Coastal Landscapes - Coastal Management Policy Decisions

Important Coastal Management Questions:

1. Do we have to hold the line? e.g Hard Engineering
2. What is a suitable defence?; what are the options?
3. How much will the loss be compared to the cost? CBA (cost-benefit analyse)
4. Who is involved/affected?
5. What will the knock-off effects be?
6. Environment?

Policy Decisions:

• Advance The Line: A strategy to move the defence of an area seaward of its existing position e.g Netherlands
• No Active Intervention: Carry out no coastal defences activity except for safety measures
• Hold The Line: Strategy to continue to hold the line of defence where it is e.g Blackpool and Mappleton
• Retreat The Line: Encourage the movement of the shoreline landward of its present position in a managed or controlled manner e.g Formby Sand Dunes

Sustainable Coastal Management:

• Old approach was hard engineering but it was too expensive and maybe not needed e.g Spurn Head was built without care and the main focus was protection and maybe not the environment
• New approach: Considers economic, social and environmental factors, still uses hard engineering where it must e.g Blackpool but uses more soft engineering e.g Formby. Don't always hold the line, and SMP with sustainability the key.

Coastal Management For The Future:

• Shoreline Management Plan (SMP): For coastal defence issues to match sediment cells.
• Integrated Coastal Zones Management (ICZM): Broader issues including transport and business from the EU
• Coastal Re-Alignment: Allowing the sea to reclaim land e.g flooding fields so that they become salt marshes.
• By using new strategies they are trying to: Ensure sustainability e.g easier to maintain and compatible with other coastal areas, cheaper and more effective overall, reduce stakeholders conflict, environmental needs e.g protecting the ecosystem, replace hard engineering with soft engineering where it is beneficial.

Shoreline Management Plan (SMP):

• Made public in 1995 to address the conflicts between competing for coastal interests
• Sustainable, compatible and takes account of natural coastal processes as well as the needs of people
• Thus came sediment cells – 11 of them. Interrupting the movement of one cell will have no significant effect on the other.

Integrated Coastal Zone Management (ICZM):

• Objective to establish sustainable levels of economic and social activity whilst protecting the coastal environment
• Brings the stakeholders to facilitates the integration of their interests and responsibilities.
• Overcomes the piecemeal approach
• Recognises the contact on river catchments and the importance of sediment cells

Medmerry RSPB Reserve: Sussex:

• Environment agency was the key player
• In the past, they would regrade the beach and now a flood wall has been created
• Objectives: Manage the flood risk, create habitats, involvement of community
• Cheaper, sustainable and it also acts as a flooding barrier.

Coastal Landscapes - Coastal Management

• 45% of England’s coast is buttressed with sea walls, groynes or artificial beaches

Hard Engineering:

• Involves some type of building (using hard materials like wood and rock)
• Blackpool spent £62 million on a sea wall and it is £3000 per metre to repair
• Examples include: Groyne, Wood or steel piling, concrete walls, wooden revetment, recurves steel wall, Gabion, rip-rap.

Positives & Negatives of Hard Engineering:
Positives:	Negatives:
Protection against erosion so recession stops	Costs are expensive
Controls and reduces flooding so houses and towns are protected	Impacts the environment
Improves urban landscape	Interferes with sediment (starvation)
Socially sustainable	Unsightly
	Needs repairing which is expensive

Soft Engineering:

• Uses soft, natural resources such as sand, sand dunes or changing cliffs and land
• Examples include: Beach nourishment, cliff regrading and drainage, dune stabilisation.

Positives & Negatives of Soft Engineering:
Positives:	Negatives:
Often cheaper	Not effective enough
More natural looking (amenity value)	Requires natural material on land which might not be there
Better for the environment	Could still erode
Fewer ‘knock on’ effects down the coast	Needs constant management
Allows investment in other areas where hard engineering is needed	Socially less accepted

Who Manages The UK Coastlines:

1. Government: Provide overall funding for coastal defence works
2. Environment Agency: Scientists who decide what defences are needed
3. Private Companies: Engineering firms paid to complete the work
4. Local Stakeholders: They are involved in the decisions and requirement of defences.
5. National Trust: Environmentalist who put pressure on bodies to care for ecosystems 
   Hard Engineering Types:

   Blackpool’s Sea Wall
   Advantages	Disadvantages
   Reduces erosion	Very expensive
   Interacts with people	Eyesore
   Allows for easy access to beach	Needs constant maintenance
   	Disrupts people who being built

   
   
   

   Hornsea’s Rip-Rap
   Advantages	Disadvantages
   Allows new habitats to form	Blocks access to the beach
   Reduces erosion	Allows some erosion behind the defence
   Not an eyesore and works with the coastal zone

   
   
   

