Theme 1: Landscapes and Physical Processes Flashcards
Define a cross-profile.
A cross-profile is a cross-section of the valley and channel of a river.
Define erosion.
The wearing away of pieces of rock, soil or other solid materials.
Define the hydrological cycle.
The continual movement of water between the rivers, oceans, atmosphere and land.
Define lateral erosion.
The wearing away of the landscape when a river erodes sideways.
Define ‘load’.
The particles of rock carried by a river.
Define the mouth and the source!
m= the place where a river meets the sea. s= the place where a river starts in its upper course.
Define transportation!
To move objects or people from one place to another.
Define tributary.
A small river that joins the main river channel.
Define valley and because that’s fairly simple, also define vertical erosion :)
Valley= A low area of land between hills or mountains, typically with a river flowing through it
Vertical Erosion= 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.
Define long profile.
A section of the course of a river drawn from source to mouth.
Define confluence and watershed
Confluence= the point where two rivers meet. Watershed= the area of high land forming the edge of a river basin.
What are some things you know about the upper course?
- has a large load
- start of the river
- often in upland areas
- often downhill, so there’s more vertical erosion
- channel is narrow and shallow
- not much water at this stage
What are some things you know about the middle course?
- some vertical erosion but more lateral erosion
- the channel is wider and deeper
- more water than the upper course
What are some things you know about the lower course?
- flatter land
- load is fine sediment
- little erosion, mostly lateral
- greater influence of deposition
- channel is at its widest and deepest
Types of River Erosion 1: Hydraulic Action
This is the sheer power of the water as it smashes against the river banks. Air becomes trapped in the cracks in the rock of the river bank and bed, and causes the rock to break apart.
Types of River Erosion 2: Abrasion
When pebbles are picked up by the flowing water and smash against the river bank and bed, wearing it away.
Types of River Erosion 3: Attrition
When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.
Types of River Erosion 4: Solution
When the water dissolves certain types of rock, eg limestone.
Types of River Transportation 1: Traction
Large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the load is larger.
Types of River Transportation 2: Saltation
Pebbles are bounced along the river bed, most commonly near the source.
Types of River Transportation 3: Solution
The transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.
Types of River Transportation 4: Suspension
Lighter sediment is suspended (carried) within the water, most commonly near the mouth of the river.
Define deposition.
As the river loses energy, it ‘deposits’ the material it has been carrying.
When a wave transports sediment/ sand up the beach but has not got enough energy to bring it back, so leaves it there.
What are the factors that lead to deposition?
- shallow water
- at the end of the river’s journey, or at its mouth
- when the volume of water decreases