by Gary Hamilton-Irvine 

A Government review into Wairoa’s latest floods has labelled a decision not to begin opening the Wairoa River bar earlier as “surprising”, given the information Hawke’s Bay Regional Council had available to it. 

It also hit out at the council’s 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’s Bay, after the Wairoa River overflowed. 

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

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

That included a “rapid” Government review led by former Police Commissioner Mike Bush, and an independent review commissioned by Hawke’s Bay Regional Council. 

“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,” the review read. 

“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.” 

Bush noted Wairoa is a remote, vulnerable community and was already grieving the damage wrought by Cyclone Gabrielle when June’s 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, “making it hard for the river to flush to the sea”. 

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 “moderate” rainfall forecast ahead of time by MetService, which the Hawke’s Bay Regional Council (HBRC) used to help make decisions. 

The Wairoa River and bar is managed by the HBRC. 

‘Proved far too late’ 

Bush found 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.  

“This proved far too late to move the required machinery and undertake the work prior to peak rainfall and poor sea conditions.” 

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

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

“Given 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,” the review read, referring to feedback from the HBRC. 

“Accordingly, HBRC’s 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.” 

The regional council’s 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’s review said it a “matter of concern” that people in Wairoa had not been given more warning of the potential for flooding, given the only way to prevent it wasn’t likely to be successful. 

“In 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,” it said. 

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

Recommendations 

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

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

“An 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. A long-term contract for both regular maintenance and per-event work must be in place with expert contractors.” 

The review found the 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. 

“Many 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.” 

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

“We 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,” the review said. 

“Making this change would also require amendments to legislation. 

“However, 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.” 

Timeline of the floods 

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 moved 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. 

“Working 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. 

“The 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. 

“A 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. 

“We will also carry out bathymetric [river depth] surveys, when conditions allow.” 

Ministers respond 

Environment Minister Penny Simmonds said the review highlighted “shortcomings around planning and management” of the river mouth and bar. 

“[It also recognises] the need for greater engagement from the Hawke’s Bay Regional Council with the Wairoa District Council and community on emergency preparedness. 

“The report clearly states that now is the time to act decisively and with urgency.” 

Local Government Minister Simeon Brown said the review’s recommendations would help the new 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.