Longer timeframe for new Bailey bridge across Waiho River, South Westland


The NZ Transport Agency has revised its timeframe to reconnect State Highway 6 in South Westland at the Waiho River, says Transport Agency System Manager Pete Connors.

SH6 Waiho River bursting stopbanks - 30 March 2019

SH6 at Canavans: the Waiho overtopping the stopbank on the south side, downstream of the bridge site earlier this week.

The Bailey bridge over the Waiho was wiped out by a flood and high velocity, rock-filled river flows on Tuesday afternoon. Originally a seven-to-ten-day timeframe was estimated for the bridge to be replaced and operational.

“The new timeframe of 14 to 17 days could take us through to Friday, 12 April, ahead of the school holidays and Easter. Given there is more wet weather forecast for Sunday night through Monday 1 April, combined with a more refined work programme, we have revised our estimates so people have realistic timeframes in order to plan their movements and journeys around the South Island.

“We all understand what a critical link the Waiho Bridge is for the West Coast, and we are making every endeavour to shorten the timeframe if at all possible. If there is any change to this programme, we will advise people immediately.”

Bridge will take all vehicles once completed

One positive aspect of the longer timeframe is that once in place, the new single lane bridge will take all vehicles categorised as Class 1, including heavier trucks, not just cars and buses as originally planned, Mr Connors says.

South side of Waiho concerns

Temporary repair works to the Waiho’s south side stopbank have been underway this week in anticipation of 150 mm of rain forecast for Sunday and Monday.

Because of the build-up of material on the river bed from the flood, it could take two to three months for this stopbank to be reinstated to its previous level of protection, Mr Connors says.

The stopbank protects SH6 which runs next to it as well as adjoining farm land.  (See photo below.)

Progress to date

  • The Transport Agency quickly mobilised plant, crews and materials from around the country with several truckloads of componentry making their way through the Haast Pass to the south side of the Waiho in the past three days and this weekend.
  • Complex pier and foundation design is nearing completion.
  • The method for demobilising and erecting the new bridge has been finalised.
  • Truckloads of rock and earth have been moved and continue to be moved this weekend.

Coming up

Crews are constructing a rock-lined guidebank to allow pile-driving at the northern abutment (where the bridge meets the bank) on Wednesday/ mid this week.

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