchurch economy would have to pay about 43 million dollars less each year in fuel and environmental costs to get its citizens to and from their place of work.

This seems enough of a reason to take a closer look at the possibility of Copenhagenizing Christchurch, but the health effects of cycling are where the real savings to the economy start to kick in. A NZTA research report from 2007 carried out an in-depth investigation into the economic health benefits of various forms of 'active' transport -- examining the preventative effects on diseases such as diabetes, cancer, coronary disease, and even depression. Assuming that the same proportions of physically active people in the general population are also represented in cycle commuters, then the monetary value of encouraging the citizens of Christchurch to cycle like Copenhageners amounts to an astonishing 87.5 million dollars per annum.

Are you keeping track of all this? Add it all together and you get a total savings to the economy of 131 million dollars per year -- quite a sizeable chunk of change for a small city (in which, by comparison, the city council's 2010 rates revenue is only 256 million dollars). And this is not even to consider such items as reduced road maintenance, vehicle repairs/maintenance, and parking costs.

But wouldn't it take much longer to commute by bicycle?

It would depend. In my experience with a regular 11.5 kilometre (each way) commute during Christchurch's rush hour, it only took five minutes longer to travel by bicycle than in a car. On a bicycle you can pass an awful lot of motor vehicles queued at traffic lights.

But a better way to answer this question would be to consider the length of time that people consider reasonable as a commute. The average commuting time (one-way) in New Zealand is 20 minutes, which is probably a good indication of what Christchurch citizens might tolerate.

It's difficult to estimate how fast an average person would cycle when commuting in Christchurch, but the average cycling speed through urban areas in Holland is 15 kilometres per hour. Using this figure we can predict that the average commuting cyclist would likely travel five kilometres in the average New Zealand commuting time of 20 minutes.

And conveniently, as mentioned already, five kilometres is the median distance commuted in Christchurch. So, on this basis, the length of time that would be spent commuting by bicycle in Christchurch should be entirely acceptable.

So how real are these numbers?

There are a lot of unknowns in assigning economic costs when dealing with the unpredictable human personality (and I'm always slightly suspicious of such studies). For example, it's possible that significantly fewer people would cycle when it's either very hot or very cold, or -- despite the excellent rain-gear now available -- on the comparatively few rainy days in Christchurch. This would have the effect of reducing the economic savings given above.

On the other hand, it's very likely that the census data grossly overestimates the number of existing cycle commuters in Christchurch. It's also likely that a significant proportion of people may dispense with their second car when they start to commute by bicycle (saving at least $1,500 per year per household in depreciation, registration, WOF, repairs, and maintenance) -- which would have the effect of markedly increasing the savings given above. Furthermore, the 'employed' population used in these calculations does not include the 19,000 students enrolled at the university of Canterbury or the 20,000 students enrolled at CPIT, which could increase the annual savings by as much as 30 million dollars.

Another possibility is that only very physically fit people would commute by bicycle, which would significantly reduce the economic health benefits. But when you look at cities such as Amsterdam or Copenhagen or Munich you see a very broad range of cyclists -- from octogenarians to new-born babies (in carriers) and people of every size and shape. It's hard to see why Christchurch would be so different.

And, of course, there is likely to be a mismatch between the median distance commuted by a predominantly motoring workforce versus a bicycle community. My suspicion is that those with the shortest commuting distance would be more likely to 'convert' to cycling. But it must be remembered that these calculations are only for pure commuting travel -- it doesn't include weekend journeys or diversions to run errands while commuting, which are more likely to be undertaken on a bicycle when people are already regular cycle commuters.

In short, the numbers given are a ballpark figure: the true value could easily be plus or minus 50 per cent.

What sort of cycling infrastructure should we build?

Like Copenhagen, we need to build cycle infrastructure that will keep cyclists safe, that will be convenient for cyclists to use, and that is widely spread across the city so that cyclists can get where they need to go. This includes:

• Building cycle paths that will safely separate bicycles from motor traffic -- in addition to the current cycle lanes (which are just painted markings on main roads). With 600 kilometres of post-earthquake road repairs required in Christchurch there may never be a cheaper time to do this.
  
  

  Above: A proper cycle path in Copenhagen.

• Building green corridors to route cyclists through the (more than 740) parks in Christchurch. This would help to separate bicycle commuters from car exhaust fumes (from my own experience with cycle commuting I know that I'd rather take a slightly longer path through a park than a shorter route via a car-clogged street).
• Build the necessary traffic lights and cycle parking for bicycle commuters. And, as much as possible, integrate cycling with the public transport system (as is already done on the Lyttelton ferry and buses).

