Average height of Kosi Plain from mean sea level is
30 m
The Kosi plain lies about 30 metres above mean sea level — option 2.
Why so low. The Kosi plain forms part of the north Bihar section of the Middle Ganga Plain, a vast expanse of recent alluvium laid down by rivers descending from the Himalaya. The whole of the Bihar plain lies between roughly 30 and 60 metres above sea level, and its slope is extraordinarily gentle — of the order of 15 to 20 centimetres per kilometre from north-west to south-east.
| Feature | Consequence of the low, flat surface |
|---|---|
| Very slight gradient | Rivers lose the power to carry silt and drop it on the bed, which then rises above the surrounding land |
| Shifting channels | The Kosi has moved about 120 km westward in two centuries |
| Poor drainage | Extensive waterlogged tracts and ox-bow lakes, locally called chaur and maun |
| Flooding | About three-quarters of north Bihar is flood-prone — the most of any Indian state |
A useful cross-check on the figure. Patna, on the Ganga in the middle of the plain, stands at about 53 metres. The Kosi plain lies to the north-east and downstream of it, so a figure of about 30 metres is exactly what one would expect, while 150 or 300 metres would put the plain at the height of a plateau. That kind of internal consistency check is the safest way to handle a numerical geography question.
What the plain is made of. Newer alluvium, called khadar, in the flood plains, renewed by silt every year and very fertile; and older alluvium, bhangar, on the slightly higher ground away from the rivers. North of the plain, along the Nepal border, lies the Terai, a damp, marshy, formerly forested belt.
Hence, the answer is 30 m.
Similar Questions
Which of the following drainage systems drains the lands of Bihar ?
Munger Hilly region is a part of which of the following physiographic region ?
Which river is known as the ‘Sorrow of Bihar’ ?
Important Questions from Geography
- Through which Indian state does the Tropic of Cancer pass?
- Who created the first map of India?
- What type of forest is the Sundarbans?
Which of the following drainage systems drains the lands of Bihar ?
Munger Hilly region is a part of which of the following physiographic region ?
