Tring Summit closure

[Bullfrog]

Alan thank you so much for keeping us up to date on all this.

 

What I don't quite understand is that I can count 6 rows of bricks between the the stone -work and the water line on your earliest pictures and only 6 and half now.

 

This doesn't seem to tally with the measurements being quoted.

 

Can someone explain please?

 

I think the level already looked low in the 1st pics.

 

Does this mean the level was already lower than usual before the "experiment" started and before you started taking pics.

 

regards

 

David

[matty40s]

Devils advocate,

and only going on what I know of the area, and different pounds, and how they interact, along with a decent modicum of geology.

 

and I would say that the photo's of Marsworth flight and the reports of the pounds are fairly conclusive.

Areas around locks (whilst the mean water tables are low) will be vulnerable in the below lock sections. Marsworth flight is empty so fast because the water doesn't want to be there.

 

In the area, any full pounds above a lock, would fill the water table in the area around as a matter of course.

 

Therefore the Cowroast marina site,will automatically start to be leeched out by the local water table, and no amount of pumping will win, you are pumping the local rock fields.

The laggoon site needs to be reduced in area.

There needs to be a rubber sheet/mat stoppage system at Marsworth top.

There needs to be a decent pump back system from the pound above lock 49 to above the pound above 47, which could then be used for long term and visitor moorings again( not available as such during the present water inequalities)

[LEO]

OK here's a question for those like Jim and Mike who get to discuss this with BW management.

 

The original proposal, in Jim's very first post on this, was to drop the summit by 300mm, (so a foot in "old money").

 

My pictures clearly show that it is down by more than "4 bricks" now, so at least 300mm or 1 foot.

 

This has been inadvertently achieved by dropping the Cow Roast "lagoon" and marina that 300mm or 1 foot as well.

 

But no boats in either appear to yet be in any great distress, due to the reduced level, (and presumably if just one or two were, they could be moved into one of the deeper bits ?).

 

So why, if 300mm was the objective can it not now all just be maintained as it is, without worrying about the stop planks, please ?

 

Have I missed something ?

 

Like have they now increased the amount by which they want to drop the bit North of New Ground ?

 

Dead serious question.....

 

Has the plan moved, or has it not now kind of already been achieved, without driving piles across the cut at New Ground bridge ?

 

Jim ? Mike ? What is the latest from Mr Whyatt, please ?

 

Alan,

 

The level is dropping steadily, My boat rests on the bottom now.

 

By stopping/reducing through navigation BW can not only check where carefully where the water is being lost but also save water.

 

By sectioning the canal BW can now (I suspect) get a better picture where the water loss is greatest (assuming they effectively block off the Cowroast Lagoon).

 

I suspect management realised that stop planks would not work from the outset but they were worth a try, if only to stop through navigation to make calculations more accurate.

 

It was worth checking out the cheap option of stop planks to see if they worked - a coffer dam will cost in the region of £3000/5000.

 

It may well be that BW are trying to deliver a wake up call to boaters, water is short, be careful with it's use, but deep down (no pun intended) I feel there is no water available.

 

It would be interesting to try to get details of pumping rates Veiola are taking from their borehole at New Mill (water extracted for domestic use).

 

If the water level gets too low in the canal, tree damage to the canal bed will increase as the roots seek out a source of water.

 

I bet the Kingfishers that have used a nest site in the canal bank for 100 or so years are 'peed off' with the levels reducing.

 

It makes sense if there is going to a be a long term stoppage to try to keep a relatively short section full of water, this helps boats (there is a high concentration at this point) on this section.

 

Water lost through leakage at Cowroast lock is minimal.

 

Due to prevailing levels in the Marsworth flight it will take a lot of water to get the canal navigable again - water that BW don't have (consider the amount needed to fill the long pound between Marsworth Lock and the next one up in the flight).

 

It will be interesting to get an update from Jeff Wyatt and perhaps another meeting can be arranged.

 

L.

Edited January 25, 2012 by LEO

[sheriff]

Alan,

 

The level is dropping steadily, My boat rests on the bottom now.

 

By stopping/reducing through navigation BW can not only check where carefully where the water is being lost but also save water.

