WATER supply is third on the Keyline scale of the relative permanenceof things agricultural. To nations as well as to farmers water supply is often aconflict and a dilemma.
In the discussions on climate the reader will have been consciousof the fact that land shape intruded. By the time the first two factors of the Keylinescale, namely climate and land shape, had been dealt with, water supply had alreadyfigured prominently. Throughout the discussions on the Keyline scale, the variousfactors show close interdependence upon one another and that many relationships existbetween each and all. It has been clearly shown also that this relationship, so typicalof agriculture, points to the need for a more practical approach or some basic guidein these matters which could prove or disprove the validity of such a concept asthe Keyline scale of permanence.
Climate and land shape have their degree of permanence throughno effort of man, but water, suitable agricultural water, is not always naturallypermanent. It has to be made permanent for successful agriculture, and the supplyhas to be completely reliable. House water and stock water are naturally permanentin some circumstances, such as from springs and rivers, but under Australian agriculturalconditions, in which water is always the critical factor, permanent natural wateris seldom adequate or suitably distributed for basic planning.
"If water is critical none should be wasted" is theKeyline aim and the guide to planning.
The greatest environmental change that can be made even whenthere is sufficient rain water for agriculture, occurs in circumstances where thereis a lack of long-lasting permanent water supply and when the incidence of rainfallis inadequate or wrongly timed. Where natural supplies are insufficient, dams thathave been constructed for irrigation can also provide stock water, and the requirementsmay be satisfied by as little as one per cent. of the total storage capacity. Thelocation and the design of dams to conserve water are based firstly on climate andland shape. These two factors must always be studied together. Good physical sitesfor water storage are only suitable if they can be filled. It is the definite aimof our plan to convert what at first appears as an impermanent supply into a secureand permanently conserved supply. The water aims of the plan then are, firstly andin order of preference, to make provision for household and stock water supplies,then to prepare the land surface where necessary so as to get sufficient rain intothe soil from each rainfall to promote the increased development of the soil. Thisprocedure, and with other controllable conditions, will cause an improvement in soilclimate. Again, all the run-off that comes from ordinary rain must flow into farmirrigation dams. Finally, all the flood rains that can possibly be held and be usedprofitably later must be diverted into all types of storages whose capacities havebeen planned to these ends. From my observations there are few areas in agriculturalAustralia where this cannot be done.
All high conservation sites where sufficient water can be broughtinto them by water conservation drains constitute the highest value in water storage.Such dams generally are to be used for irrigation immediately when irrigation wouldbe beneficial. This could be as soon as seven or eight days after rain in the summermonths. The next lower sites, there may be fewer of these and they are often larger,are to be held in reserve as "reservoirs" until the irrigation water ofother sites is nearly depleted. And finally come the lowest or "lower dams"or series of dams, which generally have the largest storages per dam but which maybe fewer in number. These last are usually pumping dams and are used for generalirrigation water.
The picture then is of three types of dams--(1) the high series,which may be true "Keyline dams", in suitable undulating country; (2) intermediatedams, i.e., reservoirs; and (3) lower dams.
Some or all of these dams will be used for other than irrigationpurposes. A suitably placed dam can be used as a house supply or to supply stockwater via pipelines and troughs, and sufficient reserves will be held for these purposes.Generally speaking, the more efficient and complete the use of water on a farm themore it becomes necessary to increase the number of stock watering points. With fullwater control from Keyline planning, the farm environment improves, the soil improves;the pasture, crops and stock improve in health and condition and their numbers mayincrease many fold with the growing capacity of the property. Increased stock numberscalls for increased watering points and for good management. A property now servedby six water points may require, and very profitably employ with better development,thirty watering points. Happily, the supply of such watering points is a very simplematter in the general water conservation planning of Keyline.
The whole question of the planning for farm water supplyneeds critical examination. There are recognised Government authorities on farm waterconservation who are doing their best to educate farmers on these matters. Soil conservationistsalso consider water and advise the farmer on how to avoid the menace of soil erosionby water. And there are others, in fact many other sources of agricultural adviceprovided by Government agencies, but the advisory authorities are often at variance.The approach of the usual water conservation authority influenced by a concentrationon his particular branch of the subject and often lacking a suitable background ofagricultural knowledge, is on a somewhat different plane to the soil conservationistand the agriculturalist. Generally speaking, the Government soil conservationistmay not touch the work of water conservation on the farms and grazing lands exceptand only insofar as it concerns his work of providing and advising on means designedsolely to conserve soil, and so the provision of a small almost useless dam as a"gully block" to stop soil erosion is as far as he may go.
