Keyline design

Keyline design is a landscaping technique of maximizing the beneficial use of the water resources of a tract of land. The "keyline" is a specific topographic feature related to the natural flow of water on the tract. Keyline design is a system of principles and techniques of developing rural and urban landscapes to optimize use of their water resources. Australian farmer and engineer P. A. Yeomans invented and developed Keyline design in his books The Keyline Plan, The Challenge of Landscape, Water For Every Farm, and The City Forest. P. A. Yeomans published the first book on Keyline design in 1954. Yeomans described a system of amplified contour ripping to control rainfall runoff and enable fast flood irrigation of undulating land without the need for terracing it. Keyline designs include irrigation dams equipped with through-the-wall lockpipe systems, gravity feed irrigation, stock water, and yard water. Graded earthen channels may be interlinked to broaden the catchment areas of high dams, conserve the height of water, and transfer rainfall runoff into the most efficient high dam sites. Roads follow both ridge lines and water channels to provide easier movement across the land. The foundation of Yeomans' Keyline design system is the Keyline Scale of Permanence (KSOP), which was the outcome of 15 years of adaptive experimentation on his properties Yobarnie and Nevallan. The Scale identifies the environmental elements of typical farms and orders them according to their degree of permanence as follows: Climate Landshape (topography) Water supply Roads and means of access Trees Structures (edifices) Subdivisional fences Soil Keyline design considers these elements in planning the placement of water storage features, roads, trees, edifices, and fences. On undulating land, keyline design involves identifying ridges, valleys, and natural water courses and designing with them in mind in order to optimize water storage sites. Constructing interconnecting channels may be part of such optimization.