Rivers rising rapidly as Southland finally gets rain

Thursday, 1 February 2018

Emergency Management Southland boss Angus McKay, Southland District Mayor Gary Tong and Environment Southland chairman Nicol Horrell track the rainfall across the region at the emergency co-ordination centre in Invercargill on Thursday.

Heavy rainfall in Southland has resulted in rapidly rising rivers, the closure of a school, surface flooding, trampers being confined to their huts and a warning to motorists to stay off the roads unless absolutely necessary.

The Environment Southland flood warning system was activated on Thursday due to rapidly rising rivers after rainfall drenched the previously parched Southland landscape.

Flooding in farmland near Piano Flat, Southland.

Rivers continued to rise Thursday night and were expected to peak on Friday.

After a lengthy dry spell which culminated in Southland being declared a drought area on Tuesday, the region experienced a sustained period of rain which began late Wednesday and was predicted to continue until 9pm Thursday.

The Waikaia River as at 5pm on Thursday, February 1.

Emergency Management Southland manager Angus McKay, at the floodbanks beside the Waihopai River in north Invercargill, says the Southland public needs to be alert to possible flooding danger in the region on Thursday and Friday.

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It's finally raining in Southland - Stead Street surface water in Invercargill

Farmers were rejoicing as rain hit their dry paddocks, but the rivers continued to rise on Thursday night and Emergency Management Southland warned Southlanders to stay clear of low lying areas along the Waikaia River, 'from Piano Flat downwards'.

The Waikaia River was rising by 1 metre an hour at the Piano Flat monitoring point late Thursday afternoon.

Annabelle Shepherd, 2, is all smiles in the rain in the garden in Wallacetown.

Waikaia School was closed because of surface flooding and roads were scheduled to be closed around Waikaia because of flooding on Thursday night.

Southern police warned motorists to avoid all non-essential travel and take extreme care.

Farmers have finally seen substantial rain in Southland - water lies in a paddock at Waikaia in northern Southland on Thursday.

Emergency Management Southland boss Angus McKay said the heaviest rainfall in the region was in the north-west of Southland, with about 50mm to 90mm falling by early evening Thursday.

Modelling suggested there would be another 10mm to 20mm by midnight, he said.

Between 20mm and 50mm had fallen over the rest of Southland by early evening on Thursday.

In most areas of Southland water was 'going to ground well', so there were no major concerns around the Aparima, Upper Oreti and Mataura Rivers.

The king tide resulted in surface flooding on Stead Street, Invercargill and in the southbound lane on State Highway 1, at Ocean Beach, Bluff, with the water crossing the road, Bluff community Board chairman Ray Fife said.

McKay said the intensity of the rain had been less than expected but the rivers were rising fast on Thursday afternoon, hence the flood warning system being activated.

Emergency Management Southland spokeswoman Louise Pagan said the flood warning system had been activated so the public was aware of how fast the waters were rising.

There had been some surface flooding in towns, including Gore.

'Trampers have been told to stay in the huts on the Fiordland tracks,' McKay said.

Pagan said Fiordland trampers were commonly asked to stay in their huts during heavy rain so authorities knew where they were.

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Emergency Management Southland, which set up a flood response team at its headquarters in Invercargill, monitored the rainfall and river levels throughout the day and into Thursday night.

Among those monitoring the situation at the co-ordination centre were police, with inspector Mike Bowman saying their role was to assist with the planning and make sure contingencies were in place to deal with any flooding and potential evacuations that may be needed.

McKay again reiterated on Thursday that floodbank protection in Invercargill would ensure no repeats of the 1984 flooding disaster in the city.

A Fire and Emergency New Zealand spokesman said while they were very busy responding to callouts throughout the South Island, Southland had been relatively quiet.

There had been two weather related callouts in the region, one for a blocked drain, and one for an underground garage that had flooded.

FARMERS REJOICE

Southland Federated Farmers president Allan Baird said the overnight rain had come as a huge relief for farmers throughout the region.

'When rain arrives, it doesn't instantly solve farmers' predicaments, but it does alleviate quite a lot of stress.

'A lot of the province has had 40mm or more [of rain], and it's been really beneficial rain. It's certainly recharging a lot of surface water streams and surface water ponds.

'It will be of great benefit to farmers, whose water schemes may have been a little bit less prepared for a one in 15 or 20 year dry [period] that we're currently experiencing.'

Baird said about 80mm of rain would be ideal for replenishing Southland's dry soil.

'That would revive a lot of that 100 to 200mm of top soil, where the bulk of the moisture is needed.

'We are at quite a deficit, so 60 to 100mm would be ideal. Much less than that, we would see an improvement, but to really replenish the soil it will take a fairly large amount of rain to catch up what we haven't had.

'There's no real area in Southland that's better than anywhere else, it's all pretty dry.'

Baird said for farmers, it would take a few weeks before the full benefit of the rain was realised.

'Those grasses will come back reasonably quickly … it's all to do with the depth of the soil, the deeper the soil the more moisture the greases can get access to.

'Cattle like it longer, whereas lambs will be quite happy with small shoots coming through.

'What will give dairy farmers some comfort will take three weeks plus to get reasonable grass on their properties, but it will take less time for sheep farmers.

'At the moment no-one is growing enough grass to feed their cows adequately, so everyone's putting something in additional, whether its silage, palm kernels or barley … Unless a farmer is still on a fully irrigated property.'

Baird said with the current forecast, there was little danger of flooding at this stage.

'Maybe if this was going to last for three days plus, but if it's slowing up by the end of today it shouldn't be to much of a concern.

'Most people are just going to be smiling that they've had a reprieve from a pretty dry period.'

Clutha-Southland MP Hamish Walker said his inbox was flooded with messages of delight from farmers.

'While the rain is a small relief for farmers, we still need plenty more to make a difference.

'I will be home from Parliament around midnight this evening [Thursday], and if it's still raining, I may even sleep on the grass outside to celebrate.'

RESTRICTIONS TO BE MONITORED

Invercargill City Council water manager Alister Murray said the council would be constantly monitoring the rainfall in the region and reviewing water restrictions in the next few days.

The council has banned domestic outside water use.

The council is watching what impact the rain has on the Oreti River, its main water source, and if it rises sufficiently the water ban may be lifted temporarily.

If so, residents will be able to use their hoses, but no decision will be made till noon Friday.

Clutha District Civil Defence staff said a severe weather warning remained in place late Thursday afternoon.

'Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous,' a spokeswoman said.

The public were urged to keep an eye on streams and rivers that may rise rapidly and drive to the conditions.

'Also, remember to be aware of the high tide if you're in a coastal area.'

The Otago Regional Council flood team was monitoring river levels and surface flooding was reported in Milton and Lawrence.