Our Revision Notes for GSEB Class 9 Social Science Notes Chapter 15 Drainage System summarises the key points of a chapter and useful resource to prepare effectively for the upcoming board exams.

Drainage System Class 9 GSEB Notes Social Science Chapter 15

Drainage System Class 9 GSEB Notes

→ Drainage system of India: Drainage system of India is divided into two parts:

• Himalayan Rivers
• Peninsular Rivers.

→ 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.

→ Two major rivers of Himalaya, Sindhu and Brahmaputra, originate in the northern part of this mountain system.

→ Peninsular rivers are seasonal because these are dependent on rain water.

→ During dry season, their flow is either reduced or is totally stopped.

Himalayan Rivers:

• Sindhu, Ganga and Brahmaputra are major rivers originating in the Himalayas.
• River Sindhu emerges from near Mansarovar in Tibet. Ravi and Jhelum are her main tributaries.
• Many Himalayan rivers meet Ganga. Among them Ghaghra, Gandak and Kosi are major.
• Yamuna emerges from Yamnotri in Himalayas.
• Few rivers like Chambal, Betwa originate in peninsular plateau and meet Yamuna.
• The combined flow of the rivers from north and south is dividee ahead into two branches. One branch enters Bangladesh and is known there as Padma. Another branch is known as Bhagirathi. Hugh in west Bengal, Finally, these two branches meet the Bay of Bengal.
• Brahmaputra originates near Mansarovar in Tibet.
• This river flows in the east parallel to Himalayan Mountain System.
• This river, with Lohit and Kenula tributaries is collectively known as Brahmaputra in Assam.

Peninsular Rivers:
→ Western Ghats is considered to be the main water divide for peninsular rivers.

→Large rivers like Narmada and Tapi flow from east to west and meet the Arabian Sea in the west.

→ Narmada originates near Amarkantak plateau in Madhya Pradesh.

→ Tributaries of this river do not have longer flow. Its basin area is spread over Madhya Pradesh and Gujarat.

→ Satpuda ranges are located in Madhya Pradesh, Tapi river originates in Betul District.

→ It flows in a rift valley, parallel to Narmada, and meets Arabian Sea.

→ Godavari is the largest of the peninsular rivers. It starts from the slopes of Western Ghats near
Nasik in Maharashtra. It is about 1465 km long. It flows to the east and meets Bay of Bengal.

→ Major tributaries are Puma, Vardha, Pranhita, Pranhita, Manjara, Vainganga and Penganga.

→ Mahanadi originates in the mountainous area of Chhattisgarh. It flows through Odisha and meets Bay of Bengal. It is about 860 km long and has basin spread in chhattisgarh, Jharkhand and Odisha.

→River Krishna originates near Mahabaleshwar in Maharashtra. It is about 1400 km long. Tungbhadra, Koyna, Ghatprabha, Musi and Bhima are her major tributaries.

→ Its basin extends in Maharashtra, Karnataka and Andhra Pradesh.

→ River Kaveri has its origin in the Brahmagiri Range in Western Ghats and is about 760 km long. Amravati, Bhavani, Hemvati and Kalini are her major tributaries.

Lakes :

• Fresh water lakes are found more in the Himalayan region.
• In Kashmir, glacial lakes are formed.
• Sea tides have created ‘lagoon’ lakes. Chilka, Koleru and Pulicat are examples of this type of lakes.
• Sambhar lake in Rajasthan is a saline lake and salt is produced from it.
• Wular Lake in Kashmir has a tectonic origin.
• Other fresh water lakes of this area are Dal, Bhimtal, Loktal and Badapani.
• Lakes are useful to man in many ways.
• The accumulated water can be utilised 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.

Economic importance of rivers :

• Rivers are the natural resource of water.
• Agriculture and industries have developed due to rivers. Ancient civilizations also flourished
  along rivers.
• Major cities have developed along the river blanks, e.g. Delhi, Kolkata, Ahmedabad, Bharuch, Surat etc.

River – pollution :

• Water pollution increases due to industrialization and urbanization. Pollution of river water has become our a national problem. Government is putting in special efforts to prevent river pollution.
• Strict rules should be formed to prevent industrial units from releasing industrial effluents in the rivers.