How Are Waterfalls Formed?

The Western Part of Guadeloupe, called Bass Terre is rich in beautiful waterfalls. They differentiate in shape and high. Some are great for jumping off the cliffs into the basin, but others too high to risk a leap. Their sound is soothing and can be used as a meditation background. Waterfalls are not only pretty to look at but also fullfill an ecological worth, which I try to look into in this blog post. But first we´ll answer the question: How Are Waterfalls Formed?

How do waterfalls form?

The National Geographic describes a waterfall as “a steep descent of a river or other body of water over a rocky ledge” ¹. If you have ever wondered why it never runs out of water: The river feeds the waterfall. That´s the whole magic. Waterfalls shape with the change of soft to hard rock in the river course. To encourage your imagination of soft rocks, examples are sandstone and limestone. For hard rock, you could name granite. ¹

So, what have soft and hard rocks to do with waterfalls? When the soft rock lying beneath the hard rock erodes it forms a step, over which the water flows. The stream cuts in more and more into the soft rock creating an undercut of the hard rock. As the soft rock dwindles the hard rock collapses under its weight. This process is repeated until we have the steep edge over which water flows. Voila, our waterfall. ^{1 2} You can see this process in the video below, so you can imagine the formation of waterfalls more vividly.

About the ecological worth of waterfalls

Waterfalls are not only important for attracting tourists and hiking freaks. As the site of the Murchison Falls in Uganda ³ indicates, waterfalls have a high intrinsic value. To begin with, waterfalls can function as water treatment plants. They purify water with their flow. This purification occurs when organic waste is recycled into nutrients through the degradation processes by bacteria. The floatage of water over rocks before it reaches lakes and rivers permits bacteria growth. Furthermore, the purification process enables oxygen-rich water that favours aquatic life and the nutrient flow helps plants to grow next to the river. ⁴

Conclusion

Back to our question of the beginning: How are waterfalls formed? Waterfalls form when hard rock is undercut by eroding soft rock in a river stream. As the soft rock dwindles an edge is formed, over which the water flows into a basin. Waterfalls purify water, enable an rich aquatic life and favour plant growth and the river bank.

In my next post, you will learn about the soothing effect of running water and why waterfalls relax us.

References:

1. National Geographic, s.a. Available at: https://education.nationalgeographic.org/resource/waterfall [1.11.2022].
2. howitworksmag, 2015. How Waterfalls form. Youtube. Available at: https://www.youtube.com/watch?v=6t2FllizRN4 [1.11.2022].
3. Murchison Falls National Park, s.a. Why WaterFalls Are Important. Available at:  https://www.murchisonfallsnationalpark.com/why-water-falls-are-important.html [30.20.2022].
4. Murchison Falls National Park, s.a. Why WaterFalls Are Important. Available at:  https://www.murchisonfallsnationalpark.com/why-water-falls-are-important.html [30.10.2022].