Help with my Keyline! Trying to determine my keypoints and keylines on my farmland (goat farm)

Hello! I am looking at implementing keyline design on my fields. I will upload a map of the contour lines and water flow on the land. It's a goat farm with permanent pasture on field 16 and rotating temporary grassland and cereal crops on fields 27 and 28. These fields have the main problems areas and have been experiencing issues with waterlogging in the South East corners on fields 16 and 27, 28 and also the South West corner on field 28.  
Id like to change my tilling in line with keyline design to help distribute water flow and prevent erosion... currently i till up and downslope. There are ditches along the border between field 16 and 27 and 27 and 28. My idea is to do keyline tillage and perhaps keyline subsoiling to help more even distribution of water. With climate change the precipitation is becoming much more erratic....

I'm struggling a fair bit to determine the best keylines for tillage and subsoiling and cropping.

Thanks so much in advance!

Heres another useful image of water flow

Welcome to permies!

Heres another useful image of water flow

That's an interesting image - where do you get that from?

I'm not experienced in keylines, and suspect if you just started ploughing across the slope rather than up/down you will see some benefit. As I understand it the keyline ploughing is to plough slightly down hill, but towards the high spots so the water stays in the soil longer and spreads rather than going straight to the lowest spots.
I have had a go at annotating your simple contour plan - red dotted is the high spots, blue/green is the natural valleys/low spots and orange is my suggested ploughing directions. Hopefully someone who has studies this more will confirm whether that makes sense!

Plowing on contour would help a lot even without paying attention to the keyline.

b wrote:currently i till up and downslope. There are ditches along the border between field 16 and 27 and 27 and 28. My idea is to do keyline tillage and perhaps keyline subsoiling to help more even distribution of water. With climate change the precipitation is becoming much more erratic....

I'm struggling a fair bit to determine the best keylines for tillage and subsoiling and cropping.

Thanks so much in advance!

Welcome to permies!

*steps onto soap box* Since tilling destroys soil structure and reduces organic matter content, it will increase runoff, thus the waterlogging along the lower areas of tilled fields especially. Every 1% OM content boosts water holding capacity of soil by about 0.47 gallons per square foot...wowzas. So conversely, destroying OM reduces that water holding capacity. So bonus points to you if you can adopt a gentler cultivation practice to alleviate runoff to begin with! *steps off soap box*.  

Good thinking to work the contour instead of up and down slope!

Regarding keyline, I like Nancy's drawing. I drew one up myself, and I think I'd have a similar recommendation as hers. Imagine my lines are all parallel and equidistant.

I would choose the contour running through those northern notchy-crotches at the boundary between fields 16 and 27 and 27 and 28.

Disclaimer Note: I haven't read Water for every farm, so this is just based on the knowledge I do have from my PDC and personal studies leading up to that. (My teachers left much to desire regarding keyline during the PDCs, to my chagrin.) It appears to my untrained eye that the inflection point between increasingly steep and shallowing contours happens up in those crotchy-notches. Using those as a starting contour "keyline" seems to draw water downhill to the ridges from valleys when the pattern is applied downhill along the presumed primary valley (green dash with the stars). Best wishes!