Tring Summit closure

[koukouvagia]

 

I have never, ever, see the reservoirs look more sorry for themselves at this time of year.

 

 

I share your gloom, Alan. I've never seen the reservoirs so low – and that's going back 25 years.

 

However, those of us marooned in the Cowroast Lagoon now have nothing much to do apart from watching the water level. We've noticed over the past couple of days that the water has come up about an inch. There's been no borehole pumping, but there has been a bit of rain. This may not sound much, but it may mean that the level has stabilized at about 350 mm below the usual mark.

 

If this is the case, then there'll be no need for plan B (a coffer dam) or plan C (piling across the canal)in order to maintain the level of the lagoon.

 

Originally, the plan was to let the summit drop up to 450 mm and keep boats afloat at a higher level on the long term moorings and in the marina by putting in stop planks at New Ground bridge. These turned out to be completely ineffective, but they now may not be needed if the summit level isn't going to drop further.

 

It'll be interesting to see BW's next set of monitoring figures. The big question will be whether less than 30 mls/per week are being lost.

 

Footnote.

 

I have a photo of Cowroast lock taken in 1929. The level of the summit, as seen by the layers of brickwork exposed, is exactly the same as we see now in Leo's photos. A picture of a stoppage in 1901 (or thereabouts) shows boats by the lock with the cabin roofs at the level of the coping stones - i.e. about a foot lower than the level at present. So lack of water on the summit is not a new phenomenon.

[alan_fincher]

Pictures taken yesterday afternoon, Marsworth flight......

 

 

 

 

 

Edited January 29, 2012 by alan_fincher

[nigel carton]

Depressing

[Ray]

What's the purpose of the large "pipe" opening just south of the top gates in your first and second pictures Alan? It appears to be below weir level.

 

At least it is nice to see that there's virtually no rubbish in any of the pounds.

[matty40s]

very.

 

on a side note, BW originally said they were going to allow booked access to the dry dock at the top.

 

Has that been officially stopped now, otherwise, how/where are they going to get the water to fill that lot again.

[LEO]

Pictures taken yesterday afternoon, Marsworth flight......

 

 

Good Pics Alan,

 

It's going to take a lot of water to fill these pounds and those South of Cowroast lock when the time comes.

 

Is Marsworth bottom lock empty? because my chimney cover is in there.

 

Nice bit of 13.5" brickwork on the infilled culvert by the look of it.

 

M.

[alan_fincher]

It's going to take a lot of water to fill these pounds and those South of Cowroast lock when the time comes.

But ccording to Narrow Boat World

 

the feeder reservoirs are not low

 

Mike, so it's apparently not an issue.

 

When I tried to suggest to Tom Crossley that his last article about the summit closure was highly flawed, he basically did the email equivalent of sticking his fingers in his ears and yelling "NAH! NAH! NAH! - I DON'T WANT TO HEAR!"

 

If any of those who have published stuff for him in the past can convince him he is now publishing total nonsense that would be great, but I've now thrown in the towel.

 

In my view it is a great disservice by NBW to continue to peddle a story that is total bo**ocks, just to do a bit more BW bashing.

[koukouvagia]

 

Is Marsworth bottom lock empty? because my chimney cover is in there.

 

 

Yep. Here is is!

 

[Lesd]

We walked all the way up from Dudswell to the Blue Bell cafe today and share the comments about how depressing this all is. The only observations I can add to Alan and Leo's posts is that there is still a single boat moored high and dry on the summit near the cross over bridge. He's upright but going nowhere. Also I was amazed at the amount of tree 'pruning' that is going on along the northern end of the cutting, there are branches down everywhere and the canal is blocked by floating branches for quite a length (not that its going to be blocking anyone passage of course). Lastly just south of the same cross over bridge you can hear water running off the cutting into the canal, it was nice to hear but small beans I suspect.

 

One item for BSP and anyone else stuck in the cowroast section. I was told that BW will be opening the cowroast lock again next Saturday to let anyone out who needs to...I heard this from someone moored on the off side at cow roast so cant be sure its right or not, that said there's no water below cowroast so not sure how BW are going to arrange it ??

 

Les

[bramley]

may I ask, if the ground drys up a little its going to be a nightmare to refill?

[ditchcrawler]

Yep. Here is is!

 

Well you could have pulled it out

[alan_fincher]

One item for BSP and anyone else stuck in the cowroast section. I was told that BW will be opening the cowroast lock again next Saturday to let anyone out who needs to...I heard this from someone moored on the off side at cow roast so cant be sure its right or not, that said there's no water below cowroast so not sure how BW are going to arrange it ??

Yes,

 

BSP is aware, and hopefully I am helping her move her boat, (though the day she has given me is Friday! ).

 

She has pointed out the lack of water in the next pound down, so hopefully if BW are going to encourage people to leave, they will also find enough water to make it possible!....

 

Today's boring picture confirming levels at New Ground bridge.....

 

 

It does appear to be just marginally lower that a few days ago, but only by a very small amount.

