Holland, the land of dykes and ditches, is completely cut up into small islands by its extensive system of canals, which cross and interlace each other like the threads of some large fishing net. Owing to the level condition of the country, the construction of a canal involves but comparatively little labour and expense, and many of them are used as substitutes for public highways, while in the winter, their frozen surfaces offer convenient roads for skaters. The North Holland canal was, until recently, the finest work of its kind in Europe, and was built during the years 1819-23, at a cost of 950,000l. Since not only the surface, but the beds of many of these canals are above the level of the land, drainage is a matter of great importance, and is effected by means of windmills working pumps.
Phillips[87] speaks of Holland as being intersected by innumerable canals. “They may,” he says, “be compared in number and in size to our public roads and highways, and as the latter with us are continually full of coaches, chaises, waggons, carts, and horsemen, going to and from the different cities, towns, and villages, so on the former, the Hollanders, in their boats and pleasure barges, their breckshuyts and vessels of burden, are continually journeying and conveying commodities for consumption or exportation, from the interior of the country to the great cities and rivers. An inhabitant of Rotterdam may, by means of these canals, breakfast at Delft or the Hague, dine at Leyden, and sup at Amsterdam, or return home again before night. By them, also, a most prodigious trade is carried on between Holland and every part of France, Flanders, and Germany.” The same author declares that the 400 miles of inland navigation open in Holland in his time, yielded an average income of about 625l. per mile, which he declares to be, “almost beyond belief.” What would he have thought had he lived in our time, and seen canals producing an income of 30,000l. to 40,000l. per mile?[88]
The Haarlem Canal was constructed about fifty years ago, for the purpose of draining the Meer or lake of that name. This lake had been formed by an inundation in the end of the sixteenth century, and in the beginning of the eighteenth century it had covered an area of 45,000 acres. Seeing that the lake was gaining upon the land, it was resolved to take effectual means for draining it. This course was precipitated by two furious hurricanes, one in November 1836, which drove the waters of the lake upon the city of Amsterdam, and another in December of the same year, which submerged the lower parts of the city of Leyden. The first step incidental to draining the lake—a work which was undertaken by the Government in 1839—was to dig a canal round about it for the reception of the water, and to accommodate the great traffic which had hitherto been carried on by its means. This canal was made 38 miles in length, 130 feet wide on the west side, and 115 feet on the east side of the lake, and 9 feet deep. All the inlets into the lake, were then closed by large earthen dams; and various works were executed to facilitate the flow of water into the sea. These preliminary works occupied till 1845. To give some idea of the magnitude of the undertaking, it may be mentioned that the area of water enclosed by the canal was rather more than 70 square miles, and the average depth of the lake was 13 feet 1·44 inches. The water had no natural outfall, being below the lowest possible point of sluiceage, and, including rain water, springs, &c., during the time of drainage, it was calculated that probably 1000 million tons would have to be raised by mechanical means. After drainage, too, the site could only be kept dry by mechanical power, so that the annual drainage might amount to 54,000,000 tons, to be raised on an average 16 feet, and it might happen that as much as 35,000,000 tons of that amount would have to be raised in one month.
The North Sea Canal was constructed for the purpose of facilitating the navigation of the Zuyder Zee, which, by reason of its numerous shallows, was very intricate and difficult, and in order that vessels might avoid the Pampus—a bank that rises where the Y joins the Zuyder Zee, and formerly compelled large vessels to load and unload a part of their cargoes in the roads. These obstacles frequently detained vessels for as much as three weeks.[89]
M’Cullough spoke of this canal as “the greatest work of its kind in Holland, and probably in the world.”[90] It was begun in 1819, and completed in 1825. The length of the canal is about 50½ miles; the breadth at the surface, 124½ English feet, and at the bottom 30 feet, while the depth is 20 feet 9 inches. It is a tide-level canal, and is provided with two tide-locks at each end. Intermediately, there are two sluices, with flood-gates. The locks and sluices are double. The canal is crossed by about eighteen drawbridges. The cost of the undertaking was about million sterling.
At the further end of the canal, at Niewdiep, a harbour was constructed, which has been very much frequented by the shipping of Amsterdam. About eighteen hours were formerly occupied in towing ships from Niewdiep to Amsterdam.
The Amsterdam Ship Canal.—The Amsterdam Ship Canal, designed by Mr. Hawkshaw, and Heer J. Dirks, of Holland, is a gigantic example of engineering compressed within a limited extent. The burgesses of Amsterdam had spent millions in improving the access to that great commercial port—first, on long previous operations in the Zuyder Zee, and, subsequently, on the North Holland Ship Canal, which stretches nearly due north from their city to the Helder, between which point and the Texel Island opposite is the entrance from the North Sea, which was then the only available channel for large vessels.
The exigiencies of their trade calling imperatively for further improvements, the engineers furnished them with the design for a new ship canal, which reduces the navigable distance to 15½ miles, on a course about west from Amsterdam to the North Sea, available for larger vessels than formerly entered the port—and has provided a new harbour on the coast, with an area of 250 acres, bounded by breakwaters formed of concrete blocks set in regular courses, with 853 feet of entrance between the pier heads, and 26¼ feet minimum depth of water. The width of the sea canal is 197 feet at the surface, and 88 feet at the bottom; minimum depth, 23 feet; the locks are 59 feet wide, and of proportionate length.
There are three locks or entrances at the north end of the canal from the new harbour. Eastward, and below the city and wharves of Amsterdam, there is an enormous dyke to shut out the Zuyder Zee, pierced with three locks, besides sluices. These are built upon such a lake of mud as to require nearly 10,000 piles in their foundation. Thus the canal is approached by locks at each end, not for the purpose of locking up, but for locking down, as the surface water of the canal has to be kept twenty inches under low-water mark. To accomplish this, in addition to the locks and sluices, that can only avail at low tides, pumping power was required at the dyke, which bars out the Zuyder Zee. The three large centrifugal pumps by Messrs. Eastons, Amos, and Anderson, were constructed to lift together 440,000 gallons of water per minute. The works on this canal took nearly ten years to complete. They included the construction of branch canals to the several towns and ports on the borders of the lakes, which, although of smaller sectional area, exceeded the sea canal in their total extent. Mr. Vignoles, in his Presidential Address to the Institution of Civil Engineers,[91] from which most of the above particulars are taken, has stated that the Amsterdam Ship Canal resembled the Suez Canal, in passing through large muddy lakes, similar to Lake Menzaleh. ([See Suez Canal]).
The ship canals communicating with Rotterdam are described by a recent writer[92] on the subject as follows:—