Isiteshi sikagesi samanzi lapho wonke noma iningi lamanzi akhiqiza amanzi ligcwele khona izakhiwo ezigcina amanzi emfuleni.

Iziteshi zikagesi zamanzi zohlobo lwedamu zibhekisela kakhulu eziteshini zikagesi zamanzi ezakha izakhiwo zokugcina amanzi emfuleni ukuze zakhe ichibi, zigxilise amanzi emvelo ukuze ziphakamise izinga lamanzi, futhi zisebenzise umehluko wekhanda ukukhiqiza ugesi. Isici esiyinhloko ukuthi idamu kanye nesitshalo sikagesi samanzi kugxile engxenyeni efanayo yomfula emfushane.
Iziteshi zikagesi zamanzi zohlobo lwedamu ngokuvamile zifaka izakhiwo zokugcina amanzi, izakhiwo zokukhipha amanzi, amapayipi okucindezela, izitshalo zikagesi, ama-turbine, amajeneretha kanye nemishini ehambisanayo. Iningi leziteshi zikagesi zamanzi ezinamadamu njengezakhiwo zokugcina amanzi ziyiziteshi zikagesi zamanzi ezisezingeni eliphakathi nendawo, kanti iningi leziteshi zikagesi zamanzi ezinamasango njengezakhiwo zokugcina amanzi ziyiziteshi zikagesi zamanzi ezisezingeni eliphansi. Uma ikhanda lamanzi lingaphakeme futhi umfula ubanzi, isitshalo sikagesi sivame ukusetshenziswa njengengxenye yesakhiwo sokugcina amanzi. Lolu hlobo lwesiteshi sikagesi lwamanzi lubizwa nangokuthi isiteshi sikagesi samanzi esiseceleni komfula, esiphinde sibe isiteshi sikagesi samanzi sohlobo lwedamu.
Ngokwendawo ehlobene yedamu kanye nesitshalo sikagesi wamanzi, iziteshi zikagesi wamanzi zohlobo lwedamu zingahlukaniswa ngezigaba ezimbili: uhlobo lwedamu kanye nosebe lomfula. Isitshalo sikagesi wamanzi sohlobo lwedamu sihlelwe ohlangothini olungezansi lomzimba wedamu, futhi amanzi adluliselwa ngepayipi lokucindezela ukuze kukhiqizwe ugesi. Isitshalo ngokwaso asithwali umfutho wamanzi ongaphezulu. Indlu kagesi, idamu, umzila ochithekayo kanye nezinye izakhiwo zesiteshi sikagesi wamanzi esingaphansi komfula zonke zakhiwe osebe lomfula. Ziyingxenye yesakhiwo sokugcina amanzi futhi zithwala umfutho wamanzi ongaphezulu komfula. Ilungiselelo elinjalo lisiza ekusindiseni utshalomali oluphelele lwephrojekthi.

Idamu lesiteshi sikagesi samanzi esingemuva kwedamu livame ukuba phezulu. Okokuqala, ikhanda eliphakeme lisetshenziselwa ukwandisa amandla afakiwe esiteshi sikagesi, okungazivumelanisa ngempumelelo nezidingo zokulawula ukuphakama kwesistimu kagesi; okwesibili, kunamandla amakhulu okulawula ukugeleza okuphezulu ukuze kuncishiswe ingcindezi yokulawula izikhukhula zomfula ongezansi; okwesithathu, izinzuzo eziphelele zibaluleke kakhulu. Ububi ukuthi ukulahlekelwa yizikhukhula endaweni yesitsha kuyanda futhi ukufuduka nokuhlala kabusha kwezakhamuzi zasemadolobheni nezasemakhaya kunzima. Ngakho-ke, iziteshi zikagesi zamanzi ezingemuva kwedamu ezinamadamu aphezulu kanye namachibi amakhulu zakhiwe kakhulu ezigodini eziphakeme zezintaba, izindawo ezinokungena kwamanzi amaningi kanye nezikhukhula ezincane.
Iningi leziteshi ezinkulu zamanzi ezakhiwe emhlabeni wonke ezingemuva kwedamu ligcwele ezweni lakithi. Esokuqala yiThree Gorges Hydropower Station, enekhono elifakiwe elingu-22.5 million kilowatts. Ngaphezu kwezinzuzo ezinkulu zokukhiqizwa kwamandla kagesi, iThree Gorges Hydropower Station nayo inezinzuzo eziphelele zokuqinisekisa ukulawulwa kwezikhukhula ezindaweni eziphakathi nezingezansi zoMfula iYangtze, ukuthuthukisa ukuhamba nokusetshenziswa kwemithombo yamanzi, futhi ibizwa ngokuthi “imishini esindayo yezwe.”