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Starts With A Bang

The Salmon Cannon Is A Stroke Of Scientific And Environmental Brilliance

The story behind the meme is one of those rare cases where everybody wins.

The spectacle of a large fish getting fired out of a cannon has taken the internet by storm.

When salmon swim into the proper location or entry point, they will enter a tube which is then pneumatically pressurized to transport the salmon to the other end, at an elevation hundreds of feet higher than their initial entry point. Once they re-enter the water, they can safely swim away from a point significantly farther upstream. (WASHINGTON STATE UNIVERSITY)

But the Whooshh Fish Transport System uses straightforward physics to solve a complex environmental problem.

The idea of Pneumatic transport became popular in the 19th century, as a pressure gradient in air pressure, by either creating a vacuum ahead of the transported object or a burst of pressurized air behind it, accelerates and transports anything from drugs (in a hospital) to money, checks and receipts (in a bank) to even people in a device such as the one illustrated here. The speculative ‘Hyperloop’ project relies on a similar principle. (ALFRED ELY BEACH)

When placed inside an airtight tube, you can force objects forward by pressurizing air behind it or evacuating the air ahead of it.

The pressure-transport system leveraged in pneumatic tubes and in the Salmon Cannon reached its height in the mid-20th century, when pneumatic tubes were used to rapidly disseminate messages across buildings or even across an entire city, with the proper infrastructure. (ESTHER BUBLEY / UNITED STATES GOVERNMENT)

The pressure gradient exerts a net force on the object inside, accelerating it until it exits the tube.

The most common use for pneumatic tube systems today occurs in hospitals, where drugs, blood, samples, and other small items are rapidly transported from place-to-place internally within the hospital. The same concept can be applied to pretty much any object at all, so long as the correct pressure conditions can be met and will not harm the object being transported. (SWISSLOG HEALTHCARE)

This technique precisely transports materials throughout hospitals, banks, and launches fruit from tree to truck.

Shown here, an example of a salmon cannon enables fish to enter the apparatus from a downstream, below-the-dam location, where they are pneumatically transported up and over the dam, safely deposited atop the structure where they can continue their upstream journey. (© 2019 WHOOSHH INNOVATIONS INC)

A brilliant application by Whooshh Innovations ⁠ — to use this technique on salmon ⁠ — is solving a pressing environmental problem.

In the absence of a dam, fish can swim upstream, even traversing natural obstacles like small waterfalls by propelling themselves up and out of the water. This technique enables the strongest swimmers to climb a fish ladder, but only with a great expenditure of energy: much greater than would naturally be required in the absence of dams. (US DEPARTMENT OF AGRICULTURE / NATURAL RESOURCES CONSERVATION SERVICE)

While human-created dams generate useful, green energy, they disrupt a river’s natural flow.

While dams may be enormously useful to humanity, enabling us to generate power from the flow of a river, they come along with an enormous set of environmental impacts. They disrupt the river’s natural flow, create artificial lakes upstream, they reduce the river’s speed and alter the ecosystem of everything downstream, and additionally disrupt the upstream runs of native fish populations. (PEDRO VÁSQUEZ COLMENARES / FLICKR)

In Oregon and Washington, dams also disrupt the natural spawning runs of the indigenous salmon.

The John Day dam on the Columbia River contains a complex salmon ladder with switchbacks. Only the fish that can navigate their way up this difficult ramp will successfully find themselves upstream of this dam. Dams such as this are enormous obstacles to the original, natural runs the indigenous fish would otherwise occupy. (US ARMY CORPS OF ENGINEERS; ÆVAR ARNFJÖRÐ BJARMASON / WIKIMEDIA COMMONS)

The traditional solution — of installing salmon ladders — stresses even the strongest salmon, sapping their strength.

This fish ladder at the Bonneville dam, which straddles the Columbia river, is extraordinarily difficult for salmon to actually traverse. Only the strongest swimmers make it through, and the journey leaves them fatigued. The number of salmon that can pass each ladder in the upstream journey dwindles progressively; a superior solution has been sought for a long time. (WOODLEYWONDERWORKS / FLICKR)

Gargantuan, ladder-less dams were entirely impassable, until the application of Whooshh’s salmon cannon.

The salmon cannon, as it’s colloquially known, enables a salmon that’s headed upstream to enter a tube where it will be pneumatically accelerated through the tube, where it can gain hundreds of feet in elevation, before being safely deposited in the upstream waters, ahead of any dam it may have otherwise encountered. (WHOOSHH INNOVATIONS / TWITTER)

In 2014, the first salmon cannons were successfully tested at Washington’s Roza Dam.

Pacific Northwest National Laboratory, in this 2015 photo, is shown evaluating the viability of the Whooshh Fish Transport System, a.k.a. the Salmon Cannon, for reducing the impact of hydropower dams on migratory fish. The current fish passage systems, such as ladders and fish lifts, are costly and can harm the fish; tests so far have shown no obvious signs of injury to fish. (PACIFIC NORTHWEST NATIONAL LABORATORY / US DEPARTMENT OF ENERGY)

Thanks to this invention, the Columbia river’s original salmon runs should someday be fully restored, even with the dams present.

Mostly Mute Monday tells a scientific story in images, visuals, and no more than 200 words. Talk less; smile more.

Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.


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