DEPARTMENT OF LANDS AND SURVEY RANGITAIKI LAND DRAINAGE REPORT FOR THE YEAR ENDED 31st MARCH, 1945

Appendix to the Journals of the House of Representatives, 1945 Session I, C-11

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1945 NEW ZEALAND

DEPARTMENT OF LANDS AND SURVEY RANGITAIKI LAND DRAINAGE REPORT FOR THE YEAR ENDED 31st MARCH, 1945

Presented to "bo<th Houses of the General Assembly in pursuance• of Section 10 of the Rangitaild Land Drainage Act, 1910 Department of Lands and Survey, Wellington, Ist June, 1945. Sib, — I have the honour to submit herewith the report of the Chief Drainage Engineer on drainage operations on the Rangitaiki Plains for the year ended 31st March, 1945, pursuant to the provisions of the Rangitaiki Land Drainage Act, 1910. I have, &c., R. G. Macmorran, Under-Secretary for Lands. The Hon. the Minister of Lands.

REPORT OF THE CHIEF DRAINAGE ENGINEER Sir, — In accordance with the provisions of the Rangitaiki Land Drainage Act, 1910, I have the honour to submit a report on the work carried out during the year ended 31st March, 1945. The outstanding feature of the year has been the resolute effort of the settlers in the district to repair the ravages of the floods of February and March, 1944. Pastures destroyed by the floods have been re-established, and dairy herds have returned to farms from which all stock had to be removed. The butter manufactured at the Edgecumbe Dairy Factory, which is supplied by the farms of the district, was 4,482 tons and 4,711 tons for the years ending 31st March, 1944 and 1945, respectively. _ The peak output for this factory is over 5,000 tons per annum, and taking into consideration the destruction and disorganization on the farms caused by the floods, the production figures for these two seasons are remarkable. Though no serious flooding occurred during the 1944-45 fiscal year, conditions were not favourable for high production. Some minor flooding occurred in July, 1944, and in 1945. An exceptional rainfall of 7-32 in. in; twenty-four hours ending at 9 a.m. on the 6th March, 1945, did not cause serious flooding, though the drains were overtaxed. The total rainfall for 1944-45 was 44-46 in., which is below the average of 50-31 in. over a period of twenty-seven years. The wettest month was March, 1945, with a fall of 8-93 in., and the driest month February, when the rainfall was 1-28 in. Rain fell on eighty-seven days, There is a considerable area of peat and marsh soil with intersecant ridges of silt, or sand, generally formed by overflow along the banks of old watercourses. Many of these old watercourses have been and are still covered by peat, and as the peat subsides as the result of drainage the firm ridges appear, the contour of the land alters, and the drainage conditions change. To assist in determining the amount of subsidence to be expected in future and give an indication of the final contour of the country when subsidence ceases, a topographical and soil survey of the district has been commenced, and will proceed as fast as possible. Preliminary surveys of an area of 20 square miles have been made, involving 8,345 chains of levels, 2,830 chains of traverse, and 173 boreholes varying: in depth from 6 ft, to 24 ft, For several years small land-drainage pumping plants have been operated by individual fanners or groups of farmers for, the better drainage of low-lying areas. With persistent subsidence of the land, the area requiring mechanical drainage is increasing, and this will necessitate greater pumping capacity and higher suction lifts. Adjustments will have to be made to existing pumping plants, and if duplication and conflict is to be avoided, pumping schemes must be designed to conform to an overall plan. With the information obtained by the survey now being carried out, this will be "possible in future. To cope with emergency repairs of flood damage, two additional drag-line, excavators, released from defence work, arrived at Rangitaiki late in March, 1944, and four drag-line excavators have been employed on maintenance and repair work in the district throughout the year under review. Practically all construction equipment of this type now Zealand is well worn by years of forced wartime construction that did not allow time for regular overhaul, and the machines have now reached a stage where work is frequently interrupted by breakdowns, and delay is caused by difficulty in replacing worn-out parts. It will be apparent, however, from the details given below that the four machines have accomplished a very considerable amount of flood-damage repair and drain-maintenance work. No. 17 Monighan Drag-line Excavator has been employed removing silt from the Awaiti Stream and reconstructing the right stop-bank with the spoil. Prior to Ist April, 1944, the plant had completed a reach of 100 chains downstream from the junction of the Omeheu Canal with the Awaiti Stream. During the following year the plant worked

