IRRIGATION IN CENTRAL OTAGO.

Otago Witness, Issue 2870, 17 March 1909, Page 27

IRRIGATION IN CENTRAL OTAGO.

-i. m ' • OFFICIAL INSPECTION. GOVERNMENT -OFFICERS' REPORT. INTERESTING AND VALUABLE ; INFORMATION. WELLINGTON, March 15. The Government has been giving anxious consideration to the irrigation of Central Otago, and with a view to ascertaining the facts and obtaining a "reliable opinion, asked for a report through the director of experimental farms. That inspection was made by Mr Bruce (inspector in charge of the Otago district), who was accompanied by Mr Dobson (in cnarg* ol irrigation surveys in Central Otago), and ■who collaborated with Mr Bruce in the •preparation of his report. The report is as follows : — In response to your memorandum of the ' 4th' of September requesting, me to locate the areas, of agricultural land in Central Otago could be profitably irrigated, "I Ijave now the' honour to submit the following report Fully recognising the importance of irrigation, .not only to the arid districts directly, but ultimately to I The > State, and the responsibility unreservedly, entrusted to my individual judgment, I decided to approach . this sub--jeefc purely, from a commercial standpoint, it l>eing no part of my duty either to extol or decry the land, beyond concisely etaiing the qualities pertaining to the several blocks inspected. I was accom- . panied throughout the inspection by Mr J. H. . Dobson, -engineer in charge of the irrigation surveys in Central Otago, who • rendered valuable assistance, not only in the field, but by computing the areas located by ma, in addition to defining and • illustrating same on the map which accom- 1 panics this. In support of the opinions expressed, samples of soil- have been freely taken and submitted to the department's chief chemist (Mr B. C. Aston). EARNSCLEUGH BLOCK. Earnscleugh Flat is situated- on the right bank . of the Clutha River, and extends from opposite Clyde to near Alexandra, containing about 5400 acres. It is composed entirely of river gravels, covered with a-' sheet of soil varying from nothing 1. to several feet in depth Of this there are about 2900 aores fit for irrigation, the balance being shingle, and in many places destitute of soil. There is abudant evidence that water would percolate rapidly through this formation, without producing ■any appreciable benefit, even were it applied in .-enormous quantities. Where top soil- is' present,, it' is so very" friable that on the, application of water it at first " readilyf transforms into a puddle/ with the result that* ultimately stunted rushes make their- : appearance, '. instead "of luxuriant vegetation". "' On .the area, referred to as being suitable for irrigation the soils -are fine decomposed schist, with a fair admixture of humus, and respond well to cultivation. A .portion ol this land (about 700 acres) has been irrigated for years, and is | capable of better cultivation than obtains at present. Blackman's Gully. — rhis is a beautifullysituated gully for fruit-growing, extending from Earnscleugh Flat, which is about 600 ft above the sea level, to an altitude of ' possibly 1600 ft. It consists of isolated j basins, intersected by rocky ridges, and i contains possibly 500 acres of fine sandy | loam, lying with a northerly aspect, and well sheltered. Although this .beautiful valley would no doubt respond well to irrigation, its irregular surface configuration a,nd steepness, would necessitate the exercise of great care in the application of .water. To obviate undue seepage to the detriment of the lower basins, hand cultivation would have to be largely depended upon, much of the land being too steep for 'the use of modern appliances. This would be likely to make hill orchards prohibitive under the present conditions of labour,, even were a sufficient supply of - water available at a nominal cost, .which in that case it would not give. There are also several. small areas in the vicinity of Conroy's Gully similarly situated, and to wiioh the above' conditions would apply. This country ie all inoluded