Heavy machinery caught in floodwater at the Wairoa River mouth on 26 June 2024. The digger is used to open up a channel in the bar to let floodwater escape more quickly. Photo: Supplied / Siobhan Pryde
A review into the flood that devastated Wairoa in June has found Hawke's Bay Regional Council lacked a proper plan for managing the river mouth, and did not listen to locals who called for action before heavy rain was forecast.
The government commissioned the urgent review after more than 400 properties flooded when heavy rain pelted Wairoa on 26 June.
There was huge public backlash towards the Hawke's Bay Regional Council for not digging a channel to let the rising river release into the sea sooner - known as 'opening the bar'.
The review by Mike Bush of Bush International Consulting, released on Wednesday, stopped short of saying definitively whether the bar should have been opened sooner.
It noted a separate technical report commissioned by the regional council which found the flooding was caused by a combination of factors: "high rainfall, rising river level, spring tides, large waves, storm surge, as well as the position and size of the river mouth through the bar".
But the Bush review did say the council's decision not to open the bar earlier, as a precaution, was "surprising".
It highlighted key problems with the regional council's river management:
- There was no operational plan for managing the bar despite its known impact on flood risk.
- There was no ongoing formal contract with local contractors to open the bar.
- Its current "instructions document" was not clear or specific about what triggers should initiate an opening.
- The council did not have good enough relationships with local leaders, iwi and the community to aid in its decision-making
- It lacked a proactive, precautionary approach, resulting in "optimism bias" and failure to consider worst case scenarios early enough.
- It relied on Metservice forecasts - previously proven to underestimate rainfall in Wairoa - instead of NIWA's forecast which predicted higher rainfall.
Decision not to open the bar "surprising"
Local leaders and contractors had told the regional council the bar should be opened days before the rain hit, the report said.
"In the context of this event, we find it surprising that, given the current non optimal location of the bar, the forecast sea state and the weather warnings, a precautionary opening of the bar was not commissioned and attempted well in advance of the forecast rain.
"We find it even more surprising that, in a town dominated by such a significant and obvious natural hazard, the bar is not more regularly and proactively planned for and managed based on local understanding of threat levels, in addition to the available technical data."
The council told the review "no notable rainfall" was forecast for Wairoa until the day before the flood, when it attempted to open the bar, and a successful opening was unlikely given sea conditions.
"Despite HBRC's position, we consider there is clear scope for improving management of the bar.
"If anything, HBRC's position highlights the need for current approaches to change, since mitigation steps may not be able to be taken prior to any immediate threat."
Short-term solutions and recommendations
The review recommended three immediate actions:
- Establish a master contract with the local contractor, so that a new contract does not have to be formally struck every time the mouth needs opening.
- Initiate a formal programme of regular forums, with local Wairoa community leaders, including iwi, to discuss river risk management, including mouth openings.
- Work with technical experts and knowledgeable locals to develop a specific operational plan for the river, including triggers for clearing the mouth, standard operating procedures, monitoring guidelines and key performance indicators.
The operational plan was of "critical importance", it said.
The review also said central government should clarify the current legislative framework for flood management, which is confusing and currently spread across multiple pieces of legislation.
The sand bar at the Wairoa River mouth. Photo: RNZ / Samuel Rillstone
Locals felt ignored
The arrangements for taking local knowledge into account was "inadequate", the report said.
It was a strong and consistent theme in the 66-page review.
Communication from the regional council to Wairoa leaders and the community was too slow in the early stages of the flood event - leaving residents struggling to escape their homes given it was night time, and the water was already deep.
"On one Kopu Road property a householder battled to get his pregnant daughter and grandchild over the back fence in the dark."
Wairoa District Council staff and contractors told the review they regularly felt "not listened to" by senior council staff during planning for and response to flood emergencies.
"As an example, on the Friday prior to the flooding, the HBRC put the local contractors for the bar on standby but did not let Wairoa District Council staff know about this. Nor did they share their 'worst case scenario' regional forecasting in the days immediately prior to the event.
"The latter clearly showed poor potential outcomes for Wairoa."
The council did not consider knowledge from locals who "have lived with the threat of the river for generations," it said.
"Many in the Wairoa community told us that, since the centralisation of river mouth management to the HBRC team, they felt decisions were increasingly disconnected from local insights, indigenous knowledge and institutional memory around previous management practices."
Leaders and locals found HBRC staff were "patronising" and "technocratic".
"Whether or not these perceptions are accurate, the reality is that they exist and will have an impact on the relationship and, accordingly, management of flood risk."
The report did not suggest that river management be handed back to the Wairoa District Council, as it does not have the expertise, resource or legislative power.
But the regional council must improve its relationships with Wairoa leaders, including civic leaders and iwi, the report said.
Opening the bar not enough
The Hawke's Bay Regional Council also on Wednesday released findings from three independent reviews it commissioned into the flooding.
They found high rainfall, rising river levels, spring tides, storm surge and the position of the bar coincided to create a 1-in-250-year flood event.
"We heard from residents that this type of flooding had not been experienced in living memory, and this is why," said Hawke's Bay Regional Council chief executive Dr Nic Peet.
"Even if the bar could have been opened, the flooding may not of have been prevented.
"However, all four reports also indicate that there are things that HBRC can improve with regard to its management of the Wairoa River mouth."
But opening the bar could not be depended on as the only measure to manage Wairoa's flood resilience, he said.
"As sea level rises and storms become more intense, further options are needed.
"We are committed to investigating these together with Wairoa District Council, Tātau Tātau o Te Wairoa and the Crown."
What's next?
The regional council had already improved the monitoring of the river bar, and staff had been working with a local contractor to improve its condition, said Peet.
That included creating an overflow trench for the river to spill into when it rains, which also meant the bar could be opened more quickly.
A number of cameras would be installed along the river, and when conditions allowed, river depth surveys would be conducted.
"Further, we are making sure that we have a comprehensive operational plan in place for the management of the bar and are working to ensure that we have enduring and clear arrangements in place with a local contractor," Peet said.
Local government minister Simeon Brown said the Bush review's recommendations would help Crown Manager to the Hawke's Bay Regional and Wairoa District Councils, Lawrence Yule, to direct the councils in the planning and delivery of flood protection works.
The Wairoa District Council, Hawke's Bay Regional Council, and iwi entity Tātau Tātau o te Wairoa are still working out how to spend the $70 million set aside for flood protection, which currently does not exist in the town.
