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Wairoa flood review hits out at 'surprising' decision making, lack of warning for residents

Author
Gary Hamilton-Irvine,
Publish Date
Wed, 11 Sep 2024, 11:15am
The Hawke's Bay town of Wairoa pictured from the air 10 days after the devastating flooding. Photo / Paul Taylor
The Hawke's Bay town of Wairoa pictured from the air 10 days after the devastating flooding. Photo / Paul Taylor

Wairoa flood review hits out at 'surprising' decision making, lack of warning for residents

Author
Gary Hamilton-Irvine,
Publish Date
Wed, 11 Sep 2024, 11:15am

A Government review into Wairoa鈥檚 latest floods has labelled a decision not to begin opening the Wairoa River bar earlier as 鈥渟urprising鈥, given the information Hawke鈥檚 Bay Regional Council had available to it.

It also hit out at the council鈥檚 culture, its communication with Wairoa officials and locals, its tendency to be overly optimistic, and the lack of warning given to those in the firing line of the potential for flooding in June.

However, the review did not go as far as stating an earlier opening of the bar would have avoided the floods that swamped the lower part of the township.

About 127 homes were flooded (and hundreds more affected) by the June 26 floods which tore through the lower part of Wairoa township, in northern Hawke鈥檚 Bay, after the Wairoa River overflowed.

Long-term residents say they have听never experienced flooding to that extent in that part of town听before, and听some residents feared for their children鈥檚 lives during the floods.

Fortunately, no-one was physically injured in the emergency.

Two reviews landed on Wednesday, both probing the floods and making recommendations for better management of the Wairoa River.

That included a 鈥渞apid鈥 Government review led by former Police Commissioner Mike Bush, and an independent review commissioned by Hawke鈥檚 Bay Regional Council.

鈥淚n 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,鈥 Bush鈥檚 Government-ordered review read.

The flooding to the Wairoa township. Photo / SuppliedThe flooding to the Wairoa township. Photo / Supplied

鈥淲e 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.鈥

Bush noted Wairoa is a remote, vulnerable community and was already grieving the damage wrought by听Cyclone Gabrielle听when June鈥檚 weather event arrived.

Combination of factors

The Government review found three clear factors led to the flooding.

That included the placement of the river mouth which had formed toward the south of the bar, prior to the flood event, 鈥渕aking it hard for the river to flush to the sea鈥.

The other two factors included unusually high seas, which saw large waves crash over the bar into the river and lagoon prior to the floods, and 鈥渕oderate鈥 rainfall forecast ahead of time by MetService, which the Hawke鈥檚 Bay Regional Council (HBRC) used to help make decisions.

The Wairoa River and bar is managed by HBRC.

鈥楶roved far too late鈥

Bush found that in June, local contractor Pryde Contracting was not formally mobilised until late on Monday June 24 for Tuesday prework and a potential opening of the river mouth on Wednesday June 26 - the day of the flood.

鈥淭his proved far too late to move the required machinery and undertake the work prior to peak rainfall and poor sea conditions.鈥

The state of the bar after the floods. Photo / SuppliedThe state of the bar after the floods. Photo / Supplied

It takes well over two days to make a new opening in the bar with machinery, Pryde has previously told听Hawke鈥檚 Bay Today.

However,听no notable rainfall was forecast for Wairoa until Monday June 24, when the works were instigated, which was a key factor for HBRC to initiate an opening.

鈥淕iven the forecast rainfall was minimal and the sea state was forecast to be significant at the same time ... the factors for a successful opening were not anticipated to align,鈥 the review read, referring to feedback from HBRC.

鈥淎ccordingly, HBRC鈥檚 position is that the approach of attempting an opening was precautionary in the circumstances, as the prospect of a successful opening was marginal at best.鈥

The regional council鈥檚 independent review noted that even if a new opening had been made in a better location on the bar earlier, there was no guarantee it would have worked or remained in place.

Public warning

Bush鈥檚 review said it a 鈥渕atter of concern鈥 that people in Wairoa had not been given more warning of the potential for flooding, given the only way to prevent it wasn鈥檛 likely to be successful.

