SUSTAINABLE
MANGAWHAI
THE SUSTAINABLE MANGAWHAI PROJECT.
The harbour lies at the heart of the Mangawhai community. It underpins the growth of our town, the well-being of its residents and businesses, and its appeal to holidaymakers. It also
supports significant biodiversity, including regionally and nationally important seabird populations.
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The Community Survey undertaken by Mangawhai Matters in 2021 confirmed that for both residents and visitors, the significance of the coastal environment was overwhelming. The character of the town is shaped by the physical environment.
Mangawhai Matters Society Inc looking into the future of Mangawhai Harbour, the threats it faces, and how these might be managed in the future. The first of these are published below.
Stage One - Scoping the Issues
Mangawhai Harbour and Spit
Published October 2023
(Corrected version, 14 November 2023)
The Summary Report sets out the main findings of Stage One of the Sustainable Mangawhai Project. It considers the implications of a more volatile climate and sea level rise for the harbour and spit based on the study of the coastal physical processes acting on them conducted by Dr Terry Hume.
In light of the significance of the recreational services identified with the harbour and coast, outlined in the accompanying Research Notes, the Summary Report also canvases the sorts of policy measures that might mitigate those threats. It suggests that these can be best advanced by the agencies responsible for managing the harbour working together to develop and act on a comprehensive long-term plan.
Coastal physical processes and management
Published August 2023
Mangawhai Matters is pleased to provide a comprehensive report on the coastal processes affecting our harbour and spit prepared by Dr Terry Hume, Environmental Consultant – Coasts. It identifies the threats they face, and management options for responding to them. The report covers the impact of ocean storms and currents, the dynamics of dune development and sand movement, tidal flows, bank erosion, and water quality.
Community and Economy
Visitors and Retail Spending
Published October 2023
This research note outlines retail spending in Mangawhai over the five years to March 2023. It highlights the important contribution of spending in Mangawhai stores by visitors.
Recreation in Mangawhai
Published October 2023
This research note reports on a survey undertaken in summer and autumn 2023 of visitors in Mangawhai to illustrate why they visit and holiday in Mangawhai.
Quantifying the Benefits of Visiting Mangawhai
Published October 2023
This research note looks at what it costs people visit and stay in Mangawhai as an indication of the value the place on the experience. It includes information on length of stay and size of visiting group organised by type of accommodation. It also identifies the value of second homes and dwellings with immediate access to the shoreline and its views to indicate the residential investment made to access the recreational opportunities available.
Managing our Harbour
Published October 2023
This note identifies what the agencies responsible for managing the Mangawhai Harbour and the distal spit spend on an annual basis to do so.
Stage Two - Where to from here?
Stage One identified three significant threats to the harbour and coast and, consequently, to the enjoyment of visitors and residents, and to the prosperity of the community. These are coastal inundation, further damage to and a potential breach of the spit, and threats to the harbour water quality.
In Stage Two, Mangawhai Matters intends to refine our understanding of just how significant these threats are, and under what circumstance critical threshold might be reached. It is hoped that Kaipara District and Northland Regional councils, and the Department of Conservation with its environmental mandate and management responsibility for the spit, will work with the community on these matters.
We also expect that the information collected to date will need to be refined with respect to the physical processes and extended to account for the ecological impacts of the threats identified.
It will be necessary to gather data and develop models of tidal flows and sand movement given the physical structure of the harbour under different conditions, including in particular storm surge and high tidal movements. It will be important to understand the sediment transported into the harbour from run-off in severe rainstorms of the sort we experienced in February 2023, especially if these become more frequent.
It is important to understand the ecological impacts of the sorts of changes to the harbour, spit, and coast that extreme events might bring about, either individually or cumulatively. An understanding of impacts on biodiversity should further highlight the need for a comprehensive plan. It may also inform the way the way it should be implemented.
Mangawhai Matters is currently exploring avenues for commissioning and funding expert investigation of these matters with independent scientific advisors.