Stupid question about locks

[Windfola]

So I am having this conversation with a close friend about locks. She is having a problem with the idea that upper pounds (see how good I am getting with terminology!) don't run out of water when the locks are emptied, and how on earth the low lying bits of England aren't flooded by gravity.

 

I have pondered this weighty issue and assuming no pumps are involved, nor thousands of pixies armed with buckets, is it the rain that acts as the big tap in the sky to fill the higher levels?

 

Please tell me, is this the answer? Or am I missing the point entirely?

Edited May 14, 2011 by Windfola

[Guest]

So I am having this conversation with a close friend about locks. She is having a problem with the idea that upper pounds (see how good I am getting with terminology!) don't run out of water when the locks are emptied, and how on earth the low lying bits of England aren't flooded by gravity.

 

I have pondered this weighty issue and assuming no pumps are involved, nor thousands of pixies armed with buckets, is the rain that acts as the big tap in the sky to fill the higher levels?

 

Please tell me, is this the answer? Or am I missing the point entirely?

 

If I am understanding the question correctly -

 

The three main methods of keeping the pounds topped up are -

 

Natural flows from river or natural lakes

 

Man made flow from man made reservoirs

 

Back pumping of water back 'up the hill'

 

There may be others that I am not aware of.

 

This is exactly why the Leeds and Liverpool got into difficulty last year basically the water supply in the higher 'summit' pounds couldn't keep up with the demand produced when the locks are filled and emptied.

 

ETA - and of course the very leaky gates on the L&L don't help either.

 

As to flooding - well of course in times of flood the lower lying parts of the UK do get flooded - not generally by canals od course - normally rivers

Edited May 14, 2011 by MJG

[hmallett]

The upper pounds do run out of water. Hopefully there's enough water in the upper pound that you don't run out though.

The lower pounds usually discharge excess water into rivers or other watercourses.

For keeping the summit pounds full, there's usually one or more reservoirs.

[Guest]

To the OP -

 

If you are interested in how it all works not just the filling of the pounds this little book is a good buy. I've lost my copy otherwise you could have had it.

 

http://shop.ebay.co.uk/i.html?_kw=English&_kw=Canals&_kw=Explained

[Tim]

And in many cases the summit pound acts as it's own resevoir.

[carlt]

The upper pounds being emptied, by boats locking down, are refilled by an equal number of boats locking up.

[saltysplash]

The upper pounds being emptied, by boats locking down, are refilled by an equal number of boats locking up.

 

 

Naughty

[Tim]

I guess the problem is with boat numbers being unequal!

[Guest]

Naughty

 

Carl's post reminded me of the gongoozler last time we were out who asked-

 

"Why don't you just open the gates at both ends at the same time and go straight through"

 

It was a genuine question...

 

 

 

clarity edit

 

I guess the problem is with boat numbers being unequal!

 

Not unless more boats go up than down...

Edited May 14, 2011 by MJG

[john6767]

Carl's post reminded me of the gongoozler last time we were out who asked-

 

"Why don't you just open the gates at both ends at the same time and go straight through"

 

It was a genuine question...

 

 

 

clarity edit

 

 

 

Not unless more boats go up than down...

 

We had a similar question; "what are the locks for, the water looks so flat".

 

 

 

 

[RLWP]

So I am having this conversation with a close friend about locks. She is having a problem with the idea that upper pounds (see how good I am getting with terminology!) don't run out of water when the locks are emptied, and how on earth the low lying bits of England aren't flooded by gravity.

 

I have pondered this weighty issue and assuming no pumps are involved, nor thousands of pixies armed with buckets, is it the rain that acts as the big tap in the sky to fill the higher levels?

 

Please tell me, is this the answer? Or am I missing the point entirely?

 

Just now, most of the BCN is being filled up by pumps! With Chasewater reservoir closed (which is what usually tops the canal up) it is the mine drainage pumps* that are providing water

 

Richard

 

*They are mine pumps, aren't they?

[Chagall]

Just now, most of the BCN is being filled up by pumps! With Chasewater reservoir closed (which is what usually tops the canal up) it is the mine drainage pumps* that are providing water

 

Richard

 

*They are mine pumps, aren't they?

 

Nope, they're his!

[RLWP]

Nope, they're his!

 

I don't wish to know that, kindly leave the stage

 

Richard

[Chagall]

I don't wish to know that, kindly leave the stage

 

Richard

 

and leave applause? ...never!

[magpie patrick]

Just now, most of the BCN is being filled up by pumps! With Chasewater reservoir closed (which is what usually tops the canal up) it is the mine drainage pumps* that are providing water

 

Richard

 

*They are mine pumps, aren't they?

 

It isn't the bad news BW would have you believe, ever since the mines closed, the water table around Walsall, Rushall etc has been rising, and the local authorities have been begging BW to pump more. BW declined, because they couldn't handle more water without a series of Llangollen style bypass weirs at Wolverhampton locks, which the local authorities wouldn't pay for.

[TimD]

I guess the problem is with boat numbers being unequal!

 

You could minimise the water loss when locking up by opening the gate paddles fully to fill your boat with the water, then when you're out of the lock you can syphon in out again

[mayalld]

You could minimise the water loss when locking up by opening the gate paddles fully to fill your boat with the water, then when you're out of the lock you can syphon in out again

 

Even nortier than Carl.

[cotswoldsman]

The upper pounds being emptied, by boats locking down, are refilled by an equal number of boats locking up.

 

But say on Tring Summit all the locks go down, I guess they must pump the water back up.

 

Edited to say: Silly me there are reservoirs close so guess the water comes from these.

Edited May 15, 2011 by cotswoldsman

[RLWP]

<snip>

 

Edited to say: Silly me there are reservoirs close

 

<snip>

 

What an amazing coincidence

 

Richard

 

[cotswoldsman]

What an amazing coincidence

 

Richard

 

 

Now now Richard

[Boatless]

Why they ever gave up having the Archimedes Screws running in the bye washes to move water back up stream I'll never know .

[RLWP]

Why they ever gave up having the Archimedes Screws running in the bye washes to move water back up stream I'll never know .

 

To paraphrase the great philosopher Homer* "On this forum, we obey the laws of thermodynamics!"

 

Richard

 

*Homer Simpson

Edited May 15, 2011 by RLWP

[carlt]

But say on Tring Summit all the locks go down, I guess they must pump the water back up.

 

No the boats locking up to the summit carry the water back up.

 

Would you like to invest in my perpetual motion machine, btw?

[Chertsey]

No the boats locking up to the summit carry the water back up.

 

Would you like to invest in my perpetual motion machine, btw?

Well when the northern end of the Shroppie was low the other week, I did hear someone say in all seriousness that it was the fault of all the working boats going to Ellesmere Port and none coming the other way.

[GeoffS]

Carl's post reminded me of the gongoozler last time we were out who asked-

 

"Why don't you just open the gates at both ends at the same time and go straight through"

 

It was a genuine question...

 

 

And me of the one who asked me how I was going to lower the water enough to get under Pitstone swing bridge!