Geograph - photograph every grid square

A disused lock that bypassed Howley Weir on the River Mersey in Warrington. Made redundant by the opening of the Manchester Ship Canal, the lock is normally empty except at high tide (20 miles inland), revealing unusual rotary paddle gear. This picture was taken on one of the rare occasions when high spring tides top the weir and the lock. The bridge, now secured for safety, leads to an island ("Monkey Island") formed between the weir and the lock.