[Time is not on our sides, it may be up to individual farmers to adopt methods of water conservation]
A principal aim of Keyline is to increase both the depth and the fertility of the soil so that the soil of farming and grazing land is safe and permanent and capable of continuous improvement.
natural soil are (1) the minerological and structural framework, (2) the prevailing climate, and (3) the soil's biotic associations.
Of the three factors which have determined the soil type (1) the minerologi- cal and structural framework is predetermined and not readily altered, (2) the climatic background is likewise fixed and not capable of control by man, and (3) the biotic association is susceptible to control.
[Stability is often lost when man interferes to create crop or grazing land, leads to decline in fertility and erosion]
[with proper planning man can have a beneficial impact in his interfering, increasing fertility and eliminating erosion]
[soil has its own climate (micro?) that can be changed, even when the larger general climate is outside of man's influence]
Keyline plans the evolution of the replacement landscape on the two most permanent features of the natural landscape, (1) the existing shape and form of the land, and (2) the climate, which in large measure has moulded and determined its present topography.
the factor of water is the one most susceptible to control.
waterlines are critical and invariably becotne the framework to the Keyline plan for the land. An that still applies even where water is in excess supply. All other constructional aspects of planning, such as roads, treeplanting locations for farm buildings and working paddocks, and subdivisions for crops, pastures and lives- stock, are fitted into the basic waterlines framework.
endless variations in their topography
the damaging and moisture-robbing power of drying winds may be appreciably reduced by the planting of tree belts
third factor of soil determination, the biotic association, is almost completely under the control of man
many plants themselves have the faculty of improving the soil and further modifying the soil-climate
The basic idea which I have attempted to convey throughout my work is continuity; that for all time the soil, like the crops and the livestock which it produces, persists and develops as thinking man assists nature by using and accelerating her own timeless processes.
agriculture is the human betterment of a continuous natural process
Is not the grass the great healer of land and do not his stock provide the accelerators for the soil-forming process?
The first aim of Keyline is to provide simple means of conserving all the rain that falls on the land into the soil itself, retard its evaporation rate and use the conserved moisture for the rapid production of soil fertility
Any property which includes in its area a watershed or water divide has one or more Keylines
A contour line lies at right angles to the slope of the land; as the slope changes direction the contour lines curve and turn
The distance apart [contour lines] is called the vertical interval
The space or interval between two contour lines is referred to as a contour strip.
[keyline is the inflection point of the slope]
Map 2 [pdf 22] Keyline/parallels
[cultivate the ridges above keyline plowing any convenient way, it will not affect the keyline system]
cultivation runs are again generally higher in the valley than on the adjacent ridges in the same contour strip
1. Rainfall on or near a valley rapidly concentrates in the valley and flows off the area, not only preventing the ridges from absorbing their fair share of the rainfall, but in poor soil, taking with it some of the soil from both valley and ridge.
2. Keyline cultivation is in effect many hundreds or thousands of very small absorbent drains, preventing rainfall from concentrating in the valley - thus resisting and offsetting the natural rapid concentration of this water into the valleys.
Very heavy rainfall, after it has completely saturated the soil which has been cultivated in that way, naturally starts to move to its normal concentration lines in the valley, But it is interrupted by the tendency of almost every cultivation furrow to impede it and drift it away from the valley. The flow movement of excess water is widened and its flow is kept very shallow. The necessary time of concentration is increased enormously, thus holding the water on the land longer. The land will have time to absorb the rain that falls on it. Rainfall of maximum intensity is robbed of its destructive violence.
Keyline diffuses rainfall evenly over the whole of the land to absorb it in the greatest water conservation storage area - the land itself
it plans the clearing to retain timber in the best places; it positions the house or homestead, all other farm buildings, entrance and farm roads, large and small paddocks, dam sites and irrigation areas. It guides the whole course and sequence of development as well as the details of all cultivation
A positive change must be made from extraction fertility farming to absorption fertility farming.
The first requirement, already stated, is the retention of all rainfall in the land for the production of fertility, and not methods to "safely" allow water to leave the property.
The best methods of soil development are the surest means of erosion control. Continuance of those methods will quickly produce as good, if not better, soil than that which originally existed.
Correct cultivation is a means of progressively improving soil structure and soil fertility, thereby developing a greater depth of fertile soil. Better crop production is incidental to the process.
[in soil building, but anything really] nature's methods do not take time into any serious account, whereas to us "time" is all important.
The processes which developed natural fertile soil are capable of control and tremendous acceleration. The dead stalks of plants, slowly laid down by nature loosely on the land surface, decay. That is one fertility process capable of acceleration. Each time decaying vegetable matter dries, decay temporarily ceases and fertility processes are slowed down. Processes of decay are increased when moisture is present. That decay, to all intents and purposes, is fertility
Man and his machines can stimulate decay and growth tremendously. When vegetation is stirred in the aerated part of the soil, decay continues for a longer period.
Some soil scientists estimate that there are 175 tonnes of living organisms and other life in a hectare of fertile soil [never given the consideration the sheep or cattle are]
Cultivation can be either the mammoth destroyer of soil fertility or the greatest single means of improving and even the creating of more fertile soil.
There is no sharply defined plant root zone in natural fertile soil. Shallow, medium and deep root growths mingle. Root decay acts to aerate the soil to an appreciable depth via the cavities left by the roots after decay.
fertility extraction = [mining the topsoil, instead we should feed the soil, not the plants]
The cultivation is to again unite the soil into a complete structure - not a topsoil divorced from the deep soil by a compacted layer.
New Keyline absorption-fertility cultivation is practically erosion proof; within a year or two of the resulting improvement to the soil, it is certainly so.
A good general depth guide for conversion year cultivation is double the depth of previous ploughing for crop productions, that is, about 203mm deep, and in the poorer soils 178mm deep.
[tines spaced farther than usual for depth cutting, try not to bring up subsoil, try to create uneven subsurface.][mouldboards (plows?) can work the top 100 mm after ripping with tines]
The standard shank row spacings of the Yeomans plough are 305mm apart, double the spacing of other farm cultivating implements. The Yeomans plough is equipped with tines, spikes or chisels 51mm wide
Eight kilometres an hour is recommended if the surface is suitable for that speed
That simple Keyline conversion year cultivation will start a cycle of soil fertility which can be carried forward to greater soil improvement and will produce a better than usual crop at the same time, it will also be effective in holding the soil against erosion.
For a short time decay does tend to rob growth of some of its requirements. Both decay and growth require among other elements, moisture, air and nitrogen. A crop sown immediately in conversion cultivated land may first grow weak and yellowed from the lack of nitrogen which has been absorbed temporarily in the processes of decay. With adequate moisture, air and heat, nitrogen will be available to the crop in a few weeks. The crop will respond with a rapid growth of healthy green foliage.
Continued year by year, Keyline absorption-fertility cultivation will keep adequate crop moisture available for longer and longer periods into dryer times. No doubt later on the "Keyland", one good season's rain will produce two years good crops.
[pasture lands are generally compacted by the animals (or machinery). This leads to less movement below ground of minerals and air (up and down). Humus does not form. Minerals are quickly diminished in the topsoil.]
Heavy soil will not remain open to that [deep, 600+ mm)depth but, will reseal with the first good rain.
