THE RIVER MOUTH GROYNE
For many in our community, what happens at the river mouth is just as important as the Option 1C+ floodway works upstream at North Clyde.
We are now investigating the Wairoa River mouth groyne – what it is, how it works, and how it fits within a broader, more holistic approach to managing flood risk across Wairoa.
We are working through the concept stage and exploring potential funding options for construction.
Part of this concept stage includes some site investigative work, so you may see survey crews or divers near Pilot Hill – they’re working to gather the information we need to further design and help build a picture of the geology, and the ecological and cultural environment of the river mouth.
One project, a holistic approach
The Wairoa Flood Mitigation Project has been underway since the devastating Cyclone Gabrielle flooding of February 2023, guided throughout by the shared kaupapa of the Tripartite partners – Wairoa District Council, Tātau Tātau o Te Wairoa Trust and Hawke's Bay Regional Council – working alongside the community, mana whenua and technical experts.
As that work has progressed, it has become clear that protecting Wairoa is not about a single structure in a single place. It is about a holistic approach to flood plain management that looks at the whole lower Wairoa River from the awa upstream through to where it meets the sea.
The pieces of that bigger picture include:
The river mouth groyne is a separate piece of work from the North Clyde floodway, but it is part of this same bigger picture, with the same shared kaupapa. Together, these workstreams seek to provide the best possible flood protection across the whole catchment.
How the groyne idea came about
The possibility of a structure at the river mouth grew out of the community's own kōrero. Through the engagement that began in 2023, and in conversations since, people told us clearly that what happens at the river mouth needed to be considered alongside the North Clyde works.
In response, alongside refining Option 1C+, the project team developed concepts and early cost estimates for additional flood mitigation, including a training groyne concept, with the aim of assisting the river in forming and maintaining an opening to the sea. This is the concept we are now investigating further.
We are now investigating the Wairoa River mouth groyne – what it is, how it works, and how it fits within a broader, more holistic approach to managing flood risk across Wairoa.
We are working through the concept stage and exploring potential funding options for construction.
Part of this concept stage includes some site investigative work, so you may see survey crews or divers near Pilot Hill – they’re working to gather the information we need to further design and help build a picture of the geology, and the ecological and cultural environment of the river mouth.
One project, a holistic approach
The Wairoa Flood Mitigation Project has been underway since the devastating Cyclone Gabrielle flooding of February 2023, guided throughout by the shared kaupapa of the Tripartite partners – Wairoa District Council, Tātau Tātau o Te Wairoa Trust and Hawke's Bay Regional Council – working alongside the community, mana whenua and technical experts.
As that work has progressed, it has become clear that protecting Wairoa is not about a single structure in a single place. It is about a holistic approach to flood plain management that looks at the whole lower Wairoa River from the awa upstream through to where it meets the sea.
The pieces of that bigger picture include:
- the North Clyde floodway (Option 1C+), where enabling works are now underway
- operational management of the Wairoa River mouth and bar, which is in place now
- a possible structural solution at the river mouth – the training groyne, which is under investigation
- investigation into the benefits of upper catchment management of erosion and sediment through native planting, and
- resilience upgrades to the rainfall, water level, and climate telemetry network that provides Regional Council and the public with early warnings for severe weather events.
The river mouth groyne is a separate piece of work from the North Clyde floodway, but it is part of this same bigger picture, with the same shared kaupapa. Together, these workstreams seek to provide the best possible flood protection across the whole catchment.
How the groyne idea came about
The possibility of a structure at the river mouth grew out of the community's own kōrero. Through the engagement that began in 2023, and in conversations since, people told us clearly that what happens at the river mouth needed to be considered alongside the North Clyde works.
In response, alongside refining Option 1C+, the project team developed concepts and early cost estimates for additional flood mitigation, including a training groyne concept, with the aim of assisting the river in forming and maintaining an opening to the sea. This is the concept we are now investigating further.
