>On Locks and Quays tonight, Mike Clarke of L&L fame, whom I thought to
>be a bit of an expert, remarked that the Bingley 5-rise Lock Staircase
>was not a good solution to the problem, because every boat that passes
>through uses 5 lockfuls of water.
>
>Now, I am pretty sure that he is just plain wrong here.
No argument here.
The simplest way I've found to think about it is once a staircase
is "set" for a particular direction, subsequent boats take one
lockful of water. Switching from going up to going down is "free";
switching from going down to going up consumes n (n = 5 for Bingley)
locks of water. Calculating the average water consumption means
making assumptions on how many times you change direction. If you
assume worst case (a direction switch each time), then the average
consumption is n / 2 lockfulls per boat.
Nigel Bromley has a great web page on all this:
http://www.caffnib.co.uk/locks.htm
According to him (I didn't check his math) side ponds makes staircase locks
a lot more efficient in terms of water usage.
--Ken
