The Central North Island contains some of New Zealand’s star attractions, many the result of its explosive geological past. It’s dominated by three heavyweight features: Lake Taupo, the country’s largest; Tongariro National Park, with its trio of volcanoes; and the volcanic field that feeds colourful and fiercely active thermal areas, principally around Rotorua, where boiling mud pools plop next to spouting geysers fuelled by super-heated water, drawn off to fill hot pools around town. Accessible Maori cultural experiences abound here, with highly regarded Arawa carvings and groups who perform traditional dances and haka before a feast of fall-off-the-bone meat and succulent vegetables cooked in a hangi underground steam oven.
The dramatic volcanic scenery of Rotorua is striking for its contrast with the encroaching pines of the Kaingaroa Forest, one of the world’s largest plantation forests, with serried ranks of fast-growing radiata (Monterey) relishing the free-draining pumice soils. In recent years, high international milk-powder prices have fuelled a large-scale conversion to dairying, but silviculture remains the area’s chief earner.
The rest of the region is loosely referred to as the Volcanic Plateau, high country overlaid with a layer of rock and ash expelled two thousand years ago, when a huge volcano blew itself apart, the resultant crater and surrounds filled by expansive Lake Taupo. This serene lake, and the streams and rivers feeding it, have long lured anglers keen to snag brown and rainbow trout, while visitors flock to diverse sights and activities located near the thundering rapids on the Waikato River, which drains the lake. South of Lake Taupo rise three majestic volcanoes in Tongariro National Park, created in 1887 – a winter playground for North Island skiers and a summer destination for trampers drawn by spectacular walking trails.
The altitude of the Volcanic Plateau lends Taupo, the Tongariro National Park and environs a crisp climate, even in high summer. Spring and autumn are tolerably warm and have the added advantage of freedom from the summer hordes, though the freezing winter months from May to October are mainly the preserve of winter-sports enthusiasts. Rotorua is generally balmier but still cool in winter, making the thermal areas steamier and hot baths even more inviting.
Many of the best attractions in the area lie outside the city itself but shuttles and tours mean that just about every combination of sights can be packed into a day, as well as all manner of adventure activities – from rafting to skydiving.
Travellers can quickly dispatch minor sights along the eastern shore of Lake Rotorua, leaving time for the seldom-crowded Hell’s Gate thermal area and the opportunity to watch terrified rafters plunging over Tutea’s Falls. Rewards are more plentiful to the east and south especially around the shattered 5km-long massif of Mount Tarawera. During one cataclysmic night of eruptions in 1886 this chain split in two, destroying the region’s first tourist attraction (the beautiful Pink and White Terraces), entombing the nearest settlement, Te Wairoa, now known as the Buried Village, and creating the Waimangu Volcanic Valley. It now ranks as one of the finest collections of geothermal features in the region alongside kaleidoscopic Wai-O-Tapu, with its daily triggered Lady Knox Geyser, boiling mud, and brilliantly coloured pools. Other magnificent geothermal areas around Rotorua include Kerosene Creek, which has the best free hot pools hereabouts, and Orakei Korako, which offers a peaceful geothermal experience. Meanwhile, the Whirinaki Forest Park presents great hiking and biking opportunities on the road to Lake Waikaremoana.
Volcanic activity provides the main theme for attractions southeast of Rotorua, most having some association with Lake Tarawera and the jagged line of volcanic peaks and craters along the southeastern shore, collectively known as Mount Tarawera, which erupted in 1886.
Prior to that eruption Tarawera was New Zealand’s premier tourist destination, with thousands of visitors every year crossing lakes Tarawera and Rotomahana in whaleboats and waka, frequently guided by the renowned Maori guide Sophia, to the Pink and White Terraces, two separate fans of silica that cascaded down the hillside to the edge of Lake Rotomahana. Boiling cauldrons bubbled at the top of each formation, spilling mineral-rich water down into a series of staggered cup-shaped pools, the outflow of one filling the one below. Most visitors favoured the Pink Terraces, which were prettier and better suited to sitting and soaking. All this came to an abrupt end on the night of June 10, 1886, when the long-dormant Mount Tarawera erupted, creating 22 craters along a 17km rift, and covering over 15,000 square kilometres in mud and scoria. The Pink and White Terraces were shattered by the buckling earth, covered by ash and lava, then submerged deep under the waters of Lake Rotomahana.
