© oxford university press 2009 quit part 2 managing river and coastal environments: a continuing...
Post on 13-Jan-2016
212 Views
Preview:
TRANSCRIPT
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
2.52.5 How can humanHow can human activity influence andactivity influence and alter river and coastalalter river and coastal environments?environments?
Part BPart B
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
A bay in San Francisco, California, USA
How do people make use of the coastal areas?
Can you suggest how people make
use of the coastal areas?
Can you suggest how people make
use of the coastal areas?
Can the activities
you mentioned be found in
Hong Kong?
Can the activities
you mentioned be found in
Hong Kong?
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
How do people make use of the coastal areas?
In general, the following activities are found:
Tourism and recreation
Urban developmentPower generation
Industrial activities
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
How do people alter the coast?A Reclamation
The development of commercial and residential buildings in West Kowloon(Credit: Liang Wing Hang Yanchap)
Reclamation is carried out to obtain land for urban development.
It changes the shape and form of the coastline.
Reclamation has been carried out near old Star Ferry in Central for the construction of expressways
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
How do people alter the coast?B Dredging
A dredger(Credit: Liang Wing Hang Yanchap)
When deposition is active at a harbour, dredging is carried out to ensure that the port can accommodate large ships.
Dredging is also practised for obtaining materials for reclamation and construction.
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
Coastal erosion and deposition are continuing processes. They can shape the shoreline and this has
profound impact on human activities.
People need to manage the coast to ensure the continuance of
human activities. Two approaches are often used.
A Hard approach (structural response)
1. Groynes2. Breakwaters3. Sea walls4. Rock armour
B Soft approach (non-structural response)
1. Beach nourishment
2. Mangrove planting
3. Coral reef growing
4. Vegetation planting
5. Relocation and land use zoning
How do people manage the coast?
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
1 Reclamation
What are the consequences of coastal alterations?
In Hong Kong, reclamation projects on both sides of Victoria Harbour narrow the harbour.
It increases the speed of water currents and affects the safety of navigation.
It may also bury the habitats of aquatic organisms and disturb aquatic ecosystems.
The land at both sides of Victoria Harbour
Reclaimed land
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
2 Dredging
What are the consequences of coastal alterations?
Dredging shingle would expose the coast to erosion, e.g. the case of Hallsands village in the UK.
Dredging may stir up sediment and pollutants from the seabed, which can disturb aquatic ecosystems.
1. Shingle beach before dredging of sand and shingle offshore
Sea
Sea level
2. Cliff eroded by sea after removal of shingle
3. Part of the village was destroyed
4. Present location of cliff
Hallsands village (abandoned)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
3 Pollution and the ecological balance
What are the consequences of coastal alterations?
Sewage and waste from homes, businesses, factories, hotels and other recreational facilities could upset marine ecosystems.
Structural work may block sediment movement. It leads to changes in the natural habitat. Tourist facilities along a beach in
Cancun, Mexico
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
What are the limitations of coastal management strategies?Groynes
Longshore drif
t
Groynes block longshore drift
Beaches further along the coast may be more vulnerable to wave erosion
Groynes in Dorset, UK (Credit: Rex Features)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
What are the limitations of coastal management strategies?Breakwaters
Accumulation of sand behind the breakwater
Breakwater
Breakwaters protect the coast behind (Credit: Rex Features)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
What are the limitations of coastal management strategies?Sea walls and rock armours
Expensive to build and maintain
A sea wall Rock armour
Expensive if rocks are imported
Rocks must be large and heavy enough to
remain stable
Dangerous to young children
(Credit: Tsui Chung Pong David)(Credit: Corbis)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
What are the limitations of coastal management strategies?Beach nourishment
The beach of Repulse Bay
Sediment of the beach may lose
after a storm
Regular maintenance is
needed
Costly
(Credit: Getty Images)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
What are the limitations of coastal management strategies?Mangrove planting and coral reef growing
Mangrove planting
Careful protection is needed for
young mangroves
Coral reef growing
Ensuring that the water is free from
pollution
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
What are the limitations of coastal management strategies?Vegetation planting, relocation and land use zoning
Vegetation planting
Planting vegetation on cliffs or poor soil is difficult
Relocation and land use zoning
People with investments and properties at the
coast are reluctant to move
Costly compensation
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
Rivers and coasts are our valuable resources.
We should manage them in a sustainable way.
To set up a sustainable management strategy, we need to
- examine the balance between four parties;
- carry out cost-benefit analysis.
SocietyEnvironment
Economy Government
What should people do to face the continued challenges posed by the management of river and coastal environments?
