Heavy deluge prompts action

By: Randall Johnston, Photography by: Ashburton District Council

Machinery operators and contractors played a major role in the immediate emergency response in North Canterbury

The Canterbury region was battered with rain over three days, causing a huge amount of damage to property, roads, and infrastructure in a ‘one-in-100 years’ rainfall and flooding event in late May-early June.

After months of hardly any rainfall in the region, the sheer amount of constant rain and run-off caused big problems well before the first 24 hours of constant rain had passed. Falls exceeding 500mm were recorded in the Canterbury High Country over the three days, as waterways breached their banks.

Severely affected districts included Kaikoura, Hurunui, Waimakariri, Selwyn, Ashburton, Timaru, Mackenzie, and Waimate.

Some areas that only get 50mm on rainfall a year got 300mm in one day alone; the resulting flooding leading to a regional state of emergency declaration and the closure of 10 State Highways.

The Ashburton River Bridge was closed, cutting off the main route to and from Christchurch and disrupting the transportation of goods, as roads, farmland, and properties in North Canterbury were inundated with floodwaters.

The vital section of State Highway 1 link shut to all vehicles on 1 June, after truck drivers noticed a concerning slump on the bridge. Thorough testing was undertaken and it reopened to all traffic, including heavy vehicles on 3 June.

The supply chain was seriously disrupted south and north of Ashburton, urging renewed calls for a new alternative route and second bridge capable of accommodating large volumes of heavy haulage.

"The bridge closure was needed to carry out ongoing survey monitoring of the structure following the flood-related settlement," Waka Kotahi NZ Transport Agency system manager Pete Connors explains.

A number of Ashburton area residents, contractors, and road workers spent the following long weekend repairing flood damage, at which point the major repairs had still really only just begun.

Combined Christchurch New Zealand Response Teams also worked over the Queen’s Birthday weekend providing flood/river monitoring, ground evacuations, and working cordons. They also delivered food, water, and medications to residents in need, as well as supporting Ashburton District Council Civil Defence emergency operations.

The threat to life was real; several people had to be rescued and livestock, fencing, and machinery was lost, but early weather warnings did help to give many landowners time to shift their assets to higher ground.

The clean-up is likely to take months, with a number of roads in need of repair and areas of private land needing to be cleared of debris.

Machinery operators and contractors played a major role in the immediate emergency response in North Canterbury, and farmers who weren’t frantically shoring up the situation on their own property, came to each other’s aid.

The long weekend following the torrential rains was spent repairing flood damage

A worker from Curle Contracting put his excavator to work to dig out and clear a blocked waterway in Springfield, which likely prevented a large swathe of the township from flooding on 31 May.

Earth was also moved to create stopbanks to protect houses after a waterway in Springfield broke its banks.

Local contractors also widened the water race, which saved at least one home from flooding.

Greendale and Hororata in the Selwyn district were also particularly hard hit.

Darfield resident Tim Gillanders, whose 800-hectare crop farm was inundated as the Hawkins River, which is normally bone dry, became a raging torrent and was one of those affected.

"We got around 400mm over those three days, and it flooded between 60 and 80 hectares of our land, but thankfully, damage to the wheat crops is minimal. Our family has farmed this land since 1865 and even my father Andrew has never seen anything like it.

"My uncle to had to rip out a gorse hedge with his John Deere front-end loader to alleviate the flooding over Greendale road, and a man was winched to safety by a helicopter from his Ford Ranger, which was swept down the Hawkins River as he attempted to cross the ford (on the evening of 31 May)."

Between 60 and 80ha of Darfield resident Tim Gillanders’ property was flooded

It took five full days for the river to subside and Tim says he is hoping it doesn’t happen again for another 100 years!

The debris deposited over a wide area was huge and the clean-up for many is massive and will take a very long time to complete. It’s not the sort of thing that many will be able to do themselves unassisted and the contractors in these areas are now flat out.

It will be hard to find an excavator or dozer not seeing heavy use in Canterbury, as the clean-up is in full swing. More on that in the next edition as we speak with contractors on how the big clean-up is progressing.

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