sluiceway

An artificial channel, especially one for carrying off excess water.

An artificial passage or channel into which water is let by a sluice; hence, any small artificial channel for running water.

The opening in a splash-dam through which logs pass.

An artificial channel into which water is let by a sluice; specifically, a trough constructed over the bed of a stream, so that logs, lumber, or rubbish can be floated down to some convenient place of delivery.

A man-made channel designed to redirect excess water.