£4.6m Project Gives New Berths, Sheds

Press, Volume CIII, Issue 30610, 28 November 1964, Page 20

£4.6m Project Gives New Berths, Sheds

The eastern harbour extension of the Lyttelton Harbour Board which has given Lyttelton a neew look is a £4.66 million project which will open up the port to much greater use by road transport as well as providing additional railway facilities. In brief, the project is a marginal quay about 3500 ft long designed for the largest class of vessels trading with New Zealand. The quay will be served by three steel-framed single-storey transit sheds. Each will be 600 ft long and 120 ft wide, fronting the berthage with a 65ft wide apron. When they are completed the sheds will provide more space than all the sheds at the Christchurch railway yards.

On the apron there are three lines of railway tracks and 12 five-ton fullportal cranes spanning the trades. On the landward side of the sheds there are two railway tracks and a 100 ft roadway, which in turn fringes an open storage area some 180 ft wide. The whole of the area had been formed by reclamation from the sea. The berthage is protected by a breakwater arm projecting about 700 ft from the berthage line at its eastern end.

The new berthage plan is a radical , departure from that of the existing harbour, which was built in the 1860’s and modernised from time to time, and has finger piers. About 61 acres of additional flat land have been made. This comprises 40 acres reclaimed with rock fill, 1 nine reclaimed with clay overburden from <the quarry and 12 acres of quarry floor. Previously the cliffs rose sheer up from the sea to form a fringe of hills rising to an average of 1200 ft above sea level. Because of the flatness of the bed in the harbour and the lack of beaches along its sides, the waves roll in almost unchecked; but this was not the greatest problem that had tb be faced—it was the quality of the sea bed itself. Another article describes the difficulty and the exjhaustive tests that were

made before the board embarked on the actual project. As well as this there was a long period of checking wave action, which is almost perpetual in Lyttelton harbour because of its flat bed. Across its width the depths are even and longitudinally it has a fall of only six feet in a nautical mile. The waves come in from the east with no refraction from the usual variable harbour bed. Wave Heights By an electronic device lent by the Department of Scientific and Industrial Research, and sunk in the harbour, engineers measured the heights and lengths of all waves. The worst waves from the east were 12ft high and between 300 and 350 ft in length in the experimental period. The “significant” height of the waves was 6.4 ft.

Calculations showed that the highest wave in a south-west gale would be 4.5 ft.

Over the investigations years the harbour was never dead flat on the surface. In no year was there more than two periods when the waves had been only three inches high, and in some years only one such period was recorded. Road To Quarry

When the board was given the green light for its scheme its first task was to build an access road down a precipitous cliff to reach the site of the quarry.

The first of the rock fill was quarried and placed in September, 1957. It was the first of four million cubic yards of fill dumped into the harbour.

As the rock was dumped it set up waves of mud which was dredged out by the two dredges one bought specially for the work —and taken to dumping sites. All the mud dredged has been deposited inside the heads, and wave action has carried all but an infinitesimal amount out to sea.

The mud was dumped from half an hour after high water until low water in Gollans Bay and for the rest of the day dumping was done, according to tides, in either Little Port Cooper, just inSide Adderley Head, or Camp Bay, both on the southern side of the harbour.

Before the dumping sites were chosen tests were made, including the study of dyes on the sea, and the tide movement proved that the mud was carried out to sea. The engineers had all the data to confound the anti-harbour-dumping proponents who argued that the policy caused shoaling in the upper reaches of the harbour and in the channel.