Keyline Design
P.A. Yeomans developed keyline design in 1950s Australia, facing drought conditions that destroyed conventional farms. He discovered that water flow on contoured land follows predictable geometric patterns, and small manipulation of these patterns can passively distribute water across an entire landscape.
The “keypoint” is where a primary valley changes from convex to concave slope — the inflection point. A contour line through the keypoint (the keyline) guides placement of everything else: swales, farm roads, tree lines, irrigation channels.
Water naturally spreads perpendicular to slope when slowed. Keyline swales — shallow ditches on contour — catch runoff and spread it across the landscape rather than letting it concentrate and erode. The swale doesn’t dam water; it slows and disperses it.
Whole farms designed around one surveyed line, rather than fighting natural hydrology. The keyline determines where trees go, where pastures go, where roads go. Everything follows from one geometric relationship with the land.
Yeomans turned erosive runoff into slow soil infiltration. His farms green up while neighbors’ farms brown out. No pumps, no complex infrastructure. Just understanding where water wants to go and working with that tendency.
Systems thinking in any domain benefits from identifying the keypoint — the single leverage point where small intervention cascades through the whole system. In organizations, it might be hiring criteria (shapes culture for years). In codebases, it’s architectural decisions (constrains all future features).
Find the keyline, design around it.
Go Deeper
Books
- Water for Every Farm by P.A. Yeomans (updated by Ken Yeomans) — The essential text on keyline. Required reading for permaculture students.
- The Keyline Plan by P.A. Yeomans (1954) — The original, now harder to find.
- The Challenge of Landscape by P.A. Yeomans — Extension of keyline thinking.
- Permaculture: A Designers’ Manual by Bill Mollison — Incorporates keyline principles.
Practice
- Keyline.com.au — The Yeomans family’s ongoing work, including the Yeomans Plow designed for keyline cultivation.
- Darren Doherty’s Regrarians platform continues keyline teaching and application.
Related: [[edge-effect]], [[zone-5]], [[legibility]]