Harringay, Haringey - So Good they Spelt it Twice!
Photos from the New River Tunnel under Hewitt Road
As I posted a few weeks back, on the day before the New River Path was temporarily closed, I met Pawel Szyndak, the project manager of the tunnel clearing operation and asked him if I could get photos of the tunnel at some point. Pawel has been very helpful ad very communicative and sent me pictures a few days ago. I now have clearance from Thames Water to publish Pawel's photos. (I assume the copyright is with him, or perhaps Thames Water). Thank you, in particular to Pawel and also to Thames Water for the permission to publish the photos.
The photos show the extent to which the tunnel had become blocked with sludge. At the Wightman Road end, it looks like fully half of the tunnel was blocked, although the photos suggest that the sludge was only half a meter deep.
I was surprised to see the shape of the tunnel. It looks like it was bored rather like a smaller tube tunnel. Pawel is not sure if this was the original shape or tunnel lining material. I asked him the diameter and he told me that it is 2.4 metres.
Tunnel inlet at the Wightman Road end at the start of the operation (Photo: Pawel Szyndak)
Tunnel inlet at the Seymour Road end at the start of the operation (Photo: Pawel Szyndak)
Depth of sludge (Photo: Pawel Szyndak)
Inside the tunnel under Hewitt Road, after it was cleared (Photo: Pawel Szyndak)
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Replies to This Discussion
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Permalink Reply by Annie McDonald on
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These are incredible photos. So much rubbish, always makes me angry when I see drink cans etc floating around.
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Permalink Reply by LondonN4 on
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The after picture is brilliant. A keyhole at the end of the tunnel. Thanks so much to you and Pawel for sharing.
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Permalink Reply by Dick Harris on
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Splendid pictures.
The great majority of the sludge is simply sediment carried along by the water flow and which is too small to be caught by the screens at the Wightman Road end. I think that is was mostly sucked up through 6 inch tubes by giant sludge gulpers. There is quite a lot of other rubbish that floats along the river (including water weed, cut grass, twigs, wind blown litter and some deliberately dumped items, even the occasional dead animal or bird). The great majority of this stuff is caught by the screens and is routinely fished out automatically by the large apparatus that was installed in 2018. A few small items especially drinks cans do float through between the bars.
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Permalink Reply by Hugh on
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I asked the person I've been emailing at Thames Water if anyone there knows about the construction of the tunnel. Sadly, they hold little information. But she was able to pass on the following, which is interesting.
There are very few record drawings of the tunnel, and those that do exist are quite poor quality copies of the original and hard to read. Construction material isn’t mentioned, but the original tunnel bore is stated as 9ft diameter, and as the internal diameter is 7ft this means the tunnel walls are a substantial 2ft thick.
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It looks as though your informants arithmetic is original. These figures suggest that the walls are one foot thick.
I seem to remember that the original invitation to tender (in the Metropolitan archives) said the bore had to be 9 feet and I had assumed that it was built with bricks. However, when I asked one of the contractor's team last week about the state of the brickwork, he said the walls appeared to be concrete. This could mean that, at some point after the original construction (in the 1880s), a concrete lining was added.
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I'd always assumed the tunnel was brick built. But Pawel's photos make me question that. Tunnelling and concrete know-how was, I think, advanced enough by the mid-1880s for concrete to have been the original material. After Brunel invented the tunnelling shield in 1825, the first use of a circular tunnelling shield was in 1869 when James Greathead built the Tower Subway. He also patented techniques for spraying concrete, though I don't know if that's what we see in our tunnel. Even if it was originally constructed of concrete, it will have no doubt been improved and refurnished many times over the past century and a half.
I've asked if I can get copies of Thames Water's poor quality copies of the original drawings.
The Harringay Park Tunnel spec. document is already on my list for the next time I go to LMA.
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That would be most interesting although it might not tell us what I would really like to know. Probably the river was moved into the new straight cutting from Hampden Road while the great loop around Harringay House remained in service. This would have meant building a temporary new curve which I have shown in blue on the attached overlay map. Work on the tunnel would then have been able to start in the original bed of the river just outside the temporary embankment. I have often wondered how much of a cutting was made into the rising land before tunneling proper began. It seems likely that the job was finished before any houses were built nearby. It can be seen from the map that numbers 219 and 221 Wightman Road were built over the original bed of the river and the same applies to several houses in Beresford Road and some in Allison, Hewitt and Seymour. Some other ladder houses were built over the original bed of the Stonebridge brook which is now in a culvert which passes under the New River on its way down to the river Lea.
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I asked one of the team today and he described the surface of the tunnel as a thick concrete render over bricks. Some flaking was enough to reveal the bricks but that only slight repairs had been necessary. I am not sure what work remains to be done but he said they would finished in a further week. A lot of their equipment has already been removed but the dam is still in place and the tunnel has little water inside.
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