An engineering marvel...the Otira Viaduct
There is a marvel of engineering technology located right in the heart of one of our National Parks. It is the Otira Viaduct which passes high over the Otira River Valley on State Highway 73 between Arthurs Pass Village and Otira.
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| The Otira Viaduct in Arthurs Pass NP |
Over 440 meters long (1440 feet) and 45 meters high it crosses an area of unstable land and was one of the largest and most expensive local engineering projects of the early 1990's.
A potted history of the Otira-Arthurs Pass Highway:
The road over Arthurs Pass to Otira has always been problematic...it is a high alpine area with massive rainfall events, steep difficult terrain and frequent and large earthquakes. This has made maintaining the route over the pass very difficult to achieve.
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| Map: Otira Viaduct...dotted line was the old road...now a tramping track |
One particular problem was always the massive gravel slips just over the pass and coming down off Hills Peak/Mt Stuart between Pegleg Point and Candy's Corner. This is an active scree slope which frequently slipped over the road every time there was a major storm or a large earthquake. The transport authorities spent many millions each year keeping this section clear.
A trip over this road section was always a sphincter clenching experience...it was winding, narrow and heinously steep. Many was the older English car that cooked an engine climbing the switchback road.
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| Hills Peak and Mt Stuart dominate the area around the Viaduct |
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| SH73 winds over Arthurs Pass into the Otira River Valley |
By the mid 1980's the authorities had enough and tendered a project to build a permanent solution to this tricky roadway. The winning tender was for a massive elevated viaduct from near Deaths Corner to a point further down the Valley. This would cut out the whole problematic section of the existing road and make maintenance of this vital transport route easier and more secure.
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| Silver Surfer at the Otira Viaduct carpark |
The project took over 6 years to complete and cost nearly $2 billion dollars but was ultimately successful. It featured many new techniques not previously used in New Zealand and provided a blueprint for similar projects right around the country.
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| View down the Otira River Valley from the lookout |
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| The scree slopes coming off Hills Peak/Mt Stuart, Arthurs Pass NP |
The builders had to contend with brutal conditions especially during the harsh winters which stretched the project out past its intended finishing date. The population of both Arthurs Pass and Otira swelled with the workers constructing the viaduct as they were the closest places they could be housed. After many years of hard work they finished the viaduct in 1994 and it opened to general use.
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| You can see how rough the Otira river Valley is... |
The Otira Viaduct has received many accolades and awards and has secured access across this formally difficult section of the highway.
A great viewpoint...
Once the viaduct was completed there was no need for the old road so the approaches on the Arthur's Pass side were turned into a magnificent lookout point. There is a sign posted turn off at the old Deaths Corner with views right down the Otira River Valley. From the lookout you have an unobstructed view of the Otira Viaduct.
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| Closer view of the Otira Viaduct |
There are two fine fenced off lookouts here and both have good views down to the viaduct, Otira River and down the Otira Valley. In fine weather or rain they provide magnificent views of this rugged section of the park.
A word of caution though...do not cross the fences...there are significant drops from the lookout and a fall from here would not be good for your health.
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| Silver Surfer at the Otira Viaduct on a rainy day |
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| Mist cloaks the mountains above the Otira River Valley |
The lookout is awesome in fine or wet weather and if you are lucky you will be entertained by the antics of Kea who live in the local area. They will happily dismantle your car/boat/motor bike if you leave them unattended for too long.
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| Native Kea at the Otira Viaduct Lookout |
It was a marvel of engineering when it was built and it is still one of the most difficult and expensive roading projects in New Zealand history. Don't pass it by on your next trip over Arthurs Pass but stop and have a gander.
You Tube: Otira Viaduct Lookout
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