Flood mitigation options
What other flood mitigation options have been considered?
As many as 18 flood mitigation options have been considered, some with further variations. These include stopbanks, floodways, dredging, bar structures and management, drain clearing, dams, reforestation, temporary flood barriers and house raising.
These options were developed with input from the Wairoa community, whose kōrero and lived experience helped to develop the initial list of potential flood mitigation options.
As many as 18 flood mitigation options have been considered, some with further variations. These include stopbanks, floodways, dredging, bar structures and management, drain clearing, dams, reforestation, temporary flood barriers and house raising.
These options were developed with input from the Wairoa community, whose kōrero and lived experience helped to develop the initial list of potential flood mitigation options.
Why is dredging not being considered?
Dredging was previously considered as an option but has some significant limitations and is therefore no longer considered to be an option for reducing North Clyde flooding. The main limitations associated with dredging include the high likelihood that sediment would redeposit in the river after dredging has occurred therefore requiring ongoing dredging, the negative effects associated with disturbance of the riverbed, including ecological impacts, and the extremely expensive costs associated with dredging, estimated to be $990 million in the immediate term, with a further $130 million per year in maintenance.
Dredging was previously considered as an option but has some significant limitations and is therefore no longer considered to be an option for reducing North Clyde flooding. The main limitations associated with dredging include the high likelihood that sediment would redeposit in the river after dredging has occurred therefore requiring ongoing dredging, the negative effects associated with disturbance of the riverbed, including ecological impacts, and the extremely expensive costs associated with dredging, estimated to be $990 million in the immediate term, with a further $130 million per year in maintenance.
Why is house raising not being considered?
House raising was previously considered as an option too, but also has some significant limitations including the fact that not all properties can be raised, and there would still be damage to ground level assets and belongings, there would be no flood protection for marae, urupā, and local businesses, and there are very high costs associated with raising all of the affected buildings that can be raised. Additionally, the Government’s $70 million has been ring-fenced specifically for community scale flood mitigation and cannot be used to cover the costs of raising individual properties.
House raising was previously considered as an option too, but also has some significant limitations including the fact that not all properties can be raised, and there would still be damage to ground level assets and belongings, there would be no flood protection for marae, urupā, and local businesses, and there are very high costs associated with raising all of the affected buildings that can be raised. Additionally, the Government’s $70 million has been ring-fenced specifically for community scale flood mitigation and cannot be used to cover the costs of raising individual properties.
Why isn’t Wairoa River Bar management being considered?
The flood modelling indicates that the Bar does not influence flooding levels upstream of the State Highway 2 (SH2) bridge. This is because the river upstream of the bridge is slightly higher than the sea and Bar levels.
The Bar does, however, influence flood levels of the Wairoa township downstream of the SH2 bridge, and longer-term solutions to more effectively manage the Bar are currently being considered as part of the broader, holistic approach to flood plain management for Wairoa.
It is worth noting that the Hawke’s Bay Regional Council has a new operational management plan for the Wairoa River Bar – a plan that was established in November 2024.
The flood modelling indicates that the Bar does not influence flooding levels upstream of the State Highway 2 (SH2) bridge. This is because the river upstream of the bridge is slightly higher than the sea and Bar levels.
The Bar does, however, influence flood levels of the Wairoa township downstream of the SH2 bridge, and longer-term solutions to more effectively manage the Bar are currently being considered as part of the broader, holistic approach to flood plain management for Wairoa.
It is worth noting that the Hawke’s Bay Regional Council has a new operational management plan for the Wairoa River Bar – a plan that was established in November 2024.
Why is Kopu Road not being protected?
Following the June 2024 flooding event and Lawrence Yule’s appointment as Crown Manager in August, the scope of the Project has broadened to include potential flood mitigation options for Kopu Road.
Further work to determine the most technically viable solutions for Kopu Road is ongoing. This includes looking at longer-term solutions to manage the Wairoa River Bar more effectively.
Following the June 2024 flooding event and Lawrence Yule’s appointment as Crown Manager in August, the scope of the Project has broadened to include potential flood mitigation options for Kopu Road.
Further work to determine the most technically viable solutions for Kopu Road is ongoing. This includes looking at longer-term solutions to manage the Wairoa River Bar more effectively.
Has a Wairoa River survey been done?
