The mills captured and harnessed the water.
Once you have listened to the commentary continue your journey.
At the river go through a small gate, turning left on to a riverside footpath. Walk over the footbridge and up the walled lane to the hamlet of Rodmer Clough.
The first building is Rodmer Clough Pottery, where you bear left, then follow the lane straight ahead until you meet a tarmac road. Here take a few metres detour up the concrete road and look to your left, where you will see the second dam for Rodmer Clough Mill (please keep on the track, the mill dam is on private land).
Returning down the concrete road the tarmac road bears round to the right, passing the site of Rodmer Clough Mill on your right. If you look carefully you may see the site of the water wheel pit, but stay on the track (the mill site is on private land and is unsafe). To your left is a lone house set on its own called Salt Pie, which was the site of Edge Mill, another water powered mill fed by two dams hidden in the trees behind it.
Here is a good place to listen to the next commentary.