   Mappleton’s Rock Groyne
   Advantages	Disadvantages
   Protection of erosion	Sediment starvation may occur
   Deposition may occur instead	Allows some erosion behind the defence
   	Recession retreat will occur much quicker

   
   
   

   Offshore Breakwater - Norfolk
   Advantages	Disadvantages
   Allows the beach to be left as it is	Eyesore
   Buffers waves	Sediment starvation can occur
   Reduces energy of the waves	Expensive to maintain

   
   
   

   Revetments
   Advantages	Disadvantages
   Acts as a flood defence	Expensive
   Buffers wave	Some erosion can occur
   Reduces energy of wave	Deposition can occur behind it

   Soft Engineering Types:

   Beach Nourishment
   Advantages	Disadvantages
   Improves beach for tourists	Expensive to maintain
   Buffers waves	Damages wildlife and ecosystems
   Reduces sub-aerial processes from occurring	Reduces erosion, does not stop it.

   
   
   

   Sand Dunes - Formby
   Advantages	Disadvantages
   Improves beach for tourists/doesn’t ruin one	Expensive to maintain - fences
   Creates new habitats	Cannot protect the coast when there is a big storm
   	Reduces erosion, does not stop it.

   
   
   

   Cliff Regrading & Drainage
   Advantages	Disadvantages
   Cheap to implement	Expensive to maintain
   Buffers waves	Damages wildlife and ecosystems
   Reduces sub-aerial processes from occurring	Reduces erosion, does not stop it.

   
   
   Summary:

• Hard and Soft engineering options are available to manage coasts
• In the UK, the key players include the government, the Environment Agency, local residents, farmers and businesses.
• Hard engineering is the most effective to stop erosion and flooding for high value land, but it is also the most expensive, damaging for environment and disruptive to sediment movement.
• Soft engineering is generally cheaper, more environmentally friendly, and less impacting, but it is less viable for urban coasts and therefore socially and practically not always possible (erosion and flooding risk!)
• In reality, both hard and soft are needed for a holistic approach

Coastal Landscapes - Impacts of Coastal Recession & Flooding

• Affects settlements and those who live on the coast
• Ranges from damages include: Loss of property and death
• Losses can be classified as economic, social or environmental

Impacts of Coastal Recession & Flooding At Holderness Coast:

• Social costs from rapid recession include: people’s lives and families being disrupted.
• Education and social networks are interrupted.
• Tourism is reduced
• Social and economic costs e.g houses collapsing may lead to mental health being affected as well as physical health
• Losses of homes in Mappleton
• Damage to infrastructure

Bangladesh And Coastal Erosion:

• Delta at the Ganges River have been eroding
• Tropical storms cause coastal flooding
• Economic and social loss for farmers
• Loss of jobs creating an environmental refugee.
• Impacts are more severe because the country is poorer
• Water borne diseases.

Coastal Flooding Impacts:

• More severe than recession as it can impact a big area
• Costs more and causes more deaths
• Social and economic impacts
• Worst impacts occur in densely populated areas

1953 Storm Surge In The UK & The Netherlands:

• 2.5m high storm surge in the North Sea
• 1800 dead in the Netherlands and 300 dead in the UK. Most dead along the Home Counties in England – 250 dead, and South Zeeland in the Netherlands.
• 30k houses evacuated in the UK
• 30k affected in the Netherlands
• 1600km of coastline was affected in the UK
• £50 million damage in the UK
• Bought the Delta Works which is now the best sea defences in the world.
• Low pressure, high tides and strong windows all contributed.

2013 Typhoon Haiyan:

• Most powerful storm, dubbed as “Super Typhoon Haiyan”
• Surge was 5m high
• Tacloban destroyed by 120mph winds and coastal flooding
• 6000 dead
• Economic cost included: Houses lost, clean and rebuild, loss of workers and damaged infrastructure. E.g San Juanico Bridge completely destroyed.

Impacts From Eustastic Sea Level Rise In Male, Maldives:

• Buildings flooded
• Land lost under the ocean
• Loss of income from tourists
• Social impacts have been affected because of loss of homeland

Summary:

• Flooding and erosion of coasts causes economic, social (& environmental) losses
• Low-lying areas like estuaries, deltas and small islands most vulnerable
• Holderness recession impacts include loss of property, damaged roads, job losses, relocation, reduced amenity value
• 1953 storm surge from North Sea killed over 2000 people in UK and Netherlands, Typhoon Haiyan, Philippines 6000 killed
• Storm surges are raised sea-levels due to low pressure storms, strong winds and when high tides they flood the land
• Bangladesh is also prone to coastal flooding and erosion, with impacts such as farmland loss, disease and refugees
• Small islands like The Maldives are at high risk due to the low-lying land and ‘environmental refugees’ are having to relocate to other countries

Coastal Landscapes - Coastal Flooding

• Coastal flooding occurs when normally dry, low-lying land that is flooded by seawater.
• Caused by an area becoming submerged in water causing river banks to burst or to begin to coastal flood.
• Sometimes, rivers and coastal flooding can combine e.g around estuaries or on a delta. If there are a storm high tides and heavy rain, coastal areas and river waters can flood the land e.g Hull and the Holderness Coast.

