River profiles
Long profile
A A section of the course of a river drawn from source to mouth. shows how the river changes over its course from its The place where a river starts in its upper course. (where it starts) to its The place where a river meets the sea. (where it meets the sea).
Upper course - in the upper course, where the river starts, there is often an upland area. The river's The particles of rock carried by a river. is comprised of large material in the upper course, as it hasn't been broken down by The 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 (or cross section)
A A cross-section of the valley and channel of a river. is a view of the A 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 When 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 it.
B - as the river flows into the middle course, there is some vertical erosion but more The 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.