Wairoa District Council says guaranteeing the protection and enhancement of a river at Mahia Peninsula is the result of more than a year of consultation and discussion.
The council on Saturday signed a memorandum of understanding with Hawke's Bay Regional Council, trustees from four marae and landowners of the Whangawehi River catchment.
The district council says the agreement means all parties will work towards developing a management plan for the river.
Engineering manager Neil Cook says plans for a wastewater scheme within the river catchment will include the opportunity for local Maori to help develop the scheme.
A spokeperson for Tuahuru Marae, where the agreement was signed, says guaranteed protection of what's regarded as a sacred river is significant.