[Rip deeper year after year to convert only a layer of subsoil each year. Owen mentions in Water and Transformation in Dryland Systems - Resilience Science & Keyline Application.mp4 that you can and should rip 18in soutthern NM. Do you now rip deep everywhere? Just in the semi/arid places?]
As soil becomes more and more fertile, less and less aeration by cultivation is necessary. Reasonably well managed highly fertile soil will look after itself.
earthworms.[do the cultivation]
Today most pastures tend to deteriorate, and those declining pastures are ploughed up, a crop or two taken and re-sown again to grass and legumes. The poorest pasture paddock is usually selected to be used in this way. If crops are to be taken on pasture land only good pastures should be used. Any farmer would be reluctant now to take this course, but if all his pastures were good, he may select his best pasture paddock for cropping. The farmer will select his best soil and pasture for his crops and so allow time for his newer and poorer pasture to improve with the soil before they in turn come up for cropping. [build soil fertility, feed soil not plants][harvest crops from most fertile areas while building in less]
The soil must always be considered first. Increase absorption, manufacture humus under the pasture, improve the structure of the soil, increase soil "life", then the improved grasses will readily assist in the full development of soil fertility and produce abundant pastures.
the greatest available water storage capacity exists in the soil itself.
Whether a farmer realises it or not, he is dealing with forces which need the full use of engineering planning. A sudden storm may send 100,000 tonnes or 500,000 tonnes of water on to a 405ha area in an hour or two. That huge weight of water can be controlled and conserved by the farmer to the great benefit of the land and himself, or it can run largely to waste, leaving a trail of destruction in its path.
Levels are important factors in any water control and conservation project. They need to be used to advantage by the farmer. Contours and other level considerations are basic land engineering factors.
On undulating country, dams can usually be located which will enable the farmer to enlist the forces of gravity to provide him with water under pressure.
With the Keyline positioning the highest suitable dam sites, it becomes important to locate potential water-shedding areas above the Keyline
[place homes/structures high on the land and capture runoff in the dams]
Where areas of land exist that are 15m or more vertically lower than the Keyline, the water from the Keyline dam will supply effective pressure for irrigation without pumping.
With the use of a 102mm pipeline, the vertical drop from the water level to a nearby irrigation area multiplied by .4 will give the approximate pounds pressure available in the spray line. A vertical fall of 15m multiplied by .4 gives 138kPa pressure, which is suitable for most types of spray lines. As the spray line is moved downhill a little on each "move", there is, of course, an increase in available pressure.
If the creek or drainage line below a series of valleys - as in Map 4 - has a general fall greater than 1.5m per 305m - the fall recommended for the Keyline drain - the direction of the Keyline fall follows that of the creek. When the creek has a flatter fall than required by the Keyline drain, the drain falls in the direction opposite that of the creek. That is illustrated by the shaded area on the map.
The construction of a Keyline dam will often cost considerably less than a pump and engine installed for spray irrigation. The Keyline dam, its pipe and valve outlet, will work the same sprays without pumping cost.
There is probably no other land development work which has been so completely unplanned and haphazard as that of timber killing and clearing, and no factor of fertility so completely ignored.
A fire in a timbered area, followed by heavy rain, is one of the causes of widespread land erosion
[timber strips, about the same distance between strips as height (13m trees 12m apart, 4m bushes 3m apart; 10 percent less than the height)]
[timber strips shelter livestock in summer and blanket them in winter. In rain the cattle stay on the drier timbered area, avoiding the wet grassland except to feed]
[timber strips should be ~20 m wide, below the keyline][prevents slippage of land in heavy rains, acts as an anchor]
ensure perpetual timber is by providing conditions to allow trees of all ages to grow together. If each paddock in turn is closed to stock and cropped for two years or more in each 10 or 12 years, young trees develop in the timber strips and permanency of timber belts is secured.
At the present time the rapid runoff from those lands directly causes uncontrollable and destructive floods, with losses of life, alarming destruction to property and stock, and the choking of rivers and harbors with silt. The trail of havoc extends from the mountains to the sea. [control rainfall/absorbtion in steep country; prevent it from building up]
At present, when a farmer leaves his steep country in timber it is usually because he feels he must do so. Sometimes it is left because he really wants to run it as a forest for profit or for general farm purposes. He thinks then that the steep country is the only place for such a forest. In the Keyline development of steep country the farmer has the choice. He can develop high quality soil and pasture, or if he wants a forest area he can have it in the steep country or anywhere else.
[ridges keyline plowed/swaled hold their fair share of moisture and prevent the valley from getting too wet to work]
With the high country in that condition effective gully control and repair in the valley below is simplified.
In the Keyline development of land, trees are not generally left in valleys except as part of a Keyline or guideline timber strip. The eddying of water caused by a tree in the path of the water flowing down a valley will often start an erosion gully.
It has been noted that a mob of cattle in a large paddock containing three timber strips at different levels invariably all camp in the one timber strip and spread themselves well along the line of this belt. A night or two later they will be together maybe in a higher or lower timber strip.
[treat flat land as if it was below the keyline]
Perhaps the main factor in determining the general guideline will be the position of a suitable conservation dam site [in flatlands] in the highest third of the area, and when located the general guideline becomes a suitable water race to the dam site.
If their vertical distance below the conserved water is sufficient, gravity spray irrigation is always planned.
[gravity spray irrigation adds] capital value of the whole property. [in the video, P.A. Mentions every 100 GBP (1955) invested would increase the land value by 1000 GBP]
leave suitable timber strips along the general guideline and all guidelines. [same as in sloping land]
Growing sufficient tree strips is the only possible means of reducing the high velocity of winds [erosion] to such an extent that the soil will not blow.
Indigenous trees can be induced to grow by leaving protected strips of land in the right pattern. That is the lowest cost means of growing the tree strips on a large scale.
The prime purpose of the lines of cultivation on the Keyline principle is to counteract the natural rapid concentration of rainfall into valleys by an induced drift out of the valleys.
Keyline cultivation, although it may start on the contour, is soon off the contour by parallel working. It is the off-the-contour effect which is controlled in Keyline to counteract the natural concentration of rain water in valleys.
[to start] a tree belt can be grown in two or three years in a paddock conveniently closed for cropping. The immense satisfaction from a successfully grown timber strip in the first paddock would certainly induce the farmer to continue the program into other paddocks when convenient.
the principle of locating some dams high on the farm is almost universally applicable and profitable. The design and the layout of farms should locate as many of the water-shedding areas and buildings as possible above the dams
It is a principle of the Keyline plan that all land on the farm is made to absorb all - or nearly all - the rain which falls on it.
Keyline work, by being complete and fully effective in each area on which it is applied, whether on the small paddocks of a farm or on a large grazing area, requires no outside cooperation or coordination. It is completely effective as an isolated unit.
Every farmer, by improving his land, is doing the best possible for the region, but he is still an individual working for his own pleasure and profit.
Keyline planning of a large area of land first aims to divide the area into smaller units or paddocks which are suitable for later economical development and farm working.
A map with contour lines at 6 m vertical intervals is suitable for land containing slopes from gently to steeply undulating. Three metre contours are suitable for gently undulating areas and 1.5 m for flatter slopes. [flat lnd should have 3 contours per large paddock to give a good representation of the land]
Watershed areas both small and large can be located at a glance. Keylines and Common Keylines are readily found on the map
"planning the work then working the plan"
The largest suitable land unit for planned development is that contained in the watershed of a river system. Within that large area of land are contained the many smaller watersheds of the creeks and streams which flow to this river. Again, within those smaller watersheds are the lesser watershed areas of all the valleys which flow into the smallest water courses. The lesser valleys are the valleys of the Keylines with which we are directly concerned in Keyline development.