in the. Ernsoleugh pastoral runs, the lease of which does, not -expire fox some 13 yeare. At Bald Bill Flat -there "is an area of about-\I7OO acres, which could be profitably irrigated 1 were a suffioient supply of water obtainable. -CLYDE BLOCK -H. from the Clyde commonage along ihe foot of the Duostan Range to Chatto Creek, reaching to "the Manuherikia Rdv-er, «nd thenoe along _ the- Clutha" River i to <21yde, of which area approximately 3000 j aores are fit for irrigation. There is a helt-r of fertile soil from Clyde to Chatro Creek, i but. owing to its irregular surface form, and ' to being intersected with outcrops of gravel ( it cannot be described as lending iteelf | well for irrigation, and I am of opinion < that there is sufficient natural seepage from the mountain to make, farming profitable, especially in growing winter f-eed for eiock. There is a small expans® of fertile soil below Moutere station, another at Spring Vale, and a third towards the Manuherikia River, bwt of no appreciable extent. Clyde Raccourse. — I am informed that , this lam* was reported upon some years ago by the Department's pomo'.oqists as being suitable for fruit culture, provided a sufficient supply of wk« could bs obtained. I eons-dor thi^ en ideal field for e?iperi- i mental work, lip-inc; quite clcse to Clyde railway station. It contains about 100 aores more or less of fairly good land, somewhat deficient in humus, but admirably adapted for experimental irrigation. Taken in conjunction with the adjoining la.nd, which is considerably lighter, being- similar to ether j areas in Central Otago, notably the Groin - , well Flat, it should assist in determining . ■whether irrigation could be profitably 1 adopted or not. I should recommend for ; your consideration the practicability of ob- . taining a sufficient waiter supply for experimental .purposes on this block. i Adjoining the Clyde racecourse there is , a holdi-ng of some 60 acres, which I am \ informed has been under- irrigation for ' • about 40. years. On the best of the soil • the results appear to have been highly i satisfactory, but it is observable thait on • Teaching the lighter soil the waiter dis- j appears. -Possibly experimental work may ; demonstrate that the cultivation and ploughing down of leguminous crops wou'd Aid nitrification, and thus extend the irri- | gable area.

The balance of the Clyde block is ridgy tableland composed of high level _ Band, etone, gravel lying over clay, varying in depth from a few inches to possibly 100 feet or more. There is direct evidence that this country is absolutely unsuitable for irrigation. It puddles readily where there is any topsoil, grows rushes, and is co porous that it absorbs an unlimited quantity of water. This is clearly demonstrated on M'Arthur's fa.rm, and it is aleo proved by- tihe seepage from the Alexandra water race. GALLOWAY FLAT. Where good soil from the higher levels has been deposited round the ends of the gullies, as is commonly the case in districts examined by me. irrigation is highly remunerative, but immediately the water extends beyond the limits of *he good coil, it disappears into the shingle. Irrigation has been carried on here for years, but notwithstanding the strenuous exertions of Mr Alexander, general manager of Galloway station", arided by a liberal water supply, the aTea that is capable of being irrigated does not increase. TIGEP. HILL, LAUDER BLOCK. This area extends from Chatto Creek along the foot of, the Dunstan Range to Dunstan Creek near St. Bathans, and thence along the Manuherikia River to Chatto Creek. The fertile belt referred to as extending from Clyde along the Moutere faces continues along the whole length of the foothills' to Dunstan- Creek, varying in width from one to two miles or more. Of this a considerable area, is capable of cultivation without irrigation. This block contains a large area of land, approximately 35,000 acres, 'fit for irrigation, extend : m? from a mile above Chatto Creek Railway Station to Cambrians, facing the Manuherikia River and Dunetan Creek. The greater portion of this area is good agri1 cultural land, composed of mica schist soil with rich humus, and is admirably adapted for irrigation. About 4000 acres of ' this block are already irrigated, particularly ! 