 

By sectioning the canal BW can now (I suspect) get a better picture where the water loss is greatest (assuming they effectively block off the Cowroast Lagoon).

 

I suspect management realised that stop planks would not work from the outset but they were worth a try, if only to stop through navigation to make calculations more accurate.

 

It was worth checking out the cheap option of stop planks to see if they worked - a coffer dam will cost in the region of £3000/5000.

 

It may well be that BW are trying to deliver a wake up call to boaters, water is short, be careful with it's use, but deep down (no pun intended) I feel there is no water available.

 

It would be interesting to try to get details of pumping rates Veiola are taking from their borehole at New Mill (water extracted for domestic use).

 

If the water level gets too low in the canal, tree damage to the canal bed will increase as the roots seek out a source of water.

 

I bet the Kingfishers that have used a nest site in the canal bank for 100 or so years are 'peed off' with the levels reducing.

 

It makes sense if there is going to a be a long term stoppage to try to keep a relatively short section full of water, this helps boats (there is a high concentration at this point) on this section.

 

Water lost through leakage at Cowroast lock is minimal.

 

Due to prevailing levels in the Marsworth flight it will take a lot of water to get the canal navigable again - water that BW don't have (consider the amount needed to fill the long pound between Marsworth Lock and the next one up in the flight).

 

It will be interesting to get an update from Jeff Wyatt and perhaps another meeting can be arranged.

 

L.

The cost of a coffer dam 'which you quote' is buttons,short change.BW need to hurry up.

A wake up call to boaters...yesterday going across London for example the Bw boat in the distance left every lock wide open....so its not a wake up call,boaters everywhere who leave gates open are just lazy and dont care. BW included...I asked them when I caught up..no answer,shoulders shrugged.

 

3 years ago BW knew there was going to be a problem at Tring and has had plenty of oppurtunity to take action.BW are not the sort of people who have had the long term future of your canal system at heart.

within there walls,the management spent far to much time..in meetings just to have a meetings.theres so much mistrust amongst them...London has a drought situation on its doorstep..I was told yesterday by a BW person....there is a reservoir(brent i think)which is collected rain water..so they will connect pumps to use that..in the near future...buys some time.

 

shut the system down in winter to allow proper maintance and to carry out major improvements.eventually the goverment will have to provide funds,so much money has beed wasted over the years............apart from that...im off for a late breakfast.

[mayalld]

3 years ago BW knew there was going to be a problem at Tring and has had plenty of oppurtunity to take action.

 

And what action should they have taken?

 

If the problem is a dropping water table, there is very little that they can do.

[Ray]

If there's anyone near Marsworth top lock (45), there's a depth indicator part way between the top gate and the nose of the island between the lock and dry dock. A picture of this might give us some clue as to how much lower than usual the water level in the summit is. I can never recall the level being at what I assumed the 0 point on the scale. From memory there are severl "tide" marks already on that gauge.

 

Whilst I accept that the level is low now I'm sure that it isn't much lower than I've known it in the days before the most recent spell of heavy dredging. Was the level ever on weir (recently) and was BW's statement about a 300mm drop actually a drop of that much below the then water level which might actually then put the level at 450mm below weir?

[alan_fincher]

OK,

 

I now accept that BW seem to have changed from "drop by 300mm" to "drop by no more than 450mm".

 

What I'm not clear is whether this is from what it would be if full, or the significantly depleted level it was already at when the planks went in. That makes a big difference to the final answer!

 

To stop me starting another information flow with Whyatt, and confusing the issue, could I ask those already in discussion with BW to clarify.....

 

1) If you are now planning to drop by "no more than 450mm", what level are you treating as the starting point ?

 

2) What do you plan to do when you get to 450mm down, and it is still falling ?

 

3) Given (depending on how you measure it) 450mm down will probably mean boats on the bottom in the "lagoon", when do you actually intend to start work to establish a better "dam" at New Ground.

 

Thanks.

[sheriff]

And what action should they have taken?

 

If the problem is a dropping water table, there is very little that they can do.

informing boaters when posting licences or by e-mail..the need then to ensure locks are closed and not to waste water.

 

its not just about the water table...all leaks amount up over the combined system..and if people over the year,take care to ensure locks are shut behind them..it hepls to lessen the amount of water need to be extracted.

