Tiny lock gates at Haddlesey

[pete.i]

Hi all

The flood gates at Haddersly at the end of the Selby canal have what appears to be smaller gates on the canal side of the main gates. The tops of these gates are just above the water level. As far as I am aware these have not been used at any time recently. There does appear to be a hinge at one end and there are two gates, one each side of the lock entrance. As I say these lock gates (the main ones are really flood gates as opposed to lock gates although they operate in the same way as lock gates. I think you can see the bits that I am asking about in the two piccies.

 

Does anyone know what these gates (?) were used for?

 

Cheers

 

Pete

 

 

Umm hope those pictures work.

[steve hayes]

Look like breach gates

[Theo]

Look like breach gates

 

Which are a more convenient form of stop plank

 

Nick

Edited February 19, 2012 by Theo

[pete.i]

Look like breach gates

 

 

Okay. Can you explain what a breach gate is please. Probably I'm thinking that you mean breech gate and I'm guessing that a breech gate is there in case the main gates get breeched i.e. overcome under flood conditions but I don't know so an explanation of either spelling would be appreciated.

 

To be honest they do seem a little small to be breech gates. I'm not even sure that they are even gates to be honest. There appears to be a hinge at one end and there are two of them., one each side of the canal so, presumably when they are closed. they would meet in the middle.

 

Pete

 

Ah right Thanks Theo. Yes that could be what they are.

 

Still not convinced though. I do admit that I have no idea what they are for so I could be totally wrong and you both could be right. It just does not seem to be a relevant place to have stop gates (planks)

 

Pete

Edited February 19, 2012 by pete.i

[Timleech]

Okay. Can you explain what a breach gate is please. Probably I'm thinking that you mean breech gate and I'm guessing that a breech gate is there in case the main gates get breeched i.e. overcome under flood conditions but I don't know so an explanation of either spelling would be appreciated.

 

To be honest they do seem a little small to be breech gates. I'm not even sure that they are even gates to be honest. There appears to be a hinge at one end and there are two of them., one each side of the canal so, presumably when they are closed. they would meet in the middle.

 

Pete

 

Ah right Thanks Theo. Yes that could be what they are.

 

Still not convinced though. I do admit that I have no idea what they are for so I could be totally wrong and you both could be right. It just does not seem to be a relevant place to have stop gates (planks)

 

Pete

 

http://www.dailywritingtips.com/breach-breech/

 

Edit - not entirely sure what their purpose would be in a place like that. I think the lock has been rebuilt since I was there, but I'm assuming the level upstream of the lock is river & not canal.

 

Gates like that are sometimes used on canals where there is a perceived risk of breaching, to protect embankments for instance.

 

Tim

Edited February 19, 2012 by Timleech

[Guest]

ang on a mo---

 

So we close the breach gates which closes the Selby off from the bottom lock gate, what next?

 

Don't we achieve the same thing by just closing the bottom (Selby canal side) lock gate??

 

 

but I'm assuming the level upstream of the lock is river & not canal.

 

 

Correct...it's the River Aire

[Timleech]

 

 

 

 

Correct...it's the River Aire

 

Just maybe -

 

The weir on the river might be one which needs maintenance from time to time & the river level is dropped for this. These gates would then be closed to keep the water in the canal?

 

Tim

[carlt]

Is the plaque behind them at all informative?

[Guest]

I'm thinking -

 

When the river level is really low...close the 'breach' gates to hold the water in the Selby, empty the lock into the River Aire, open top and bottom gates on the flood lock and the chamber is accessible for maintenance.... including the area around the bottom gate

 

Is the plaque behind them at all informative?

 

Thinking the same too.

Edited February 19, 2012 by MJG

[pete.i]

I'm thinking -

 

When the river level is really low...close the 'breach' gates to hold the water in the Selby, empty the lock into the River Aire, open top and bottom gates on the flood lock and the chamber is accessible for maintenance.... including the area around the bottom gate

 

 

 

Thinking the same too.

