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   Pattern and Flood-flo are the names which were bestowed on the two original Keyline irrigation procedures. They suit forest and farm.

   In the first attempts to use for irrigating the water which was in such a hurry to get off our farm, costs, in time and money, won easily. Not looking to irrigate a potato patch or a few acres of grass, it had to pay for growing beef; so all the water available was needed and it had to be stored in dams first. There were no difficulties building them; that was already an experience in mining work.

   At that time government departments showed little interest in farm dams for irrigation. Critics described our dams as huge and useless. They said our soil was no good for anything but why cover with water the little good soil we had in the (primary) valleys in order to irrigate worthless shale ridges? Only creek and river flats were worth irrigating!

   Such opinions were universal then, but passengers flying southwards of Sydney today will see evidence of the reversal of this view in the concentration of these dams so close to the metropolis. All were constructed years after we established their practicability and they are for irrigating land formerly believed unsuitable for the purpose.

   We used both flood and spray systems of irrigation. The rate of water flow was doubled from 25,000 to 50,000 gallons an hour which was more than double spray rates at the time. Still the money flowed the wrong way.

   While new ideas for irrigating were constantly being tried other experiments to improve soil were going forward. In theory and on paper a way had been devised for cultivating the land to slow down the run-off rainfall from the primary ridges and drift it toward the centre of the ridge, and to make the water drift outwards from the centres of the primary valleys. It was called Keyline 'pattern' cultivation, and now we would try it out.

   A hundred acres were plowed 'pattern' on dry land with an impliment half way between the later chisel plows and a road ripper. Some months later it rained during a weekend stay on the farm and an inspection was made of the 'pattern' cultivation. Where I entered the paddock it looked good. The rain was heavy, the run-off was held up nicely and spreading evenly and not concentrating anywhere. A dam some distance away was overflowing down a small primary valley. The water was doing exactly what in theory it had to do but it was hardly believable. Instead of flowing as it would normally do, about 12 feet wide, a foot or more deep in the centre of the valley and fast, the 'pattern' had taken complete control. The sheet of water was flowing 180 feet wide, covering from boundary to boundary the entire primary valley shape. The water out near the side limits of the valley, three and four feet higher than the centre of the valley, was the same depth as in the valley bottom. What I was seeing was a flow of water ten times greater than we had used, moving uniformly downward over a strip of land which sloped in three different directions. Keyline 'pattern' was a breakthrough!

   Pattern irrigation is based on pattern cultivation which in turn is based on the pattern of the contours of the various shapes of the land, (Chapter 4). Contours, which by nature are a uniform vertical distance apart, are parallel to each other on the vertical plane only. Marked in on the land with its varying slope planes, contours are not parallel to each other.

   Therefore if lines are made parallel to a contour on one side of it--on paper or on the land surface--the lines are not contours but have a slope. if other lines are made parallel to the same contour, but on the other side of it, they also would be sloping lines but their slope direction would be opposite to those of the first group of parallel lines.

   When the parallel lines are the hundreds of small furrows of chisel plowing they will influence water to spread or drift in one direction or the other, according to which side of the particular contour--upwards toward the higher country or downward toward the creek--the plowing has been done. Pattern cultivation is simply done parallel to a marked-in contour line in the direction away from it which will drift and spread flowing water in the opposite direction to its normal path; towards the centre of the primary ridge instead of towards the centre of the primary valley.

   The water for pattern irrigation usually comes from on-farm storages of two general types: firstly, from a large dam in a primary valley--at the Keyline or lower down--or a dam on a creek or other water course which has sufficient land below it for irrigation; secondly from a smaller dam sited high enough to which water is lifted by pump from a large lower dam or other source of supply. This dam may hold only sufficient water to irrigate once and then be filled for the next irrigation.

   The water flows from an outlet pipe in the dam directly into an irrigation channel which is wholly within the ground like a shallow trench. The channel is about 50 inches wide and 25 inches deep, and usually has a gradient of one in 300.

   Present outlets beneath the walls of dams, consist of two pipelines, one small inside a larger pipeline. The small line is one and a half inch bore to supply filtered drinking water from near the surface of the storage. It operates independently of the large steel pipeline--12 inches or 25 inches diameter--through which the irrigation water is released. This is in part of description of our Lockpipe System which is protected by various patent applications and designs registrations throughout the world.