The cataclysm had been foreshadowed eleven days earlier, when two separate canoe-loads of Pakeha tourists and their Maori guides saw an ancient waka glide out of the mist, with a dozen warriors paddling furiously, then vanish just as suddenly; the ancient tohunga (priest) Tuhoto Ariki interpreted this as a sign of imminent disaster. The fallout from the eruption buried five villages, including the staging post for the Pink and White Terrace trips, Te Wairoa, where the tohunga, lived. In a classic case of blaming the messenger, the inhabitants refused to rescue the tohunga and it wasn’t until four days later that they allowed a group of Pakeha to dig him out. Miraculously he lived, for a week.
In 2011, scientists discovered that rather than being completely destroyed, parts of the Pink Terraces appear to have survived the 1886 eruption (the White Terraces are thought to have been more likely to have been affected). The gas and hot water vents discovered on the lake floor indicate rare active underwater geothermal systems, which scientists are continuing to research.
Wai-O-Tapu Thermal Wonderland, 10km south of Waimangu, is the area’s most colourful and varied geothermal site. At 10.15am daily, the 10m Lady Knox Geyser is ignominiously induced to perform by a staff member who pours a soapy surfactant into the vent. If you miss the geyser your ticket allows you to come back next morning.
Everyone then drives 1km to the main site where an hour-long walking loop wends its way through a series of small lakes which have taken on the tints of the minerals dissolved in them – yellow from sulphur, purple from manganese, green from arsenic and so on. The gurgling and growling black mud of the Devil’s Ink-Pots and a series of hissing and rumbling craters pale beside the ever-changing rainbow colours of the Artist’s Palette pools and the gorgeous, effervescent Champagne Pool, a circular bottle-green cauldron wreathed in swirling steam and fringed by a burnt-orange shelf. The waters of the Champagne Pool froth over The Terraces, a rippled accretion of lime silicate that glistens in the sunlight.
As you drive back to the main road, follow a short detour to a huge and active boiling mud pool which plops away merrily, forming lovely concentric patterns.
On the town’s outskirts is a concentration of natural wonders, all within a few minutes of one another. Here you’ll find boiling mud, hissing steam harnessed by the Wairakei power station, and the clear-blue Waikato River, which cuts a deep swirling course north over rapids and through deep-sided gorges.
The majority of sights and activities are within 10km of Taupo, flanking the Waikato River as it wends its way north, and are accessible through Taupo’s tour companies. Huka Falls Road loops off SH1 a couple of kilometres north of Taupo and passes the Reids Farm free campsite and Huka Lodge (one of New Zealand’s most exclusive luxury retreats) en route to the first port of call, the magnificent Huka Falls (hukanui, or “great body of spray”). Here the Waikato, one of New Zealand’s most voluminous rivers, funnels into a narrow chasm before plunging over a 9m shelf into a seething maelstrom of eddies and whirlpools; the sheer power of some three hundred tonnes of water per second makes it a far more awesome sight than the short drop would suggest. A footbridge spans the channel, providing a perfect vantage point for watching the occasional mad kayaker making the descent, usually on weekend evenings. The car park is only open until 6pm but you can park outside and walk in at any time.
Travelling beyond the immediate vicinity of Taupo, SH1 hugs the lake as it heads southwest to Turangi, while SH5 veers southeast along the Napier–Taupo Road, a twisting ninety-minute run through some of the North Island’s remotest country. Much of the early part of the journey crosses the Kaingaroa Plains, impoverished land cloaked in pumice and ash from the Taupo volcanic eruption and of little use save for the pine plantations which stretch 100km to the north. The history of this route is traced by the Napier–Taupo Heritage Trail; pick up a free booklet from either town’s i-SITE.
You smell Rotorua long before you see it. Hydrogen sulphide drifting up from natural vents in the region’s thin crust means that a whiff of rotten eggs lingers in the air, but after a few hours you barely notice it. The odour certainly doesn’t stop any one from visiting this small city on the southern shores of Lake Rotorua. Indeed, this is the North Island’s tourist destination par excellence – so much so that locals refer to the place (only half-jokingly) as Roto-Vegas.