 

im out more than most a good solid ten months of the year and see the waste water, its is a lot.

 

the other two months I just cruise around London...and we have lock gates here which open up after you closed them. so I have to go back and close them up by letting a touch of water out to close them up...also i am not selfish like some and try within reason to share,flights for example...

 

also I wish to see people who are intrested in the canal system run it.

 

the outlook is not good at the moment

[BEngo]

In the area, any full pounds above a lock, would fill the water table in the area around as a matter of course.

 

Therefore the Cowroast marina site,will automatically start to be leeched out by the local water table, and no amount of pumping will win, you are pumping the local rock fields.

The laggoon site needs to be reduced in area.

There needs to be a rubber sheet/mat stoppage system at Marsworth top.

There needs to be a decent pump back system from the pound above lock 49 to above the pound above 47, which could then be used for long term and visitor moorings again( not available as such during the present water inequalities)

 

 

The Cowroast Marina itself I believe is puddled. ISTR there was along argument between BW and the developer (Peter Topping??) many years back about their need to see it watertight before allowing the connection ( and a row about connection charges too). So the marina itself should not be losing water (except that the main line is going down).

 

There is a back-pump system fom Northchurch to the summit. It might need a good clear out, but is there. Why would BW want long-term moorers in the pound above 47, where there is no drinking water and the Sani-Station is at Cowroast, not to mention the complete absence of parking?

 

A lagoon at Cowroast makes sense, as might another one at Bulbourne (dammed off at the Grand Junction Arms bridge) as this could be fed by the sewage works at Tring, although there is now no water or sewage point in this bit. Anywhere else also lacks services and would make BW's job even more difficult.

 

N

Edited January 25, 2012 by BEngo

[koukouvagia]

its not just about the water table...all leaks amount up over the combined system..and if people over the year,take care to ensure locks are shut behind them..it hepls to lessen the amount of water need to be extracted.

 

im out more than most a good solid ten months of the year and see the waste water, its is a lot.

 

 

 

However, there's an extensive backpumping system in use. For example, any water running off the Tring summitcan be regained. Admittedly, there will be an extra cost inelectricity.

Most of the water lost in thehydrological area covered by the Tring reservoirs is lost though thelowered water table and by evaporation, not leaking gates or gatesleft open.

 

 

 

[mayalld]

informing boaters when posting licences or by e-mail..the need then to ensure locks are closed and not to waste water.

 

its not just about the water table...all leaks amount up over the combined system..and if people over the year,take care to ensure locks are shut behind them..it hepls to lessen the amount of water need to be extracted.

 

The problem is that in this particular case, it IS just about the water table.

 

The amount of water leaking through the canal bed due to a low water table is so great that even if no water was wasted at a lock, it would make no difference,

[LEO]

informing boaters when posting licences or by e-mail..the need then to ensure locks are closed and not to waste water.

 

its not just about the water table...all leaks amount up over the combined system..and if people over the year,take care to ensure locks are shut behind them..it hepls to lessen the amount of water need to be extracted.

 

im out more than most a good solid ten months of the year and see the waste water, its is a lot.

 

the other two months I just cruise around London...and we have lock gates here which open up after you closed them. so I have to go back and close them up by letting a touch of water out to close them up...also i am not selfish like some and try within reason to share,flights for example...

 

also I wish to see people who are intrested in the canal system run it.

 

the outlook is not good at the moment

 

It sounds as if you had a good breakfast.

 

The problem here is that we are talking about a summit level (ie top point in a system) fed by Pumps. It's a bit like a high point in a house, the reservoirs being the storage tank. If there is no water to pump up to storage tank and the system leaks, the storage tank will run dry and then the system will dry out too.

 

Leakage through lock gates at either end of the summit is minimal so where is it going?.

 

Shutting the canal in the winter to carry out maintenance - great but where's the money for repairs coming from..BW's money box is empty..it would be easy to go 'Off topic' on this one, but let's keep it focused - how about you start another topic - Where should BW get the extra money to maintain Canals and several thousand listed structures from....

 

Leo.

[alan_fincher]

Alan thank you so much for keeping us up to date on all this.