The water conservation authority in New South Wales who controlsand designs dams and who advises farmers on farm water conservation may not haveanything to do with soil conservation, and if the dam is likely to silt up, thatis not his concern; it belongs with soil conservation. What is the upshot? Do wefind the agricultural officer co-ordinating this frustrating division of authority?Indeed no; he is often careful not to mention either soil conservation or water conservation--ithas nothing to do with him. But he is wrong. Both soil and water, indeed every agriculturalaspect of soil and water, should be his concern. If he is not the prime authorityon these basic agricultural matters, then why isn't he so?
My approach to the subject of water conservation and the useof water on farms does not follow that of the orthodox lines, and by inference, itcould be taken that I am critical of such methods. Of course this is so. Many ofthe orthodox approaches to agricultural education, and particularly those concerningwater on the farm, need criticism.
Now, water conservation and the use of water on farming andgrazing land is essentially agricultural. Education on the matter should be controlledagriculturally. But the present water authority, namely the civil engineer, willimmediately cry, "What do they know about the matter? This is a job for theengineer!"
Now, while it is agreed that the engineer comes into the farmwater problem, isn't it also apparent that the job of providing the dams has notbeen done. As recently as last year, 1957, and the latter half of 1956, despite fiveyears of abundant rainfall, drought again showed that we still need all the waterwhich we can collect and store. Thus it is not helping matters very much when officersand administrators connected with agriculture agree with the cry of the engineer.It must be patent, too, that the engineers cannot greatly assist until agriculturaliststhemselves fully appreciate all that is involved and lay the whole problem beforethe engineer, who may then be able to advise with practical designs. However, ifthe work is partly an engineering job and the Government engineers were widely experiencedin these very special matters, then of course the engineer should not be wastinghis valuable time assisting the few farmers, but should be teaching every officerof agriculture, so that they, in their direct contacts with the farmer, could assistthe thousand or ten thousand farmers.
The belief now that the engineer is the expert on these mattersis based on the fact of his training as a civil engineer, which includes a studyof earths (sands, clays, rocks, etc.) as structural materials for various works.He can design and build the giant dam, to him a relatively simple matter, since thatis part of his education and experience, but his training does not include any particularstudy or experience nor has he carried out experiments on what must seem to him suchan insignificant structure as merely a farm dam. Who can blame the engineer for beingunimpressed with the agriculturalist's present conception of the farm dam?
While I am willing to concede that in the earlier days muchattention was given to the big dam as a necessary public work, e.g., Burrinjuck andHume Dams and their irrigation areas, there was certainly no proper attention givento what would have been the alternative effect if properly located and designed farmirrigation dams had been provided over large areas of eastern Australia.
Full investigations along these lines would not have cost agreat deal of money, but if it had cost ten or twenty million pounds to get the answersit would have been little enough, since by now there would have been no problem ofdroughts because the effective conservation of the flood-type rains on the farmsand grazing lands would have more than counterbalanced the overwhelming cost of droughtand the high cost of floods. Furthermore, there could hardly have remained on agriculturalland the hazards, still very much with us, of serious outbreaks of fires. Were acomparison of size of the water storages made between big dam schemes and the totalityof farm dams, then it is worth saying that the conservation capacity of irrigationwater that would be available if 30,000 farms and grazing properties in N.S.W., eachone 1000 acres in area, were given the storage capacity they could hold, economicallystore and use profitably, then the amount of water would exceed that of the conservationcapacity of the Snowy Scheme (the Adaminaby Dam alone will hold eight to nine timesthe water of Sydney Harbour), plus Burrinjuck Dam and plus a few other big dams.If each farm could hold 300 acre feet of irrigation water storage capacity therewould be a combined capacity of nine million acre feet. Now, 300 acre feet is notan unreasonable figure for a thousand-acre area. For instance, it is much less thanthe capacity rate of "Nevallan" and "Yobarnie", and is not anymore than the extra water that will be conserved at "Pakby", near Bathurst,when this new property is developed, and is much less than the capacity of one ofthe new farm irrigation dams so far completed at "Kencarley", our new propertynear Orange. There are hundreds of millions of acres of agricultural land in Australiathat would have some profitable potential water storage capacity when compared withthe thirty million acres of the 30,000 N.S.W. farms mentioned only by way of illustration.
