MODERN CANAL DEVELOPMENT IN EUROPE AND
AMERICA Accounts of the canal systems will be found in the articles on the various countries : in this section some modern develop ments in connection with canals and canalized rivers are briefly referred to.
When the era of railways commenced British waterways had attained to the highest point of their prosperity. As the development of the railway system advanced, many of the canal companies were alarmed for the future and sold their under takings to the railway companies, who in
owned 1,138m. out of a total of 3,9o2m. of inland waterways in the United Kingdom; the latter figure including about I,5oom. of canalized rivers. These figures were practically unchanged in 1928. Public interest in the canal problem led to the appointment in 1906 of a Royal Com mission to report on the canals and inland navigations of the King dom. (In England there is a particular meaning attached to the word navigation which implies a canalized river; e.g., the Weaver Navigation, as distinct from an artificial canal.) Its report, pub lished in 1909, was not unanimous and the recommendations of the majority of its members have not since been acted upon by the Government. The most important proposals were, (a) the creation of a Waterways Board, which was to acquire and manage the principal canals of England, and (b) the improvement of the main canal and river routes, linking the Mersey, Humber and Severn estuaries and the Port of London respectively with Bir mingham and the Midlands, to the standard necessary for 1 oo-ton barge traffic or alternatively for 3oo-ton barges. The system of canals proposed to be thus improved came to be known as "the Cross" (fig. 5). (See the Reports, Evidence, etc., Royal Com mission on Canals and Waterways, 1906-09, II vol., particularly Final Report Cd. 4979 [ 1909] •) Comparison of British waterways with those of the continent of Europe often leads to fallacious conclusions unless the impor tant differences, natural and economic, are recognized. In those parts of Europe where inland navigation is most successful, the canals are to a large extent feeders of, or links joining up, large and important rivers either free or canalized ; and further, the average length of haul is immensely greater than in England, the water supply is usually abundant, and the country generally flatter and in many respects less developed. Moreover, the conti nental waterways receive, either directly or indirectly, substantial subsidies from the State and are protected in most countries against railway competition. The improvement of the river Trent, between Newark and Nottingham, a small section of one of the routes proposed for enlargement by the Commission, was, how ever, carried out between 1921 and 1926, and the construction of four new locks on this portion of the river enables 120-ton barges to navigate from the Humber as far as Nottingham.
The Canal du Nord, begun in 1907, and 58 miles long, connects the Sensee canal at Arleux and the Oise canal at Noyon. It is noteworthy on account of its considerable rise and fall, crossing two watersheds, its 19 locks, some of which have a rise of 2 I If t., and two long tunnels. The water supply is obtained by pumping, by means of electricity, from reach to reach the waters of the Sensee, the Somme and the Oise. The minimum bottom width is 33f t., the depth 8* feet. It is the best example of the improved standard type of 3oo-ton barge canal in France. The locks, 2 79f t. by 19.6f t. internally, taking two barges and a tug at once (fig. 6), are provided with cylindrical sluices and single-leaf gates all worked electrically. The works, which were wrecked in the course of the War, were completed in 1923.
The principal inland navigations in Holland are the rivers and canals between the North Sea, the ports of Rotter dam and Amsterdam and the German frontier. Many improve ments have been effected in the Dutch waterways since 1910; those affecting barge canals being in most cases such as will permit the navigation of the large Rhine barges carrying 2,000 tons. The largest of these vessels are about 400f t. in length with a maximum beam of about 46f t. and draught of 12 feet. The locks are constructed with internal dimensions, 85 5f t. by 5 2 2f t., and a depth over sills of I2-1-ft., they accommodate two long barges and a tug in line ahead. Intermediate gates are provided for use in single barge locking. One of these large locks can usually be emptied or filled in about five minutes.
One of the most important of these new or improved water ways is that from Nijmegen to Maastricht. It is made up of the Meuse-Waal canal, completed 1927, the canalized Meuse and the Juliana canal. The standard canal section adopted is r 3of t. bottom width, 196f t. at water level with side slopes of r in 3 and depths of from 11 to 13 feet. Electric pumping plant has been installed to deal with excess of flood water in the canal portions. Five locks have been constructed in a length of about 67 miles of the canalized Meuse. These locks have weirs with navigation open ings about 2ooft. in width which can be used for the passage of barges when the water level is high.
The navigation of the upper reaches of the Rhine above Strasbourg is complicated by clause 358 of the Treaty of Versailles by which France is authorized to build a lateral canal alongside the Rhine between Basle and Strasbourg and to draw water from the river for the production of electric power. Before the War the Swiss had built an inland port at Basle in anticipation of the improvement of the river channel below that town which is normally navigable only during the summer season by barges of small draught. Three distinct methods of providing an improved navigation are possible : (a) improve ment of the river by regulation and deepening, (b) canalization of the river, and (c) the construction of a lateral canal. Swiss and German opinion favoured one or other of the two first alter natives : the French pressed strongly for the last. Prolonged dis cussion ended in 1925 in the approval by the Central Commission of the Rhine being given both to the carrying out of river im provements by Switzerland and Germany and to the construction by France of the lateral canal which must be navigable and as free as the river itself. The first section of the canal, that between Basle and Kembs, was begun by France, with the concur rence of Switzerland, in 1927. This section is probably the most important from the point of view of navigation, as it avoids the Istein rapids below Basle. The canal and its lock will accommo date Rhine barges of over 1,200 tons capacity.
