Coastal management

Question 1

What is beach nourishment?

Answer 1

soft engineering strategy

• sediment is taken from offshore sources to build up the existing beach
• widens beach which works as a buffer for oncoming waves so less erosion
• can replace sediment lost eg. through storm surges

Question 2

What are the advantages and disadvantages of beach nourishment?

Answer 2

advantages
- leads to lower rates of erosion - protects cliffs behind
- increases tourist potential
- cost effective and natural looking

disadvantages
- needs constant maintenance
- dredging (removal of sediment from elsewhere) has consequences on habitats and can lead to erosion elsewhere

Question 3

What is managed retreat?

Answer 3

soft engineering strategy

• controlled flooding of low-lying coastal areas
• usually in areas at high risk of erosion

Question 4

What are the advantages and disadvantages of managed retreat?

Answer 4

advantages
- cheap compared to paying for sea defences
- creates a saltmarsh which provides habitats and a diverse ecosystem
- saltmarsh can act as a natural defence against flooding and erosion

disadvantages
- land lost as it is reclaimed by the sea
- landowners need to be compensated which is expensive

Question 5

What are the advantages and disadvantages of doing nothing?

Answer 5

• leaves the coastline as it is without putting in place any coastal management strategies, leaving the area to be flooded and eroded (usually because it is not of economic value)
• no money spent on defences
• landowners need to be compensated

Question 6

What is dune regeneration/mangrove planting?

Answer 6

soft engineering strategy

• planting specific plants such as mangroves or marram grass which has a large frictional area, causing sand to be deposited
• marram grass has long roots which stabilises dunes
• dissipate wave energy to prevent flooding and erosion

Question 7

What are the advantages and disadvantages of dune regeneration?

Answer 7

advantages
- maintains natural environment
- provides wildlife habitats
- relatively cheap and sustainable
- stabilises fragile dunes

disadvantages
- time consuming
- easily damaged by people
- people must be kept off certain areas, may reduce tourism

Question 8

What is rock armour?

Answer 8

hard engineering strategy

• large boulders placed at the foot of cliffs
• dissipate wave energy by absorbing impact of waves and permeable which allows water and sediment to pass through
• protect cliffs from undercutting
• approx £3000/metre

Question 9

What are the advantages and disadvantages of rock armour?

Answer 9

advantages
- cheap to install and maintain
- natural looking
- prevents erosion of cliffs

disadvantages
- dangerous access to beach
- increased costs when rock is transported or imported great distances

Question 10

What is a sea wall?

Answer 10

hard engineering strategy

• concrete/rock barriers built along the front of cliffs
• they are often recurved at the top so wave energy is reflected back on itself
• modern sea walls designed to dissipate not reflect wave energy
• approx £4000/metre

Question 11

What are the advantages and disadvantages of sea walls?

Answer 11

advantages
- good defence where energy is high
- long life span
- storm drains so water can flow back out to sea

disadvantages
- expensive to build/maintain
- can effect beach access
- recurved top can increase beach erosion by scouring the base

Question 12

What are groynes?

Answer 12

hard engineering strategy

• timber or rock ‘fences’ built out to sea at right angles to the coast
• trap sediment being moved along the shoreline by LSD which widens beach
• wide beach acts as a buffer to oncoming waves to absorb energy
• approx £5000/metre

Question 13

What are the advantages and disadvantages of groynes?

Answer 13

advantages
- cheap
- retain wide and sandy beaches so wave energy is absorbed - prevents erosion
- do not effect beach access

disadvantages
- visually unappealing
- deprives areas down the coastline of sediment which shifts the problem rather than solving it

Question 14

What are revetments?

Answer 14

Hard engineering strategy

• timber/rock fences with open slats placed parallel to the coastline
• absorb wave energy allowing water and sediment to pass through, trapping sediment to build up the beach
• approx £2000/m

Question 15

What are the advantages and disadvantages of revetments?

Answer 15

advantages
- less beach material eroded
- wave scour prevented
- cheaper and less intrusive than other strategies

disadvantages
- short life span
- unsuitable when wave energy is high
- access problems

Question 16

What are gabions?

Answer 16

Hard engineering strategy

• rocks and boulders encased in wired mesh
• absorb energy from waves and allow water and sediment to pass through
• approx £100/m

Question 17

What are the advantages and disadvantages of gabions?

Answer 17

advantages
- cheap and efficient
- uses local materials

disadvantages
- short life span
- wires can break and cause injury
- visually unappealing

Question 18

What is an estuary barrage?

Answer 18

Hard engineering strategy

• acts as a dam across an estuary to prevent flooding and creating freshwater lakes behind them
• can be controlled to open or close depending on sea conditions
• £30 billion each
• eg. Thames barrier

Question 19

What are the advantages and disadvantages of estuary barrages?

Answer 19

advantages
- protect large areas
- very effective
- long life spans

disadvantages
- very expensive to build and maintain
- huge environmental impacts on mudflat areas
- negative impacts on tourism industry

Question 20

What are SMP’s?

Answer 20

Shoreline management plans

• uses a combination of approaches that aim to be cost-effective and long lasting including soft and hard engineering strategies
• the overall plan aims to be sustainable economically, socially and environmentally
• 20 SMP’s in the UK

Question 21

What 3 strategies do SMP’s use?

Answer 21

hold the line - strengthen/maintain existing defences

no active intervention - natural processes operate without human intervention

managed realignment - deliberate flooding of previously protected areas. Saltmarshes and mudflats can then trap sediment and create natural and diverse defences and ecosystems

Question 22

What is an ICZM?

Answer 22

Integrated coastal zone management plan

• contributes to the sustainable development of coastal zones by the application of an approach that respects the limits of natural resources and ecosystems ‘ecosystem based approach’
• designed to integrate views and interests of all stakeholders and coordinate policies affecting coastal zones eg. fishing/industry

Question 23

What are the sustainable features of SMP’s and ICZMs

Answer 23

• holistic view
• conserve biodiversity
• work with the environment using nature-based solutions
• long term
• good for locals
• resource efficient - locally sourced
• planned well to protect against sea level rise