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In the pathway: Designing your site

Keyline design

Hydrological design at the landscape scale, based on the lines of the relief.

Watch the videoLe Keyline design pour les nulsFabian Feraux, Hydrologie régénérative

Explanation

An approach developed by the Australian engineer Percival Alfred Yeomans in the 1950s (foundational book: The Keyline Plan, 1954), which uses the topography (valleys, ridges, key points) to organise plantings, access and soil work. It maximises water retention, reduces erosion and improves fertility over large areas.

Refined definition

The keyline is the inflection point of a valley where the slope changes abruptly (from steep to gentle). A horizontal “keyline” crossing the valley at this point becomes the reference for organising the whole landscape: parallel offset ploughing (“keyline plowing”), a chain of ponds to store water, plantings on curves. The aim is to capture water as high as possible and distribute it slowly toward the ridges (instead of letting it flow down into the valleys and be lost).

Key points

  • The three-element rule

    1. KEYLINE: the valley's inflection line, a topographical reference. 2. KEYPOINT: the precise point where the slope tips over (often at the top of the valley). 3. KEYLINE PATTERN: ploughing or planting parallel to the keyline, slightly deviated toward the ridges to spread the water. Sources: P.A. Yeomans, The Keyline Plan (1954), Water for Every Farm (1965); Darren Doherty (Australian Keyline System); Mark Shepard (Restoration Agriculture, 2013).

  • Scale of application

    Keyline is designed for large properties (10+ ha), hilly terrain, in semi-arid to temperate climates. On small urban gardens: not directly applicable, but the principle (capture water as high as possible) inspires swales and infiltration channels. For permaculture farms: an excellent method where the relief allows it.

Watch out for

  • • It requires a prior topographical survey (levels, contours), not a beginner's tool on a small flat plot.
  • • Risk: a poorly traced keyline can concentrate water in the wrong place and accelerate erosion. Have it validated by an experienced practitioner.

Sources

  • Yeomans, P.A. (1954). The Keyline Plan. Sydney : P.A. Yeomans.
  • Yeomans, P.A. (1965). Water for Every Farm. Sydney : Murray.
  • Shepard, M. (2013). Restoration Agriculture: Real-World Permaculture for Farmers. Austin : Acres U.S.A.