N'ebe ugwu, mmiri ozuzo na-adịkarị ntakịrị, nke ihe dị ka 600 ruo 700 millimetres (24 ruo 28 in), edekọtara n'oge June-August. A na-ekwu na ọdịiche dị n'etiti oke osimiri na nke kacha nta n'ime oge ọkọchị na ọnwa akọrọ dị ka ihe dị ka ugboro 20. Osimiri Manas, nnukwu mmiri dị n'akụkụ ugwu ugwu nke Brahmaputra, edepụtara ihe ruru 7,641 cubic mita na-enye 5.48% nke ngụkọta nke Brahmaputra.
41,350 square kilomita (15,970 sq mi)