Staircase Locks Etruria.

Today we turned on to the Caldon Canal, or to give it its correct title the Caldon branch of the Trent and Mersey canal.  Before setting off up the canal we took the opportunity to top up with water, opposite the stature of James Brindley builder of the canal.

Just round the corner you meet your first obstacle, the staircase locks.  Staircase locks are where two or more locks are built so that you move from one directly into the other.  Where there is a piece of canal between locks (a pound), no matter how short the series of locks are a flight not a staircase.

This staircase is only two locks.  The blip is looking from the gates of the bottom lock towards a boat leaving the top lock.  The two locks together raise the boat 5.8 m (19 ft 3 in).  Staircase locks are a little more complicated than a single lock.  On this staircase, no matter if you are going up or down, you start with the top lock full and the bottom empty.

Going up you motor into the empty lock and let the water down from the top lock to raise you to be able to move into the top lock.  Exactly the reverse going down.  One interesting point in this shot is the top chamber is much larger than the bottom chamber.  So where does the excess water go?  You can see it pouring over the outflow channel to the left of the chamber, under the footbridge.