Keyline is an entire and thorough design methodology and process for managing landscapes regeneratively.
Nothing defines the nature of an ecosystem more than its availability of water. Without available water there are deserts, but with an abundance of water, there are rainforests. The former is almost devoid of life while the latter manifests some of the highest levels of biodiversity found within the earth’s biosphere. It is apparent from this that water is fundamental to life, it was this concept that was an influential driving force for the conception of the Keyline-land- planning-system. The keyline concept was first developed by the late P.A. Yeomans of Australia in response to the desertification and increasing erosion observed in the Australian landscape. Percival Alfred Yeomans (1905-1984), or PA as he preferred to be known, was an exemplary deep redesign/design thinker and practitioner.
According to Yeomans, the inseparable trinity of landscape design is its climate, land-shape, and water supply.
This inseparability is realised because of the relationship that exists between the climate and a sites land-shape (topography) which is directly responsible for the amount of water available to any site. These three fields determine a landscapes development and grant the consideration for the remaining five fields- Access, Trees, Structures, Sub-divisional Fences and Soil.
P.A. Yeomans characterised this logical and prioritised process of landscape design as the Keyline-Scale-of-Permanence (KSOP) which serves as the foundation and framework by which the keyline process of landscape planning and decision making is executed.
All Green Curves designs, education and consultancy services follow the adapted Regrarians scale-of -permanence.
Scale of Permanence
Analysing and understanding the biospheric climate which influences a specific area and is therefore ultimately responsible for the formation of the sites existing and changing topography and its ecosystems. As designers, it helps determine and regulate what activities we can do and what possibilities are available.
The human climate, who is involved? who are the decision makers? what resources are available? what are the spheres of influence with respect to what we are doing? These are some of the questions that require answering to form an holistic framework by which a comprehensive intent can be established that will motivate and direct the projects development.
Analysing and understanding the lands shape through the analytical study of aerial, topographical maps in order to bring about physical context to the site.
Water is an essential component for life, water, and therefore rainfall are paramount in determining land development. We have to get the systems for managing water precise to ensure the rest of the design reaches its full potential and is ultimately successful. Design details follow the integrated systems of water management.
Defined as arteries of movement, access synchronizes with water management systems, contour lines, and ridges to improve efficiency of movement, reduce energy consumption and mitigate erosive and damaging impact to surfaces.
Defined by the first four fields, forestry manifests itself in many natural and created forms, synchronizing with water management systems and access, designed as riparian zones, shelterbelts and agroforestry systems.
Following topographical patterns and respecting the existing infrastructure now in place, divisions can be realized as temporary or fixed fencing used in the management of domesticated and/or wild animals. Subdivisions grant us the ability to manage the relationship between animals and landscapes in a way that mimics natural behaviours.
The integrated placement of these structures correlates to the now existing framework, in-place as a result of the five aforementioned fields within the scale-of-permanence. Placement satisfies the need to optimise the potential energy flows.
Healthy soils are the foundation for a healthy functioning biosphere and are therefore a primary objective. Healthy soil requires air, moisture, space, sunlight, and microbiology, getting these conditions correct and we quickly kick-start the regenerative soil building processes.
Integration of ideas and long term vision as a successful regenerative enterprise. Building an attractive narrative to find niche in market place.
Energy is fundamental as a driving force in cyclical and linear systems. Our main objective is to focus on creating systems that exhaust energy potential as it moves from centres of concentration until it disperses and finally reaches entropy.
As the keyline concept was being formulated P.A. Yeomans developed a set of land shape terms that are crucial in the understanding of keyline and instrumental in the methodology of Keyline design.
Keyline designs include, but are not limited to: irrigation dams, diversion channels, integrated water channels, cultivation patterning, and access routes. The correct placement of these depends on an association with corresponding landscape features.
The most important being:
Main ridges - The primary water divide line, responsible for the partitioning of water-catchments. This ridge is the highest on the horizon.
Crests - A convex landform rising in series along the main ridge. These landforms have a descending relationship between the elevations of each successive crest. In-between each crest lies a Saddle .
Saddles - A concave landform located between crests. The starting point for the accumulation of water from rainfall and the beginning of a primary valley.
Primary valleys - A succession of water drainage landforms descending from the starting point of accumulated rainfall on the saddle and eventually draining into stream floodplains.
Primary ridges - A succession of convex landforms, descending from the crests which also find completion at the floodplain or stream.
Keypoints – Located in both the apex of a saddle and the primary valley landforms. Each primary valley has its own keypoint, located along the centre line of the valley floor. It’s position is realised where the slope in the valley floor suddenly starts to steepen, it is a point where natural forces transition from erosive to forces of deposition. Keypoints have a descending nature that corresponds to the descending nature of the main ridge and its crests and saddles.
Keyline - The keyline is a topographical contour line connected to the saddle keypoint in a saddle and the valley keypoint in a valley. Both keylines do not extend beyond the valley landforms, a position identified by a change in the contour line known as the inflection point. The keyline is used to develop the keyline cultivation pattern.
Keyline pattern cultivation- A cultivation pattern that causes water to drift away from the valley centres, out towards the ridge lines. This water is held in the soils where it is allowed to permeate the soil surfaces, culminating in sheet-flow being distributed evenly over undulating landscapes.