a distance of 229 km. before it confluence with Bhagirathi at Devprayag and constituting the Ganges, is the major river. The Alaknanda originates at a height of 3641 meters below Balakun peak 16 km. upstream from Badrinath form the two glaciers of Bhagirath Kharak and Satopanth. The two glaciers rise from the eastern slopes of Chaukhamba (7140 meters) peak, Badrinath peak and its satellite peaks. These peaks separates the Gangotri group of glaciers in the west. The major portion of the Alaknanda basin falls in Chamoli district. From its source up to Hallang (58 km), the valley is treated as upper Alaknanda valley. The remaining part of the area is known as lower Alanknanda valley. While moving from its source, the river flows in a narrow deep gorge between the mountain slopes of Alkapuri, from which it drives its name. All along its course, it drains its tributaries: Saraswati joins the Alaknanda 9 km downstream from Mana. Khir Ganga joins it below the Badrinath shrine and Bhyundar Ganga originated from Tipra glacier and Hemkund Sahib joins Alaknanda River at Govindghat after merging with River Pushpawati at Ghangaria. Dhauliganga meets at Vishnuprayag above Joshimath. The river Dhauliganga rises from the Nitti Pass at about 5070 meters. Its valley lies between the Kamet groups of peaks in the west and Nandadevi group in the east. The Dhauli takes a northern course at Malari. Between Malari and Tapovan, it is almost a narrow gorge with perpendicular cliffs on either side. several thousand meters high. the Dhauliganga in its turn is fed by GirthiGanga at Kurkuti and Rishiganga 500 metres below Reni. Downstream small tributaries – Helang, Garud, Patal and Birahiganga join the Alaknanda between Joshimath and Chamoli. Nandakini, which rises from Semudra Glaciers drainage the western slopes of Trishul mountains, joins it at Nandprayag. Southeast, river Pindar joins the Alaknanda at Karnprayag. The Pindar river is fed by the Milam and Pindar glacier from the Nandadevi group of glacier. The Pindar river, before joining Alaknanda, is fed by Kaliganga and Bheriganga. The rivers of Chamoli district, generally flow with great force in steep and narrow channels often resulting in excessive erosion and collapse of the banks. Nanda Devi glacier flood On 7 February 2021 a part of Nanda Devi, a Himalayan glacier, broke away at Joshimath. This caused water levels in the Rishiganga and Dhauliganga rivers to rise. One dam at the Rishiganga