lowland features Flashcards
what happens to erosion when the river flows over lowland instead of the highland
The river has more energy and a high volume of water. The gradient here is gentle and lateral (sideways) erosion has widened the river channel. The river channel has also deepened.
what happens when a rivers channel grows larger
A larger river channel means there is less friction, so the water flows faster.
examples of lowland features
meanders,oxbow lakes, flood plains and levees.
what is a meander
A meander is one of a series of regular sinuous curves, bends, loops, turns, or windings in the channel of a river
where in the river does the water travel fastest at
The fastest and most powerful water travels around the outside of the bend.
why does water travel fastest round the outside of the bend
due to the outside having decreased friction
What effect does the fast flowing water around the outside of the bend have on the landscape
It causes erosion through techniques such as hydraulic action and abrasion
what effect does the slow flowing water on the inside of the bend have on the landscape
On the inside of the bend the water does not have enough energy to carry the rocks and sediment meaning there is deposition
How are oxbow lakes formed
after the meanders have been exaggerated through erosion and deposition the water wants to find the path of least resistance so therefore it’ll erode across the meander and deposit across it creating a much straighter river with the old meander left disconnected
what are levees
Levees are naturally raised river banks that run parallel to the river.
formation of levees
When a river bursts its banks and floods, friction with the land reduces velocity and causes deposition of the sediment as the water has had a loss of energy. Heavy sediment is deposited closest to the river, and smaller sediment can be transported further away. With each successive flood, there is a build up of layers on the levees and they grow.
what is a floodplain
The floodplain is an area of flat land in the lower course of the river.
formation of a floodplain
Erosion removes anyinterlocking spurs, creating a wide, flat area on either side of the river. During a flood, material being carried by the river is deposited (as the river loses its speed and energy to transport material).
characteristics of a floodplain
Large flat area of land. Prone to flooding. Floodplains are made up of alluvium (silty soil) which is excellent for farming as it makes the soil fertile.
how are deltas formed
A delta forms when water loses its velocity and ability to carry its load (sediments) and deposits them at the bottom of the river. With time, the sediments build up, forming new land. It is key to know that not all rivers have Deltas.
