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Dams and crops boosted across WA's south-west amid near-record July rainfall in Perth

Monday August 2, 2021 - 10:45 AEST
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Kevin Thiele expects this year to be a bumper wildflower season following the heavy rain. - ABC

Drenched soils of Perth and the south-west corner of the state are breathing life back into the landscape, with the region anticipated to be awash with colour this wildflower season.


Dams, which have been at record lows for the past two years, are filling to the brink throughout the Great Southern, while streamflow has been boosted by 80 per cent in the metropolitan area.


And there is a good reason for it. 


With figures officially in, the record books show it was one of the wettest Julys in decades for Perth.


The city recorded 271 millimetres of rain for July, just shy of the record for Perth's official site in Mt Lawley, set in 1995.


Bickley recorded 459mm for the month, making it the wettest July since records began in 1969, while Jarrahdale also saw over 400mm during the month.


And the rains extended far beyond the metropolitan area, with above-average to well-above-average rainfall recorded for most areas from the Gascoyne to the south-east coast, indicated by green and blue shaded areas of the map below.


The rainfall figures of this year come in stark contrast to recent years in south-west WA.


Since 2006, every winter bar two have seen below-average to very-much-below-average rainfall in the south-west of WA.


Many have compared this month to what was more common prior to the 70s.


So what does this return of rainfall mean for the landscape, agriculture industry and water supply? 


Landscape comes alive


Botanist and taxonomist Kevin Thiele, who is president of the Wildflower Association WA, said the south-west land division was on the cusp of a bumper wildflower season. 


"This is a cracker of a season, there's no doubt," he said.


"There's the field of daisies, which is when you get rain in the Mulga lands so Paynes Find, Cue, that sort of area you get fields of annuals and that's happening this year. 


"Elsewhere in the south-west land division it's more you get flowering shrubs, so really rich, interesting and diverse wildflowers, but not the fields of wildflowers."


Having come back from a recent trip through the Rangelands, he said the landscape was "bouncing".


"The first thing you notice [is] just how much water is lying around ? there's water in the paddocks, the lakes, the ground is actually sodden in some places," he said.


Mr Thiele said it was important to remember one season would not repair damage of recent dry years. 





Meanwhile, Department of Biodiversity and Conservation flora conservation officer Ben Lullfitz said wetlands were brimming with life.


"It's really great for our native fauna, especially our water birds and amphibians," he said.


But the wet weather carries some risk of disease spread.


Mr Lullfitz said dieback ? one of the biggest threats to flora in the south-west ? was at increased risk of spread with the wet weather.


He said people needed to make sure they were vigilant in cleaning their vehicles and footwear prior to entry into native vegetated areas. 


Dam levels rise with streamflow


The July rainfall has gone a long way in boosting Perth's metropolitan water supply, following on from a dire streamflow in June, where just 5 per cent of the average trickled into metro dams. 


A spokesman for the Water Corporation said July's rainfall had accounted for more than 80 per cent of streamflow into Perth dams this year.


"Since January, we've received 39.03 billion litres of streamflow into Perth's dams," he said.


"Of that, 35.07 billion litres [was] received in July alone."


But, for Perth, figures are still a long way off what they used to be, with streamflow for the year 146 billion litres less than what the metropolitan area could expect between 1911 and 1970.


"It's been many years since Perth could rely exclusively on rainfall for our water supply needs," he said.


'Steady' falls boost crops


Through the Great Southern, several dams are full to the brink, including Denmark's Quickup Dam which has reached its highest level in 15 years. 


Total dam capacity for the region is at 89 per cent, up more than 30 per cent on last year when emergency livestock water carting was required through an unprecedented number of farming districts.


As of this month, the final two of 12 water deficiency declarations that stretched back to May 2019 were revoked.


Ravensthorpe farmer Brad Clarke, who was carting water on his property last year amid prolonged dry conditions, said it had been a "complete change".


"This year has been not only good rainfall to the end of July but it's been timely, and steady falls," he said.


Unlike many other areas, he has not had water pouring down the creeks and dams overflowing.


But he said gradually the dams were still filling up.


"Half are full and the other half have a reasonable amount of water in them when last year we were completely empty.


"It's certainly a welcome change."


Ravensthorpe farmer Jenny Chambers said the farm was "looking beautiful".


"The fact we've had rainfall in double figures is the biggest thing, because over the last three years we've probably only had four events where we had over 10 millimetres of rain," she said.


But she said it was important for the government to keep up the momentum in making sure water was readily available for carting and in fire emergencies.


'Just amazing crops'


For most of the WA grains industry, this year is shaping up to be a bumper crop.


The latest Grains Industry of WA (GIWA) crop report is estimating a record harvest of 19.6 million tonnes.


WA Farmers president John Hassell said it was looking "very exciting at the moment".


"Make no mistake there are some negatives, but on the whole I think the state stands to do very well out of it," he said.


"I got told of a 6'6" bloke walking through a canola crop [in Mullewa] and you can't see his head.


"There's just amazing crops around the place, but we're not out of the woods yet, there's still a frost risk so it's never really over until the grain is in the bin."


However, for some areas of the south coast, the rain has had consequences.


GIWA tonnage estimates for the Albany Port zone and the coastal strip in the Esperance Port Zone are down at least 10 to 15 per cent on last year.







- ABC

© ABC 2021

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