Georgraphy Theme 2 - Coastal Processes and landforms

Question 1

Coastal erosion - 4 types

Answer 1

Remember CASH - same as rivers
- Corrasion = abrasion caused by rubbing together of material and then wearing down and smoothing

• Attrition = erosion caused by waves where rocks bump together and break up
• solution = erosion where corrosion from salts and other acids in seawater dissolve the rocks and then transport them along.
• hydraulic action = force of waves compressing air in cracks of a cliff

Question 2

Destructive Waves

Answer 2

-powerful
-strong backwash scours the beach and removes material
- weak swash
- high wave in proportion to length
-a tail breaker as it breaks downwards with great force
-

Question 3

Constructive Waves

Answer 3

strong wash and weak backwash builds up the beach

Question 4

Coastal transportation = Longshore Drift

Answer 4

• waves approach at an angle due to the prevaling wind
• material moved up the beach by swash (same angle)
• gravity makes backwash go straight down the beach at a right angle
• this continues and the material moves from one side of the beach to the other
• can be prevented by building GROYNES
• if the coastline ????

Question 5

How are waves created ? 3 steps

Answer 5

1. WIND blows over the suface of the sea.
2. FRICTION is created which creates a SWELL in the water.
3. ENERGY of the wind causes water particles to ROTATE inside the swell and this moves the wave forward

Question 6

Size and Energy of the wave

Answer 6

How LONG the wind has been blowing 
and 
the STRENGTH  of the wind 
and
how FAR the wave has travelled (the FETCH)

Question 7

Spits - defintion

Answer 7

Where sediment is moved along the coast by a process called Longshore Drift

Question 8

Formation of Spits

Answer 8

1.Sediment move by LSD
2.When coastline changes direction LSD continues
3.wave loses energy and deposits the sand
4 Sediment builds up and out from the shore = SPIT
5. SPIT grows and may form a hook
6. Behind the SPIT : LOW energy and deposition which can lead to salt marshes

Question 9

Coastal Management Options

Answer 9

1. Hard Engineering = built structures = expensive and unsightly
2. Soft Engineering = natural and allows and encourages natural processes to occur
3. Hold the line eg Barton on Sea = stop any more erosion and protect current coastline using a mixture of H and S engineering.
4. Advance the line = reclaim land and protect
5. Managed retreat eg Porlock Bay, Sommerset = work with nature and allow gradual erosion
6. Do nothing= allow erosion to happen

Question 10

Coastal Management Methods - 6 items

Answer 10

1. Groynes
2. Revetment
3. Gabions
4. Rip Rap
5. Sea wall
6. Beach nourishment/replenishment

Question 11

“Old Harry”

Answer 11

HEADLAND EROSION = (hydraulic action and abrasion)
Forms - Cave, Arch, Stack, Stump
OLD HARRY IS ON THE ISLAND OF PURBECK
- IT IS A STACK THAT STANDS ALONE IN THE SEA

Question 12

COASTAL MANAGEMENT

SOFT ENGINEERING - 2 MAIN TYPES

Answer 12

BEACH NOURISHMENT
Replaces beach or cliff materials removed by erosion or LSD.
adv =
1. having a beaches is a natural defense to erosion and will attract tourists.
2. relatively inexpensive to do

disadv =
1.requires constant maintenance to keep replacing the lost beach material as it gets washed away.

MANAGED RETREAT eg PORLOCK BAY
ie ALLOWED TO ERODE AND FLOOD NATURALLY USUALLY WHERE AREA IS OF LOW VALUE

adv =
1. development of beaces (natural defense) and salt marshes (enviromental adv) and low cost

disadv =
1.Not free though, as people will need to be compensated for loss of their buildings and farmland due to the erosion issues.

Question 13

COASTAL MANAGEMENT

HARD ENGINEERING - 3 MAIN TYPES

Answer 13

SEA WALL (ADV AND DISADV) ???

GROYNES (ADV AND DISADV) ???

ROCK ARMOUR (ADV AND DISADV) ???