The farm irrigation dam is a worthwhile structure. As part ofthe agricultural conservation and use of water on the farm, the farm dam is as completelya specialised structure as any of the giant works that the engineer loves so well.To me it is just as important a job as the "big" dam. It could be evenmore important and it requires proper principles of precise location based on anagricultural appreciation of the factors of land shape and climate. It has correctbut specialised design based on the above factors and also on the depth of water,the foundation materials and the earth available for the wall, and on the particularuse to be made of the dam. It needs set construction methods, based on all the foregoingand on the type of equipment that will be used in its construction. (See alsoChapter XVIII and Pictorial Section )
The engineer well knows that earths, unlike iron, steel, brickor concrete are not stable structural materials, the behaviour of which can be accuratelypredicted in all circumstances, as can be done for these other materials he knowsso well. There is just no substitute for wide experience (particularly experimentalor trial and error experience) and mature judgment in this specialised agriculturalfield of farm water control. Agricultural knowledge is a first essential. The scaleddown model of the "big" dam, which is the civil engineer's usual offeringto the agriculturalist as a solution to the problem, is not nearly good enough. Thereis as much art and achievement in a fine watch as there is in a giant locomotive.The fine watch represents the farm dam, but who would employ the locomotive engineerto design and make the watch? Yet the farm dam situation is analogous. But most ofus are little people who love the colossus, the giant, the big job and the mammothspectacle. We no doubt have an inferiority complex engendered perhaps by the insignificanceof our life span against the evidence of great age in the geological forms with whichwe play. We are appalled by the immensity of the earth to our puny forms, and theinsignificant size of the earth in the vast reaches of outer space, and are overawedby the fantastic precision of atomic movements against the clumsy efforts of ourown hands. These feelings are related to the engineer's worship of the big job. Hefeels good if he can, just once, stand in the immensity of his own work. I know thisfeeling only too well.
This complex in many of us I may explain the sometimes ridiculousperpetuation of bigness in engineering, as, for example, the big dam for flood controlwhich does not control floods. These big dams never can control floods as effectivelyand cheaply as the many farm dams. This must soon be so obvious. However, works thatare next to useless and costing millions are not the fault of the engineer. Theyare built because most of us approve, and as taxpayers we all pay for them. It isrelatively easy for engineers to stampede on occasions even the wisest administratorsinto foolishness, if the foolishness is big enough.
There is, of course, this little complex which demands big things,but surely there is appreciation of the power of the little things, so many of them;for example, the power of catalytic change in the viruses or the forces in neuclei.Power and immense control comes from controlling the little things. Again, wateron the rampage in a flood is uncontrollable, yet it is easy to control the smallerquantities of water where it falls as rain before its accumulation gets out of control.The latest flood control structure is Glenbawn Dam, on the Upper Hunter River inNew South Wales, and it is now nearing completion. It is a multi-purpose dam. Ithas three "pools" with imaginary horizons; one is the lower or reservepool to regulate river flow downstream; two is the middle pool for power, and itis sufficient for the water supply for a thermal (coal) power station but nationallyinsignificant for water-generated electric power; and three is the top or flood controlpool. Although direct irrigation was a prime original purpose for constructing thisdam, the cost of water reticulation, pipelines, canals, channels and drains is sohigh that it is unlikely that this original purpose will ever be followed. Of course,Glenbawn Dam is not a solitary example of this particular problem of reticulationcost. There are other big undertakings, and huge volumes of stored water will becomeavailable each year for the next ten years, yet without means being provided forits use for irrigation purposes. The reticulation works to make use of the water,which is more often than not twice the cost of the big dam, is in practically allinstances several years behind the water supply.
Now, Glenbawn is a moderately large dam. The total height ofthe wall is 251 feet, the maximum depth of water at the wall is to be 245 feet, thewidth of the wall is 1800 feet at the base, and the length of the wall is 2700 feet;the quantity of earth and rock in the wall is 10,000,000 cubic yards. The total costof the dam is to be £15,000,000, and the total cost against yardage is thirtyshillings per cubic yard. Again, the total water storage capacity of Glenbawn Damis 293,000 acre feet from a catchment area of 500 square miles, equal to 320,000acres. The dam will require a total run-off of ten and a half inches from the wholeof its catchment to fill it from the empty condition. What is there to be said?
In the first place, one would have expected some public reaction.But there has been no wide public criticism directed against Glenbawn as a nationalworthwhile project and no criticism of its cost, or the cost per yard of wall, orthe cost of its water storage capacity, which will be about £50 per acre foot.The capacity of Glenbawn's theoretical flood pool in relation to its watershed areamakes it a much more efficient flood control dam than many others, and if the wholeof its capacity were used for flood control it would surely be a most effective floodcontrol dam as far as retaining water from its own catchment area is concerned. Iknow of none other that would approach it, though, of course, it is not a big damas big dams go. The cost problem can be further appraised.
The cost of Glenbawn Dam represents an expenditure of £47for each acre of its entire catchment area, or £47,000 for each one thousandacre farm or grazing property or forest area. This money does not improve any ofthe catchment area, while it renders useless some of the best land in the vicinityby covering it with water. The catchment area has to be improved in other ways withmore money if Glenbawn Dam is to be protected from siltation from its deterioratedcatchment.
