Part of Redbank Communities
On-site Heritage Centre

76 Arthur Phillip Drive
North Richmond 2754

02 4760 1400

Register your interest

Part of Redbank Communities
On-site Heritage Centre

76 Arthur Phillip Drive
North Richmond 2754

02 4760 1400

Keyline Explained

The Keyline System

Keyline is an agricultural system that utilises the natural topography of the land to capture, store and direct rainwater, efficiently improving the condition of the soil.

Developed by P.A Yeomans in the 1950’s, and later championed by his sons Ken and Alan, it has proven to be a simple and cost effective method to reduce or eliminate the need for chemicals, mechanical pumping or irrigation, and it reliably creates sustainably fertile soil.



+WATCH
An Interview with P.A. Yeomans sons Ken & Allan on the Keyline method

The Keyline method optimises the distribution of water across an entire property. It slows down the movement of water from higher elevations, which will typically end up drier, and inhibits it from running down into low lying lands and off the property.

By using the valleys, slopes and climate, farmers can determine the logical position of on-farm dams, irrigation areas, roads, fences and farm buildings. It also helps to determines the location of tree belts to provide shade and give wind protection.

An aerial photography showing the placement of all 16 keyline dams and contours on site. Source – Water for Every Farm

The objective of the Keyline method is to capture and hold water on a property for as long as possible by controlling when and where it flows using channels, dams, and other natural or constructed features within the landscape.

Plate 13 from P.A. Yeomans' book 'Water For Every Farm' released in 1974

The Keyline system takes its name from a particular contour that runs through a valley at a particular point. The contour is called the Keyline and the point is called the Keypoint. The Keypoint can be found in the steepest part of the valley just below the inflection point where the concave valley meets the convex ridge.

The Keyline contour will hug the curves and natural shape of the valley. It runs through and remains at the same elevation as the keypoint. This is the pivotal contour by which farmers can plow in a parallel manner both up and down the slope.

The Bunyip level – Invented by P.A. Yeomans and used to mark the exact location of the keyline within the landscape

Keyline utilises dams connected by swales and channels to store water. Dams at Keyline height take advantage of gravity to irrigate the land below. Dams higher in the landscape gain greater gravitational advantage to irrigate more of a property but are costly to construct, dams below cost less but require pumps.

25” irrigation valve partly open — capable of delivering 3.7 million litres of water per hour.
P.A. Yeomans on site showcasing the keyline irrigation system.
A partially buried irrigation valve being tested in its flow of water from the dam above.

Global Impact

The Keyline System is sighted as a precursor to modern day permaculture. It has been widely adopted by farm owners globally and is included within sustainable agriculture college and university courses. P.A. Yeomans won the Prince Philip Design Award Australia in 1974 for the design of the Bunyip Slipper Imp with shakaerator, which can to cultivate the ground and leave top soil practically undisturbed. His ploughs are now sold all over the world.

P.A. Yeomans accepting the Prince Philip Design Award in 1974