• Consider designating some streets to be 'cycle roads'. This would involve closing the roads to motorized through-traffic, designating a 30 kilometre per hour speed limit for residents and delivery vehicles, and marking-out large cycle lanes that physically dominate the road. This is a very low-cost option (indeed it would reduce the cost of maintaining existing roads) that will never be cheaper than in the post-earthquake rebuild.
• Consider some radical approaches to encourage commuting by bicycle. For example, it would be technically possible to 'reverse toll' cyclists (in conjunction with the existing Metro card system) using electronic readers on cycle paths. Cycle commuters could then be rewarded with free bus travel that could be used for longer journeys or during bad weather.

Of course, for cycle paths, cycle lanes, and green corridors it is critically important that they should connect to the existing roading network in a safe manner.  Most accidents occur at intersections, and a properly-designed cycle infrastructure will make use of a variety of sytems to meet the distinct requirements at any given location.  No system is inherently safer than another (a good overview of cycle infrastructure design as it relates to Christchurch is given here; some of my own thoughts on this topic are here).

In conclusion

The Copehagenization of Christchurch would bring very significant economic savings to the economy (in the ballpark of $131,000,000 per year, according to my calculations). But, as Copenhagen has proven, we will need to build the cycle infrastructure first, and use this as the 'bait' to encourage commuting by bicycle so that we can reap the economic benefits. One thing that we have already conclusively proven in Christchurch is that poor cycling infrastructure will never persuade our citizens to get on their bikes.

Listen to a discussion of this post with Kathyrn Ryan on Radio New Zealand

Oh, and in only somewhat related news for Christchurch residents:

There is now a website to help children to cope with earthquake-related trauma. It looks like it could be a useful resource.

So the rumour (which I've now heard from six separate sources) is that CERA is going to demolish all houses within 100 metres of the lower half of the Avon River -- and turn it into a giant park.

By my estimation this would affect some 3,000 households, and given the high proportion of families in this area, would displace perhaps 10,000 people. Naturally enough, it's a pretty upsetting rumour if you're one of these people.

Mind you, that's not even to mention the destruction of heritage housing. There are six 100-year-old residences along the river bank just within the immediate vicinity of my house. Multiply that by the length of the river, and you're looking at an unprecedented loss of heritage domestic architecture. It would be akin to the government ordering the wholesale destruction of Ponsonby or Tinakori Road.

I've already had to console one weeping neighbour, and I wish that the blabbermouths who are circulating this rumour would put a cork in their gobs. I don't believe them for a minute. The mass demolition of riverside housing makes no sense from either an engineering or an economic perspective -- as I shall now explain...

What's the Problem With Houses Next to the River?

The problem is liquefaction-prone soils. If you took a cross-section of the ground in Christchurch's eastern suburbs you would see a very thick (on the scale of hundreds of metres) layer of hard gravel. Above this is a comparatively thin layer of soft sandy soil (up to a dozen or so metres). The sandy soil is saturated with water to within a few metres (or even less in some places) of the surface.

Above: A cross-sectional view of ground layers in Christchurch's eastern suburbs.

Along comes our earthquake. The super-thick gravel layer is just fine and dandy -- but the saturated sandy soil is shaken into a quicksand-like substance. So now we have a thin crust of dry sandy soil sitting on top of a layer of liquefied soil. The weight of the crust pressurizes the liquefied soil beneath, which is then ejected through any weak points in the surface. As the liquefied soil is ejected, the original ground layer (and any buildings on it) subside. Similarly, anything buoyant in the liquefied soil (e.g. sewer pipes, manholes, etc.) will float towards the surface.

It goes without saying that the ground does not subside evenly, and so any houses tend to become rather higgledy-piggledy (to use the technical term) in the process. This sounds fairly bad -- but near the river, of course, you have an added bonus. The thin crust of dry soil can slide (on top of the liquefied soil) downhill towards the riverbed. This is the famous "lateral spreading" that produces such photogenic ground fissures. If these fissures occur underneath your house (called "lateral stretching") then they may well break your house into several pieces. Not good, and awfully expensive to fix.

The Grains of Truth in The Rumour

At this point, you may feel inclined to point out that Christchurch has already had the earthquake -- and what, therefore, is the problem with rebuilding? It's not like we're expecting another earthquake, right?

Well, to be perfectly honest, we haven't yet had the big earthquake that we were expecting. That would the Alpine Fault, which has historically gone off every 160 years or so, but which has been nervous-makingly silent for the last 290 years. It could go off tomorrow; or it could be another whole bunch of decades. What we definitely do know is that strain energy has been building up along the fault line. It's rather like inflating a balloon, and wondering when it will go 'pop' -- but on a much larger scale.

