🌊 Drainage (जल निकासी)
🔹 The term Drainage describes the river system (नदी तंत्र) of an area.
🏞 Drainage Basin (जल निकासी बेसिन)
🔹 The area drained by a single river system is called a Drainage Basin.
🌍 World’s Largest Drainage Basin
🔹 The world’s largest drainage basin is of the Amazon River (अमेज़न नदी).
🇮🇳 India’s Largest Drainage Basin
🔹 The largest drainage basin in India is from the Ganga River (गंगा नदी).
🗻 Water Divide (जल विभाजक)
🔹 Any elevated area (ऊँचा क्षेत्र), such as a mountain (पर्वत) or upland (ऊँचाई वाला भूभाग), that separates two drainage basins is called a Water Divide.
🌀 Drainage Patterns (जल निकासी के प्रकार)
🌳 Dendritic Pattern (डेंड्राइटिक पैटर्न)
🔹 Develops where the river channel follows the slope (ढलान) of the terrain.
🔹 The streams with their tributaries resemble the branches of a tree (पेड़ की शाखाओं).
📐 Trellis Pattern (ट्रेलिस पैटर्न)
🔹 A river joined by its tributaries at right angles (समकोण).
🔹 Found where hard and soft rocks exist parallel to each other.
🧱 Rectangular Pattern (रेक्टैंगुलर पैटर्न)
🔹 Develops in strong rocky terrain (कठोर पथरीला क्षेत्र).
⛰ Radial Pattern (रेडियल पैटर्न)
🔹 Develops when streams flow in different directions from a central peak (केन्द्रीय शिखर) or dome-like structure (गुम्बदाकार संरचना).
💧 Perennial River (स्थायी नदी)
🔹 A river which is filled with water throughout the year.
🌊 River System (नदी तंत्र)
🔹 A river along with its tributaries (सहायक नदियाँ) is called a River System.
🌱 Tributary of a Large River (बड़ी नदी की सहायक नदी)
🔹 A small river (छोटी नदी) which joins a large river is called its tributary.
🔹 Example: Yamuna (यमुना), Kosi (कोसी), Gandak (गंडक) – tributaries of Ganga River (गंगा नदी).
💧 Drainage System (जल निकासी तंत्र)
- The drainage systems of India are mainly controlled by the broad relief features (विशाल भू-आकृतिक संरचनाएं) of the subcontinent.
- Based on origin, Indian rivers are divided into two major groups:
- 🏔 Himalayan Rivers (हिमालयी नदियाँ)
- ⛰ Peninsular Rivers (दक्षिणी प्रायद्वीपीय नदियाँ)
🏔 1. Himalayan Rivers (हिमालयी नदियाँ)
- Perennial (सदानीरा) – Water flows throughout the year from rainfall and melting snow.
- Originate north of the mountain ranges and cut deep gorges (खड्ड) through them.
- Have long courses from source to sea.
- Upper course – Intense erosion (कटाव), transport of silt & sand.
- Middle & lower course – Formation of meanders (घुमावदार मोड़), oxbow lakes (अर्धचंद्राकार झील), floodplains, and large deltas.
🌟 Major Himalayan Rivers
- The Indus (सिंधु)
- The Ganga (गंगा)
- The Brahmaputra (ब्रह्मपुत्र)
🌊 The Indus River System (सिंधु नदी तंत्र)
- Origin – Rises in Tibet (तिब्बत) near Lake Mansarowar (मानसरोवर झील).
- Flows west and enters India in Ladakh (लद्दाख), forming a picturesque gorge (सुंदर खड्ड).
- Passes through Baltistan (बाल्टिस्तान) & Gilgit (गिलगित), emerges at Attock (अटोक).
🌊 Tributaries (उप-नदियाँ)
- Zaskar (जांस्कर)
- Nubra (नुब्रा)
- Shyok (श्योक)
- Hunza (हुंजा)
📏 Length & Destination
- Total Length – 2,900 km (One of the longest rivers in the world 🌍)
- Flows southwards to Arabian Sea (अरब सागर), east of Karachi (कराची).
