hard engineering and soft engineering structures

Question 1

sea wall

Answer 1

how it works: reflects waves back out to sea - prevents erosion - acts as a barrier - reduce flooding
cost: expensive to build and maintain
disadvantage: creates strong backwash - erodes under the wall

Question 2

revetment

Answer 2

how it works: slanted structures - foot at cliffs (absorb wave energy, prevent cliff erosion)
cost: expensive to build - relatively cheap to maintain
disadvantage: create a strong backwash - erode under

Question 3

gabions

Answer 3

how it works: rock filled cages - foot of cliffs (absorb wave energy - reduce erosion)
cost: cheap
disadvantage: ugly

Question 4

riprap

Answer 4

how it works: boulders piled up - absorb wave energy - reduce erosion
cost: fairly cheap
disadvantage: can shift in storms

Question 5

groynes

Answer 5

how it works: fences built at right angles - trap beach material - creates wider beaches - slow waves (energy) greater protection from flooding and erosion
cost: quite cheap
disadvantage: starve down-drift beaches - thinner beaches don’t protect the coast as well - increasing erosion and flooding

Question 6

breakwaters

Answer 6

how it works: concrete blocks or boulders - force waves to break offshore - erosive power is reduced
cost: expensive
disadvantage: can be damaged in storms

Question 7

earth bank

Answer 7

how it works: mounds of earth acts as a barrier to prevent flooding
cost: quite expensive
disadvantage: can be eroded

Question 8

tidal barrier

Answer 8

how it works: built across river estuaries, retractable floodgates - raised to prevent flooding from storm surges
cost: very expensive
disadvantage: very very expensive (building causes environmental issues)

Question 9

tidal barrage

Answer 9

how it works: dams built across river estuaries - generate electricity - water trapped behind dam at high tide - controlled release of water - prevent flooding from storm surges
cost: very expensive
disadvantage: disrupt sediment flow - cause increased erosion elsewhere in the estuary

Question 10

beach nourishment

Answer 10

sand and shingle added to beaches from elsewhere - creates wide beaches (reduces erosion)

Question 11

beach stabilisation

Answer 11

reducing the slope angle and planting vegetation stabilise sand - creates wide beaches , reduce erosion of cliffs

Question 12

dune regeneration

Answer 12

created or restored - nourishment or stabilisation of the sand - provide a barrier absorbing wave energy - preventing flooding and erosion

Question 13

land use management

Answer 13

vegetation needed to stabilise - easily trampled and destroyed - vulnerable to erosion - wooden walkways and fenced off areas - reduce vegetation loss

Question 14

creating marshland

Answer 14

encouraged by planting appropriate vegetation - stabilising sediment - reduce the speed of waves - reduces erosive power - less flooding

Question 15

coastal realignment

Answer 15

managed retreat - allowing the sea to flood inland - vegetation over time will create marshland

Question 16

management strategies - how are they going to be sustainable in the future?

Answer 16

hard engineering - usually expensive and disrupts natural processes
soft engineering - cheaper, less time and money to maintain - good to environments
soft engineering - more sustainable management strategy - lower environmental impact and economic cost.

Question 17

shoreline management plans

Answer 17

sediment cells - a plan is devised for how to manage areas - all local authorities in one sediment cell co-operate

Question 18

Integrated coastal zone management

Answer 18

1. considers all elements of the coastal system - aims to protect in a natural state - allowing people to use it
2. integrated -
   . viewed as a whole - land and water is interdependent
   . different uses are considered
   . local, regional and national levels of authority all have an input into the plan
3. dynamic strategy - decisions re-evaluated if the environment or demands on the area change

Question 19

Case study:
Sundarbans Region - Bangladesh & India

Answer 19

. region in the southwest Bangladesh and East India (Bay of Bengal)
. protected as a National Park - largest mangrove forest in the world
. flat and low-lying - intersected by channels (small islands)
. rare species of plants and animals
. coastal system - dynamic equilibrium - material deposited by rivers (growth of mangrove forests) - eroded by the sea (size of sediment stores)

Question 20

what opportunities does the Sundarbans regions bring?
Economic:

Answer 20

home to 4 million people - economic benefits to the region:
. flat, fertile ideal for growing crops
. rich ecosystem - fish, crabs, honey and nipa palm leaves (baskets)
. provide timber for construction

Question 21

what opportunities does the Sundarbans regions bring?
services:

Answer 21

mangroves - natural defence against flooding - barrier against rough seas - absorb excess water (easier to live and grow crops)
protect coast - against coastal erosion - roots bind soil together

Question 22

what opportunities does the Sundarbans regions bring?
development and wealth:

Answer 22

tourism - attracted to mangroves and wildlife
cargo ships - transporting goods - some channels dredged to make passage easier
power plant - providing energy for people
(all causing environmental issues)

Question 23

how does location bring risks to occupation and development of the Sundarbans?

Answer 23

. lack of fresh water for drinking and irrigation - fresh water is diverted further upstream
. growing population - demand for services - mangrove forests being removed - risk of flooding
. flooding - salinisation (hard to grow crops)
. dangerous animals - attack humans
. lack of employment and income
. low-lying - rising sea levels (global warming)
. poor region - communication is low - don’t receive flood warnings (1/5 of housing have mains electricity)
. access is difficult - few roads - limits opportunities - hard to receive necessities

Question 24

what are the attempts to over come risks that occur in the Sundarban region?
Resilience:

Answer 24

being able to cope :
. increasing access to clean water and sanitation - improve health and quality of life
. better infrastructure - improving access - can lead to deforestation
. electricity - extended to more areas - easier to announce flood warnings - create jobs
. efforts to decrease poverty - increase food security - could be over farmed (environmental issues)
. NGOs offer training in sustainable methods (fishing and farming)

Question 25

what are the attempts to over come risks that occur in the Sundarban region?
mitigation:

Answer 25

reducing the severity of hazards:
. 3500 km of embankments - prevent flooding - gradually being eroded - 800 km - vulnerable to being breached (storms)
. protect existing mangrove forests - replant - difficult to prevent illegal forest clearance - unclear whether mangroves will withstand rising sea levels
. cyclone shelters - early warning systems - help people shelter and evacuate - may not have transport to help them evacuate quickly

Question 26

what are the attempts to over come risks that occur in the Sundarban region?
adaptation:

Answer 26

adjusting behaviour - reduce risks and increase benefits:
. salt-resistant varieties of rice - cope with flooding and sea level rise - reduce biodiversity increase vulnerability to pests and diseases
. increase tourism - providing jobs and income - could introduce further environmental issues
. infrastructure on stilts - can’t adapt roads like that
. sustainable adaptations - non-intensive farming practises - promoting ecotourism - ensure environment remains undamaged and usable for future generations