What is the difference between a "Ridge point dam" a "keypoint dam" and a "contour dam"?

What is the difference between a "Ridge point dam" a "keypoint dam" and a "contour dam"? And when/why would you use one instead of the others? I have heard all of these terms used in various videos, but I cannot find a definition for any of them.

Tom where these the videos you saw?

https://permies.com/t/21884/earthworks/Darren-Doherty-Youtube-Keyline-beach

Seems like the definitions were in there but I have seen so much stuff over the past few years that I have a hard time remembering.

If you can get a hold of a copy of Bill Mollisons Permaculture A designers manual, he defines them all on pages 158 and 159.

"Ridge points are at the top of ridges where swales take water from the valleys to the ridges, Keylines are in the valleys where the slope goes from convex to concave, and contour dams are built on contour where the slope is less then 8%, so more of a pond on flat land."

No, the videos I referenced were (mostly) Geoff Lawton videos. He briefly calls out their names without explaining them. (Understandably to sell the classes. I don't begrudge him a bit for it either.) Others have mentioned them as well.

I have watched the videos you posted, but a long time ago... Prior to forming the question.I too "have seen so much stuff over the past few years that I have a hard time remembering" where I learned what. I'll have to watch them again. Many thanks

OK so those videos did not define the terms... i can figure that the keypoint dam is a dam that captures the water that settles into the keypoint... a ridgepoint dam, is that just a pond on the ridge?

This video gives a good explaination:
https://www.youtube.com/watch?v=T00yBd4jtX0