Work of River

  • Rivers are very important for humankind. People have settled on the banks of rivers since the earliest times. It is due to the availability of water for drinking, bathing, cooking and cultivation of crops.
  • Different types of landforms are formed as a result of work of river. Landforms shaped by running water are known as fluvial landforms. Mainly two types of landforms are formed erosional landforms, and depositional landforms.
  • Erosional landforms formed by the fluvial agents are valleys, ravine canyon, spur, col, etc.
  • Depositional landforms formed by the fluvial processes are alluvial fan, flood plain, braided river, and oxbow lake.
  • There are three courses of river: the upper course, the middle course, and the lower course.
  • In upper course, river usually flows through mountainous region. Erosion is the dominant work of river in this course.
  • The landforms formed during the upper course of the river are gorge or I-shaped valley, V-shaped valley, interlocking spurs, pot holes, waterfall, rapids and cataract.
  • River enters the plains in middle course. Speed of river slows down because of the decreased gradient. Main work of river in this course is transportation of sediments.
  • The landforms formed by the rivers in the middle course are alluvial fan, flood plain, meanders, ox-bow lake and braided river.
  • River flows considerably slow in the lower course. Main work of river in this course is deposition of sediments.
  • The landforms formed by a river in the lower course are delta, distributaries, estuary and levee.
  • The way river branches on the landscape are called drainage pattern. Shape of the pattern depends on rocks, soil, climate, etc.
  • Three basic drainage patterns are dendritic pattern, trellis pattern, and radial pattern.
  • Dendritic pattern is a treelike branching pattern.
  • Trellis pattern is a rectangular drainage pattern.
  • Radial pattern is a spoke like pattern of rivers.
  • River valley passes through different stages of its life-cycle. The major stages of river valley development are youthful stage, mature stage, and old stage.
  • Rivers begin their work of erosion in youthful stage.
  • In the mature stage, the gradient lessens and river valley becomes wider.
  • The river valley becomes broad and shallow in the old stage.
  • Extensive use of rivers has led to its pollution. The river pollution damages plants, animals, and the natural biological communities. Necessary steps need to be taken to keep our rivers clean.

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