Logic of restricted lock flight hours to preserve water

[Steve Bassplayer]

I initially thought it was mainly the psychological effect of reducing traffic by putting off those hoping to cruise (inconvenience of limited hours through locks and potential long queues).

 

However, as was pointed out to me, it's the very queuing which helps preserve water, as there is more likelihood of boats sharing the same water going up and down. 

 

On broad canals, queues also increase the chance of sharing locks. 

 

I see there has been a hint that C&RT may consider shutting off entire sections of navigation if water levels get too low. That may also put people off cruising. Nobody wants to get stuck I guess?

 

Anyway, let's all do a rain dance. 🙂

 

 

 

 

 

[IanD]

4 minutes ago, Steve Bassplayer said:

[snip]

 

Anyway, let's all do a rain dance. 🙂

 

 

That's why I know it'll be raining on Saturday... 😞 

 

https://www.facebook.com/Smiffs.W6

Edited July 4 by IanD

[George and Dragon]

I wonder what effect this is having on the hire businesses - would you risk a holiday where you might not be able to go anywhere?

[Wafi]

One thing that puzzled me is that there are restricted hours at Hillmorton but not at Calcutt, even though that's draining the same pound. Not sure whether that's related to the stoppage at Stockton, maintaining access to Calcutt/Ventnor marinas, or for some other reason.

[Woody Too]

I mentioned this in a different thread but on speaking with a CRT guy at Napton he seemed to think it was very likely that, unless we had some serious amounts of rain very soon, full lock closures in that area would be on the cards.  Hopefully its not the case but certainly it's worth bearing in mind if you are planning any trips in that area. 

[Lily Rose]

I have assumed, possibly incorrectly, that it's at least partly due to being easier to have restrictions at locks/flights normally managed by volockies. 

[Steve Bassplayer]

2 minutes ago, Wafi said:

One thing that puzzled me is that there are restricted hours at Hillmorton but not at Calcutt, even though that's draining the same pound. Not sure whether that's related to the stoppage at Stockton, maintaining access to Calcutt/Ventnor marinas, or for some other reason.

 

Someone told me that the reservoir at Calcutt was pretty full and that there is a problem trying to pump water into the canal from there. If that's true  hopefully someone can confirm, then now is a good time to fix the fault maybe? 🙄

[Wafi]

4 minutes ago, Steve Bassplayer said:

Someone told me that the reservoir at Calcutt was pretty full and that there is a problem trying to pump water into the canal from there. If that's true  hopefully someone can confirm, then now is a good time to fix the fault maybe? 🙄

The reservoir does look pretty full. I believe it feeds the pound between Calcutt and Stockton (which is still at normal level) under gravity, but needs pump(s) to get water up to the "mid Oxford" pound. There's a sluice to replenish the reservoir from that pound, so that would make sense. No idea what the status of the pump(s) is though.

 

The bottom lock at Calcutt leaks like a sieve, I reckon half a paddle's worth. Apparently the pound above it has been getting very low overnight; if the pumps aren't serviceable, it must be taking a lot of water out of the top level to refill that pound every morning.

[Steve Bassplayer]

3 minutes ago, Wafi said:

The reservoir does look pretty full. I believe it feeds the pound between Calcutt and Stockton (which is still at normal level) under gravity, but needs pump(s) to get water up to the "mid Oxford" pound. There's a sluice to replenish the reservoir from that pound, so that would make sense. No idea what the status of the pump(s) is though.

 

The bottom lock at Calcutt leaks like a sieve, I reckon half a paddle's worth. Apparently the pound above it has been getting very low overnight; if the pumps aren't serviceable, it must be taking a lot of water out of the top level to refill that pound every morning.

Thanks for that. Actually I think the boater who told me about Calcutt reservoir said it was a defective pump. I wonder whether C&RT are getting it fixed? 

[john6767]

4 minutes ago, Wafi said:

The reservoir does look pretty full. I believe it feeds the pound between Calcutt and Stockton (which is still at normal level) under gravity, but needs pump(s) to get water up to the "mid Oxford" pound. There's a sluice to replenish the reservoir from that pound, so that would make sense. No idea what the status of the pump(s) is though.

 

The bottom lock at Calcutt leaks like a sieve, I reckon half a paddle's worth. Apparently the pound above it has been getting very low overnight; if the pumps aren't serviceable, it must be taking a lot of water out of the top level to refill that pound every morning.

The reservoir at Napton is lower than the pound above Calcutt locks, so needs the pump the feed it directly, or alternatively it feeds into Calcutt marina via a channel through the marina grounds to one of the wet docks, and then to the pound between Calcutt and Stockton.  It then uses the back pumping from the bottom of Calcutt locks to the top to feed the Napton pound.  If the Napton pound is full the water then goes into the spillway to feed Napton reservoir and then goes round the loop again!

 

[David Mack]

1 hour ago, Steve Bassplayer said:

However, as was pointed out to me, it's the very queuing which helps preserve water, as there is more likelihood of boats sharing the same water going up and down. 

It also provides the opportunity for the staff who lock up at the end of the permitted hours to ensure that all gates and paddles are closed, so there is less chance of water being lost overnight through open (or part open) gates and paddles.

