So, have you ever wondered how that part of a river got there? Or how that enormous, crashing waterfall just happened to come into existance? Well, in this series of blogs, I'll explain the wonders of a river. Enjoy!

Okay. So first, let's imagine ourselves a river. You know, those long winding things? No, not those. -.-'. Anyway, this river is flowing happily when suddenly, it reaches a cliff. The river drops down the cliff and carries on it's journey. This is known as a Waterfall. Here is a DSiPaint drawing of the frontal view of a river:



Moving swiftly on. Now, let's turn our waterfall around so that we are looking at it from the side. We'll just cut into the ground to get a closer look. This is called a Cross Section.



No, that's not a cross section. Noob. Here it is!



Now, looking at the diagram, we assume that the darker layer at the top is Hard rock and the lighter layer at the bottom is Soft rock. Got that? Good. Now, over time, the water falling down pushes the ground below the river (the riverbed) and whacks it with rocks (load) so that slowly, but surely, the riverbed is eroded. Also, as the water crashes downwards, it erodes the back of the waterfall too, leaving a big space. So, we'll now travel a long time into the future... and here's what our waterfall looks like now:



You can see in the diagram that a plunge pool has been eroded into existance below the waterfall. You can also see that the hard rock is hanging off the edge of the gap and is under a lot of pressure. Uh oh. Now, we fast-forward into the future again... and here's what our waterfall looks like now:



Look! The hard rock ledge has fallen, and now the first part of a gorge has formed. Now the cycle starts again, and will continue for years to come. Ah.

Glossary:

Erosion: The wearing away of the Earth's surface.
Gorge: A narrow valley with steep sides, formed by a waterfall moving backwards.