It was Edward Dobson senior in 1866 who started the first civil engineering project around the Waimakariri River. As a provincial engineer in Canterbury he ordered to quickly cut through the rock and build a road that soon would connect both sides of Arthur's Pass.
In 1887, New Zealand searched for a transport alternative between Greymouth and Christchurch which resulted in the construction of the transalpine railway - "The Midland Line". As the rails from east and west gathered around Arthur's Pass, a railway tunnel needed to be constructed to connect both ends. It took 15 years, to complete the Otira Tunnel on 4 August, 1923. The tunnel is 8.5 km long and back then, it was considered as the longest tunnel in the world.
The latest project is State Highway 73, "The Great Alpine Highway". This road leads 231 km from Hokitika in Westland to Christchurch in Canterbury. In Arthur's Pass National Park, the highway runs through difficult terrain that experiences rockfall hazards and small seismic activity regularly. That is the reason why civil engineers constructed the Otira Viaduct in 1999. It has a total length of 440 m, measures eight metres in width and has a maximum height of 35 m above ground.