Six years of monitoring through the Mahurangi Land Restoration Programme shows strong scientific evidence that restoration measures have reduced fine sediment entering Mahurangi waterways. Restored streams recorded over 30 per cent less fine sediment than comparable streams flowing through open pasture.
Monitoring of the streams between 2023 and 2025 compared open pasture streams with fenced and planted waterways, as well as streams flowing through native forest. Results show that restoration work is making a significant difference, leading to healthier waterways, land and harbour ecosystems in the Mahurangi catchment area. Along with lower sediment, restored streams were found to have better habitat and fewer harmful mobile mud particles, which were twice as common in unrestored waterways.
The monitoring also recorded higher numbers of pollution-sensitive insects in restored streams, indicating improving ecological health.
The programme was delivered by Auckland Council and funded by the Ministry for the Environment in partnership with Ngāti Manuhiri Settlement Trust between 2020 and 2026. It built on the Mahurangi Action Plan, with a focus on reducing sediment entering waterways from rural land use, unsealed roads and development activity.
Councillor Richard Hills, Chair of Auckland Council's Policy, Planning and Development Committee, says this successful initiative to restore the Mahurangi for the benefit of all Aucklanders shows what happens when communities come together to achieve a goal.
“This mahi was the result of collaboration between local and central government, iwi, landowners, volunteers and community groups, who all played a significant role in the programme's success, contributing additional funding, voluntary labour and in-kind support.
“This huge effort over six years has helped protect streams, wetlands, springs, headwaters, coastal margins and native bush connected to waterways throughout the Mahurangi Harbour area for decades to come.”
Programme Manager Colleen Brent says the results highlight the value of long-term investment in catchment restoration.
"This monitoring gives us clear evidence that fencing and planting stream margins is making a difference. The improvements we are seeing are encouraging, but they also remind us that restoration takes time.
"The work done through this programme provides a strong foundation, and the continued commitment of landowners, community groups and local partners will be essential."
Eddie O’Kane, Kaitiaki Taiao for Manuhiri Kaitiaki Charitable Trust, says the programme reflects the importance of caring for the whenua and wai for future generations.
"For Ngāti Manuhiri, the health of the whenua and wai is inseparable from the wellbeing of the people who belong to and care for this place. This programme has helped bring mātauranga Māori and science together to protect the mauri of Mahurangi."
While the $6.15 million funded portion of the programme has now concluded, opportunities remain for rural landowners to continue restoration work through Auckland Council's Rural Waterway Protection Fund, which provides practical advice and co-funding for fencing, planting and stream restoration projects. The next funding round opens in September.