 

What I don't quite understand is that I can count 6 rows of bricks between the the stone -work and the water line on your earliest pictures and only 6 and half now.

 

This doesn't seem to tally with the measurements being quoted.

 

Can someone explain please?

 

I think the level already looked low in the 1st pics.

 

Does this mean the level was already lower than usual before the "experiment" started and before you started taking pics.

David,

 

I think some of the statements made about the levels simply don't bear scrutiny, based on what I have actually been observing at New Ground Bridge.

 

I think everybody now accepts the planks there are doing nothing, so any measurement taken there represents the level on the whole summit, (anybody want to disagree ?).

 

So if the level at New Ground has not changed between two different days, then I would say neither has the level on the linear moorings or in the BWML marina.

 

The hard bit is "how much was it down by before the planks went in", because, as you know it can in normal operation be at many levels, and the highest "tide line" on brickwork doesn't actually represent what might be called "normal".

 

My take is that when I first took any photos, when they had yet to fit the planks it was about 225mm / 9" / 3 courses of bricks down. Does that sound reasonable ?

 

In which case, I estimate on the following dates, it was down by these amounts, (first number is taking my first photos as a dataum - bracketed number is an assumed overall figure, based on the assumption it was 150mm down in the first place.....

 

Fri 13th Jan - 0mm (225mm) (Planks not fitted)

 

Sun 15th Jan - 40mm (265mm) (Planks fitted - unsheeted)

 

Mon 16th Jan - 60mm (285mm) (Planks fitted - now sheeted)

 

Tue 17th Jan - 40mm (265mm)

 

Fri 20th Jan - 40mm (265mm)

 

Tue 24th Jan - 110mm (335mm)

 

Now my best guess, if they are serious about 425mm, is no more than 90mm more to go. Another 3.5", or a bit over a course of bricks. I'm not sure how many boats would be put on the bottom in a serious way by this, but wonder if by a bit of juggling, they couldn't avoid the "dam" at all. There is a lot of deep water up by the lock not being exploited, or alternatively boats if deeper draughted boats were breasted outside others, they would have more depth to float in.

 

I don't know how close to the bottom the deepest boats in the marina are, though, but as it is pretty flat, is it a major issue if some settle down a bit - they are not going anywhere, are they ?

[koukouvagia]

UPDATE 25th January

 

The 450mm mark has almost been reached. The levels were down probably about 100mm before the restrictions started.

 

BW have recalibrated the losses that were occurring (I think they must have read Alan's figures!) and before the restrictions came on, 76 megalitres not 61mls, were being lost each week from the summit.

 

Since the levels have been allowed to drop, 30 megalitres per week are being saved. (If the savings go on for another month BW will have saved a whole reservoir full of water(Tringford contains 150 mls)

 

The ecologists won't let the levels fall below 500 mm.

 

Plan B is going ahead this week. The lagoon will be topped up, not from the Cowroast borehole (where the amount allowed under the extraction licence needs to be preserved),but from the Northchurch borehole and via back pumping to the lagoon.

 

BW are actively planning to tap some of the water from Weston reservoir by using temporary pumps and pipes. This is a sensitive area, because of the reed beds, but at the moment 14 mls per week of water are lost from this reservoir from overspill. These14 mls will now not go to waste. It's a case of every little helps.

 

Jeff Whyatt will issue an official update later today.

Edited January 25, 2012 by koukouvagia

[LEO]

UPDATE 25th January

 

The 450mm mark has almost been reached. The levels were down probably about 100mm before the restrictions started.

 

BW have recalibrated the losses that were occurring (I think they must have read Alan's figures!) and before the restrictions came on, 76 megalitres not 61mls, were being lost each week from the summit.

 

Since the levels have been allowed to drop, 30 megalitres per week are being saved. (If the savings go on for another month BW will have saved a whole reservoir full of water(Tringford contains 115 mls)

 

The ecologists won't let the levels fall below 500 mm.

 

Plan B is going ahead this week. The lagoon will be topped up, not from the Cowroast borehole (where the amount allowed under the extraction licence needs to be preserved),but from the Northchurch borehole and via back pumping to the lagoon.

