The Ashley Bridge – What’s Happening – and what of the Future?

The current situation is that when the Ashley is in flood the bridge is at a high risk from a public safety perspective – 5 to 7 of the peirs may need to be strengthened in the short term.  The piles are embedded only 2-3m on average and only 1-2m in the main channel.

Compare these two photos:

The Cones Road bridge over the Ashley - unknown date. (Te Papa)

Note the difference in the bed levels.  Note also that some repair work appears to have been done on the nearest pier in the recent photo.  The pier causing the biggest problem is the second one from the camera.  Daniel Smith contractors are lined up to start work soon.

Even with strengthening, the bridge will have to be closed on occasions – perhaps up to 10 times per year. There may be weight restrictions in the future – at present, the bridge is just OK for Class 1.

The cost of annual maintenance and a programme of pier strengthening may cost something in the order of $2 million over the next 20 years – which may be all the life that is left in the bridge.

We all know that the bridge isn’t wide enough and that the southern approach has poor visibility.

So how much will a new bridge cost if it were to be built in the next two years or so?  A preliminary guesstimate for a standard-width bridge is $6 million to $10 million – with a bit more if a cycle and pedestrian lane (or lanes) is added – and that has to happen.  If the benefit/cost ratio meets NZ Transport Agency requirements, which is likely, that cost would be 59% subsidised by them.

Watch this space!  I emphasise that all of the above figures are ball-park estimates that were reported to the Council this week.


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6 Responses to “The Ashley Bridge – What’s Happening – and what of the Future?”

  1. David Lowe Says:

    I’m interested in your comment that “all of the above figures are ball-park estimates that were reported to the Council this week”.

    Why was a report only submitted just this week?

    And given the Council has known of the issues for such a long time, why are we only hearing ‘ballpark” estimates?

    Maybe we should sack the highly paid consultants and just get on with the job?

    • David Ayers Says:

      The problem of the scouring only became known recently. All estimates are “ballpark” until actual design work is done.

  2. Marian Brown Says:

    Hi David – a comment from long-term Loburn residents. While accepting the necessity of closing the bridge at times of high river flow, WDC needs to do much better communicating with bridge users. Detour signage is inadequate. Saw your question about advising motorists on the motorway – why not have a sign at the Lineside Rd/Smith St exit so motorists can turn right immediately off Lineside and re-enter the motorway? Further info should be placed at Ashley/Blackett corner and on SH1 at Amberley, Leithfield etc. Many drivers from those areas use the ‘back road’ via Sefton and Ashley to Rangiora but there is no advice of the bridge closure until you reach Sefton. If signs were placed at the Amberley school and at the railroad crossings on the back road, drivers could rejoin SH1 for the journey south. Why not reduce weight limits now on the bridge – logging trucks, tankers etc are only aggravating the problem. Can pedestrians use the bridge during periods of closure? Two car families might be able to place a vehicle at each side and reduce the frustration of the 25min detour.

  3. David Ayers Says:

    Hi Marian. I’ll pass on your comments to the roading staff – you are not the first to make similar ones. As for pedestrians (and cyclists) using the bridge when it is closed to motor vehicles, we have been told that the danger comes not from the weight of vehicles but from the scouring around the piles – so the bridge is still dangerous for pedestrians.
    Regarding a weight limit: that is certainly under consideration.

  4. Julia Arden Says:

    Like anyone who regularly uses the bridge, I want to see a new bridge, which can take the traffic, keep all drivers calm when crossing past logging trucks, and allow cyclists and pedestrians a safe crossing. A new bridge should be in the planning stage NOW. If cost is an issue (which of course it is!), then how about a gold coin toll for cars, and other amounts for trucks? You could have a hopper arrangement like they do on the Thames bridge in the UK, so you just chuck the money out of the window as you drive through.

    Meanwhile a weight limit would be good – prevent more wear and tear at least.

    Driving over the bridge while the pile driver is working is an act of faith!

    Good luck with the election.

    • David Ayers Says:

      Thanks Julia. Yes, I’ve heard that when they hit the pile just as you drive past is an interesting experience! Regarding weight limits, the bridge just meets the condition where one is not needed, although obviously that could change. We are told that the real danger to the bridge is not the downward pressure of heavy vehicles but the risk of a high flow or a tree being brought down in a flood actually causing a pile to collapse.

      As regards a toll, I’m not sure that would be popular! If the cost is in the $9m area, and we get a 59% subsidy from the NZ Transport Agency, I think it is probably affordable for the District. By way of comparison, the Eastern Districts Sewer scheme cost $35m, the new Rangiora water supply will cost $16m and the Dudley Park Pool cost $9m (less the fund-raising).

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