III Climate

II Major Rivers and Lakes

The United States has an extensive inland waterway system, much of which has been improved for navigation and flood control and developed to produce hydroelectricity and irrigation water. Some of the world's larger dams, man-made lakes, and hydroelectric power plants are on U.S. rivers. The Mississippi-Missouri river system (c.3,890 mi/6,300 km long), is the longest in the United States and the second longest in the world. With its hundreds of tributaries, chief among which are the Red River, the Ohio, and the Arkansas, the Mississippi basin drains more than half of the nation. The Yukon (Юкон), Columbia, Colorado, and Rio Grande also have huge drainage basins. Other notable river systems include the Connecticut, Hudson, Delaware, Potomac, James, Alabama, Trinity, and Sacramento.

The Great Salt Lake and Alaska's Iliamna are the largest U.S. lakes outside the Great Lakes and Lake of the Woods, which are shared with Canada (Lake Michigan and Iliamna are the largest freshwater lakes entirely within the United States). The Illinois Waterway connects the Great Lakes with the Mississippi River, and the New York State Canal System links them with the Hudson. The Intracoastal Waterway provides sheltered passage for shallow draft vessels along the Atlantic and Gulf Coasts.

The Great Lakes: the largest of them is Lake Superior (Верхнее) (183 m above sea level), Lake Michigan, Lake Huron (Гурон), Lake Erie (Эри) from which the Niagara River rushes over the Niagara Falls into Lake Ontario, out of which flows the St. Lawrence River.

All the lakes are connected by canals or navigable channels and take a very important place in the economic life of the USA and Canada.

The United States has a broad range of climates, varying from the tropical rain-forest of Hawaii and the tropical savanna of S Florida to the subarctic and tundra climates of Alaska. East of the 100th meridian (the general dividing line between the dry and humid climates) are the humid subtropical climate of SE United States and the humid continental climate of NE United States. Extensive forests are found in both these regions. West of the 100th meridian are the steppe climate and the grasslands of the Great Plains; trees are found along the water courses.

In the SW United States are the deserts with the hottest and driest spots in the United States. Along the Pacific coast are the Mediterranean-type climate of S California and, extending north into SE Alaska, the marine West Coast climate. The Pacific Northwest is one of the wettest parts of the United States and is densely forested. The Rocky Mts., Cascades, and Sierra Nevada have typical highland climates and are also heavily forested. In addition to the Grand Canyon in Arizona and Great Salt Lake in Utah, widely publicized geographic marvels of the United States include Niagara Falls, on the New York-Canada border; the pink cliffs of Bryce Canyon National Park, in Utah; and the geysers of Yellowstone National Park, primarily in Wyoming.

Дата добавления: 2014-01-04