Explanation:

Supplementary notes: Brahmaputra River System :

• The Brahmaputra Valley has an average width of about 80 Km. The main river of the valley, Brahmaputra is one of the largest rivers in the world and rank fi fth with respect to its average discharge.
• The river originates from the Kailash ranges of Himalayas at an elevation of 5300 M. After fl owing through Tibet it enters India through Arunachal Pradesh and fl ows through Assam and Bangladesh before it joins Bay of Bengal.
• The catchments area of Brahmaputra in Tibet is 2, 93,000 Sq. Km; in India and Bhutan is 2,40,000 Sq. Km and in Bangladesh is 47,000 Sq. Km. The Brahmaputra basin extends over an area of 5,80,000 Sq. Km up to its con fl uence within Bangladesh.
• The most predominant soil type found in the sub-basin is the red loamy soil and alluvial soil. Other important soil types are sandy, loamy, clayey soils, their combinations and laterite soils.
• All the tributaries of the valley area are rain fed and foam up with rain. The precipitation here is mainly due to South West monsoon. Heavy precipitation occurs here from May to September.
• All its tributaries experience number of fl ood waves as per rainfall in respective catchments. If the fl ood of the tributaries coincides with the fl ood of Brahmaputra, it causes severe problem and devastation.