Coasts

Question 1

What are the 4 management options at a coastline and explain

Answer 1

1. Hold the line - maintain current position - often hard engineeeing
2. Advance the line - extend coastline - build up beach e.g nourishment
3. Manages retreat - allowing retreat within management e.g creating salt marshes
4. Do nothing

Question 2

What are the 5 types of erosion?

Answer 2

1. Hydraulic action - force of water against cliff
2. Wave quarrying - breaking waves trap air against cliff - air trapped and compressed, pressure builds
3. Attrition - rocks hitting against each other or abrasion wearing rocks down
4. Solution - chemicals dissolve rocks - not common in sea bc water alkaline
5. Cavitation - bubbles in sea may explode under pressure - can be against rock - pressure

Question 3

Name 4 landforms

Answer 3

1. Tombolo- forms similar to spit - ridge or sand/shingle which joins a mainland and an island
2. Barrier beach - a ridge of sand or shingle which joins 2 headlands - parallel to coast - firms lagoon behind
3. Bar - ridge of sand/shingle which forms across mouth of river, or bay or harbour - usually parallel to coast
4. Offshore bar- partly submerged ridges of material

Question 4

What are the two types of spits

Answer 4

1. Simple spit - a bar of sand without barbs or hooks

2. Compound spits - spits with barbs or hooks on their landward side

Question 5

Conditions for sand dune formation

Answer 5

1. Large tidal range - exposure so sand dries out
2. Large quantity of sediment available
3. Dominant onshore winds - blows dry sand up the beach

Question 6

Sand dune types

Answer 6

1. Embryo dune - no more than 1m high, plants: Lyme grass
2. Fore dune - drought resistant - up to 5m, plants: Lyme grass, marram grass
3. Yellow dune - more shelter, more plants, humus later build, up to 10m
4. Grey dune - sheltered from wind, soil forms, 100% vegetation
5. Dune slack - before mature dune, plants adapt to damp and sheltered conditions
6. Mature dunes - 100m from shoreline, support shrubs and mabs trees

Question 7

Eustatic change

Answer 7

Global change in sea level due to rise or fall in sea level itself
- either thermal expansion or land ice melt

Question 8

Isostatic change

Answer 8

Sea level change due to land rising or falling relative to the sea
- occurs over long period of time

Question 9

Landforms of submergent coastlines

Answer 9

1. Rias - river valley at the coast inundated by the sea (an unglaciated river valley)
2. Fjords - formed when glacial troughs are flooded - long and steep-sided
3. Dalmatian coasts - valleys flooded by rising sea levels - tops of valleys remain above surface of the water - looks like islands

Question 10

Landforms of emergence

Answer 10

1. Marine platforms - fall in sea level/land rising causes former shoreline to be exposed
2. Raised beaches - land rises/ sea level falls - more coastline exposed
3. Relict cliffs -

Question 11

Hard engineering strategies

Answer 11

1. Sea wall
2. Groynes
3. Gabions
4. Revetments - sloping wooden concrete structures at foot of cliff
5. Barrages - partly submerged structures containing sluice gates to control flow of the sea
6. Offshore reefs - material e.g concrete boulders sunk offshore - dissipate wave energy

Question 12

Slapton sands, what has been done/defences?

Answer 12

• sea wall put in place at Torcross - rebuilt numerous times - last completed sea wall 1980
• Storms in 2001 undermined section of the road - caused Slapton Line Partnership to form
• 2002 new 2 way road built 21 metres back from previous road
• 12,000 tons of shingle moved from strete gate to protect the line
• jan 2014 £250,000 spent on moving 25,000 tons of shingle from one end of torcross to the other

Question 13

Challenges of Slapton sands

Answer 13

• 2001 storms undermined section of the road - took 12 months for new section to open (single trade in meantime)
• Slapton Line Partnership have to balance economic and environmental issues
• the £250,000 wasted on moving shingle in torcross bc it didn’t last
• 2016 section of sea wall collapsed - A379 temporarily closed - 3500 people temporarily left without bus service - repairs took a year
• problem of protecting the ley or retreating the road

Question 14

Sustainability at Slapton Sands

Answer 14

• Shingle movement proven not to be cost effective

- sea wall has had few problems - won’t last forever

Question 15

Background odisha

Answer 15

In India

Very dynamic coastline - subject to change

Question 16

Risks at odisha

Answer 16

1. Erosion increasing at the coasts - risk to coastal communities
2. Human intervention shifts problem further along the beach
3. Majority of states population live on coastal plain - subject to natural hazards
4. Ecosystem may be damaged with sea level rise

Question 17

Opportunities in Odisha

Answer 17

1. Offshore benefits - oil, natural gas, seabed mining
2. Potential for offshore wind, tidal, wave power
3. Tourism important - beaches and wildlife major attractions
4. Jobs in coastal fishing and aquaculture

Question 18

ICZM in odisha

Answer 18

Integrated Coastal Zone Management

• developed ICZM in odisha - promote sustainable coast
• co-ordinates sustainable management for coastlines
• project is a venture income committees e.g Indian government, world bank
• individual villages been consulted about some of the issues
• issues included: biodiversity conservation, vulnerability to disaster

Question 19

Mangroves in odisha

Answer 19

• amount of mangroves severely reduced bc of room for building and agriculture
• mangroves slow waves down and provide protection for coastal communities
• offshore ecosystems provide livelihood for fisherman and locals
• super-cyclone Kalina in 1999 hit l, villages with 4 or more km of mangroves has no deaths and those with less than 3km had deaths
• Wetlands International (an NGO), Indian gov and ICZM project are trying to reverse decades of mangrove destruction - its sustainable and appropriate coastal management scheme