Construction has officially started on the long-awaited second bridge across the Ashburton River, with diggers turning ceremonial sods at a reserve near Chalmers Avenue on Friday afternoon. The almost 150 million dollar crossing has been talked about in mid Canterbury for two decades, and Ashburton mayor Liz McMillan said it took eight terms of council before the project finally got off the drawing board.
The new bridge will run roughly 2.5 kilometres including its connection road, linking Chalmers Avenue on the northern side of the river with Carters Terrace on the southern side near Tinwald. It is expected to be open to traffic by the end of 2027, with the build cost sitting between 134 and 144 million dollars according to RNZ.
The need for a second crossing has been blindingly obvious to anyone who has driven State Highway 1 through mid Canterbury for any length of time. About 24,000 vehicles cross the existing bridge each day, a mix of commuters heading between Tinwald and Ashburton, freight trucks moving up and down the South Island, tourists chasing the Alps, and farmers shifting stock and machinery. When the single bridge fails, the whole island feels it.
That fragility was exposed brutally in 2021, when floodwaters and debris damaged the State Highway 1 bridge and forced its temporary closure. Supply chains down the lower South Island came close to collapse, and the only alternative route between Christchurch and the south involved a 13 hour inland diversion. The bridge was knocked out again in 2023 when another severe weather event tore through the catchment, leaving locals reliving the same nightmare and reinforcing every argument for a second route.
Transport Minister Chris Bishop and South Island minister James Meager were due to attend the sod-turning ceremony but missed it after their flight to mid Canterbury was cancelled. Bishop, speaking afterwards, said the bridge would be a game changer for residents and for the wider regional economy.
“A second crossing over the Ashburton River is going to be a game changer for residents moving around and through the mid Canterbury town. It will also be important for economic growth as traffic volumes ease for commuters, tourists and freight operators on the existing crossing via State Highway 1,” Bishop said in comments released by his office. He noted the project was being delivered as one of the government’s Roads of Regional Significance, in partnership between NZ Transport Agency and the Ashburton District Council.
Meager, who took up the South Island portfolio after the 2023 election, framed the build as a resilience project rather than just a convenience upgrade. “About 24,000 vehicles use the current bridge daily. This is a key route for ensuring our people and goods can get up and down the South Island and needs to be future proofed. Having a second crossing connecting Tinwald to Ashburton provides a critical back-up and lifeline in the event of crashes, emergencies or severe weather events that may impact SH1, which has occurred in recent years,” he said.
Mayor McMillan, who has watched the project crawl through council agendas since the first feasibility survey was commissioned in 2006, was visibly emotional at the ceremony. “Eight terms of council to get this far, 2006 the first survey was done, so I’m really, really excited,” she said. McMillan added that the loss of productivity from people sitting in queues at the existing crossing had been a real handbrake on the town, and that getting the second bridge underway felt like a long-overdue acknowledgement of how heavily Ashburton was carrying traffic for the rest of the South Island.
NZ Transport Agency infrastructure delivery regional manager Sean Walsh said the engineering would also lift the resilience of the corridor. The main bridge will be 330 metres long, built as 11 spans of 30 metres each, supported on piers that sit on very deep pile foundations. The deck will also be set higher than the existing State Highway 1 bridge to give it more clearance above flood debris. “This is absolutely a win-win. It’s a win for the district council in Ashburton, they get an awesome connection between the main town of Ashburton and Tinwald. But it’s also a win for Waka Kotahi because we have a great piece of resilience here if the main bridge goes down as it has in the past,” Walsh said.
Once open, the new route is expected to soak up more than a fifth of the traffic now using the old crossing, easing congestion at peak times and giving the highway network a built-in backup if the State Highway 1 bridge is ever lost again. The build will also include two general traffic lanes, cycle lanes and a shared path, in a deliberate attempt to give the town a piece of infrastructure that works for more than just cars and trucks. Background context on the long planning saga and the wider bypass debate is captured in RNZ’s earlier coverage of the 15 year transport saga.
For mid Canterbury, the diggers turning over the topsoil at Chalmers Avenue this week are the first physical sign that two decades of arguing, lobbying and waiting are finally being repaid.
What do you make of the second Ashburton bridge finally getting underway after twenty years of talk? Are there other South Island chokepoints that deserve the same treatment? Leave a comment below and join the conversation.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job π
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