Hawke’s Bay Regional Council completed a river survey of the lower end of the Wairoa River after Cyclone Gabrielle in 2023, and a survey of the river up to Frasertown in August 2024.
Hawke’s Bay Regional Council completed a river survey of the lower end of the Wairoa River after Cyclone Gabrielle in 2023, and a survey of the river up to Frasertown in August 2024.
Will there be another review of preferred Option 1C, or is there room to adjust the option based on feedback from affected residents?
There may be room to adjust the final footprint of Option 1C based on feedback – this is the reason we have been engaging with both potentially impacted whānau, land and property owners and the wider community.
It is important to note that Hawke’s Bay Regional Council’s February 2025 decision to progress Option 1C was made on the basis that the profile and alignment of the floodway is further refined first, in order to further minimise potential impacts to owners of whenua Māori, whānau, home and landowners.
There may be room to adjust the final footprint of Option 1C based on feedback – this is the reason we have been engaging with both potentially impacted whānau, land and property owners and the wider community.
It is important to note that Hawke’s Bay Regional Council’s February 2025 decision to progress Option 1C was made on the basis that the profile and alignment of the floodway is further refined first, in order to further minimise potential impacts to owners of whenua Māori, whānau, home and landowners.
How does Option 1C integrate with other environmental or infrastructure improvements to minimise flooding risk?
Whilst Option 1C focuses on providing more immediate flood mitigation solutions for Wairoa (once constructed), this option is only one part of a more holistic approach to overall flood plain management and would likely sit alongside other initiatives including the ongoing management of the Wairoa River Bar and the maintenance of existing water infrastructure across Wairoa.
Other environmental or infrastructure improvements may also be considered to assist with reducing the risk to flooding, however some of these may be longer-term solutions and may take some time before benefits are seen.
Whilst Option 1C focuses on providing more immediate flood mitigation solutions for Wairoa (once constructed), this option is only one part of a more holistic approach to overall flood plain management and would likely sit alongside other initiatives including the ongoing management of the Wairoa River Bar and the maintenance of existing water infrastructure across Wairoa.
Other environmental or infrastructure improvements may also be considered to assist with reducing the risk to flooding, however some of these may be longer-term solutions and may take some time before benefits are seen.
How was community input considered in developing these options? Will there be additional community consultation?
Recognising that the people of Wairoa know the whenua (land) and awa (river) best, back in June 2023, a series of hui were held asking local people what they knew of the river and its patterns, what they saw and experienced during Cyclone Gabrielle, and what they thought might work best for the future.
From these kōrero, a long list of potential flood mitigation options was developed and further considered from an engineering perspective.
In October 2023, a Wairoa Flood Mitigations Scheme Stakeholder Group was established by the Tripartite partners, and included mana whenua and marae representatives, farmers, local businesses, and people whose homes and properties were impacted by Cyclone Gabrielle. You can find the Terms of Reference for this Stakeholder Group on the Wairoa Flood Mitigation Stakeholder Group Resources Page.
Together, this Stakeholder Group worked with river engineers, other technical experts and mana whenua over an eight-month period to consider each potential option in more detail. The minutes of each of these Stakeholder Group meetings, as well as the various technical and engineering reports provided to the Group, can also be found on the Peer Reviews and Technical Reports Resources Page.
Some of the questions asked during this process included:
Recognising that the people of Wairoa know the whenua (land) and awa (river) best, back in June 2023, a series of hui were held asking local people what they knew of the river and its patterns, what they saw and experienced during Cyclone Gabrielle, and what they thought might work best for the future.
From these kōrero, a long list of potential flood mitigation options was developed and further considered from an engineering perspective.
In October 2023, a Wairoa Flood Mitigations Scheme Stakeholder Group was established by the Tripartite partners, and included mana whenua and marae representatives, farmers, local businesses, and people whose homes and properties were impacted by Cyclone Gabrielle. You can find the Terms of Reference for this Stakeholder Group on the Wairoa Flood Mitigation Stakeholder Group Resources Page.
Together, this Stakeholder Group worked with river engineers, other technical experts and mana whenua over an eight-month period to consider each potential option in more detail. The minutes of each of these Stakeholder Group meetings, as well as the various technical and engineering reports provided to the Group, can also be found on the Peer Reviews and Technical Reports Resources Page.
Some of the questions asked during this process included:
- What option/s will offer the community of Wairoa the best flood mitigation?
