The

Ngauranga Ngauranga is a suburb of New Zealand's capital city, Wellington, in the lower North Island. Situated on the western bank of Wellington Harbour, it lies to the north of the centre of the city. The name comes from the Maori-language ''ngā ūra ...

Gorge A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

is in the

Wellington Region Greater Wellington, also known as the Wellington Region (Māori: ''Te Upoko o te Ika''), is a non-unitary region of New Zealand that occupies the southernmost part of the North Island. The region covers an area of , and has a population of T ...

of New Zealand.

State Highway 1 The following highways are numbered 1. For roads numbered A1, see list of A1 roads. For roads numbered B1, see list of B1 roads. For roads numbered M1, see List of M1 roads. For roads numbered N1, see list of N1 roads. For roads numbere ...

runs through the gorge, a vital link between central

Wellington City Wellington City Council is a Territorial authorities of New Zealand, territorial authority in New Zealand, governing the country's capital city Wellington, and ''de facto'' second-largest city (if the commonly considered parts of Wellington, ...

and its northern suburbs and Porirua City and the

Kapiti Coast The Kapiti Coast District is a local government district of the Wellington Region in the lower North Island of New Zealand, 50 km north of Wellington City. The district is named after Kapiti Island, a prominent island offshore. The pop ...

; it is the main route north out of Wellington. It is long and has a grade of approximately 8 percent. Sixty-five thousand vehicles a day travel through it, and it connects the

Wellington Urban Motorway The Wellington Urban Motorway, part of SH 1, is the major road into and out of Wellington, New Zealand. It is 7 km long, ranges from three to seven lanes wide, and extends from the base of the Ngauranga Gorge into the Wellington CBD. Fro ...

with the

Johnsonville–Porirua Motorway The Johnsonville–Porirua Motorway is a motorway in Wellington, New Zealand. The majority of the motorway forms part of State Highway 1, the main route of traffic in and out of the city, with the northernmost , formerly part of SH 1 until 7 Dec ...

. The name is derived from the former Ngā Hauranga pā at the foot of the gorge. Its spelling was simplified after the

second world war World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

Formation

A Ngahauranga Road Association was formed in late 1850 because residents of Johnsonville and places further north found the road up the Ngaio Gorge, now the Old Porirua Road, too steep and dangerous. The road had been built privately for access to a farm with its homestead within Trelissick Crescent, Ngaio. A Fighting Fund was established and a deputation sent to the governor of the province who advised the matter would be referred to the Surveyor General. The residents regarded the matter to be as important to Wellington as the tunnel through the

Port Hills The Port Hills are a range of hills in Canterbury Region, so named because they lie between the city of Christchurch and its port at Lyttelton. They are an eroded remnant of the Lyttelton volcano, which erupted millions of years ago. The hi ...

was to Christchurch.Tawa Historical Society Incorporated
Old Porirua Road's place in history. Accessed 25 February 2019 Work began in 1853 and by the end of 1855 a distance of 946 metres4 furlongs and 7 chains had been formed and metalled. That was the easy part. The next year saw another 3,340 metres2 miles and 6 chains added but that section was only a

bridle path A bridle path, also bridleway, equestrian trail, horse riding path, ride, bridle road, or horse trail, is a trail or a thoroughfare that is used by people riding on horses. Trails originally created for use by horses often now serve a wider r ...

. The Ngahauranga Road built to coach road standard was officially opened 4 June 1858 when his Honour, the Superintendent, led by the band of the 65th drove a four-horse phaeton along the line starting from the beach at Ngahauranga.

Centennial Highway

The road up the gorge was transformed between July 1938 and November 1939 as an extra part of the Wellington to Paekakariki project later dubbed the Centennial Highway. In June 1938

Bob Semple Robert Semple (21 October 1873 – 31 January 1955) was a union leader and later Minister of Public Works for the first Labour Government of New Zealand. He is also known for creating the Bob Semple tank. Early life He was born in Sofala, New ...

, Minister of Works, announced the administration of Ngahauranga Gorge would leave Wellington City and Suburban Highways Board and join the new system of State Highways. He said "Motoring mishaps, some more serious than others, are not uncommon, due principally to the tortuous nature of this road and the density of traffic which amounts to between 3000 and 4000 vehicles per day. . . . Briefly the intention is to completely re-align and re-grade the road through the Ngahauranga Gorge so as ultimately to provide for four lanes of traffic." On commencement of the project the new Minister "symbolised the new administration's optimism and the power of machinery over the picks and shovels by getting into a bulldozer and wrecking a pile of wheelbarrows". The Ngauranga Gorge four-lane highway was officially opened on 4 November 1939. ;Statistics

:Length: 1¾ miles (2.8 kilometres) :Earthwork: ::600,000 cubic yards (458,733 m³) :Culverts: ::10ft arched culvert 400ft (122 m) ::10ft flat-top culvert 70ft (twin) (21 m) ::60in and 72in conc. pipe 2920ft (890 m) ::12in pipe 3950ft (1204 m)

:Kerbs 36960ft (11265 m) :Sealing 47520 yds² (39733 m²) :Footpath paving 7920 yds² (6622 m²) :Stock tracks 70 chains (1408 m) :Sewer and water main 3968ft (relay) (1210 m)

:Water drives 1240ft (378 m) :Stream diversions, concrete flume ::and rock cut 47 chains (945 m) :Sub-soil drains 6930ft (2112 m) :Sumps 47

Motorway

The first section of the

opened in December 1950 but traffic was funnelled through Johnsonville until a bypass was completed towards the end of the 1950s joining the Gorge's four lanes to the Motorway. A junction controlled by lights remained between the two highways until the end of the 20th century. During the 1960s the road through the gorge was widened from four to six-lanes. This required considerable excavation and the rock removed went into harbour reclamation for the construction of the

completed in 1969. The

Ngauranga Interchange The Ngauranga Interchange at the foot of the Ngauranga Gorge is a major interchange in the suburb of Ngauranga, in Wellington City, New Zealand. The Ngauranga interchange connects State Highways A state highway, state road, or state route ...

flyover joining State Highways 1 and 2 was finished in 1984. The Newlands Interchange, at the top of the gorge, was constructed in 1997–98 to replace the simple junction controlled by traffic lights, which caused a large amount of congestion. Further excavation and widening of the gorge was required to construct the interchange and a short uphill section between Abattoirs Road the Newlands exit was widened to four uphill lanes. The

North Island Main Trunk The North Island Main Trunk (NIMT) is the main railway line in the North Island of New Zealand, connecting the capital city Wellington with the country's largest city, Auckland. The line is long, built to the New Zealand rail gauge of and ser ...

railway crosses the bottom of the gorge via an overbridge between the Tawa No 1 and Tawa No 2 Tunnels of the Tawa Flat deviation. There is an industrial area and some retail outlets at the bottom of the gorge, where there was previously an

abattoir A slaughterhouse, also called abattoir (), is a facility where animals are slaughtered to provide food. Slaughterhouses supply meat, which then becomes the responsibility of a packaging facility. Slaughterhouses that produce meat that is no ...

. Another abattoir and a quarry are part way up the gorge.

Maintenance

On 11 July 2017 the southbound (down) lanes were closed by a rock slip about mid-day (until 6 am the next day) due to a "debris avalanche" on a modified slope above the lanes.

Notes

References

External links

Ngauranga Gorge 2015Photos of road construction in 1938/9
* * * * {{coord, -41.238873, 174.806291, region:NZ_type:landmark, display=title Wellington City Canyons and gorges of New Zealand Rock formations of the Wellington Region State Highway 1 (New Zealand)