FYFD

Tag: flooding

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    When Rivers Break Their Banks

    Rivers often change their course, but they do not always do so gradually. River avulsions are a bit like earthquakes — they happen suddenly and with disastrous potential. Researchers find that these sudden course changes happen when silt builds up in a river and reduces the amount of water it can carry. Eventually, the resistance to flow is large enough that the river bursts its banks in search of an easier route to the sea. That’s a deadly problem for the communities that live nearby and rely on the river’s sedimentation for their fertile farmland. But using small-scale models, scientists are beginning to unravel the physics behind avulsions, bringing hope that they can be predicted or even sustainably averted. (Video and image credit: Science)

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    Reintroducing Beavers

    Beavers are impressive ecological engineers and a keystone species for wetland environments. But in the UK, it’s been nearly 400 years since beavers were regularly found in the wild. In the meantime, Victorian engineering sensibilities drastically altered the landscape to quickly drain rainwater from upstream locations, which unfortunately increases flooding dangers downstream.

    But all of that is changing with the reintroduction of wild beavers in a Cornwall experiment. Within their 5 acres, the beavers are transforming the landscape by deepening ponds and slowing water drainage. Their dams create ideal habitat spaces not only for the beavers but for many other species of mammals, birds, and insects. Check out the full interview to learn more and see this previous post for a similar effort in the Western U.S. (Video and image credit: BBC Earth)

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    Protecting From Storm Surge

    The most dangerous and destructive part of a tropical cyclone isn’t the wind or rain; it’s the storm surge of water moving inland. This landward shift of ocean takes place because of a cyclone’s strong winds, which drive the water via shear. The depth storm surges reach depends on the wind speed and direction, shape of the shoreline, and many other factors, making exact predictions difficult.

    Fortunately, engineers can — with enough foresight and investment — build structures and networks to help protect developed land from storm surge flooding. (Image and video credit: Practical Engineering)

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    Permeable Pavement

    Controlling storm water is a major challenge in urban environments, where many surfaces are impermeable. In a city, rain cannot simply soak into the ground and filter into the water table. One potential solution is permeable pavement, which uses the same ingredients as its common counterpart minus the sand that usually packs into gaps between the gravel. Without the sand, the final pavement allows water to soak through, as seen above. In practice, the water sinks into a porous reservoir beneath the pavement that helps store and regulate the water’s discharge into the soil.

    Unfortunately, this solution has its limitations. Permeable pavement is not as strong as the regular variety, so it doesn’t work for highly trafficked areas like roadways. It’s also not well-suited to colder areas, where freezing and thawing may disrupt its operation. But it is another tool in engineers’ toolboxes when it comes to keeping urban environments in harmony with nature’s needs. (Image and video credit: Practical Engineering)