Coastal Management (CIE IGCSE Geography)

• There are conflicting views about using a particular type of engineering for coastal defence
• Most coastal managers aim to use a range of methods depending on the value of what is being protected
• This method is known as Integrated Coastal Zone Management (ICZM)
• ICMZ aims to use a combination of methods to best reflect all stakeholder's needs

Soft engineering methods

• Soft engineering works with natural processes rather than against them
• Usually cheaper and do not damage the appearance of the coast
• Considered to be a more sustainable approach to coastal protection
• However, they are not as effective as hard engineering methods

Soft Engineered Defences

Strategy	Description	Advantages	Disadvantages
Beach replenishment	Pumping or dumping sand and shingle back onto a beach to replace eroded material	Beaches absorb wave energy  Widens beach front	Has be repeated regularly which is expensive Can impact sediment transportation down the coast
Fencing, hedging, and replacing vegetation	Helps to stabilise sand dunes or beaches  Reduces wind erosion	Cheap method to protect against flooding and erosion	Hard to protect larger areas of coastline cliffs
Cliff re-grading	The angle of a cliff is reduced to reduce mass movement	Prevents sudden loss of large sections of cliff Regrading can also slow down wave cut notching at base of cliffs as wave energy is slowed	Does not stop cliff erosion
Managed retreat	Existing coastal defences are abandoned allowing the sea to flood inland until it reaches higher land or a new line of defences	No expensive construction costs Creates new habitats such as salt marshes	Disruptive to people where land and homes are lost Cost of relocation can be expensive Compensation to people and businesses may not be paid

Hard engineering methods

• Hard engineering involves building some form of sea defence, usually from concrete, wood or rock
• Structures are expensive to build and need to be maintained
• Defences work against the power of the waves 
• Each type of defence has its strengths and weaknesses
• Protecting one area can impact regions further along the coast, which results in faster erosion and flooding
• Hard engineering is used when settlements and expensive installations (power stations etc) are at risk - the economic benefit is greater than the costs to build

Hard Engineered Defences

Strategy	Description	Advantages	Disadvantages
Sea Wall	A wall, usually concrete, and curved outwards to deflect the power of the waves	Most effective at preventing both erosion and flooding (if the wall is high enough)	Very expensive to build and maintain It can be damaged if the material is not maintained in front of the wall Restricts access to the beach Unsightly to look at
Groynes	Wood, rock or steel piling built at right angles to the shore, which traps beach material being moved by longshore drift	Slows down beach erosion Creates wider beaches	Stops material moving down the coast where the material may have been building up and protecting the base of a cliff elsewhere Starves other beaches of sand. Wood groynes need maintenance to prevent wood rot Makes walking along the shoreline difficult
Rip-rap	Large boulders are piled up to protect a stretch of coast	Cheaper method of construction Works to absorb wave energy from the base of cliffs and sea walls	Boulders can be eroded or dislodged during heavy storms
Gabions	Wire cages filled with stone, concrete, sand etc	Cheapest form of coastal defence Cages absorb wave energy Can be stacked at the base of a sea wall or cliffs	Wire cages can break, and they need to be securely tied down Not as efficient as other coastal defences
Revetments	Sloping wooden or concrete fence with an open plank structure	Work to break the force of the waves Traps beach material behind them Set at the base of cliffs or in front of the sea wall Cheaper than sea walls but not as effective	Not effective in stormy conditions Can make beach inaccessible for people Regular maintenance is necessary Visually unattractive
Off-shore barriers	Large concrete blocks, rocks and boulders are sunk offshore to alter wave direction and dissipate wave energy	Effective at breaking wave energy before reaching the shore Beach material is built up Low maintenance Maintains natural beach appearance	Expensive to build Can be removed in heavy storms Can be unattractive Prevents surfing and sailing

Prediction

• Early warning systems allow communities to prepare (evacuate or take shelter) before flooding occurs
• Two methods are used to help forecast coastal flooding:
  • Past records (diaries, newspapers, government/council records etc)
    • These will identify areas that are at high risk of flooding and their frequency
  • Modern technology - GIS, satellite and computer monitoring, weather stations (local and national) etc
    • These allow for forecasting and tracking potential hazard events i.e.
      • Tropical storms - track the storm's path and associated storm surge
      • Earthquakes - size and position if underwater and possible tsunami outcome
• Both these methods of forecasting help officials to say when and where the event will occur
• It indicates the possible strength and scale of the flooding, and the likelihood of damage and death