Physical Reasons	Human Reasons
Storms	Lack of defences and they can be old and worn
Large Waves	Humans living near the coast
Storm Surges (from low pressure)	Humans increasing the likelihood of flooding e.g deforestation.
High tides
Low-lying land
Tsunamis

Global/International Reasons	Local Reasons
Coastalisation and population growth	Poor coastal defences
Sea level rise	Tsunami vulnerability
More strong waves/destructive waves	Sub-aerial processes
More storm surges	Coastal defences changing the dynamic equilibrium.

Case Study – Bangladesh:

• Low-lying estuarine land as the Ganges River Delta
• Large storm surges due to tropical storms
• River flooding from monsoon rain increases water build up in estuaries areas.
• Deforested Mangroves trees mean less natural protection from waves leading to a build-up of erosion and less coastal protection.
• Subsidence due to sediments being deposited on land which rises land level
• Sea level rise due to global warming

Storm Surges:

• A temporary rise in sea level due to low-pressure storm systems (depressions).
• Cause: Low pressure causes sea level to rise and strong winds to blow bulges of water against the coast
• Worse when they occur with a high tide of flooding is more likely
• Can rise up to 2m high in Eastern England
• 5m high during Typhoon Haiyan
• Its’ severity is often increased due to strong onshore waves and winds.

Climate Change Increasing Coastal Flooding:

• A eustatic sea level rise
• Increases coastal flooding globally because climate change is increasing the energy in the atmosphere

Why Does More Flooding Occur:

• Magnitude and the frequency of storms is higher = more storm surges
• More powerful waves and winds occurring more often
• Sea level rise around 20cm over the last 100 years leading to more natural coastal flooding
• Storm surges and destructive waves are more common

Where Is Affected The Most By Coastal Flooding:

• Bangladesh – low-lying deltas and storms
• Philippine – typhoons with a big magnitude and frequency
• Maldives – small low lying islands
• Netherlands – land is already below sea level

Mini Case Study – Maldives:

• Eustatic sea level rise
• Low lying, high-density population, limited sea defences, no high ground, directly below sea level.

Mini Case Study – Netherlands:

• ¼ is already below sea level
• Has the worlds best sea defences, hard engineering of sea walls and gates for high tides.

Summary:

• More people live on coasts due to migration and population growth therefore flooding risk is higher than ever.
• Storm surges are the biggest reason for coastal flooding of high magnitude
• Local coastal flooding due to deforestation and subsidence
• Global warming is increasing the risk of flooding due to eustatic sea level rise
• Bangladesh has been hit by storm surges = floods
• Most at risk are low lying areas and islands close to the sea
• Lots of uncertainty over sea level rise.

Coastal Landscapes - Sea Level Change

• Long-term sea-level change occurs on a timescale

Climate Change Affecting Sea Level:

• Ice age build up and the climate begins to change.
• Less water in the sea and the sea-level falls.
• New land can also form by the release can still happen. T
• his means that sea level falls because waster goes over land which is built on snow so it builds up and stays there.

What Causes Sea-Level Change:

1. Ice age/glacial periods (long term)
2. Global warming (short term)
3. Other physical processes e.g tectonics and subsidence

Two Types Of Sea Level Change:

1. Eustatic: Volume of water changes e.g more water floating leads to a raised height
2. Isostatic: Height of the coastal land changes so the land rises out or sinks into coastal water.

Eustatic:

1. Ocean water warms on coasts so it changes volume. If the water is warmer it will expand slightly so the sea level will very slightly rise.
2. Amount in the ocean increases from ice on land e.g glaciers therefore more water flows in the ocean raising the sea level
3. Thermal Expansion: Water is heated and it expands, oceans are 4-8 thousand deep so a slight expansion adds some millimetres which can be significant.
4. Ice Melt: Land ice melts and flows into the sea = more water in sea. Opposite can also occur.

Isostatic Change:

1. Weight of the ice is compressed, and rock is pushed into the mantle,
2. sea levels fall because of thermal contraction and water is stored as ice.
3. Thermal expansion occurs = raised sea level.
4. The land rebounds slowly as the weight of ice has increased which causes local sea levels to fall.

Sea Level Change Landforms:

Submergent:

• Landforms that form due to being under water (submergent) e.g Fjords, Rias and the Dalmatian Coast.

