Frustration over West Coast bridge collapse as more rain on way

Thursday, 28 March 2019

The NZ Transport Agency (NZTA) says there is no evidence to support claims a lack of maintenance caused a state highway bridge to collapse during this week's storm on the West Coast.

The Waiho River bridge on State Highway 6 near Franz Josef was destroyed when heavy rain flooded the river on Tuesday. The wild weather also flooded highways and two homes on Wednesday, and caused the death of Gloria Reardon-Hirst, 66, when she was swept away in surging floodwaters in the Arahura Valley.

NZTA system manager Pete Connors said it was unlikely anything could have been done to save the Waiho bridge given the 'massive force' of the swollen river, the huge amount of rock pounding the bridge's piers, and the amount of debris that had built up over the day. 

The bridge's river protection system had undergone maintenance and extra rock work just two weeks earlier. 

**READ MORE:

* Live: Storm dumps rain on north, leaves destruction in south

* Coasters on clean-up duty have till Sunday before the rain returns

* Woman named after being killed in West Coast floodwaters as scale of destruction unfolds**

Claims a temporary stopbank directed the river channel towards the north bank were not correct, Connors said. 

The temporary stopbank, which was used to access the river's groynes for rock wall repairs, had eroded as it was designed to do before the flood peaked on Tuesday. 

Connors said the river bed had been building up in the centre over recent months, which was 'beyond anyone's ability to alter'.

It appeared a large boulder hit the bridge's northernmost pier, which was in the river, causing it to buckle and collapsing the main northern span. Other bridge spans were then pulled downstream off their pier foundations. 

Connors said NZTA was 'fully committed' to replacing the bailey bridge and hoped to be able to reopen the road within seven to 10 days.

WARNINGS OVER BRIDGE RISK IGNORED

Westland mayor Bruce Smith said a meeting was held to discuss the community's concerns in Franz Josef with the West Coast Regional Council and NZTA on Monday – just a day before the storm hit.

'I'm aware of the significant level of frustration that was in place leading up to this event and there will be clearly some questions asked of the regional council and NZTA.' 

Franz Josef businessman Logan Skinner said also he emailed the regional council and NZTA two days before the bridge collapsed.

He told them he had heard rocks were missing below the bridge and the river was pointing towards the bridge's north abutment, which could be problematic.

'It was not critical now but may be an issue if we get good rain,' Skinner said in the email. Rain destroyed the bridge two days later.

NZTA network manager Colin Hey replied on Monday saying 'all should be fine, hopefully for a while'.

Skinner said locals knew the design of the flood protection that was in place 'wasn't right'.

'Millions have been lost in the economy here. Our reputation has been badly damaged.

'Landslips can't be avoided but this didn't need to happen – there was enough warning for the bridge for a long time.' 

Skinner said visitors were cancelling bookings for as far away as late April.

'[It] is disappointing because we'll have a bridge up and functioning again [by then], but people don't know and they make plans now … that's had a big impact on accommodation, restaurants and tourists.'

Local residents and businesses had been asking for a proper plan for managing the river 'for years'.

'We've banged our heads against the proverbial brick wall for years. We don't have a lot of luck with the regional council.

'There's a huge amount of money wasted on reports, but nothing ever comes of the reports.'

West Coast Regional Council chairman Andrew Robb said the long term management of the river was a 'huge' discussion.

'It's a pretty tricky river to even try and attempt to manage.'

Robb said the river had risen about eight meters in the last 20 or 30 years. 

'There's a huge amount of gravel, the information we have from engineers is the bed is degrading and lifting about 200mm a year.'

Robb did not attend the meeting on Monday but said he was told the parties 'worked out a way forward'. 

'The general feeling of the meeting is, was there a good way forward? Now the flood happened, there are a lot of people that will be affected and emotions will be high and there will be things said.

'But I think we need to take a step back, take a look at what's happened, work with everyone to get things up and running again.' 

The most recent report prepared for the council by Tonkin + Taylor and Ernest and Young in October 2017 said the Waiho River was among the 'most difficult' New Zealand rivers to manage.

'It is likely that in 30 years, or sooner as a result of significant storm events, the bed of the river will be equal to, or higher than, the level of Franz Josef township if there is no further intervention,' the report said.

University of Canterbury Professor Tim Davies said it was the first time the bridge had been badly damaged since December 1995, when 15 metres of the northern approach was washed out due to flooding. 

