RIVER PORTS IN THE MAKING.

Dominion, Volume 6, Issue 1859, 19 September 1913, Page 3

RIVER PORTS IN THE MAKING.

ENGINEERING TRIUMPHS.

OBJECT LESSONS ABROAD^

AN INTERESTING INTERVIEW.

By the Manuka, which arrived from Sydney on Wednesday, Mr. C. H. Howorth, engineer to the Wanganui Harbour Board, returned from an eight months' holiday trip to .the United Kingdom and tlie Continent. Mr. Howorth, as engineer of the works which have so greatly improved tho approach to the Wanganui River, was particularly interested 111 harbour works at, Home, and made it his business to thoroughly inspect the work which had been and was being done in the great river ports of the United Kingdom. He surprises 0110 by saying that the River Clyde, which wo, through tho frequent mention of its name, aro apt to imagine a great waterway, is absolutely in&ignificant as a river compared with the Wanganui, and was only a small river in the middlo of the eighteenth century, when tho work of extending its uses was recommenced. Mr. Howorth w<\s conducted all over the works . from Broomelaw Briclg# (in the harbour proper) to Renfrew. The Clyde has a tidal current of from four to live miles, is 500 ft. wide, and had an average low-water depth of 23ft. 6in.—which the Clyde Navigation Trust is at present endeavouring to iucrea.se to 25ft. Insido the line of tho river banks were wet and dry docks, the largest of which was at Rothesay. On tho Clyde they build the dock walls on the dry land, just as the foundation walls of a house aro built, digging out the earth with dredges. There were seven miles of dock walls up the river. The river was only 370 ft.. wide at Kelvin, but there they were working on a. scheme that would give an even width of 450 ft. To do that they had to remove tlie groins erected years before ill connection with old works, and what was worse, had to purchase the land behind the groins, which had gone into private ownership. Mr. Howorth mentioned that fact as important in order that bodies controlling river, ports should ta.ke every precaution, and look well ahead when dealing with riverbank lands. The improvements that have been made on the Clyde havo meant the removal from the harbour proper of 60,000,000 cubic yards of spoil, nnd that had only given tlieni a lowwater depth of 23ft. Gin., which meant that the larger vcssels'had to be floated into the docks at high-water, and the closing of tho dock-gates kept plenty of water under their keels. It was only the comparatively smaller craft that could work the river at low water.

"The Clyde," said Mr. Howorth, "was never nearly so good a river as Wanganui is to-day, aud yet at a large expenditure of money they have been able to make it one of the most important ports in the Kingdom, which only shows what can bo done. As a river the Wanganui is magnificent in comparison with the Clyde, besides havr ing natural advantages which the engineers havo not had on the Clyde. "The Mersey, with Liverpool on its banks, is another river tliat is insignificant compared with the Wanganui, with the latter's ideal tidal range and wonderful natural scour which does the work that had to be dono by dredges in all tho river harbours at Home. At Liverpool and Birkenhead tliore are hoV fewer than 582 acres of docks and 36 miles of quays —G3 wet docks and 19 "raving docks. On the Liverpool sido tho wliolo monotonous extent of tho docks are conncctcd up with an overhead railway, and looking from the windows one can look down on the decks of the Maurotania, Lusitania, and any of tho Atlantic greyhounds which happen to bo in port. Tho Mersey is noted for its great tidal range (2tift.) and bar (of sand) which had to be continually dredged. This was attended to by a dredge of 10,000 tons capacity, and it was removing tho material from tho bar at a cost of 3d. per ton —probably tho cheapest dredging rate in the world. As a comparison tho cheapest rate in Now Zealand is 2d. per ton at Westport. The cost in Wellington is about 7}d. per ton. Tho means which bring about this low cost is the great. capacity of the dredge (which loses considerably less timo in shifting than smaller dredges) nnd tho lower cost of coal and. labour. But it is the cheapest dredg-' ing rate in England/

The English Tyrw, "The Tync," continued Mr. Howorth, "is a river that- much resembles Wanganui in certain features. It is on record when there was only oft. of water on tho bar at low water, a depth which existed on the Wanganui bar before any training walls were built. Now they have 20ft. of water at low tide on the Tyne bar, and from 30ft. to 35ft. at high water, and vessels can leave at any state of tlie tide providing the weather is suitable. This marvellous change, which has made Nowcastle-on-Tyne the third shipping port in tho United Kingdom has been effected by dredging, and tlie erection of moles at the river mouth. These havo been erected with a narrow entrance, opening out inside to provide a large wave basin. The engineer assured me that in the height of a north-easterly gale he had measured waves 26ft. in height from trough to crest, whereas in Wanganui our waves aro only oft. in height at the worst. That means that where an enormous monolith is needed by way of moles at the Tyne,' we can do with a low training wall, and whereas the cost of the erection of the Tyne moles was about £110 per foot, the cost would be only a fifth of that in Wanganui. . ''So it will be evident to anyone," said Mr. Howorth, , "that whilst at Homo they have had to cope'with terriblo difficulties to make good river ports, we have at Wanganui an ideal river .ind situation to found a great port upon. Mark tho expense of tlie works on the Tyne. Hie harbour improvements havo meant the removal of 130,000,000 tons of spoil at 7d. per ton, costing £3,750,000. The port authorities have a floating plant that cost £400,000, and a fixed plant which cost £500,000. Its total debt is £4,750.000. Whilst I was there tliev were building new yards for the Armstrong, Whitworth Company, which meant the removal of 4,000,000 tons of spoil well out to sea. It- was a colossal work, but it paid. This enterprise has made Newcastle-on-Tyno a wonderful port in many ways, and demonstrated what can be done in the face of tremendous difficulties." Mr. Howorth also mado an inspection of tho harbour works at Maas (on the Kliino), Weser, Genoa, Marseilles, and Naples. Port Said, too, was interesting on account of the gradual but continual spread of tho mud of tho Nile, necessitating constant dredging. In the Mediterranean thero was, no scour to move the mud by natural means, and it nil had to bo'dredged and emptied miles out at sea.