Wooden Piling on the GU

[Bullfrog]

We noticed coming north on the GU 2 or 3 locks before Berkamsted, that contractors are driving wooden posts into the canal bed on the off side and then draping them with some kind of fabric screen between each post. This goes on for several hundred yards.

 

What are they up to? Do they then dump dredged material the other side to remake the off banking or what?

 

Does anybody know?

 

regards

 

David

[dor]

It's been done a lot on the Shroppie, mostly on the off-side. The pocketted nylon mesh is put over the stakes, then backfilled with dredging. It is then usually allowed to colonise naturally.

 

It is put forward as a more green form of piling but is, of course, a much cheaper short-term solution to bank erosion.

[Bullfrog]

It's been done a lot on the Shroppie, mostly on the off-side. The pocketted nylon mesh is put over the stakes, then backfilled with dredging. It is then usually allowed to colonise naturally.

 

It is put forward as a more green form of piling but is, of course, a much cheaper short-term solution to bank erosion.

 

Thanks Dor, I sort of worked out that's what it was, hoped someone would confirm my guess work!

 

david

[alan_fincher]

We have witnessed this extensively in recent years - firstly on canals like DOR mentions, but we have also just boated down past the works Bullfrog mentions on the GU.

 

I have to say, I just don't get it, from what we have seen.

 

The stakes driven through the canal bed are no more than a fairly insubstantial softwood, although it may have been treated in some way.

 

The mesh is not particularly substantial, and the back-fill, as DOR says, is little more than dredging mud, with nothing else obviously added to it.

 

The only additional strength (sometimes) is stakes driven to a line further back, to which some of the outer ones are wire tied.

 

It is very hard, (for my simple brain at least), to understand why the stakes will not completely rot away in just a few years. Because nothing substantial is being used in the back-fill, as soon as stakes and mesh keel over, it seems inevitable that it all must just start to wash into the canal, and silt it up.

 

As I don't think you can treat softwoods so they will not eventually rot away, what am I missing, please ?

[dor]

The stakes will be tanalised, which is a pressure treatment with an inhibitor which is supposed to give a 25 year life. Of course that remains to be seen.

[matty40s]

It is a private contractor (BlueBoar - from Rugby) and the initial area was to lanscape the canal bank surrounds of the new Rose Cottage development by bridge 143.

They have been allowed to remove silt from further down (bridges 142 and 141) to fill the 1.5 metre bank area they have created, and had to continue further down with the bank extensions as part of the deal.

However, because of the recent dry weather, they have underestimated the depth of water which is normal in the pound and some of the lowered sections will be underwater and washed out as soon as the normal rains return.

They have not dredged the cut, purely filled butties from the off side leaf silt build up, so no new speedy gonzales opportunities in the area.

 

However, the local herons love it.

 

Oh, and the contractors also cut the tops off some of the tanalised sticks as they wanted everything to be uniformly the same height, and threw them in the cut,

 

I have several on my roof now drying off, and I shall let you know how they burn come the autumn frosts.

[Graham_Robinson]

'Tanalised', CCA pressure treated timber contained Arsenic, not recommended for burning on any sort of fire.

'Tanalith', the latest supposedly more eco friendly treatment contains some nasty toxins too.

CCA treatment has now been banned but unless you know which treatment has been used and its impossible to tell by sight, be warned.

However there must be thousands of CCA treated pallets still in circulation which eventually get chipped and you guessed it, burnt.

Food for thought!

[Natalie Graham]

All sounds like money well spent then.

[Nickhlx]

Does/did the tanalised wood not adversely affect the water life ?

 

Nick

Edited July 24, 2010 by Nickhlx

[Mikeonb4c]

'Tanalised', CCA pressure treated timber contained Arsenic, not recommended for burning on any sort of fire.

'Tanalith', the latest supposedly more eco friendly treatment contains some nasty toxins too.

CCA treatment has now been banned but unless you know which treatment has been used and its impossible to tell by sight, be warned.

However there must be thousands of CCA treated pallets still in circulation which eventually get chipped and you guessed it, burnt.

Food for thought!

 

I'm a complete newbie on here, lurking mainly, and reading up on all I can about narrowboat living in case I ever get the chance (and if it makes sense) to try it out. But here goes.....

 

Even if in theory the wood may produce undesirable smoke/fumes when burning, you would think that as long as it is being burned in a fire that draws properly, then the stuff will go up the chimney (I would imagine that regularly having smoke/fumes of any sort in confined space is bad news, and certainly carbon monoxide produced from incomplete burning would be). So I would have thought the issue for the occupant is that any fire must 'draw' properly.

 

Turning to the stuff that goes up the chimney, well yes its not ideal that it (or any smoke) adds to atmospheric pollution, but as long as its not being done on industrial scale and/or in areas where smoke, fumes etc. may remain confined (winter anticyclonic weather with posh flats nearby comes to mind), then the environmental impact should not be significant. Its gonna get burned anyway and ya gotta stay warm cheaply where possible ha ha!

 

*Happy* to be shot down on the above, as its only thoughts.

 

Mike

[matty40s]

 

 

For those of you who don't know what we're blathering on about.........

 

 

Mike, makes eminent sense to me.