Fjords:

• Mainly in Norway
• Very large, deep, steep-sided valley that have flooded

How Do They Form:

1. Huge amount of snow and ice build-up in northern latitudes
2. V-shaped valleys on the coast because rivers erode the land
3. Glaciers flow out of ice sheets eroding the valley to make them U-shaped
4. Ice melts and sea levels rises eustatically which is, submerged to form a fjord.

Rias:

• River valley that is v-shaped and flooded when sea levels rise, not been eroded
• Due to the eustatic sea level rising from the last ice age, rising sea level forms rias
• Example: Southern Ireland Coast near Cork.

Dalmatian Coast, Croatia:

1. Long parallel mountains formed via tectonic forces
2. Sea levels rise because the ice ages have ended
3. Eustatic sea level rise has flooded the coast
4. Top of the mountain stick out as long parallel islands.

Emergent Landforms:

• Landforms that form due to land coming out of the water e.g Raised beaches and fossil cliffs

1. Marine erosion creates cliffs and a wave cut notch
2. Ice age ends and all the weight of the ice sheets and glacial are removed from land
3. Isostatic rebound occurs: Land rising back out of the mantle
4. Raises the beaches and cliffs up so they are away from the coast
5. Eustatic sea level fall can also produce the same features

Global Sea Level Rise Due To Climate Change:

• If the sea level rises due to climate change, it will raise 60m and will flood the following areas: Amsterdam, London, Berlin, Venice and Baghdad

Bangladesh:

• One of the most at risk countries from climate change and global sea level rise
• Large river delta from the Ganges
• Delta: Very flat and low-lying areas of sediment deposited by rivers into coastal waters

Tectonic Sea Level Change:

• Earthquakes and tectonics can also change sea levels isostatically. An earthquake in 2016 in New Zealand uplifted a long area of coast raising the sea floor out permanently.

Summary:

• Sea level rise and fall by many metres on a long-term timescale e.g mainly due to the ice ages
• Eustatic change is the volume of water changing from land ice melting and thermal expansion.
• Isostatic change means land levels rises or falls
• Submergent landforms include: fjords, rias and Dalmatian Coastline
• Emergent landforms include: raised beaches and fossil cliffs
• Global sea level rise is occurring at a rapid rate due to climate change and causing risk to low lying coastlines e.g Netherlands, Bangladesh and the Holderness Coastline in Yorkshire.

Coastal Landscapes - Recession at the Holderness Coast

Holderness Coast As An Example:

• Rapid retreat impacts people property and the access to roads.
• Rotational slumps (mass movement) forming a steep-terraced cliff profile and land forms which threaten paths etc.
• Has receded up 4km in 2000 years
• Europe’s fasted eroding coastline
• Many towns have been lost and coastal recession is affecting many towns

Physical Factors:	Human Factors:
Marine Erosion: Wave type, power, angle of wave attack, and frequency of storms, how high tides are.	Old poor quality sea defences or none at all.
Geology: Lithology, rock type, structure, unconsolidated material, sub-aerial processes like weathering and mass movement	Other sea defences up the coast that trap sediment and therefore reduce sediment down the coast which will lead to more erosion
Morphology: Narrow beach, headlands, offshore bars, exposure to the North Sea

Why Does Holderness Coast Erode:

• Boulder clay (unconsolidated material)
• Areas with no sea defences
• Storms and waves which are powerful in winter
• Little sheet from the open north sea
• Sub-aerial processes like rotational slumping is common.

Boulder Clay in Detail:

• Cliffs expand to the powers of long fetch and storm waves
• Sub-Aerial processes retreat the coast as machine weathering from rainfall leading to rotational slumping
• At high tide storm waves hit the cliff and sediment hitting the cliff
• Wave cut notches forms when waves attack undercuts the cliff causing it to collapse
• Weak geology as unconsolidated material breaks easily with some hydric action

How Can Humans Interfere With Recession Rates?

• Mapleton, a rock amour groin was built to trap sediment from long-shore drift and to also widen the beach. This means more sands is collected and buffers the wave energy before it hits the cliff therefore reducing erosion.
• This starves the coast father down and the beach gets smaller therefore recession rate increases known as sediment starvation
• Today Mapleton has increased erosion further down the coast and no materials is supplied from longshore drift.

Coastal Recession Change:

• Wind direction, fetch, tides, seasons, weather systems and storms all change temporally i.e. through time such as long arm or short term as well as spatially.

Bangladesh Delta:

• Soft sediment from the Ganges River is ‘dredged’ to keep waterways open for boats.
• This increases erosion as sediments are removed
• Manure trees on the coast are cut down – these naturally protect the coast from erosion.