The flatter top country above the Keylines contains all the buildings, yards and their roads, as well as the numerous smaller paddocks necessary for the running of all farms or grazing properties. Tree belts are left in the area as described in Chapter 9. Immediately below the Keyline are the large paddocks for grazing and cropping. The lower boundary of the area forms the top boundary of another area of smaller paddocks. They make use of the gravity pressure of the high dams for irrigation.
The cost of Keyline land development will be lower than the present development of such areas, but the actual cost of clearing may be higher because of the additional cost of the necessary planning which must precede clearing. Extra cost over the usual unplanned clearing may be involved by the necessary supervision.
On land already fenced there is no need to alter the present paddock layout. As Keyline is generally complete and effective in itself in any area small or large on which it is applied
It may be necessary to dig under a fence in constructing a Keyline water drain
First, conserve all the rainfall possible into the soil for the benefit of all the land, and for the production of high fertility. Second, conserve all water which flows from any and all high sources into the highest suitable sites in the Keyline - high contour and guideline dams. Third, provide for other and large storage capacity in lower sites in the contour dams of Keyline, the lower valley dam and the creek or stream dam.
The retention of more water in the soil by correct cultivation methods will provide extra profits. They should be used to pay for the capital cost of suitable dams for irrigation. In turn that will provide more profits.
An overall scheme of maximum water storage can be undertaken on limited finance when each new storage in its turn is used to promote soil improvement and more low cost high yields. Any expenditure incurred in the construction of such a scheme of progressive water storage, including the drains for conserving or conveying water, is deductible in arriving at the taxable income of a primary producer. [depreciate the costs to save on taxes; land improvement breaks]
The good farmer, by cherishing and improving the fertility of his own soil, is safeguarding the basic factors of the health and prosperity of every section of any community. At the same time he is in the first line of the general fight against disease. Fertile soil is the basic factor in the health of the community.
Whenever runoff water is artificially concentrated, an erosion hazard is created. Damage from public roads and other sources completely outside the responsibility of the farmers and graziers cause widespread erosion on the farmers' own lands
There is, however, no doubt that concerted actions by the community of farmers and graziers could do more in much less time to stop erosion and the shockingly devastating floods, than all the authorities concerned, even with unlimited money.
River and its eroding banks and flats would be protected by the farmer's work on his own land. Devastating floods would not occur again at such important population centres as Maitland or any other town on the river. Clear water would flow in the river all the year round and the flow would be more even and constant.
If we assume that the ancient flow of generally clearer water was compatible with the early better anchorages in Newcastle Harbour, may not a new flow of cleaner water result in gradually clearing the harbor, instead of the present continually increasing depositions of silt?
All the huge water conservation projects and all the special dams for flood mitigation will not hold as much water as the land itself if all the soil is kept in a condition to absorb the rain when it comes. Dams for flood control are effective if they remain only partly filled, so that large potential storage is always available to act as huge shock absorbers for the floods.
high contour dams and the others discussed in this book.
drought will surely have warranted the use of the water of those dams and their capacity will be available for the flood rains. [keep dams full just before dry season, use water as needed, drought conditions guarantee the dams will be low and mitigate any flood rains, keep dams low until end of rainy season]
There is no doubt that, at the moment, great flood dangers exist. There is also no doubt that projects of a national character in the construction of many flood control structures would greatly mitigate the danger of the big floods. Such works cost sums of money that to the ordinary mind are quite fantastic. They require for their finance a toll on the whole of the community. They cover with water large areas of very valuable land. [mega dams]
The phrase "Prevent erosion and save the soil that is left" lacks inspiration. Why not, say the farmer and grazier, forget erosion? Instead, build better soil structure, improve soil fertility, make, manufacture and create deeper, more fertile soil just by providing soil with the capacity to absorb fertility. If a sheet eroded area or an erosion gully is in the path of the better soil drive, convert it; engulf it in the waves of fertility.
If a shire council or the main roads board is causing large quantities of water to be diverted on to the farmer's land, thereby causing destruction, diffuse it, disperse it, absorb and conserve it in dams. It may be dirty water, but it is water. It is the greatest factor, in the average Australian farmer's mind, in fertile soil development and better yield.
Some of those weeds are likely to be of great importance and value in rapidly improving very poor soils.
<P>the irrigation-hectare, like most other things, has a "value" and since it is a production unit, so the value of it is closely related to what it will produce.
irrigation-hectare produced by large government undertakings costs much more to produce than it is worth when judged on ordinary business standards. The cost appeared to be upwards of $2500 per irrigation-hectare but no big scheme has been built since to give comparative updated costs. (Values throughout this book in Australian currency.) 
[large gov dam projects cost taxpayers lots and produce more expensive electricity than thermal. The argument that "free" irrigation is also provided is wrong because the taxpayers bear this cost. Wide-scale keyline deployment would be much cheaper, and the cost bore by the farmer.]
Does it not appear completely illogical in the first place to do anything about storing water in "big" dams for irrigation at such high cost and at the same time neglect the benefits of soil and landscape improvement and tremendously increased production, which are available so cheaply by simply improving on the use from rainfall where it falls?
For centuries has not a crowning achievement of civilization been in making the "desert bloom"?
there is no doubt that money follows the water
all the ordinary taxpayers of the state or nation be made to pay for something which will directly benefit just a few farmers and the local business communities [large dams]
[dams capture runoff water that has already traveled far and incurred much loss. Erosion is not prevented. as the total.]
runoff is probably somewhat less than 9 percent of total rainfall the loss must be considered a serious one from a national water use efficiency view. if total runoff is 9 percent what has happened to the remaining 91 percent? Water is lost all the way along the line - everywhere - and the farther it travels the more of it is lost. All the water which runs off the farms does not reach the river
the highest efficiency in water use can be achieved is on the land where it falls as rain. Therefore for agricultural purposes the water should first be used on the land where it falls or as close to it as is possible.
efficiency in water use is purely relative. Likewise so is waste of water.
paradox which emerges on many occasions. It often happens that the more water is used the more water is available to be used, and the sure way to really waste water is not to use it.
cost of water transport in water lost in large government supply channels
Generally in industrial processes the greater the production the less the unit cost, but no so with water and irrigation. The "big" dam, which from appearances, should provide storage for water at lesser cost a unit than the farm irrigation dam. But it rarely does so. One reason appears to be the far higher cost a cubic metre of earth for the wall of the "big" dam which is usually over 10 times higher than the cost for the earth placed in the farm dam. And the cost of transporting the material is a large factor in the comparison. Whereas on the farm, a dam site to be used has to have good earth for wall construction at, or usually within, the dam site, a suitable site for a "big" dam has no such favorable feature. The materials have to be much more carefully selected and invariably carried far greater distances. Concrete walls for the structures are much more costly.
The development of farm water resources would create a collectively vast area of irrigation land spread widely throughout all the farming and grazing districts. It would not be dangerously concentrated in the one place or concentrated on the one class of production.
