In the United States, canal building began slowly. Only 161 km (100 miles) of canals had been built at the beginning of the 19th century, but before the end of the century more than 6,437 km (4,000 miles) were open to navigation. With wagon haulage difficult, slow, and costly for bulk commodities, water transport was the key to the opening up of the interior, but the way was barred by the Allegheny Mountains. To overcome this obstacle, it was necessary to go north by sea via the St. Lawrence River and the Great Lakes or south to the Gulf of Mexico and the Mississippi. A third possibility was the linking of the Great Lakes with the Hudson via the Mohawk Valley. The Erie Canal, 584 km (363 miles) long with 82 locks from Albany on the Hudson to Buffalo on Lake Erie, was built by the state of New York from 1817 to 1825. Highly successful from the start, it opened up the Midwestern prairies, the produce of which could flow eastward to New York, with manufactured goods making the return journey westward, giving New York predominance over other Atlantic Seaboard ports. The Champlain Canal was opened in 1823, but it was not until 1843, with the completion of the Chambly Canal, that access to the St. Lawrence was made possible via the Richelieu River.

Meanwhile, Canada had constructed the Welland Canal linking Lakes Ontario and Erie. Opened in 1829, it overcame the 100-metre (327-foot) difference in elevation with 40 locks, making navigation possible to Lake Michigan and Chicago. Later the St. Mary’s Falls Canal connected Lake Huron and Lake Superior.

To provide a southern route around the Allegheny Mountains, the Susquehanna and Ohio rivers were linked in 1834 by a 634-km (394-mile) canal between Philadelphia and Pittsburgh. A unique feature of this route was the combination of water and rail transport with a 60-km (37-mile) portage by rail by five inclined planes rising 426 metres (1,399 feet) to the summit station 711 km (2,334 feet) above sea level and then falling 350.5 metres (1,150 feet) to Johnstown on the far side of the mountains, where a 169-km (105-mile) canal with 68 locks ran to Pittsburgh. By 1856 a series of canals linked this canal system to the Erie Canal.

Meanwhile, the Louisiana Purchase of 1803 had given the United States control of the Mississippi River, and it became the main waterway for the movement of Midwestern produce via New Orleans and the Gulf of Mexico. Developments included the Illinois-Michigan Canal, connecting the two great water systems of the continent, the Great Lakes and the Mississippi. Entering Lake Michigan at Chicago, then a mere village, the canal triggered the city’s explosive growth. Several canals were constructed subsequently to link up with the Erie and Welland canals and the St. Lawrence, and a comprehensive network of inland waterways was established.

Impact of the railways

With the development of rail transport in the 19th century, canals declined as the dominant carriers of freight, particularly in the United States and Britain. In continental Europe the impact was less marked, because the great natural rivers already linked by artificial waterways constituted an international network providing transport economically without transshipment; the terrain was more favourable and the canals larger and less obstructed by locks. Elsewhere canals could not compete with rail. They were limited both in the volume carried per unit and in speed; they were too small, too slow, and fragmented; and the railways, as they became integrated into national systems, provided a far more extensive service with greater flexibility. The canals were further handicapped because they were not, for the most part, common carriers themselves but were largely dependent on intermediate carrying companies. Although transport on the canals was for some time cheaper than rail, the railways gradually overcame this advantage. To modernize and extend the waterways to enable larger boats to ply them, to reduce the number of locks that slowed down movement, and to provide a more comprehensive service all required capital investment on a scale that made the return problematic. The railways exploited the difficulties of the canals by drastic rate cutting that forced many canal companies to sell out to them. In Britain a third of the canals had become railway-owned in the 1840s and ’50s, and many were subsequently closed down. In the United States, half the canals were abandoned. The railways thus succeeded in eliminating their competition and obtained a near monopoly of transport, which they held until the arrival of the motor age.

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The Kiel Canal

The 19th century saw the construction of the Kiel and Suez canals. The former carries tonnage many times that of most other canals. Frequent attempts had been made to make a route from the Baltic to the North Sea and thus to bypass the Kattegat and the dangerous Skagerrak. The Vikings had portaged ships on rollers across the 16-km (10-mile) Kiel watershed, but not until 1784 was the Eider Canal constructed between the Gulf of Kiel and the Eider Lakes. A little more than 100 years later, to accommodate the largest ships, including those of the new German navy, the Kiel Canal was widened, deepened, and straightened, cutting the distance from the English Channel to the Baltic by several hundred miles. Running 95 km (59 miles) from locks at Brunsbüttel on the North Sea to the Holtenau locks on the Gulf of Kiel, the canal crosses easy country but has one unique engineering feature. At Rendsburg, to give clearance to the largest ships, the railway was made to spiral over the city on an ascending viaduct that crosses over itself before running on to the main span above the water.