GCERT Class 9 Social Science Chapter 15 Solution
Brief Information: This post contains the solution for Chapter 15 Drainage System of Class 9 Social Science (SS) of the Gujarat Board (GSEB) books GCERT.
Q.1 Write short answers for the following questions
(1) Give difference : Himalayan rivers — Peninsular rivers
1) Himalayan rivers contain water throughout the year. These rivers are perennial because of the increase in water volume due to heavy rain during monsoon and due to the melting of snow during summer.
1) Peninsular rivers are seasonal because these are dependent on rain water.
2) They are very long.
2) Their length is less and are also shallow compared to Himalayan rivers.
3) These rivers have cut deep gorges by cutting the mountains.
3) Such features are not found.
4) Meanders are seen.
4) They travel in straight direction.
5) Near its mouth, a river is divided into many tributaries. This divided area turns into a very fertile plain in a triangle shape. This is called Delta.
5) Near mouth they either form estuaries or delta.
(2) Explain : Drainage Pattern and Water Divide
Ans. The word ‘drainage system’ is used for the systematic pattern of rivers. A river and her tributaries come from different directions and merge into a single river. The water of these rivers is emptied into a water reservoir, sea or a desert. Thus, when a river flows through its system in any area, it is called a ‘river basin’. The pattern in which the main river and its tributariesflow is called Drainage Pattern.
When a mountain or an upland separates the flow of water system from one another, it is called Water-divider.
(3) Explain the utility of lakes
Ans. Lakes are useful to man in many ways. Their utility are as follow:
– Rivers originate from lakes.
– In the regions which have more rain, more water can be accumulated in the lakes. The accumulated water can be utilized for irrigation and other purposes.
– The stored water can also be used during drought.
– Reservoirs and lakes formed due to dam are useful for generating hydel power.
– Lakes enhance the natural beauty, hence such lakes have been developed as tourist spots.
– Lakes are also important for fishery and as tourist resorts.
(4) State the remedies to prevent water pollution.
Ans. Water pollution can be prevented by taking following measures:
– Strict implementation of rules to prevent water pollution.
– Water purification projects must be implemented through National River Conservation Project.
– Strict rules should be formed to prevent industrial units from releasing industrial effluents in the rivers. Industrial units should filter harmful contents from the chemical effluents before releasing them in the river.
– In order to keep the river water clean, every citizen should take care not to mix up the domestic waste into the river.
(5) ‘Godavari is named as Ganga of South’ – Give reasons.
Ans. Godavari is the longest peninsular river. It has the largest basin in South India. Thus, is is named as Ganga of South.
Q.2 Answer the following
(1) Explain the Ganga River System.
Ans. Rivers Bhagirathi and Alaknanda emerging from the Gangotri area in Himalayas, merge with each other near Devprayag (Uttarakhand). Ganga leaves the mountainous terrain and enters plains near Haridwar. Many Himalayan rivers meet Ganga.
– Yamuna emerges from Yamunotri in Himalayas. Flowing to the right side of Ganga, it merges with Ganga near Allahabad.
– The source of Ghaghra, Gandak and Kosi rivers lies in Nepal. The northern plain experiences flood disasters every year due to these riversThere is a heavy loss of life and property in some areas, yet India has been able to attain prosperity in agriculture through the fertile plains formed by these rivers.
– Few rivers like Chambal, Betwa originate in peninsular plateau and meet Yamuna. Son river meets Ganga. These rivers originate in semi – arid area, their a length of flow is shorter and have limited volume of water. The combined flow of the rivers from north and south is divided down stream into two branches.
– One branch enters Bangladesh and is known there as Padma. Another branch is known as Bhagirathi – Hugli in west Bengal. Finally, these two branches meet the Bay of Bengal.
– The flow of Ganga, which is known as Padma in Bangladeshi merges there with Brahmaputra river and their combined flow is called Meghna.
– The Ganga – Brahmaputra delta is the most fertile delta and is known as Sundarvan.
(2) Discuss the Narmada basin.
Ans. Narmada originates near Amarkantak plateau in Madhya Pradesh. It flows westward in a rift valley. It flows through a rocky termin of marbles near Jabalpur, and flows faster due to slope. The Dhuandhar Falls are located here.Tributaries of this river do not have longer flow. Most of the rivers meet at right angles. Its basin area is spread over Madhya Pradesh and Gujarat. Naimada is about 1312 km long.
(3) Describe in detail the Krishna and Kaveri basins.
Ans. Krishna Basin: It originates near Mahabaleshwar in Maharashtra. It is about 1400 km long. Tungabhadra, Koyna, Ghatprabha, Musi and Bhima are her major tributaries. Its basin extends in Maharashtra, Karnataka and Andhra Pradesh.
Kaveri Basin: It has its origin in the Brnhmagiri Range in Western Ghats and is about 760 km long. Amaravati, Bhavani, Hemvati and Kalini are her major tributaries. Its basin extends in Kerala,Karnataka and Tamil Nadu. It meets the Bay of Bengal to the south of Cuddalore in Tamil Nadu.
Q.3 Find out the correct option from the given options
(l) Which lakes are formed due to meandering of rivers ?
Ans. (B) Ox-bow
(2) What is it called when a mountain or an upland separates the water flow of rivers from one another ?
(A) Water formation
(B) Water divide
(C) River system
Ans. (B) Water divide
(3) Which of the following is not a peninsular river ?
Ans. (C) Kosi
(4) Which of the following lakes is used for producing salt ?
Ans. (B) Sambhar
(5) Which are the main tributaries of Ganga ?
(A) Yamuna, Ghaghra, Gandak and Kosi
(B) Yamuna, Chambal, Ghaghra and Kosi
(C) Yamuna, Ghaghra, Sharavati and Kosi
(D) Narmada, Ghaghra, Gandak and Kosi
Ans. (A) Yamuna, Ghaghra, Gandak and Kosi