6o from below Tinkers to near the railway line at Spottis Creek and from Dryfcread to the Main road at Lauder. The benefits of irrigation where applied with discretion are certainly phenomenal, while on the other hand "harmful results' are noticeable from continual flooding and negligence. There is a large area of flat land between Matakanui and Chatto Creek, commonly known as the Matakanui Flat, in addition to several table lands situated between t Thomson's and Lauder Creeks, which '-'although apparently lending themseivos well for irrigation, are unsuitable because of the absence of soil in some places and the poverty of the soil in other places, and the sub-soil being of a cementy, sandy gravel. Mr John Wilson, of Lauder, who has had - much practical experience of irrigation, has '^lately constructed a race to one of these taole lands with the intention of liberating the sludge from Tinker's diggings for experimental purposes. The result of this experiment should be most interesting, inasmuch as it will demonstrate the effect of an abundant water supply on poor land where the shingle is sufficiently impervious to permit the water to distribute itself before disappearing under the surface | The sludge from Tinker's contains a con1 siderable amount of decomposed schist and humus, .and should, unlike' most tail race deposits, have a beneficial effect. Should this experiment prove a success, similar treatment could be applied to the Matakanui Flat. At the same time the fact ■ must not be overlooked that the lrrieraI tion of this class of land is only practicable j- where an abundant supply of sludge water ! can be obtained at a nominal cost, as at beet such land is -only fit for grazing purposes. > IDA VALLEY, BLOCK IV. This block commences at the Poolburn Gorge and extends along the foot of Ruggody Ridge to its junction with Rou>jh Ridge, which it follows to above the Oturehua Railway Station, thence it, stretches to the mouth of the Idaburn Gorge, along the Naseby-St. Bathans road to Hill's Creek, following the foot of the Blackstone Hills Range to Poolburn Gorge, and comprising approximately 60,330 acres, of which area, about 52,500 acres are fit for irrigation. Almost the whole of the land on "the southern side of the railway line is admirably adapted fon irrigation, a very large proportion, being first-class agricultural land, which would undoubtedly become highly productive on the , application of water. There is conclusive evidence that even the lighter soils here would respond well to irrigation, in some places to an almost incredible degree. ■ The local Irrigation Committee, composed exclusive-lv of bona fide farmers, is so convinced of the suitability of its land for irrigation and the benefits to be derived therefrom that it has ,6ubmitted. through its secretary (Mr A. Armstrong), a proposal, j signec. by 58 farmers in Ida Valley, offer'ng i-sums varying from 19s to £2 a week per I sluice head of water for about 100 heads , for six months yearly. With the better cultivation and the closer settlement which 1 would consequently follow, no doubt a | higher price could be paid for the water, of which a much larger quantity would in time be required, while the value of the land would be proportionately enhanced. On the northern side of the railway line the land is somewhat irregular, portions of it being shingle drift from the adjoining mountain with a. shallow covering of top foil of inferior quality The Hill's Creole <n:d is ut ' rather a high altitude (about 2000 ft) above the sea level, and inclined to bo col-t! end sour. Along the foot of the Bkiekotone Hill Ran go and extending towards Ida Valley Railway Station th« foil im proves ' and should no doubt benefit from irrigation. The following is a statement .<-ho^i:ijr the amount of irritable land in the Ma, Valley district, with the names of holders.