   Irrigation proceeds in this manner--the area of course having been pattern cultivated within the previous three or four years: The operator is usually equipped with a long handled shovel and has three irrigation flags of registered design. A flag is made of a large piece of water resistant cloth, and includes a light weight pipe-bar to hold it across the channel, and a chain and spikes to hold the flag in position in the channel.

   To irrigate, one flag is placed in the channel near the dam and a second, 60 to 90 feet further along. The water is turned on full bore or to the full capacity of the channel, to be blocked by the flag and spill down over the land. The operator follows a set drill, releasing the water by moving the flags leapfrog fashion along the channel, to water the land uniformly and quickly. Various layout designs to suit all circumstances make pattern irrigation a one to three channel system, operated by one to two men to vary the rates of water application from ten to 30 acres per hour.

   For irrigating the City Forest on positively undulating land the channels could be concrete lined, a little larger, perhaps with slightly more gradient, for the same two men to control four times as much water as from a city of 200,000 people. The pattern 'cultivation' would be maintained forever, to spread. the water uniformly, by planting the trees in rows laid out on the appropriate pattern.

   Pattern irrigation spreads water in large flows, uniformly, quickly, economically and it is a soil making process.

   Flood-flo irrigation does the same things on gently undulating and flatter lands but it is much faster and even more economical. For instance a normal rate of irrigation on pasture land for one man is 33 acres per hour, but it is almost as effortless to irrigate 50 acres each hour.

   Flood-flo irrigation operates on these same principles of the natural movement of water flow over various shapes of lands, only the emphasis given by landscape design is different. For instance, on the more positively undulating land the natural movements of water are too fast and it concentrates too quickly. Pattern irrigation slows it down and causes it to spread in the right direction. But on land which has very little slope, water travels too slowly, spreads too widely and loses its togetherness and its power to move down the gentle slopes fast enough; too much water soaks into the land. Landscape design controls it but in a different fashion.

   The source of the water for flood-flo irrigation is similar to pattern irrigation. Because the landscape is flatter the dams are shallower and of much greater surface area and water holding capacity. The lockpipe system is always the larger size, 25 inch and they may be laid in duplicate. When the water is released it flows directly into an irrigation channel but the shape is different and there is no gradient; it is a contour channel.

   This is the design; the irrigation channel is constructed as a two feet or larger earth bank on a contour across the land, a mile or more long. The water flows on the land above the bank where it may be from 50 to 300 or more feet wide according to the slope of the land it traverses. From the irrigation channel the water is released on to the land below through sheet metal water gates six feet wide. The irrigation land 800 to 1,000 metres wide is divided into 'water fields' of ten or more acres each by "water-steering banks" which join up with the irrigation channel and fall directly down the land.

   The steering banks may be only a few inches high. They are placed on the surveyed lines of the maximum fall of the land.

   The full flow of water is released via the water gates to each water field in turn. The steering banks hold the water together to flow gently but faster than normal for flat country. Between irrigations, all water gates are left open.

   Should flood rains occur, the heavy rain run-off from higher land is automatically controlled by the irrigation channel to be spread into all the water fields through the open water gates.

   Flood-flo would be also the system of irrigation chosen for much medium undulating country, when the slopes are not too short.

   The land for City Forests would more generally be suited by Flood-flo irrigation. The amount of water which one man could control in irrigation would be three times greater than for pattern irrigation and 10 times greater than for any orthodox irrigation system.

   The design of both water systems--pattern and flood-flo irrigation--automatically design their own road systems for efficient forest management and, why not, for tourists. For instance a sizeable City Forest on some of Sydney's unattractive and not used nearby sandstone reserves, could be laid out on flood-flo water design. Roads with wide parking strips would cross the slope of the land at say 600 metre intervals alongside the line of the irrigation channels. Other roads would follow the layout of some of the steering banks up and down the slope.

   The roads would divide the City Forest into separate areas as did the farmscape and the cityscape design. These 'suburbs' of the City Forest could be adopted by schools or societies involved in landscape betterment--guardians of the environment. Children may like to 'people with trees' their own forest suburbs and watch the trees grow as they themselves grew up. My youngest son helped plant the six leaf seedlings for a strip forest and saw them grow to 60 feet high before he grew to manhood. The trees grew well and we did not have to wait years to see something. In 12 months they were ten feet high and in two years the strip forests transformed the landscape. But the City Forests, with the wonder-water of the city to irrigate the trees, would grow much faster.