The New River is an artificial waterway in England, opened in 1613 to supply London with fresh drinking water taken from the River Lea and from Chadwell Springs and, originally, Amwell Springs, as well as other springs and wells along its course.
The New River (Wikipedia)
The New River is one of the major features of the Lea Valley, running from New River Head down to Stoke Newington. Its entire 32 km course can be traced on OS Explorer 174 (Epping Forest and Lee Valley). I followed it further, as far as Canonbury, for my project An Explorer.