River Processes and Features Flashcards
What is the source of the river?
The area in which a river begins.
What is the mouth of a river?
Where a river ends its journey flowing into the sea or a lake.
What is a tributary?
A smaller river that joins a larger river.
What is a confluence?
The point at which two rivers join.
What is a watershed?
The boundary between two drainage basins marked by a ridge of high land.
What is a drainage basin?
The area which is drained by a river and its tributaries.
What is drainage density?
The total length of all the streams in the basin divided by the total area of the basin.
What is weathering?
The breaking down of rock in situ.
What is the most common type of weathering (for rivers) and how does it work?
Freeze Thaw Weathering: The weathering of rocks by continual freezing and thawing of moisture in cracks.
What processes shape the valley sides of rivers?
Weathering and mass movement.
What are the 4 types of erosion and how do they work?
Hydraulic Action: the sheer force of the fast flowing water hits the river beds and banks, cracking and breaking them down.
Abrasion/Corrasion: small boulders and stones scratch the river banks and bed
Solution/corrosion:
Rivers travel over dissolving rocks such as chalk and limestone.
Attrition:
Affects a river’s load. Stones collide with each other, smoothing and rounding each other and getting smaller.
What are the two types of erosion in rivers?
Vertical Erosion: downward erosion of a sea bed
Lateral Erosion:
Sideways erosion of the river banks
What factors affect the rate of erosion?
- Gradient
- Amount of bedload
- Human factors
- Building concrete riverbeds
- Velocity
- Geology
What are the four types of transportation?
Suspension: fine, light material is carried along by the river.
Traction: large boulders and rocks are rolled along the river bed.
Solution: minerals are dissolved in the water. This is a chemical change.
Saltation: Small pebbles and stones are bounced along the river bed.
What is the Hjulstrom Curve?
A graph showing the diameters (sizes) of particles that are transported, eroded and deposited at different velocities.
