Early history

An early European explorer, Arthur Dudley Dobson, observed Maoris on the north side of the Grey River had a good sized Pa, about where the Cobden quarry is located.^[5] The Maoris had a few huts which were the remains of a fair-sized village, once inhabited by a much larger population.^[6]

The French navigator Jules Dumont d'Urville, sailed along the West Coast of the South Island in 1827 in the warship, Astrolabe and made reference to the prominent, pyramid shaped limestone outcrops at the base of the Rapahoe Range known locally as the 'Twelve Apostles'.^[5]

Thomas Brunner and Charles Heaphy left Nelson in 1846 to explore the West Coast and arrived at the Twelve Mile just north of Rapahoe in a weary state where they were fortunate to meet a group of friendly Māori who supplied them with food and shelter. A party of Māori accompanied them along the beach and across 'Matangitawau Point' (Point Elizabeth) and onto Māwhera River (later named the Grey River) which they couldn't cross for several days due to flooding. Although they gave an unfavourable report of the area on their return to Nelson, only a few years passed before authorities became interested in the small settlement on the north side of the river.^[5]

After James Mackay completed the sale of the West Coast with the Māori Chiefs in 1860, his mission was then to return to Nelson. Even though the Grey River was in mild flood, he and his companions tried to reach the north bank by canoe so they could continue their journey north. However their canoe capsized and was swept out to sea. The party managed to reach the north bank and some days later their canoe was washed up on the north beach.^[7]

The Grey River became the southern boundary of the Nelson Provincial Government. The Superintendent of the time, Alfred Saunders, considered it time to see the potential of this region for himself. Initially he despatched two Wardens, John Blackett and H.W. Barnicoat by sea to inspect the area and report back to him. But then Saunders departed for the area himself, leading a party overland. Both parties arrived at the Grey River about the same time and after inspecting the area and checking the people already in residence, Superintendent Saunders decided it should be given a name. Saunders was a keen follower of English politics and decided he would give the name of 'Cobden' to this place, honouring Richard Cobden.^[7]

The first bridge

In February 1884 tenders were called and the lowest price of £15,000 was accepted from Mr J. M. Watson of Dunedin. The bridge was designed of kauri timber of 6 spans, 109 feet each in length and founded on 5 pairs of cast iron cylinders 53 feet long being 6 feet in diameter at the top and 8 feet at the bottom. These cylinders were filled with concrete.

The kauri was milled in the North Auckland Forests and shipped down from Kaipara by barque and across the Grey bar. The cast iron cylinders were sunk by the compressed air method whereby air was supplied by a huge compressor which delivered all the air necessary to the workmen in their iron wells by means of a strong leather hose, such as firemen use.

The bridge faced serious setbacks in 1885 when two major floods damaged and destroyed the last two cylinders on the Cobden side. However the bridge was finally completed and opened in February 1886. The final cost of the bridge was £18,000 with the Local Authorities contributing £4,500.^[10]

The second bridge

By 1916 the kauri superstructure was showing signs of deterioration and in March 1916 a contract was accepted for its replacement in Australian hardwood from Mr H. Bignall of Greymouth, costing £14,320. This construction was completed in 1920 and boasted a footway capable of having two perambulators pass.^[10]

The new bridge

In 1960 the Road Safety Council made application for a new bridge because of the long delays to traffic. By 1965 traffic counts were showing 4,000 vehicles per day, and this figure was to double over the next 10 years.

Construction commenced in October 1973. Foundations were constructed by building a causeway of gravel out across the river, then sinking large steel cylinders into it to allow the water level to be lowered, while steel H piles up to 85 feet long were driven to the basement limestone. Three piers in the main channel , where the limestone is up to 160 feet below the river bed, were founded on 66 foot long prestressed concrete piles. Fifty five precast prestressed concrete I beams, each weighing 25 tons, were manufactured locally and lifted by crane to span from pier to pier. Hydraulic shock absorbers were incorporated throughout to accommodate earthquake resistance.

During construction, two major floods caused some serious delays, with damage mainly to the temporary causeway. Once completed the bridge measured 910 feet in 11 spans with a total cost of $1.22 million. It was opened on Saturday 9 August 1975 by the Hon. Michael Aynsley Connelly, MP Minister of Works and Development and Chairman of the National Roads Board.^[10]