the quaitity of water each will take, and amount per head they are willing to pay: —

The-re is a considerable area (approximately 4330 acres) of highly fertile land on either side of the Upper Poolburn on which irrigation would ba unnecessary, as it derives sufficient moisture from the laterail "subterranean. — (See page from the Poolburn and Dunsdale Creek.) I consider Ida Valley an ideal field for irrigi-ation, and can with confidence " recommend the adoption of any scheme whereby water could be obtained, even at a very considerable expenditure, so lon.g as the land was not loaded bevo'nd its producing power. ROXBURGH BLOCK. This, a iimited area of fertile land, ■ situated towards the southern end of the arid region, lies ohiey on the right bank of the Ciutha River, with a northerly aspect, sloping beautifully from the hill foot to the river. The soil is of excellent quality, and has proved eminently suitable for fruit-growing. The orchards there are evidently managed with skill and ability, and most of them a-re already provided with water from the mountain stcreams. Some of the owners have not so far found it necessary to irrigate this land, and those "interviewed by me all aigree that if judig-rn-ent is not exercised in the application of water, the result is liable to be disastrous, both to soil and fruit. CROMWELL BLOCK. From the Karoarau Gorge this follows tha foothills to Lowburn, thence extends along the Olutha River to its junction with the Kawarau, whence it stretches to the gorge of that river. There is a narrow belt of highly fertile soil extending along thx> foothills, containing about 2870 acres suitable for irrigation, and of this area about 1000 sores are already irrigated. The soil is decomposed mica schist, intermixed with rich loam, possessing an extraordinary power of endurance tinder cultivation. One farmer, (Mr Jan*ps Ritchie) informed me that a portion of hie land bad* produced 17 I successive crops of oate without manure, I and that there waf still no signs of its proI ductivencss "abating, the last crop yielding ! over 60 bushels per acre. His method of j cultivation has bsen to crop and fallow 1 alternately for a period extending over 35 \«U'6. There can lie no doubt as to the benefits of discreet irrigation on this class of land, which, without water, would be practically valueless. As frequently happens, the fertile soil terminates abruptly a short distance from the fcot of the range, and here this is I conspicuously the caee. Immediately joinI ing this land lies the Cromwell fiat, which embraces approximately 4700 acres of ex- | trembly disappointing country. About half I of this area and what would otherwise ! l,a.\e V?cn the best portion of it is now | co\ered with drifting ?iand. The greater ] poition of the balance is very flat, with j a flight top soil of poor quality, over a bhin-gle bed of great depth. The soil iml proves towards the racecourse, but -even I here it is, intci^ccted by holts of shingle, which would absorb enormous quantities I of water, possibly without any appreciable benefit for a long period Some years ago the irrigation of a portion of this flat was attempted by private enterprise at a very considerable cost, a,nd from indications ptill visible it had been directed with much skill. The settler who so courageously attempted to convert this bariyn waste into a fertile plain wa=, so he informed me, c<rnpelj,sd to abandon ihe scheme, and ultimately to pay a small cum to another porscn to be relieved of his interest in ihe property. He is still, however, of the opinion that were the whole of the Roaring Mcc River diverted to Cromwell Flat it would in time restore vegetation ovor a Urge portion of t. It stems to n.e tha»t the j only feasible method of dealing with this flat' is to proilde water under pressure, to bo applied by hese directly to the planr-s. Such a scheme, however, could only he adopted in small orchards, and even then iie suf-cess would be doubtful.

MOUNT PISA BLOCK. From Lowburn this follows the foothills to Luggate, thence extending along that stream to its junction with the Olutha River. Between Lowburn and Mount Pis^ Homestead there are several 6mall areas of first class soil. In sonio instances as muolx a? 200 acres are to bo found in one continual stretch with imimportent- shingle beds intervening. This "is exceptional, and ge-nerally, owing to the presence of shingle, iwssibly not more than 20 per cent, of the aica marked on the map could be conskisred suitable fcr profitable irrigation. It is worthy of note, however, that on this block the soil, even where sparsely distributed over or through the shingle, is fine decomposed misca schist, responding readily to water, but unfortunately the absorption is so great, apart from the close proximity to the river, which is at a much lower level, that it would be impossible to saturate