The "big" dam will invariably be the best means for providing the water for the large centres of populations where the value of the water is high. But irrigation water from government sources costs the user from 0.12 to 0.24 cents a cubic metre ($1.50-$3.00 per acre foot) while city water costs 20-40 times as much. Therefore if the expanding population of a big industrial city wants the water of an irrigation dam, who is most likely to get the water? The irrigating farmer? Not likely!
once the water is on the farm and the actual irrigation is under way, the significance of the "size" of the government water scheme disappears. The water may have been stored in one of the largest structures man can make; it may have travelled many hundreds of kilometres in huge supply channels; been diverted by ingenious and costly control gates to several smaller and still smaller channels. But only when it arrives on the farm does the real irrigation project start.
In the government scheme large flows cannot be kept available for the irrigator for just when he happens to need or wants to use the water. In fact the opposite is the case; the whole working and management of the farm is usually ordered by the times when the farmer is allowed to take water.
Water from a farm irrigation dam, on the other hand, is not affected by such limitations
A government scheme, no matter how large could not supply each of its farmer irrigators with a flow of 5500m3 (one million gallons) an hour. Such an idea would be considered quite ridiculous, and such a flow completely uncontrollable by any irrigation procedure. But that need not be so on a farm. That large flow for some farm developments is quite practicable, being simple to design, economical of construction and fully controllable by one man and as a normal irrigation stream.
[Australia is] succession of droughts and floods characterises our climate. [but also SW USA]
Also the now ingrained "conservation complex" remains as a disturbing problem to overcome before all our land can reach its peak of development.
Whereas droughts are uncontrollable and, I believe, always will be and will always cost a lot of money, floods represent neglected opportunities.
<P>A day of sunshine following the 254mm of rain would give an appearance to the farm as if it had had a nice shower of rain the day before, except for the fact of all the filled dams and the water still flowing gently in some of the control channels. Those are what have been called the "damaging-flood-rains" of Victoria and New South Wales.
[much more than 250mm, in Queensland you could see 500mm+ rains, this would fill farm dams and overflow, but a far less overall flood]
assisting in the farm control of those waters instead of trying to control the water after it has reached the river
Floods cause heavy financial losses which are born by an unfortunate few. But the losses are quite minor from the national aspect and particularly so when they are considered against losses caused by drought. While comparatively few farms suffer losses by floods a very great number are greatly benefitted by the same rains. But during drought the position is reversed. Most farms and grazing properties suffer severe losses, some owners even to the point of the loss of their property, while only a few are fortunately placed to benefit from the disaster.
Artificial rainmaking does not appear to be a possible answer to droughts as there have to be suitable clouds on which to work and they are rare in drought times.
"...I had changed from a "conservationist" into a "developer"". P.A.
In Australia, with its generally poor soil and unpredictable rainfall, the word conservation is an illogical reference which should now give way to the more practical approach to soil and land "development", including as its main planning basis - farm water control.
If the Department of Mines was named the Department of Conservation that would be a practical use of the word, as every land should "conserve" those things which, when used, wasted or lost are gone forever. And doesn't that apply to such things as the base metal, the minerals of every kind and to our oil and natural gas? But to apply the word and the philosophy associated with the word, to soil and to water - the alive and the self-renewing, - if we permit them to be, - seems now as out of place as it would be to describe the world famous Haddon Rig sheep station in northwestern NSW as an outstanding example of sheep conservation.
Modern soil conservation was born of panic and pessimism in the depression days around 1930 in America and had two basic foundations: (1) the most rapid despoiling of soil in the history of civilization, caused by the failure to adapt the farming traditions of the older lands to the very different conditions of soils and climate of the New World, and (2) the worst and most strange financial depression in all history; a depression in which, in the midst of an overabundance of foods of all kind, organized society was unable to feed and clothe its people. - And so they starved in the richest country on earth
And the second foundation of the soil conservation drive was the most activating one, as it was used as the means of putting government money into the hands of a great army of unemployed and so to get the economy of the country going again.
The only sure and economic way to prevent soil erosion is by forgetting it and concentrating on soil and landscape development.
In my opinion the philosophy of conservation precludes the possibility of any method based on this misconception from being the best way to improve the land. And a great deal of money has been spent less effectively than it could have been.
It is past time now for governments in this country to reconsider the function of the departments of agriculture and the departments within the conservation department - water conservation, forestry and soil conservation - and initiate completely new and more logical policies of planning and development.
the irrigation of flat or nearly flat country. It has been named Keyline flood-flow irrigation
Keyline pattern of cultivation is designed to spread the irrigation water and so overcome its natural gravitational direction of flow, which would produce a more or less concentrated stream, down the steepest path of the land towards the valley below.
with steering banks the stream is held within a confined course, thus preserving its positive forward movement. That has to be understood - there is a great work force residing in or resulting from the sheer volume of a large flow of water. The Keyline flood-flow irrigation system is designed to use that work force with the maximum efficiency, both in its effectively spreading the water over the land and in the crucial intake of that water into the soil itself.
A Keyline plan is always individual to each particular farm or grazing property; the shape of the land in relationship to the water resources available for development is the deciding factor in the plan layout and in the methods of applying irrigation water to the land.
These privately owned on-the-farm water resources may be developed to provide the water for various systems of irrigation; thus any of the several methods of spray, flow or flood irrigation may be employed according to the particular circumstances existing on the different properties.
spray type irrigation has so dominated the thinking in that development that any mention now of "irrigation" from on-the-farm waters is often taken to mean spray irrigation only. There has thus resulted a complete neglect, even an unawareness, of every other method of applying water to the land.
[irrigation technique application areas overlap, there is no clear distinction on what irrigation should be used on a specific property]
But as a principal aim in irrigation should always be the application of the water to the land at the lowest possible cost, and as low manpower cost can be best achieved by increasing the area of land one man is able to control and effectively irrigate in a day,
the farmer or grazier should make it his business to know something of the intimate techniques of all systems of irrigation so that he may select the one which he will use in the development of the water resources of his own land.
...I am totally opposed to the general view of farm irrigation as a thing apart, having little to do with the general development of farm and grazing land.
The planning for the development of all land must have as its main object the maximum profitable use of every natural and renewing resource of the land itself, so that where water resources exist their possible use in irrigation is automatically a part of whole-farm planning.
there must be a capacity for assessing the development potential of the particular area. What constitutes potentials of land? How can the potentials be discovered and assessed? Not until satisfactory answers to those two questions are known is the planner in a position to plan.
the subjects of land shape and water being nearly inseparable
water lines. They are, first, the stream courses of every size and, second, the ridges which divide the rainfall water which falls and flows to the valleys and streams on either side of them.
just as stream courses have other streams flowing into them, so also do valleys have other valleys flowing to and joining them
Water is thus divided by ridges to concentrate as streams in valleys.
two "shapes" or "forms" of land then are ridge shapes and valley shapes.
the general order is that several of all the forms exist on each property.
Land can be said to have "length", which would be from the water- divide on the main ridge to the stream course below. Such length-of-land may be as "short" as 402m, or "medium" as 0.8km to 1.6km, or "long". "Long" or long-slope country may range up to some kilometres from the top of the main ridge to the stream course below it.
