Snowy melt can be hit and miss but releases will be fine

Big snow melt not always assured after good season in Snowies


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The Eucumbene river is in full flow but a good snow season doesn't always assure a big snow melt, with sublimation, evaporation and spring rains all playing a part in how much water ends up in the catchments.

The Eucumbene river is in full flow but a good snow season doesn't always assure a big snow melt, with sublimation, evaporation and spring rains all playing a part in how much water ends up in the catchments.

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Decision on huge Snowy 2.0 scheme within weeks

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It was one of the best snow seasons in years but yet the expected run-off into water storages in the Snowy Mountains was disappointing.

But Snowy Hydro chiefs say this will not affect water releases to irrigators and all licence requirements will be met.

Snowy hydro chief executive Paul Broad and Roger Whitby, chief operating officer, sat down with The Land  to explain some of the reasons the run-off wasn’t as large as expected.

Meantime, a decision on whether the $4bn Snowy 2.0 pumped hydro scheme will go ahead is only weeks away, with the Snowy Hydro board set to meet.  Already works are underway to build a camp for workers at Lobbs Hole and consideration is being given to creating a new road to access the top of the project at Tantangara reservoir.

Mr Broad would not say what he thought the final outcome would be but said the recent contract process to find renewable energy suppliers for Snowy Hydro’s own plant, showed that Snowy 2.0 ticked all the economic boxes.

Snowy Hydro says despite some dams in the scheme being at levels only half of where they were this time last year, the company would meet all its irrigation and energy requirements and targets for summer.

Snowy Hydro uses the Spencer Creek snow depth reader every year and as at August 9 this year the snow depth was equal to the famous 2000 season, a depth of 180cm. (In 2000 later snow took the depth to over 250cm).

Mr Broad said it was extraordinarily dry snow that fell during the snow season this year.

Also the warm early spring rain didn’t eventuate that is vital in carrying the snow melt down through the intricate system of aqueducts and pipes in the mountains (80km of them in the Snowies) to help boost the catchment.

Mr Whitby said that there was also snow evaporation because of the warmer end to the season, that meant the melt was smaller. Water run-off is also lost through sublimation.

Storages though at Eucumbene, that was sitting at historically low levels of about 18 per cent two months ago have slowly climbed back to about 25 per cent, with good rain in the west of the Snowies now helping boost water levels. Only last year Eucumbene was sitting at 45 per cent capacity.

Mr Broad said they had not increased energy production, and so this didn’t have an effect on storages.

He said in a good year Snowy Hydro was always open to discuss extra releases with irrigators. (Snowy Hydro does not regulate water licences).

The huge Snowy 2.0 pumped hydro scheme is set for a big tick within weeks.

The huge Snowy 2.0 pumped hydro scheme is set for a big tick within weeks.

At this stage Jindabyne was sitting at 26 per cent and Tantangara, the head of the Snowy 2.0 project, was sitting at 26 per cent capacity, but filling quickly with the good rain. Cloud seeding during the snow season had boosted snowfall by about 14 per cent to the events.

“With the drought the ground has been very dry so the run-off hasn’t been as great,” Mr Broad said.

“These are not unusual things to happen either,” he said.

Snowy Hydro’s long-term forecast was for a dry period from January to March, but a return to normal weather patterns in autumn.

Related: Drilling down 1km to test rock for Snowy 2.0 scheme

Snowy Hydro would be “pinching a bit of its water from next year”, to put down the river systems this year.

Snowy Hydro is also required under licence to release environmental flows down the Snowy River, that it has been doing over the last few months from Jindabyne dam. 

Snowy Hydro said it was in a good position to meet the energy needs of its customers this summer.  The Snowy Scheme has experienced some good water inflows over recent months, with decent rain topping up our water storages. 

Snowy Hydro’s CEO, Paul Broad said that for more than 65 years the company had successfully managed the Scheme through periods of high inflows and very severe droughts. 

“Over winter and spring, about 1,200 gigalitres of water has reached the Scheme, which is enough to fill Sydney Harbour more than twice. We know how to best manage and use our water and we have been conserving water over the last six months to ensure we’re ready to go this summer. 

“Snowy Hydro constantly monitors inflows and weather forecasts to plan for current and future operations to balance short and long-term energy and water needs.”

The company says Lake Eucumbene is the Scheme's largest storage and plays an important role in regulating highly variable inflows over years and decades. It rises and falls over much longer periods than many of our other reservoirs. Lake Eucumbene is situated in the middle of the Scheme, giving us plenty of flexibility to store and move water around. Snowy Hydro will also continue to make downstream water releases in compliance with our water licence for farmers and environmental flows. 

“This summer, like decades of summers before, we’re ready to keep the lights on. We’re able to respond to the market’s needs to help provide stable, reliable and affordable energy over the coming months,” it said.  

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