Thanks Michael,
Fundamentally there is a mis-match in patterning between general contours and Keyline patterns.
Whilst I understand really well the ecological underpinnings to Mark Shepard's work, his application of Keyline is seemingly based on one part his own geometry and another part the obsolete pattern of the 'common' Keyline, which was talked about in the first book on Keyline, 'The Australian Keyline Plan' (1954) and again in a Second Back Row Press version of 'Water for Every Farm' printed in 1981 in which this 'innaccurate idea' was repeated.
from Ken B. Yeomans in 'Water for Every Farm' (1993)
Now that is not to say its not possible to create a 'common keyline' per se, we have developed a methodology for doing so which is outlined in this
post on our Regrarians.org website. What I will say however is that its not possible to maintain the Keyline geometry using the method that P.A. Yeomans put forward in 1954 or my running a 'Keyline' across multiple primary valleys and ridges as people like Mark Shepard appear to recommend.
The Regrarians methodology I've devised can be seen in the following images from the aforementioned web post:
1. Mark Keypoints in respective primary valleys:
2. Mark Keylines in respective primary valleys:
3. Mark guidelines on respective primary ridges:
4. Using the CAD 'Parallel Offset' function move ridge guidelines so that they join the Keylines:
5. Use these new 'common keylines' as guidelines to rows of various forestry systems or row crops:
So that solved that problem!
Now if you are hell bent on running with contours then the swales or plantings that are planted on that contour will have water that is collected stay put. If there is a gradient on that ditch, mound, swale or whatever other obstruction to overland flow there is then if that gradient is directed to the ridge then water will go there. If you run with contours for every row you will not have equidistance between rows and at a larger scale who is going to seriously mark out the contour for every row. That is why Keyline geometry and its patterns is soooooooooo much better.
The simple elegance of Keyline patterning is that once you mark the Keyline (or next highest contour to the Keyline) of the primary valley and the lower contour on a primary ridge you don't have to worry about the any other contours and so you can shift from the plan that you have now to this. Run parallel to the Keyline/Contour in the valley and above the ridge contour marked.
In short I wouldn't suggest you do what you've suggested and go with the Keyline approach...
Thanks and all the best,
Cheers, Darren