Primary valleys on undulating land contain the suitable sites for water storage, but those sites may not have satisfactory catchment areas within the catchment of their valleys. Water may be then diverted [from other surrounding primary valleys]
The highest suitable site for a storage dam in a primary valley of good shape for the purpose is just below the Keyline of the valley, where the wall for the dam would cause the water line of the dam to coincide with the Keyline of the valley.
it can be seen that the whole series could be interconnected by channels diverting runoff from valleys with no dam to the storages.
overflow of the higher dams can be diverted to one or more lower down in the chain-like series. (See aerial picture of Yobarnie dams and channels, Plate 5).
the best way to illustrate land on paper is by means of a contoured and scaled map. "contour interval" should be suitably selected to disclose the shape and the form of the particular land
with the aid of such a map of an individual property, an experienced Keyline planner could lay out a working specification covering the full development of the property, provided that he had a good knowledge of the climate and also had the landowner available to give details of the soil and other materials which the planner would need to know about particular locations on the land itself. Such a plan could then be produced in ample detail to include the manner and type of the water resources development, as well as the location and the most suitable size and wall heights of water storage structures the sites and sizes of water diversion channels and the location in relation to such works of irrigation areas. Even the appropriate irrigation procedures could be designated.
Stock watering points, farm roads and the positions to leave trees already on the place or to plant them, the sites for farm buildings, for subdivision fences and stock working paddocks - all could be decided quite competently without the architect of land development actually seeing the land itself. The plan could then be transposed onto the land either as a project or piece by piece as circumstances may permit or dictate. Such are the value of good contour maps!
Water follows the steepest path downward to the valley below it, therefore it flows at right angles to the contours, as that is the shortest distance between contours, and the steepest path
A contour map showing two primary valleys falling from the main ridge to the watercourse below and with a primary ridge between them Figure 3 [pdf 126]
The contour diagram illustrates flowing water. Upper: The flow paths of runoff water from the ridges to the valleys are flat S curves. lower: Depicting one flow path to illustrate the increasing volume of flow from the ridge to the valley. Figure 5 [pdf 128]
[more water gets into contact with the valley sp] in the dryer weather is the greener valleys and the dryer ridges.
[keyline cultivation] wherever it is desirable to spread water uniformly, or to cause shallow flowing water to drift one way or the other.
Two or sometimes three contours at selected distances apart should be used to guide the cultivation.
Figures 8 and 9 are contour diagrams of the same area of land. Together they illustrate the type of selective control of the first flow from runoff rainfall, or for spreading irrigation water. [Fig 9 would never be used in practice, it is merely for illustration.]
WATER PROVIDES THE MAJOR PART of the value of all agricultural land
there are two distinct movements or rates of movement of water into soil. When water is applied rapidly in irrigating a soil in need of water, there is first, a very rapid penetration of the aerated topsoil. Immediately on the saturation of that soil, which may be only a few centimetres deep, there is second, a very sharp decline in the rate of water penetration, as now more water cannot enter the top soil faster than it moves from the surface layer into the soil or subsoil below. The second rate may be more than 100 times slower than the first. When that occurs it is better that excess water flows off the land altogether, than the soil be allowed to become oversaturated.
[too much water leads to leeching minerals deeper]
[4 categories of water, 1 rain the falls directly onto land, 2 the runoff from #1, 3 runoff from outside the farm, 4 groundwater]
[when poor lands are restored to pasture, the land may absorb water more efficiently thus preventing runoff. When this occurs it may be necessary to leave some land undeveloped and used as a watershed or] it may be necessary to surface treat and seal some areas of land to turn them into artificial catchments to provide for stock watering and for homestead use.
any result from planning or design which retards the drying action of wind is another improvement.
[the higher the reliability of a water store increases the waste water it overflows.] That type of reliability is appropriate in the storages for the water supply of a large industrial city. It does not matter if four-fifths of the stored water is still available in the dam, and therefore wasted when rains fill and overflow the storage, and again may waste much more water in the second manner of overflow than the full capacity of the storage. In a similar fashion the large government irrigation projects with their vast storages and equally costly channels for water distribution and control are designed to have a high degree of reliability and therefore to waste enormous quantities of water.
[farms generally do not need such high reliability. Water can be used to irrigate, lowering the dams to make room for the next rainfall. The main point of a farm is having as much water as possible, wasting as little as possible while still remaining a farmer's degree of reliability.][stock water needs to have high reliability]
The traditional ideas about water from the older countries with climates less harsh than our own, and the many academic and scientific dogmas and conceits relating to water generally, should now be abandoned in favor of some realisitic and practical thinking and acting on these matters
In the development of his land's own water resources why shouldn't a farmer be able to think of his stored water as a second bank account? Provided he can take the water out of the dam quickly and at a very low cost and can spread it over his land with similar speed and low cost, he can thus "trade" the necessary water for the crop he wants or the pasture he needs for his stock. And why can't he continue to do just that and, if need be, use up all the water of the storage? True, he is then without the water, but he has more than the value of the water in what the water had "bought" in crops and pasture. An empty water storage dam then is not the sign of failure but quite the reverse.
[water can be shuttled around between dams using drainage pipes and contour swales/channels. This water can allow irrigation on (m)any parts of the farm. Local conditions and dam size will play a role in how and when you irrigate. Ideally you will run out of water just before a replenishing rain, but rarely can this be timed perfectly.]
minimum annual runoff
dumpy or Bunyip level
a great deal about his land is learned by the farmer in the course of pegging the "new" water line.
final results should be two or more interconnected storages in which the overflow from the highest dam is caught by the water- collecting channel and directed to the next lower dam
it may be found there is more water available than was expected and which the limited layout can use. Then it is a simple matter to add more storages
The critical factor in the rearrangement is that the top water level of any new dam should coincide with that of the diversion channel on the down side of the valley, as that is the level at which the spillway of a new dam must join up with the diversion channel.
The higher up on the landscape that water can be made available the more valuable is the water, and the greater is the area of land which lies below it and on which it may be used.
irrigation bays or waterruns may be 20 to 40 times larger. With such large bays, land preparation is totally different and instead of relying on extensive and expensive levelling and grading work to ensure an even spreading of a small stream of water, as with border check irrigation, the large flood-flow streams plus Keyline pattern cultivation, accomplish it at around 1/10th of the cost.
Whereas the more orthodox practices treat soil as if it were a static substance but one which could deteriorate, Keyline regards any existing soil as essentially the home of an organic community of living things which can be improved to a much higher degree of fertility.
fertile soil, when it is somewhat dry, will literally gulp water almost as fast as it can possibly be applied.
infertile, as they almost always are, and as a consequence do not absorb water rapidly
We may read that a certain soil when dry "takes in" 13mm of water in half an hour but very little more in two hours; perhaps that in 10 hours it still won't absorb 78mm of water. In Keyline we are not concerned with such times but in how much water the soil will accept in the first 15 seconds, half minute, or 10 minutes
A sponge plunged into water is hardly any wetter after 10 hours immersion than it is from 30 seconds or from 10 minutes immersion
[install modest dams on streams, the size in accordance with the irrigation cycle. If you need to irrigate about every 10 days, build the dam big enough to fill up in 10 days. It can then automatically tip a watergate and irrigate the area.]
[using water gates over lock-pipes allows for a little more gravity to be accessed on flat lands.]
two prices to be paid for water, the second being the cost in water itself. The second cost in water lost in the transport of water via channels becomes continually higher as the distance which the water is transported becomes greater. The enormous loss of water from government irrigation supply channels is a matter of continual concern. But the solution to the problem of water lost by seepage and to a lesser extent by evaporation is enormously costly. It could involve the concrete lining of hundreds of miles of main supply channels or, alternatively, the replacing of channels with huge pipelines.
