D.—la.

Assuming the water taken out of the river at the Kawhatau and carried to the Makohine —the distance is about nine and a half miles by the probable conduit-route —the total fall obtainable is just over 300 ft. Water can be taken at about the river-level by a suitable weir, or at levels of say 50 ft., 100 ft., or 150 ft. above the ordinary low-water level by dams. The dams could be used to store some days' supply, or merely to store the overnight low-water flow, and use the height to give extra head. This is probably the best alternative, as giving the greatest amount of power. The tunnel would be on a grade of about 6 ft. per mile to a point as near the power-station as possible, then in tunnel on a steeper grade, lined with armoured concrete as required, and the last length would be of steel pipes. For the low-water flow of 1,500 cubic feet per second, various schemes can be formulated. Some in the table below. The energy is supposed to be distributed to the districts around the power-station south to Palmerston North, and north to say Wanganui.

Kawhatau to Makohine Flat.

The above table outlines what results might be got from the river, and the cost. One great trouble with a large scheme like this would be the intermittent use of a large portion of the power. In a large power-installation in Berlin, up to a certain period of its history, the largest amount of power actually taken at one time was 60,000 kilowatts out of a possible output of 84,000 kilowatts. Business, if offering, could of course be undertaken beyond the actual capacity of the plant to such an extent that the probable maximum power likely to be used would not exceed the capacity of the plant. This difficulty will apply to all schemes, except, perhaps, some specially favourable ones supplying special industries. The lake above a dam would act as a settling-reservoir for a long time, depending on the activity of denudation in the river-basin. After a time this reservoir would fill up, and the passage of shingle over the dam would tend to wear it. Then the question would arise as to cost of repairs to dam, as against dredging the shingle over to prevent excessive cutting. This would mean an increase of cost of working, but by how much could only be determined by actual experience for each river. Silt-laden water would in time have an effect on tunnel-lining. This would begin to be felt after a time in the case of a scheme taking water at ordinary level, but with a high dam it would not arise till after a considerable period. Ultimately it would have to be met by tunnel-repairs, dredging of deposits above the dam, or otherwise, as might seem best. The construction of works of the magnitude above outlined for the utilisation of the Rangitikei is evidently for the distant future. In a district without mineral resources, and without present manufacturing industries, there appears to be no prospect whatever of finding uses for the large amount of energy obtainable from this river, though if the energy could be utilised, any of the schemes would be a success. If a smaller scheme were required for the Rangitikei, the proper course is to utilise the river further up the valley and transmit energy from a greater distance. No very definite information is available for the Rangitikei above the Hautapu junction, but no doubt many schemes are possible on the Rangitikei and on the Moawhanga, and probably they would be less costly per horse-power for the hydraulic part of the schemes than those I have outlined, but the cost for transmission-lines would be relatively greater. Manawatu River, Etc. The Manawatu Gorge has attracted some attention as a possible power-scheme location. The fall in the river is not great enough in the four miles of gorge to justify any attempt being made to construct a power-station here, and the several roads, the railway, the bridges, also the flat agricultural land above the gorge do not allow of any attempts at damming. Schemes to supply local industries of the future could possibly be got in the Oroua and Pohangina. These would be located near the mountains, and be of no great size. The rivers rising from the east slopes of the Ruahine Range would probably yield some schemes also in their upper reaches. No information is available about any of them. The head-waters of the Tukituki and Waipawa might furnish some small schemes, also those of the Ngaruroro should give some schemes if sufficient|fall is obtainable in reasonable distances. The Mohaka is a stream that might also yield some power.

10

Power, b.h.p. Cost. Bevenue. <To dam (24 hours) iO ft. dam — 24 hours ... 12 hours ... .00 ft. dam— 24 hours ... 12 hours ... .50 ft. dam— 24 hours ... 12 hours ... 30,000 £ 1,060,000 & 216,000 36,800 73,600 1,230,000 2,030,000 265,000 265,000 43,600 87,200 1,440,000 2,450,000 314,000 314,000 50,500 101,000 1,770,000 2,800,000 363,000 363,000