Moving from the upper course of a river to the lower course effects the rates of erosion, transportation and deposition change. This results in the development of large and small scale landforms.
A long profile shows how the river changes over its course from its sourceThe place where a river starts in its upper course. (where it starts) to its mouthThe place where a river meets the sea. (where it meets the sea).
Upper course – this is where the river starts and is usually 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 – the final course of the river is where 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. is a view of the valleyA low area of land between hills or mountains, typically with a river flowing through it from one side to another.
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 – 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 and greater influence of deposition, with only some lateral erosion. The channel is at its widest and deepest.