The enlargement of the waterways system connecting the Rhine and the Danube, by way of the Main, was commenced by Germany in 1921, and was (1928) in course of alteration by the improvement of certain existing river and canal navigations and the construction of some new canals. The enlarged waterways are intended for barges carrying from 1,200 to 1,500 tons.
The total length of improved navigable rivers in the United States is now upwards of 23,500 miles. At least 4o distinct and separate rivers have been im proved by canalization. (See Col. E. H. Schulz, U.S. Army, International Congress of Navigation Proceedings, 1923.) Since 1900 an immense amount of improvement of the inland water ways, both natural and artificial, has been accomplished. As a rule, canalization is well inland, the lower and middle reaches of the great rivers being open navigations. For instance, on the Hudson, the first lock is at Troy, 153 miles from the sea; on the Mississippi, at Keokuk 1,461 miles; on the Tennessee,
miles; and on the Missouri there is open navigation to Fort Ben ton, Montana, 3,555 miles from the Gulf of Mexico. The con struction of locked waterways near seaports to connect ocean traffic with inland navigations is comparatively modern. The New Orleans Industrial canal and the Lake Washington canal at Seattle (see below) are examples.
When traffic on American rivers began to be intense, recourse was had to extensive canalization in cases where shallow water and limited flow gave rise to difficulties either seasonal or con tinuous. Among the rivers so improved are the Ohio, with its tributaries, the Allegheny and Monongahela ; the Kanawha, West Virginia ; the Kentucky in Kentucky ; the Cumberland in Ken tucky and Tennessee ; the Tennessee in Kentucky, Tennessee and Alabama; the Black Warrior and Tombigbee in Alabama; the Columbia River in Oregon and Washington, and the Mississippi above Keokuk.
The locks on the Ohio are among the largest on the great rivers of the United States. The river improvements carried out since 1910 include the construction of 5o locks between Pittsburgh and Cairo, a distance of 968 miles. The cost of the improvements exceeded $roo,000,000. Each lock is 60o x I'oft. internally, with depth over sills ranging from 9 to 12 feet. The lift of the majority of the locks varies from 6 to I2ft., but one, completed in 1921, has a lift of 29 feet. A navigable depth of 9ft. is secured through out by the construction of weirs, with movable crests, one at each lock. The movable weirs secure the advantages of open river navigation when the natural depth in the channel is 9ft. or more.
The Keokuk lock, the lowest on the Mississippi, was completed in 1913. In this case the dam was constructed primarily as a part of a hydro-electric power project. The lock, 38oxIeoft. internally, with 7f t. over the sills, has a considerable lift-4i feet. The upper gate is of floating-caisson type and is operated by com pressed air.
Apart from the river improvements effected by the Federal Government, which controls all navigable rivers, several of the States have undertaken canal work ; the most notable instance being the reconstruction, by New York, of the old Erie canal which now forms the New York State barge canal. This work, carried out between 1905 and 1918, at a cost, including branches and terminals completed subsequently, of over $170,000,000, connects the Hudson river at Troy with Lake Erie at Buffalo.
(See N. E. Whitford, History of the Barge Canal of New York State, and the Book of Plans, published by N.Y. State, Albany, 1921-22.) Altogether, including branch canals and the Lake Champlain section, there are 525 miles of canal proper, with 57 locks. Ships and barges up to 3oof t. in length and 44-if t. beam can navigate the canal. Some of the barges using it have a cargo capacity of 2,500 tons. All the locks have a depth of i 2ft. over sills, and the maximum lift in any one is 401 feet. All lock and other machinery is operated electrically and the canal and its terminal ports are equipped in lavish manner with mechanical appliances. There is at Oswego, on this canal, a novel and inter esting system of siphons for emptying and filling the lock chamber. The traffic on the canal, up to 1928, had not justified the expendi ture on its construction.
Since 1910 practically all locks on inland waterways in the United States have been constructed of concrete. No mechanical lifts or inclined planes are in use, and no provision is made at any of the locks for mechanical haul age of vessels through them. Electric locomotives for rack trac tion are, however, employed for towing ships through the locks of the Panama canal. The large majority of the navigable water ways of the States being rivers of very variable flow, the provision of dams or weirs with sluices has usually been necessary in con junction with lock construction, and many of these works are of considerable magnitude. Steel lock gates of the double-leaf mitred type are adopted generally for new works ; but rolling caisson gates are also used for closing many of the river locks, particu larly at the upper ends of wide locks on rivers. The silting up of the caisson chambers has, however, given trouble in some cases; and their use has been abandoned in works carried out since 1916. "Tumbling" or flap gates ("bear trap") hinged on a horizontal axis have also been used in a few instances. Sluice valves are constructed in the lock walls and are frequently of the "butter fly" type, but Stoney gate sluices and cylindrical valves predom inate. The practice of placing sluice valves in the gates has been abandoned. Movable weirs of the Chanoine and needle types were formerly much used, but in the dams and weirs of later construction some form of sliding or hinged sector gates has often been adopted. The Stoney sluice is typical of the first class and the Taintor gate of the second (see WEIR).
The splendid inland navigation system of Canada mainly consists of natural lakes and rivers. Most of the artificial waterways are lateral canals cut in order to enable vessels to avoid rapids in the rivers. The earliest locked canal in America, completed in 1783, was made to avoid rapids on the St. Lawrence river between Lake St. Francis and Montreal. The lateral canals of the St. Lawrence have an aggregate length of about 46m., and afford a means of navigation from Lake Ontario to Montreal for all vessels which can pass the locks, which have usable di mensions of 2 7ox44f t. with a depth of water of 14f t. on the sills (see GREAT LAKES).