But there are no such problems with the use of channels for transporting farm waters around the farm. Here the channels are cheap to construct and they don't waste water
distance the water travels is, by comparison, insignificant. Moreover its spread of travel is considerably faster
when the largest farm channel, the diversion channel, is carrying its greatest flow of water it is sure to be raining heavily. Where then are the seepage and evaporation losses? On the other hand the government supply channels are very large and carry their greatest flow in hot, dry weather when all farmers would like to irrigate their land.
If there is a little seepage water, it will in all probability be only slightly less valuable than the controlled irrigation itself. [on the farm channel]
two principal uses for channels: first, for the diversion of direct rainfall runoff, stream flow and pumped water into a dam for storage and second, for carrying water to a specific area for irrigating the land.
[channels need to be small enough to step over or straddle on a small farm]
there is no reason why the system could not be made larger and designed with bigger channels to carry twice the water for two-man control.
FLATTER LANDS signifies all land having fairly uniform slopes with a fall of from 1 in 40 to 1 in 10,000 or even flatter. It is to be noted that the cut-off point in the classification of undulating land and flat land can not always be precisely determined
On the steeper of those flat land slopes of from 1 in 40 to say 1 in 100, the irrigation channel is formed by a single earth bank about 0.6m high, which is constructed across the general fall of the land. The irrigation water then flows on the land on the upper side of the bank. The width of the irrigation stream will thus vary according to the volume of flow and to the local slope variations of the land immediately above the irrigation channel bank
where the slopes are flatter, the irrigation channel is formed by two such earth banks constructed in parallel from across the fall of the land. [width determines flow rate] the channel should carry its full flow of water with less than 305mm depth of water against the single bank or against the lower of the twin banks.
The starting point of the irrigation channel is at the delivery point of the irrigation water. 1) at the lock-pipe valve, (2) at the watergates, (3) at the delivery or discharge outlet of a pump, (4) at the point where a diverted stream arrives on the area to be irrigated.
[bottom level of irrigation channel should be level with bottom of lock-pipe, or up to 0.3 m lower. The pipe may become partially or fully submerged with the back-up flow. You will lose some flow, but it is minimal.]
[the depth of the dam and pipe diameter, for lock-out, will determine the pressure.]
[if flow backs-up from a watergate, the flow will be greatly reduced.]
pressure water from lock-pipe or pump flow may on occasion be raised 0.3m. That would involve higher banks on the irrigation channel for a portion of the length at the end near the water inlet, and the creation of a pond area to raise the water level the extra 0.3m to cause it to flow along the channel. [this will reduce the irrigation ability when the dam nears empty, but can offer a great deal of extension to the irrigation field.] For instance, where the land has a general slope of 1 in 2000, the extra 0.3m adds a strip of land for irrigation 610m wide and for the full length of the irrigation channel.
My own designed Bunyip level of the second type consists of a length of 60-feet of half-inch transparent hose with five feet of each end fitted into two specially shaped metal staffs which are graduated in feet and inches to a sixteenth of an inch. Each end of the hose is fitted with control buttons which in use are pressed to allow air into the hose. The hose is filled with water to within a foot or so of each end. In use, one staff is set up at the starting level point by one man while a second person selects a trial position a hose length of 15m away. Each one then presses his "atmosphere" button which allows air to enter and permits the water in the hose to find its own level. The water level is then read on each staff.
[in the irrigation channel] the lower the flow volume of water, the more necessary becomes the need for a fall in a channel and the more positive should the fall be as the flow volume decreases. But as Keyline flood-flow irrigation employs much larger flows than any other irrigation system there is no need here to consider lesser flows and their channel falls. There, a perfectly level or contour irrigation channel becomes the general type.
when there is any doubt as to whether or not a fall should be given to the channel, then a contour line should be pegged for observations to assist in making a decision.
[Peg contours at 15 m]
So in walking the pegged line to adjust it, it is well to carry pegs of a distinctive color. Then, when an original peg appears out of the general pattern of the line, the spot is examined to see whether because it is on a local high or low spot, it can be moved up the land or down the land and so improve the line. The old peg can be left for the moment and a new peg of different color placed in a better line position. A better and smoother shaped line can thus be produced and still remain for all practical purposes on the true contour. We have called the action of adjusting the line "normalising".
Although it is important that the general aspect of the line is that of a contour, it has been found from experience that purely local small variations in level matter little and even less so as larger flows are used.
[clear the land of grass when you are going to dig the channel; makes it much easier to see][smooth "flow" from peg to peg, not a series of small straights]
In conditions of climate that are hot and windy, it is desirable to adopt special measures to quickly grass the irrigation channel banks. By placing earth stops in the excavated drains beside the bank, ponds of water will lie along the sides of the bank after each irrigation, and the ponds, by keeping the adjacent soil moist for some time after each irrigation, will greatly assist the spread of grass over the bank.
There are two parts to a Watergate: (1) a frame in channel iron form which has a continuous fin projecting outward from the bottom and both ends and (2) a separate closing panel formed of sheet steel. The closing panel slides in the channel form of the gate frame and an effective water seal is obtained with a strip of sponge rubber which is attached around the contact edges of the closing panel.
It has been found that the most practical procedure is to start the first full irrigation as soon as possible and use the watergates with a full flow of water. [to test for soil disturbance; walk the channel while irrigating. The water may be cloudy and you can't see everything. Come back the next day and look for sol disturbance.]
There are other advantages in management, as the area of the flood-flow irrigation channel itself is far from wasted, but instead is part of the irrigation land. It may be sown to pasture and grazed, harrowed and mowed with the rest of the area.
[on the irrigation channel] all watergates are opened the day following irrigation and remain open until the start of the next irrigation.
particular importance that the design and layout of land for any type of irrigation should be such that the water from occasional heavy and continuing rain immediately after an irrigation is handled effectively and automatically and without damage to the soil. Hence the importance of having watergates remain open after each irrigation is completed when there is any chance of rain. Stated briefly, "good irrigation layout is automatically good drainage layout".
subdivision fences should not "fight the water" by crossing the bays on an angle, but should obviously "go with the water". Fencing is therefore associated with the pattern of the steering banks. They should follow the steering bank which, first of all, suitably divides the area in two.
Steering banks are located by a levelling instrument - not by eye.
[bunyip level] readings are taken by each man and the variation in the height of the two staffs noted. The reading of the forward staff is particularly noted. Now, with the back man maintaining his staff position, the forward man begins to take more readings as he moves his staff to three or four positions on an arc of a circle, with the radius of the circle represented by the 15m measure of the level. He selects the point, the lowest of the series of readings, which is then the highest spot 15m distant upland from the start, and places a peg against his staff on its lower side. Now both men move forward the back man to the second peg just placed by the forward man, and the forward to a new position as before, where by taking readings on an arc he again finds the highest point and then places the third peg. That method of pegging continues upwards to the irrigation channel and finishes about 20m beyond the channel on its upper side.
If the vertical height from the start to the end of the line is required, then a record of each set of readings of the Bunyip is kept. The total of the differences in readings then is the vertical height.
whenever there is any doubt about the course to follow the level alone should guide the issue.