A big part of the appeal is that Rotorua is one of the world’s most concentrated and accessible geothermal areas, where 15m geysers spout among kaleidoscopic mineral pools, steam wafts over cauldrons of boiling mud and terraces of encrusted silicates drip like stalactites. Everywhere you look there’s evidence of volcanism: birds on the lakeshore are relieved of the chore of nest-sitting by the warmth of the ground; in churchyards tombs are built topside as digging graves is likely to unearth a hot spring; and hotels are equipped with geothermally fed hot tubs, perfect after a hard day’s sightseeing. Throughout the region, sulphur and heat combine to form barren landscapes where only hardy plants brave the trickling hot streams, sputtering vents and seething fumaroles. There’s no shortage of colour, however, from iridescent mineral deposits lining the pools: bright oranges juxtaposed with emerald greens and rust reds. The underworld looms large in Rotorua’s lexicon: there’s no end of “The Devil’s” this and “Hell’s” that, prompting George Bernard Shaw to quip that the Hell’s Gate thermal area “reminds me too vividly of the fate theologians have promised me”.
But constant hydrothermal activity is only part of the area’s appeal. The naturally hot water lured Maori to settle here, using the hottest pools for cooking and bathing, and building their whare (houses) on warm ground to drive away the winter chill. Despite the inevitably diluting effects of tourism, there’s no better place to get an introduction to Maori values, traditions, dance and song than at a concert and hangi evening.
The lake’s northern and southern boundaries are marked by two ancient villages of the Arawa sub-tribe, Ngati Whakaue: lakeshore Ohinemutu and inland Whakarewarewa. The original Bath House is now part of Rotorua Museum, set in the grounds of the oh-so-English Government Gardens, which successfully and entertainingly puts these early enterprises into context. Half a day is well spent on foot visiting the museum’s fine collection of Maori artefacts and bathhouse relics, and strolling around the lakeshores to Ohinemutu, the city’s original Maori village with its neatly carved church. Afterwards, you can ease your bones with a soak in the hot pools set in a native bird sanctuary by catching a boat out to Mokoia Island.
At the southern end of town, Maori residents still go about their daily lives amid the steam and boiling pools at Whakarewarewa Thermal Village, while the adjacent Te Puia offers the region’s only natural geysers, plopping mud and a nationally renowned Maori carving school.
Where Rotorua’s northwestern suburbs peter out, Mount Ngongotaha rises up, providing the necessary slope for a number of gravity-driven activities at the Skyline Skyrides. In its shadow, Rainbow Springs Kiwi Wildlife Park, provides a window into the life cycle of trout, and an excellent Kiwi Encounter, while the nearby Agrodome fills the prescription for adrenaline junkies.
Some of the region’s finest geothermal areas lie outside the city – For more information, see Around Rotorua.
The Rotorua region is the traditional home of the Arawa people. According to Maori history, one of the first parties to explore the interior was led by the tohunga (priest), Ngatoroirangi, who made it as far as the freezing summit of Mount Tongariro, where he feared he might die from cold. His prayers to the gods of Hawaiki were answered with fire that journeyed underground, surfacing at White Island in the Bay of Plenty, then at several more points in a line between there and the three central North Island volcanoes. Ngatoroirangi was saved, and he and his followers established themselves around Lake Rotoiti (“small lake”) and Lake Rotorua (“second lake”).
Battles and bloodshed
In revenge for an earlier raid, the Northland Ngapuhi chief, Hongi Hika, led a war party here in 1823, complete with muskets traded with Europeans in the Bay of Islands. The Arawa retreated to Mokoia Island, in the middle of Lake Rotorua; undaunted, Hongi Hika and his warriors carried their canoes overland between lakes (the track between Lake Rotoiti and Lake Rotoehu still bears the name Hongi’s Track) and defeated the traditionally armed Arawa. In the New Zealand Wars of the 1860s the Arawa supported the government. In return, colonial troops helped repulse Te Kooti (see box, p.383) and his people a decade later.
The birth of tourism
A few Europeans had already lived for some years in the Maori villages of Ohinemutu and Whakarewarewa, but it wasn’t until Te Kooti had been driven off that Rotorua came into existence. Tourists began to arrive in the district to view the Pink and White Terraces, and the Arawa, who up to this point had been relatively isolated from European influence, quickly grasped the possibilities of tourism, helping make Rotorua what it is today. Set up as a spa town on land leased from the Ngati Whakaue, by 1885 the fledgling city boasted the Government Sanatorium Complex, a spa designed to administer the rigorous treatments deemed beneficial to the “invalids” who came to take the waters.
