Foss Dyke
The Foss Dyke is the oldest canal in England that is still in use. It is about 11 miles (18 km) long. It seems to have been built around AD 120 by the Romans.  It connects the River Trent  to the River Witham at Lincoln.  It was improved in 1121,  and in 1671 a  lock was built at Torksey.  There have not been any commercial barges since 1971, but there is a marina at Brayford Pool in the centre of Lincoln.