Beginning shortly below Tekrit there are indications of considerable canalization, both for the purpose of irrigating country remote from the river, and also of shortening the course of the river for navigation.
Shortly below Kut-el-Amara all traces of ancient canalization on the east side vanish, and it would appear as though much of that region, now largely under water at flood time, constituted an inland sea.
The fact also that many of the most ancient of these ruins, like Ur, Lagash (Sirpurla), Larsa, Erech, Nippur, Sippara and Babylon, were situated on the banks of the great canals would indicate that the control of the waters of the rivers by a system of canalization and irrigation was one of the first achievements of civilization.
This ancient system of canalization was inherited from the Persians (who, in turn, inherited it from their predecessors), by the Arabs, who long maintained it in working order, and the astonishing fertility and consequent prosperity of the country watered by the Euphrates, its tributaries and its canals, is noticed by all ancient writers.
Although very little of the coast belt is actually swampy, a kind of natural canalization connects many of the rivers at their mouths with each other, though some of these connecting creeks are as yet unmarked on maps.
A scheme was set on foot for the improvement by canalization of the Cape Fear river above Wilmington under a Federal project of 1902, which provided for a channel 8 ft.
In 1901 the Austrian government laid before the Reichsrat a canal bill, with proposals for works estimated to take twenty years to complete, and including the construction of a canal between the Oder, starting at Prerau, and the upper Elbe at Pardubitz, and for the canalization of the Elbe from Pardubitz to Melnik (see Austria: Waterways).
The alterations made of late years consist of three systems of works: - (r) The canalization of the main stream (4 m.) at Breslau, and from the confluence of the Glatzer Neisse to the mouth of the Klodnitz canal, a distance of over 50 m.
Another project, born at the same time, is one for the canalization of the upper course of the Oder.
Weirs are essential for raising the head of water for water-wheels at mills, and for diverting some of the flow of a river into irrigation canals; but they have received their greatest and most varied extension in the canalization of rivers for navigation.
The trade of the town is facilitated by the canalization of the Scarpe, the basin of which forms the port.
Size between Berlin and Stettin; for improving the waterwal betweell the Oder and the Vistula, so as to render it capabb of accommodating vessels of 400 tons; and for the canalization of the upper Oder.
In addition to this, however, a large number of smaller works were undertaken, such as the canalization of the Main from Frankfort to the Rhine; and a new canal from the Elbe to LUbeck.
These public works were chiefly a canal from the Danube to the Oder; a ship canal from the Danube to the Moldau near Budweis, and the canalization of the Moldau from Budweis to Prague; a ship canal running from the projected Danube-Oder canal near Prerau to the Elbe near Pardubitz, and the canalization of the Elbe from Pardubitz to Melnik; a navigable connexion between the Danube-Oder Canal and the Vistula and the Dniester.
Rumania has no canals, and the canalization of its rivers is impeded by drought and floods.
In both these cases the natural maximum discharge is somewhat diminished by the storage produced by artificial canalization of the rivers.