Читать книгу The Circle of Knowledge: A Classified, Simplified, Visualized Book of Answers - Various - Страница 106
FORMATION, CHARACTERISTICS AND
PECULIARITIES OF RIVERS
ОглавлениеRivers have their sources from springs or from the melting of accumulations of snow. They do not, however, receive their largest supplies from the actual summits of mountains, for copious springs are rarely met with in such situations, nor are glaciers formed on the highest points of mountains, but more usually on slopes of the upper mountain valleys. It is, accordingly, in the latter localities that many of the largest rivers take their rise.
Watershed. It not unfrequently happens that several rivers take their rise in one mountain ridge, some flowing in one direction, and others taking an opposite course. Such a ridge is termed a watershed. Thus the Rhine, the Rhone, and the Danube all take their rise in the Alps, the first discharging itself into the North Sea, the second into the Mediterranean Sea, and the last into the Black Sea.
Basin. The portion of country drained by a river and its tributary streams is called its basin, from its catching the rains which fall within its circuit, and which the river carries to the sea. The largest river-basin in Europe is that of the Volga, in Asia, that of the Ganges, in Africa that of the Nile, in North America that of the Mississippi, and in South America that of the Amazon.
THE GREAT RIVERS OF THE WORLD
| RIVER | Length in Miles | Emptying Into | Area of Drainage in Square Miles, etc. |
|---|---|---|---|
| Mississippi-Missouri (United States) | 4,330 | Gulf of Mexico | 1,245,000 |
| Nile (Egypt) | 3,500 | Mediterranean | 1,050,000 |
| Amazon (Brazil): the only large river with direct latitudinal course | 3,300 | At Ocean on the Equator | 2,700,000 |
| Yangtze-Kiang (China) | 3,000 | Yellow Sea | 548,000 |
| Congo (Central Africa) | 2,900 | Atlantic Ocean | 1,430,000 |
| Lena (Russia in Asia) | 2,800 | Arctic Ocean | 856,000 |
| Amur (Russia in Asia) | 2,800 | Gulf of Saghalin | 772,000 |
| Mekong (Indo-China)[71] | 2,800 | China Sea | Nav. 200 miles |
| Yenisei (Russia in Asia) | 2,700 | Bay of Yenisei | 1,000,000 |
| Niger (West Africa) | 2,600 | Atlantic Ocean | 808,000 |
| Hoangho (China) | 2,500 | Gulf of Pe-Chi-Li | 376,400 |
| Obi (Russia in Asia) | 2,300 | Gulf of Obi | 1,125,000 |
| Plata-Parana (Argentina and Brazil) | 2,300 | Atlantic Ocean | 2,300,000 |
| Mackenzie (Canada) | 2,300 | Arctic Ocean | 676,000 |
| Volga (Russia in Europe) | 2,200 | Caspian Sea | 560,000 |
| St. Lawrence (United States and Canada) | 2,200 | Gulf of St. Lawrence | 500,000 |
| Yukon (Alaska) | 2,200 | Behring Sea | 500,000 |
| Indus (India) | 2,000 | Arabian Sea | 373,000 |
| Sao Francisco (Brazil) | 1,800 | Atlantic Ocean | 249,000 |
| Sir Daria (Turkestan) | 1,800 | Sea of Aral | 175,000 |
| Brahmaputra or Burrampooter (India) | 1,800 | Bay of Bengal | Nav. 800 miles |
| Rio Grande del Norte (U. S. and Mexico) | 1,800 | Gulf of Mexico | 240,000 |
| Danube (Austria-Hungary) | 1,780 | Black Sea | 311,000 |
| Saskatchewan-Nelson (Canada) | 1,732 | Hudson Bay | 730,000 |
| Euphrates (Turkey in Asia) | 1,700 | Persian Gulf | 260,000 |
| Zambesi (East Africa) | 1,600 | Indian Ocean | 800,000 |
| Ural (Russia in Europe) | 1,500 | Caspian Sea | 85,000 |
| Arkansas (United States) | 1,500 | Mississippi River | 181,000 |
| Orinoco (Colombia and Venezuela) | 1,500 | Atlantic Ocean | 364,000 |
| Ganges (India) | 1,500 | Bay of Bengal | 409,000 |
| Amu (Turkestan) | 1,400 | Sea of Aral | 174,000 |
| Columbia (United States) | 1,400 | Pacific Ocean | 260,000 |
| Dnieper (Russia in Europe) | 1,400 | Black Sea | 203,000 |
| Murray (Australia) | 1,400 | Indian Ocean | 351,000 |
| Don (Russia in Europe) | 1,300 | Sea of Azov | 166,000 |
| Orange (S. W. Africa) | 1,200 | Atlantic Ocean | 370,000 |
| Irawaddy (East India) | 1,200 | Indian Ocean | Nav. 800 miles |
| Colorado (United States) | 1,100 | Gulf of California | 250,000 |
| Senegal (West Africa) | 1,100 | Atlantic Ocean | 270,000 |
| Tigris (Turkey in Asia) | 1,000 | Euphrates and Persian Gulf | Nav. generally for small boats |
| Ohio (United States) | 970 | Mississippi River | 201,000 |
| Churchill (Canada) | 900 | Hudson Bay | Nav. by canoes |
| Magdalena (Colombia) | 840 | Caribbean Sea | Nav. 600 miles |
| Rhine (Germany) | 800 | North Sea | 76,000 |
| Cambia (West Africa) | 750 | Atlantic Ocean | Nav. 300 miles |
| Elbe (Germany) | 720 | North Sea | 57,000 |
| Fraser (British Columbia) | 650 | Gulf of Georgia | Nav. generally for small boats |
| Vistula (Germany, Poland) | 600 | Baltic Sea | 120,000 |
| Sacramento (United States) | 600 | Pacific Ocean | Nav. 300 miles |
| Tagus (Portugal) | 570 | Atlantic Ocean | 32,000 |
| Paranahiba (Brazil) | 530 | Atlantic Ocean | Nav. 400 miles |
| Guadiana (Spain) | 510 | Mediterranean Sea | 32,000 |
| Rhone (France) | 500 | Gulf of Lyons | 38,000 |
| Seine (France) | 480 | English Channel | 30,000 |
| Ebro (Spain) | 470 | Mediterranean Sea | 32,000 |
| Susquehanna (United States) | 450 | Chesapeake Bay | Not navigable |
| Potomac (United States) | 450 | Chesapeake Bay | Nav. to Washington, D. C. |
| Oder (Germany) | 440 | Baltic Sea | 43,000 |
| Po (Italy) | 420 | Adriatic Sea | 29,000 |
| Garonne (France) | 380 | Bay of Biscay | 33,000 |
| Hudson (United States) | 350 | New York Bay | Nav. to Troy; 150 miles |
| Loire (France) | 200 | Bay of Biscay | 25,000 |
| Thames (England) | 200 | North Sea | 5,250 |
Deltas and Estuaries. Owing to local peculiarities at the mouths of rivers, accumulations of sedimentary matter take place in the middle of the stream, dividing it into two or more branches. By these depositions deltas (so called from the Greek letter (Δ) delta) are formed—many of them, as those of the Mississippi and Orinoco and of the Rhine and the Ganges, being of great extent. Some rivers fall into the ocean through estuaries or wide channels, and are subject to a great swell or sudden rise of the waters when the tide enters.
PICTURE DIAGRAM GIVING A COMPARATIVE VIEW OF THE WORLD’S FAMOUS RIVERS AND MOUNTAINS