 

 

No the plaque is just something that, basically, advertises British Waterways. Says something like "This is Haddlesey lock. British Waterways." or some such thing. Next time I go down I will take a picture of that. The small plaque on the top of the gate(?) also does not say what the gates are for but it does have a date on it. I have been to Haddlesey lock loads of times and today is the first time that I have actually noticed these gates.(?) I think your explanation is probably the closest MJG. If the river level drops then they could be used to stop the Selby Canal emptying into the river Aire or as you say for maintenance. I would have thought the main gates would have done that though unless they get broken for some reason and having to wait for the river to fall to a low level before any maintenance is carried out doesn't seem plausible to me butg I do stress that is said in a questioning way because I reeally don't know.

[ditchcrawler]

No the plaque is just something that, basically, advertises British Waterways. Says something like "This is Haddlesey lock. British Waterways." or some such thing. Next time I go down I will take a picture of that. The small plaque on the top of the gate(?) also does not say what the gates are for but it does have a date on it. I have been to Haddlesey lock loads of times and today is the first time that I have actually noticed these gates.(?) I think your explanation is probably the closest MJG. If the river level drops then they could be used to stop the Selby Canal emptying into the river Aire or as you say for maintenance. I would have thought the main gates would have done that though unless they get broken for some reason and having to wait for the river to fall to a low level before any maintenance is carried out doesn't seem plausible to me butg I do stress that is said in a questioning way because I reeally don't know.

They swing the opposite way to the main lock gates

[Guest]

They swing the opposite way to the main lock gates

 

Which supports the theory that they are there to keep the water in the canal.

[steve hayes]

Which supports the theory that they are there to keep the water in the canal.

 

Agreed

[pete.i]

They swing the opposite way to the main lock gates

 

 

Yes they do so they would be closed against any flow from the canal into the river. So that looks like what they are for.

 

That brings up another question from me though. How on earth do you lower the water level on a river. There is a weir downriver from the lock and another weir upriver at Beale lock. Both of these would require maintenance at some time presumably as would the lock gates at Beale and Haddlesey but how would they lower the river level to do that. I can't see BW waiting for the river to go down naturally so how would they do it?

[steve hayes]

Yes they do so they would be closed against any flow from the canal into the river. So that looks like what they are for.

 

That brings up another question from me though. How on earth do you lower the water level on a river. There is a weir downriver from the lock and another weir upriver at Beale lock. Both of these would require maintenance at some time presumably as would the lock gates at Beale and Haddlesey but how would they lower the river level to do that. I can't see BW waiting for the river to go down naturally so how would they do it?

 

Drought ????

[Pluto]

The weir at Haddlesey and Beal were originally ones that would allow the river level to be lowered so, should there be a problem with the Selby Canal flood gates, the river level could be lowered. If the problem was silt, something which was always a problem on river navigations, the lock could be kept full using these small gates, and the water in the canal then used to flush away any silt or other obstacle from the flood gates. It was much easier than using manual labour to remove silt, etc, and many docks had flushing systems to combat siltage.

[Chertsey]

They swing the opposite way to the main lock gates

Suggesting that they are there for the rare occasions when the usual relative water levels are reversed?

[pete.i]

Drought ????

 

 

LOL no chance we get everybodies rain up here in Yorkshire.

 

Pluto. That sounds plausible. How would they use a weir to lower the levels. I am not suggesting you are wrong but I do not know how they would actually do that.

[Timleech]

LOL no chance we get everybodies rain up here in Yorkshire.

 

Pluto. That sounds plausible. How would they use a weir to lower the levels. I am not suggesting you are wrong but I do not know how they would actually do that.

 

This is the weir, my guess is that the sections between the masonry piers were movable in some way (why else have the piers?), even if they are fixed now.

 

Apparently the old lock beside the weir was used for maintenance boats to access the weir from below even after that section of river navigation fell into disuse.

