How does the cross profile of a river change downstream?
The cross profile of a river shows how the width and depth of the river valley and channel change as you travel downstream. Near the source of a river there is more vertical erosion as the river flows downhill, using its energy to overcome friction (A). The sediment in the river creates turbulence and friction.
How and why does the long profile of a river change?
The long profile of a river is a way of displaying the channel slope (gradient) of a river along its entire length. As a river flows downstream from its source the profile changes due to the interaction of the process of erosion, transportation and deposition.
How does a rivers long profile change?
The long profile of a river shows changes in the height (altitude) of the course of a river from its source to its mouth. A long profile is usually concave and the slope becomes more gentle towards the mouth of the river. Long profiles usually have irregularities such as waterfalls or lakes.
Why do channel characteristics of a cross profile change downstream?
Channel characteristics affect both velocity and discharge As you move downstream from a river’s source to it’s mouth, velocity (kinetic energy) and discharge increase. Discharge increases due to tributaries (smaller rivers/streams) joining the main channel and further inputs from surface runoff as you go downstream.
How do you describe the cross-section of a river?
A cross profile shows a cross-section of a river’s channel and valley at a certain point along the river’s course. 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. The channel is at its widest and deepest.
How do you draw a cross-section of a river?
To draw the shape of a river valley, the line is best drawn to connect the highest point on either side of the valley, at right-angles to the river. 2 Put the straight edge of a piece of scrap paper along your cross-section line. Mark the beginning and end of the cross-section, and write down the grid references.
What are the 3 sections in the long profile of a river?
There are three main sections along the long profile of a river. These are the upper, middle and lower course. Each has its own channel cross-profile features.
What’s the profile of a river?
river profile The slope along the bed of a river, expressed as a graph of distance-from-source against height. In detail it is typically compound, with the profiles of individual segments reflecting the local rock types.
How does a Rivers long profile and cross profile vary over its course?
The cross profile of a river changes as it moves from the upper to lower course as a result of changes in the river’s energy and the processes that the river carries out. In the upper course, the valley and channel are narrow and deep as a result of the large amount of vertical erosion and little lateral erosion.
How is a river cross profile different from a valley cross profile?
River cross profiles show you a cross-section, taken sideways, of a river’s channel and/or valley at certain points in the river’s course. A channel cross-profile only includes the river whereas a valley cross-profile includes the channel, the valley floor and the sides of the valley.
How does the shape of a cross river change?
The shape of the long river profile and the cross river profile changes. Near the source of a river there is more vertical erosion as the river flows downhill, using its energy to overcome friction (A).
How does the profile of a river change?
There is generally a steep reduction in the height of a river from its source to a more gradual reduction in height further downstream to the mouth of the river. Traced on a diagram, the profile would have a concave appearance.
Why are long profiles of a river rare?
However, long profiles are rare as there are a number of geographical factors that can interfere with this. For example, the land can be uplifted along the course of the river and can be affected by different bands of hard and soft rock crossing the path of the river. Also the sea level can change. How does a river change downstream?