Welcome to the Midnight Collective Broadsheet 139
Actively
supporting NZ’s endangered wetland birds
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| A Rushed Job -M2PP under construction June 2016 |
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| Wharemauku Bridge under construction June 2016 |
Local media are reporting signs of
deterioration in the recently opened M2PP expressway here in Kapiti, in the
stretch between our town centre (Paraparaumu) and the Waikanae River bridge.
These include tarmac cracking, discolouration and apparent sinking. These
reports the NZTA have acknowledged, but played down, limiting the damage to the
road surface with carefully weighted understatement as … ‘discolouration and
changes to texture’.
They are monitoring the situation which,
they emphasize, does not pose a
risk to motorists, despite the fact they have been unable to pinpoint the cause. However the further
statement ‘It is too early to determine a timeframe for remedial work’ appears
to indicate that there are genuine engineering concerns they have yet to get to
the bottom of.
What might they be? In the lack of any
details coming out, here is our assessment.
We took a trip through the affected area
and did indeed find signs of deterioration which the NZTA had marked out. We
could photograph the general area but, putting safety first, it proved too
dangerous to stop and get some close ups. However here are the results of the
drive.
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| Joining Expressway from Kapiti Road heading north. |
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| Marked surface heading south from Waikanae. |
This surface marking is probably inconsequential (a paint spill?), but just beyond
this area a long series of cracks have appeared in the centre of the left lane, and these do look problematic.
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| Approaching Kapiti Road exit. |
Here we are preparing to leave the
expressway at the Kapiti Road exit heading south. Just before this area the
NZTA have marked a series of what seem to be small sinkholes that have appeared
in the left lane. These are similar to potholes that have opened up in the
accompanying cycleway, some of which have been marked by the NZTA in a similar
way viz a viz...
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| Marked pothole Raumati Beach cycleway |
So what might the trouble be?
These cycleway potholes have appeared
after sealing and are obviously the result of sinkage in the path, after
construction. The pathways and the expressway itself, were constructed from sand quarried from the
sides of the expressway and the sinkage a result of settling after completion.
Presumably there are ‘best practice’ rules that determine how long they should
be left to settle, but with the rush to get the expressway open before the
election –have they been followed? And is this also the problem with the issues
affecting the expressway itself.
At the Board of Inquiry it was stated
that the expressway would need to be left to settle for six months before it
could be sealed, then opened. Has this direction been followed?
Another contributing cause may be the
after-effects of the Kaikoura earthquake which shook up this area and resulted
in liquefaction in wetland areas. This hasn’t, to our knowledge, been reported
in the media. We are still seeing a lot of dirty brown water in these wetlands,
a characteristic of liquefaction (rain usually turns the drains here black not
brown, while the dune lake before construction began, was always clear). So
what were the effects on the expressway itself of a severe two minute shake
which delayed the opening for three months. The only news we have heard is that
the bitumen plant was affected; not the expressway itself.
Sand is a very useful medium to use to
build roadways – it’s cheap, local and easy to fabricate; but it is erodible, and in this project
has been piled over pakihi (coastal swamp), which has caused subsidence in
other roads put through this area in the past. There are signs also of the
sides of the expressway beginning to be eroded by water draining off the
expressway. Here are photographs of some of this erosion in Raumati Beach.
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| Sand erosion M2PP E-way, Raumati Beach |
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| Ditto |
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| Repeato... |
If this is happening to the ramped sides,
then what is going on inside the constructed roadway and below it?
Track we were listening to while posting
this? Well, this request goes out to the NZTA’s design engineers, with Lesley Gore
hitting her doleful girly best, It's My Party...
It's my party, and I'll cry if I want to
Cry if I want to, cry if I want to
You would cry too if it happened to you
This is a melody John Lennon then picked up
and morphed into the male version, though the original goes all the way back to the
18th Century and Robby Burns’ Mary Morison
I sigh’d and
said among them a’,
‘Ye are na
Mary Morison
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