Coastal Systems and Landscapes

What are coastal systems?

areas where the land meets the sea, involving inputs, outputs, flows, and stores of sediment and energy

What is the main input in coastal systems?

sediment brought in by rivers, waves, and tides

What is the main output in coastal systems?

sediment washed out to sea or deposited along the coast

What is the definition of erosion within coastal systems?

the process whereby sediment is removed from a coastline

What is dynamic equilibrium in coastal systems?

a balance between sediment inputs and outputs that maintains the coastal system's stability

What is negative feedback in coastal systems?

a change that causes other changes, leading to a restoration of balance in the system

What is positive feedback in coastal systems?

a change that causes further changes, creating a new equilibrium

What is prevailing wind?

wind that consistently blows from the same direction, generating higher-energy waves

What factors affect wave height?

• wind speed

• fetch

What is fetch?

the maximum distance of sea that wind has blown over to generate waves

What are the characteristics of constructive waves?

• low frequency

• strong swash

• weak backwash

• deposit sediment

What are the characteristics of destructive waves?

• high

• steep

• high frequency

• weak swash

• strong backwash

What is the definition of tides?

the periodic rise and fall of the ocean surface caused by the gravitational pull of the Moon and the Sun

Define currents in coastal systems.

What is the definition of currents in coastal systems?

the general flow of water in one direction, affected by wind or variations in water temperature and salinity

What is a high-energy coast?

a coast that receives high inputs of energy, leading to high rates of erosion

What is a low-energy coast?

a coast that receives low inputs of energy, leading to higher deposition rates than erosion

What is a sediment budget?

the balance of sediment that enters and leaves the coastal system

What are sediment cells?

sections of coastline that are self-contained for the movement of sediment

What is coastal erosion?

the wearing away of the coastline due to wave action

What is mass movement?

the movement of material downhill due to gravity, often seen in coastal erosion processes

What is chemical weathering?

the breakdown of rock in situ by changing its chemical composition

What is salt weathering?

weathering caused when saline water evaporates, leaving salt crystals that exert pressure on rocks

What role does vegetation play in stabilising sand dunes?

plant roots trap sediments and help to accumulate more sand, forming stable dunes

What is beach nourishment?

the addition of sand or shingle to a beach to widen it and reduce erosion

What is managed retreat?

a coastal management strategy that allows the shoreline to move while minimising damage

What is a sea wall?

a hard engineering structure that reflects waves and prevents coastal erosion

What is a groyne?

a structure built at right angles to the shore to trap sediment from longshore drift

What are barrier islands?

long, narrow islands of sand or gravel running parallel to the shore, typically formed by rising sea levels

What forms when a spit connects two headlands?

a bar, which can create a lagoon behind it

What is a fjord?

a drowned glacial valley, characterised by steep sides and a shallow mouth, commonly found in places like Norway

What are rias?

flooded river valleys that result from sea level rise, characterised by wide, deep mouths

How does climate change contribute to sea level rise?

• melting ice sheets

• the thermal expansion of seawater as global temperatures rise

What impact can coastal management have on sediment flow?

hard engineering can disrupt sediment flow, potentially causing increased erosion down-drift

What is Integrated Coastal Zone Management (ICZM)?

a management strategy that considers all elements of the coastal system and their interactions

Why are some coastal management practices considered unsustainable?

• high costs

• environmental disruption

• negative impacts on neighbouring areas

What is biological weathering?

weathering caused by living organisms, such as plant roots growing into cracks in rocks

What is the role of tidal barrages?

prevent flooding and generate electricity by controlling water flow in estuaries

What is attrition?

the process whereby pieces of rock in the water smash against each other, breaking into smaller pieces

What are hydrodynamic processes?

processes driven by the movement of water, such as erosion and sediment transport along coastlines