It is appropriate here to examine the purposes and aims behindGlenbawn as a project and to determine alternatively how far these could be satisfiedby an agricultural development approach such as the Keyline Plan. Hence the firstrequirement of Glenbawn, and a laudable one, is to influence river flow by keepingthe flow more constant. Pump irrigation along the river is assisted and the aquifers,beds of water-bearing, sands and gravels which are important sources of ground waterand taken from wells for both agriculture and industry, are to be replenished. Tothe extent that Glenbawn may provide increased water in the river for pump irrigationfrom the river, it is providing for the costliest type of irrigation to those farmersaffected but at the lowest reticulation cost to the Government. However, this requirementof controlling river flow would be much better satisfied as an incidental to landdevelopment, as will be seen before the end of this book.
The second purpose of the Glenbawn scheme is the provision ofwater supply for a thermal power station. This could not be met as an incidentalin land improvement. The sole answer to this special problem is a dam located, designedand constructed for this special purpose. It is unlikely that the site selected forGlenbawn was entirely dictated by the power station water requirement, so a dam muchsmaller than Glenbawn and probably more suitably located for its special job, couldbe constructed at a very moderate cost.
The third purpose, flood control, is, in my opinion, not a logicalone. Water should be conserved for use, and especially on the Hunter. But the waterof Glenbawn is unlikely to be used for irrigation, other than from its effect onriver flow, as the reticulation cost would be too high. The dam conserves roughlyone foot of run-off from 300,000 acres; thus it could supply, disregarding evaporationand channel seepage losses, two feet of irrigation water to 150,000 acres at an extracost of, maybe, twice the dam cost, £30,000,000, making a total capital costof up to £45,000,000 for 150,000 irrigated acres, or a cost per acre of irrigatedland of £300, plus the original value of the land. Glenbawn would lose effectivenessas a flood control dam if used in this manner for irrigation. For these reasons,Glenbawn is apparently not the best place to conserve this water, and at such a costit may have been better to let the water go through to the ocean, although this wateris wanted badly for agricultural uses.
Unfortunately, however, these direct irrigation costs cannotbe verified now, but it is apparent that the whole matter is causing concern. Thedam is nearly completed but no major works for the reticulation of the water havestarted. At the moment an inter-departmental committee of enquiry is investigatingall these aspects of Glenbawn, and their findings, if published, should be of assistancein the assessment of the value of this major public work.
Glenbawn is only a suitable flood control dam if its entirecapacity is available for that purpose, i.e., if it is always emptied as soonas possible after a flood fills it. Yet it is a multi-purpose dam and is less effectivein flood control according to the volume of water retained in it. It could stillbe classed as upward of 50% flood control effective, and that, by comparison withothers, is very good.
The large multi-purpose dams for flood control and irrigationhave always seemed to me to be a partnership of two completely irreconcilable fellows.The irrigationist wants all the water held. The flood-threatened want the dam keptempty. Very naturally these dams, which are always costly, have an unhappy history.
The final question is, can the water that would normally causea damaging flood be conserved agriculturally in such a way that storage capacitywould be available to catch the next flood? The answer to this query is in the affirmativewhen the best water conservation plans are combined with the most effective irrigationmethods. And this is the meaning of Keyline.
The position is reviewed in this way:
The Keyline approach offers water conservation in differentbut special-purpose structures designed to conserve and use, but not to waste wateror allow water to waste. If it succeeds in this there is no flood problem. In orderto compare the different approaches it must be assumed that authority is equal. Ifone authority can do all the things necessary to build Glenbawn, then another musthave equal authority to take the alternative measures necessary in the catchmentarea of the big dam. However, the catchment area of Glenbawn contains some of thesteepest country in the Upper Hunter region, with over 60% of its catchment havingslopes exceeding 15 degrees. As the conservation of water by improved agricultureand in farm dams in such a region would be hard to determine, the comparative figuresbelow should be taken as applying to the more general class of country which is typicalof our agricultural land. Moreover, we are interested in all the land of the HunterValley and not only the relatively small watershed of the Glenbawn Dam.
Water conservation costs in Glenbawn are £50 per acre foot.The cost of the conservation capacity on the farms in a catchment area of Glenbawn'ssize would be less than half of this cost, and I judge this on my own experienceof many dams constructed to the designs in this book.
My costs of water conservation capacity on our farms range from£6 to under £50 per acre foot, disregarding purely experimental work. £6per acre foot is low, but I have seen many sites on other properties where it wouldbe even lower. The full capacity required then could be conserved generally at lessthan half the cost, and even this half provides or makes provision for an outletsystem in all the farm dams and also includes the irrigation drain for the reticulationof the water. Approximately 50% of the water capacity would be flow water not requiringpumping and would be available for irrigation in the lowest cost manner possible.This would be as much or more water than Glenbawn can provide for irrigation. Ofthe balance which would be pumped, most of the water could be employed also in flowmethods of irrigation. These methods are discussed in detail later.
