Why Are There No Bridges Over the Amazon River? (livescience.com) 31
LiveScience reports:
Despite being around 4,300 miles in length, the Amazon River surprisingly has no bridges.
The Amazon River is the world's second-longest river and one of the planet's most significant waterways... Given the Amazon flows through three countries (Peru, Colombia and Brazil) and more than 30 million people live in the river's basin, according to the World Wildlife Fund, it seems somewhat improbable that no bridges span the river. So why is this the case? Are there fundamental difficulties with building such structures in a rainforest containing swaps, extensive wetlands and deep, thick undergrowth? Are there financial barriers? Or is it simply not worth the effort?
The site got answers from Walter Kaufmann, the chair of Structural Engineering at the Swiss Federal Institute of Technology in Zurich. Long-time Slashdot reader fahrbot-bot shared this summary of the explanations (condensing quotes from the article):
The Amazon River is the world's second-longest river and one of the planet's most significant waterways... Given the Amazon flows through three countries (Peru, Colombia and Brazil) and more than 30 million people live in the river's basin, according to the World Wildlife Fund, it seems somewhat improbable that no bridges span the river. So why is this the case? Are there fundamental difficulties with building such structures in a rainforest containing swaps, extensive wetlands and deep, thick undergrowth? Are there financial barriers? Or is it simply not worth the effort?
The site got answers from Walter Kaufmann, the chair of Structural Engineering at the Swiss Federal Institute of Technology in Zurich. Long-time Slashdot reader fahrbot-bot shared this summary of the explanations (condensing quotes from the article):
- There are technical and logistical difficulties.
The Amazon is far from an ideal location for bridge builders. It has an array of natural stumbling blocks that would need to be conquered by engineers and construction workers. its extensive marshes and soft soils would necessitate "very long access viaducts and very deep foundations," and this would require hefty financial investment. Additionally, the changing positions of the river's course across the seasons, with "pronounced differences" in water depth, would make construction "extremely demanding."
- The environment at the Amazon is certainly among the most difficult in the world.
Pontoons, or floating structures, are not a solution that would work in most parts of the Amazon, Kaufmann said, because the river is hugely impacted by seasonal variances, which adds an additional layer of complexity. For instance, during the dry season — between June and November — the Amazon averages a width of between 2 and 6 miles (3.2 and 9.7 km), while in the wet season — December through April — the river can be as wide as 30 miles (48 km), and the water level can be 50 feet (15 meters) higher than it is during the dry season, according to Britannica.
- There is no sufficiently pressing need for a bridge across the Amazon.
The Amazon, for much of its 4,300-mile (6,920 kilometers) length, meanders through areas that are sparsely populated, meaning there are very few major roads for any bridge to connect to. And in the cities and towns that border the river, boats and ferries are an established means of moving goods and people from bank to bank, meaning there is no real need for bridges to be built, other than to make trips slightly quicker.
Bridges (Score:5, Insightful)
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There's a shitload of money to be made in building bridges, that's why.
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Yep. The bridge lobbyists need a shortlist of points that need addressing before they start campaigning.
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I think that the article answers the question pretty clearly.
Yes, although point 3 is really the only one that matters.
If anyone had identified a need for such a bridge, civil engineers would have solved points 1 and 2 decades ago.
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Some ancient cities have been recently found by lidar - if they prove useful it might come up.
Re:Bridges (Score:5, Interesting)
Someone asked the question because it is an interesting question. If people didn't ask questions that others think are pointless, then we wouldn't have pens that can write upside-down, online streaming of video, or even websites like slashdot.
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The real question is, why did anyone ask this in the first place? It does not seem to be one of the world's pressing questions.
I just listed to an Oxford professor explain on a podcast what would happen if the Earth suddenly turned into blueberries, which he wrote a paper on for no reason other than that it was a fascinating question asked on StackExchange (answer: blueberry jam geysers that rocket out of the atmosphere, the moon eventually crashing into us, and all sorts of other fun). If questions like these don’t pique your interest, I’d have to ask whether you’ve lost your sense of curiosity.
Increased economic activity (Score:2)
The amount of economic activity to be gained by literally bridging such a huge barrier to trade would be immense. There are a lot of people down that way who don't have a lot of money and infrastructure like this could generate the wealth to pull some of them out of poverty.