[45 m between steering banks. These are the basis for fencing and irrigation bays]
[steering banks are built at the points of highest fall down a slope.]
normalising then is to produce the lines as the contour would have been if some of the surface had not been slightly altered .by wind erosions.
fig 16 [pdf 187] the series of crosses represents the pegs as placed with the aid of a levelling instrument, wavy line represents the line as normalised, line form of the series of straights represents the nearest to the true line practical for a steering bank which may have a fence on it
In some circumstances the pegs, as represented by the crosses in figure 16 may not favor normalising because of wide variations from any form of line. They will, however clearly indicate the true general downhill direction
For beef and other types of general production it has been found from experience in the management of irrigation land, and including the various systems of flood and flow, that where water is distributed from channels, 6.4m and 9m are suitable minimum and maximum distances for the fence position from the nearest bank of the channel.
the belt or lines of trees can be suitably associated with the subdivision fence which divides the irrigation land from the rainpasture land above it.
making the best possible use of every natural and renewable resource belonging to the particular property itself. [keyline approach principle]
Water and rainfall are thus the bases of land development planning.
planning of the development of land should be based on permanent factors, namely, the twin agricultural permanencies of land shape and climate.
planning resolves itself first and foremost into an understanding of the two factors of land shape and the related water movements.
[plant shelter belts and tree belts that can then be perpetually harvested for fence posts]
Keyline water control systems on both hill land and flat land could make reafforestation on a grand scale both practicable and profitable.
[chisel/tyne plows are the best for fertility building. Deep, allow water/air penetration. They don't sow seeds as well as mouldboard. Mouldboard and disc can seal the topsoil preventing water/air penetration into the subsoil.]
[in cool, high rainfall climates it will generally take a long time before any noticeable degradation occurs, while in dry, tropical areas the degradation will be apparent immediately.]
The shape of the irrigation channel gives an immediate clue to the shape of the land of the irrigation area. If the channel is close in form to a straight line the land shape is extremely large and very uniform.
where the irrigation form has produced curves which swing both upward towards the rise and downward towards the fall of the land, the curves clearly indicate the presence of both valley and ridge forms, even though the forms can be so flat as to escape the notice of the naked eye. But the water flow will be affected by the shapes, and if no measures are taken to spread the water it will follow its natural path somewhat sideways from the flat ridge form to the flat valley form, to the extent that it can do so within the limits of the steering bank sides of the irrigation bays
The good, complete and fertile soils of nature are not associated with the higher rainfall areas but with those where the rainfall is from 406-762mm a year. [irrigating much over this will induce leeching]
Dr H.H. Bennett wrote in his book Soil Conservation [when? 1900-1950 est] "Lack of foresight and restraint . . . has created in this country a land problem of tremendous implications. What makes the situation so grave is the irreplaceable nature of soil. Once this valuable asset leaves a field, it is as irretrievably lost as if consumed by fire. Soil is reproduced from its parent material so slowly that we may as well accept as a fact that once the surface layer is washed off, land so affected is, from the practical standpoint, generally in a condition of permanent impoverishment. As nearly as can be ascertained, it takes nature, under the most favorable conditions, including a good cover of trees, grass, or other protective vegetation, anywhere from 300 to 1000 years or more to build a single inch of topsoil! When seven inches of topsoil is allowed to wash away therefore, at least 2000 to 7000 years of nature's work goes to waste."
April 1965, American Agricultural Trends: Small Sheet of Topsoil Sustains World's Life, read: "All the world's human life depends on the fertility of a thin sheet of the earth's topsoil, covering 1/10th of the earth's total surface and forming a storehouse of plant nutrients only about seven inches (17.8 centimetres) deep. It takes about 1000 years to build up one inch (2.5 centimetres) of topsoil. Wind or water can take that much away in a few months unless the surface is protected."
hopelessness is official, and mistaken conceptions of soil still so widely promulgated, that farmers and graziers are adversely affected and their land suffers needlessly [soil can be built very fast]
The mineral world of the soil is composed of the dust and rock debris of the decomposing rock surface of the earth. The process of rock disintegration, the movement of the detritus from place to place by all the natural forces, the reassembly of the particles into later rocks of different character which were again decomposed, the addition to the original materials of reorganised mineral products from various forms of past plant, animal and sea life and the constant classifications of all the various dusts by the agencies of wind and water, has been going on for many millions of years. Moreover, much of the present agricultural land of the world has been once, and some of it several times, beneath the oceans.
[but now enough materials have been "released" into the environment/deeper in the soil. These materials can be arranged to produce soil quickly. The biotic aspect, growth mining the nutrients from deep and bringing them up as well as air/moisture/decay is rapid as long as conditions are correct.]
In rapid soil forming process man can interfere and so control and speed up the various biotic and soil climatic forces involved that he can transform the plentiful inert soil-materials into the complete world of the soil in as little a time as two or three years.
chisel plough (which does not turn the soil upside-down)
inoculated legume seed
In his book The Geographical Basis of Keyline, J. Macdonald Holmes, Emeritus Professor of Geography at the University of Sydney, observes of just such a soil program: "The soil he dug for us was a revelation . . . the three year course of Keyline cultivation had developed an extraordinary depth of dark soil just teeming with soil life, while the pastures were thriving."
[dead roots of grazed grass (anything really) provide food for the soil life.]
So with good living conditions - moist, warm and well-aerated soil - and a plentiful food supply (the recently dead roots of grasses and clovers), the soil species available from the atmosphere and the surroundings and from the rumen, glands and other organs of the stock, developed rapidly to a climax.
we did not know the complete story [of how soil is created] and never will - we had discovered only how to create the situation rapidly.
agriculture itself can be a soil-making process.
The diluted acids used in soil tests do not disclose the great truth that soil minerals can be at one and the same time (1) insoluble in both water and the test acids and (2) available to the plants by other soil processes. Indeed if nutrient minerals could not be both "insoluble and yet available" they must have all been leached from any worthwhile agricultural soil long ago, since only the lack of rainfall would have allowed them to be retained in the surface soil or shallower sub-soils.
[minerals locked up in the soil can be made available when life returns to the soil via decay/air/water.] soil-climate.
pasture on a 51mm (2 inch) soil, we would literally tear it to pieces with a chisel plough, but digging no more than 75mm (3 ins) deep. The cultivation would be timed to suit warmth and moisture conditions. Then the soil and pasture would be managed as we had done before by giving the pasture its time to grow after each eating off. The same timed cultivation once each year for three years would be given while continuing that same pasture management
At the end of that time the soil would have available to plants at least a goodly portion of the minerals which it did contain. On the "climate" improved soil all the trace element tests and experiments could be conducted. My opinion was that the tests would then tell the truth.
dams for irrigation, the most efficient siting in their relationship to both the land shape and to each other, is of such significance for controlling and for using the water to increase profits, that the manner of those things may dominate all development plannings
Professional engineers, with their sights set for only the bigger projects, have overlooked them, and naturally so. Government engineers whose job it could be to concern themselves with research and experiments which would promote the maximum practical use of farm waters have never been given the directive or the money by any government to do either. They are usually not permitted to depart from the orthodox, or even risk one failure which could at least provide some new and valuable knowledge.
on the flatter lands the water-earth ratio may be outstandingly favorable as for instance where a relatively inexpensive wall may back up water 150m or 300m (500 or 1000 ft) for each 0.3m (foot) of height of the wall.
Take the square root of a figure which represents four times the maximum catchment area in hectares of the dam and call the answer the width of the spillway in metres. Therefore if the catchment area of a dam is 16ha (25 acres), of which the square root is 4. The spillway width is thus 4m (10ft).