Not only could there be a comparable capacity provided at lessthan half the cost, but included also there could be full irrigation provision forat least 50% of the water (more than Glenbawn flood pool) and partial irrigationprovision for the remainder. To accomplish this under the present set-up, Glenbawncosts would be more than doubled. Under the alternative agricultural scheme whichI advocate, the water is conserved on farms, on grazing land and forest land, indifferent kinds of dams each with a different and particular purpose. All the higherdams on each farming and grazing property would generally be used for irrigation.Within a week of rain they often could be profitably employed. The main method ofirrigation would be by 8- or 10-inch outlets from each dam and distributed by theKeyline flow system. The lowest dams or series of dams on each property would alsobe used for irrigation as soon as weather conditions dictated. Keyline irrigationis designed to take the maximum advantage from this water in as short a time as possible.The reservoirs or "middle" dams or series of dams would not be used forirrigation at this time. They are reservoirs supplying perhaps stock troughs or holdingwater in reserve. They would be used for irrigation after the water in the high andthe low storages had been used. Whenever heavy run-off rain occurred there alwayswould be storage capacity in at least both the high dams and the low dams. Also,in a planned design of use, no run-off rain water would waste from the land untilall dams were again filled.
There is also another great storage capacity available on thefarming and grazing properties of such a five-hundred-square-mile area. A Keylinesoil development programme would increase the general capacity of the soil to absorbat least two inches of additional rainfall, thus providing the lowest cost storageof all.
The money required for the project under this approach wouldnot be spent with little return, but would produce directly a quick and certain return.If advanced to the farmers and graziers it would be repaid quickly and be availablefor further work. There is big profit to be made from water control in agriculture.
I have said that Glenbawn compares more than favourably withother flood control dams. It can hold a so much greater proportion of run-off fromits own catchment that flood water from its catchment is, comparatively again, notlikely to add to flood flow. Now, Glenbawn's catchment is only 500 square miles,a small area 20 by 25 miles, and its effect in controlling or even mitigating a majorHunter River flood is not of any moment. Glenbawn is what is often classed as a "head-water"flood control dam, and such dams drain areas up to one thousand square miles. Nevertheless,many such dams as Glenbawn would be needed to affect a really big Hunter River flood.But if £15,000,000, as spent on Glenbawn, was made available as loan money tothe farmers and graziers for the development of their properties in the Hunter Valley,not only would the present shocking waste of water cease, but a lot of other wonderfulchanges would follow.
Another interesting cost comparison is that the cost of Glenbawnon a yardage of earth in the wall basis is at least eighteen times greater than myown recent costs of earth moving for farm dams.
The ratio of earth moved to water storage capacity in Glenbawnis in the order of one cubic yard of earth to forty-two cubic yards of water. Thebest ratio of any of my farm dams is one cubic yard of earth moved for a capacityof sixteen cubic yards of water. A more usual ratio for farm irrigation dams is oneto five or six. The higher the ratio, other things being equal, the lower the waterstorage cost. So, while Glenbawn's earth-water ratio is perhaps eight times morefavourable than many of the farm dams of Keyline, the earth-moving cost is eighteentimes higher, and, as is seen, provides a heavy balance in favour of agricultureand for keeping the flood rain where it falls.
I have no personal interest in and particularly no animositytowards Glenbawn as a project, or towards the men who approved it or those who designedand built it. It is selected here for discussion because it is new, its constructioncosts are today's costs and are known and real. Glenbawn also presents the factsfor this type of dam in a more favourable way (other than its high cost) than anyother dam of the type I know or have read about, including those in other countries.I know Glenbawn's background, climate and its conditions. We all recognise the HunterRiver flood hazard. Glenbawn Dam constitutes an excellent basis of comparison.
The Hunter River Flood Hazard.--It is not my purposeto minimise the Hunter River flood hazard. The dreadful loss of life, property andvaluable surface soil of which we were witnesses in 1956 and which had a world-wideadvertisement, has become such a holocaust that everyone is prompted to think interms of flood prevention. All that the average citizen has is the scheme propoundedby the Water Conservation Commission to build seven large dams, of which Glenbawnis by no means the largest, at the cost of countless millions, to do a job whichexperience now suggests they will not accomplish. If sufficient of the public thinkalong the lines of seven big dams for the Hunter River district the parliamentarianswill follow their lead and eventually build seven large dams. Who is likely to adviseagainst it? Not the engineer. He insists that flood control is a big problem, a taskonly for the engineer, and who is not impressed and convinced of the size of theproblem when watching a river on the rampage in a big flood. The official agriculturalist,then, what has he to say about the matter? Virtually nothing! He, most unfortunately,has been pushed out of the picture altogether, for even when a Government decidesto do something to assist farm water conservation, and wherein lie the solution tothese problems, the administration of the project is given to someone else. Whathas the official soil conservationist to tell the people? Only that, in certain instances,four to five and a half inches of heavy rain was held on the land of a farm or agrazing property where soil conservation methods and structures were used, but asthe big floods are caused by twice this amount of rain he thinks big flood controldams are necessary. In fairness to those all-too-few soil conservationists who thinkdifferently, I must record that some do believe that continuous flood rains up totwelve inches or more in 48 hours can be controlled, conserved, and later used onfarming and grazing properties. Some of these men in other countries wage a continuousfight to enlighten public opinion, but they have against them the policy which providesthe truly fantastic money allocated to the big works for engineering control.
