The Course of a River
A river is fresh water flowing across the surface of the land, usually to the sea. It flows in a channel. The bottom of a river is called the bed, and the sides of a river are called banks.
There are three parts of a river, the upper course (The start of the river), the middle course (The middle part of the river) and the lower course (The end of the river).
All rivers start at the source. This is usually up in the hilly ground. This means that there is a steep gradient which causes fast flow. As the water is flowing faster, more erosion occurs. Erosion is when the water, as it is flowing, it wears away the land. This is why you find V-shaped valleys. Transportation is another process that happens due to the water flowing fast. Transportation is when the river carries along with its current, materials such as mud and pebbles which have been eroded. At this point pot holes can be formed. A pot hole is formed by pebbles swirling around on the river bed. This action erodes the river bed therefore forming a hole. Over time, these pot holes can join with other pot holes till eventually the whole river bed is deepened. In the upper course, waterfalls can be formed. They are formed when the river flows over the hard rock. Where the water flows over soft rock, it erodes the softer rock away. Over time, it gets more and more eroded due to the water flowing on top of it. This makes a cliff. At the bottom of the cliff some of the water splashes onto the cliff and makes a plunge pool. A plunge pool is made by the rocks which are being carried along with the river, after falling down the waterfall they thrash about and erode the softer rock. Eventually, the hard rock falls off and starts the whole process again. The river is mainly straight.