isiziba — isiZulu
Ingxenye yomhlaba lapho kungena khona umfula othile kanye nemingenela yawo. Le ndawo ihlukaniswa ezizibeni ezakhelene nayo wunqenqema lomhlaba ophakeme. Umngcele wesiziba ngumdladlathi noma imfunda yomfula (bheka i-“watershed”). Isiziba singathathwa njengohlelo oluvulekile lwezinto ezingenayo (inputs) (njengemvula kanye neqhwa elincibilikayo) ezithumela futhi zifake amanzi esizibeni kanye nezinto eziphumayo (outputs) (njengomhwamuko okhuphukayo namanzi aphumayo ayongena olwandle) ezikhipha amanzi kulolu hlelo. Kwenzeka izinqubo ezihlukahlukene esizibeni, okusho, ukuvimbeleka kwemvula ingafinyeleli emhlabathini (interception), ukugcinwa kwamanzi ngaphezu komhlaba (surface storage), ukungena kwamanzi emhlabathini (infiltration), ukumunceka kwamanzi emhlabathini (percolation), ukugcinwa kwamanzi ngaphansi komhlaba (groundwater storage), ukugeleza kwamanzi ngaphansi komhlaba (groundwater flow), ukugeleza kwamanzi ngaphezu komhlaba (overland flow), ukugcinwa komthamo othile wamanzi emgudwini wamanzi (channel storage) kanye nokugeleza kwamanzi emgudwini wamanzi (channel flow). Iziziba zakheke ngokwezimo ezihlukahlukene (morphometry) kanye nosayizi abahlukene futhi zinezici zobunjalo ezihlukene kakhulu. Ukufundwa nokucwaningwa kweziziba wumkhakha othile okhethekile ongaphansi kwamasayensi ahlukahlukene, kubandakanya neJografi. (Bheka i-“channelization”.)