Dobroyd Mill is found near Jackson Bridge in Holmfirth, a couple of culverts meet under the Mill to form Jackson Bridge Dike.
The two watercourses met a few meters from the outfall. The concrete floor had eroded enough that the water disappeared down through cracks rather than flowing over the end causing a gently circling foam whirlpool.
The left hand branch was mostly stone/brick arch with a low box section in the middle, after around 110m was the infall.
The right hand tunnel (around 95m) was stoopy vaulted concrete followed by a wide stone arch. It split at the infall, one branch coming from an old tailrace tunnel, the other the main infall.
Bobbins of thread littered the stone cascade leading into the culvert, along with other debris thrown from the broken windows of the mill above.