THE KARAPIRO LAKE

Waikato Independent, Volume XLIII, Issue 4044, 22 September 1944, Page 5

THE KARAPIRO LAKE

ALTERATIONS TO ROADS / BIG BRIDGE FOR MAUNGATAUTARI OUTLET EXTENT OF WORKS SURPRISING The majority of the people of the country are well aware of the construction of the Karapiro Hydro Works and of the magnitude,of the Works proper, but they, and even many of the people of district, can have little idea of the actual effect of the harnessing of the waters of the Waikato River at Karapiro. They do know that when completed the big dam, now well under way in its course of construction, will create an ex- • tensive lake, but few members of the general public can be expected to visualise the preparations necessary to cope with the backed up waters and of the actual effect upon the roads and bridges in the vicinity. With this thought in mind an “Independent” representative, accompanied by an interested friend, set out this week to discover the extent of the alterations to roads, the provision of bridges and culverts, the amount of road deviation ' necessary and the progress already made in this direction. To say the least this portion of the work as- ‘ sociated with the Karapiro Hydro development scheme, is extensive, and one can readily' appreciate that here, alone, will be spent many thousands of pounds, before the switches can be pressed and the turbines 4 at Karapiro set in motion. Extent of the Lake. The extfent of the- new lake to be formed is approximately 17 miles in length and about half a mile at its widest point. It is possible there may be one or two' slightly wider parts where the backed up waters, rising to the higher level, will find bays and inlets at the mouths of tributaries to the Waikato River. It is estimated that the southern end of the lake will be about where the waters join the tail race of Arapuni. It is the general impression that the backing-up of the waters will involve large areas of private farmlands, but this is not the case. It is true that some farmlands will be flooded, or “drowned out” as the engineers term it, but by no means to the extent anticipated by some Npeople. The areas chiefly effected will be several low-lying flats on the Maungatautari side of the river, including portion of Mr J. C. Wallace’s and adjoining farms. The valley approaching and including the site of Mr Shelton’s petrol station, will be covered, while portions of the Horahora-Arapuni Road may be covered. Every precaution | has, of course, to be taken to provide for flood conditions and it is in this connection that much explorative work and consideration of book records of the river, have had to be tifken into consideration. • The writer now proposes to try and take his readers on the tour of inspection as actually made this week. We would ask our readers | to visualise that they are returning from Arapuni along the Horahora Road, and by the way, it is still nearly as badly corrugated and bumpy as ever. At a point about three miles below Arapuni a new road commences. It takes a slight incline to the east and the line of the new road crosses the Little Waipa about six chains further to the east than the present small bridge over this stream. At the point where the new road line crosses the stream an extensive culvert will be provided and the cutting and excavation work for this is under way. As one proceeds along the existing road towards the Horastation it is observed that the of the new road takes in the higher portions of the existing road down to about three-quarters of a mile from the station. Here the new line straightens the road considerably. A steep dip has been Tilled in* and bulldozers were at work on this portion. The Pokai stream is crossed further to the east and here provision is being made for a culvert. After passing the Horahora Station, tlft> power section of which will be drowned out, the new road will follow a line

to the east, but with a gradual incline. This travels along a higher level and cuts out the steep hill where the existing road runs along side the river before one approaches Maungatautari turn-off. At a points somewhere about half a mile on the Arapuni side of the turn-off the new road will turn to east and will come out and with the Rotorua main Wat kin’s. A Eiir Steel Bridge. pj At the Maungatautari-Horahora turn-off a new cutting is • being > ; excavated. The river will still be ; crossed to Maungatautari at the same point, but a new steel span "bridge will take the place of the existing bridge. It has been stated Hhat this bridge will have the longest steel girder span in New Zeaand. * Its two points on opposite sides of the river are two bluffs

and the new bridge will be almost directly over the old bridge, but will be about 50 feet greater in height. When the lake is formed the bridge will still be about 20 feet above the level of the waters.

Proceeding , ont towards Cambridge along the main Rotorua highway one now enters the valley where the petrol station is situated. Mr Shelton’s station will be placed on higher ground somewhere near the Horahora turn-off. It is easy to pick up the new road line coming towards Cambridge, because of the clearing and burning of undergrowth. One would estimate that in this valley the new road will traverse a parallel line about 50 feet above the existing highway. The distance of the old road in the valley that will be “drowned out” is aproximately one and a-third miles. Along this stretch of practically cliff face there is a lot. of work for the bulldozers. At the end of the stretch last mentioned the new road will join up with the existing highway. This is the „extent of the alterations and deviations, etc., on this side of the river. On the Western Side.

With the banks of the Waikato River much more precipitous on the western side of the river there will be little change, apart from the flooding of farm-lands, until the low-lying portion of the Maungatautari road is reached. Here there is a .deviation to the west. The new road, already formed, passes through private property and links up again with the existing road about 100 yards on the Cambridge side of Mr Suckling’s homestead. As previousy reported Mr Suckling will have, eventually, what will be known as one of the really original lake-side sites. Progress At the Dam Proper.

. Progress at the dam proper, appears to be satisfactory, though it was stated that there was still a shortage of skilled labour. The three penstock tunnels have been set into their concrete beds and here a lot of work has been entailed, apart from the work that has been going on in the siphon and spillway sections. Excavating is still going on in the original bed of the river and a lot of work has been entailed on the western side of the dam. Between the upper coffer dam and the site of the dam proper there has grown a veritable mountain of spoil. This, it is understood, will remain and will now act as a buffer for the surge of waters against the face of the dam. Operation of Karapiro.

Recently it was mentioned in the “Independent” that it was hoped to have the Karapiro Works operating in the winter of 1940 and the writer observes that the Minister of Works, Hon. R. Semple, confirms this in his annual statement issued on Tuesday last. It would be operating with a preliminary output of 90,000 k.w.

MINISTER SUMMARISES PROGRESS:

Mr Semple also mentions that it is over 30 years since the State embarked on its first major electrical supply scheme, and its operations now represent one of the largest commercial undertakings 'in New Zealand.

Summarising progress in wartime, the Minister says that in spite of difficulties generating capacity increased 37 per cent, in the period 1939-44, namely, by 00,000 k.w. in the North Island and 30,000 k.w. in the South Island. It is expected that delivery of the two 21,000 k.w. units for Arapuni will be completed in time to enable them to be used in the financial year 1944-45 and 1945-40 respectively. Plant for Aralpuni.

Work has been started on a third power station at Kaitawa, Lake Waikaremoana, and ym'eparatory work has begun on a project for a station at Maraetai, on the Waikato River. In the South Island the 900 k.w. scheme on the C,obb River is operating. The Highbank undertaking, near Methven, of 25,000 k.w. will be ready in the next month or so, and work has been recommenced on the Lake Tekapo station, of the same capacity. A definite programme of expansion at the rate of 40,000 k.w. a year will be pursued after the war.

Owing to delays in delivery of plant or order for Arapuni it became necessary to send the inspecting electrical engineer overseas to endeavour to expedite matters. The engineer has been directed to make further inquiries into the possibility of obtaining modern steam generating plant of substantial capacity for stand-by purposes. Inquiry is also being made regarding secondhand generating plant to help in overcoming the present power shortage, but so far no feasible proportion has been -received.