Rivers - Natural Features

1. A river begins its journey at its source which is usually in the mountains or hills.

2. There are different types of sources, some rivers begin when water flows out of rocks.

3. Others start with small channels of water called rills which join together to make streams.

4. Some rivers have their source in a lake.

5. The river flows in a channel, the bottom of which is called the river bed, and the sides the river banks.

6. River banks can be formed from rocks, or, as the river slows down and flows through flatter land, from clay or soil.

7. A river has three courses from source to mouth, known as upper course, middle course and lower course.

8. The upper course of the river is in the hills and mountains and the river is fast-flowing.

9. The middle course is where the river becomes wider and deeper and meanders occur.

10. The lower course, where the river is at its deepest and widest, is where the river gets close to the sea and has its mouth.

11. The shape and course of the river alters due to erosion and deposition.

12. Erosion is the wearing away of the river bed, banks and channel due to the flow of the water and the rock that it is carrying.

13. Deposition is where the river drops materials it is carrying, known as sediments, as it slows.

14. Erosion can create features like waterfalls and rapids.

15. Pressure of water can cut V-shaped valleys, which get deeper and wider over time and become U-shaped.

16. A gorge is a narrow, deep, steep-sided valley with rocky sides, eroded by a river.

17. The river grows as more tributaries flow into it.

18. A tributary is a stream or river flowing into a larger river, the place where they join it is called a confluence.

19. A meander is an S-bend in the river formed by erosion.

20. These occur in the lower and middle courses when the water is slower-moving.

21. As more and more erosion occurs ox-bow lakes can form.

22. These are formed when the meander neck becomes very narrow and the river breaks through.

23. The flat land beside the river is known as the flood plain and is covered by water when the river floods.

24. The river mouth is where the river finishes its journey by flowing into the sea.

25. If a river has a wide mouth it is called an estuary.

26. Here the slow moving river drops its sediments, often forming sandbanks.

27. Deltas are formed where the rivers slow before meeting the sea.

28. Sediment is dropped causing river to spread, often in a triangle shape.

29. Some of the world’s greatest ports are found on estuaries.