Prevention

• Prevention is about taking action that reduces or removes the risk of coastal flooding
• Actions include:
  • Flood defences
    • These are built along high-risk stretches of coast 
  • Emergency centres
    • Centrally placed on higher ground where people can be safe from flooding
  • Early warning systems
    • Allows for preparation or evacuation of an area
  • Education
    • Informing local people on what to do if and when a flood occurs
  • Planning
    • Planning any new development away from high-risk-areas
    • Designing buildings to cope with low levels of flooding
      • Elevating buildings so that flood waters can pass underneath
      • Flood proof buildings with raised foundations (fixed or mechanical)
      • Reinforced barriers
      • Dry flood proofing - sealing a property so that floodwater cannot enter
      • Wet flood proofing - allows some flooding of the building
  • Buffer zones
    • Areas of land are allowed to flood before reaching settlements
      • This allows the energy in the surge to dissipate slowing down the distance the floodwater will travel
      • It can mean moving people away from the coast which could be controversial 

Coastal strategies

• Management of coastal regions is performed by identifying coastal cells
• This breaks a long coastline into manageable sections and helps identify two related risks:
  • The risk of erosion and land retreat 
  • The risk of flooding
• Identification allows resources to be allocated effectively to reduce the impacts of these risks
• The 'cost to benefit' is easier to calculate using coastal cells

Shoreline management plans

• Shoreline Management Plans (SMP) set out an approach to managing a coastline from flooding and erosional risk
• The plans aim to reduce the risk to people, settlements, agricultural land and natural environments (salt marshes etc.)
• There are four approaches available for coastal management, with differing costs and consequences:
• Hold the line
  • Long term approach and the most costly
  • Build and maintain coastal defences so the current position of the shoreline remains the same
  • Hard engineering is the most dominant method used with soft engineering used to support
• Advance the line
  • Build new defences to extend the existing shoreline
  • Involves land reclamation
  • Hard and soft engineering is used
• Managed realignment
  • Coastline is allowed to move naturally
  • Processes are monitored and directed when and where necessary
  • Most natural approach to coastal defence
  • Mostly soft engineering with some hard engineering to support
• Do nothing
  • Cheapest method, but most controversial of the options
  • The coast is allowed to erode and retreat landward
  • No investment is made in protecting the coastline or defending against flooding, regardless of any previous intervention
• Decisions about which approach to apply are complex and depend on:
  • Economic value of the resources that would be protected, e.g. land, homes etc
  • Engineering solutions - it might not be possible to 'hold the line' for moving landforms such as spits, or unstable cliffs 
  • Cultural and ecological value of land - historic sites and areas of unusual diversity
  • Community pressure - local campaigns to protect the region
  • Social value of communities - long-standing, historic communities

Background

• Typhoon Haiyan (locally called Yolanda) was one of the strongest ever-recorded tropical storm to hit the Philippines 
• It made landfall on the 8th of November 2013 as a Category 5, with sustained winds of over 195 mph (315 km/hr)
• The Philippines are a series of islands located in the South China Sea, east of Vietnam and north of Indonesia
• The islands regularly suffer from typhoons that sweep in from the southwest every year during the tropical storm season
• The islands sit in an area of usually warm ocean water, however, at time of storm, the sea temperature was 30°C
• Sea level rise (since 1900, has increased 20cm around the world) is a factor as higher seas are known to contribute to greater storm surges
• Abstracting too much groundwater has caused parts of the country to sink
• Tacloban stands at the end of a bay that is funnel shaped and this squeezes water into destructive storm surges

Formation of tropical storms

• All tropical storms need warm, deep water (>27°C and >70 m depth) and sufficient spin from the earth’s rotation (Coriolis force), hence why they form between 5-20° N and S of the equator
• Warm water encourages evaporation from the sea surface, and as the air rises, it cools, condenses, releases latent heat and forms large thunderclouds
• Heat from below causes further vertical growth and this creates an intense low pressure
• Tropical storms begin with a merging of several storms on the eastern side of an ocean
• A major low-pressure cell develops and as winds are drawn in, the whole system begins to spin anticlockwise and westwards
• Winds rotate around a central eye, where cold air descends creating an area of calm
• The strongest winds are within the wall of the eye.