[Bullfrog]

Oh, and the contractors also cut the tops off some of the tanalised sticks as they wanted everything to be uniformly the same height, and threw them in the cut,

 

When I saw them they were carefully stacking these off-cuts on their floating platform. Crossed my mind then that it would make ideal fuel for someone's wood-burner, hadn't thought about the chemical implications.

[matty40s]

When I saw them they were carefully stacking these off-cuts on their floating platform. Crossed my mind then that it would make ideal fuel for someone's wood-burner, hadn't thought about the chemical implications.

 

 

They must have had quite a few roll off then ..

 

(or got told off!!!)

[Nickhlx]

In those last two pictures, my immediate thoughts were that I am glad I don't live in those houses - a slight rise in water level or a breach of the bank, would be disastrous ! I wonder if they are damp to live in normally.

 

Nick

[Timleech]

One reason for this practice is that by keeping dredgings within the canal there is no need for expensive tipping with all the permissions which that entails, especially if the dredgings are deemed to be 'toxic'.

 

I believe the fabric they use is called something which sounds like 'nickerspan' though I have no isea of the correct spelling

 

 

Oh, and please don't burn those treated offcuts anywhere near me!

 

Tim

Edited July 24, 2010 by Timleech

[matty40s]

In those last two pictures, my immediate thoughts were that I am glad I don't live in those houses - a slight rise in water level or a breach of the bank, would be disastrous ! I wonder if they are damp to live in normally.

Nick

The pink house with the heron suffers from a wet cellar along with the lock cottage opposite. The lock cottage garden was dug out this winter and remains under an inch of water , even in the recent dry spell. The new houses in the other picture are well above the canal level (and are unlikely to have basements, however, the fact that they are 10 metres from the West Coast mainline on the other side would probably put me off.

 

Just waiting for the first residents to stick their "Dont moor " signs up.

[alan_fincher]

The pink house with the heron suffers from a wet cellar along with the lock cottage opposite. The lock cottage garden was dug out this winter and remains under an inch of water , even in the recent dry spell. The new houses in the other picture are well above the canal level (and are unlikely to have basements, however, the fact that they are 10 metres from the West Coast mainline on the other side would probably put me off.

 

Just waiting for the first residents to stick their "Dont moor " signs up.

I'm waiting to see if the (probably unofficial) winding hole just south of Topside, (aka "Pink House") disappears as part of this initiative. I don't think residents have ever liked its use, and at one stage a chain was across it. As there seem to be wooden stakes piled nearby, I'd not be surprised if it got in-filled.

 

 

In those last two pictures, my immediate thoughts were that I am glad I don't live in those houses - a slight rise in water level or a breach of the bank, would be disastrous ! I wonder if they are damp to live in normally.

A serious rise in level is not really possible on this part of the GU, as water would just cascade over gates at the next lock, (as it frequently does, in fact).

[matty40s]

I'm waiting to see if the (probably unofficial) winding hole just south of Topside, (aka "Pink House") disappears as part of this initiative. I don't think residents have ever liked its use, and at one stage a chain was across it. As there seem to be wooden stakes piled nearby, I'd not be surprised if it got in-filled

 

it's been dredged and tidied up as part of this project alan, the stakes are the ones being used to hold the netting along a 1/2 mile stretch. However, as far as breaches go, have a look at the northern garden of the lock cottage next time you come past this area and look how it's been excavated out.......breach waiting to happen.

[GUMPY]

I'm waiting to see if the (probably unofficial) winding hole just south of Topside, (aka "Pink House") disappears as part of this initiative. I don't think residents have ever liked its use, and at one stage a chain was across it. As there seem to be wooden stakes piled nearby, I'd not be surprised if it got in-filled.

 

Its bloody shallow even now!

I think that the are either doing that bit last or are not doing it at all as they have done above the lock and below the bridge

It would be nice to have the WH dredged as it took me 40 mins to turn there yesterday.....

 

Julian

At Bulls Bridge off to the Thames tomorrow

[Lesd]

They have not dredged the cut, purely filled butties from the off side leaf silt build up, so no new speedy gonzales opportunities in the area.

 

When we were moored south of the outflow above the bridge a few weeks back BW contacted me to say I would havee to move within ten days as there were about to dredge along the tow path side. Im well away from that area now so now sure what they actually did, are you saying they only removed silt from the far bank ? If so its a pity as those pounds are pretty shallow most of the way along on the tow path side.

Les

[GUMPY]

it's been dredged and tidied up as part of this project alan,

 

You are kidding aren't you There is a bloody great hump in the middle of the canal about 3ft below the surface

Makes turning anything that has any draft almost impossible.

I have to say that with the plant floating all over the cut and a TS that has been moored by the weir for the last few months it was hard work below lock 58.

Edited July 26, 2010 by idleness

[matty40s]

"it's been dredged and tidied up as part of this project alan,"

 

"They have not dredged the cut, purely filled butties from the off side leaf silt build up,"

 

 

Both the above statements are correct, !!!!!!

 

The winding hole is on the off side, they havn't taken anything out of the bit that needs dredging in the middle or towpath side, in fact, the digger was dropping the first two or three scoops of water and mud into the middle of the cut next to the cottages as he tried to get down to the firmer stuff for the new banks.