📝 Quick Revision Points
✅ Drainage System = River network of an area
✅ Himalayan Rivers = Perennial, snow-fed & rain-fed
✅ Indus = Origin in Tibet, longest in India, flows into Arabian Sea
🌊 Drainage Systems of India (भारत की जल निकासी प्रणाली)
🗺️ Overview
India’s drainage system is mainly shaped by the broad relief features (भू-आकृति) of the subcontinent.
Rivers are classified into two major groups:
1️⃣ Himalayan Rivers (हिमालयी नदियाँ)
2️⃣ Peninsular Rivers (प्रायद्वीपीय नदियाँ)
🏔️ Himalayan Rivers (हिमालयी नदियाँ)
- Perennial (साल भर बहने वाली) – water from both rain & melted snow.
- Originate north of the mountain ranges (पर्वत श्रृंखला).
- Cut deep gorges (घाटियाँ) through the mountains.
- Long courses, from source to sea.
- Upper course → erosion (अपक्षय)
- Middle & lower course → meanders (घुमाव), oxbow lakes (अर्धचंद्राकार झीलें), deltas (डेल्टा).
🌟 Major Himalayan Rivers
- Indus (सिंधु)
- Ganga (गंगा)
- Brahmaputra (ब्रह्मपुत्र)
🌊 Indus River System (सिंधु नदी तंत्र)
- Origin: Tibet near Lake Mansarowar (मानसरोवर झील).
- Flows into India via Ladakh, forming scenic gorges.
- Passes Baltistan & Gilgit → Emerges at Attock.
- Tributaries (उप-नदियाँ): Zaskar, Nubra, Shyok, Hunza.
- Length: 2,900 km – one of the longest rivers in the world.
- Ends in Arabian Sea, east of Karachi.
🌊 Ganga River System (गंगा नदी तंत्र)
- Length: Over 2,500 km.
- Main Himalayan Tributaries: Yamuna, Ghaghara, Gandak, Kosi.
- Headwaters: Bhagirathi (भागीरथी) from Gangotri Glacier + Alaknanda at Devaprayag (देवप्रयाग).
- At Haridwar, enters plains.
- Splits: Bhagirathi-Hooghly flows to Bay of Bengal; main stream enters Bangladesh, joins Brahmaputra → becomes Meghna (मेघना).
🌊 Brahmaputra River System (ब्रह्मपुत्र नदी तंत्र)
- Origin: Tibet, east of Mansarowar.
- Longer than Indus, but mostly outside India.
- Flows east parallel to Himalayas → Namcha Barwa → sharp U-turn → Enters Arunachal Pradesh as Dihang (दिहांग).
- Tributaries: Dibang, Lohit, etc. in Assam.
🌱 Sundarban Delta (सुंदरबन डेल्टा)
- Named after Sundari tree (सुंदरी वृक्ष).
- Largest & fastest growing delta in the world.
- Habitat of the Royal Bengal Tiger 🐅.
🏞️ Peninsular Rivers (प्रायद्वीपीय नदियाँ)
- Mostly seasonal (मौसमी) – flow depends on rainfall.
- Shorter & shallower than Himalayan rivers.
- Many originate in Western Ghats → flow to Bay of Bengal.
- Some originate in Central Highlands → flow west.
🌟 Major Peninsular River Basins
- Narmada Basin (नर्मदा बेसिन)
- Tapi Basin (ताप्ती बेसिन)
- Godavari Basin (गोदावरी बेसिन)
- Mahanadi Basin (महानदी बेसिन)
- Krishna Basin (कृष्णा बेसिन)
Kaveri Basin (कावेरी बेसिन)
💧 The Narmada Basin (नर्मदा बेसिन)
- 🏞 Origin: Rises from Amarkantak Hills (अमरकंटक पर्वत) in Madhya Pradesh.
- 🪨 Flows westward in a rift valley (दरार घाटी) formed due to faulting.
- 🌅 Creates picturesque (मनोरम) spots —
- Marble Rocks near Jabalpur 🪨
- Dhuandhar Falls 🌊 plunging over steep rocks.
- 🛶 Tributaries: All are short & meet at right angles.
- 📍 Covers parts of Madhya Pradesh & Gujarat.
💧 The Tapi Basin (ताप्ती बेसिन)
- 🏞 Originates from Satpura Ranges (सतपुड़ा पर्वत), Betul district, MP.
- ↔ Flows parallel to Narmada in a shorter rift valley.
