shallowest lock?

[matrix]

just wondering

I can find lots of details on the deepest locks on the system

but can find nothing about the shallowest ( smallest water level change )

on the GU near us the fenny Stratford lock has a drop of 11 inches

is there any less???

[fuzzyduck]

can we count flood locks?

 

When i was first bringing Fuzzy home in 05 pillings was closed, and set against us. we opened both sets of gates, pootled through, then closed em again. (drop = 0 inches)

[Moley]

Autherley stop lock, 6 inches.

[magpie patrick]

This has often taxed me in moments when I really haven't got enough to worry about: for one, how do you define it? Deepest lock is easy: it's a lock with a big fall and there aren't really any cheats (Although some have either been merged or affected by subsidence so "deepest historic lock" is more difficult. As a general rule I don't accept locks with no gates on and I don't accept ones with gates open at both ends. I've been through Pillings with a fall of one inch and had to work it like a proper lock.

 

Then do we count stop locks? they weren't intended to change level but to control water flow and generally had a notional fall to do this: Autherley, Preston Brook and Hawkesbury are all 6 inches or so, as were several others at one time so do they count? Perhaps not?

 

Fenny Stratford was to allow the Milton Keynes level to be dropped to solve a leakage problem: it's about a foot but I won't argue with 11 inches. Hanham lock on the River Avon near bristol must be about the same, although no official figure is given. Rotherham Lock apparently has a rise of 5 inches (I've never seen it) although as the SSYN rejoins the river Don here it perhaps falls into the "water control" category. County Lock on the river Kennet appears to be less than a foot although last time I saw it the needle weir alongside was in danger of collapse and then the fall would be nowt.

 

And, if the current proposals for the Cotswold Canals are pursued then we will have the worlds first "level lock" that actually needs to be operated! To cross the river Frome at Brimscombe the current proposal is for a lock with "top gates" at both ends and sluices for the river. When a boat wishes to proceed, the river is closed off and diverted into a culvert. the lock is the filled and the gates at both ends opened. The boat sails through, closes the gates and drains the lock: one full lock operation, rise and fall zero.

 

What other shallow locks are their around the place? I'd be happy to put a list together if people want to chip in with their offerings. Perhaps two lists, those still in use and those no longer in use, either coz the canal has closed or they were so pathetic the gates have been taken off...

[Liam]

Dutton Stop Lock on the Trent & Mersey. I think officially it's supposed to be 6 inches but it seems alot less.

[Timleech]

Dutton Stop Lock on the Trent & Mersey. I think officially it's supposed to be 6 inches but it seems alot less.

 

It varies between nothing and six inches, depending on wind, rain, phase of the moon, etc etc.

 

Tim

[BigRoj]

Beeston lock from the Trent to the Beeston canal varies from bugger all to a foot. In fact there's generally one paddle open on both sets of gates, as requested by BW, so there is a steady flow of 'fresh' water into the Beeston/Nottingham canal.

[Hairy-Neil]

What other shallow locks are their around the place?

 

Graham Palmer Lock on the Montgomery?

 

Hall Green has two, one operational, one disused. Marston also has a disused one.

 

What about Warwick Bar lock? For years it was disused, (or did it just not have the balance beams?) then perhaps 5 years ago it was restored, but is it ever used? I suspect it is only ever as stop planks....

 

I've been through Teddington Lock when there was a reverse fall.....

 

Torksey Lock more pairs of gates than you could shake a stick at. It has the capability of working in either direction, but not IIRC at any state of the tide....

[John Orentas]

Stop locks were built for a specific purpose, when new canals were built the owners (there were always owners) of the existing canals insisted on the new canal being at a higher level simply in order than any loss of water from one waterway to another would always be in favour of the old navigation.

 

There were in the early days many more stop locks than exist now, a couple of examples are on the Macclesfield at the junction with the Upper Peak Forest and on the lower Peak Forest at the junction with the Ashton.. It is always easy to see which waterway pre-dated the other, having now just one owner since nationalisation the original need for stop locks has largely disappeared.

 

Very shallow working locks were rare in the early days, the builder would endeavour to make the heights on any given canal as uniform as possible otherwise water wastage may occur, the few that there are now are often a result of some form of subsidence, Big Lock on the T&M comes to mind as result of salt extraction and one on the Rochdale at Miles Platting, coal mining at Bradford Colliery, of course at one lock sinks another must be lifted to compensate.