Rotorua provides more opportunities than anywhere else to sample food steamed to perfection in the Maori earth oven or hangi and watch a Maori concert, typically an hour-long performance of traditional dance, song and chants. The bigger hotels all put on somewhat forced extravaganzas, so go for the “Maori experiences” (daily, by reservation). All have buses picking up at hotels and hostels ready for a start around 6pm, then run for three to four hours. They follow largely the same format, giving instruction on marae customs and protocol followed by a formal welcome, concert and hangi.
Rotorua has a considerable reputation for its nearby whitewater rivers, which you can tackle aboard rafts, kayaks (usually tandems) or, more in-your-face, by “sledging” – floating down rapids clinging to a buoyant plastic sledge (really only for good swimmers). There’s no shortage of operators willing to take you out (usually from September to May); the most popular rivers are listed below. Other options include renting kayaks or undertaking kayaking courses and guided trips on several of the larger lakes in the region, with the emphasis on scenic appreciation, soaking in hot pools and a little fishing.
Kaituna River Much of the hype is reserved for this Grade IV river, or at least the 2km section after it leaves Lake Rotoiti 20km north of Rotorua, which includes the spectacular 7m Tutea’s Falls (sledgers walk around the falls).
Wairoa River If you can get the timing right, this Grade IV+ river, 80km by road from Rotorua, on the outskirts of Tauranga, is the one to go for. It relies on dam-releases for raftable quantities of white water (Dec–March every Sun; Sept–Nov & April–May every second Sun). This is one of the finest short trips available in New Zealand, negotiating a hazardous but immensely satisfying stretch of water.
Rangitaiki River If your tastes lean more towards appreciation of the natural surroundings with a bit of a bumpy ride thrown in, opt for this Grade III river, which also shoots Jeff’s Joy, a Grade IV drop that’s the highlight of the trip.
The Maori love story of Hinemoa and Tutanekai has been told around the shores of Lake Rotorua for centuries. It tells of the illegitimate young chief Tutanekai of Mokoia Island and his high-born paramour, Hinemoa, whose family forbade her from marrying him. To prevent her from meeting him they beached their waka (canoe) but the strains of his lamenting flute wafted across the lake nightly and the smitten Hinemoa resolved to swim to him. One night, buoyed by gourds, she set off towards Mokoia but by the time she got there Tutanekai had retired to his whare (house) to sleep. Hinemoa arrived at the island but without clothes was unable to enter the village, so she immersed herself in a hot pool. Presently Tutanekai’s slave came to collect water and Hinemoa lured him over, smashed his gourd and sent him back to his master. An enraged Tutanekai came to investigate, only to fall into into Hinemoa’s embrace.
The burgeoning resort town of TAUPO, 80km south of Rotorua and slap in the centre of the North Island, is strung around the northern shores of Lake Taupo, the country’s largest lake, which is the size of Singapore. Views stretch 30km southwest towards the three snowcapped volcanoes of the Tongariro National Park, the reflected light from the lake’s glassy surface combining with the 360m altitude to create an almost alpine radiance. Here, the impossibly deep-blue waters of the Waikato River (“flowing water” in Maori) begin their long journey to the Tasman Sea, and both lake and river frontages are lined with parks.
For decades, Kiwi families have been descending en masse for a couple of weeks’ holiday, bathing in the crisp waters of the lake, and lounging around holiday homes that fringe the lakeshore. But there’s no shortage of things to see and do, from the spectacular rapids and geothermal badlands north of town to skydiving – this is New Zealand’s freefall capital – and fishing. The Taupo area is a most fecund trout fishery, extending south to Turangi and along the Tongariro River, with an enviable reputation for the quality of its fish. Year-round, you’ll see boats drifting across the lake with lines trailing and, particularly in the evenings, rivermouths choked with fly-casters in waist-high waders.
Nowhere in Taupo’s compact low-rise core is more than five minutes’ walk from the waters of the Waikato River or Lake Taupo, which jointly hem in three sides. The fourth side rises up through the gentle slopes of Taupo’s suburbs. Most of the commercial activity happens along Tongariro Street and the aptly named Lake Terrace.
Taupo also makes a great base for exploring the surrounding area (see Around Taupo), where highlights include Huka Falls, Aratiatia Rapids, Wairakei Terraces and the Craters of the Moon geothermal area.
