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Information on Rivers
In upland rivers, rapids with whitewater or even waterfalls occur. Rapids are often used for

recreational purposes (see whitewater kayaking). Fast flowing rivers and waterfalls are
harnessed as sources of energy, via watermills and hydroelectric plants.

Rivers have been important historically in determining political boundaries and defending
countries. For example, the Danube was a longstanding border of the Roman Empire, and
today forms most of the border between Bulgaria and Romania. The Mississippi in North
America, and the Rhine in Europe, are major east-west boundaries in those continents. The

Orange and Limpopo Rivers in Southern Africa form the boundaries between various
provinces and countries along their routes.

Flooding

Flooding is a natural part of a river's cycles. The majority of the erosion of river channels

and the erosion and deposition on the associated floodplains occur during flood stage.
Human activity, however, has upset the natural way flooding occurs by walling off rivers,
straightening their courses and by draining of natural
wetlands.

Flooding can be mitigated.

Direction of flow

A misconception, particularly amongst school children in the

United States, [2][3] is that most, or even all, rivers flow from
north to south. Rivers in fact flow down gradient irrespective
of direction, often in a complex meandering path involving all
directions of the compass. [4][5][6]

Indeed, few major rivers in the continental US flow north, as
most of the country is located in the watershed of the Pacific

or Atlantic oceans or the Gulf of Mexico, with very few rivers
flowing northward toward the Arctic Ocean, Great Lakes, or Hudson Bay. However, thousands
of north-flowing rivers exist elsewhere, including such major watercourses as the Nile,
Mackenzie, Rhine, Yenisei, Nelson, Lena, etc. Four of the ten longest river systems of the

world flow mainly north.

Management

Rivers are often managed or controlled to make them more useful and less disruptive to
human activity.

(God's Amazing Landscapes) 17