Why are there no bridges over the Amazon River? There are no bridges over the Amazon River because the majority of it goes through thick rainforest where there are no roads and not enough people to need bridges.
The Amazon River is either the second longest river in the world or the longest river in the world depending on how you measure it. The Nile is 6,650 km long and the Amazon is 6,400 km long. Most people recognize the Nile River as the longest, but it is very tricky to measure the length of a river because the source can be difficult to pin down and a lot of rivers spread out into tributaries. Still, whether it is the longest or not, the Amazon is still an incredibly long river. What the Amazon River loses in length, it more than makes up for with volume. The Amazon River has a water discharge of about 230,000 m3 per second. The Nile River has a water discharge of 2,830 m3 per second, almost one hundred times lower. This comes down to the Amazon River’s location. It runs through the Amazon rainforest and is the largest drainage basin in the world. It can be hard to imagine water volume in cubic meters. An Olympic-sized swimming pool is 2,500 m3 of water, which is 2.5 million liters. The Nile River puts out slightly more than one Olympic-sized pool a second and the Amazon River puts out 100 hundred of them. That means the Amazon River could fill 100 Olympic swimming pools, to a total of 250 million liters of water, every second!!
The source of the Amazon River is a tricky subject. The Amazon River doesn’t have a single source, but is formed by four small rivers that come together. Wherever its source, it is high up in the Andes mountains. From there the river flows east, all across the widest point of South America, before it joins the Atlantic Ocean. On its way, it is fed by a huge number of other rivers that flow out of the Amazon Rainforest.
So, why are there no bridges over the Amazon River? There is one bridge that crosses a tributary of the Amazon. The Rio Negro Bridge spans the Rio Negro, just before it joins the Amazon River. This bridge is 3,595 m long and it has sparked a lot of argument because it cost a lot of money and doesn’t really appear to go anywhere. It links a large city with a small town and has been called a “bridge to nowhere”. Still, it is the only bridge that is anywhere near to the Amazon River. There are several reasons why there are no bridges over the Amazon. These are low population, established infrastructure, the rainforest, conservation, the water flow, and the soil.
The first issue is that for most of the Amazon’s path, there are not that many large settlements. The forest is too thick and it is too hard for people to live. The settlements are small and far between. There would be no need to join any of them with bridges. And the second reason is that all of these communities are used to crossing the river by boat. There are some larger cities along the river, but they also have a ferry infrastructure. That is not to say that bridges can’t be built. London used to have a ferry infrastructure across the Thames, but bridges were still built. It just means that bridges are not currently necessary.
The third reason is the rainforest itself. To build a bridge would mean building a road. There would have to be a way to get the workers and the materials to the construction site. The rainforest is incredibly thick and that would not be easy. It would also mean a lot of deforestation. One of the criticisms of the Rio Negro bridge is that the government intends to build beyond the small town that the bridge connects to.
The last two reasons are connected. It would be difficult to build a bridge across the Amazon because of its incredible flow rate. The river is liable to flood and the power of the water constantly erodes the soil along the banks. The water in the Amazon is very muddy because of all the sediment it is carrying. Any bridge built over the river would have to cope with changing bank, flooding, and very soft sediment to build on. All of these problems could probably be overcome if someone wanted to build a bridge, but there is just not enough need for a bridge to spend the money it would take. And this is what I learned today.
Sources
https://www.livescience.com/why-no-bridges-over-amazon-river
https://en.wikipedia.org/wiki/Rio_Negro_Bridge
https://en.wikipedia.org/wiki/Amazon_River
https://en.wikipedia.org/wiki/Source_of_the_Amazon_River
Photo by Nando Freitas: https://www.pexels.com/photo/aerial-view-of-muddy-river-through-rainforest-17025853/