The Tuwharetoa people had lived in the area for centuries, but it wasn’t until the New Zealand Wars that Europeans took an interest with the Armed Constabulary trying to track down Te Kooti. They set up camp one night in June 1869 at Opepe, 17km southeast of Taupo (beside what is now SH5), and were ambushed by Te Kooti’s men, who killed nine soldiers. Garrisons were subsequently established at Opepe and Taupo, but only Taupo flourished, enjoying a more strategic situation and being blessed with hot springs for washing and bathing. By 1877, Te Kooti had been contained, but the Armed Constabulary wasn’t disbanded until 1886, after which several soldiers and their families stayed on, forming the nucleus of European settlement.
Taupo didn’t really take off as a domestic resort until the prosperous 1950s, when the North Island’s roads had improved to the point where Kiwi families could easily drive here from Auckland, Wellington or Hawke’s Bay.
Lake Taupo (616 sq km, 185m deep) is itself a geological infant largely created in 186 AD when the Taupo Volcano spewed out 24 cubic kilometres of rock, debris and ash – at least ten times more than was produced by the eruptions of Krakatoa and Mount St Helens combined – and covered much of the North Island in a thick layer of pumice. Ash from the eruption was carried around the world – the Chinese noted a blackening of the sky and Romans recorded that the heavens turned blood-red. As the underground magma chamber emptied, the roof slumped, leaving a huge steep-sided crater, since filled by Lake Taupo. It’s hard to reconcile this placid and beautiful lake with such colossal violence, though the evidence is all around: entire beaches are composed of feather-light pumice which, when caught by the wind, floats off across the lake. Volcanologists continue to study the Taupo Volcano (currently considered dormant) and treat the lake as a kind of giant spirit-level, in which any tilting could indicate a build-up of magma below the surface that might trigger another eruption.
The local Tuwharetoa people ascribe the lake’s formation to their ancestor, Ngatoroirangi, who cast a tree from the summit of Mount Tauhara, on the edge of Taupo, and where it struck the ground water welled up and formed the lake. The lake’s full name is Taupo-Nui-A-Tia, “the great shoulder mat of Tia” or “great sleep of Tia”, which refers to an explorer from the Arawa canoe said to have slept by the lake.
New Zealand’s highly developed network of national parks owes much to Te Heu Heu Tukino IV, the Tuwharetoa chief who, in the Pakeha land-grabbing climate of the late nineteenth century, recognized that the only chance his people had of keeping their sacred lands intact was to donate them to the nation – on condition that they could not be settled or spoiled. His 1887 gift formed the core of the country’s first major public reserve, Tongariro National Park, which became a UNESCO World Heritage Site in 1991 due to its unique landscape and cultural significance (see The Maori mountain legends). In the north a small, outlying section of the park centres on Mount Pihanga and the tiny Lake Rotopounamu, but most visitors head straight for the main body of the park, dominated by the three great volcanoes which rise starkly from the desolate plateau: the broad-shouldered ski mountain, Ruapehu (2797m); its squatter sibling, Tongariro (1968m); and, wedged between them, the conical Ngauruhoe (2287m).
Within the boundaries of the park is some of the North Island’s most striking scenery – a beautiful mixture of semi-arid plains, steaming fumaroles, crystal-clear lakes and streams, virgin rainforest and an abundance of ice and snow. The more forbidding volcanic areas were used as locations for Mordor and Mount Doom in the Lord of the Rings trilogy. All of this forms the backdrop to two supremely rewarding tramps, the one-day Tongariro Alpine Crossing and the three- to four-day Tongariro Northern Circuit, one of New Zealand’s Great Walks. The undulating plateau to the west of the volcanoes is vegetated by bushland and golden tussock, while on the eastern side the rain shadow of the mountains produces the Rangipo Desert. Although this is not a true desert, it is still an impressively bleak and barren landscape, smothered by a thick layer of volcanic ash from the 186 AD Taupo eruption. Mount Ruapehu frequently bursts into life (most recently 1995, 1996 and 2007), occasionally emptying its crater lake down the side of the mountain in muddy deluges known as lahars. In 2011 Mount Ruapehu’s Volcanic Alert Level was elevated to level 1 (signs of volcanic unrest), but at the time of writing it was not affecting visitors. Keep tabs on its status with DOC and the local i-SITE office.
