Ivili lamanzi
Ivili lamanzi ngumatshini wokuguqula amandla entshukumo yamanzi ahambayo okanye awayo abe ziindlela eziluncedo zamandla, kakhulukazi kwilitye lokusila lamanzi. Ivili lamanzi lenziwe livili elikhulu (elihlala lenziwe ngenkuni okanye ngentsimbi), elinamabala amaninzi okanye iibhakethi ezinamathele kumphetho wangaphandle ezenza indlela yokuqhuba. Amavili amanzi ayesasetyenziswa kwezorhwebo kude kube yinkulungwane yama-20, nangona engasasetyenziswa kakhulu namhlanje. Amavili amanzi asetyenziselwa ukusila umgubo kwiingqolowa zokusila , ukugaya inkuni zibeyintlama yokwenza iphepha, ukubhoboza isinyithi esenziwe ngesando, ukugaya, ukutyumza i-ore kunye nokugquma ifayibha ukuze isetyenziswe ekwenzeni ilaphu .
Eyona ngxaki inkulu yamavili amanzi kukuxhomekeka kwawo emanzini ahambayo, nto leyo ethintela indawo anokubekwa kuyo. Amadama anamhlanje ombane anokubonwa njengenzala yevili lamanzi, njengoko nawo esebenzisa ithuba lokuhamba kwamanzi ehla entabeni.