 

Tim

[Pluto]

This is taken from a notebook written by an A&CN engineer in the mid-twentieth century and shows what they called a turnpike, in effect a rotating board in a sluice that allowed levels or water flow rates to be altered. The name turnpike was also used on the Lee Navigation for their early locks, possibly because the gates turned. The smaller drawing shows the deals on a weir. River weirs were built of stone, though the upper sections were wood so that levels could be lowered or flow rates increased whilst maintaining the upper level. You can see the same thing on by-wash weirs, though in many places the wooden deals have been removed to lower the canal level as a cheaper solution to stopping leaks at water level. On the Greenberfield to Bank Newton pool on the L&LC, they have now lowered the masonry level of the by-wash to lower water levels still further.

 

[Theo]

I think that this would sit more happily in History and Heritage. I will move it now but if there are objections I can always move it back again.

 

Nick

[pete.i]

This is taken from a notebook written by an A&CN engineer in the mid-twentieth century and shows what they called a turnpike, in effect a rotating board in a sluice that allowed levels or water flow rates to be altered. The name turnpike was also used on the Lee Navigation for their early locks, possibly because the gates turned. The smaller drawing shows the deals on a weir. River weirs were built of stone, though the upper sections were wood so that levels could be lowered or flow rates increased whilst maintaining the upper level. You can see the same thing on by-wash weirs, though in many places the wooden deals have been removed to lower the canal level as a cheaper solution to stopping leaks at water level. On the Greenberfield to Bank Newton pool on the L&LC, they have now lowered the masonry level of the by-wash to lower water levels still further.

 

 

Hi

Only just got back to this thread and its kinda disappeared into the depths of the forum but thanks for that Pluto. I suppose that none of these mechanisms exist anywhere now. Certainly the two locks near the end of the Selby canal at Haddlesey are just obstructions more or less under the water. They are, obviously keeping that part of the river from being tidal as it is below the Chapel Haddlesey weir or at least the Chapel Haddlesey weir is. I will have to do some research myself to find out how all this stuff used to work.

 

Pete

Edited February 20, 2012 by pete.i

[magpie patrick]

Hi

Only just got back to this thread and its kinda disappeared into the depths of the forum but thanks for that Pluto. I suppose that none of these mechanisms exist anywhere now. Certainly the two locks near the end of the Selby canal at Haddlesey are just obstructions more or less under the water. They are, obviously keeping that part of the river from being tidal as it is below the Chapel Haddlesey weir or at least the Chapel Haddlesey weir is. I will have to do some research myself to find out how all this stuff used to work.

 

Pete

 

Hi Pete, I can't comment on the specifics here, Pluto is far better placed to do that, but historically river levels were a lot more variable than they are now, they generally had more water in them as there was much less abstraction, but one BIG source of abstraction was mills for power, and dry periods this could pull the level down. Dukes lock, linking the Oxford Canal with the Thames on Dukes Cut, normally rises to the river, and I suspect now nearly always does, but it has gates facing both ways to allow a fall into the river. Firepool Lock in Taunton was the same, as was The Barge Lock where the Droitwich Canal joins the Salwarpe, in both these later instances the gates that allowed a fall TO the river have now been removed, as the weir crests are at such a height that this now never happens

 

 

Firepool Lock before restoration, with the gates to allow locking down into the river still in place

[Pluto]

A few more images, the first showing the weir comes from the same notebook as the turnpikes. Note that even in the mid-20th century, the removable part of the weir allowed for a change in level of 2 feet 6inches, while the sections between the piers could allow the river to drain completely. The Dam Boards were used during flood times, with normal flow variation being controlled by the sluices between the piers. This set up replaced the one indicated on the map below.

 

 

The next two are maps of the area from around 1770, when the Selby Canal was being proposed. Note that Haddlesey Lock was on its own short canal, typical of almost all the locks on the A&CN at the time. The wears on the upper map are probably training groins which would ensure that siltation from the drain was kept to a minimum. Silt was always a problem where two rivers met. The old lock cut is still visible on Google satellite.