Lakes and Rivers

Lakes and rivers are both bodies of water. Dictionary.com defines a lake as 'a body of fresh or salt water of considerable size, surrounded by land. 'A river is defined as 'a natural stream of water of fairly large size flowing in a definite course or channel or series of diverging and converging channels.'

The differences between lakes and rivers come in movement, size, and shape. A lake is a still body of water. A lake differs from a river in the movement of the water. Rivers usually are moving or flowing in one direction along a bank on either side. A lake does not move except maybe due to the wind.

Secondly, a lake is surrounded on all sides by land. It is an inland body of water and is bigger than a pond. There is actually no specific rule for a still body of water to be considered a lake rather than a pond. The general rule is that a lake must be at least two-five acres in size.

In addition, lakes are not connected to seas or oceans in any way. They are inland bodies of water. Rivers usually flow into a sea or ocean at some point. Rivers are usually much longer than lakes. Lakes and rivers are usually composed of fresh water. Lakes may be salt water also. Lake Michigan-Huron is the largest lake in the world. It is in the United States. Lake Baikal in Siberia is the deepest lake in the world. Lake Tanganyika is the longest lake on earth. It is in Africa.

Most lakes are in the Northern Hemisphere. More than one-half are in the Canadian regions. Some lakes have a seepage system where water does leak out. These could be rivers or streams. If a lake has no outlet, the water evaporates due to the heat. Lakes may be located anywhere, such as in mountainous areas, flat areas, and valleys. They may be located underground. Some of today's lakes are man-made for the purpose of creating hydro-electricity, for industrial use, recreational use, water supply or agricultural purposes.

A river is a natural watercourse. Rivers are found in every part of the world. The beginning of a river is called the source. The end of a river is called its mouth. It is where the river flows into a bigger body of water. Rivers are usually bigger than streams, brooks or creeks. There is no specific definition of size as to what separates a river from a stream or brook. A river can be several streams connected together. During a rain, the water collects in some type of basin and then flows off into a river. Melting water from ice or snow would drain the same way.

Movement of water along a river is called a current. A river may be a few miles long or run across a continent. The Nile River in Africa and the Amazon in South America are the longest rivers on earth. Some rivers flow all year. Some dry up in hot weather. Although rivers are not man-made, dams can be built to redirect the water, sometimes to build an artificial lake. Smaller streams or rivers which flow into bigger ones are called tributaries.

Rivers flow from higher to lower elevations from places called divides. Every continent except Antarctica has a continental divide. A continental divide determines the way the area rivers flow and drain. The Continental Divide in the Americas determines which rivers flow to the Atlantic and which to the Pacific Ocean. The divide in North America runs from the Northwest of Canada along the Rocky Mountains, through New Mexico and on down to South America. Rivers on the west side of the divide mainly flow toward the Pacific and those on the east side to the Atlantic. However, rivers east of the Rocky Mountains and north of the Canadian border flow into the Arctic Ocean. Some rivers drain to the Atlantic Ocean via the Gulf of Mexico.