Drainage Basins Flashcards
What is a drainage basin?
An area of land drained by a river and its tributaries
A drainage basin collects precipitation and channels it into a river system.
What is the boundary of a drainage basin called?
Watershed
A watershed separates one drainage basin from another.
What typically forms a watershed?
A range of hills or mountains
The high ground of a watershed directs precipitation into specific drainage basins.
True or False: Precipitation falling beyond the watershed will be part of the same drainage basin.
False
Precipitation beyond the watershed enters a different drainage basin.
Fill in the blank: The area of land drained by a river and its tributaries is called a _______.
drainage basin
This is a crucial concept in understanding river systems.
What role does a watershed play in relation to drainage basins?
It separates one drainage basin from another
Watersheds are essential for managing water flow and drainage.
What is the source of a river?
The area in which a river begins.
The source is often located in highland areas or mountains.
What is the mouth of a river?
Where a river ends its journey flowing into the sea or lake.
The mouth can create estuaries or deltas.
Define tributary.
A small river that joins a larger river.
Tributaries contribute water and sediment to the main river.
What is confluence?
The point at which two rivers join.
Confluences can create larger and more powerful rivers.
What is a watershed?
The boundary between two drainage basins marked by a ridge of highland.
Watersheds are crucial for determining the flow of water in a region.
Define drainage basin.
The area which is drained by a river and its tributaries.
Drainage basins are important for water management and ecosystem health.
What are the four different types of river erosion?
- Lateral Erosion
- Vertical Erosion
- Hydraulic Action
- Abrasion
These processes work together to shape the landscape through erosion.
What is the primary role of rivers in the landscape?
Rivers erode, transport, and deposit material.
This process significantly alters the land over time.
What occurs during vertical erosion?
Vertical erosion occurs in the upper part of a river.
This typically deepens the riverbed.
Where does lateral erosion occur?
Lateral erosion occurs in the middle and lower stages of a river.
This process widens the river.
Define hydraulic action in the context of river erosion.
Hydraulic action is the force of the water hitting against the bed and banks of the river.
This force can cause pressure and lead to erosion.
What is abrasion in river processes?
Abrasion is the grinding of rock fragments carried by the river against the bed and banks.
This process contributes to both lateral and vertical erosion.
Fill in the blank: _______ is the process where water forces its way into cracks in the riverbed.
Hydraulic Action
This process can lead to the breakdown of riverbanks.
True or False: Rivers only erode material in their upper stages.
False
Rivers erode material through both vertical and lateral processes across different stages.
What is attrition in the context of river transport?
Attrition is when rocks being transported by the river hit/smash together and break into smaller, smoother, and rounder particles.
Define solution in terms of river erosion.
Solution is a form of chemical erosion where chemicals in the river water dissolve minerals in the rocks in the bed and bank, carrying them away in solution.
What types of rocks are commonly affected by solution erosion?
Limestone and chalk.
True or False: Attrition results in larger and rougher particles.
False
Fill in the blank: __________ is a form of chemical erosion that carries minerals away in solution.
[solution]
What is transportation in the context of river processes?
The movement of material
What do rivers need to transport material?
Energy
How does the speed of a river affect its energy for transportation?
When a river moves quickly, it has more energy for transportation
List the four different ways rivers transport their load.
- Traction
- Saltation
- Suspension
- Solution
What factors determine the type of transport that can take place in a river?
- The size of the sediment
- The amount of energy available
Define traction in river transportation.
The heaviest material (large rocks) is rolled along the river bed
What type of transportation requires the largest amount of energy?
Traction
Describe saltation in river transportation.
Medium sized load is bounced along the river bed in a leap-frog motion
What is suspension in the context of river transport?
Small particles (clay and silt sized) are carried within the water, above the river bed, in turbulent flow
What type of particles are carried in suspension?
Small particles like clay and silt
Explain solution in river transportation.
Rocks that have been dissolved by the water are carried in solution
Which type of river transport requires the least amount of energy?
Solution
What does deposition in river processes refer to?
The process where material carried in the river’s flow is dropped.
When does deposition occur in river processes?
When there is no longer sufficient energy to transport material.
What type of material is dropped first during deposition?
The largest material, as it requires the most energy to be transported.
List one condition under which deposition can occur.
- Shallow water
- Decreased volume of water (e.g., heat wave)
- Near the mouth of a river
- During river floods onto the floodplain
- Sudden increase in load (e.g., after a landslide)
True or False: Deposition can only occur when the river is flowing at high energy.
False
