Te Ātiawa and the Kāpiti District Council have signed an agreement to work in partnership on water and its management in the rohe.
The Te Āti Awa ki Whakarongotai Water Working Group will now work with the council to explore how to manage water in a culturally appropriate way within the Waikanae, Paraparaumu and Raumati catchment.
The iwi and the council recently launched the 'River Recharge Scheme', which uses traditional Māori scientific knowledge to oxygenate the river with tuna, or eels.
The chair of the working group, Bill Carter, said it confirmed the important role iwi played as kaitiaki of natural resources.
"We saw there was a position as Treaty partners for the three [local iwi] of us having a joint responsibility," Mr Carter said.
"So that the progress of the River Recharge project was jointly managed by an adaptive management committee comprising representatives of the Wellington Regional Council, the Kāpiti Coast District Council and the Te Ātiawa ki Whakarongotai Water Group."
Kāpiti Coast District mayor Ross Church said tribal involvement in the scheme was an important step forward as tāngata whenua brought valuable knowledge and a guardianship role to the table.
Mr Church said the Te Āti Awa working group and the iwi as a whole had an immensely valuable role in the plan to revitalise the river, as well as the contribution of their knowledge and cultural advice.
He said it was the iwi who suggested the "tuna" (eels) as a way of aerating the water, removing gases, and oxygenating the water by putting it over a waterfall before it meets the river.
"Adding 400-year-old aquifer water is more than just a practical solution, it's one that demonstrates the spiritual significance of caring for the awa [river], and nurtures the area's most precious resource - water."
Mr Church said it was important to recognise publicly how much the council values the contribution of the Te Āti Awa ki Whakarongotai Water Working Group and Te Ātiawa.
He said their partnership on the River Recharge Scheme reflected the vibrant, thriving and diverse Kāpiti the council's seeking to create via its long-term plan.
The chair of Te Āti Awa ki Whakarongotai Water Working Group Bill Carter said arrangements such as this build on top of the long-standing 20-year relationship local iwi have with the council which they're also very proud of.