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THE WELLINGTON FLOOD

Wellington and the Hutt Valley are not usually subjected to serious flooding. The Hutt River has been known to overflow its banks from time to time, and heavy rain may occasionally bring down slips and flood stormwater drains at various places through the two cities, but the flood that took place on December 20, 1976 was the worst since the area was first settled.

Fortunately, the Meteorological office estimates that the amount of rain that fell and caused the flood is unlikely to fall in those amounts again for at least 500 years!

The rain that fell on the evening of December 19 was absolutely torrential. It continued to bucket down the following morning, turning streams into raging torrents. Slips began to fall, completely blocking roads at various places throughout Wellington and the Hutt Valley. Then the floodwater began to rise.

By nine o'clock on the morning of December 20, commuters were being warned over the local radio stations not to use certain roads in the district and, especially, not to try to travel between Wellington and the Hutt Valley. But by then it was too late for many people who had become stranded at their places of work; in shopping areas; or in their cars, cut off by slips and rising floodwaters.

By mid-morning, the road and the railway lines at Petone were completely flooded, and further floods at Ngauranga and Kaiwharawhara had also closed the roads to the Ngaio and Ngauranga Gorges. Suddenly Wellington's road and rail transport systems had become completely cut off from the rest of the country.

The situation at Petone to the north-east of Wellington was absolutely chaotic. The muddy water, flowing into the area like a river, had stranded vehicles. In some cases the water was up to the roofs of small cars, and even quite large trucks and vans were being pushed about by the surging torrent. Luckily, most of the drivers escaped to higher ground before their vehicles became completely flooded.

One man, Eddie Emden, found himself in a particularly dangerous situation. He was trying to move his van to safer ground when the engine cut out and the van was swept on to the railway line by the raging floodwaters.

Mr Emden decided to stay in the van, but the water was almost up to the windows while logs, oil drums, trailers and other debris were being swept past at great speed. He was afraid that at any moment his van might be rolled over or swept into the sea, taking him with it.

Fortunately, a policeman and a former army officer were brave enough to take a rope into the floodwaters. They allowed themselves to be carried by the current down to Mr Emden's van and eventually they were all hauled to safety.

A short distance away, in Petone, a group of workers were forced to climb on to the roof of their factory in order to escape the rising floodwaters. They were rescued by a helicopter that landed them on the Petone overbridge, one of the few places safely above the water level.

The overbridge was normally a bridge over the railway line but, by then, it was more like a bridge over a flooded stream.

But it wasn't only Petone that took the battering. The effects of the deluge were quite widespread throughout Wellington and the Hutt Valley.

At Porirua, in another part of the Wellington district, workers were forced to take refuge on the roof of their factory when the Kenepuru stream burst its banks. They remained there for several hours until they were rescued.

At Johnsonville, many early morning shoppers were surprised to see some shopkeepers trying to mop up the water that was seeping up through the floors of their shops. When they returned to the carpark they found that they were faced with a water problem too - they were completely stranded, with water up to a metre deep surrounding their vehicles.

The centre of Wellington was extensively flooded with drains blocked or overloaded. Shops in the main retail area of Willis Street were damaged by flood waters and in some parts of Lambton Quay, near Parliament buildings, the water reached a depth of several feet.

There was only one fatality caused by the flood, although many people - like Mr Emden - had lucky escapes when they were rescued from vehicles threatened by rising floodwaters or evacuated from houses that were about to be swept away by slips.

The only person to lose his life during the flood was a young boy of three and a half who was at the Guide Hall in the Crofton Downs suburb of Wellington. His mother was one of the parent helpers at a Brownie Camp held in the hall that weekend. After listening to the rain thundering on the roof all night, they awake to find that a stream had flooded in front of the hall, cutting them off from the road. The party settled down to wait for the rain to slacken and the flood to recede.

During the morning the water had been seeping from a bank at the back of the hall and shortly after midday it broke away in a huge slip. A mass of sodden earth crashed on to the back wall, causing it to collapse and burying the young boy beneath it. Eventually, one of the parents at the hall managed to cross the swollen stream to seek help. But when the earth and wreckage was cleared, it was found that the boy was dead.

The emergency services of the cities were stretched to breaking point. Firemen worked for many hours on end trying to pump water from flooded houses, shops, and factories. Police, ambulance drivers, and civil defence volunteers were kept busy rescuing people tapped by slips or rising floodwaters.

Helicopters, including one from the United States Coast Guard Ship "Burton Island", which was visiting Wellington at that time, made many rescues. The New Zealand Army's big four-wheel-drive trucks also proved extremely valuable as they were able to get to places impossible to reach in normal vehicles. The cross-country ambulance from Trentham Army Camp was also used to take two elderly people, who where suffering from hypothermia, to hospital.

Transport in or out of the city was completely cut off. The main trunk railway out of the city was not reopened until 10.45am the following day, and the lines to Johnsonville and the Hutt Valley were even more severely damaged. A bus shuttle service was used to transport passengers to those areas until the lines could be re-opened.

