Coastal Landscape systems

Question 1

What is a system?

Answer 1

interrelated components (stores) and processes that connect to form a working unit.

Question 2

What do the 3 types of energy enable?

Answer 2

Enable geomorphic processes to shape the land.

Question 3

Where is material from?

Answer 3

sediment on beaches, the nearshore zone, estuaries

Question 4

What are the inputs into the system?

Answer 4

Energy (kinetic from wind/waves, thermal from sun) and material (marine deposition, weathering and mass movement). Potential from position of material on slopes

Question 5

What are the outputs of the system?

Answer 5

Material transferred to other systems, marine/wind erosion and evaporation.

Question 6

What are throughputs in a system?

Answer 6

Processes, stores (beach/nearshore sed accumulation) and flows (transfers, e.g. LSD).

Question 7

What is equilibrium?

Answer 7

When the systems inputs/outputs are equal.

Question 8

What is negative feedback?

Answer 8

it is dynamic equilibrium, when e is disturbed the system self regulates to produce its own response.

Question 9

What is a sediment cell?

Answer 9

Stretch of coastline and its nearshore area, within which the movement of coarse sed is largely self contained. But wind direction change/tidal currents means its not a closed system.

Question 10

Describe characteristics of a constructive wave:

Answer 10

low height/freq. and long wavelength. Breaks as spilling, strong swash up sloping beach. Swash energy exceeds backwash energy (swash uninterrupted).

Question 11

Describe characteristics of a destructive wave:

Answer 11

Shorter wavelengths and higher. Break as plunging, so little forward transfer of energy up steep beach. Backwash exceeds swash (swash slowed by friction of previous backwash due to short wavelength).

Question 12

How do winds influence a coastal system?

Answer 12

Frictional drag of wind over ocean surfaces generates wave energy (longer fetch/higher speed means more energy). Energy carries out erosion, transportation and deposition, all Aeolian processes.

Question 13

What energy does a wave possess?

Answer 13

Potential (position above wave trough) and Kinetic (motion of water in waves). Relationship between wave height and energy is non-linear.

Question 14

What are the 4 parts of a wave?

Answer 14

Crest (highest), Trough (lowest), Height (vertical distance between crest/trough), Length (horizontal distance).

Question 15

What are waves affected by?

Answer 15

Gradient of sea floor, irregularity of coast, wind (?)

Question 16

What is the difference between a swell and a storm wave?

Answer 16

Swell forms over open oceans, generated from a long distance, wave period of 20secs+, Storm waves are locally generated, higher with a shorter period/length.

Question 17

Describe a breaking wave:

Answer 17

In shallow water, the wave touches the seafloor and friction changes the speed/direction/shape of it.

Question 18

What are the three types of breaking waves?

Answer 18

Spilling (steep waves on gently sloping beaches, water spills forward), Plunging (moderately steep waves break onto steep beaches, water plunges vertically as crest curls over) and Surging (low angle on steep beaches, wave slides forward, may not actually break).

Question 19

What is the relationship between beach gradient and wave type?

Answer 19

High energy waves (winter) remove material from top of beach to offshore zone (reduced gradient), low energy (Summer) build up beach face, steeper gradient.

Question 20

What causes Longshore drift?

Answer 20

Once deposited, sed moved along the shoreline, it occurs when waves approach the coast at an angle (due to direction of dominant wind).

Question 21

How is sediment moved in LSD?

Answer 21

Waves break, swash carry particles diagonally up beach (wind direction), backwash moves it perpendicularly back down the beach. Sed also has attrition, tend to be smaller with increasing distance along the beach.

Question 22

Why does deposition take place?

Answer 22

Loss of energy/decreased velocity; when rate of sed accumulation exceeds removal, waves slow after breaking, during backwash when water percolates and in low energy environments (sheltered from wind/waves).

Question 23

Why do tidal ranges vary?

Answer 23

Enclosed seas such as the Med have a low range, so wave action is restricted to a narrow area of land where the coast is funnelled.

Question 24

What is lithology?

Answer 24

the physical/chemical composition of rocks.

Question 25

What is a concordant coastline?

Answer 25

Rock outcrops that are uniform/parallel to the coast, produce straight coastlines.

Question 26

What is a discordant coastline?

Answer 26

Rocks lie at right angles to the coast create a planform that is ‘uneven’, resistant rocks make headlands. weaker make bays.

Question 27

How are ocean currents created?

Answer 27

Earths rotation and movement of winds across a water surface.

Question 28

What is terrestrial sediment?

Answer 28

Rivers as sources of sed input into the sed budget, in some locations 80% of coastal sed is from rivers.

Question 29

How do humans try to maintain sediment equilibrium?

Answer 29

Beach nourishment, if you subtract sed lost from sed gained you determine if the budget is surplus, deficit or equilibrium.