This is one of the locks at Dutton, on the River Weaver. The river has been straightened in places, to enable large commercial vessels to sail through to Northwich. Now adays there is no commercial traffic and it is used mainly by canal long boats for pleasure.
While I was there this canal boat turned up, the lock keeper drained the lock and opened the lower gates. This longboat looked tiny in the huge locks as it made it's way upstream. Once safely inside, the gates were closed, the sluices opened and the lock refilled back up to the dark line on the side of the wall. Then the top gates were opened and they continued on their way.
There is an information board there and apparently each time the lock is used, 500,000 gallons of water are used.
