Fiordland National Park Visitor...

Fiordland National Park Visitor Centre to Control Gates Walk

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34 Walking

2 Te Anau

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3.5 km one-way | 50 minutes one-way

Both Lakes Te Anau and Manapouri are the catchments for the Manapouri Power Scheme, the largest hydroelectric power station in the country. The lakes feed the turbines discharging into Doubtful Sound, from the power station near Lake Manapouri’s West Arm. The Control Gates regulate the flow between the two lakes and ensure that lake levels are managed in accordance with limits based on natural fluctuations. This pleasant lakeside walk passes the Bird Sanctuary.

Access

Fiordland National Park Visitor Centre is on the corner of SH 94 and Lakefront Drive in Te Anau. The start of the track follows the lake south and is signposted from the lake side of the centre.

Track

The track is even and metalled for the entire length. It takes in views of the Jackson Peaks and the Kepler Mountains then briefly enters a tea-tree grove before the Te Anau Wildlife Centre (see Fiordland National Park Visitor Centre to Te Anau Wildlife Centre).

The track then enters a short boardwalk section, passing near the site of Richard Henry’s Hut. To the north, the promontory on which Te Anau township nestles is the foreground to the snow capped peaks and the Earl Mountains in the far distance.

The track continues to follow the shore, arriving at the formidable concrete structures of the Control Gates, which manage the outflow of Lake Te Anau into the Waiau River and Lake Manapouri.

Fauna

Richard Henry was an early resident of Te Anau, who developed a fondness for the local birds and fauna. His passion led to an appointment as the first caretaker of Resolution Island, at the mouth of Dusky Sound.

Feature

Manapouri Power Scheme

New Zealand’s First Conservation Battle

It’s been a hard walk, so I decide to take a swim in Lake Manapouri. Tired trampers legs find bliss in the cool waters of Shallow Bay, aching feet soothed by the fine golden sand. The clag of several days walking washes off and I’m immediately rejuvenated. The sandflies hurry along the dressing process but are not so voracious to stop a lingering look at the view.

I’m not the only one to be enamoured by the sympathetic composition of beach, forest, lake and mountain. The 1960 New Zealand Year Book called Lake Manapouri “the most beautiful of the southern lakes.” Renowned Fiordland aficionado, nature lover and anthropologist James Herries Beattie described his experiences here. “Not only the islands exude loveliness, for it is all around us in the elegance of the whole design, in the symmetry of outline and in that harmony produced by conformity of each to their whole. There is not a discordant note in all this wonderful representation of Nature.” The lake’s original name was ‘Roto-ua’ meaning ‘rainy lake’ then ‘Moturau’ meaning ‘many islands’. Manapouri means ‘lake of sorrowing heart’.

From Shallow Bay I can see three of Lake Manapouri’s 33 islands - Rona Island, Holmwood Island and Pomona Island. Most are unmodified by introduced browsers and harbour complex understoreys, resplendent with orchids. Glimpses of the sinuous coastline spy other perfect beaches, towered over by sombre green rainforest and tussock tops. In the North, South and West Arms, snow lies year round on some peaks, which rise like sentinels and give the lake a fiordesque feel. With her larger sibling, Lake Te Anau, these two jewels exude power and tranquillity. They are inspiration for artists, photographers and casual tourists, who all leave indelibly impressed.

Approaching Manapouri’s West Arm, this stronghold of the Natural world conceals an unlikely human imprint. There, nearly 200 metres underground is a bloody great power station, spawning triffid-like pylons and sprouting a 10 km long tunnel to Deep Cove in Doubtful Sound. This is New Zealand’s single largest hydro-electric facility and was nearly responsible for drowning the abundant loveliness around. Were it not for the efforts of an impassioned core of conservationists, the lakeshores would be a mess.