The Ngaio Gorge and the Ngauranga Gorge roads were also closed for a long period until floodwaters subsided at their lower ends and slips could be cleared. For a considerable time the back road through Churchill Drive was the only means of reaching the northern suburbs, and traffic moved at a crawl.

The rainfall at Avalon was recorded at over 130 millimetres in the 24 hours up to 2am on September the 20th. At Belmont School, not far away, there was extensive flooding and large sections of pathway were washed away. It was fortunate the flood occurred during the school holidays, as any children who had attempted to reach school would have been in serious danger.

In Pinehaven and Stokes Valley large trees were brought down by slips, and a number of houses slipped off their foundations. Some Stokes Valley homes were completely destroyed as they crashed over a cliff face when the land slipped away. Numerous houses in low-lying areas had carpet and furnishings ruined as murky water flooded through them. Cars were also destroyed as banks broke away and fell on them or their garages. There were power failures in some parts of the city and telephone lines became jammed due to the number of calls being made.

Many people were stranded in the city by the flood. Hotels were completely booked out and there were still people seeking accommodation in the city at 1.30am the following morning. One city cinema ran all-night movies to entertain the people who could not reach their homes or find accommodation. There was also a run at the shops on such items as soap and toothbrushes as many people had left for work with only the clothes they stood in. In the suburbs, many of those who were forced to abandon their homes had to spend the night with friends or in local halls along with the few possessions they were able to rescue.

It was still raining on the morning of December 21st and exhausted firemen, traffic officers, and council workers were still working flat out to try to cope with the damage. During the emergency there had been a lack of information transmitted over the radio or by other means of communication that would inform people of the situation or provide directions and advice.

Rather belatedly, the national Civil Defence headquarters, based in the basement of the Beehive (in Parliament buildings) moved into action. Many people felt that a State of Civil Defence Emergency should have been declared as soon as Wellington had become isolated by the flood. A State of Emergency had already been declared in the cities of Lower Hutt and Upper Hutt. However, the Mayor of Wellington maintained that emergency services were coping adequately and it was not necessary to declare a State of Civil Defence Emergency.

By December 22, 1976 the worst of the flooding was over and a massive clean-up operation commenced. The total damage in insurance claims and other costs was to reach over $30 million, making this New Zealand's most expensive flood up to that time.

From a helicopter, which flew over the Hutt Valley the following day, huge areas covered by mud and silt could be seen. Men looked like ants as they worked with shovels and high pressure hoses trying to clean up the mess. In some areas, front-end loaders were working on slips or piles of silt, and trucks were parked nearby to transport the spoil away.

From Stokes Valley to Petone and on to the Ngauranga Gorge, a huge brown worm of muddy water was still winding its way to the sea. On the other side of the valley, the swollen Hutt River also resembled a great brown worm as it poured into the harbour. A waterfall of muddy water was also pouring down from the Horokiwi Quarry and helping to discolour the waters of the harbour.

From the air a number of homes in Stokes Valley resembled crushed doll's houses. Fallen trees still blocked several roads and there were a variety of re-brown scars on the hillsides where slips had come down. Bowling greens and tennis courts were coated with silt and the whole area appeared to be covered with a vast blanket of mud.

The heavy rainfall that occurred in Wellington before the 1976 flood was a very rare event indeed and is likely to happen only once, on average, every 500 years. However, this does not mean that it will be 500 years before it could happen again. These are only estimates of how frequently an event is likely to occur on average, and rainfall of similar, or even greater, magnitude could take place at any time in the future.

Floods took place quite frequently in the Wellington area before the city was built. Water flowed from higher ground towards the sea through a variety of natural rivers, streams, and creaks that often formed gullies or gorges, such as those at Ngaio and Ngauranga. Where the land was flat, and wider, more winding streams and rivers were formed. These winding streams and rivers, such as the Hutt River, frequently flooded and changed their course over the centuries.

In fact, the cricket ground at the Basin Reserve is sited on what was once a shallow lake. It used to be drained by a small stream that flowed into the harbour down what is now Cambridge Terrace. At times of heavy rain, streams like these often overflowed their banks and low-lying areas such as Miramar and parts of the Hutt Valley were frequently subjected to flooding. In 1840, the first settlement at Petone - called "Britannia" at the time - was badly affected by flooding. This was one of the reasons the settlement was shifted to the site of Wellington on the opposite side of the harbour.

As bush was cleared and roads and houses developed there was a tendency to redirect many of these natural water courses through underground piping. Stopbanks were built in areas like Lower Hutt that were prone to flooding. A system of storm-water drains was also developed to deal with excessive rain water.

However, stopbanks and drains are all very well under normal conditions, but drains are sometimes unable to cope and stopbanks may be broken or overflow when much heavier than expected rainfall takes place, as happened in Wellington in December 1976.

Despite the tremendous effort and heroism of many individuals, the 1976 Wellington flood showed what disruption could be caused by Mother Nature, and how poorly prepared the cities in the Wellington district were to cope with such an emergency.

author: Kevin Boon

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