Haworth Old Road
The stone culverts are buried and thought to have been created by the same workers who created the dams above Heptonstall (once they were finished, the navvies were looking for more work locally). Farmers and landowners presumably hoping to improve the land by having better drainage had stone lined culverts dug into the fields. Its not always easy to find these culverts (which apparently exist all over the upper Calder Valley) - unless they have collapsed in places the only clue to their existence is the sound of water rushing along them.
Whilst they don;t have a great flow, the opportunities to use them for micro hydro schemes appear good - as long as they remain in fairly good condition. Feeding a pipe up the culverts to a small dam/settling pool will mean a fairly good head is achievable with very little civil works.