[Chris John]

1 hour ago, Woody Too said:

I mentioned this in a different thread but on speaking with a CRT guy at Napton he seemed to think it was very likely that, unless we had some serious amounts of rain very soon, full lock closures in that area would be on the cards.  Hopefully its not the case but certainly it's worth bearing in mind if you are planning any trips in that area. 

A CRT employee or a volunteer lock keeper?

Edited July 4 by Chris John

[hoopdriver]

Well, the Leeds & Liverpool Canal is fully closed all the way between Wigan and Leeds and a close eye is being kept on the rest of the canal to Liverpool. The reservoirs at the summit pound are extremely low. In the latest bulletin CRT said they were preparing for the possibility of fish rescues on the canal. I don’t think anyone up here will be going anywhere for the foreseeable 

[Alan de Enfield]

Hopefully @LadyG had time to get up there before they closed it off.

[Alway Swilby]

Most of the Rochdale is closed along with the Huddersfield Narrow. So along with the Leeds & Liverpool closure it has been impossible to cross the Pennines for quite a few months now.

[Woody Too]

21 hours ago, Chris John said:

A CRT employee or a volunteer lock keeper?

It was CRT employee as far as I know. 

[Steve Bassplayer]

https://canalrivertrust.org.uk/notices/0197d9fd-2888-726c-b46f-2174920c40be

 

Grand Union from Birmingham to Stratford canal closed due to low water.

 

 

[alan_fincher]

On 04/07/2025 at 14:33, Wafi said:

One thing that puzzled me is that there are restricted hours at Hillmorton but not at Calcutt, even though that's draining the same pound. Not sure whether that's related to the stoppage at Stockton, maintaining access to Calcutt/Ventnor marinas, or for some other reason.

 

Many of the "candlestick" locks on the Grand Union Birmingham main line have (often automated) back pumps installed, meaning that water used through lockage gets pumped back above the lock involved.

 

If that were the case at Calcutt it would mean water levels there are to some extent self maintaining, whereas at Hillmorton once it has run down it can't be put back up again.

 

That said my ageing memory can't recall obvious signs of back-pumping at Calcutt, so I am rather doubting that this could be an explanation.

 

Anybody know?

[PaulJ]

17 minutes ago, alan_fincher said:

 

That said my ageing memory can't recall obvious signs of back-pumping at Calcutt, so I am rather doubting that this could be an explanation.

 

Anybody know?

Nope but if it is pumped its a bloody useless one as the second pound down is always empty with the wb in there high and dry 😀

[alias]

24 minutes ago, alan_fincher said:

That said my ageing memory can't recall obvious signs of back-pumping at Calcutt, so I am rather doubting that this could be an explanation.

 

Anybody know?

 

Yes there is, but for the flight rather than each lock. There is a utility building at the bottom with an inlet under a wooden baulk, and an out let at the far end of the top lock landing.  I think someone posted a while back that they have been trying to get it working better as there were problems.

7 minutes ago, PaulJ said:

Nope but if it is pumped its a bloody useless one as the second pound down is always empty with the wb in there high and dry 😀

 

Since they pump from below bottom to above top this will happen if the bottom lock is less watertight than the middle.

[Big Bob W]

On 04/07/2025 at 14:59, Steve Bassplayer said:

Thanks for that. Actually I think the boater who told me about Calcutt reservoir said it was a defective pump. I wonder whether C&RT are getting it fixed? 

We got held up at Calcutt for an hour or so in May whilst they had a diver down inspecting the pump below the bottom lock.

[Wafi]

32 minutes ago, alias said:

Since they pump from below bottom to above top this will happen if the bottom lock is less watertight than the middle.

Which it is. In fact I suspect the bottom lock at Calcutt is less watertight than my boat's colander.

 

Found a page on the CRT Website describing how various different bits of the system get their water. A few tidbits:

• There are pumps at Hillmorton
• The summit pound of the Oxford can be replenished from the Braunston pound via pumps at Napton
• Pumping water up the Watford flight costs £12 per million litres (£1.20 per lockful if I've got my numbers right)

So the Oxford summit can be resupplied by pump, but that obviously depends on sufficient capacity in the pumps, sufficient water in the lower pounds and/or reservoirs, and sufficient funds to pay the electricity bill. Ignoring evaporation and leakage, half the water pumped into the summit pound presumably makes its way back to the Braunston pound, but the other half goes South and ends up in the Cherwell, at which point it's lost from the system.

[Mike Todd]

21 hours ago, Wafi said:

Which it is. In fact I suspect the bottom lock at Calcutt is less watertight than my boat's colander.

 

Found a page on the CRT Website describing how various different bits of the system get their water. A few tidbits:

• There are pumps at Hillmorton
• The summit pound of the Oxford can be replenished from the Braunston pound via pumps at Napton
• Pumping water up the Watford flight costs £12 per million litres (£1.20 per lockful if I've got my numbers right)

So the Oxford summit can be resupplied by pump, but that obviously depends on sufficient capacity in the pumps, sufficient water in the lower pounds and/or reservoirs, and sufficient funds to pay the electricity bill. Ignoring evaporation and leakage, half the water pumped into the summit pound presumably makes its way back to the Braunston pound, but the other half goes South and ends up in the Cherwell, at which point it's lost from the system.

I did hear a figure for the annual cost of back pumping on K&A - alas I have forgotten the detail! - it was said that it makes the K&A the most expensive navigation on the network.