Topic 2.1 - Introduction to coasts

What is a coast?

A narrow strip of shoreline that separates land from sea that is shaped and influenced by both natural and human activity within a powerful system

What type of environment is a coast?

A constantly changing dynamic environment

Why is a coast a dynamic environment?

It is where land, sea and air meet

What is the main thing the coast is affected by that is not natural, and why?

Human activity because over 4 billion people live at the coast worldwide

Why do coasts vary from place to place?

Due to factors that affect and shape coasts varying from place to place

What type of zone is a coast?

A narrow coastal zone that extends between the inland limit of coastal influence and the seaward limit of lands influence

What is an example of the inland limit of coastal influence?

Where storm waves hit

What is meant by the inland limit of coastal influence?

The furthest point inland where coastal processes can have a measurable impact

What is meant by the seaward limit of lands influence?

The furthest point out to sea where processes originating from the land have a measurable impact on marine environments or coastal systems

What is a narrow coastal zone?

A relatively thin strip of land adjacent to the sea, typically constrained by human or physical features that limit width

What are the 4 areas of the coastal zone? (Starting from the cliff)

1. Backshore

2. Foreshore

3. Nearshore

4. Offshore

What should I know about the backshore in terms of tide?

It is beyond high tide

What should I know about foreshore in terms of tide?

Expanded at high tide and is the most active and dynamic part of the coastline

What is the range of high tide on the coastal zone?

Starts at the end of the back shore zone (beginning of foreshore zone) (from the point at which the beach meets the separating line of the beginning of the foreshore zone) through the nearshore zone and into the offshore zone

What is the range of low tide on the coastal zone?

End of the foreshore zone (beginning of nearshore zone) (from the point at which the beach meets the separating line of the beginning of the nearshore zone) through offshore

What is a system?

A set of interrelated stores and processes that are connected together to form a working unit

What is the equation that symbolises a systems flow?

Inputs of energy and matter > Processes and stores > Outputs of energy and matter

What are the 3 places where energy may come from in a tidal system?

1. Tidal energy

2. Wind (Makes waves)

3. Thermal energy from the sun

What are the 2 types of systems?

An open and closed system

What is an open system?

Where matter and energy can both cross the boundary to and from the surrounding environment allowing for a flow in and out

What is a closed system?

Where only energy can transfer across the system boundary and flow in and out but matter cannot leave and cannot be added and is cycled within the system.

What is an example of a closed system?

The water cycle

What is an example of an open system and why?

A coastal system because sediment can move in and out

What is the coastal system driven by?

Flows of energy within the nearshore and foreshore zones which allows for earth shaping measures to occur, known as geomorphic processes

What are the 5 geomorphic processes?

1. Deposition

2. Mass movement

3. Erosion

4. Weathering

5. Transportation

What is deposition?

Waves deposit and drop their sediment

What is mass movement?

When material collapses under gravity causing a downhill movement

Which processes are both geomorphic and subaerial processes?(What do they not involve?)

Mass movement and weathering which both do not involve waves

Which geomorphic processes involve waves?

Deposition, Erosion and Transportation

What are subaerial processes?

Land based natural processes that alter coastline shapes, weaken cliffs and accelerate coastal recession

What are the 4 different flows of energy?

1. Solar energy

2. Kinetic energy

3. GPE

4. Geothermal energy

What does GPE stand for?

Gravitational potential energy

What is solar energy?

A renewable energy source from the suns radiation

What is kinetic energy?

Energy possessed by an object due to motion

What is GPE?

Energy stored in an object due to how far away it is from the ground due to the gravity acting on it based on how high it is

What is geothermal energy?

Renewable energy derived from the heat stored within the earths interior

What are examples of energy inputs that operate over long time scales?

Geothermal energy such as the convergence of plates along the west coast of South America

What are examples of energy inputs that operate over short time scales?

Wind can be generated and die in a matter of hours and gravity can last a matter of seconds

What does converge mean?

2 or more tectonic plates collide with each other

How is sediment stored in the coastal landform??

In depositional landforms

What is a depositional landform?

Land features created when eroded material is laid down by natural processes like water, wind or ice, because these transporting agents lose energy and can no longer carry the sediment load

What are the 7 depositional landforms?

1. Beach

2. Offshore bar (bottom of the beach)

3. Tombolo

4. Spit

5. Sand dune

6. Salt marsh

7. Bar

What are coastal systems state of equilibrium?

They are rarely in a state of equilibrium but are constantly moving towards it which means that are in a state of dynamic equilibrium

What processes shape and move sediment?

Geomorphic processes between stores, like transportation

What type of system do coastal systems have?

Complex dynamic interlined systems as change in one part of a system will impact other parts of a system, they adapt based on sediment supply nd wave energy levels

What are the 5 inputs of matter?

1. Longshore drift

2. Sand dunes

3. Offshore bars

4. Cliff erosion

5. River discharge

What usually happens to energy once it has gone through geomorphic processes?

The energy is used up during these processes

What are the 3 outputs of matter?

• Longshore drift

• Sand dunes

• Offshore zones