A minimum width of 3m (10ft) suffices but if the crest is to be used frequently as a roadway, a more suitable width would be from 4.3 to 5m (14 to 16ft)
Different slopes for the inside and outside batters are frequently recommended as that is the way with the "big" dam, but in 25 years of experience in the design and construction of farm dams, I have found there is little for, and much against that practice. The one slope for both batters is much more practical for farm dams
[1 in 2.5 is a good slope for both sides of the dam. 1 in (height) is even better.] so the toe of the batters would protrude from each edge of the crest two and a half times the height of the wall, which is 17.5m (58ft 9ins). Therefore with a crest width assumed of 3m (10ft), the maximum width of the base of the wall in the centre of the valley would be 38m (127ft 6in), made up of twice 17.5m plus 3m width of crest.
Mr Fietz' tentative conclusions are taken directly from the report ...
? "in this case the soil compacted at a soil-moisture content close to optimum."
? "With Keyline construction (which means in effect a particular pattern of earthmoving through the borrow area and onto the wall) the compaction achieved with the D6 (Caterpillar) tractor was close to the maximum obtainable with the Harvard Compaction Test."
? "Seven months after completion the embankment had settled 76mm (3ins) in a wall height of 5.4m (18ft), ie a settlement of 1.4 percent. That figure indicates that thorough bulldozer compaction in County of Cumberland soils (earths) makes it unnecessary to provide the customary 10 percent allowance for settlement."
University of New South Wales Water Research Laboratory Report Number 57, titled Research in Soil and Water Conservation Engineering, Progressive Report Number 2, 1960-1961, pages 17-19 and dated January 1962.
The dam in question has remained in first class condition through the rains of one major flood and two severe droughts. Shrinking and settlement of the wall needs to be provided for by adding 2 percent to its maximum height [other soils may shrink differently]
[step 1 construction is to remove the top soil. ~3 in. To make it easier to get just this, a chisel can be run over the area first. Place the top soil out of the way, it will be used later]
[cutoff trench located exactly below where the crest will be. Prevents leaking under the wall. 3M deep or a little more, to bind with acceptable material.]
level, the bottom of the pipeline, from the valley bottom, and therefore is located just far enough out from the bottom of the valley so the excavation into suitable material will bring the trench floor to the correct level
[another trench crosses the cutoff trench perpendicular for the lock-pipe. This trench may be shallower than the cutoff trench. The lock-pipe trench is always dead level.
[lock-pipe system first used at] Yobarnie in 1945.
It consists essentially of anti-corrosion treated heavy steel flanged pipes and gaskets, steel baffle plates and U-shaped rubber gaskets, screened inflow cone of special shape for the inlet end of the pipeline when laid, and a valve for the water outlet, plus of course, the necessary bolts, nuts and heavy duty spring washers.
[extra care should be given to the ramming of the earth around the lock-pipe to prevent seepage. Baffles are employed also. Perlite may help.]
the highest level over the central low area of the valley bottom. From that stage to the time when finished levels are being considered the central area of the wall should be maintained as the highest point with a slope of about 5 percent along the length of the wall from the centre to each side.
Usually the construction of the spillway will produce a surplus of earth which is then used in the building of that end of the wall.
0.9m of wall everywhere above top water level at the point where water starts to flow out of the dam and through the spillway.
the spillway carrying little more than 0.3m of water across its full width and when that happened there would still be another freeboard of 0.6m to compensate as a safety measure for bigger floods. (50 year [100+?] flood records)
Larger spillways are necessary for farm dams built in the lower parts of large primary valleys and for creek dams, as they usually have considerably more catchment area than a dam higher in a valley.
[flat lands and large dams' spillway may require lots of earth to be moved. Be sure to finish the spillway before the dam wall is finished. This way you can use the moved earth in the wall.]
With the outside wall batters strictly maintained on a straight line and at the correct slope, the front wall will gradually steepen from very flat slopes towards the final finished batter.
The crest of the wall should be finished off with slightly rounded edges. If it is finished off haphazardly with a bulldozer there is likely to be a small windrow effect left by the blade. When rain falls that could cause little ponding areas, which eventually break in one particular spot and water flows down the wall in a concentrated stream. More rain falling on the wall takes the same path and sufficient damage could take place with a few millimetres of rain to spoil the appearance of the new wall and necessitate some repair work.
A dam may be considered to have a minimum shape if the length of the dam is equal to the length of the wall.
The depths of farm dams and the height of the walls are determined individually for each site. The principal considerations are (1) the slope of the valley floor and (2) the water capacity of the site.
Walls over 9m high should be individually designed on the more orthodox engineering lines.
A good safe maximum for a farm dam in medium undulating country is a 6m (20 ft) dam with a 6.9m (23ft) wall.
If a dam 6m deep is considered to be a good working maximum then 3m (10ft) deep is similarly a good working minimum and the large majority of farm dams for irrigation would fall in that range .
as the land considered becomes flatter, the water storage requirements tend to be satisfied with lesser wall heights.
flatter valleys tend to become wider and so the walls for dams in them will be longer. There a 6.9m wall becomes an increasingly larger undertaking. In such cases the first checking of a proposed flatter site would be made by pegging it as for a dam 3m deep or a wall height of 4m (13ft), and by increasing the size if that proves smaller than the requirements.
On land which is generally considered to be flat and dry, the primary valley shapes of Keyline still persist but may not be obvious to the eye.
The walls for such storages need be little more than long low barrages up to only 1.8m (6ft) high. [this will be used up quickly and with such a shallow large area, would evaporate easily] In the bottom of the dam a deeper and smaller excavation could remain as a stock watering point.
a contour dam may be used to advantage on slopes which contain no valley form. That dam is essentially a long earth wall of medium height constructed from earth which is excavated from immediately above the main wall, and with wing-walls made to taper up the slope to above the water level of the dam.
In the flat lands all design features of the dams are flatter; the dams themselves are shallower, the water diversion and irrigation channels are both flatter, but the irrigation channels are built up so that the water flows above the level of the land.
Contour dams can be constructed on slopes ranging from 1 in 25 (4 percent slope) to 1 in 100 (1 percent slope).
[in contour dams] The position of the lock-pipe may be in any portion of the length according to where the water is to used.
The price a cubic metre of earth moved in a contour dam of lesser wall height will be considerably less than in the higher-wall dams. The average haul will be less, the push up the batter of the wall is shorter, and more of the work, which is only shallow digging, can be performed in second gear.
[ring pumps are the only way to store water above ground level on flat land, but require that the water they store be pumped in]
As mentioned earlier, I do not fully subscribe to the belief that food supply will become a critical shortage factor in population trends. Transport and exchange of food supply may fail. - However, whether prices tend lower or not, lower costs and higher yields from continually improving soils are satisfactory aims themselves. The potential of farm water resources is of outstanding importance in Australia both nationally and personally to tens of thousands of individual farmers. Anyone in authority who, presenting broad aspects of the developments of farm water resources for irrigation to the landowner or student, disregards relevant facts and does not mention even the possibility of applying water to land by systems other than "spray irrigation" is doing a disservice to Australian agricultural development. Irrigation from the water resources of our farm and grazing land should be made as profitable as is possible, and as was mentioned early in this book: "Whether irrigation will produce much profit or result in substantial losses often depends on just the right choice of irrigation procedure."