Coastal Erosion & Flooding Strategies (SL IB Geography)

Coastline Management

• Sediment (littoral) cells divide the coastline 
• This cell system makes it easier for coastal planning and management 
• Each cell has its own system of coastal planning and management
  • In England and Wales, there are 11 cells
• Management strategies protect our coastlines from emerging threats:
  • Flooding 
  • Coastal erosion

Shoreline Management Plans

• A Shoreline Management Plan (SMP) operates in each cell
• SMPs consider the effects of different management strategies
• They aim to produce better management strategies in each cell 
• There are 4 main types of shoreline management:
  • Hold the line – using hard or soft engineering to stop the shoreline retreating from erosion
  • Managed retreat – moving the coastline to a point further inland (realignment)
  • Advance the line – moving the coastline further into the sea 
  • No active intervention – a typical “do-nothing”, letting natural processes occur
• The type of management strategy depends on: 
  • The threat of coastal erosion and rising sea levels
  • How much economic or agricultural value the land may have
  • Cultural or social value the land may have
  • Environmental and ecological value
  • Cost of management strategies 

Coastal cells of England and Wales

Coastal cells of England and Wales

Integrated Coastal Zone Management (ICZM) 

• Within the coastal system, a change in one place may impact another 
• The ICZM takes these issues into account with coastal management planning
• The ICZM is useful for understanding the coast as an entire system of marine processes, people, the environment, and onshore and offshore activities
• The ICZM aims to balance and manage all issues and viewpoints by:
  • Assessing what is occurring at the coast
  • Identifying all those affected and managing plans accordingly
  • Ensuring sustainability
  • Balancing the natural and the human
  • Discussing future changes and what could occur
  • Allowances for changing plans
• This means a solution will benefit all stakeholders

• Hard engineering is a method of coastal management
• These are man-made structures that help to reduce the risks of coastal erosion and flooding
• They significantly change natural coastal processes
• They are typically expensive and damage the environment
• Hard engineering solves issues at one point on the coast, but exacerbates issues in another area

Types of Hard Engineering 

Management strategy	Definition	Advantages	Disadvantages
Groynes	Wooden, metal or rock barriers lining the beach, perpendicular to the ocean	Increase sediment build-up by trapping the sediment moved by longshore drift Builds up and widens beaches Reduces erosion in particular areas	Other areas experience increased erosion as groynes block sediment movement They are unnatural and unattractive and prevent leisure activities Expensive and require management
Revetments	Wooden, metal or rock slopes which absorb /deflect wave energy	Reduce erosion  Cheaper than other hard-engineering methods	May need maintenance Can be unattractive and prevent beach access
Sea walls	Huge concrete structures that absorb/deflect wave energy	Their curved surface protects the land from flooding caused by storm waves Protect tourist areas e.g. beach huts Prevent erosion	Unattractive Very expensive – including maintenance Wave energy moves elsewhere, causing erosion
Gabions	Rocks enclosed by mesh at the bottom of cliffs	Absorb wave energy Cheaper	Metal wires may be subject to corrosion or breakages Unattractive and unnatural
Riprap (rock armour)	Large boulders at the shoreline	Absorbs wave energy Doesn’t need lots of maintenance so cost-effective in the long run Looks more natural	Hazardous if rocks move Expensive to transport materials
Coastal barrages	Dam-like structures, partially submerged under the water	Keep the water level more consistent Used for hydroelectricity	Expensive Not environmentally friendly

• Soft engineering harnesses the power of nature to protect coastlines
• It is much less damaging to the environment than hard engineering
• It’s sustainable – it’s cheaper and more long-term

Types of Soft Engineering 

Management strategy	Definition	Advantages	Disadvantages
Beach nourishment/replenishment	Expanding the beach by moving sediment into an area that has been subject to erosion	Improves the visual aspect and functionality of beaches Protects cliffs from erosion and inland areas from flooding risks	Requires repeated replenishment May have negative effects on the area where sediment was removed
Cliff regrading/stabilisation	Changing the shape of cliffs, e.g. changing the steepness of a slope	Reduces erosion and landslides Adding vegetation can give it a more natural look	Expensive Can cause habitat loss
Managed retreat (coastal realignment)	Leaving the shoreline to retreat naturally. Letting natural processes take over and breach current defences	Natural flooding defences can develop, e.g. salt marshes Sustainable and cheap	People may lose housing or land Can cause social issues Relocation of housing is costly
Ecosystem support e.g. dune regeneration	Adding vegetation and managing natural processes	Stabilises soil, which reduces erosion risks Looks natural and brings ecological benefits Cheap and sustainable	Can be easily affected by adverse weather or climate change Non-native species can impact the soil

Holderness Coast

The Holderness Coast

• Located in the East Riding of Yorkshire, running from Flamborough Head to Spurn Point, the Holderness Coast is home to features of erosion and deposition, such as caves, arches, stacks, stumps and spits
• One of the fastest-eroding coastlines in Europe
• Soft clays make up the coastline, causing a coastal retreat of around two metres per year
• Much land has already vanished over the past few hundred years
• The Holderness Coast is an important place to preserve, but it is under enormous pressure and in vital need of management

Shoreline Management of the Holderness Coast

• In 1991 in Mappleton, groynes were built to save the town and surrounding roads from coastal erosion:
  • Cost-benefit analysis showed it was cheaper to buy groynes than to rebuild a new road
  • This caused reduced sediment loads further down the coast. Increased erosion washed farmlands and livelihoods away 
• This produced different perspectives on holding the line or doing nothing
• Politicians and councillors held “do-nothing” views, purely from a financial perspective because it would significantly reduce costs
• Locals favoured “holding the line”, with fears of losing their homes and farmland 
• Spurn Head is a spit on the Holderness coastline. Here, due to storm erosion, a “do-nothing” approach was decided upon
• Holderness Borough Council benefitted from reduced costs to protect Spurn Head
• “Do-nothing” forced the local community to relocate
• The Yorkshire Wildlife Trust had concerns about the importance of habitats and ecosystems and the heritage of the area
• This Shoreline Management Plan may have been effective for some but was a failure for others
  

ICZM at the Holderness Coast

• In 2000, the East Riding Yorkshire Council set up the ICZM for the East Riding Coastal Area
• This ICZM was created because of Holderness’ main issues:
  • High erosion rates
  • Declining industries
  • Threats to communities
• The ICZM aims to manage social, environmental and economic problems across the entire Holderness coastline
• It also planned to re-evaluate the effectiveness and limitations of the Shoreline Management Plan

Effects and perspectives

• The 100-page ICZM document for the East Riding coastal area sets out its ICZM strategies 
• The document outlines differing categories for its action plan
• Each category contains multiple policy action plans

An example of policy action plans in each category

Category	Policy action plan
Involving and implementing	Publishing the ICZM
Managing coastal change	Remove current defences that are unsafe
Transport	Park and ride and public transport improvement
Tourism	Encourage sustainability for local businesses through guidance strategies
Recreation	Education programmes, warning signs and water quality information
Land use planning	Design guides for coastal villages
Rural issues	Community partnership development
Environment/nature conservation	Education and campaign on marine litter
Archaeology and the historic environment	Create a project for coastal zone assessment to guide management decision-making
Fisheries	Improved policing of illegal activities e.g. dredging
Power generation	Discuss the potential for wind and wave energy
Business and industry	Training and upskilling