Coasts

Question 1

Backshore definition

Answer 1

Is the area between the high water mark and the landward limit of marine activity

Question 2

Foreshore

Answer 2

This is the area lying between the high water mark and the low water mark and is often seen as the most important area for marine activity

Question 3

In shore

Answer 3

the area between the low water mark and the point where the waves cease to have any influence on the land around them

Question 4

Offshore

Answer 4

the area between the low watermark and the point where waves cease to have any influence on the land around them

Question 5

Nearshore

Answer 5

the zone extending seaward from the low water mark, it defines the area influenced by the nearshore or longshore currents.

Question 6

How can coastal landscapes be viewed as systems?

Answer 6

within a coastal landscape these three components ( Inputs, Processes and Outputs) store and transfer energy and material on time scales that can vary from a few days to millennia.

Question 7

Inputs in coastal systems

Answer 7

• Kinetic energy from the waves and wind
• Thermal energy from the sun
• Potential energy from material on the slopes
• Material from marine erosion/deposition
• Material from weathering and mass movements from cliffs

Question 8

Processes in a coastal system

Answer 8

• Accumulation of material on beach and nearshore sediment
• flows of material through transportation methods and longshore drift

Question 9

Outputs in a coastal system

Answer 9

• Evaporation
• Marine erosion
• Wind erosion
• Landforms
• Transfer of material to another system ( Sediment cell )

Question 10

Sediment cell definition

Answer 10

A sediment cell is a stretch of coastline and its associated nearshore area within which the movement of coarse material, sand and shingle is largely self contained.

Question 11

Sediment cell is a ….

Answer 11

closed system ( Material is not transfered from one cell to the other … except in high tides or storm surges. the material therefore stays in the sediment cell and is recirculated around)

Question 12

Dynamic equilibrium definition

Answer 12

Dynamic equilibrium in a sediment cell is where input and outputs of sediment are in a constant state of change but ​remain in balance​.

The dynamic equilibrium may be upset in the ​long term​ by ​human interventions​, or in the ​short term​it may be interrupted by ​natural variations​.

Question 13

Wind’s influence on coastal landscapes

Answer 13

• Also known as aeolian processes
• the source of energy for coastal erosino and sediment transport is through wave action
• wave action is generated by the frictional drag or winds across the oceans surface
• the higher the wind speed the faster the erosion rate as the waves have more energy and velocity
• Onshore winds ( Towards the land) are effective at driving waves towards the land
• wind is a moving force which results in erosion transportation and deposition processes.

Question 14

Wave’s influence on coastal systems

Answer 14

• A wave possess the potential energy from the postition of the wave trough, as well as kinetic energy from the motion of the water

Question 15

swash definition

Answer 15

as the wave moves up the beach

Question 16

back wash definition

Answer 16

as the wave moves down the beach ( drawn down)

Question 17

Breaking waves - Spilling waves

Answer 17

steep waves breaking onto gently sloping beaches water spills gently forward as the wave breaks

Question 18

Breaking waves - Plunging waves

Answer 18

Moderatley steep waves breaking onto steep beaches water plunges vertically downwards as crest curls over

Question 19

Breaking waves - Surging

Answer 19

Low angle waves breaking onto steep beaches the wave slides forward and may not actually break

Question 20

Constructive waves

Answer 20

Low in height, long wavelength, low frequency.
- Usually break as spilling waves with strong swash and weak backwash

Question 21

Destructive waves

Answer 21

Greater in height, shorter wave length, higher frequency
- usually break as plunging waves on steep beaches slow swash strong backwash removes sediment from beaches

Question 22

Tides Definition

Answer 22

Tides are caused by the gravitational pull of the moon and to a lesser extent the sun

Question 23

How do tides affect the coastal system?

Answer 23

Tides are an important factor in considering coastal processes as their interation with the coastal environment to a large extent determines the location of many coastal landforms.

• weak tidal currents and small tidal range determine the shape and extent of river details as well as the size of beach profiles. The extent of the tidal range will also influence the rates of erosion found at cliffs

Question 24

How does Lithology influence the coastal system?

Answer 24

• Lithology is the physical and chemical composition of rock
• Some rock types such as clay have a weak lithology with little resistance to erosion, weathering and mass movements.
• This is because the bonds between particles that may make up the rock are weak and easy to break apart

Question 25

How does structure influence the coastal system?

Answer 25

The rock strata needs to be stable in order to withstand erosion,mass movement and weathering. Without a stable rock strata and structure erosion rates will increase in turn also increasing sediment budget.