Snowy’s cloud seeding

Snowy Hydro has been investing $2.4 million per year on cloud seeding projects and scientific research trials, since 2004.

The program was bolstered in 2006 when the Commonwealth government awarded a $4.02 million grant to Snowy Hydro under the Renewable Energy Development Initiative for research support.

The heavily scrutinised research trials have now produced evidence which shows cloud seeding into suitable weather events can increase snowfall in target areas by an average of 14 per cent.

But it has also proved there are no adverse environmental impacts or side effects on rainfall or snow patterns, downwind of the target area.

The results of Snowy Hydro’s trial work have been supported by two separate independent scientific peer reviews, with the research subsequently published in the peer reviewed Journal of Applied Meteorology.

In the latest edition of Snowy Hydro News, Snowy Hydro scientific services manager Loredana Warren said the published results were also similar to other results reported from cloud seeding studies undertaken by the CSIRO in the Snowy Mountains from 1955-59.

“The exceptional scientific merit of the program and absence of adverse environmental impacts have been sufficiently compelling for the government to announce that it will now pass the necessary legislation for an ongoing, operational cloud seeding program to commence from the winter of 2013,” Ms Warren wrote.

Snowy’s initial cloud seeding activity was spread across approximately 1000 square kilometres in Kosciuszko National Park’s main range.

The six-year trial period was governed under tight restrictions imposed by NSW State Government legislation, which defined the target snowfall area for cloud seeding events.

That legislation has been amended in recent months due to the successful research results, granting Snowy Hydro permission to expand its cloud seeding target area.

A review by the NSW Natural Resources Commission concluded there was “no evidence of the trial having any adverse environmental impacts, including adverse impacts on rainfall in down-wind areas”.

Snowy Hydro Executive Officer for Production Water and Environment David Harris said that independent scientific evaluation gave the NSW government the evidence it needed to bolster his company’s cloud seeding activities.

Mr Harris said randomised cloud seeding events were no longer required, to satisfy the scientific trials and they can now seed suitable weather events, in a purely operational program.

The new rules also provide scope for cloud seeding from aeroplanes, if Snowy applies for permission.

But he said the company has no plans to utilise that method, in the near future.

Mr Harris said they still needed environmental approvals from the NSW Environment and Planning Ministers, and permission to use the different chemicals and tracing agents, required in the cloud seeding program.

He said they can only cloud seed to produce snow above 1400 metres, and not rain, to ensure they avoid any potential negative impacts or damage to the region’s lucrative skiing and tourism industry.

They are also prevented from releasing cloud seeding agents and installing new equipment in Wilderness Areas, including the Jagungal Wilderness Area.

While the scientific trials have been dropped, they must still produce an annual environmental report on program’s operations, for the relevant Ministers.

Mr Harris said the cloud seeding program worked closely with the local skiing industry throughout - to ensure they were properly consulted and understood only snow would be produced and not rain.

Snowy’s cloud seeding technique is similar to many other programs used in other parts of Australia like Tasmania and around the globe, in particular Japan.

Silver iodide is fired into suitable clouds at opportune times, to stimulate the formation and growth of ice crystals or raindrops, which enhances the volume of snow or precipitation produced by the clouds.

The silver iodide is released from 23 launch sites strategically located west of the target snowfall area in the Snowy Mountains.

Seeding takes place during the winter and any additional water is predominantly produced during the spring season when snow melts and runs down the mountains into the Snowy system’s various water catchments.

The target area is being increased under the new regulations, with Mr Harris saying that they are expecting to add only a few additional launch sites, located strategically to suit the expanded snowfall zone.

One of the key criticisms of cloud seeding historically has been whether or not the anticipated added precipitation, or different chemicals used in the cloud seeding methods, do create any negative side effects.

The biggest fear is that additional or unwanted rain may be produced where it’s not wanted in fringe areas downwind of the target zones, or rainfall may be “stolen” from regions further along the cloud system.

But Mr Harris said Snowy’s scientific evaluation had proven the extra snowfall doesn’t generate any adverse environmental impacts or downstream harm, which was backed by an independent review.

He estimated that up to 80 gigalitres of extra water flow per year can be converted from the additional snowfall.

But he said while showing promising results, that estimate wasn’t as conclusive as the evidence which showed cloud seeding into suitable weather events can create up to 14pc additional snowfall.

Mr Harris said publication of Snowy’s cloud seeding work in peer reviewed scientific journals had also attracted international acclaim, with program managers invited to speak at scientific conventions, while earning other commendations and recognition.

He said evidence of the trial work showed the 14pc increase of snowfall in the target area will most likely stay the same.

But the potential water-flows can be increased due to the additional seeding opportunities and the expanded target area allowed now, under the new State government regulations.

NSW Irrigators Council Chairman Richard Stott was one of several irrigation company leaders who toured Snowy Hydro’s facilities recently.

They learned about the work being done to increase snowfall and therefore water flows, through the company’s cloud seeding program.

Mr Stott said Snow Hydro’s cloud seeding program was producing “terrific” results and welcomed the additional water-flows.

He said eight years of trial work had produced scientific proof of a 14pc increase in snowfall in the target areas, while also showing no adverse side effects or environmental harm from cloud seeding work that was constantly monitored.

“This work has been backed by independent science, showing there are benefits for everyone,” he said.

“More snow means more water for power generation but also irrigators and the environment.

“Everyone’s having a win here.”

Mr Stott said he’d like to see cloud seeding technology explored even further, to find out if the 14pc snowfall increase can produce even more water in the spring season, when snow’s melting and running down the mountains into water reserves.

“Anything that can improve the potential water catchment in the Snowy Mountains for producers and irrigators and the environment can only be good for everyone and should be looked into,” he said.

Mr Stott said he also gained a better understanding about the operational constraints that Snowy Hydro faced in balancing water use for power generation, with downstream flows into irrigation farming areas along the Murray-Darling Basin, like the Murray, Murrumbidgee and Coleambally regions.

He said he now had greater understanding of why water was being released at different times of the year for different reasons, around power generation and other variable factors, including the environment.