The northern approach to the region is through Turangi, which – though it lacks the mountain feel of the service town of National Park and the alpine Whakapapa Village, 1200m up on the flanks of Ruapehu – makes a good base both for the Tongariro tramps and for rafting and fishing the Tongariro River. The southern gateway is Ohakune, a more aesthetically pleasing place than National Park but distinctly comatose outside the ski season. Heading south, the Army Museum at Waiouru marks the southern limit of the Volcanic Plateau, which tails off into the pastoral lower half of the region set around the agricultural town of Taihape, home to the North Island’s highest bungy jump.
Pretty much everyone comes to the park either to ski or to tramp, staying in one of the small towns dotted around the base of the mountains. Note that this region is over 600m above sea level, so even in the height of summer you’ll need warm clothing.
When Te Heu Heu Tukino donated Tongariro’s central volcanoes to the Crown, he was motivated by a deep spiritual need for their protection. According to Maori, the mountains at the heart of the park have distinct personalities that symbolize the links between the community and its environment. This significance was recognized in 1991 when the park became the first UNESCO World Heritage Site included as a cultural landscape.
Legends tell of a number of smaller mountains clustered around the dominating Ruapehu, Tongariro, Ngauruhoe and Taranaki. Among these was the beautiful Pihanga in the northern section of the park, whose favours were widely sought. Pihanga loved only Tongariro, the victor of numerous battles with her other suitors, including one that had brought him to his knees, striking off the top of his head, giving him his present shape. Taranaki, meantime, defeated Ngauruhoe, but when he came to face Ruapehu, he was exhausted and badly wounded. He fled, carving out the Whanganui River as he made for the west coast of the North Island. Meanwhile the smaller Putauaki got as far north as Kawerau; but Tauhara was reluctant to leave and continually glanced back, so that by dawn, when the mountains could no longer move, he had only reached the northern shores of Lake Taupo, where he remains to this day, “the lonely mountain”.
To the local Tuwharetoa people these mountains were so sacred that they averted their eyes while passing and wouldn’t eat or build fires in the vicinity. The tapu stretches back to legendary times when their ancestor Ngatoroirangi came to claim the centre of the island. After declaring Tongariro tapu, he set off up the mountain, but his followers broke their vow to fast while he was away and the angry gods sent a snowstorm in which Ngatoroirangi almost perished before more benevolent gods in Hawaiki saved him by sending fire to revive his frozen limbs.
Tongariro National Park contains some of the North Island’s finest walks, all through spectacular and varied volcanic terrain. The Tongariro Alpine Crossing alone is often cited as the best one-day tramp in the country, but there are many longer possibilities.
During the summer season (typically mid-Nov to April) the Tongariro Alpine Crossing is by far the most popular of the major tramps in the region, and for good reason. Within a few hours you climb over lava flows, cross a crater floor, skirt active geothermal areas, pass beautiful and serene emerald and blue lakes and have the opportunity to ascend the cinder cone of Mount Ngauruhoe. Even without this wealth of highlights it would still be a fine tramp, traversing a mountain massif through scrub and tussock before descending into virgin bush. On weekends and through the height of summer up to seven hundred people per day complete the Crossing: aim for spring or autumn and stick to weekdays. Other ways to avoid the crush are to get one of the early shuttles and keep ahead of the crowds, or turn one long, arduous day into a relaxed two-day experience, dawdling behind the mob and staying the night at Ketetahi Hut.
The Tongariro Power Scheme provides an object lesson in harnessing the power of water with minimal impact on the environment. Its two powerhouses produce around seven percent of the country’s electricity, while the outflows that feed into Lake Taupo add flexibility to the much older chain of eight hydroelectric dams along the Waikato River. Some argue it is unacceptable to tamper with such a fine piece of wilderness, but, while there have been some minor environmental impacts, it is surely better than a nuclear power station.
In fact, if it weren’t for the scale models in visitor centres and the ugly bulk of the Tokaanu power station, only astute observers would be aware of the complex system of tunnels, aqueducts, canals and weirs unobtrusively going about their business of diverting the waters of the Tongariro River and myriad streams running off the mountain slopes, back and forth around the perimeter of the national park, using modified natural lakes for storage. Mount Ruapehu poses its own unique problems: the threat of lahars is ever-present and, after the 1995 eruption, abrasive volcanic ash found its way into the turbines of the Rangipo underground powerhouse, causing an unscheduled seven-month shutdown.