ka ... ana
1. (particle) when, whenever.
(Te Māhuri Textbook (Ed. 2): 63-64;)
Ka waipuke ana tēnei awa, ka mauria mai he oneone parakiwai o ngā whenua mōmona o runga, ka rukea ki runga i tō mātau whenua hai whakamōmona (HP 1991:14). / When this river flooded it brought down silt of the rich lands upstream and deposited it on our land to enrich it.