India’s drainage system refers to the network of rivers and streams that drain the Indian subcontinent. These rivers are vital for agriculture, human settlement, and ecological balance. The system is shaped by India’s diverse topography, climate, and geology. It can be broadly classified into major river systems and their respective watersheds, which define how water flows across regions into seas or oceans.
Table of Contents
Classification of Drainage Systems
India’s drainage system is classified on the basis of the outlet of the rivers and their flow direction:
1. Himalayan Drainage System
This system includes rivers that originate from the Himalayas and are perennial in nature, meaning they are fed by both rainfall and snowmelt.
- Major Rivers: Indus, Ganga, Yamuna, Brahmaputra
- Characteristics:
- Large catchment areas
- Meandering rivers
- Formation of fertile alluvial plains
- Well-developed tributary systems
2. Peninsular Drainage System
These rivers originate from the Western Ghats or central highlands and are mostly rain-fed.
- Major Rivers: Godavari, Krishna, Mahanadi, Narmada, Tapi, Kaveri
- Characteristics:
- Older, mature rivers with shorter courses
- Flow through hard rocks and well-defined valleys
- Seasonal variations in water volume
Important River Systems and Their Watersheds
1. Indus River System
- Origin: Tibet (China), near Lake Mansarovar
- Enters India in Ladakh, flows through Punjab and into Pakistan
- Major tributaries in India: Jhelum, Chenab, Ravi, Beas, Sutlej
- Drainage basin: Covers Jammu & Kashmir, Himachal Pradesh, Punjab, Haryana
2. Ganga River System
- Origin: Gangotri Glacier (Uttarakhand)
- Main tributaries: Yamuna, Ghaghara, Gandak, Kosi, Son
- Empties into the Bay of Bengal
- Drainage basin: Covers Uttar Pradesh, Bihar, West Bengal, and parts of Madhya Pradesh, Jharkhand
3. Brahmaputra River System
- Origin: Angsi Glacier (Tibet) where it is called Tsangpo
- Enters India in Arunachal Pradesh as Dihang
- Joins the Ganga in Bangladesh to form the Meghna delta
- Drainage basin: Assam, Arunachal Pradesh, and parts of Northeast India
4. Godavari River System
- Origin: Nashik (Maharashtra)
- Also called the “Dakshin Ganga”
- Flows eastward into the Bay of Bengal
- Drainage basin: Maharashtra, Telangana, Andhra Pradesh, Chhattisgarh
5. Krishna River System
- Origin: Western Ghats (Maharashtra)
- Important tributaries: Bhima, Tungabhadra
- Drainage basin: Maharashtra, Karnataka, Telangana, Andhra Pradesh
6. Narmada and Tapi Rivers
- Flow westward into the Arabian Sea
- Originate in Madhya Pradesh (Narmada) and Maharashtra (Tapi)
- Flow through rift valleys formed by tectonic activity
Watersheds in India
A watershed is a geographic area from which all water drains into a common outlet, such as a river or lake. Watersheds are crucial for managing water resources, preventing floods, and supporting biodiversity.
Major Watersheds of India:
- Himalayan Watershed
- Includes Indus, Ganga, and Brahmaputra river basins
- Covers Northern India and the Indo-Gangetic plains
- Central Highlands Watershed
- Covers rivers like Narmada, Tapi, Mahi
- Flow into the Arabian Sea
- Eastern Ghats Watershed
- Rivers like Godavari, Krishna, Mahanadi drain eastward into the Bay of Bengal
- Western Ghats Watershed
- Small west-flowing rivers like Mandovi, Sharavathi, Periyar
- Short but steep rivers due to escarpment terrain
- Desert and Inland Watershed
- Includes ephemeral rivers like Luni in Rajasthan
- No major outlet, often drains into inland basins or evaporates
Drainage Patterns in India
- Dendritic Pattern – Tree-like pattern, e.g., Ganga system
- Radial Pattern – Flow outward from a central high point, e.g., Amarkantak
- Trellis Pattern – Tributaries meet main river at right angles
- Rectangular Pattern – Faulted terrain causing angular turns in river flow
Conclusion
India’s drainage system and watersheds form the backbone of the country’s agriculture, ecosystem, and human habitation. A proper understanding and management of these systems is vital for sustainable development, especially in the face of increasing water scarcity, climate change, and urbanization. Watershed management programs have become essential for conserving water, preventing soil erosion, and improving livelihoods in both rural and urban India.