Umbala webhalansi egcina imvelo evulekayo Umbala wephansi evulekayo evulekayo, owaziwa nangokuthi ukhonkolo onezimbobo, ongaphezulu kwe-aggregate ehlanganisiwe embozwe ungqimba oluncane lwe-samente paste, i-aggregate kanye ne-samente paste ezihlanganiswe ndawonye ukuze kwakheke ukusatshalaliswa okufanayo kwe-pore.
Ukugcinwa kwebhalansi yemvelo yephansi lokuvikela imvelo elinombala, elaziwa nangokuthi "ukhonkolo olunezimbobo", ebusweni be-aggregate eqinile embozwe ungqimba oluncane lwe-paste yesimende, i-aggregate kanye ne-paste yesimende ezihlanganiswe ndawonye ukuze kwakheke ukusatshalaliswa okufanayo kwemigodi esakhiweni sezinyosi, ngakho-ke inomoya ovulekile, amanzi avulekile kanye nezici ezilula, iphakamisa ngempumelelo isimo sokugcwala kwamanzi futhi isuse ngempumelelo izingozi zokungcola kwemvelo njengezinto ezixubile zikawoyela emhlabathini. Kuyindlela enhle kakhulu yokugcina ibhalansi yemvelo yendawo. Iphansi elivulekile lisebenza ezindaweni zokuhamba ngezinyawo, ezigcawini zomphakathi, emapaki ezimoto avulekile, emigwaqweni emapaki, emigwaqweni yabahamba ngezinyawo yezentengiselwano, emigwaqweni yasemakhaya kanye neyasemagcekeni omphakathi njalo njalo.
