Comment by Lindsey Berthoud on October 16, 2012 at 12:27

Fascinating! All that historic sludge. 

Pete and I were up the Enfield bits of the New River at the weekend - the water has been drained right down from from about Turkey Street to where it goes into a pipe. More cleaning out ahead of the big anniversary next year?

Comment by Administrator on October 20, 2012 at 10:20

Week 4 - over half way!

The work of clearing out the sludge from the tunnel is now over half finished, and they are fast revising the estimated tonnage.  Originally they thought it would be around 400 tons. That seemed a lot. But they have already taken out 1,500 tons, and the silt is still rising. This photo shows some of the larger items found at the Myddleton Road end.  The small boat and the large barrel must have stories behind them - but we shall never know.

 

The dam now works well, and most of the remaining water is pumped back upstream, only a trickle gets through now.

 

 

You can see the inside of the tunnel for the first time for 150 years. Sorry for the bad focus - better next week.  Again the point of light you can just see is the other end.

 

The Site Foreman says, "The tunnel is in a very good state of repair so far with only minor pointing repairs needed. Quite astonishing considering the age of the tunnel."

They have only found one actually loose brick so far, and that was just at an angle and had not dropped out. The original spec' for the brickwork was:

The bricks to be provided by the Contractor and shall be of the standard size, the quality to be of the first class hard burnt grey stocks (except for such work as may be hereafter specially mentioned) to be sound and free from lime and pebbles and to be of the best manufacture, and if any are delivered of an inferior quality they will be rejected at the expence of the Contractor and no bats less than half bricks will be allowed and these only in limited quantity and no perforated or hollow or other patent brick will be allowed to be used.

At the southern end near Ally Pally they have gone past a section of tunnel where they found a concrete inner sleeve. This is likely to be the steel and concrete lining that was inserted in April 1931 to strengthen it when they made the tube extension from Finsbury Park to Cockfosters. 

 

The photo below shows some of the men who are doing the dirty work. Steve Best, the Foreman, writes, "I would like to send thanks from the gangs working in the tunnel, the cakes and biscuits that have been brought have been lovely!" 

Please do keep them coming!

Comment by Stephen Middleton on October 20, 2012 at 16:32

Please it coming - really enjoying this feed. FYI New River Walk tomorrow: http://www.harringayonline.com/events/new-river-walk-this-sunday-21...

Comment by Richard McKeever on October 28, 2012 at 15:53

New River Tunnel inspection week 5

Caroline Simpson writes:

Foreman, Steve Best has sent me some lovely photos of some of the fish that were rescued from the tunnel area when it was drained down.

“The first is an example of the smaller Roach, Perch and Bream saved. We pulled netful after netful of these out of the tunnel.

Thousands of individual fish. The last is of one of the large Pike saved. The Pike were mainly found at the Station Rd end and there were around six of this size and many more smaller ones. Station road also produced some large Bream and Perch.”

It is great to know that the river is so healthy and that there are lots of fish. Many people who walk along the New River will have seen huge pike resting motionless and silent, looking like statues on the bottom of the shallow areas when the water is clear.

I have not been allowed in to the tunnel itself, but Steve has also sent…..

“As promised here are a few pics showing the level of silt and debris found in the
tunnel. The first shows the level just inside the tunnel under the footbridge at Myddleton, and the second is at the same place looking out just after clearing a small area to establish the volume expected. The last is the level of silt at 300m inside the tunnel from Myddleton Rd.”
Thank you, Steve.

The two teams are working hard to finish the clearing of the tunnel silt before the bats want to come back into the warm. The suction pipes to clear the 1km tunnel were having to be made longer and longer, but maybe those Victorian Engineers had thought of that.

Finsbury Gardens is about half way along the length of the tunnel and there is an inspection shaft with a manhole cover in the gardens. So this week they have started to suck the silt that the men are shoveling in the tunnel into pipes let down the manhole which take it across the gardens and away. This will speed things up, and should only take three or four days work and then the tunnel will be clear.

They have promised to clear up any mess that this makes in the Gardens.

I have said that the tunnel was a ‘cut-and-cover’ construction, and most of it was. But I have looked again at one of the Thames Water archive documents about the construction and found that a short section was indeed tunneled.

“From the end of the New Cut to Wood Green a Tunnel is to be made by the Contractor 1108 yards in length the average depth from the surface to the invert being about 20 ft. The greater portion may be executed in open cutting properly strutted but that portion passing under Nightingale Lane must be tunnelled and as much further as may be required by the Engineer must be executed by tunnelling in short lengths.”

Once the tunnel silt is cleaned out, and any small patches of brickwork re-pointed, the debris will be cleared from the tunnel mouth. They hope that will all happen next week, and then the dam can be removed and the river run again and the fish can go where they like, and the bats can roost in the tunnel and all will be well, we hope, for another 150 years.

Thank you to Barhale and the whole team.

Any celebratory cakes and buns will be gratefully received and eagerly eaten.
Caroline Simpson, October 26th

Comment by Stephen Middleton on October 28, 2012 at 19:54

More great interesting stuff, thanks.

Comment by Lesley Ramm on October 28, 2012 at 21:14

These posts are so interesting. Great work from Caroline Nd the team doing the hard graft.

Comment by Mat Riches on October 30, 2012 at 10:28

Carlsberg don't do blogs but if they did it would probably be the best blog in the world.

Absolutely fascinating stuff! Although after seeing that pike, I'm not swimming in the New River again!

Comment by Lindsey Berthoud on November 1, 2012 at 10:39

Agreed! Love the photos. I never guessed that a sludge clearing exercise could be so fascinating. 