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
5. Investigate the balance between four aspects in
the management strategy
1. Define objectives
2. Consider the impact of human
3. Set indicators for use with
environmental-based management
4. Design effective assessment methods
6. Implement management strategy
7. Evaluate outcome
Let’s look at how the UK works out her shoreline
management plans (SMPs)!
Management strategy evaluation model
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
5. Investigate the balance between four aspects in
the management strategy
1. Define objectives
2. Consider the impact of human
3. Set indicators for use with
environmental-based management
4. Design effective assessment methods
6. Implement management strategy
7. Evaluate outcome
Case study: Shoreline management plans (SMPs) in the UK
1. Define objectives
The aims of SMPs:1. Improve understanding of coastal
processes;2. Set up long-term planning of coastal
defences and land use.
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
5. Investigate the balance between four aspects in
the management strategy
1. Define objectives
2. Consider the impact of human
3. Set indicators for use with
environmental-based management
4. Design effective assessment methods
6. Implement management strategy
7. Evaluate outcome
Case study: Shoreline management plans (SMPs) in the UK
- Assessing the risk to people and the natural environment;
- Devising a sustainable management strategy with four policy options:• Do nothing• Hold the line• Advance the line• Retreat
3. Set indicators for use with
environmental-based management
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
1. Define objectives
2. Consider the impact of human
3. Set indicators for use with
environmental-based management
4. Design effective assessment methods
5. Investigate the balance between four aspects in
the management strategy
6. Implement management strategy
7. Evaluate outcome
Case study: Shoreline management plans (SMPs) in the UK
5. Investigate the balance between four aspects in
the management strategy
Case: SMP for Holderness coast- Rolston:1. Tackle wave erosion2. Major land use: agriculture3. Low population- Bridlington:1. Tackle wave erosion2. Major land use: holiday resorts,
nationally important place for seabirds
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
5. Investigate the balance between four aspects in
the management strategy
1. Define objectives
2. Consider the impact of human
3. Set indicators for use with
environmental-based management
4. Design effective assessment methods
6. Implement management strategy
7. Evaluate outcome
Case study: Shoreline management plans (SMPs) in the UK
Case: SMP for Holdernesscoast- Rolston:Option: Do nothing- Bridlington:Option: Hold the line(Methods: Promenade, sea
walls, groynes)
6. Implement management strategy
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
A The ‘hard’ approach: Structural response1 Groynes
Groynes are barriers built at right angle to the coastline to stabilize beach deposits.
Longshore
drif
t
Groynes
Longshore drift moves the sand deposits parallel to the shore.
Groynes in Dorset, UK
(Credit: Rex Features)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
A The ‘hard’ approach: Structural response2 Breakwaters
Breakwaters are long piers built offshore to reflect and dissipate the energy of incoming waves.
The coastline is protected from erosion.
breakwaterstyphoon shelter
The Aberdeen Typhoon Shelter(Credit: Lam Man Lok)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
A The ‘hard’ approach: Structural response3 Sea walls
Sea walls are built parallel to the shoreline to protect the coast by reflecting wave energy.The coastline is protected from wave erosion.
Curved concrete sea wall
Cliff
Wave energy is reflected by the
presence of the sea wall
Seabed Toe protection Sheet piling
(Credit: Corbis)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
A The ‘hard’ approach: Structural response4 Rock armour
Rock armour is a barrier of large, irregular shaped rocks or concrete placed at the coastline.
They protect the coastline from wave erosion.
(Credit: Getty Images)Rock armour
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
High Island Reservoir, East Dam
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
B The ‘soft’ approach: Non-structural response1 Beach nourishment
Stabilizing the coastline by adding a large quantity of sand or shingle to the beach.
Repulse Bay in Hong Kong is an example of beach nourishment.
Repulse Bay is a famous tourist spot in Hong Kong(Credit: Getty Images)
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
B The ‘soft’ approach: Non-structural response2 Mangrove planting
Mangroves can protect the coast against erosion by strong waves and winds by binding the soil.
Mangroves can bind the soil and thereby prevent coastal erosion
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
B The ‘soft’ approach: Non-structural response3 Coral reef growing
Coral can reduce the speed of waves approaching the coast and thereby protect beaches against coastal erosion.
Coral reefs under the sea
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
B The ‘soft’ approach: Non-structural response4 Vegetation planting
Planting vegetation on cliffs can increase their stability and thereby stabilize the shore.
Structures on a sea cliff
© Oxford University Press 2009 Quit
Part 2 Managing river and coastal environments: A continuing challenge
B The ‘soft’ approach: Non-structural response5 Relocation and land use zoning
Removing or relocating coastal properties to safe ground helps prevent loss of life and property.
In the eroding coastal areas, only limited, or even no development, is allowed.
top related