 

BW are actively planning to tap some of the water from Weston reservoir by using temporary pumps and pipes. This is a sensitive area, because of the reed beds, but at the moment 14 mls per week of water are lost from this reservoir from overspill. These14 mls will now not go to waste. It's a case of every little helps.

 

Jeff Whyatt will issue an official update later today.

 

Cheers, thanks for the info.

 

M

[sheriff]

The problem is that in this particular case, it IS just about the water table.

 

The amount of water leaking through the canal bed due to a low water table is so great that even if no water was wasted at a lock, it would make no difference,

OK I stand corrected..

[alan_fincher]

Cheers, thanks for the info.

 

M

Yes,

 

Thanks Jim for staying on the case with this.

[debbifiggy]

Cheers, thanks for the info.

 

M

 

Official update just received

 

"Dear all,

 

Firstly , thankyou for all your support over the last 2 weeks, the actions we have taken have certainly made a difference and I want to keep you informed with this below

 

The calculated losses in the week prior to taking action were around 76 ML (megalitres). To put into context Tringford reservoir holds 166 ML when full

 

In the first week (upto Mon 16th Jan ) – the calculated savings were that 20ML of water was conserved. This was only a part week.

 

Last week (upto Mon 23rd Jan ) – the calculated savings were around 30ML

 

The Tring group of reservoirs benefited by a net inflow of 52 ML last week – without the actions taken locally this would have been only 22ML

 

As we stand the Tring reservoir group are holding 47% of their maximum capacity – this time last year it was 63%

 

From a water ‘consumption’ perspective :-

- We avoided drawing any water from the reservoirs

- We utilised Cowroast borehole for 3-4 days, but now need to ease off this and hopefully rest the borehole for extraction later in the year

- Shortly we will start to use Northchurch borehole and run Dudswell & Cowroast pumps to transfer to the point of need

 

We do have issues with making the planks (by New Ground Bridge) watertight. Given measures that have been tried to date it seems that there is leakage around the brickwork rather than the planks themselves. We continue to seek a sustainable way of limiting this situation, so that we can achieve an even lower level across the summit (currently c350mm down).

 

How are the reservoirs ? See below- modest recovery, much much more rainfall is necessary of course

 

Thanks

 

Jeff Whyatt"

 

 

Sorry I couldn't copy the graph across.

D

[koukouvagia]

Official update just received

 

 

 

Sorry I couldn't copy the graph across.

D

 

Here it is:

[Alan de Enfield]

Here it is:

 

The 2011 actual does not appear to have improved over the last couple of weeks (since the actions were taken) compared to the previous weeks.

[jenlyn]

My real concern is that my cruising hs been cut in half. I will be shortly coughing up 800 quid for a license, and then spending all summer avoiding patrol officers. I know I have Thames and lea, but bad weather could put the Thames to rest, and the Olympics have put paid to the lea.

[carlt]

Official update just received

So, presumably, if it rains from now until the start of the tourist season, there will be sufficient water for a few weeks, assuming the canal sides are not leaking even worse, due to them drying out.

 

What happens if we have another dry summer, then autumn and we are back here, in a worse state, next January?

 

Are there any long term plans to seal the canal bed or are we looking at a long term cutting off of the North from the South of the system?

 

This "make do and mend", long term, appears to be a "make do and make worse".

[mayalld]

So, presumably, if it rains from now until the start of the tourist season, there will be sufficient water for a few weeks, assuming the canal sides are not leaking even worse, due to them drying out.

 

What happens if we have another dry summer, then autumn and we are back here, in a worse state, next January?

 

Are there any long term plans to seal the canal bed or are we looking at a long term cutting off of the North from the South of the system?

 

This "make do and mend", long term, appears to be a "make do and make worse".

 

Could a lining solution be developed which would cope when the water table rises.

[sheriff]

My real concern is that my cruising hs been cut in half. I will be shortly coughing up 800 quid for a license, and then spending all summer avoiding patrol officers. I know I have Thames and lea, but bad weather could put the Thames to rest, and the Olympics have put paid to the lea.

same here...back on lee now for two weeks so I dont overstay.

 

catch up with you in a few weeks jenlyn

[carlt]

Could a lining solution be developed which would cope when the water table rises.

Yes quite easily (though not necessarily cheaply).