- 📍 Basin covers MP, Gujarat, Maharashtra.
- 🏖 Coastal plains between Western Ghats & Arabian Sea are narrow → Rivers short.
- 🌊 Main west-flowing rivers: Sabarmati, Mahi, Bharathpuzha, Periyar.
💧 The Godavari Basin (गोदावरी बेसिन)
- 🌄 Largest Peninsular River (दक्षिणी प्रायद्वीपीय नदी).
- 🏞 Originates from Western Ghats, Nasik (Maharashtra).
- 🌊 Drains into Bay of Bengal.
- 📍 Basin in Maharashtra (50%), MP, Odisha, Andhra Pradesh.
- 📏 Length: ~1500 km.
- 🌊 Tributaries: Purna, Wardha, Pranhita, Manjra, Wainganga, Penganga (last 3 are largest).
- 🏆 Also called Dakshin Ganga (Southern Ganga).
💧 The Mahanadi Basin (महानदी बेसिन)
- 🏞 Originates from Highlands of Chhattisgarh.
- 🌊 Flows through Odisha → Bay of Bengal.
- 📏 Length ~860 km.
- 📍 Basin in Maharashtra, Chhattisgarh, Jharkhand, Odisha.
💧 The Krishna Basin (कृष्णा बेसिन)
- 🏞 Rises from a spring near Mahabaleshwar.
- 📏 Length ~1400 km → Bay of Bengal.
- 🌊 Tributaries: Tungabhadra, Koyana, Ghatprabha, Musi, Bhima.
- 📍 Basin in Maharashtra, Karnataka, Andhra Pradesh.
💧 The Kaveri Basin (कावेरी बेसिन)
- 🏞 Rises from Brahmagiri Range, Western Ghats.
- 🌊 Meets Bay of Bengal south of Cuddalore, Tamil Nadu.
- 📏 Length ~760 km.
- 🌊 Tributaries: Amravati, Bhavani, Hemavati, Kabini.
- 📍 Basin in Karnataka, Kerala, Tamil Nadu.
🏞 Lakes (झीलें)
- 💧 Definition: Water stored in a trough (गर्त) on Earth’s surface.
🏔 Natural Freshwater Lakes
- Dal Lake (डाल झील)
- Bhimtal (भीमताल)
- Nainital (नैनीताल)
- Loktak (लोकटक)
- Barapani (बरापानी)
🏗 Man-made Lakes
- Govind Sagar (गोविंद सागर)
- Rana Pratap Sagar (राणा प्रताप सागर)
Nizam Sagar (निज़ाम सागर)
🌊 Importance of Lakes (झीलों का महत्व)
- 🎯 Provide recreation (मनोरंजन प्रदान करना)
- 🏞 Develop tourism (पर्यटन को बढ़ावा देना)
- 🐟 Maintain the aquatic system (जलजीव प्रणाली बनाए रखना)
- 🌺 Enhance natural beauty (प्राकृतिक सुंदरता बढ़ाना)
- 🌤 Moderate the climate (जलवायु को संतुलित करना)
- ☔ Prevent floods (बाढ़ रोकना) during rainy season
- ⚡ Source of hydel power (जलविद्युत का स्रोत)
- 💧 Maintain water flow (जल प्रवाह बनाए रखना) in summer
- 🌊 Regulate river flow (नदी के प्रवाह को नियंत्रित करना)
🏞 Role of Rivers in the Economy (अर्थव्यवस्था में नदियों की भूमिका)
- 🏛 Cradle of Civilisations – Many ancient civilisations developed on river banks.
- 🚰 Domestic & Industrial use (घरेलू और औद्योगिक उपयोग)
- 🚜 Irrigation (सिंचाई) for agriculture
- 🚢 Navigation (नौवहन) and transport
- ⚡ Hydroelectric power generation (जलविद्युत उत्पादन)
🚨 River Pollution (नदी प्रदूषण)
- 🗑 Domestic, municipal & industrial waste pollutes river water.
- 🏭 Untreated sewage (अशोधित सीवेज) and industrial effluents (औद्योगिक अपशिष्ट) reduce water quality.
- ❌ Self-cleansing capacity (स्वयं शुद्ध करने की क्षमता) of rivers decreases.
🏙 Urbanisation (शहरीकरण) increases river pollution.
