How does the cross profile 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).
How does a river’s cross profile change?
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 does the valley cross section change downstream?
In the upper course, the valley cross-profile is narrow and steep-sided. The river takes up most of the valley floor. In the middle course, the valley becomes wider due to lateral erosion.
What is the cross profile in geography?
A cross profile shows a cross-section of a river’s channel and valley at a certain point along the river’s course. As a result, the channels are narrow and shallow and may contain large boulders and angular fragments eroded and weathered from the steep valley sides. …
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 does a river change from upper to lower course?
The river channel gets deeper and wider as the bed and banks are eroded. The sediment load of the river gets smaller in size. Small meanders and a small floodplain can be found in this part of the river. Lower course – the final course of the river is where the land is a lot flatter.
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.
Why does the cross sectional area increase downstream?
It’s well known that rivers increase in size as they transport water from their source in their headwaters to the mouth. The river channel becomes wider and deeper and as a result its cross-sectional area increases. As we track the river downstream bedload becomes much smaller and smoother.
Why does the cross profile of a river valley change downstream?
As the river flows downstream it is joined by tributaries, increasing the volume of water, velocity and therefore its erosive power. This enables it to cut a deeper channel as it flows downstream. Downstream, the channel becomes wider as the gradient becomes more gentle leading to less vertical erosion.
How does gradient change from upstream to downstream?
Gradient (the slope of the land) decreases as rivers flow because the river meanders across the land rather than erode into it and follow a straight path as it does in the source. This means it covers a decrease in height over a longer distance the further downstream you get.
What is the cross sectional profile of river?
What is a 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 do you draw a cross profile in geography?
- How to Draw a Cross-Section of a Map.
- Take a thin strip of paper and place it along the transect line on the map.
- On a piece of graph paper, draw the horizontal axis of your graph exactly the same length as the transect A-B.
- Draw two vertical axes using a suitable scale.
What does a cross profile of a river show?
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.
What is the difference between a channel cross profile and valley cross-profile?
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 and why does a channel cross-profile change downstream? How does the cross-profile of a river change? There are three main sections along the long profile of a river.
What is the difference between lower course and cross profile?
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. A cross profile shows a cross-section of a river’s channel and valley at a certain point along the river’s course.
What is a long profile of a river?
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. Upper course – in the upper…