Post War New Zealand was on the up. Massive investment poured into infrastructural development as the wee global backwater tried to shake its reliance on agrarian economies. Roads, dams, housing, manufacturing industry all developed virtually unchecked. Then in 1960 John Salmon published Heritage Destroyed, a stark appraisal of the gung-ho attitude to the bulldozer. The New Zealand preservation Society formed in Christchurch and The Royal Forest and Bird Protection Society initiated rumblings about the proposals for Lake Manapouri.

As early as 1904, P.S. Hay of the Public Works Department noted the hydroelectric potential of Lakes Manapouri and Te Anau. It’s obvious. The catchments cover 4,500 square kilometres, including some of the wettest mountain ranges on Earth. Furthermore, the 200 metre elevation is only 10 km as the falcon flies from sea level at Deep Cove. That is hydro-electric potential.

In 1930 the American Cyanamid Company of New York were commissioned to write a report on the possibilities. They set out a list of facts and costs without appraisal, but presented no barriers to the possibility. Other groups makes murmurings, then in 1952 Ministry of Works got serious. They engaged the Southland Progress League to bounce ideas off, promoting the grand scheme as an attractor for international investment. In 1956 Consolidated Zinc Proprietary Ltd approached the New Zealand Government with the idea of an aluminium smelter. The world’s largest deposit of bauxite, the ore from which aluminium is eventually derived, had just been unearthed in northern Queensland. But to manufacture the finished metal needed electricity - and lots of it.

One tonne of aluminium requires 15,000kwh of electricity – average domestic consumption over two years. The modified bauxite (alumina) is put in pot lines and heated to 1150 degrees Celsius, where an anodised plate attracts the positively charged aluminium. The pot lines require a steady reliable supply. The plant was expected to eventually produce over 200,000 tonnes of aluminium a year, requiring around 500MW of power.

The Labour Government moved quickly and covertly to set up the paperwork, handing Manapouri-Te Anau water rights to Consolidated Zinc in 1960 - on a silver platter. ‘Go ahead, do what you want and raise Manapouri by 25 metres to create a single storage lake’, was the essence of the agreement. Although with no legislative basis, the Manapouri-Te Anau Development Act was swiftly passed and to hell with breaching the 1952 National Parks Act. The succeeding National government bowed to the corporate whinging a decided to take on the cost of the power station itself, selling excess power to the national grid. They also upped their estimate of the station’s potential from 400 MW to 700 MW. The Waiau would no longer flow in such majestic proportions.

By 1963 Bechtel Pacific Corporation won the design and supervision contract with the Utah Construction and Mining Company undertaking the main contracts for the tailrace tunnel and Wilmot Pass Road. The diameter of the tailrace tunnel was critical, as tunnelling through the granite was costly. In fact ludicrously expensive. It was much easier and cheaper to just raise the lake level, provide a greater head of water and construct a smaller (and cheaper) tunnel. The engineers did their sums and voila. Lake Manapouri was to be raised by 8.4 metres.

Work commenced on the construction of the power station. The scheme planned to divert water from the Waiau River through an underground powerhouse at West Arm and a 10 km long tunnel discharging into Deep Cove in Doubtful Sound. Remoteness, difficult access, torrential rain, extreme temperatures, snow, and sandflies posed a unique set of problems and unsurprisingly many stories unfurled from the 5-year project. This was construction on the scale of a James Bond movie. It took 1,800 workers eight years to build.

The tailrace tunnel was undoubtedly the main construction hurdle. At 10km long, 9.1 metre diameter, with a modified horseshoe section, it was reinforced with rockbolts and wire mesh then lined with concrete. 782,904 m³ of rock removed, 210,906 m³ of concrete lining nearly 600 men working for five years. Prime Minister Holyoake fired the first shot in February 1964. A railway system was set up to remove the spoil, drawn by electric locomotives and dumped at Deep Cove to form a spillway embankment. A 45-ton jumbo, or drilling rig inside the tunnel was mounted on rails and supported 18 high speed drills driven by compressed air. These pierced the holes later filled with explosives. Muckers cleared the debris and moved forward with the blast face on a mobile switchyard. Work was dark, cool and wet, with 5,000 gallons of water per minute being pumped. A 15 inch thick concrete lining reduced friction to ease the flow of water. Concrete was stored in silos at Deep Cove then fed on a conveyor into the tunnel. A full set of workshops, powerhouse and air pumping station were set up at Deep Cove.

