This is sort of a report on how I am attempting to solve a problem by building "Drainage Swales" rather than my previous project of building "Retention Swales" to keep water on a slope. I have a different objective in that this is about designing and building Drainage Swales to deliver more water to my pond. I perceive that a drainage swaleshould be different from a retention swale. The retention swale needs a sizable berm and a sizeable trench to hold a lot of water but the drainage does not need large berm or trench as it is moving the water to another place and does not try to hold it.
The First image shows the field immediately above the pond.
This year I had a different project in mind. The land level in the second image has two equal feet on the ends so that it can "step over" irregularities in the surface and one end is placed at the starting elevation and the other end is moved around until the level in the middle has the bubble centered, and a stake is placed at each end so that every feet I get another stake at the same elevation. This is needed if you want to mark out a swale that neither runs up or down hill and a series of these will keep water on a slope long enough to soak in.
But as I want the water to drain I do not want to mark out level lines but rather lines that run on an incline and that leads to the third image.
I never met anyone that I could not learn something from