Koguna da tabkuna sune tushen samarda ruwa da kuma ban ruwa a duniya. Kusan 3% na ruwan dake bisa doron ƙasa yana da kyau a sha, yayin da sauran kuma na gishiri ne.
A wannan duniyar, af, rafuka mafi tsayi waɗanda aka keɓance gwargwadon tsayinsu da yankin da suka rufe sun yi fice. Saboda haka, idan mutum yana shirin a hutu a RashaDon haka dole ne ku more kyawawan halaye da namun daji na waɗannan rafuka.
Amur
Kogin Amur ko Heilong na ɗaya daga cikin koguna mafi tsayi a cikin Rasha. Sun kafa iyaka tsakanin Arewa Maso Gabashin China da Gabas ta Gabas ta Rasha. Tana da nau'ikan kifayen da suka fi tsayi mita 5,6. Tsawon kogin ya kai kilomita 2.824 (mil 1.755) kuma ya hau cikin tsaunukan Manchuria. Yawancin gadoji da ramuka an gina su tare da kogi don kulawa.
Yenisei
Yenisei shine kogi mafi girma wanda ya ratsa ta Tekun Arctic. Tsawon kogin ya kai kilomita 5.539 (mil 3.442) kuma mafi girman zurfinsa ya kai ƙafa 80 (mita 24) kuma matsakaiciyar zurfinsa ƙafa 45 (mita 14). Zurfin ruwan kogin yana da ƙafa 106 (mita 32), yayin da mashigar sa ƙafa 101 (m 31). Babban yanki na tsakiyar Siberia ya malale.
Ob
Kogin Ob Ob wanda aka fi sani da shi shi ne kogi mafi tsayi a Rasha kuma kogi na biyar mafi girma a duniya a gasar Kofin Duniya. Tana da babbar mashigar ruwa a duniya. Tsawon kogin ya kai kilomita 2.962 (mil 1.841) kuma ya samar da mil 16 kudu maso yamma na Biysk. Ana amfani da kogin galibi don samar da wutar lantarki da ruwa, ban ruwa da kuma kamun kifi. Hakanan ana amfani da yankin kogin don jigilar kaya ta jiragen ruwa tun zamanin da.