The 21.6 km Wilmot Pass Road is the arterial link between the two centres. Work started from both ends and excavated nearly 1 million cubic yards of material to traverse the 671 metre Wilmot Pass. It cost $80 per metre. The day both sides met, contractors put on a ‘Road Shout’ with 480 cans of beer and 12 bottles of whisky going down the hatches. The rest of the day was a holiday.

George Howard worked on the construction project and gives a human face to conditions in his book The Heart of Fiordland. He recounts how when the West Arm accommodation buildings were barged over from Manapouri it took nine hours. The prefabricated buildings were laid out like a Roman army camp. Overseas men found the incessant pestering of sandflies too much and some left.

At Manapouri, a Hydro Village sprang up about 4 km from the township. It’s 800 residents included 367 kids. Services were later added including a service station, coffee bar, barbers, hall, library and cinema. The supermarket was a real coup as this ‘avoided the long drive to Te Anau.’ The local rag Manapouri Messenger gave commentary on the village life and project workings. One advertisement read: ‘Don’t fault your wife’s cooking! Enjoy and evening at the Manapouri Licensed Restaurant, where you can both find fault together.’

Men worked round the clock in three eight hour shifts. It was a mans world. After work, they would hang up wet clothes in the drying room, wash and sit down to a hot meal. Darts, reading and a couple of beers were the evening’s entertainment. It was a right cosmopolitan bunch, men hailing from Scotland, Germany, Denmark, Yugoslavia and America. No day passed without a bit of harmless nationalistic heckling.

The Wanganella floated into Deep Cove on 29th August 1963. One mystery aboard that was never solved involved missing underwear. As all men used the same drying room and wore similar clothes, sometimes mix ups occurred and the wrong underwear was attired. Advice to new arrivals was: ‘Leave your valuables around, they’ll be safe. But watch your underwear.’ The bar was the obvious focal point and lads such as bulldozer driver, 5-foot tall, 20 stone Johnny Martin could down a dozen jugs for breakfast.

In all, around 3,300 tonnes of explosives were used in the entire construction project. After blasting, electric fans would suck out the fumes. Occasionally drillers would meet underground springs so pump a loose slurry of cement and water to grout the hole.

The figures for overall construction cost read the accounts of a small African Republic. $41m for the tailrace tunnel, $47m for the powerhouse and access tunnel, $135m in total. 437,300,000 gallons of water were pumped from the tunnel.

No amount of fudging could hide the fact any raise would be disastrous for the lake. All the evidence was still hauntingly present at Lake Monowai, where a 2 metre raise in 1926 had drowned the lakeshore communities, now scarred with ghostly stumps. Clearing vegetation around Lake Manapouri to mitigate the effects was an impractical and preposterous idea. Then in the summer of 1969-70 Associate professor of Botany at University of Otago, Alan Mark and a sprightly honours student Peter Johnson made a lakeshore vegetation survey of the lakes. Their studies unequivocally showed a response of vegetation patterns to changing lake levels, based on the system of zonation.

Of the seven zones, aquatic plants stretched to below 6m below the mean water level, then an inter-tidal zone of turf communities. Over 45 species were discovered in this schizophrenic zone, sometimes wet, sometimes dry. The sedge zone (Carex gaudichaudiania) then runs into a jointed rush Leptocarpus similis and a shrubland belt of manuka, buffering the beech forest behind. Five nationally endangered species occupy the area including Iti lacustris (now named Cardamine ), found few other places on Earth. The point of this research spelled out clearly this was an ecosystem to preserve, not drown. A highly adapted set of species had evolved to tolerate submergence, exposure and wave action.

