Swales with 1% slope (Jack Spirko's latest video)

Did anyone else see this video from Arkansas uploaded just the other day. Jack talks about the swales having a 1% slope. Is this because they are so long and they'll fill up with water quicker with a little slope? Missed that part

A swale on a 1 % slope will allow you to move water further, perhaps to places that are in need of water. It is not necessarily a catch system anymore putting water into the ground.

Mark Shepard does that, a cross between a swale and keyline. It moves the water out of the valley and to the ridges just like keyline but hold and soaks water like a swale. There is a trick to avoid erosion that I don't know. I need to learn it as I want to convert to silvopasture this fall.

There isn't a trick- i.e. nothing is hidden. It will avoid erosion because that is what the system does. It is very simple, but we tend to complicate it. Mark actually has a bunch of planned responses- like little lessons that he will go into based on what he anticipates the cognitive error his questioner has. It is interesting to observe.

The 1% slope is meant to spread the water from the valleys to the ridges. In order to do such a thing you have to start really high up in a valley, and then end up on a ridge at teeny tiny bit down hill from where you started in the valley. Thus the 1%.
It is still a swale.