| World news New Zealand Raising Warragamba dam declared a critical project for NSW


The New South Wales (NSW) government in Australia has declared plans to raise the Warragamba Dam wall by 14m as Critical State Significant Infrastructure (CSSI), stating that it is deemed essential for NSW for economic and social reasons. Premier Dominic Perrottet said the proposal to raise the dam would save lives, save properties and would help future-proof Western Sydney from flood risks. “First and foremost my number one priority as Premier is


protecting NSW communities and we know from the independent flood inquiry that the best way to protect communities downstream is to raise the wall,” Perrottet said. “This declaration reinforces that raising the dam wall is the most effective long-term flood mitigation strategy to help protect residents across the Hawkesbury-Nepean. This region has been hit hard by floods and we are committed to progressing this important project to make sure residents have genuine flood protection into the future.” Minister for Lands and Water Kevin Anderson added that the importance of the dam was highlighted in the recently released Greater Sydney Water Strategy that showed the significant risks and costs of alternative proposals such as Labor’s plan to lower the supply level.


“In a flood similar to the worst on record in the valley, the number of homes impacted would drop threefold from 15,500 to 5,000, while


14,000 people would need to be evacuated rather than 90,000. The cost of damages would also be reduced by up to $8 billion,” Anderson said. “Labor’s plan to lower Warragamba’s water supply level by 12 metres would have severe consequences such as putting Sydney into severe water restrictions and increasing people’s water bills.”


Minister for Planning and Minister for Homes Anthony Roberts said the CSSI declaration would not impact the rigorous assessment and stakeholder scrutiny the proposal would need to go through. “The proposal has already been subject to an 82-day public


exhibition, which gave stakeholders a chance to provide their feedback,” Roberts said. “The recent flood inquiry confirmed that raising the Warragamba Dam wall is the most effective flood mitigation option available to us. This proposal doesn’t hurt us during drought, but will protect us during floods, balancing the natural extremes that are becoming more frequent.” WaterNSW will respond to the feedback and issues raised in submissions and its Preferred Infrastructure Report, before a comprehensive assessment is undertaken in accordance with the Environmental Planning and Assessment Act. Located about 65km west of Sydney on the Warragamba River,


Warragamba Dam is one of the largest domestic water supply dams in the world.


US Hydro provides reliable electricity even during historic droughts says new study


A new study funded by the US Department of Energy’s Water Power Technologies Office (WPTO) has found that hydropower has continued to provide reliable electricity even during times of historic droughts. The Pacific Northwest National Laboratory (PNNL), with funding from WPTO, conducted a multi-regional study of drought’s impact on 21st century hydropower generation in the western US – with the report the described as the most comprehensive look into the effects of drought on hydropower generation in the US this century. The analysis reveals that though drought does raise concerns for hydroelectric generation, the overall hydropower fleet sustained 80% of its average generation for the years 2001-2021. Also during this time period, hydropower could still be relied upon to supply flexible power during periods of high energy demand, even during the most severe droughts of the past two decades. The western United States has always been a region of extreme climate variability, with large fluctuations in rain and snowfall precipitation from year to year. Climate change, and especially extreme weather events such as droughts and floods, is only increasing those fluctuations. This has enormous implications for the energy grid, sanitation, drinking water, food and agriculture, and more.


In a wet year, hydroelectric power can meet 30% of annual western electricity demand, but that number can drop below 20% when less rain and snowfall lead to lower water levels in rivers and reservoirs. The PNNL study looked at eight climate


sub-regions across 11 western states, including Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. This area, which the US Census Bureau defines as the “West,” contributes more than 60% of US hydropower capacity. All data used in the study is publicly available and taken from the US Energy Information Administration, the US Geological Survey National Water Information System, the US Drought Monitor, the National Centers for Environmental Information of the National Oceanic and Atmospheric Administration, and Oak Ridge National Laboratory. That data indicated 2021 to be the second


worst year for drought this century, with overall hydropower generation 16% lower than the average since 2001. The 2021 drought most severely impacted hydropower generation in California (48% below average) and Oregon (16% below average). However, the large sizes of western states, and wide range of weather across the West means drought rarely impairs hydroelectric power across all climate sub-regions simultaneously. Consequently, the overall hydropower fleet remains reliable even if certain plants or sub-regions produce less power. Washington and Idaho, for example, only experienced an average drop in


hydropower generation of about 12% in 2021, and the entire western hydropower fleet was still able to maintain 84% of its average expected generation. 2001 remains the worst year for western


hydropower generation this century, owing to extreme drought in the Pacific Northwest where two-thirds of western hydropower capacity is located. Despite the drought, the hydropower fleet still provided 150 TWh of renewable- generated electricity. This means that, even in its worst year this century, the overall hydropower fleet sustained 80% of its average expected generation. Multi-year drought does mean that sub-


regions of the West, such as particular states or parts of states, can experience a significant decline in hydropower generation. In California, there was evidence of significant curtailments in monthly output as reservoirs drop each time the region experienced two or more years of drought. Yet even within these regions, local hydropower is still reliable and an important energy source: data shows that hydroelectric power in California continued to ramp up in the evening through summer 2021, supplying essential power to the grid as demand increased and solar generation decreased. Annual hydropower generation across most


sub-regions has a strong correlation with yearly rainfall totals, allowing researchers to further create hydropower generation estimates for years lacking energy generation data. Based on these estimates in combination with rainfall outlooks for the remainder of 2022, the


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