Evidence of the likely repercussions from higher lake levels mounted. Further to the 105 km of coastline which would be damaged, 17 of Manapouri’s 33 islands would be flooded, many free from the ravages of deer and possums. Official figures for the proposed flooded area were found to be gross underestimates. Higher levels would increase the likelihood of slips and this discharge into the lake would affect water quality and aquatic life. Drowning of the manuka buffer would weaken the forest edge trees. Surrounding bogs would endure changing drainage regimes, birdlife would suffer from marked habitat changes. In short, the proposals amounted to ecological catastrophe. It was time to Save Manapouri.

In his book Manapouri Saved, noted southern New Zealand writer Neville Peat provides a detailed account of the bureaucratic trail that ensued. In 1969 the Southland Save Manapouri Committee formed (later undergoing various name changes to Save Manapouri Committee), the hub for a national network of pressure groups. Tourist business owner Les Hutchins voiced opinions from his sector. Royal Forest and Bird Protection Society organised petitions calling for greater transparency. To most it seemed the government were selling out to foreign interests for short-term profit. Comalco, the aluminium company, were to pay too little for their power.

Ron McLean, chair of the Save Manapouri Committee spoke lucidly on TV programmes, to newspapers and at public meetings at Invercargill’s Wool Exchange in 1969 and 1970. His infectious enthusiasm rallied nationwide support and thrust the campaign into the political arena as election time approached. 20 Save Manapouri branches materialised nationwide. 800 attended the inaugural meeting of the Wellington committee. This was too close to home for the politicians and the National Government decided to form a Cabinet Committee to study and report on the proposals.

Branch members scurried about organising meetings, lobbying and writing letters. Efforts were brought together with a national conference in Wellington and formation of a national committee, including Dr John Salmon and Dr Charles Fleming. The Cabinet report touched on campaigners initial misgivings. The area for vegetation clearance would be larger than initial estimates, as were costs for the Mararoa Dam. Most of all however the report stated that the 500MW power requirement could be met 97% of the time with the existing lake level. Progress was being made.

A Commission of Enquiry now needed convincing, which called for big bucks. 30,000 Save Manapouri Campaign share certificates were sold at 50 cents each. The dividend? ‘Retention of Lake Manapouri in its natural state’. On May 26th 1970 Forest and Bird officers presented a petition to Parliament. It required a trolley to convey the 264, 907 signatures, the largest petition ever mounted in New Zealand.

The commission sat for 38 days, received 2000 pages of evidence and maps, diagrams, photographs, plans and press clippings. Nearly all, except Comalco, were in favour of retaining existing lake levels. In submitting its report the commission chose to err on the side of legal safeplay, recommending to Government they were contractually bound to allow Comalco to raise Manapouri to 186 metres. Ron McLean responded by saying, “We have not yet begun to fight.”

Te Anau also started to worry. A maximum operating level of 204 metres was proposed, 2 metres above the highest level recorded in 30 years. No worries said the authorities, we can build dykes and use pumps if it does flood. These Trumpton measures were obviously farcical.

After a public meeting in Wellington, the Dominion rallied to the call, naming Ron McLean ‘Man of the Year’ and the campaign ‘a phenomenon of public affairs in New Zealand, in a year in which conservation became world-wide fashion.’ In June 1971 the government budged a little by recommending the Mararoa Dam be constructed according to existing level, but be wide enough to deal with expected higher levels in the future.

Pomp and ceremony accompanied Prime Minister Holyoake to the opening of the Tiwai Point smelter in November 1971. So did demonstrations. “Who Owns this Country – the New Zealand people or Comalco?” read one placard. Holyoake played to the crowd with the sort of honesty politicians are acclaimed. Manapouri was blatantly an election issue and Labour were quick to promise maintaining lakes at their natural levels. Shortly after the results of the November 25th election were announced, new Labour Minister of Electricity, Tom McGuigan announced: “Lakes Manapouri and Te Anau must be held at their natural levels.”