Typhoon Haiyan's timeline

Path of Typhoon Haiyan November 2013

Date - Nov 2013	Development
2nd	An area of low pressure develops several hundred kilometres east of Micronesia
3rd	Haiyan begins to track westward, deepening into a tropical depression
5th	Classified as a typhoon and a low-level Public Storm Warning is issued by Philippines Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)
6th	Declared a Category 5 super typhoon by the Joint Typhoon Warning Center. PAGASA raises storm warning to highest level, indicating expected wind speeds in excess of 115 mph
7th	Haiyan's winds continue to intensify up to 195 mph. Haiyan makes first landfall at Guiuan, Eastern Samar without losing any intensity
8th	Haiyan makes five more landfalls within the Philippines before passing into the South China Seas
10th	Haiyan turns to the NW and makes landfall in Northern Vietnam, as a Category 1 typhoon
11th	Haiyan finally weakens into a tropical depression

Typhoon Haiyan's characteristics

Lowest pressure	895 mb
Peak strength	Category 5
Strength at landfall	Category 5 with 195 mph winds
Highest sustained wind speed	196 mph
Radius of typhoon strength winds	53 miles
Rainfall	400 mm
Storm surge height	15 m

Preparation for Typhoon Haiyan

• The Philippines, despite being an LEDC, take disaster preparations seriously as they have experience of typhoon impacts, as they are usually the first Pacific landmass in a typhoon's track
• The Philippines have been practicing risk reduction and resilience for decades and have published risk maps and provided evacuation shelters
• When Haiyan made first landfall, the International Charter on Space and Major Disasters was activated, this allowed relief agencies, in times of disasters, to have access to satellite data from space agencies to help in relief and recovery
• The military deployed planes and helicopters in advance to areas expected to be worst hit
• Community buildings, such as convention centres, were designated as storm shelters, but there were concerns that they would not withstand the wind
• As a result of years of community preparedness and education, there were evacuations of whole islands, such as Tulang Diyot, with all 1000 residents leaving ahead of Haiyan
• The local mayor won an award in 2011 for community work based on the “Purok system”, which is where community members agree to deposit their own money into a community fund, on a regular basis, for post-disaster assistance, rather than waiting for government aid

Impacts of Haiyan

Total economic loss	$13 billion
Homes damaged or destroyed	1.1 million
Displaced people	4 million
Number of deaths	6201
Number of people missing	1785
Number of injured people	28,626
Number of people affected	16 million

Impacts	Short-term	Long-term
Social	6201 people died  1.1 million homes lost more than 4 million displaced Casualties 28,626 from lack of aid 16 million people affected UN admitted its response was too slow, amid reports of hunger/thirst among survivors	UN feared possibility of the spread of disease, lack of food, water, shelter and medication Areas less affected; influx of refugees into the area Two months later, 21,000 families were still in 380 evacuation centres, waiting to be rehoused by the government in bunkhouses that needed to be built
Economic	Estimated at $13 billion Major sugar/rice producing areas were destroyed Between 50,000 and 120,000 tons of sugar was lost Over 130,000 tonnes of rice were lost Government estimated that 175,000 acres of farmland was damaged (worth $85 million)	The Philippines declared 'a state of national calamity’ Asked for international help the next day President Aquino was under growing pressure to speed up the distribution of food/water/medicine Tacloban city was decimated Debt is a major obstacle for the Philippines, the country is locked in a debt cycle, with more than 20% of government revenue spent on foreign debt repayments
Environmental	Loss of forests/trees, and widespread flooding Oil and sewage leaks; into local ecosystems Lack of sanitation in days following lead to a higher level of pollution Coconut plantations were said to be 'completely flattened' (coconut equated to nearly half of the Philippines agricultural exports / is the world's biggest producer of coconut oil Fishing communities were severely affected	An estimated 90 per cent of the rural population in typhoon-affected areas are small-scale farmers With 33 million coconut trees felled, international help has been sought to mill the 15 million tons of timber, lying rotting on the ground, attracting pests that threatened healthy trees Without a crop, families would not have cash to enable local markets to function

Immediate relief

• The immediate response was from the survivors, who searched flattened buildings for bodies
• The government was criticised for being slow in its response, and people began looting to find food supplies
• Roads were undamaged, but debris slowed rescue vehicles
• Airports and harbours were closed meaning emergency teams had to travel slowly on foot, which hampered aid distribution
• International charities sent emergency supplies, centred on Tacloban airport with the UK and USA sending diggers, land rovers and heavy lifting gear
• The European Commission released $4m in emergency funds and the UK Rapid Response Facility provided $8m in aid
• Twelve IFRC (International Federation of the Red Cross) Emergency Response Units worldwide were deployed
• The Philippines was also dealing with two prior natural disasters - 7.3 magnitude earthquake a month earlier (October 2013) and Typhoon Bopha in 2012. Together these disasters meant that the Philippines were low on resources - financial, material and human