The good news is that, in all probability, the effects of the resulting earthquake in Christchurch will be more like the September 2010 event than February 2011. But, as we know, this can still munt a good few houses.

Generally speaking, in areas away from the river, the soil liquefaction from the September quake tended to damage buildings via fairly modest amounts of subsidence. This can be remedied comparatively easily -- particularly in the case of houses with a suspended timber floor (which most of them are).

Above: Typical 'pile' foundations in a old house with a suspended timber floor. 'Packing' (or replacing) piles can remedy the effects of modest amounts of subsidence.

But in areas close to the river there was much greater subsidence during the September quake -- as well as lateral stretching of the foundations due to ground fissuring. This can be far more complicated and expensive to repair. Indeed, in a few cases it may be cheaper to knock down the house and rebuild.

Add into this the cost of repairing roads, sewerage systems, electricity supply, and water for these riverside houses, and -- according to the rumours -- it is cheaper not to spend money on repairing any of these houses. In other words, the way to save money in the next earthquake is to relocate the inhabitants of these houses somewhere else right now (usually rumoured to be the town of Rolleston).

The Cost of Wholesale Demolition

According to my (rough) analysis using the council's 'Rating' database, it would cost the EQC about $175,000 on average to reimburse each riverside homeowner for their land in the event that they're prohibited from rebuilding. For the estimated 3,000 affected homes this comes to a total of $525,000,000.

In contrast, the total proposed land remediation cost in Christchurch from the September earthquake was $140,000,000. Pretty much all the riverbank would have been remediated under this original scheme, which -- even at first glance -- suggests that the cost of land repair for the riverside would be much less than wholesale abandonment.

Furthermore, many of the houses in this area will actually be repairable. Wholesale abandonment would mean that the EQC would also have to pay out its cap of $100,000 on every single house. Not only that, but insurance companies would have to make up the difference when rebuilding new houses elsewhere -- at a average cost to them of around $150,000 per house. So in the 'worst case' scenario of having to abandon a completely undamaged house, the total cost would be around $425,000 (of which $275,000 would be borne by the EQC, and $150,000 by insurance companies).

And if you start to think about the economic cost of disruption on this scale (not to mention the provision of new sewerage, water, schools, and electricity services in Rolleston) then you're looking at a price tag which completely dwarves the cost of remediating the damaged riverside land.

This is, of course, not to say that all riverside land will be economic to repair. Some of it (perhaps, for example, land which has subsided below river level) may have to be abandoned -- but I think we can rule out wholesale abandonment of the riverside on an economic basis.

But Some People Don't Believe That Land Remediation Will Work

There are various techniques for 'improving' soil structure and making it less prone to liquefaction in future earthquakes. The proposed remediation method for the riverbank is to densify the soil using an industrial-strength vibrocompactor (typically a giant drop-weight lifted by a crane) and simultaneously to introduce gravel into the soil to provide additional strength. This would have the effect of forming an 'earth dam' of high-strength soil beside the river -- thus preventing (or at least greatly reducing) lateral spreading.

But there are those who are sceptical of such an approach. In my hearing, one Christchurch resident has even described land remediation as "politically correct". Yes folks, there is now a new benchmark for moronic usage of this phrase.

Such sceptics maintain that the only way to truly safeguard riverside houses is to employ 'deep' foundations -- piles or columns that pass through the surface layers of sandy soil and penetrate into the hard gravel layer. But this, they argue, would be quite uneconomic for individual houses.

I've looked at this claim, and I'm not so sure about the "uneconomic" bit. My own numbers would suggest (on average) around $120,000 per house for a 7.5 metre foundation depth -- which is still considerably less than the $175,000 cost of abandoning the land.

But putting this argument aside, there are other, much cheaper options for making riverside houses 'liquefaction resistant'. One possible solution is to modify the house foundations so that they operate in the manner of a fuse in an electrical circuit, i.e. offering protection to the superstructure of the house in the event of an earthquake, while (at the same time) being designed for rapid and low-cost repair.

The easiest implementation to explain is a retrofitted 'chassis' approach. As we know, whole houses can be transported on trucks. So it's not much of a conceptual leap to imagine a bolt-together steel chassis being retrofitted underneath the suspended timber floor of a house. The chassis would be supported by four small seismic damper bearings -- which, in turn, would each rest upon a large 'sacrificial' concrete foundation block. In the event of a large earthquake, these foundation points could be inexpensively repaired in an analogous manner to 'changing the wheel' on a truck.

Above: Exploded view showing a simple implementation of a chassis-type 'liquefaction resistant' foundation.