Norman Kirk’s new government dealt with the Manapouri issue swiftly and decisively. They appointed a group, the guardians of Lakes Manapouri and Te Anau, to recommend guidelines for the lakes’ management. Alan Mark chaired the group, with Ron McLean, Les Hutchins, Wilson Campbell, Jim McFarlane and John Moore as representatives. Their brief was simple. “Report and make recommendations to the Government through the Minister for the Environment on any matters arising from the environmental, ecological and social effects of the construction and operation of the Manapouri-Te Anau hydro-electric power scheme on the townships of Manapouri and Te Anau, the lakes and shorelines of Te Anau and Manapouri, and the rivers flowing in and out of these lakes with particular reference to the effects of lake levels on scenic values, conservation, recreation, tourism and other related activities and amenities.” This was apparently a global precedent – environmental campaigners turned political advisers. Democracy at its best.

The Guardians set to work devising a set of guidelines. Not only were lakes to remain at natural levels, but any fluctuations also had to be within pre-recorded limits. Any venture to extremes could not be repeated until a time had elapsed relating to pre-existing data. Rates of change also had to mimic existing hydrological regimes. The Guardians and their guidelines survived droughts, floods, a change in Government and renegotiation of Comalco’s contract. But one final hurdle remained.

Without a legislative basis, there were no guarantees the battles would not be fought again. In December 1981 the legal process finally solidified, with all political parties and public groups unanimous.

In 1994 Electricity Corporation of New Zealand (ECNZ) put forward an idea. Head loss from retaining existing lake levels and greater than anticipated friction in the tailrace tunnel meant the 700MW capacity installed was underutilised. Current maximum output was 585MW, which could be increased to 800MW with the installation of a second 9 metre diameter tailrace tunnel. The Guardians agreed and work commenced.

This was engineering on a grand scale. Whereas the first tunnel was constructed using drill and blast methods, for the second tunnel a 25-metre long tunnel boring machine was imported. Manufactured by Atlas Copco-Robbins this leviathan of a machine weighed 950 tonnes and with trailing gear was nearly half a kilometre long. Leaps in technology meant the tunnel was mostly unlined. Over 1.5 million man hours went into the project which cost around $200 million. The machine averaged 10 metres advance per day and had 4,084 cutters replaced.

For over 50,00 visitors per year a trip to the power station is as much a part of the day as a bus ride over Wilmot Pass and a cruise on Doubtful Sound. Although the impressive engineering feat leaves a mark on the visitors, it the daunting scale of the scenery which leaves them breathless. Despite the scars to the landscape from the power lines and intakes, it is still the scenic grandeur which is the over-riding impression.

Few are fully aware of how important the work of conservations was or how close Lake Manapouri’s beauty was to complete obliteration. As Neville Peat says, “Manapouri marked the dawning of a green consciousness in New Zealand….Save Manapouri is a cry deeply embedded in the consciousness of New Zealanders.”

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South IslandFiordlandTe Anau

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Reviews

Magdalene Zech's avatar

Magdalene Zech

Germany

Ranking: 10/10

They gave us important weather forecast for the multi day trek we wanted to make. There was a storm forecast so they recommended not to go.

Reviewed almost 6 years ago and experienced in January 2014

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Ann Riley's avatar

Ann Riley

England

Ranking: 9/10

Included visit to Te Anua wildlife centre. Flat, easy walking - birds to see if interested.

Reviewed almost 10 years ago and experienced in November 2009

DOC Managed

Thanks to all the good people working for the NZ Department of Conservation - for all your hard work - making NZ more beautiful, accessable and healthy! Cheers 😍

Nick Morrison's avatar

Nick Morrison

Rankers owner