the lower strata even were the water supply unlimited. The several areas now irrigated (about 450 acres) are most ailuring, dotted as they are throug.h this arid valley, but, as already stated, there is evidence that rapid percolation would render' any comprehensive scheme of irrigation impracticable. Between Mount Pisa Homestead and Luggate several small areas have been irrigated" with some success where the soil is or less suitable, but the -<^nditions generally are not conducive to any elaborate scheme of irrigation. The "area of „ irrigable land in this block is estimated approximately at 4740 acres. LUGGATE-GLENDHU BLOCK. From Luggate Stream this follows thehill foot by Mount Barker to Glendhu, thence extending along the east side ol Lake Wanaka to the outlet of the Clutha River. This block may be described as purely pastoral land, the soil generally being of poor quality, and excepting small areas at Luggate and Mount Barker there is practically no land fit for extensive cultivation. Of the areas marked on the map as suitable for irrigation (approximately 2900 acres), about 600 acres are already being so treated ; but irrigation on this class of land can only be made profitable when an abundant supply of water is obtainable at a nominal cost. HAWEA BLOCK. From - the outlet of the Clutha River this block follows the foothills to Lake Hawea, thence extending along the hillfoot on the northern -side of the Hawea Settlement to Sandy Point; The areas marked on the map as being suitable for irrigation contain approximately 6870 acres, the greater portion being the Hawea Flat, which possesses a rich soil, eminently suitable for high-class farming by judicious 1 cultivation. Excellent results are already being obtained without' the, ajd of irrigation. At the same time there can -be no? doubt that this fertile plain could, be rendered safer and more profitable if water were obtainable when required. The. balance of this -block 'is poor pastoral country, much of it being river shingle almost destitute of soil. " . TARRAS BLOCK. This block includes the Lindis Valley, stretching from Sandy Point to the head of the Lindis Downs, near Grumbling Gully, thence extending along the foothills of the Dunstan Range below the Lowburn Punt. It contains approximately 25,740 acres fit for irrigation. This land presents leaturcs seldom met with, inasmuch as it embraces at least four distinct conditions — (a) Land of quality and texture fit for, irrigation and so situated as to be commanded by. available water; (4) land fit for irrigation \vhich cannot be. commanded by water ; (c) land suitable for agriculture -without irrigation; (d) land unfit for irrigation under all conditions. The belt of land suitable for irrigation, situated on the left bank of the Lindis River, is worthy of special mention, extending as it does for a distance of about 13 miles between the northern slopes 'of the Dunstan Range and the Lindis River. It would, if provided with sufficient water for irrigation, materially assist settlement, and at the same time assure the prosperity of a number of small grazing runs when the country comes to be subdivided. GIBBSTON BLOCK. This small expanse is situated on the right bank of the Kawarau River, about midway between Cromwell and Arrowtown, and contains approximately 1120 acres of land fit for irrigation, of which some 200 acres are already irrigated. The soil and contour o* -the ground are especially good, and the benefits of skilful irrigation a-re even now clearly demonstrated^ There is also a small aera of good land at Waitiri, but from there towards the Cromwell Gorge. the small, river flats, which were formerly covered with rich soil, have been destroyed by gold mining. MANIOTOTO BLOCK. This plain extends from the laieri Gorge at Linburn to Kyeburn, and contains approximately 266 square miles. Of this a-rea some 108,700 acres are situated on the south-western side of the railway line, and of these about 87,000 aores are fit for irrigation. The balance comprises — (a) Land which cannot be commanded by water, (b) land with irregular surface configuration, and (c) isolated shingle belts. The soil is decomposed mica schist, overlying fine gravel intermixed with soil and clay. The greater portion of this land is deficient in humus, and where it nab not been cultivated both the soil a-nd the subsoil are extremely hard of cultivation, and the ploughing down of leguminous crops, aided by a liberal supply of water, should materially assist in remedying this. Where under cultivation, the soil of th» Maniototo Plain absorbs and responds readily to moisture, and there is conclusive evidence that when irrigated with discretion this large area is capable of being transformed into' a. highly fertile expanse eminently adapted for graingrowing and the raising and fattening of stock. On the north-eastern side of the railway line the soil and its surface configuration are very irregular, and may be described as pastoral country containing isolated areas of fairly good agricultural land suitable for mixed farming without irrigation. Over the major portion of this area the under strata is shingle drift from the Mount Ida Range, intersected with gullie3 and flats, over which there is but a thin covering of inferior soil. About Wedderburn, however, there are approximately 3830 acres in one block, and several smaller patches in oiher places, where irrigation might bo made profitable, but owing to the smallness of those blocks and their scattered positions, the cost of pro-

