Orange-Fish River Tunnel, South Africa - 1972 

Produced by the National Film Board of the Republic of South Africa - 1972.
This film looks at how to build concrete lined tunnels using the Orange-Fish tunnel as an example.
The construction of the Orange-Fish Tunnel made possible the irrigation of thousands of hectares of additional land in the Eastern Cape of South Africa, diverting water from the Orange River to the Great Fish River.
With a length of 83 km, the 5,35m diameter tunnel was the longest continuous enclosed aqueduct in the southern hemisphere and the second-longest water supply tunnel in the world.
It was engineered in association with Messrs Keeve Steyn and Partners of Johannesburg for the Water Affairs Department of the South African Government.
Former Halcrow senior partner, Sir Alan Muir Wood, the "father of modern tunnelling" worked on many of the world's leading tunnel projects, including the Orange-Fish Tunnel.
Interesting fact:
The Orange River was named by Robert Jacob Gordon after the Dutch Royal House.