Coastal Systems Flashcards
PMT
What is the coastal system driven by?
Wave energy within the nearshore and foreshore zones
What processes shape the morphology of the coastal zone?
Erosion, weathering, transportation, and deposition
What are the main physical variables affecting coastal systems?
- Climate/weather patterns/seasons
- Wave type and strength
- Wind direction
- Fetch length and direction
- Tidal range/flow
- Currents
- Geology of coastline
- Availability of sediment
What are examples of human influences on coastal systems?
- Coastal engineering and management
- Groynes
- Sea walls
- Disruption of sediment supply
- Dredging
- River dams
- Cliff protection
- Blocking structures
- Jetties
- Harbour walls
How are waves generated?
By the surface of the sea exerting frictional drag on the wave
What type of waves are characterized by an oscillation pattern where water does not move forward?
Oscillation waves
What factors influence the height of a wave?
- Fetch
- Strength of the wind
- Duration of the wind
- Sea depth
What occurs during wave refraction?
Wave fronts slow, bend, and aim to break parallel to shore
What are the two types of waves that shape beaches?
- Constructive waves
- Destructive waves
What are the characteristics of constructive waves?
- Long wavelength
- Low height
- Strong swash
- Weak backwash
What are the characteristics of destructive waves?
- Short wavelength
- Steep wave faces
- High wave height
- Strong backwash
Fill in the blank: The movement of water up the beach is called _______.
swash
Fill in the blank: The movement of water down the beach is called _______.
backwash
What determines the beach morphology?
- Wave type
- Energy
- Sediment type
- Sea bed morphology
What is the tidal range?
The vertical distance between high tide and low tide
What phenomenon occurs when the Earth, Moon, and Sun align, causing an extra high tide?
Spring tide
What happens during neap tides?
The tidal range is lowest
What is a sediment cell?
A length of coastline and its associated nearshore area where sediment movement is largely self-contained
What are the key characteristics of sediment cells?
- Discreet and function separately
- Sediment is sourced, transferred, and stored within the cell
- Coarse sediments are not exchanged between cells
What is the sediment budget?
The amount of sediment available to the sediment cell
How can human activity disrupt sediment cells?
- Blocking sediment movement
- Reducing fluvial sediment input
- Preventing cliff falls
What role do groynes play in coastal management?
They trap sediment in areas important for beach protection
What happens when sediment budgets increase?
More deposition is likely
What is the impact of high-energy destructive waves during winter months?
They can lead to significant beach erosion
What are groynes used for in coastal management?
To trap sediment in areas where a beach is considered essential for protection, leisure, or economic prosperity.
How do river dams affect sediment supply to coastal systems?
They cut down on the amount of fluvial sediment entering the coastal system.
What is the South Downs sediment cell?
It occupies sub-cell 4d along the Sussex coast between Selsey Bill and Beachy Head.
What rivers contribute sediment to the South Downs sediment cell?
- River Ouse
- River Cuckmere
- River Adur
- River Arun
What is the tidal range and how does it affect sediment erosion in the South Downs sediment cell?
The tidal range increases from west to east, affecting the quantities of flints and sediment erosion.
Fill in the blank: The falling ebb tide flows to the _______.
west
What has happened to the beaches of Rottingdean, Saltdean, and Seaford?
They have become seriously depleted and have been artificially replenished.
What impact did the construction of the breakwater at Newhaven have?
It helped starve Seaford beach.
How much sediment may be contributed by wave cut platform erosion?
400m³ of sediment.
What is the estimated sediment loss around Beachy Head to Eastbourne?
Up to 5000m³ of gravel and sand.
True or False: Major stores of gravel at Birling Gap are being depleted.
True
What is a back eddy in coastal systems?
It deposits sediment to the south of Pagham Harbour.
What are the three main components of a sediment cell?
- Sources
- Transfers
- Sinks
How can human activity affect the equilibrium of a sediment cell?
By disrupting sediment supply and altering natural coastal processes.
Define the term ‘sediment cell’.
A distinct section of coastline where sediment is sourced, transported, and deposited.
What are the predicted effects of global warming on coastal systems?
Changes in tidal ranges, weather patterns, sediment supplies, and wave energy affecting coastal stability.
What happens when one part of the coastal system changes?
The whole system works harder to compensate for the change and achieve equilibrium.