Don't give them ideas (Score:3, Interesting)
It already seems to be open day in the Amazon for loggers and cattle farmers thanks to that Bolsonaro idiot with highways being bulldozed through the forest. I wouldn't be surprised if a bridge doesn't turn up before long.
Unlikely (Score:3)
Amazonia is in the middle of nowhere and there's not much there other than Manaus. Parts of it burn all the time because it's like an ocean of trees and the Brazilian government hasn't got things together enough to stop that so Amazonia kinda does its own thing. This isn't anything new, it hasn't had things together for a long time. There's a reason they look back to Juscelino Kubitschek so fondly and I bet most of you don't even know who the hell that is.
Bolsonaro isn't likely to do much to Amazonia goo
There is also no road from N to S america (Score:5, Interesting)
Technically the skill is there. Colombia is finishing the building of 24 km of road tunnels through the Andes for truck traffic. Rather than going up 2.5 km they just go through. I think the longer tunnel is around 8 km.
Of course the Americas are sparsely populated. In the US the flyover states have more livestock than people, or are just inhospitable. In South America, there are vast regions of forest. And no one has money for bridges to nowhere.
Re:There is also no road from N to S america (Score:4, Interesting)
Panama had funds allocated to close the Darien Gap while Noriega was president, IIRC a British company had been contracted to do the engineering. After the US invasion those plans were cancelled. I was told by someone who seemed knowledgeable that the generals in DC wanted to ensure that an invasion force couldn't travel by land the full length of the Panamerican Highway to the southern border of the US, although it seems absurd he had retired from the Pentagon just a few years earlier.
There used to be a regular ferry that went around it, but that seems to have shut down as well for some reason.
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I would find it much more likely that the US has an interest in Latin America having a natural restriction on trade. Forcing trade to go by-ship increases its costs and requires a minimum size to the players compared to what can be transported over road or rail.
It also wouldn't surprise me if the desire to restrict trade is to make it harder for the drug trade towards the US.
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The Darien pass is pretty much impassable. Land rovers have made it through but building a road would be a technical fear and environmental destructive.
Technically the skill is there. Colombia is finishing the building of 24 km of road tunnels through the Andes for truck traffic. Rather than going up 2.5 km they just go through. I think the longer tunnel is around 8 km.
The technical skill to build a road through the Darien gap is definitely there. Has been for years, it would be less challenging than building the Tunel de Oriente between the Colombian city of Medellin and the airport at Rio Negro, which is 8.1 KM (different scale though). However unlike that tunnel, there is almost zero demand for it. It goes from a place where no-one lives in Panama to a place where no-one lives in Colombia. You'd be linking where Panamanian highway 1 ends to somewhere along Colombian hi
Only once the name changes (Score:5, Interesting)
There are plenty of bridges upriver, it's only bridge-less once the name changes to Amazon. Whether you consider the Apurimac or the Vilcanota the origin of the Amazon there are a variety of bridges across it, some of them stunningly beautiful. The one over the Vilcanota at Tinta is over 400 years old, near the headwaters there is a stone slab bridge that probably predates the Inca. There are several paja-grass suspension bridges on the Apurimac, the bridge near Paruro hosts a huge whirlpool during the rainy season, and the road from Paquaritambo to Santo Tomas has 17 switchbacks between the top of the valley and the bridge on one side and 11 on the other side.
Bezos (Score:2)
Why ruin the ferry business? (Score:2)
The river is 2 to 5 miles wide at best and depending on these season 30 miles.
Nobody has the money for such bridges.
Re: Why ruin the ferry business? (Score:2)
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Uh, because... (Score:2)
Because no one wants to get to the other bank.
They won't do it. But what we can't do is worse. (Score:2)
And North Carolina can't build a bridge [11foot8.com] that shipping containers can fit under. Brazil and The USA are so backwards infrastructurally.
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My post was meant tongue-in-cheek. But more seriously, all I hear are excuses for an infrastructure problem that doesn't appear in most of the world.
I'd turn that route into a bike and footpath. And make anyone still not using public transportation drive 15 minutes out of their way every day.
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They did fix it, as it is now 12 feet 4 inches. There is no practical way to provide more clearance as explained very well by the web site you linked to.