Comment by Administrator on November 9, 2012 at 13:04

New River Tunnel Inspection Week 6-7 -

final update by Caroline Simpson

The work is finished, the lorries have gone, the long pipes are out of the tunnel and away, the clearing team is now working ‘back in the yard’ until the next big job starts.

I have learnt that the New River is what is classified as ‘a flowing reservoir’, but I am sure we will all continue to call it, and think of it, as a River, our River – albeit a man-made creation, canalised and even ‘tunnelised’ in parts.

The final tally of stuff from the tunnel?
Silt total 1,740 tons. Every ounce and pound shifted by hand. And over the 154 years we also have: the two guns and two rounds of ‘live’ ammo’, lots of knives, five or six safes, lots of handbags and credit cards, two motor-bikes, three bicycles, a skateboard, lots of kids trikes and scooters, some imitation Swedish medallions(!) a 17th century pipe, two small Buddhas, lots of plastic dolls, one antique white ceramic doll’s head, a boat, a big oak barrel and the old metal bridge handrail which must have fallen off many years ago. The largest non-silt collection was bottles of various ages.

I am now the temporary custodian for a little collection of the most interesting bottles which should be displayed as a permanent, history-based artwork somewhere local. Ideas and offers of help please.

The fish tally of those moved into safe water was: six or eight large pike, around 20 mid-range and hundreds of smaller pike, tons of other smaller fish took three days to ‘decant’. There were big perch, two big bream but no carp. Steve had previously found a big carp downstream near Hornsey mosque. There were also lots of foreign crawfish who were not rescued and amazingly no-one came to ask for a bucketful for supper.

Dragging out sections of around 400 m of heavy pipe was no joke for the team at this end.

This shows a view down the tunnel with men’s head lamps coming towards us

The photograph below shows the team pulling out a pipe

These pipes were craned up to the top and carted off. The huge crane parked on the future Community Gym land was a one-off sight, as was a little digger on the brick bed of the river and then being hoisted up.

Site Foreman, Steve, has kindly sent us some detailed photos of a few of specific interior details of the tunnel.

One shows the crossing of the large pipe under Finsbury Gardens where the brickwork junction is seamless and superb.

  The other, smaller, pipe is probably a later insertion, to judge from the less classy concrete junction.

It is very special to look up into the manhole which we will only be able to see from the top in Finsbury Gardens in the foreseeable future! It can again become a comfy bat-roost.

And the bats are back! One photo shows an early arrival tucked up where the 1930’s reline (featured last week) meets the brickwork and a bat is still roosting.

The last shows the new brickwork added during the relining. In the crown of the tunnel only

The people
We know nothing about the men who originally built the tunnel, but we are lucky to have a few details about those who have been ‘guests of Myddleton Road’ for the last seven weeks.

The Site Foreman, Steve Best, has worked for Thames Water most of his life and its sister company, Barhale, for nine years on the Tunnel Inspection team.

He has done lots of jobs on the New River: concrete re-lining at Cheshunt, North of the A10, Broxbourne, Anwell (which Steve says is really lovely with two islands and worth a visit), lots of tunnels and raising of embankments to stop leaks.

At Mardensbrook there are four tunnels and there used to be fine sandstone head wall, but sadly the sandstone stocks were so broken that had to be repaired and covered in concrete.

Steve has three children, aged 13, 10 and 6, and, I am delighted to say, took two days holiday in half term to be with the family

 

Photo of the clearing team
This team work very well together and Steve is trying to keep them together for other projects. There are a number of Lithuanians and Romanians as well as ‘Native Brits’, much in the same way as in the 19th century many of the ‘manual workers’ were Irish, but the Irish don’t like working in tunnels these days! The youngest member of the team is Matthew Wilkinson who has just finished his ‘confined space training’. He ‘commutes’ each week from just north of Cardiff – with his Dad David! They are one of a number of fathers-and-sons on the larger team, and there are also two brothers who are Steve’s ‘top chaps’. I don’t know why I was surprised to learn of the related workers, but I was. There feels something ‘good’ about this for me. Barhale itself is a family firm so perhaps there is an ethos, or something.

On the final day, as some men were dismantling the dam, Steve said, “The job has given me some headaches, but it has been an interesting one. Barhale says ‘Thanks’ to local residents, who have been very kind and not difficult or critical, which is what often happens.” He also says, “The blog made it go well, as it was not negative and created an interest.”(Thanks, Steve.)

Well….. I didn’t know ‘till I was well in to this that I was writing ‘a blog’. To me, I have written short illustrated reports. But I don’t mind so long as they have been interesting to readers. I have enjoyed it.

Thank you to Steve Best and all his team and good luck with the next job.

 

---

Sorry…. The bad news is…...the New River Path from Myddleton to Whittington will still be CLOSED for a few weeks more as Thames Water now has to do urgent bank repairs. The banks often get bad in the winter, and after the rains of this year the banks are already slipping and some of the timber shuttering is collapsing. Thames Water is going to keep the path closed until the work is finished and the path safe for us all to use again.

We all hope that work can move ahead quickly and that our path will be open again soon.

But be warned! The timber embankment is in a generally poor state and now has a fairly limited life. It will then have to be replaced in concrete. So make the best of the simpler, gentler, old-fashioned technology and enjoy it while it lasts and look after and respect the New River and all who work in her.

Photo of timber

Caroline Simpson November 7th 2012

 

 

Comment by Kari Koonin on November 9, 2012 at 15:48

Fascinating insights, thanks so much Caroline!

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