A cikin hotuna, magudanar ruwa, raba ruwa, raba, tsaunuka, magudanar ruwa, rabuwar ruwa ko tsayin ƙasa wani yanki mai tsayi wanda ke raba magudanan magudanan magudanan ruwa . A kan ƙaƙƙarfan ƙasa, rabe-raben ya ta'allaka ne tare da ƙwanƙolin yanayi, kuma yana iya kasancewa cikin nau'in tsaunuka ko tsaunuka guda ɗaya, wanda aka sani da kewayon rarraba . Kuma A kan ƙasa mai faɗi, musamman inda ƙasa ke da marsshiri, rarrabuwar na iya zama da wahala a gane. Rarraba sau uku aya ce, sau da yawa taron koli, inda magudanan ruwa guda uku suka hadu. Rarraba benen kwarin ƙananan magudanar ruwa ne wanda ke ratsa rafin, wani lokaci ana ƙirƙira shi ta hanyar ajiyewa ko kama rafi . Sannan wasu Kuma Manyan rabe-raben raba rafukan da ke zubewa zuwa tekuna ko tekuna daban-daban ana kiransu continental division. Ana amfani da kalmar tsayin ƙasa a Kanada da Amurka don komawa zuwa rarraba magudanar ruwa. Ana amfani dashi akai-akai a cikin kwatancen kan iyaka, waɗanda aka saita bisa ga " koyaswar iyakokin halitta ". A cikin wuraren da ke da glacied sau da yawa yana nufin ƙananan wuri akan rarrabuwa inda za'a iya jigilar kwale -kwale daga tsarin kogin zuwa wancan.