- What impacts will each option have – on people and their homes, land, businesses and livelihoods, as well as things like marae, urupā and cultural taonga?
- How much will each option cost?
- What matters most to our community?
Acknowledging that no unanimous agreement on preferred flood mitigation options could be reached amongst the Stakeholder Group members, the decision was made to take the conversation to the Tripartite partners for further discussion and consideration.
In October 2024, the Tripartite partners agreed to support the commencement of early engagement with mana whenua, including potentially impacted whānau and property owners, with this engagement covering both Options 1C and 1D and all other options that were previously considered.
The preferred Option 1C is being progressed on the basis that the profile and alignment of the floodway is further refined first, in order to further minimise potential impacts to owners of whenua Māori, whānau, home and landowners.
It is important to note that a preferred flood mitigation solution is only one part of the process, and there is more important mahi ahead for us all, with the final decision to be made by the Government.
The Project team will move through a period of focussed engagement with home and landowners, including owners of whenua Māori, to understand the position of all whānau and to further discuss the land access required to deliver flood mitigation for Wairoa.
Broader community consultation will also take place, including on longer-term solutions for the Wairoa River Bar and Kopu Road.
In October 2024, the Tripartite partners agreed to support the commencement of early engagement with mana whenua, including potentially impacted whānau and property owners, with this engagement covering both Options 1C and 1D and all other options that were previously considered.
The preferred Option 1C is being progressed on the basis that the profile and alignment of the floodway is further refined first, in order to further minimise potential impacts to owners of whenua Māori, whānau, home and landowners.
It is important to note that a preferred flood mitigation solution is only one part of the process, and there is more important mahi ahead for us all, with the final decision to be made by the Government.
The Project team will move through a period of focussed engagement with home and landowners, including owners of whenua Māori, to understand the position of all whānau and to further discuss the land access required to deliver flood mitigation for Wairoa.
Broader community consultation will also take place, including on longer-term solutions for the Wairoa River Bar and Kopu Road.
How have cultural considerations and the views of mana whenua been factored into this process?
A Cultural Impact Assessment (CIA) was produced to identify cultural impacts and how proposed options can avoid, remedy and/or mitigate cultural impacts. There was a comprehensive process for developing the CIA which involved:
A Cultural Impact Assessment (CIA) was produced to identify cultural impacts and how proposed options can avoid, remedy and/or mitigate cultural impacts. There was a comprehensive process for developing the CIA which involved:
- Engagement with whānau, both in person and online,
- Review of personal research, articles and reports, and
- Review of technical reports to better assess the possible cultural impacts in each of the options.
Has the Cultural Impact Assessment (CIA) been publicly released?
A CIA documents many forms of mātauranga, including cultural values, wāhi tapu, whakapapa, taonga and potential impacts related to a kaupapa. While it informs decision-making, it is not a public document; it is prepared for a specific purpose and audience and, although it was commissioned by Hawke’s Bay Regional Council, it does not belong to Regional Council.
Mātauranga Māori remains the intellectual and cultural property of Māori, and we must respect the willingness of those who have contributed culturally sensitive information, and who have an expectation that it is treated respectfully and with care.
Whilst the full CIA is not a public document, the Whakarāpopototanga o ngā Tūtohu (Summary of Recommendations) for proposed flood mitigation options 1C and 1D is available on the Cultural Impact Assessment Resources Page of this website.
Please note, the Project team recognise mātauranga Māori exists in many places and forms and remain very open to receiving further cultural input.
A CIA documents many forms of mātauranga, including cultural values, wāhi tapu, whakapapa, taonga and potential impacts related to a kaupapa. While it informs decision-making, it is not a public document; it is prepared for a specific purpose and audience and, although it was commissioned by Hawke’s Bay Regional Council, it does not belong to Regional Council.
Mātauranga Māori remains the intellectual and cultural property of Māori, and we must respect the willingness of those who have contributed culturally sensitive information, and who have an expectation that it is treated respectfully and with care.
Whilst the full CIA is not a public document, the Whakarāpopototanga o ngā Tūtohu (Summary of Recommendations) for proposed flood mitigation options 1C and 1D is available on the Cultural Impact Assessment Resources Page of this website.
Please note, the Project team recognise mātauranga Māori exists in many places and forms and remain very open to receiving further cultural input.