[magpie patrick]

Stop locks were built for a specific purpose, when new canals were built the owners (there were always owners) of the existing canals insisted on the new canal being at a higher level simply in order than any loss of water from one waterway to another would always be in favour of the old navigation.

 

There were in the early days many more stop locks than exist now, a couple of examples are on the Macclesfield at the junction with the Upper Peak Forest and on the lower Peak Forest at the junction with the Ashton.. It is always easy to see which waterway pre-dated the other, having now just one owner since nationalisation the original need for stop locks has largely disappeared.

 

Very shallow working locks were rare in the early days, the builder would endeavour to make the heights on any given canal as uniform as possible otherwise water wastage may occur, the few that there are now are often a result of some form of subsidence, Big Lock on the T&M comes to mind as result of salt extraction and one on the Rochdale at Miles Platting, coal mining at Bradford Colliery, of course at one lock sinks another must be lifted to compensate.

 

Hi John, I beg to differ on two counts:

 

Shallow locks were common in early days, as were deep ones, but very few mucked about with locks as shallow as a foot. It was later that standardised falls came in, presumably learning from experience. Many of the deepest historic locks (as opposed to later modifications) are among the earlier ones on the system.

 

Second, big lock has not had it's fall changed as a result of subsidence, although it has suffered from it and had to be rebuilt. It's always been around five feet deep.

 

I agree on stop locks, which is partly why I'd leave them out of a list of the shallowest locks.

 

By the way, as a variant, i'd put forward the long gone dudgrove double lock on the Thames and Severn as the most unbalanced staircase pair: upper chamber 9 feet, lower chamber 2 feet 6 inches!

[Adam]

Beal lock on the River Aire is only about 3 inches in the summer. It says in the Nicholson something stupid like 8ftBeal lock on the River Aire is only about 3 inches in the summer. It says in the Nicholson something stupid like 8ft

[fender]

By the way, as a variant, i'd put forward the long gone dudgrove double lock on the Thames and Severn as the most unbalanced staircase pair: upper chamber 9 feet, lower chamber 2 feet 6 inches!

 

and what about Thames Lock on the Wey navigation? Its even less than Dudgrove!

 

Thames Lock wouldnt be described as a staircase but thats essentialy what it is!

 

Wasnt the lower chamber at Dudgrove added as an after thought when it was found the level wouldnt match Inglesham?

[hmallett]

Graham Palmer Lock on the Montgomery?

That's a comparatively massive 18 inches!

[Stroudwater Boy]

and what about Thames Lock on the Wey navigation? Its even less than Dudgrove!

 

Thames Lock wouldnt be described as a staircase but thats essentialy what it is!

 

Wasnt the lower chamber at Dudgrove added as an after thought when it was found the level wouldnt match Inglesham?

Nearly, according to Household it was due to the junction with the river being moved.

 

My vote for the shallowest lock is Kings Norton.

[magpie patrick]

Kings Norton doesn't count, as it has gates open at both ends: there must be half a dozen on the system like that

 

However, Stroudwater Boy, I suspect your own whitminster lock may be a contender when it reopens, I seem to recall that deep is not a term one would use to describe it? 3 inches? 6 inches?

 

Droitwich Barge Lock is likely to be in the running too: the one that connects the barge canal to the Salwarpe in Droitwich itself

[Stroudwater Boy]

Kings Norton doesn't count, as it has gates open at both ends: there must be half a dozen on the system like that

 

However, Stroudwater Boy, I suspect your own whitminster lock may be a contender when it reopens, I seem to recall that deep is not a term one would use to describe it? 3 inches? 6 inches?

 

Droitwich Barge Lock is likely to be in the running too: the one that connects the barge canal to the Salwarpe in Droitwich itself

Ah but the gates are still there, or at least last time I was there. Whitminster will be one of the interesting ones it will depend on rainfall, sometimes the water is level at the weir alongside the lock at other times a torrent, like all canals connected to rivers I suppose. The canal G&S also goes up and down a fair bit according to how thirsty the people of Bristol are and if the pumps are all working.

[Keeping Up]

How about the lock between the Oxford canal and the Thames at Dukes Cut?