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downstream to the junction of the Awaiti Stream and Tarawera River, and continued down the Tarawera River, reconstructing the! stop-bank to the Tauranga-Whakatane Highway Bridge. For future operations the machine has. to travel to the Rangitaiki River. For part of the route it must return along the Awaiti Stream. For this reason, work on the stream was carried out in two stages. Working downstream, the heavy growth of willows was removed and the bases of the stop-bank built, to be raised as the plant returned upstream. The quantity of silt removed from the channels and built into the stop-banks during the year was 54,281 cubic yards. No. 30 Bay City Excavator, Model 20.—Between the 3rd April and 9th May this machine repaired breaches in the right stop-bank of the Waioho Canal, and replaced the material washed from the roadway on the right bank of the canal into the roadside drain. It then, deepened Fortune's Drain, and was laid up for overhaul at the Thornton Depot between 29th May and 15th October. After repairing a flood-gate and stop-bank on the Omeheu Canal and enlarging the, lower 20 chains of Walker's Drain, the machine was, on the 13th November, moved by tractor to Te T'eko to remove the spoil-bank on the Edgecumbe Catchwater Drain for a distance of 32 chains. During December and January this plant was employed repairing the right stop-bank on the Rangitaiki River for a distance of 30 chains south of the railway, removing silt from the White Pine Drain and Orini Stream, and from the 12th February it has replaced a broken-down machine cleaning the Tarawera Western Drain. The total quantity of earth handled by the machine on the various jobs during the year was 28,401 cubic yards. No. 32 Rustom, Bucyrus Excavator, Model 10. —For the first seven months of the year this machine was employed entirely on flood-damage repairs, including restoration of partially destroyed stop-banks on the Rangitaiki River between Thornton and Edgecumbe, similar work on the Whakatane River below the outlet of the Te Rahu Canal, and on the Tarawera River near the mouth of the Waikimiki Stream. In some cases, earth for filling gaps in the stop-bank was loaded into motor-trucks by the excavator. Six thousand six hundred cubic yards of earth, scoured by flood-water from railway and road embankments and the drain banks, were removed from Reid's Central Drain for a distance of 113 chains. In October and part of November the spoil-bank on the western side of the Te Rahu Canal was formed into a medium flood-level stop-bank for a distance of 29 chains down-stream from the Whakatane-Rotorua Highway. This necessitated the removal of a number of large pine-trees growing on the canal bank. After forming a service road from the Manawahe Road into a new quarry, the machine was transported by road to Otakire, where it cleaned the Tarawera Western Drain for a distance of '190 chains before the end of January, when a complete breakdown necessitated the removal of the plant for overhaul at the Thornton Workshops. The output for ten working months was 24,686 cubic yards. No. 33 Ruston Bucyrus Excavator, Model 17.—This machine arrived at Thornton on the 21st March, and after repairs commenced work on the Te Rahu Canal on the 11th April, 1944. Work has been interrupted by floods in the canal and difficulties caused by the soft nature of the banks on which the machine must move, and the plant was idle for three months undergoing workshop overhaul. It has reconditioned the Te Rahu Canal for a distance of 134 chains up-stream from the Whakatane-Rotorua Highway, raising the right stop-bank where required with silt taken from the canal. The quantity of silt removed was 43,519 cubic yards. The total output for the four excavators was 150,887 cubic yards. The principal works carried out by manual labour were cleaning 116 miles of drains, excavating 1,624 cubic yards to widen and deepen 110 chains of drain, bank-protection work on the Rangitaiki River, cutting willows on the banks between Thornton and Edgecumbe, bank-protection work on the Tarawera River, reconstruction of two flood-gates damaged by floods, placing 2-ft.-diameter pipe culverts at each power pole on the Edgecumbe Railway Road Drain, and controlling noxious weeds on river-bank and drain reserves. Two three-roomed cottages were erected at Thornton for married workmen. A tractor was employed for several months removing willows and trees from the banks and waterways of rivers, canals, and drains, and 65 chains of drain was cleaned by weedcutting launch. The workshop at Thornton was enlarged and the machinery adapted for operation by electric motor in place of internal-combustion engine, and an electrical welding plant was installed. All plant repairs have been carried out at the Thornton Depot, and this has greatly reduced time losses for the earth-moving plant. Expenditure and Rates Expenditure on maintenance for the year amounted to £14,845. Rates struck: Special, £10,592; general, £6,072. Rates collected, including arrears: Special, £11,065; general, £6,600. Native. Rating The total Native rates paid, including arrears, during the year under review was £1,594. Native rates levied for the year 1944-45 amounted to £1,781. I have, &c., R. L. Innis, Chief Drainage Engineer. The Under-Secretary for Lands, Wellington. STATEMENT OF ACCOUNTS A statement of accounts is published in parliamentary paper 8.-l [Pt. IV],

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