Coastal landscape systems and sources of sediment deposition Flashcards
(20 cards)
What is the definition of the ‘coast’?
The area where the land meets the sea, also known as the ‘shoreline’.
Why is it better to refer to the ‘coastal zone’ instead of the ‘coast’?
It encompasses the area between the landward limit of marine influence and the seaward limit of terrestrial influence.
What are the components of a coastal landscape system?
Inputs, processes, outputs, and energy.
What distinguishes open systems from closed systems in coastal landscapes?
Open systems interact with the surrounding environment, allowing inputs and outputs to pass in and out, while closed systems keep them within boundaries.
What is a sediment cell?
A stretch of shoreline where sediment is deposited and transported.
What are the factors that prevent sediment from moving outside the boundaries of a sediment cell?
- Headlands
- River outflow
- Human intervention
What can cause sediment to move outside the boundary of a sediment cell?
- Storm surges
- Sea level rise
What is a sediment budget in a coastal landscape system?
The difference between the inputs and outputs of sediment.
What does it mean if a sediment budget is in ‘dynamic equilibrium’?
Inputs and outputs of sediment vary seasonally, but the system balances over time.
What happens if the inputs of sediment are greater than the outputs?
The system is in surplus.
What leads to a coastal landscape system being ‘depleted’?
A long-term deficit in sediment budget.
What is the primary source of sediment supplied to coastal landscapes?
Terrestrial sources, particularly fluvial deposition by rivers.
What is an example of a submarine canyon formed by river flow?
The Congo Canyon, which is ~280km long and ~1.1km deep.
How does the Congo River differ from many other river systems?
It does not spread out as a large estuary on the coast, resulting in a higher flow rate.
What are two additional sources of sediment for coastal systems?
- Offshore sources
- Aeolian sources
What is an example of a coastal environment facing navigation difficulties?
The Outer Banks (USA), known as the ‘Graveyard of the Atlantic’.
In which environments is aeolian deposition a more significant source of sediment?
Deserts, such as the Sahara and Arabian Peninsula.
What human intervention can be taken when a coastal sediment budget is in deficit?
Beach nourishment, which adds sediment to maintain equilibrium.
What are common sources of sediment for beach nourishment?
- Offshore dredging
- Terrestrial sources
What could cause the sediment budget to be in deficit?
Slowed erosion rates due to resistant rock, reduced wave energy, coastal defenses, or human intervention.
