2 - Coasts (`System, wind, waves)

Question 1

Is the coastal environment an open or closed system?

Answer 1

An open system.

Question 2

The coast is the ____ between land and sea.

Answer 2

Boundary

Question 3

What are the inputs in the coastal system?

Answer 3

Energy (from waves, winds, tides and sea currents)
Sediment
Precipitation

Question 4

What are the stores/components in the coastal system?

Answer 4

Erosional landforms (cave, stack, stump, arch, wave-cut platform)
Depositional landforms (beaches, sand dunes)

Question 5

What are the flows/transfers in the coastal system?

Answer 5

Wind blown sand
Sub-aerial processes
Mass movement
Longshore drift

Question 6

What are the outputs of a coastal system?

Answer 6

Dissipation of wave energy
Movement of material about the tidal range
Sediment removed offshore

Question 7

Give an example of positive feedback in the coastal system.

Answer 7

Beach starts to form…waves slow down…waves loose energy…more sediment is deposited…beach grows!

Question 8

Give an example of negative feedback in the coastal system.

Answer 8

Beach is eroded…cliff is exposed to wave attack…sediment eroded is deposited…cliff grows again.

Question 9

Name the 4 coastal zones.

Answer 9

Backshore
Foreshore
Nearshore
Offshore

Question 10

Name the 4 sources of energy on coasts.

Answer 10

Wind
Waves
Currents
Tides

Question 11

Wind is the most important ___ in the coastal system; it is the primary source of energy for all the other systems.

Answer 11

Input

Question 12

How does wave energy link to wind?

Answer 12

Wave energy depends on the strength of the wind, the length of time its blowing and the fetch.

Question 13

How are waves formed?

Answer 13

Waves are created by the transfer of energy from the wind blowing over the sea surface.

Question 13

Define prevailing wind.

Answer 13

The usual direction of the wind. It influences the direction that waves approach the coastline, and the direction of the transport of material on the coastal zone.

Question 13

Define fetch.

Answer 13

The distance of open water over which a wind blows, uninterrupted by major land obstacles. Generally the longer the fetch, the more energy waves will have.

Question 13

Wind is an agent of ___. It picks up and removes ___, and uses it to ___ other ___.

Answer 13

Erosion, sediment, erode, features.

Question 14

As waves approach ___, the bottom of the wave is affected by ___ and slows down causing the wave to ___ and wave height ___ until it ___.

Answer 14

Shore, friction, slope, increases, breaks.

Question 15

Describe a constructive wave.

Answer 15

Low wave height (under 1m)
Long wavelength
Low wave frequency (8-10 per minute)
General movement = spilling
Swash is strong = deposition!
Backwash is weak
Associated with berms

Question 16

Describe a destructive wave.

Answer 16

High wave height (over 1m)
Short wavelength
High wave frequency (10-14 per minute)
General movement = plunging
Swash is weak
Backwash is strong = erosion
Associated with a storm beach

Question 17

Explain wave refraction.

Answer 17

Section of wave in front of a headland will slow down due the the shallow water. The part of the wave in deeper water will move faster causing the wave to bend.
Wave energy is concentrated at the headland = erosion.
Wave energy is weak at the bay = deposition.
This can result in longshore currents.