IDA VALLEY

Evening Star, Issue 20023, 14 November 1928, Page 8

IDA VALLEY

FIRST IRRIGATION SCHEIE MAKORBURN DAM STORACF SUPPLIES BELOW ESTIMATES Pressure on our space duo to Hie election campaign has interrupted the scries of extracts' from the Irrigation Committee’s report on individual schemes in Central Otago. To-day we resume the series with the reports on Ida Valley and Galloway, both served by the Manorburn Dam. SUIT LIES CAUSE ANXIETY. DRAINAGE NOT URGENT. This scheme was the first undertaken by the Stale, and from a 1 arming point of view lias proved very successful. The land in the main differs from that, of other schemes, being heavier and requiring lens water. This was evidently realised at the inception ot the scheme, as tho allocution of water was ou the basis of one cusec to 200 acres, against olio cusec io toll acres ou most of tho other .schemes. Even this amount of water in some cases appears lobe more than sufficient, some of the irrigators not using their lull quota. The water is obtained from a dam in tbo Manorburn catchment, and is supplemented by various small creeks along the races. At present some 11,300 acres are served in Ida Valley, but portion of the water is diverted over Low’s Saddle to irrigate about 2,500 acres on Galloway, where the laud is lighter and requires a greater amount of water.

Complete records Imvc been kept of tho water available lor the past ten years, and it. is evident from these that careful observation of the supply will require to be’maintained. During last season—a particularly dry one—tile draw-off from the dam exceeded the net annual gain, in the previous season there was actually less water taken from the dam than flic annual gain. The reverse would have been the case had the Ida Valley irrigators taken their full quota. Tlic reason for this shortage appears to 1.0 that the gain from creeks was originally over-esti-mated. 'this probably is easily accounted for by the absence of records. The experience of tlm past few years lias shown that the supply from these creeks has not reached expectations; the flow, from all accounts, exists_ in the early part of the season, hut diminishes during the summer mouths. If some of this early water could be conserved there would bo very little cause for anxiety, but under present circumstances curtailment of supplies would be necessary if two or three dry years in succession were experienced. Jt is understood that reports on tho position have been submitted by the local engineer of the Public Works Department. Tho scheme covers two areas—i.c., (1) tho original Ida Valley scheme, under which'the settlers were enarged IQs per acre per annum, and (2) the area 'Served at a later date, over which a, 15s rate is charged. No grievances m regard to water rate were heard from those on the first area, but those on tho second area fgid that they are being overcharged, and requested, a reduction.

Most of the land throughout is of fair qualify, and appears to warrant tho maximum charge being: levied. The committee therefore considers that this area should lie charged at tho rate of 11s per acre per annum, as against tho 15s rate now being charged. It is not suggested that tire present rate of LOs per acre on the original scheme ho increased', as current agreements limit tho charge to this figure. These original irrigators were fortunate in securing agreements at an early date and at a low rate. The committee is not disposed on that account to reduce tho charge being made to the irrigators on the lower portion of the scheme to a like amount simply because tho irrigators in tho first section secured an earlier and more favourable agreement. Wore such agreements nut in existence, the committee would in all probability recommend a flat rate of 11s per acre over both areas.

ft whs represented, by tbc settlors on Uio lower end Unit iimdequato drainage through the middle of the valley was causing damage, this being mainly duo to the effect of irrigation water. It is apparent that steps will have to bo taken to remedy llio present position of inadequate drainage, and it is evident that this necessity was recognised when the original estimate of Ida Valley was prepared, provision for drainage being included. While it is_ realised that a portion of Ida Valley is suffering from, the effect of excessive irrigation water and lack of drainage, the committee does not feel justified in making a definite recommendation in regard to straightening the Foolburn to allow of freer exit of drainage water. The area of land visibly affected at tbc time of inspection was found tobe 270 acres. The cost of straightening the Foolburn and maintaining it in good order would._ in the committee’s opinion, bo excessive when viewed in relation to the area likely to benefit thereby. A considerable amount of good would result if a_ moderate sum were expended in clearing some of the existing.obstructions in the creek. In i-lio caso of damage resulting to land adjacent to the creek the Advisory Hoard should bo asked to decide what adjustments should bo made. Many of the apparent ills of irrigation in the valley, a.s evinced by the intrusion of rushes in the country flanking the slopes, cannot be attributed to a rise in ground water caused by a blockage of the Foolburn. This state of affairs can bo largely accounted for bv the retentive nature of _iho subsoil, which brings the irrigation water to the surface, combined with a too lavish distribution of water over certain sections.

