1. What is drainage?

     The flow of water through well-defined channels is known as drainage and the network of such channels is called a drainage system. The drainage pattern of an area is the outcome of the geological time period, nature and structure of rocks, topography, slope, amount of water flowing and the periodicity of the flow.

2. What is dendritic and radial? Give example?

    The drainage pattern resembling the branches of a tree is dendritic. The example of which are the rivers of northern plain.
    When the rivers originate from a hill and flow in all directions, the drainage pattern is known as radial. The rivers originating from the Amarkantak range present a good example of it.

3. What is trellis and centripetal?

    When the primary tributaries of rivers flow parallel to each other secondary tributaries join them at right angles, the pattern is known as trellis.
When the rivers discharge their waters from all directions in a lake or depression the pattern is known as centripetal.

4. What is catchment area and drainage basin?

    A river drains the water collected from a specified area, which is called its catchment are . An area drained by a river and its tributaries is called a drainage basin.

5. What is watershed?

    The boundary line separating one drainage basin from the other is known as the watershed. While those of small rivulets and rills are often referred to as watersheds. Watersheds are small in area. It is marked by unity. One part of the water shed directly affects the other parts and the unit as a whole.

6. What is river basin?

    The catchments of large rivers are called river basin. River basins cover large areas. It is marked by unity. One part of the river basin directly affects the other parts and the unit as a whole.

7. Difference between watershed and river basin?

8. What are the bases of Indian drainage system? On the basis of discharge of water?

    On the basis of discharge of water, it may be grouped into (i) the Arabian sea drainage and (ii) the Bay of Bengal drainage. They are separated from each other through the Delhi ridge, the Aravalis and the sabyadris. Nearly 77 percent of the drainage area consisting of the Ganga, the Bdrahmaputra, the Mahanadhi, the Krishna, etc is oriented towards the Bay of Bengal while 23 percent comprisig the Indus, the Narmata, the Tapi, the Kahi and the Periyar systems discharge their waters in the Arabian Sea.

9. What are the categories of the size of the watershed, the drainage basins of India?

   On the basis of the size of the watershed the drainage basins of India are grouped into three categories. (i) Major river basins with more than 20,000 sq.km of catchment areas. It includes 14 drainage basins such as the Ganga, the Brahmaputra, the Krishna, the Tapi, the Narmada, the Mahi, the pennar, the Sabarmati the Barak etc. (ii) Medium river basins with catchment area between 2,000- 10,000 sq1.km incorporating 44 river basins such as the Kalindi, the periyar the maghna, etc. (iii) Minor river basins with catchment area of less than 2,000 sq. km include fairly good number of rivers flowing in the area of low rainfall.

10. What are the classification of Indian drainage System?

     On the basis of the mode of origin, nature and characteristic, the Indian drainage may also be classified into the Himalayan drainage and the peninsular drainage. Although it has the problems of including the chambal, the Betwa.