Write a note on Ganga river system.
The Ganga river system consists of the master river Ganga and a large number of its tributaries. This system drains a very large area comprising the middle part of the Himalayas in the north, the northern part of the Indian Plateau in the south and the Ganga Plain in-between. The total area of the Ganga basin in India is 861,404 sq km which accounts for 26.3 per cent of the geographical area of the country.This basin is shared by ten states. These states are Uttaranchal and Uttar Pradesh (34.2%), Madhya Pradesh and Chhattisgarh (23.1%), Bihar and Jharkhand (16.7%), Rajasthan (13.0%), West Bengal (8.3%), Haryana (4.0%) and Himachal Pradesh (0.5%). The Union Territory of Delhi accounts for 0.2% of the total area of the Ganga Basin.
The Ganga originates as Bhagirathi from the Gangotri glacier in Uttar Kashi District of Uttaranchal at an elevation of 7,010 m. Alaknanda joins it at Devaprayag. But before Devaprayag it reached, the Pindar, the Mandakini, the Dhauliganga and the Bishenganga rivers pour into the Alaknanda and the Bheling flows into the Bhagirathi.
The Pindar River rising from Nanda Devi and East Trisul (6,803 m) joins Alaknanda at Karan Prayag and Mandakini or Kali Ganga meets at Rudra Prayag. The combined water of the Bhagirathi and the Alaknanda flows in the name of the Ganga below Devaprayag.
After travelling 280 km from its source, the Ganga reaches Haridwar, debouches from the hills and enters plain area. From here it flows in south and south-east direction for a distance of 770 km to reach Allahabad. Here it is joined by the Yamuna which is its most important tributary.It sweeps another 300 km eastwards to reach the Bihar plain. Near Rajmahal Hills it turns to the southeast and south of Farraka, it ceases to be known as the Ganga. It bifurcates itself into Bhagirathi-Hugli in West Bengal and Padma-Meghna in Bangladesh. After traversing 220 km further down in Bangladesh, the Brahmaputra (or the Jamuna as it is known here) joins it at Goalundo and after meeting Meghna 100 km downstream the Ganga joins the Bay of Bengal.
Before entering the Bay of Bengal, the Ganga, along with Brahmputra, forms the largest delta of the world between two arms: the Bhagirathi / Hugli and the Padma / Meghna covering an area of 58,752 sq km.
The delta front of the Ganga is a highly indented area of about 400 km length extending from the mouth of the Hugli to the mouth of the Meghna. The delta is made of a web of distributaries and islands and is covered by dense forests called the Sunderbans. A major part of the delta is a low- lying swamp which is flooded by marine water during high tide.
The total length of the Ganga River from its source to its mouth (measured along the Hugli) is 2525 km, of which 310 km in Uttaranchal, 1,140 km in Uttar Pradesh, 445 km in Bihar and 520 km in West Bengal. The remaining 110 km stretch of the Ganga forms the boundary between Uttar Pradesh and Bihar. The river flows majestically from Gangotri to Bay of Bengal with an average gradient of 9.5 cm per km.