
1) Civil engineering term
Found on
https://www.crosswordclues.com/clue/headworks

Headworks is a civil engineering term for any structure at the head or diversion point of a waterway. It is smaller than a barrage and is used to divert water from a river into a canal or from a large canal into a smaller canal. Historically the phrase `headworks` derives from the traditional approach of diverting water at the start of an irriga.....
Found on
http://en.wikipedia.org/wiki/Headworks

A flow control structure on an irrigation canal.
Found on
http://www.encyclo.co.uk/local/21804
No exact match found.