Australian floods differ in the amount of rain which causesthe destructive flood. Total flood-period rain of twelve inches or less is the causeof most of our floods, but there are some small areas in the north along the easterlycoastline where rains up to twenty inches occur over a short period. From my ownexperience of these matters (in the increased conservation of water in the soil forthe development and improvement of soil, and in the location, design, constructionand use of many farm irrigation dams), I know that the control of flood rains upto twelve inches is only a matter of water conservation for profit where the lowestcost and the greatest advantage comes from the control of water where it falls, namely,on the farm lands, grazing properties and forest areas. In these instances thereis no flood problem but only the matter of preventing the illogical waste of neededwater. In those few areas where the floods involve rain of up to 24 inches over aflood-period it is still logical to aim at the economical conservation of the largestamount of water which may be later used profitably on the farms and on the grazinglands before considering any other approach. The last approach of all should be theflood control dams, and then they should be planned only as many smaller dams locatedin forest areas where the water could be flowed over the forest land. Forests, whenmanaged for the express purpose of disposing of excess water, can constitute thegreatest absorption capacity of any type of land, and may also provide profitableuse of the surplus water later in the trees themselves as a timber crop.
Big dams are justified only for purposes that require waterfor use for community or wide national advantage. Every city and town must, therefore,have an adequate and completely reliable water supply and so must plan storages ofa capacity suitable for the projected increased population of future years. The largehigh mountain storages for electric power generation have been generally a primefactor in the development of many countries, although today other sources of powerare often more economical and present technological development may tomorrow makesuch water-generated power completely uneconomical. Many fine large irrigation damsconserve water which cannot be used where it falls, for instance from snowfields,and these dams enable the establishment of flourishing irrigation districts in countrythat was virtually desert. Always, though, the bigness of the project is used toomuch as the most convincing measure of its success. While many large water schemesare justified by real success, the general large-scale irrigation project shouldalways be more critically examined against the cost of the irrigation land whichcan be produced from the many farm-scale projects. The glowing success stories inwords and pictures of some Government irrigation areas are not confirmed in the profitand loss account of the project, since the costs of irrigation are not directly assessedagainst the irrigated land. The capital costs, if disclosed against each acre ofirrigated land, would be found in some instances to be so high that only the tollof tax on all the people of a State allow the schemes to exist at all. However, myquarrel is not with the concept of the big dam as such but with the viewpoint thatfails to realise or even consider the comprehensive nature of, and the very widenational effect to be secured from, the many farm dam and irrigation projects.
At present we are in a position of serious lack of public thoughtas to what is correct in methods of water conservation. We must get our thinkingright first, otherwise we are likely to impose a dreadful legacy in the form of continuallywasting lands upon a beggared posterity. Education of public opinion on the basicimportance of agricultural land as the foundation of the nation's very existenceshould begin in the schools.
The problem of floods becomes social and national as well asscientific and preventative. Following every flood, we need to concentrate our moneyon repairing damage and our sympathy for the victims of the flood. We read that theflood damage in a certain river valley reached one million pounds recently. (Thedamage from one Hunter River flood was assessed at £1O,000,000.) Terrible! Ofcourse it is terrible, and it is worse because human lives were lost or jeopardised.
The real problem, however, is not the £1,000,000 of flooddamage but the sheer waste of more millions of pounds worth of water in a countrythat cannot afford the luxury of wasting any water.
Why is there not any real effort made to keep all our preciouswater? Because the job is too big for the nation? Because it requires a colossalamount of work and a hundred millions or more pounds, pounds which we do not have?On the contrary! The real job is not a series of big dams, while these will help,but simply thousands of farm dams which thousands of farmers are capable of makingand who could have finished them ere this had our agricultural authorities been determinedto retain overall control of matters affecting these wide aspects of water and landdevelopment.
There just must be a new approach to water. Can't we forgetabout the site for the giant dam on the river for a while and take a look at waterwhere it falls, since it is here our greatest source of wealth originates?
