Drainage

Q65. Which river is known as ‘Dakshin Ganga’? Describe its main features.
Or
Why is river Godavari known as ‘Dakshin Ganga’?

Ans. Features of Godavari river

                         i.        The Godavari is the largest Peninsular river. It rises from the slopes of the Western Ghats in the Nasik district of Maharashtra. Its length is about 1500 km.

                        ii.        It drains into the Bay of Bengal. Its drainage basin is also the largest among the peninsular rivers. The basin covers parts of Maharashtra, Madhya Pradesh, Odisha and Andhra Pradesh.

                       iii.        The Godavari is joined by a number of tributaries such as the Purna, the Wardha, the Pranhita, the Manjra, the Wainganga and the Penganga. The last three tributaries are very large. Because of its length and the area it covers, it is also known as the ‘Dakshin Ganga’.

 
Q66. State some economic benefits of rivers and lakes.

Ans. Rivers

Using rivers for irrigation, navigation, hydro-power generation is of special significance – particularly to a country like India, where agriculture is the major source of livelihood of the majority of its population.

Lakes

                         i.        Lakes are attraction for tourists.

                        ii.        The Sambhar Lake in Rajasthan is a salt water lake. Its water is used for producing salt.

                       iii.        A lake helps to regulate the flow of a river. During heavy rainfall, it prevents flooding and during the dry season, it helps to maintain an even flow of water.

                       iv.        Lakes can also be used for developing hydel power.

Q67. Below are given names of a few lakes of India. Group them under two categories – natural and created by human beings.

Ans.

Q68. Differentiate between Ganga and Godavari river system.

Ans. Difference between Ganga and Godavari river system

Q69. What are the different types of drainage patterns?

Ans. These are dendritic, trellis, rectangular, and radial patterns.

Dendritic pattern - The dendritic pattern develops where the river channel follows the slope of the terrain. The stream with its tributaries resembles the branches of a tree, thus the name dendritic.

Trellis pattern - A river joined by its tributaries, at approximately right angles, develops a trellis pattern. A trellis drainage pattern develops where hard and soft rocks exist parallel to each other.

Rectangular pattern - A rectangular drainage pattern develops on a strongly jointed rocky terrain.

Radial pattern - The radial pattern develops when streams flow in different directions from a central peak or dome like structure.

 
Q70. Write a note on the Ganga River System.

Ans. The headwaters of the Ganga, called the ‘Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand. At Haridwar the Ganga emerges from the mountains on to the plains. The Ganga is joined by many tributaries from the Himalayas, a few of them being major rivers such as the Yamuna, the Ghaghara, the Gandak and the Kosi. The river Yamuna rises from the Yamunotri Glacier in the Himalayas. It flows parallel to the Ganga and as a right bank tributary, meets the Ganga at Allahabad. The Ghaghara, the Gandak and the Kosi rise in the Nepal Himalaya. They are the rivers, which flood parts of the northern plains every year, causing widespread damage to life and property but enriching the soil for the extensive agricultural lands. The main tributaries, which come from the peninsular uplands, are the Chambal, the Betwa and the Son. The length of the Ganga is over 2500 km.