🌊 Drainage – जल निकासी प्रणाली (Class 9 SST, Hinglish Notes)
🌟 1. Introduction – परिचय
📌 Drainage ka matlab hai – River system of an area.
- Drainage Basin (नदी बेसिन): वह क्षेत्र jahan ki सारी छोटी नदियाँ aur नाले मिलकर ek main river me girte hain jo finally sea/lake/ocean me drain hoti hai.
- Water Divide (जल विभाजक): कोई भी उँचाई (mountain/upland) jo दो drainage basins ko separate karti hai.
💡 Example: Ambala is a water divide between Indus & Ganga river systems.
🇮🇳 2. Drainage System in India – भारत की नदी प्रणालियाँ
India ki rivers do main groups me divided hain:
1️⃣ Himalayan Rivers (हिमालयी नदियाँ) – Perennial 🌧️ + Snowmelt ❄️
2️⃣ Peninsular Rivers (प्रायद्वीपीय नदियाँ) – Seasonal 🌦️ Rain dependent
🏔️ 3. Himalayan Rivers – हिमालयी नदियाँ
- Features:
- Perennial (पूरे साल पानी)
- Snowmelt + Rainwater se banti hain
- Long course, gorges, meanders, oxbow lakes, aur delta banati hain
- Major rivers: Indus, Ganga, Brahmaputra
- Tributaries: Yamuna, Ghaghara, Kosi, Gandak
3.1 Indus River System – सिंधु नदी तंत्र
- Origin: Tibet, Lake Mansarowar ke paas
- India me entry: Ladakh (Gorge banati hai)
- Tributaries: Zaskar, Shyok, Nubra, Hunza
- Punjab Rivers: Satluj, Beas, Ravi, Chenab, Jhelum → Pakistan me Indus se milti hain
- Length: 2900 km (world ke sabse lambi rivers me se ek)
- Indus Water Treaty 1960: India sirf 20% water use kar sakta hai (Punjab, Haryana, Rajasthan irrigation ke liye)
3.2 Ganga River System – गंगा नदी तंत्र
- Headstreams:
- Bhagirathi – from Gangotri Glacier
- Alaknanda – Dono Devaprayag me milkar Ganga banti hai
- Tributaries:
- From Himalayas: Yamuna, Ghaghara, Gandak, Kosi (flood-prone)
- From Peninsular: Chambal, Betwa, Son (short & less water)
- Delta: Sundarban Delta 🌿
- Formed by Ganga + Brahmaputra
- Largest & fastest growing delta
- Home of Royal Bengal Tiger 🐅
3.3 Brahmaputra River System – ब्रह्मपुत्र नदी तंत्र
- Origin: Tibet, Mansarowar ke east (Tsang Po)
- India me entry: Arunachal Pradesh (Dihang naam se)
- Tributaries: Dibang, Lohit
- Features:
- Assam me braided channel
- Riverine islands banata hai (Majuli – sabse bada river island)
- Monsoon me flood-prone
🏞️ 4. Peninsular Rivers – प्रायद्वीपीय नदियाँ
- Features:
- Mostly seasonal (rain dependent)
- Shorter & shallower course
- Most flow eastwards → Bay of Bengal (delta banate hain)
- Some flow westwards → Arabian Sea (estuary banate hain)
Major Basins:
1️⃣ Narmada – Origin: Amarkantak Hills (M.P.) → Rift valley → Arabian Sea
- Famous: Marble Rocks, Dhuadhar Falls
2️⃣ Tapi – Origin: Satpura Hills (M.P.) → Rift valley → Arabian Sea
3️⃣ Godavari (Dakshin Ganga) – Origin: Nasik (Maharashtra), 1500 km
- Tributaries: Purna, Wardha, Manjra, Wainganga
4️⃣ Mahanadi – Origin: Chhattisgarh → Odisha → Bay of Bengal
5️⃣ Krishna – Origin: Mahabaleshwar (Maharashtra), 1400 km
- Tributaries: Bhima, Tungabhadra, Koyna
6️⃣ Kaveri – Origin: Brahmagiri Hills (Karnataka) → Tamil Nadu
- Famous: Shivasamudram Falls, HEP supply to Bengaluru & Mysuru
🏞️ 5. Lakes – झीलें
- Importance:
- Flood control 🌊
- Irrigation & Hydel power ⚡
- Tourism & Beauty 🛶
- Types:
- Natural Lakes: Dal, Nainital, Wular (tectonic), Loktak
- Saltwater Lakes: Sambhar (Rajasthan)
- Artificial Lakes: Gobind Sagar (Bhakra Nangal)
💰 6. Role of Rivers in Economy – नदियों का आर्थिक महत्व
- Irrigation for agriculture 🌾
- Hydroelectric power ⚡
- Navigation & transport ⛴️
- Tourism & fisheries 🎣
⚠️ 7. River Pollution – नदी प्रदूषण
- Causes:
- Domestic sewage 🏠
- Industrial effluents 🏭
- Agricultural runoff 🌾
- Effect:
- Water quality down, health issues, aquatic life danger
- Programs:
- Ganga Action Plan 1985
- National River Conservation Plan 1995
✅ Summary for Students:
- India me 2 major drainage systems hain: Himalayan & Peninsular
- Himalayan rivers perennial & long, Peninsular rivers seasonal & short
- Rivers & lakes economy ke liye bohot important hain
- River pollution serious problem hai, iske liye government ne plans shuru kiye hain