Edited January 29, 2012 by alan_fincher

[Guest]

Ignore me - misread Alan's post...

Edited January 29, 2012 by MJG

[RLWP]

 

Soft Southerners. The Perry Barr flight is usually like that!

 

Mind you, there is always a lot of water available to fill it up again

 

Richard

 

I think that would be a challenge even for Tawny Owl

[classicstove]

A previous post asked what is the pipe in the towpath below the top lock

 

The Wendover Arm has a weir which runs down an open channel and into the pound between the lock through what looks like a pipe

 

I have seen water coming over the weir in previous years particuarly as the pound in fed by the outfall of the sewage works futher alond the arm

[Guest]

Charlie does seem to be saying - 'hey up where's all the water gone...'

[alan_fincher]

Charlie does seem to be saying - 'hey up where's all the water gone...'

Well Megan, the Border Collie accompanying him seemed to be more the water dog. There were serious worries if she jumped in we would not easily retrieve her, because of the high sides.

 

I was nervous of both dogs near the maybe near 12 foot fall to the brickwork in some of the emptied locks.

 

Has anyone notice that if BW do a stoppage on a lock for a week they have to erect masses of barriers for our safety, but if they let some drain dry for several weeks the fact that the first thing you hit is the brick bottom now seems less important..........

 

What's the purpose of the large "pipe" opening just south of the top gates in your first and second pictures Alan? It appears to be below weir level.

 

A previous post asked what is the pipe in the towpath below the top lock

 

The Wendover Arm has a weir which runs down an open channel and into the pound between the lock through what looks like a pipe

 

I have seen water coming over the weir in previous years particuarly as the pound in fed by the outfall of the sewage works futher alond the arm

 

I genuinely don't know, but suspect it is part of the conversion of the side-ponds as part of a by-wash route down the locks.....

 

It maybe that water can flow out of this pipe, through the disused side ponds, and back in below.

 

Yes, I know it is much lower than weir level, but if it isn't at the other end, it could still work that way.

 

I can't see why you would want an inlet, (rather than an outlet), just above a lock - seems a good way of putting silt in at just the point you don't want it to be blocking cills and paddle gear.

 

On the other hand I may be talking rubbish, I'll admit!

[Ray]

It doesn't add up.

 

There's no obvious paddle gear to control water flow through the pipe and if it was always open the upper pound level would be about a foot below what I'll call its normal level. Having said that when the outlet below the lock is flowing it does so at a rate that can seriously affect steerage as a boat enters the chamber.

 

At the same time it is quite normal to see water pouring over the bottom gates of lock 42.

 

The thick plottens!

 

The overflow from the Wendover arm drops into the pound above lock 44, two locks above where Alan's picture shows.

[alan_fincher]

It doesn't add up.

 

There's no obvious paddle gear to control water flow through the pipe and if it was always open the upper pound level would be about a foot below what I'll call its normal level.

 

Not if said pipe travels uphill for a while, though surely ?

 

What would determine the level it might reduce the pound to is the highest bit of such pipe, not necessarily the height of an "intake".

 

But I am purely speculating.

 

Should have tried posting Charlie the dog through it, to see where he came out!

[Ray]

Alan

 

I'm still not sure it makes sense because I would have thought that if your idea was fact the water would never flow over the bottom gates with the gusto that it does.

 

I have a very vague recollection of the side ponds on that lock being removed when the lock wall collapsed. I wonder if they put the pipe in then and did as you say with the pipe as an automated overflow. If that's the case I can but presume that the top gates of the lock are left open (or open themselves) and that's what causes the water to weir over the bottom gates before the level in the upper pound gets high enough to flow through the pipe.

[ditchcrawler]

Not if said pipe travels uphill for a while, though surely ?

 

What would determine the level it might reduce the pound to is the highest bit of such pipe, not necessarily the height of an "intake".

 

But I am purely speculating.

 

Should have tried posting Charlie the dog through it, to see where he came out!

Maybe you should tell BW, it may be where the water is going.

[LEO]

What's the purpose of the large "pipe" opening just south of the top gates in your first and second pictures Alan? It appears to be below weir level.

 

At least it is nice to see that there's virtually no rubbish in any of the pounds.

 

I have been pondering this.

 

It may be that it connected at a sluice, the paddle gear long gone. This would allow any water to be drained from this point, up to and including the Summit level into the nearby reservoir rather than wasting it by running it down the flight.

 

Behind the cottage is a steep drop with a feeder to the reservoir.

 

This lock was rebuilt in about 1992/3 by BW employees, using re-inforced concrete and brick facings.

 

Leo.

[Proper Job]

It always looks so sad when the canal in empty.

 

How long can the banks etc be exposed for before there is long term damage to them from drying out?

[alan_fincher]

What's the purpose of the large "pipe" opening just south of the top gates in your first and second pictures Alan? It appears to be below weir level.

 

I've had a look again today.