鈥淚n view of the fact that Wairoa is a town wholly reliant on a single method of risk mitigation for river mouth driven flooding (mechanical mouth opening) and that the relevant managers knew that method had not had time to be brought to bear, we find these decisions not to act in a precautionary manner on at least the day prior to the event a matter of concern,鈥 the Government review noted.

Bush noted that in many cases, officials in the lead-up had an 鈥渙ptimism bias鈥, and did not fully take into account worst-case scenarios.

Recommendations

The Government review provided a number of recommendations, including a new management plan.

鈥淭he way forward seems clear to us and was echoed by most of those we interviewed.

The Wairoa Bar, as seen on June 29, with new river mouth openings blasted out naturally.The Wairoa Bar, as seen on June 29, with new river mouth openings blasted out naturally.

鈥淎n Operational Management Plan for the Wairoa River and bar is essential to support regionally co-ordinated and locally delivered emergency preparedness, risk reduction and response.

鈥淎 long-term contract for both regular maintenance and per-event work must be in place with expert contractors.鈥

The review found HBRC uses a range of information to make a decision on river mouth openings.

However, it does not have cameras at the river mouth (though these are being planned), river level gauges near the mouth, or satellite tracking of river mouth position and movement of the bar.

鈥淢any in the Wairoa community told us that, since the centralisation of river mouth management to the HBRC team [in Napier], they felt decisions were increasingly disconnected from local insights, indigenous knowledge and institutional memory around previous management practices.鈥

It also recommended a change in the culture of the way HBRC deals with and communicates with the Wairoa community to bring trust back.

鈥淲e do not suggest, as some Wairoa respondents did, that this should entail reversion of control to or full delegation of authority for monitoring and opening to Wairoa District Council. We do not consider that body to hold the expertise, resources or powers to hold that responsibility. Making this change would also require amendments to legislation.

鈥淗owever, core to any programme of future improvement are better relationships and deeper shared understandings between HBRC staff and leaders and Wairoa local leaders, including civic leaders and iwi.鈥

Timeline of the floods

Local contractor Pryde Contracting was put on standby by the regional council on Friday June 21 (five days before the floods), but did not get the go-ahead from the regional council until the afternoon of Monday June 24 to attempt a new opening in the bar (to help avoid the floods).

Pryde mobilised machinery to the site (which is hard to access) that Monday afternoon and began work on the Tuesday, working until nightfall.

The river flooded the town on the Wednesday morning (June 26).

Changes made to date

HBRC chief executive Nic Peet said steps had been taken to improve monitoring of the river bar, and council staff had been working with a local contractor to improve the condition of the river bar.

鈥淲orking with a local contractor, we have lowered the existing beach crest and created an overflow trench in the Wairoa Bar, 500m to the east of Pilot Hill.

鈥淭he trench is to allow the river to overflow the bar in a rainfall event and also allows a new opening to be completed more quickly, when conditions allow.

鈥淎 number of cameras will be installed along key points on the river, and we have been working with WDC staff on the locations of these.

鈥淲e will also carry out bathymetric [river depth] surveys, when conditions allow.鈥

Ministers respond

Environment Minister Penny Simmonds said the review highlighted 鈥渟hortcomings around planning and management鈥 of the river mouth and bar.

鈥淸It also recognises] the need for greater engagement from the Hawke鈥檚 Bay Regional Council with the Wairoa District Council and community on emergency preparedness.

鈥淭he report clearly states that now is the time to act decisively and with urgency.

鈥淭o mitigate against similar future events, the report recommends the Hawke鈥檚 Bay Regional Council partner with the Wairoa Council and community to develop a Wairoa River Bar Operational Plan.鈥

Local Government Minister Simeon Brown said the review鈥檚 recommendations would help the听new Crown Manager听to the Hawke鈥檚 Bay Regional and Wairoa District councils, Lawrence Yule, to direct the councils in the planning and delivery of flood protection works.

鈥淭his plan will detail monitoring actions, identify trigger thresholds for action to mitigate and manage risk, as well as outlining communication protocols,鈥 Brown said.

Gary Hamilton-Irvine is a Hawke鈥檚 Bay-based reporter who covers a range of news topics including business, councils, breaking news and cyclone recovery. He formerly worked at 九一星空无限 Corp Australia.

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