Why does a river curve and twist instead of running straight?

There are many bodies of water in our planet, wherein its surface takes up 71 percent of water, and among these bodies of water, includes the river.

Rivers are usually long watercourses, flowing with fresh water towards oceans, seas, lakes, as well as another river. There are plenty of rivers all around the globe with various sizes and appearances. For the record, we can find the world’s largest river, the Nile River, in eastern Africa, spanning for roughly 6,650 kilometers – or 4,135 miles. 

Over the years, rivers play an essential part in the survival and civilization of humans, mainly during ancient times. Thousands of years ago, people often live close to rivers since it is their source of freshwater.

Interestingly, the size and appearance of rivers also change over the years. Their shape and structure probably don’t look the same as it was thousands of years ago. This change in appearance is a result of various water activity, environment, weather, and other factors. That is why we can notice our rivers are flowing in different directions, and not all of them are running straight – some of them are curved or twisted.

In this article, we are going to look into interesting facts about rivers and answer our question – why does a river curve instead of running straight?

Why are some rivers running in a curved path?

The structure of rivers holds some fascinating designs, and just by looking at it, we can appreciate its beautiful scenery. Usually, a river runs in a straight path. However, as mentioned earlier, rivers sometimes create curves due to various reasons – mainly because of its surrounding elements.

These curved rivers, also known as meandering rivers, are a result of the swinging of stream to its sides. If we look at a river, it may appear as shallow and calm. However, that is not always the case since the appearance of rivers could be deceiving. Little do we know that there is a lot of activity going on beneath the river. Most of the time, these activities are strong currents running down the stream, slamming to the sides of the river banks. 

When a fast flow of water hits a riverbank, it gradually erodes its material – including sand, soil, and dirt. Because of this, one side of the stream will have a weak and slow current, which is not enough to sweep and carry sediments from the river banks.

This continuous motion in the river will cause the side with the strong current to slowly create a new path. While the other side of the stream, with the weak flow of water, will follow the newly opened path, which in turn will cause its side to lose water movement. Without water movement, the soil will dry up, and it will eventually create a new landmass.

As for the new path, the strong water current will gain momentum as it moves in the curve path and continues to have a fast flow until it slams to the opposite side of the new route. This intense water activity will cause the other side to create a new curved path, and as we can notice, this process continues as long as there is a strong current. This process explains why there are long rivers with several curves and why it is nearly impossible for rivers to run in a straight line – there is always a curve.

Over the years, the structure of rivers continues to change. If there are already curves and bend on the river, it will become wider eventually, as the fast flow of water continues to erode the material on the side, making way for new routes and landmass. However, once the curve paths on a river get so wide, they will bump into each other, which will cause its boundary to break, creating a new straight route for the water to flow. As the water flows in the straight path, it will dry up the bends on the opposite side, which will make it lose its water movement. Now what’s left is the straight path and an isolated curve, called the oxbow lake. 

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