Ngauranga Gorge

The Ngauranga Gorge is in the Wellington Region of New Zealand. State Highway 1 runs through the gorge, a vital link between Wellington City and the Kapiti Coast and the main route north out of Wellington. It is 2 kilometres (1.2 mi) 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 with the Johnsonville–Porirua Motorway.

The road up the gorge was upgraded between 1936 and 1939 as part of the Centennial Highway project from Ngauranga to Paekakariki. During the 1960s the road through the gorge was widened from four to six-lanes. This required considerable excavation with the rock removed used for harbour reclamation for the construction of the Wellington Urban Motorway.

The Newlands Interchange, at the top of the gorge, was constructed in 1997–98 to replace a 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 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 with some retail outlets at the bottom of the gorge, where there was previously an abattoir. There are an abattoir and quarry part way up the gorge.

The name is derived from the former Nga Hauranga Maori settlement at the foot of the gorge.

The 2-kilometre (1.2 mi) cycle up the gorge is a daily mini-endurance test for many cycle commuters at the end of their working day. However the steep downhill for undertaken by cycle commuters in the mornings represents a relatively dangerous and thrilling start to their day. Cyclists regularly exceed 90 kilometres per hour (56 mph) while vehicular traffic tends to remain around 80 kilometres per hour (50 mph) due to the presence of a speed camera situated part way down the gorge which is set at 80 km/h.

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