curing water would be too great to H remunerative. SUMMARY. While engaged inspecting the varioy* blocks of country reported upon I came in. contaot with the members of several irriga« tion leagues, and many other persons simi< larly interested, and a good opportunity was. thus afforded of noting the general opinion on the important, subject of irrigation, which, epitomised, is " Give us water for irrigation and the future of Central Otago , is aa-surred." Where the soil is suitable aad l the natural conditions favourable I am o? the opinion.^ that irrigation properly applied will probably do all that is claimedfor it. In the course of my inspection I could not help noting that some of the es=sentials of good farming are in many instances conspicuously absent. In Central Otago, with or without irrigation, the average farmer has much to learn, or &i anyrate to put into .practice, before the best results can be obtained from the soil. The most casual observer, cannot but note the lack of thoroughness generally prevalent in the methods of agriculture. In many cases nothing approaching a reasonable attempt is made to pulverise the soil, the. surface Being left uneven and rough, thuf ' permitting the moisture to esca-tfe instead, of", being retained in the soil to support vegetation as it .would were more thorough cultivation adopted. In several instances where" irrigation has been adopted the re« suits are harmful, in so far as through^ Jioglect tp premoye surplus water by drain-... 1 age the soil' is becoming sour, and unless^ this is remedied the land will become si, barren moorland of rushes, instead of thriv< ing fields of grain or profitable orchards Scarcity of labour has doubtless much ta do with this, although negligence on the part of some owners is noticeable. It i« not unusual to find a small family attempting alike the cultivation, stock work, and every duty pertaining to a large holding containing perhaps several hundred acres of good agricultural land without the ad of any hired labour, which, even were it desired, is not obtainable. Under such conditions irrigation could not be rendered profitable. The question naturally arise< whether with land capable of beingr mad« • highly fertile, but now lying practically idle, the State should not encourage th* adoption of more modern "methods 'of agriculture, including irrigation, by instituting! a scries of field experiments in -Central Otago, a' large area of which can only attain its. full productiveness by the aid of irrigation. On the other hand it must be emphasised that irrigation can only become^ profitable . by thorough cultivation, involving the employment of much labour directed with skill and intelligence. Any scheme to £rovide an adequate water supply for a trge area must necessarily be expensive, entailing a fairly substantial price ioi water, -apart from the cost of distribution to the farmer. I am informed by several trustworthy persons of long experience that the ' cost' of distributing water, attending to water races, etc., is not less than 10s pej« acre yearly over the atrea treated. Add to this ajnount, say, 'dßl^ger -week for each •sluice head of water lised. And. assuming? - that a head 'of water under favourable conditions "will irrigate 100 acres, the' land becomes burdened to the extent of £1 per acre annually. In my opinion irrigation! in this country can only be adopted with advantage where the land is sufficiently" fertile to produce the best results, anc? where the occupier is prepared to pur&ue a regular system of cultivation. The irrigation of purely pastoral country can only bo rendered remunerative when an unlimited suppk- of water is obtainable at a low cost, a condition' which is seldom likely to pertain to' the arid regions of CentraJ Otago. (Signed) J. L. BRrmn, - j Dunedin, January 22, 1909.APPENDIX D. Total area fit for irrigation after malr ing deductions for land already irrigated/ Acres. ■Block I 4,400 Block II 3,000 Block 111 31,000 Block IV 52,500 Block V, Roxburgh — Block VI-, 1,870 Block VII 4,280 Block VIII 2,330 Block IX 6,870 Blook X 25,740 ' Block XI 920 Block XII, Maniototo 89,000 Total 221,920

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