New Zealand conservationists have released an adelie penguin back into the sea after the Antarctic-based bird swam thousands of kilometres to make a rare visit. We chat to three climate scientists from the University of New South Wales about how they talk to their kids about the climate crisis. A Decrease font size. A Reset font size. A Increase font size. This story first appeared in Australia Geographic magazine in January, Apart from a soupy stain low on its upstream face, the concrete is spotless and dazzles the eye under the sharp Queensland sun.
This is Paradise Dam, completed in Standing on the dam wall is Dave Murray, who helped design it. Dave, 52, is tall, heavily built and bespectacled. The son of a travelling movie salesman, Dave graduated in civil engineering from the University of Queensland in This is no illusion: it really is massive.
Unlike conventional concrete, which needs days to set, RCC can be built up non-stop in 30 cm layers, Dave says. Like all large dams, Paradise is undeniably an astonishing feat of engineering. The wall is m long and the spillway stands 37 m above the streambed.
When full, it will yield , ML a year for farmers mainly Bundaberg sugarcane growers and 20, ML for homes and industry. But the weather has not been kind to Paradise. At the time of my visit last winter the reservoir was less than 10 per cent full, down from a high of 33 per cent.
A trickle of ML of water a day was being released downstream — hardly enough to operate the fishway effectively or run the 2. There are four types of dams in Australia. Arch dams redirect a lot of pressure to the valley sides. Buttress dams have 45 degree walls that transfer the force downwards. Embankment dams, which are made of rock, gravel and sand, with the finest materials in the centre to form a waterproof core.
Gravity dams are thick, massive structures that can hold back enormous amounts of water under their own weight. High evaporation allows just 12 per cent of our rainfall to run off and reach waterways. European settlers solved this problem with dams. Dam building continued steadily until after WW II, when it accelerated. Today, large more than 15 m high dams store a total of 93, gigalitres.
Even though dams are a major part of modern infrastructure, their positives and negatives on society and the environment are still being studied. Welcome Continue. Energy Tech Tips Community. The Pros and Cons of Dams September 19, Keep reading below for a comprehensive list of the pros and cons of dams: Take action on the climate crisis.
Make the switch to clean energy today. Check availability. Take action on the climate crisis. Keep Reading. During Climate Week in September, we started asking our community to send us their ques At th And not in a good way. The heat wave in Altering the riverbed also reduces habitat for fish that spawn in river bottoms, and for invertebrates.
In aggregate, dammed rivers have also impacted processes in the broader biosphere. Recent studies on the Congo River have demonstrated that the sediment and nutrient flow from the Congo drives biological processes far into the Atlantic Ocean, including serving as a carbon sink for atmospheric greenhouse gases.
Large dams have led to the extinction of many fish and other aquatic species, the disappearance of birds in floodplains, huge losses of forest, wetland and farmland, erosion of coastal deltas, and many other unmitigable impacts. International Rivers is licensed under Creative Commons.
Jump to Navigation. Search form Search. Large dams all over the world provide necessary services such as hydropower, flood protection, and water security. The iconic Hoover Dam, for example, generates enough hydropower to serve 1. Fish and other native river species have evolved to thrive among particular natural patterns of river flow that provide cues for migration and reproduction. Large dams interrupt these cues , which can interfere with the life cycles of native species.
Worse, these disruptions can lead to newly-suitable habitat for harmful invasive species. So how can we balance our need for water against maintaining the river-flow patterns that sustain freshwater ecosystems downstream of dams, especially in a changing climate?
In recent research published in Nature Communications , my colleagues at the University of Washington and I looked at potential improvements in dam operations in the hopes of avoiding a world of dwindling water and invaded rivers.
And this river system made for the perfect case study as it epitomizes the water conflicts that arid regions of the world are facing. On the one hand, the reservoir created by the Navajo Dam holds a capacity of over 1. But on the other hand, the San Juan River is home to multiple endangered, native fish species, such as Colorado pikeminnow and razorback suckers.
The construction of the Navajo Dam enables multiple invasive fish to thrive, including common carp and channel catfish, which compete with native adults for food and prey on the juvenile fish. Colorado pikeminnow and razorback suckers were put on the Endangered Species Act list in part because of these invaders. We wanted to know: Is it possible to have a triple-win of meeting agricultural water needs, benefiting native fish species, and deterring invasive fish species?
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