FREQUENTLY ASKED QUESTIONS (FAQ)
What is a groyne?
A groyne is a structure built out from the shore into the water. The type we are investigating for Wairoa is a training groyne, which will be located east of Pilot Hill, and designed to help guide the river into forming and holding a stable, open path to the sea.
How does it work?
The river mouth naturally shifts and can build up or close over as sand and gravel move with the tides, currents and river flows. A training groyne works with the river rather than against it, guiding the flow so the river's own energy helps keep a channel open through the bar. A more open, stable mouth helps the lower river drain more freely, particularly during high flows, which supports flood resilience over time.
Who will pay to build it?
There is no confirmed construction funding at this stage. Identifying a possible funding pathway for the groyne is one of the things still to be worked through, and no decision to build can be made until that is resolved.
Most, if not all, of the Crown's $70 million contribution for Wairoa is expected to go to the North Clyde Option 1C+ floodway.
Who will pay to maintain it?
Like any flood-protection asset, a groyne would need ongoing maintenance, and experience elsewhere shows river-mouth structures can require periodic upkeep. How any future maintenance would be managed and funded has not yet been decided – this will form part of the wider funding and decision-making process and is one of the questions the investigation phase is intended to inform.
How long will it take to construct?
It is too early to say. The groyne is at concept stage only and a construction timeframe cannot be confirmed until the design is developed, costs are better understood, and funding and approvals are in place. We will share clearer information as the work progresses.
Who will have the final say on whether it gets built or not?
As the Hawke’s Bay Regional Council is responsible for flood protection and is the consenting and acquiring authority for the project, they would ultimately need to approve any decision to build, working with the Crown Manager and the Tripartite partners. Crucially, no significant decision would be made without meaningful engagement with the community and mana whenua, and without a confirmed way to fund it.
What impact does what we do at the river mouth have on North Clyde and Option 1C+?
Option 1C+ has been designed and consented to provide flood protection for North Clyde with the current river state and it is proceeding regardless of the groyne.
However, a groyne would be beneficial to North Clyde and the wider Wairoa area along the lower reaches of the awa. A more open, stable river mouth helps the lower river flow to the sea and would be an additional, longer-term flood mitigation solution for the awa.
The river mouth and North Clyde are connected parts of one lower-river system, which is why we are managing them holistically. .
A groyne is a structure built out from the shore into the water. The type we are investigating for Wairoa is a training groyne, which will be located east of Pilot Hill, and designed to help guide the river into forming and holding a stable, open path to the sea.
How does it work?
The river mouth naturally shifts and can build up or close over as sand and gravel move with the tides, currents and river flows. A training groyne works with the river rather than against it, guiding the flow so the river's own energy helps keep a channel open through the bar. A more open, stable mouth helps the lower river drain more freely, particularly during high flows, which supports flood resilience over time.
Who will pay to build it?
There is no confirmed construction funding at this stage. Identifying a possible funding pathway for the groyne is one of the things still to be worked through, and no decision to build can be made until that is resolved.
Most, if not all, of the Crown's $70 million contribution for Wairoa is expected to go to the North Clyde Option 1C+ floodway.
Who will pay to maintain it?
Like any flood-protection asset, a groyne would need ongoing maintenance, and experience elsewhere shows river-mouth structures can require periodic upkeep. How any future maintenance would be managed and funded has not yet been decided – this will form part of the wider funding and decision-making process and is one of the questions the investigation phase is intended to inform.
How long will it take to construct?
It is too early to say. The groyne is at concept stage only and a construction timeframe cannot be confirmed until the design is developed, costs are better understood, and funding and approvals are in place. We will share clearer information as the work progresses.
Who will have the final say on whether it gets built or not?
As the Hawke’s Bay Regional Council is responsible for flood protection and is the consenting and acquiring authority for the project, they would ultimately need to approve any decision to build, working with the Crown Manager and the Tripartite partners. Crucially, no significant decision would be made without meaningful engagement with the community and mana whenua, and without a confirmed way to fund it.
What impact does what we do at the river mouth have on North Clyde and Option 1C+?
Option 1C+ has been designed and consented to provide flood protection for North Clyde with the current river state and it is proceeding regardless of the groyne.
However, a groyne would be beneficial to North Clyde and the wider Wairoa area along the lower reaches of the awa. A more open, stable river mouth helps the lower river flow to the sea and would be an additional, longer-term flood mitigation solution for the awa.
The river mouth and North Clyde are connected parts of one lower-river system, which is why we are managing them holistically. .