The bed of the Waiho River had risen by about 6m at the bridge since 1982, worsened by the stopbanks that had been on both sides of the river since the 1970s to keep the river in its pre-1980s bed. 

'The Waiho is the only major West Coast river to experience this problem; but it only takes one bridge failure to halt all West Coast tourist traffic.'

A long-term solution was needed urgently to protect the Franz Josef community and its tourism industry, Davies said. 

CALL FOR TOURISTS TO KEEP COMING

Westland remained in a state of emergency on Thursday, and authorities would review it at 9am on Friday.

Smith said the community was starting to clean up and felt 'very much under control'. 

'We've got various bridges and side roads that are out, that's the focus at the present time. The clean up will take place very very quickly, it's not going to be months.'

The West Coast Emergency Management Group said all travellers who were delayed in Fox Glacier, Haast and Franz Josef had been able to make their way out of the affected areas since the highway reopened north and south of the river on Wednesday. 

It urged motorists to continue taking extra care as there was still water and debris on the road in places. 

Workers were cleaning up and repairing affected areas, but it was possible there could be more slips due to the intensity of the rainfall over the last few days.

Properties in Haast and inland from Hokitika were still experiencing power disruptions.

Any Westland residents concerned about flooded properties were advised to contact the district council to arrange an assessment. 

Glacier Country Tourism Group chairman Ashley Cassin said the loss of the Waiho bridge was a 'significant issue', but he urged people to still visit the area.

'The Franz Josef township gets over 5 metres of rain a year – we live in a rain forest. It's just that we've had 10 to 15 per cent of our annual rainfall in a really short window.' 

He did not believe the forecast storm at the start of next week would have 'quite the ferocity' of this week's storm. 

Helicopters were up in the sky on Thursday but the aerodrome where Air Safaris and Skydive Franz Josef operated from was still shut after being flooded. 

Meanwhile, State Highway 6 was open between Haast and Makarora on Thursday, but a slip had reduced a section of the road to one lane.

State Highway 6 was also down to one lane in sections between Hokitika and Franz Josef. 

State Highway 73 was closed between Arthur's Pass and Jacksons due to water flowing over the bridge at Kellys Creek. It reopened about 2pm on Thursday.

The West Coast Wilderness Trail remained closed between Cowboy Paradise and Lake Kaniere as the approaches to several bridges were washed out and the road had scouring and washouts. 

The affected part of the cycle trail was expected to be closed for several days. 

Mahinapua Creek was also still inundated with water and impassable. 

The trail was open between Kawhaka and Cowboy Paradise, but riders were warned to expect some scouring and washouts. 

RAIN, GALES FORECAST TO COME

MetService meteorologist Micky Malivuk said another – although shorter lived – burst of heavy rain was forecast to start overnight Sunday. That event could also bring severe gales in the east.

While total rainfall amounts would not be high, there was a chance of some intense hourly rates on the West Coast from Sunday into early Monday. A few more days of settled weather were then expected.

MetService had also forecast a chance of severe gales on Sunday or Monday for the southwest of the South Island, inland Otago and the Canterbury high country, then Marlborough, Wellington and southern Wairarapa.

'This situation might be windier than the one we just had,' Malivuk said. 'It's a low tightening, so there might be some strong winds close to the low on the West Coast.' The strongest winds would still probably be in Canterbury, Marlborough and Wellington.

Since the next bout of rough weather was still a few days away, the forecast still needed to be fine-tuned, Malivuk said.

The slow-moving rainband that crept up the West Coast this week brought astonishing amounts of rain to locations tucked in close to the western slopes of the main divide.

New Zealand's wettest monitored location, Cropp River at Waterfall, set a national record during the deluge.

The particularly pluvial location, about 975m up and about 40 kilometres inland south from Hokitika, recorded 1086 millimetres in 48 hours. The National Institute of Water and Atmospheric Research (Niwa) said this was New Zealand's highest 48-hour total since records began there in 1982.

Cropp River's previous highest two-day fall was 1062mm in 2013.

Niwa climate scientist Nava Fedaeff said other records were challenged but not quite broken.

Hokitika recorded 173mm of rain in 24 hours, making it the second wettest March day since records began in 1866. Milford Sound had 401mm of rain in a day, its second wettest day in March since records began in 1929, and Mt Cook recorded a daily total of 291mm of rain, again the second wettest March day since records started there in 1928.