millrace

Noun

mill race (plural mill races)

1. A fast-running water-filled channel diverted from a river or stream used to drive the millwheel in a watermill.
   • She liked the cold water of the mill-race, and without shame or hesitation would throw off her frock and float like a mermaid, almost invisible, in the watery element.1935, Benedict Read, The Green Child, Capuchin, published 2010, page 36

   Synonyms:

   lade, mill lade, millrun, watergang