Friday, March 29, 2024

When the wind blows

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Research after the September 2013 Canterbury high winds has shown farmers need to have a plan ready for when stormy weather hits to minimise damage to irrigators.
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The joint study by FMG and Lincoln University followed more than 260 claims lodged after the storm with the insurance company, at a cost of about $7 million.

More than 100 Canterbury farmers, about 50 who had not made a claim, were interviewed as part of the research and the resulting document – the Irrigator Advice Guide – is now available at fmg.co.nz

The guide said the main ways to reduce wind damage to irrigators were pointing the irrigator downwind of the prevailing wind and creating a parking space for the irrigator for each prevailing wind direction, away from any objects which might move and crash into it.

Along the parking space farmers should install anchor points to tie the irrigator down at the base beam of each tower and mid-way across the span.

Tying the irrigator down would reduce the chance of it bouncing, which some survey respondents reported seeing before their irrigator flipped.

Straightening corner arms, which were the most expensive part of the pivot irrigator, in line with the rest of the irrigator would help stop them being damaged. They should also be tied down.

‘The research found MetService had accurately predicted the Canterbury wind storms in 2013 and most respondents to the survey said they had warning of the storm’s arrival.’

Some owners said they kept water running through the irrigator, but stopped it moving, during the storm to increase its weight.

However, the report’s authors cautioned this might have positive and negative effects on the irrigator’s stability and might cause wheels to become bogged.

As well, deflating the tyres, which some farmers in the Canterbury storm tried, had mixed results.

The research found MetService had accurately predicted the Canterbury wind storms in 2013 and most respondents to the survey said they had warning of the storm’s arrival.

However, in cases when there was little or no warning, the guide said human safety came first.

If the irrigator couldn’t be moved to be downwind, as in the case of a power outage, some sort of anchoring would be better than none, as long as it could be done safely.

Topography also affected which irrigators were damaged in the 2103 storm and which were not, with evidence of wind being funnelled down river beds. Research done as part of the study showed that pivots on 7% slopes or greater were less stable.

Windbreaks were found to be most effective if some wind was able to pass through them. Solid windbreaks created greater turbulence because of the air pressure differences on either side. Gaps in windbreaks also created wind funnels.

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