Oder

Oder (Lat. Viadua; Slavonic, Vjodr), a river of Germany, rises in Austria on the Odergebirge in the Moravian tableland at a height of 1950 ft. above the sea, and 14 m. to the east of Olmiitz. From its source to its mouth in the Baltic it has a total length of 560 m., of which 480 m. are navigable for barges, and it drains an area of 43,300 sq. m. The first 45 m. of its course lie within Moravia; for the next 15 m. it forms the frontier between Prussian and Austrian Silesia, while the remaining 50o m. belong to Prussia, where it traverses the provinces of Silesia, Brandenburg and Pomerania. It flows at first towards the south-east, but on quitting Austria turns towards the north-west, maintaining this direction as far as Frankfort-onOder, beyond which its general course is nearly due north. As far as the frontier the Oder flows through a well-defined valley,. but, after passing through the gap between the Moravian mountains, and the Carpathians and entering the Silesian plain,, its valley is wide and shallow and its banks generally low. In its lower course it is divided into numerous branches, forming many islands. The main channel follows the left side of the valley and finally expands into the Pommersches, or Stettiner Haff, which is connected with the sea by three arms, the Peene, the Swine and the Dievenow, forming the islands of Usedom and Wollin. The Swine, in the middle, is the main channel for navigation. The chief tributaries of the Oder on the left bank are the Oppa, Glatzer Neisse, Katzbach, Bober and Lausitzer Neisse; on the right bank the Malapane, Bartsch and Warthe. Of these the only one of importance for navigation is the Warthe, which through the Netze is brought into communication with the Vistula. The Oder is also connected by canals with the Havel and the Spree. The most important towns on its banks are Ratibor, Oppeln, Brieg, Breslau, Glogau, Frankfort, Custrin and Stettin, with the seaport of Swinemiinde at its mouth. Glogau, Ciistrin and Swinemiinde are strongly fortified.

The earliest important undertaking with a view of improving the 'waterway was due to the initiative of Frederick the Great, who recommended the diversion of the river into a new and straight channel in the swampy tract of land known as the Oderbruch, near Ciistrin. The work was carried out in the years 174 6 - 1 753, a large tract of marshland being brought under cultivation, a considerable detour cut off, and the main stream successfully confined to the canal, 12 M. in length, which is known as the New Oder. The river at present begins to be navigable for barges at Ratibor, where it is about loo ft. wide, and for larger vessels at Breslau, and great exertions are made by the government to deepen and keep open the channel, which still shows a strong tendency to choke itself with sand in certain places. 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. These engineering works were completed in 1896. (2) In1887-1891the Oder-Spree canal was made to connect the two rivers named. The canal leaves the Oder at Fiirstenberg (132 m. above its mouth) at an altitude of 93 ft., and after 15 m. enters the Friedrich-Wilhelm canal (134 ft.). After coinciding with this for 7 m., it makes another cut of 5 m. to the Spree at Fiirstenwalde (126 ft.). Then it follows the Spree for 12 m., and at Gross Tranke (121 ft.) passes out and goes. to Lake Seddin (106 ft.), 15 m. (3) The deepening and regulation of the mouth and lower course of the stream, consisting of the Kaiserfahrt, 3 m. long, affording a waterway between the Stettiner Haff and the river Swine for the largest ocean-going vessels; a new cut, 44 m. long, from Vietzig on the Stettiner Haff to Wollin Island; the Parnitz-Dunzig and Dunzig-Oder canals, together i m. long, constituting the immediate approach to Stettin. Vessels drawing 24 ft. are now able to go right up to Stettin. In 1905 a project was sanctioned for improving the communication between Berlin and Stettin by widening and deepening the lower course of the river and then connecting this by a canal with Berlin. Another project, born at the same time, is one for the canalization of the upper course of the Oder. About 4,000,000 tons of merchandize pass through Breslau (up and down) on the Oder in the year.

See Der Oderstrom, sein Stromgebiet and seine wichtigsten Nebenflusse; hydrographische, wasserwirtschaftliche and wasserrechtliche Darstellung (Berlin, 1896).