11l view of ilic class of land under irrigation in Ida Valley, it is recommended' that iho present allocation ol water—namely, one cuscc; to 20U acres —be adhered" to. Thera is ample evidence to show that this allocation oi water is sufficient to meet the needs of iho different farms under irrigation, and the committee does not feel Justified in recommending any alteration in this respect. Tho committee recommends that, in regard to those scheme where water shortage is likely to occur, and where individual settlers hold largo areas ol irrigated land, negotiations be initiated with tho object of reducing the areas signed for, thus placing the schemes on a sounder footing in so far as water is concerned. GALLOWAY SCHEME MORE WATER NEEDED. This scheme is situated on the left hank of tho Manuherikia River, a. lew miles to tho north-cast of tho town of Alexandra, and derives its supply at water from tho same source as Ida Valiev—viz., tho Alan orb urn Dam. .-‘The present allocation of water is one cusec to 150 acres (or 24in poi acre) over most of the area, as against Ida Valley’s one cusec to 200 acres (or 1 gin .per acre). The land is much lightfer, and requires a greater quantity of water, more particularly on tho Hat nravclly lauds, where, hi tho opinion ol tho committee, even 24iu is insufficient, especially in the early stages ot development. The settlers have been purchasing a considerable amount of extra water, amounting last season to 1,313 dav heads, or 57 i per cent, of the ordinary supply. Even allowing for j. fair proportion of this being wasted, which is inevitable in the early stages ol irrigation development, when the settlers arc not sufficiently experienced in the use of water, it is evident that this

land could profitably use more water. As, however, the supply is limited under present conditions, as pointed put in tho portion of tiie report dealing with Ida Valley, extra water oyer and above the recommended allocation cannot continue to ho given to this area during dry seasons unless more water is made available. Tho area covered by irrigation agreements is 2.G71 acres, portion of which is on tho slopes of the Crawford Range and Olrig Terraco, where tho settlers are sheep farming, but on tho flats dairy farming predominates. On this area, once primarily confined to the grazing of sheep, there has been a< marked transition from that typo of land utilisation to dairy farming. This change in farming methods can bo largely attributed to the fact that tho Government established on Galloway Flat an irrigation demonstration farm, tho activities of which are mainly devoted to tho development of dairy farming in the district, the position being to-day that practically every farm on Galloway Flat has adopted dairying. Tliis experimental farm has been _of value to tho committc*; in determining the amount of water required on the Galloway lands, and the value thereto of such water. Tho farm appeared to the committee to bo administered on sound linos, and must certainly be of great benefit to tho farmers in the district. Tho soils of- Galloway are of a variable nature. Towards the foothills of tho Raggedy Range heavy types are to bo found, these lending themselves ideally to tho production of luxuriant crops. Towards the Muuuherikia River the soils are lighter and of a very porous nature, necessitating as can be expected, a greater supply of water than, is at present allocated, and requiring more frequent irrigations than necessary on the heavier soil types. Practical! v adjacent to tho river and' on « level with it are areas which do not require irrigation, the ground level of water being sufficiently near to tho surface. On this area certain features in regard to drainage and alkali will in all probability have to bo studied at no distant date. Galloway represents a section of an irrigation scheme which is in a moderately advanced state of development. The fanners on this area appear to bo working on sound principles, and their experience lias been of material value in the formation of this committee’s views. The following recommendations are made;— rn That the present allocfitiou of Vi —lu&iiei.y, one cU&gu 130 acres—should, in so far as is consistent with the available water supply, lie altered to the allocations recommended in the schedules for each holding. In regard to such allocations, it is realised that there is at present every likelihood that this cannot ho adhered to in its entirety until, ns has been indicated, further conservation has Iwcn effected or more favourable seasons experienced. (2) It would appear that the do* partment has been over-6ptiraist,ic m regard to the water available lor irr»gallon, and consequently over-sellinjS of water has resulted in bringing in a creator acreage o£ land than cau lie supplied from the available watei sources. Tho commifiee has, owing to water shortage, recommended that one area of (500 acres he reduced to ;iOO acres. This land was served by water at a late date, and is not yet fully developed. If in future tho water supply to tho deleted area can 1) 0 restored; it is recommended that this he done. It is recommended that in the meantime the rates and water allocation shown in tho schedule be adopted'.