 

Despite the apparent low level this pipe and similar ones are set into the wall, I'm now confident these are relatively modern pipes put in to provide the new bye-washes around most of the locks in the middle of the flight.

 

I think this exists at all but the top and bottom locks of the flight, and of those, in all but the middle lock, is achieved by running out of the higher pound and into the old disabled side ponds, and then back out of these again below the lock.

 

(The middle lock of the flight differs in that the side ponds have been in-filled, so can't be used in this way, and here I think a much longer underground pipe bypasses the whole lock.

 

When you look at these pipes they are clearly a modern feature, (in fact I'd say in most cases the actual pipe is some kind of plastic). What seems to be the case is that set back from where they draw off from the upper pound, just across the tow-path, is some kind of pit, covered in long lengths of reinforced concrete. I suspect this is some kind of sump, and that it is the height at which the pipe enters this from the upper pound, (rather than the lower level it is set into the lock apron), that determines the level at which water spills through this pipe. (In other words overspilling water initially travels uphill).

 

I assume when water still spills over the top gates, it is just because it is coming down faster than the total capacity of this pipe to try and hold the level lower ?

 

I have been pondering this.

 

It may be that it connected at a sluice, the paddle gear long gone. This would allow any water to be drained from this point, up to and including the Summit level into the nearby reservoir rather than wasting it by running it down the flight.

No it exists at several locks, and you can clearly see a similar modern pipe entering into the old side-ponds where they are used as a bye-wash.

 

I am convinced they are modern, have no paddle gear or pump involved, and in most cases feed straight into those side ponds.

 

As I said above, the middle lock must be different, because the side ponds are gone, in that case I think a pipe simply connects the whole length of the lock, to flow back in again at the bottom.

 

(At the bottom end we are talking about those sometimes heavy flows from the tow-path side, that suddenly push your front end over just when you think you are making a perfect approach into the lock with only one gate open!.....

[BEngo]

I've had a look again today.

 

Despite the apparent low level this pipe and similar ones are set into the wall, I'm now confident these are relatively modern pipes put in to provide the new bye-washes around most of the locks in the middle of the flight.

 

I think this exists at all but the top and bottom locks of the flight, and of those, in all but the middle lock, is achieved by running out of the higher pound and into the old disabled side ponds, and then back out of these again below the lock.

 

(The middle lock of the flight differs in that the side ponds have been in-filled, so can't be used in this way, and here I think a much longer underground pipe bypasses the whole lock.

 

When you look at these pipes they are clearly a modern feature, (in fact I'd say in most cases the actual pipe is some kind of plastic). What seems to be the case is that set back from where they draw off from the upper pound, just across the tow-path, is some kind of pit, covered in long lengths of reinforced concrete. I suspect this is some kind of sump, and that it is the height at which the pipe enters this from the upper pound, (rather than the lower level it is set into the lock apron), that determines the level at which water spills through this pipe. (In other words overspilling water initially travels uphill).

 

I assume when water still spills over the top gates, it is just because it is coming down faster than the total capacity of this pipe to try and hold the level lower ?

 

 

No it exists at several locks, and you can clearly see a similar modern pipe entering into the old side-ponds where they are used as a bye-wash.

 

I am convinced they are modern, have no paddle gear or pump involved, and in most cases feed straight into those side ponds.

 

As I said above, the middle lock must be different, because the side ponds are gone, in that case I think a pipe simply connects the whole length of the lock, to flow back in again at the bottom.

 

(At the bottom end we are talking about those sometimes heavy flows from the tow-path side, that suddenly push your front end over just when you think you are making a perfect approach into the lock with only one gate open!.....

 

 

The big plastic pipe is connected to a weir in a sort of 'box' under the concrete planks. Excess water runs over the weir and off into the side ponds via a smaller plastic pipe, or a bywash pipe at the middle lock. The big pipe is well below the normal water level so that floating cr@p doesn't get drawn into the weir but goes on down to the lock heads where the standard GU Back-of-Paddle weirs are.

 

Neither the GU standard weirs nor the additional 4inch bywashes can cope with major flows- if that happens (a full lock emptied into a pound which is running weir, say) the the water overtops the gates. That is how the Grand Junction was designed to work. I believe the Rochdale is the same.

 

The extra weirs and plastic pipe bywashes were added when the outflow from Tring Sewage works was built in the 80's. This is claimed by Faulkner to produce about 4 locksful a day, so clearly a huge pipe wasn't needed.

 

At the bottom end, in the tail of lock 39, on the side-pond side is the inflow from the reservoirs which makes up for anyone using the Marsworth junction (Red/White Lion) pound as a summit by coming up from Peters Two and down the Aylesbury Arm (or vice versa), which is quite a popular activity for Wyvern hirers and Aylesbury visitors. The outflow can certainly be enough to make an ass of your approach. I always try go in on the side with the extra arch! The paddle can be seen on the cut-side adjacent to the path to the BW car park just above lock 39 and there is an open leat which runs behind the tea rooms for a short way.

 

N