River profiles
Long profile
A long profileA section of the course of a river drawn from source to mouth. 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.
- Upper course - in the upper course, where the river starts, there is often an upland area. The river's loadThe particles of rock carried by a river. is large in the upper course, as it hasn't been broken down by erosionThe wearing away of pieces of rock, soil or other solid materials. yet.
- Lower 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.
Cross profile
A cross profileA cross-section of the valley and channel of a river. shows a cross-section of a erosionThe wearing away of pieces of rock, soil or other solid materials. and valleyA low area of land between hills or mountains, typically with a river flowing through it at a certain point along the river鈥檚 course.
- A - as the river flows downhill there is an increase in vertical erosionWhen the land is eroded or worn away in a downwards direction, eg a river that is high up will erode vertically because gravity pulls the water downwards.. The channel is shallow and narrow because there is not a lot of water in the channel.
- B 鈥 as the river flows into the middle course, there is some vertical erosion but more lateral erosionThe wearing away of the landscape when a river erodes sideways.. The channel is wider and deeper as a result.
- C - in the lower course there is a lot less erosion, with only some lateral erosion. The channel is at its widest and deepest.