The South Forty-Foot Drain, also known as the Black Sluice Navigation, is the main channel for the land-drainage of the Black Sluice Level in the Lincolnshire Fens. It lies in eastern England between
The South Forty-Foot Drain at Pointon, between Boston and Guthrum Gowt. Here its origin as a drainage channel is very evident.
The Holland Fen pumping station, which pumps water from Clay Dike into the South Forty-Foot Drain
Black Sluice pumping station at Boston, where the Drain meets The Haven, was decommissioned in 2018.
The new lock at Black Sluice, allowing navigation from The Haven to the Drain