key point / keyline / contours / confusion

Hello all;
This is a topo of a 20 acre property I have recently purchased. I believe I have found two key points in this design. I'm unsure if I should follow the contour lines directly or deviate and use the keyline method which has more evenly spaces swales. Or maybe I'm just confused overall? But, some advice and/or suggestions would be greatly appreciated. I have taken a PDC 6+ years ago but never had any real time experience in the field.

I recommend that you make your swales on the contour lines. You want to hold all the runoff in the swales so that they don't flow off your property. If after a few years you realize that you need even more swale you can always add some more or make the current ones bigger/deeper/etc

Hello and welcome to permies.

These are different methods for different types of cultivating.

With a swale, you can hold more water, but it is recommended for trees, and you have to mulch the swale, and stabilise the terrain with fast seeds and saplings.
It also needs to consider the spill out, this is where the excess water is going to evacuate so it does not ruin the land below. Typically in a cascade of ponds.

With keylines some water may be lost downwards, but the management is very easy. The lines can be plowed with a simple knife tool that breaks just a line where the farmer places the seeds, so the earth is not loosen by the landscaping. Once the seeds grow, their stems and roots will create the barrier that will hold the running water. The disturbance is minimal, the risk of overflow is low, and only one contour line needs to be measured since the other lines are measured against the first line with a simple rule.
Ponds can be used to store surface water in both cases, but they are more useful for swales.

Sorry for the late response. Thank you both for the sound advice.I would like to put some ponds at the key points Where the pink circles are, picture one, But with all the red tape involved I don't think that will be an option, so I'm thinking. Maybe give those swales some fall to move some extra water away from that key area or key point to an area that needs more water. And how are rainfall Comes into the calculation. Our soil type is dolma cobbly loam. And our average rainfall is about 13 inches per year.