In the discussions on land shape it has been conclusively shownthat practically all land is contained in what I have called "primary land units".These units are the catchment areas of the primary valleys, and most of them flowto secondary valleys. These two types of valleys are the source of all flood water,but they also contain the most practical and economical sites for the storage ofthe precious water and as well contain in their catchment areas the land suitablefor the most profitable use of the water for irrigation. All the problems and answersof water and land are contained in these lesser units of land.
To get back to the present inadequate advice on agriculturalwater which is not given by agriculturalists only. Farm water conservation for irrigationon the farm is widely spoken of as supplemental irrigation and sometimes insuranceirrigation. Both could be more fittingly described as panic irrigation. The basisof too much of the official advice on supplemental irrigation is the complete convictionthat such irrigation on the farm does not generally pay, but that a farmer shouldhave a little irrigation land which he may use to supplement the general rain-onlynature of the farm. By having only a small area of irrigation land and managing thisefficiently he may then make it pay. In contrast to this and in circumstances wherethe production per acre from the type of farming is high enough, supplemental irrigationoften pays handsomely. In circumstances where it does not pay, then it becomes "insuranceirrigation". Like life assurance, there is no real profit in it for the assured,but it is a "good thing". It may save the farm in a drought, and many Australianfarmers were glad of their insurance-type irrigation projects in the drought of thelatter half of 1956 and all through 1957. It seems that the worst type of water schemeis better than no scheme at all. But what a dismal manner in which to regard suchvital matters as water and irrigation. Expert advice says that a farm dam for irrigationshould be planned against the minimum annual run-off of its catchment, so that thedam is sure to be filled each year. The water supply is therefore said to be reliable,but at the time of writing there has been no run-off for over eighteen months innearly all the areas where this advice is given. While this type of advice must bescrapped, it is not quite as ridiculous as it seems. Again, the real trouble goesa little deeper, namely, to the orthodox farm irrigation dam. This structure is builtusually in the valleys of the farm first--anywhere--and it frequently has land belowit which could be cheaply irrigated were there an outlet. But is has no large outletto enable water to flow from it and do at least part of its own distribution. Instead,the water has to be pumped up from the dam, and, in most instances, as the waterlevel lowers from use, the pump and engine follows the receding water down into themud of the dam. Invariably, such water is used for spray irrigation, which is generallythe most expensive type of irrigation, both as to initial cost and running expenses.Spray irrigation is one of the methods of irrigation and has its own particular provincesand uses as well as many variations, but the method of irrigation used should alwaysbe the one that best fits the circumstances. If the farm irrigation dam is to bethe basis for irrigation, then, if any dam is located wrongly or lacks design andis constructed badly without adequate outlet facilities what chances are there ofefficient irrigation. Usually, then, one dam and a small supplemental irrigationscheme is all the farmer can tolerate. The rest of his run-off water can waste away,since he cannot afford to collect and conserve it.
Before all the run-off water can be conserved plans for theeconomical use of the water are needed.
The idea that a large farm dam filled in a good season is afailure if it becomes empty by irrigation is not sound. Water has to be used. Juststoring water is not economical. There will be reserves of water elsewhere on thefarm as described earlier. Water is a means to an end, and when all the water ofa particular dam is used to this end, namely, the growing of crops or grasses, thedam is not a failure. The soil on which the water was used will be better; the cropsand fodder were produced and both can be conserved, and this is successful use ofwater. However, a dam or a series of dams remaining full because the water cannotbe used profitably is most assuredly plain failure.
A large farm storage that may fill only once in three yearscan be a fine investment for the farmer. The land below the water line of such adam when emptied. for irrigation is not waste land. When properly treated, as I havefound, it can be used then for special crops and should be the highest value landon the farm, with the single exception of irrigation paddocks.
It is so much simpler and more natural to turn a tap to getwater than pumping it. So the outlet through the wall and the turn-on valve are featuresnever neglected in the big community dam. Any design for a farm dam that does notinclude a means to this end of turning on the tap is deficient.
Further, it should be realised that water storage on farms hasmany factors much more favourable than those of the "big" dams. Foundationsare generally better, earth for walls is better, and hazards from heavy rains duringbuilding are negligible, while earth-moving costs are always very much lower.
There is this also to be said of water supply, the third factoron the Keyline scale. I believe that the overall planning techniques of Keyline providethe best possible methods for the location of farm dams and the best practical relationshipbetween the high, medium and low types of dam. From my experience, I feel confidentthat the designs of the dams presented in this book will completely satisfy the requirementsof the farmer and grazier, and that the construction methods and the various techniquesfor the use of the water will be so economical and profitable for the farmer thatthe ultimate aim of not wasting any water can logically be instituted as the bestpossible investment policy a farmer may make.
