UNIT 1C - RIVER PROCESSES (Drainage basins (Channel - this is where the…
UNIT 1C - RIVER PROCESSES
- A cross profile shows a cross-section of a river’s channel and valley at a certain point along the river’s course.
C - in the lower course there is a lot less erosion, with only some lateral erosion. The channel is at its widest and deepest.
B – as the river flows into the middle course, there is some vertical erosion but more lateral erosion. The channel is wider and deeper as a result.
A - as the river flows downhill there is an increase in vertical erosion. The channel is shallow and narrow because there is not a lot of water in the channel.
- A long profile is a line representing the river from its source (where it starts) to its mouth (where it meets the sea). It shows how the river changes over its course.
- in the lower course, the land is a lot flatter. The river's load is fine sediment, as erosion has broken down the rocks.
- in the upper course, where the river starts, there is often an upland area. The river's load is large in the upper course, as it hasn't been broken down by erosion yet.
- this is where the river flows
- a small river or stream that joins a larger river
- the point at which two rivers meet
- where a river meets the sea
- where a river begins
- the area of high land forming the edge of a river basin
A drainage basin is the area of land around the river that is drained by the river and its tributaries.
A river's water can fluctuate over time. Understanding the hydrological cycle is useful in order to understand how and why the amount of water fluctuates.
- When the river loses energy, it drops any of the material it has been carrying. This is known as deposition.
when the volume of the water decreases
at the end of the river's journey, at the river's mouth
- The river picks up sediment and carries it downstream in different ways.
- the transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.
- lighter sediment is suspended (carried) within the water, most commonly near the mouth of the river.
- pebbles are bounced along the river bed, most commonly near the source.
- large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the load is larger.
- Erosion is the process that wears away the river bed and banks. Erosion also breaks up the rocks that are carried by the river.
- When the water dissolves certain types of rocks, eg limestone.
- When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.
- When pebbles grind along the river bank and bed in a sand-papering effect.
- This is the sheer power of the water as it smashes against the river banks. Air becomes trapped in the cracks of the river bank and bed, and causes the rock to break apart.