Controversial floodwall ‘may never stop leaking’

Nicole Mathewson Reporter from The Press

By local democracy reporter Brendon McMahon:

Transfer of a controversial Franz Josef flood bank into West Coast Regional Council ownership remains to be seen as engineers assess the extent of its leaks.

The Havill Wall was controversially authorised by former Westland mayor Bruce Smith and his close ally, former councillor Durham Havill, following an April 2016 storm.

The event saw the Waiho (Waiau) River overtop an existing stopbank at the northern entrance to Franz Josef and wipe out the sewage treatment site.

It also ruined the now abandoned Scenic Group Franz Josef Mueller Wing hotel complex.

Transfer of the wall's ownership to the regional council is included in its 2024-34 long-term plan (LTP) as it moves to complete a $12.5 million stop bank improvement scheme in the area.

But during the recent formal LTP hearing, council chief executive Darryl Lew said the underlying engineering integrity of the Havill Wall still needs to be better understood.

Councillor Peter Ewen said he still felt uneasy about the Havill Wall and wanted to see how it coped with "a real southerly storm".

Councillor Andy Campbell, chair of the Franz Josef Joint Rating District, said the wall as it was, "may never stop leaking".

Lew said the regional council knew full well of the Havill Wall's "seepage" issue.

But at this stage council needed to fully understand to what extent that seepage compromised the structure's flood protection value.

Lew said all flood banks administered by council across the region to some extent "have seepage" and were never entirely "impervious flood barriers," he said.

It was if the degree of seepage was "acceptable to its viability", with that aspect currently under engineering investigation.

Lew said if the seepage was assessed as acceptable without compromising the protection value of the wall, "then that's fine".

If not, then it would not be acceptable to take on ownership.

Lew also noted the Government money for the north bank scheme had included future mitigation of the Havill Wall.

Ewen asked if the ownership transfer idea also extended to an emergency extension built at the end of the wall by the district council, following the January 2024 weather event.

The district council built the small extension amidst fears that, with the Waiho River having swung north into the neighbouring Tatare Stream, it might eventually take out the Franz Josef sewage ponds on the same side.

Lew said what the district council had done was "really an isolated" piece of work and the regional council did not intend to take it on.

The Havill Wall was controversially thrown up without regional council consent.

In 2017 Westland District got a grilling from the Office of the Auditor General over its actions, and the wall subsequently got retrospective consent.

The regional council has already undertaken work on the Havill Wall under its $12m Waiho northern bank protection scheme - which aims to increase resilience for the tourist hotspot of Franz Josef.