Australasia | Facing up to the change The impact of climate change continues to be felt throughout Australia and New Zealand
NEW ZEALAND ENERGY COMPANY Meridian was given cause for celebration when levels of the country’s largest hydro storage lake, Lake Pūkaki, rose above average for the first time in months. Much missed rain from April to August, which finally arrived in September, meant the company’s hydro lakes were being managed extremely carefully.
Above: Lake Pukaki dam in New Zealand. Careful management of Meridian’s hydropower facilities was required before much needed rainfall arrived in September
As Meridian General Manager of Wholesale, Chris Ewers, said: There’s nothing like a helping hand from Mother Nature.” Lake Pūkaki was below average for more than 150 days, and at historically low levels, before weeks of heavy rain and snowfall changed the outlook. During the beginning of October it rose 715mm to just over 525m above sea level - 102% of average for the time of year. September rain exceeded expectations and the
Waitaki catchment, which feeds Lake Pūkaki and the Waitaki Hydro Scheme, had its fourth wettest September on record. It’s not just water in the lakes that’s welcome though, as Ewers pointed out, in the mountains above the Waitaki catchment snow storage is now sitting at 117% of average. “That’s great news for later in the season as the snow melts and feeds the lakes throughout the warmer months. After a challenging winter, we couldn’t have asked for a better start to spring,” he said. On 20 August the snow base had been just 63% of average – the lowest recorded for that time of year, while it had been as low as 58% of average earlier in the season. Heavy snowfall soon saw snow storage in the Waitaki catchment rocket to 105% of average, up from 83% in mid-September.
Weather patterns Recent research in New Zealand has also been
Above: Exposed lakebed in the high country of New Zealand after a dry summer period. Challenges need to be confronted as the impact of climate change continue
investigating the impact of climate change on weather patterns. As Luke J Harrington et al acknowledge in Environmental Research Letters, understanding any changes in daily rainfall is particularly pertinent for a temperate, mid-latitude and topographically complex country like New Zealand, which relies primarily on
rainfed pastoral agriculture and has a diverse array of rainfall regimes that differ significantly over short distances. The researchers made use of thousands of regional
climate modelling outputs from the Weather@Home project to resolve how the wettest and driest days of the year will respond to simulations of a 3°C world, relative to simulations of the climate of the recent past (2006–15). With results projecting increases in the volatility and unevenness of daily rainfall across New Zealand, the research team says it’s further evidence of the challenges which must be confronted if global temperatures continue to increase rapidly over the twenty-first century.
WaterNSW WaterNSW has rolled out an enhanced flood
training programme for specialist dam operators at regional dam sites across Australia, significantly adding to the number of skilled personnel across multiple river valleys. Record numbers of WaterNSW dam operations and planning staff have recently completed training at Wyangala, Keepit, Copeton, Burrendong and Burrinjuck dams, gaining critical flood management skills at multiple locations. The expanded training follows international
awards in November last year recognising WaterNSW for innovation in the recruitment, retention and development of critical water management specialists whose functions include flood planning and response.
General Manager of Water Planning and Delivery,
Ashley Webb, said the latest training introduced new staff to flood operations, and broadened the skills of existing team members to be familiar with multiple dams. “WaterNSW crews are well-recognised as expert dam operators and we maintain that standard through selective recruiting and consistent training in this niche field,” he said. “Flood preparedness and response is critical to safeguarding our communities,
Right: Radial spillway gates of Wyangala Dam at the junction of the Lachlan and Abercrombie Rivers, in New South Wales, Australia. The dam was built for flood mitigation, hydroelectricity and irrigation
14 | December 2024 |
www.waterpowermagazine.com
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