With Keyline planning and design the farmer and grazier willfind that he can conserve just about all the water that would now run to waste fromhis property. He will certainly carry more stock and he will need more watering pointsand paddocks. If he has not yet, he will soon realise that farming is big business.The capital value of all farms can be increased enormously, and landmen, becauseof the favourable taxation provisions as they apply to his business, are in a positionto finance the development of a very big capital asset returning good dividends andin the most advantageous conditions. And there is probably no country in the worldwhere these conditions are more favourable for him than they are in Australia.
Water cannot be dismissed with the conclusion of this briefchapter on water supply, which is the third factor on the Keyline scale of permanence.The whole question of the simple and direct factors of storage cost and economicaluse of irrigation water as between these farm dams and the big dams is capable ofa much wider comparison than I have illustrated. The largest and most economicalstorages in our vast Snowy Mountains Hydro Electric Authority scheme will not providewater for irrigation as cheaply per acre of irrigated land as many of the favourablylocated farm irrigation dams. Indeed, important as the scheme may be nationally,were it not for the electric power generating capacity involved, the whole Snowyscheme would not be even of secondary importance when compared to the work of providingfarm water storage and irrigation as effectively as is envisaged in these pages.
A comparison of the farm dam and the great Adaminaby Dam ofthe Snowy Mountains Authority may seem ridiculous on the face of the gigantic sizeof the one to the minute nature of the other. Yet the number of farm dams that areneeded throughout the agricultural lands and the capacity of water which they collectivelycould hold, would truly, as we have seen, be a huge scheme itself, albeit a schemecomposed of innumerable smaller units.
The bigness and urgency of the full development of the farmdam and irrigation project is not fully realised by merely appreciating that theywould have much more water storage capacity than all the big dams and would irrigatemuch more land extending over all the agricultural areas of the Commonwealth. Thereare these other important aspects. As always, there is the great question of transport.Water from any big scheme has to be transported great distances, which costs bothlarge sums of money and big water losses in channel seepage and by evaporation, butfrom the farm dam the transport of the water is necessary for the shortest of distances,often only a few feet and rarely more than 300 feet before it comes into practicaluse, thus saving enormously on reticulation costs and water losses. Again, the questionof transport becomes a powerful cost factor in the construction of these two typesof dams, the big storage and the farm irrigation dam. Earth for the constructionof farm dams usually is moved a distance of from a few feet to 200 feet, whereasfor the big dam the transport of selected material involves many miles of cartage,cartage which generally increases with the size of the dam. There would appear tobe a great asset in the concentrated nature of the water in the large dam, thoughthere is some considerable risk of collapse, especially in war time, but with theinnumerable small storages spread over the whole country there is presented no majorrisk.
Then there is the question of finance. In the big project thereis never any expectation that the big outlay will ever be returned quickly, whilewith the farm storage project it is profitable in the way the landman and ordinarypeople understand profits. What is at stake? An amount of money is spent to starta farm irrigation project. The dam is constructed quickly in a few days or a weekor two, the dam is successful, irrigation is profitable, and the capital cost ofthe work, be it loan money or farmer's capital, is paid back in a very short time.And there is in Australia not even any associated tax problem. The work is paid forfrom profits before the farmer's income is determined for tax assessment.
There is no doubt that we need all the water that we can conserveand that we need it where we can make best use of it, and this will always be onthe farm and grazing lands of the Commonwealth.
As has been said, the undertaking is a vast one, but any greatundertaking is made up of many parts as well as many people and much money, and todo the work quickly the undertaking must pay for itself as the work proceeds. Payingfor itself simply means that a great number of people have to make a lot of moneyout of it, but as the people also have to pay for the work, then the scheme mustbe productive in the shortest time. If, as farm water conservation proceeds, thesmaller parts of the whole scheme can be complete in themselves and be producersof good returns in a year or so, then the largest of projects can be undertaken withthe minimum amount of money. As far as Government finance is concerned, no worksapproaching in size or importance that of the provision of adequate farm water supplycould be undertaken so economically. A nationwide development worth literally thousandsof millions of pounds could be projected and commenced with a comparatively smallsum of money, a sum no more than has been considered lavish in the past for infinitelylesser public work, and which has been deemed to be well within our financial capacity.
The big dam for irrigation and the farm size project for irrigationare both necessary for the realistic development of this country, but one aspectof this development, the farm project, has been grossly neglected.
The true relative importance of the two water schemes, the bigdam irrigation scheme and the farm-scale water project, may have been difficult forthe reader to realise, yet I am hopeful, by the time I have reached the last referenceto water, he will be in full agreement with me on the importance of farm water conservation,not only on account of its great value to the farmers and graziers, but because ofits completely dominating influence on all national aspects of land use and watercontrol.