CBSE Class 9 Geography Notes Chapter 3 Drainage

Drainage Class 9 Notes are based on CBSE Class 9 Geography Chapter 3. It explains how rivers, streams, and lakes form a drainage system in India. Drainage refers to the network of rivers and streams that drain water from land into seas, lakes, or oceans.

The chapter is included in CBSE Class 9 syllabus, focuses on Himalayan rivers, Peninsular rivers, drainage patterns, river basins, and lakes. These Class 9th Geography Chapter 3 Notes are important for understanding India’s water resources, agriculture, and settlement patterns. Studying Class 9 Drainage Notes also helps students answer map-based and descriptive questions confidently in exams.

What is Drainage?

Drainage refers to the river system of an area. A drainage basin is the region drained by a single river system.

An elevated area, like a mountain, separates two drainage basins, forming a water divide. Understanding India's drainage systems is important for studying its physical geography. This chapter provides essential Class 9 Geography Chapter 3 Notes.

Drainage Class 9 Notes

These notes cover the entire NCERT Class 9 Geography Syllabus Chapter 3. It includes the types of drainage systems, rivers, lakes, and role of rivers in the economy. 

Drainage Systems in India

Indian rivers divide into two main groups: Himalayan and Peninsular rivers. They differ in origin, flow, and characteristics.

The Himalayan Rivers

These rivers are long and have many tributaries. Together, a river and its tributaries form a river system.

• The Indus River System: The Indus rises near Lake Mansarovar in Tibet. It enters India in Ladakh. Its tributaries include the Satluj, Beas, Ravi, Chenab, and Jhelum. The river is one of the world's longest.

• The Ganga River System: The Bhagirathi, fed by the Gangotri Glacier, is the Ganga's source. It joins the Alaknanda at Devaprayag. Major Himalayan tributaries include the Yamuna, Ghaghara, Gandak, and Kosi. The Ganga divides at Farakka, forming the Bhagirathi-Hooghly and a mainstream that joins the Brahmaputra in Bangladesh to form the Meghna. This creates the Sundarban Delta.

• The Brahmaputra River System: The Brahmaputra originates east of Mansarovar Lake. It takes a 'U-turn' at Namcha Barwa and enters India as the Dihang. It merges with Dibang and Lohit to become the Brahmaputra in Assam.

The Peninsular Rivers

The Western Ghats act as the main water divide in Peninsular India. Most rivers flow east into the Bay of Bengal, forming deltas. Some flow west, forming estuaries.

• The Narmada Basin: Rises in Amarkantak hills. Flows west through gorges (e.g., Marble Rocks) and forms Dhuadhar Falls. Its basin covers Madhya Pradesh and Gujarat.

• The Tapi Basin: Rises in the Satpura ranges. Its basin covers parts of Madhya Pradesh, Gujarat, and Maharashtra. It is a west-flowing river.

• The Godavari Basin: The largest Peninsular river, also called 'Dakshin Ganga'. It rises in the Western Ghats of Maharashtra. Its basin covers parts of Maharashtra, Madhya Pradesh, Odisha, and Andhra Pradesh. Its length is about 1500 km.

• The Mahanadi Basin: Rises in Chhattisgarh's highlands. Its basin extends across Maharashtra, Chhattisgarh, Jharkhand, and Odisha. Its length is about 860 km.

• The Krishna Basin: Originates near Mahabaleshwar. Its basin includes Maharashtra, Karnataka, and Andhra Pradesh. Its length is about 1400 km.

• The Kaveri Basin: Rises in the Brahmagiri range of the Western Ghats. Its basin covers Karnataka, Kerala, and Tamil Nadu. Its length is about 760 km.

Lakes

India has various lakes differing in size and type.

• Formation: Some are permanent, some seasonal. Glaciers, wind, river action, and human activities form them.
  Types:

• Ox-bow lakes: Formed by meandering rivers on floodplains.

• Lagoons: Formed by spits and bars in coastal areas (e.g., Chilika Lake).

• Saltwater lakes: Found in regions of inland drainage, often seasonal (e.g., Sambhar Lake).

• Freshwater lakes: Mostly in the Himalayas, often of glacial origin (e.g., Wular Lake - tectonic origin, Dal Lake, Bhimtal).

• Importance: Regulate river flow, prevent floods, maintain even water flow in dry seasons, generate hydel power, moderate climate, support aquatic ecosystems, enhance beauty, and provide recreation.

Role of Rivers in the Economy

Rivers are fundamental natural resources. They provide water for irrigation, navigation, and hydropower generation. They support human activities and economies.

River Pollution

Rising domestic, municipal, industrial, and agricultural demands affect river water quality. Untreated sewage and industrial effluents pollute rivers. Action plans are launched to clean rivers.