He mātātaki nui te whakamahi i ngā pūnaha wai i runga i ngā pāmu hei āwhina i ngā rākau kia puawai. He kī tēnei ko te 'center pivot irrigation system' te ingoa mō te pūnaha wai roa. Ko te pūnaha wai roa rawa o te ao he nui noa, ā, āwhina hoki i ngā kaihoko kai ki te whakapuakihia ngā kai i te nuinga.
Ko te kaupapa o te pūnaha wai 'center pivot' roa rawa o te ao e āhei ana ki te whakawai i ngā rākau i rohe potonga nui. E āhei ana ki te wāhi i te 2 mīra ki te roa. Koia nei pērā i te haere tonu i roto i te pāmu nui rawa. Kia whakarerekē te pūnaha wai i roto i te potonga, me te whakatakoto i runga i ngā rākau. Me te whakatipuritanga tuatahi, ka taea te whakapuakitanga i ngā rākau ki te rite.
Ko te rākau tuatahi, ko te rākau e tūhono ana i ngā whenua ka huringa, e awhina ana i ngā moutere ki te whakapai i te kai. Ki te whakamahi i tēnei pūnaha nui o te wai, ka whakapai ngā moutere i ngā hua whenua i runga i te whenua nui. Ko tēnei e whakaae ana ki a rātou kia hokohoko atu i te nui o te kai ki ngā tāngata o te wā. Te Whakamātau Wai Pūtahi ko te pūnaha nui e āwhina ana i ngā moutere ki te whakatōhu moni me te kai mō te nuinga o ngā tāngata.
Ka orooro te rākau tuatahi ki ngā tīeke kei te waho. Ka tae ki ngā tīeke i te taha o ngā rua mīra mai i te maru! He nui noa te haere mō te whakahaere wai. Ko te rākau roa o te whakahaere tuatahi Rārangi Whakamahi Wai e mārama ana i ngā hauketo ki te whakatipu kai mai i ngā pūhā wairua nui, ki te mea kaore i te whakarerekētanga o te pūnaha.
Ki runga i te rākau tae roa a Gengze he maha ngā wāhi e mahi ana hei whakawehi i ngā tipu. He rākau roa te āhua o te wāhi e kawe ana i ngā paemahi wai. Ka whitiwhiti te rākau i waenganui i ngā rata kei te waho. He rīpora ngā rata, no reira ka mahi tonu te pūnaha i waenganui i te whenua. Whanui pūnaha wai i te tuatahi ka hangaia e ngā paihikara hei whai mana, hei tū tonu mo te wā e tae nei.
Ka ora ai ngā tipu ki te whakamahere haumaru ake i te wai. Ka haere tonu te pūnaha i waenganui i te mara, ka taea te whakarite i te wai mō ngā tipu katoa. Me whai wai rawa ngā tipu ki te whakatipu, ko tēnei rākau e awhina ana i ngā tipu ki te ora. Ka whakarongo ngā hauketo ki te pūnaha whakawehi hei whakatika i te whakatipu o ngā tipu, kia tupu ora ai, kia puta mai iho i te maha kai.