Here's how it would work: during a major earthquake the subsidence and/or fissuring may move the sacrificial foundation blocks to such an extent that the chassis becomes non-level -- even to such a degree that it ends up resting directly upon the ground. Nevertheless, the superstructure of the house has been protected by the chassis, and the house can be easily and cheaply 're-piled' by jacking up the chassis to the correct height, pouring additional concrete on top of (or next to) the existing sacrificial foundation blocks, and reinstalling the seismic damper bearings.

My calculations would suggest that this type of system could be retrofitted on a typical house (with a suspended timber floor) for between $40,000 and $60,000 -- a considerable savings on the deep foundation approach, and much less than the $175,000 cost of abandoning the land.

Conclusions

Don't believe the rumours. In my engineer's opinion, it would be quite uneconomic and unnecessary to engage in wholesale demolition of all houses within 100 metres of the lower Avon River. A more probable approach for (most of) the riverbank would be land remediation, and repair or rebuilding of houses. In the event that land remediation is not possible then there are alternative approaches such as 'deep' foundations or 'chassis'-type systems.

The transmission of these rumours is causing unneeded distress to people living beside the river (who are already having difficulties enough). I think it would be a good idea for everyone to collectively take a deep breath, hold fire on the scaremongering, and wait for the outcome of the CERA report on land remediation at the end of the month.

Listen to a discussion of this post with Kathyrn Ryan on Radio New Zealand.

So now we're living at Cook's beach, and -- having just been rendered homeless twice by earthquakes -- we took time to familiarize ourselves with the Civil Defence Warning System here.

It seemed pretty well-organized. There are signs pointing towards official "Tsunami Evacuation Zones", and a siren that goes off for "more than five minutes" in the event that evacuation is required.

And at 2.00 AM this morning that siren did go off. Was this a tsunami warning? I peered out the window and saw the neighbours piling into their car and then drive off. As I watched, several other vehicles tore down the road at high speed.

We woke the children and inserted them into our car, and still the siren was going. Had it now been five minutes? It seemed like a long time; I wished I'd been measuring it.

We decided that it was sensible to follow the signs to the official tsunami evacuation zone -- presumably there would be other people there who could advise us if this was really a genuine emergency.

Oh, but in an amusing twist, following the evacuation signs for a couple of minutes led us in a giant circle and back to the waterfront. How gaily we laughed!

By now I admit that I was rattled. I was in an unfamiliar place, had no idea where I should be going, and there was -- for all I knew -- a giant wave bearing down on us.

I decided that I should drive the few kilometres along the waterfront to the main road and head for the hills -- how ever far away they were. It has to be said that I was not going slowly at this point. We tore through a 30 km/h roadworks zone, and I noticed that the speedometer was reading 160 km/h.

Eventually, after what seemed almost an unendurably long time, we reached high ground. We tried to get the National Programme on the radio, but there was no reception. Luckily there was a cellphone signal and we checked Twitter -- no trending topics on the subject of a giant tsunami at Cook's Beach.

To double-check I phoned Civil Defence in Coromandel. There was no recorded message advising us of disaster, and the woman who eventually answered the phone declared that a tsunami warning was "News to me".

Sitting in pitch darkness with a sobbing nine-week-old baby, we tried to recreate the sequence of events. Presumably the siren had been the volunteer fire brigade, and the neighbours were members of same, and they (and the other speeding cars) were rushing off to put out a fire somewhere. How embarrassing.

And so we went back to our borrowed bach again -- and reflected that a house on the waterfront sounds really great until the sirens go off.

There are, however, a couple of points that I shall be raising with the council:

1. It doesn't seem to me that siren duration is a great way of distinguishing between a fire callout (which non-firefighters would be well-advised to sleep through) and a tsunami alert (at which everyone should take to their heels and make for high ground). How about a different siren pattern for a tsunami alert, guys?

2. Particularly in a holiday area -- with lots of transient visitors -- you might consider better signage to the evacuation zones. I acknowledge that it is hilarious to lead people who are fleeing a tsunami back to the beach, but (as my schoolteachers used to tell me) there is a time and place for humour.

So now we sit here at 4.00 AM -- feeling slightly stupid -- but unable to shut down all the adrenaline coursing through our bodies.

Mind you, on the upside, it was cool to drive at more than five times the legal speed limit.

Postscript: On reflection, David Haywood wishes to emphasize that the portions of this article dealing with excess speed did not actually occur. It was just something that a guy he met in a pub told him had happened to the guy's other mate. And, no officer, David Haywood can't remember the guy's name -- or even, come to think about it, what pub he was in.