. . .or canalside notices, such as this, which would have been inconceivable a few years back but is now considered necessary to explain our cultural norms to recent arrivals.
A recent post from Adam on Briar Rose reminded me that one of the locks in the flight still has working side ponds. At one time most of the locks here had them but all bar one are now disused, so I was looking out for it. I found it at Lock 6.
The side pond is a very useful water conservation device. It sits parallel to the lock at a level halfway between full and empty and is connected via a conventional sluice/paddle arrangement. Going down, one empties the full lock into the side pond until a level is reached when the paddle is closed and the remainder of the lock is emptied as normal. The next boat can then half-fill the lock from the side pond thus reducing the amount of water lost from the top pound by 50%. Perhaps even this simple arrangement is too complicated for today's boaters, which is why most are now out of use and certainly the boat in front of me and the uphill boat I waited for both ignored it.