10.4 Coastal management and protection strategies

Coastal management and protection strategies are crucial in addressing the challenges faced by shorelines worldwide. From natural erosion to sea-level rise, these threats require a mix of hard and soft engineering solutions, as well as adaptive management approaches.

Integrated Coastal Zone Management offers a holistic approach to balancing environmental protection with economic development. By combining various strategies and engaging stakeholders, coastal communities can better prepare for future challenges while preserving their unique ecosystems and resources.

Coastal Environment Threats

Natural Erosion and Flooding Processes

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Top images from around the web for Natural Erosion and Flooding Processes

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  Storm surge © David Baird cc-by-sa/2.0 :: Geograph Britain and Ireland View original

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  Coastal erosion © Ian Paterson :: Geograph Britain and Ireland View original

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  Frontiers | Nature-Based Engineering: A Review on Reducing Coastal Flood Risk With Mangroves View original

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  Storm surge © David Baird cc-by-sa/2.0 :: Geograph Britain and Ireland View original

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• Coastal erosion wears away and removes sediment from shorelines through wave action, currents, and other natural forces
  • Leads to loss of land, infrastructure damage, and habitat destruction
  • Exacerbated by factors like sea-level rise and increased storm intensity
• Coastal flooding inundates low-lying areas with seawater
  • Often worsened by storm surges, high tides, and extreme weather events
  • Can cause property damage, saltwater contamination, and loss of life
• Storm surges pose significant threats to coastal areas
  • Cause temporary sea-level rise and increased wave energy
  • Intensified by climate change, leading to more frequent and severe coastal flooding

Sea-Level Rise and Climate Change Impacts

• Sea-level rise increases water volumes in oceans globally
  • Caused by thermal expansion of oceans and melting of land-based ice
  • Rates vary regionally but average about 3.3 mm per year globally
• Saltwater intrusion degrades freshwater resources and alters ecosystems
  • Affects coastal aquifers, reducing available freshwater for human use
  • Changes salinity in estuaries, impacting flora and fauna (mangroves, fish species)
• Combined effects of multiple coastal threats accelerate shoreline retreat
  • Increased erosion rates, more frequent flooding, and habitat loss
  • Greater vulnerability of coastal communities to natural disasters

Human-Induced Coastal Threats

• Coastal development alters natural shoreline processes
  • Construction of buildings and infrastructure in vulnerable areas
  • Removal of natural barriers (sand dunes, mangroves) increases risk
• Alteration of sediment transport patterns disrupts coastal equilibrium
  • Dams on rivers reduce sediment supply to coasts
  • Dredging and channel modifications change longshore drift patterns
• Pollution and habitat destruction impact coastal ecosystems
  • Nutrient runoff leads to eutrophication and algal blooms
  • Plastic pollution harms marine life and degrades coastal environments

Coastal Protection Measures

Hard Engineering Solutions

• Seawalls protect coastal areas from wave action and erosion
  • Vertical or near-vertical structures built parallel to shoreline
  • Provide immediate protection but may cause scour at base
• Groynes trap longshore sediment transport to maintain beach width
  • Built perpendicular to shoreline, often in series
  • Can cause downdrift erosion if not properly designed
• Revetments absorb wave energy and prevent erosion on banks or cliffs
  • Sloping structures often made of rock, concrete, or gabions
  • More natural appearance than vertical seawalls
• Offshore breakwaters reduce wave energy reaching the coast
  • Built parallel to shore in deeper water
  • Can create tombolos or salients, altering sediment transport patterns

Soft Engineering Approaches

• Beach nourishment restores eroded beaches by adding sand or sediment
  • Widens beaches, providing natural protection and recreational areas
  • Requires periodic replenishment, especially after storms
• Living shorelines incorporate natural elements to stabilize coastlines
  • Use vegetation, oyster reefs, and other biogenic features
  • Enhance ecosystem services while providing coastal protection
• Dune restoration and management strengthen natural coastal defenses
  • Planting of native vegetation to stabilize dunes
  • Installation of walkways and fencing to reduce human impact

Managed Retreat and Adaptation Strategies

• Managed retreat relocates coastal communities away from high-risk areas
  • Planned relocation of buildings and infrastructure inland
  • Can be controversial but effective long-term strategy
• Flood-proofing and elevation of structures reduce vulnerability
  • Raising buildings above flood levels
  • Installing flood barriers and waterproof materials
• Early warning systems and evacuation plans enhance community resilience
  • Implementation of storm surge and tsunami warning networks
  • Development of clear evacuation routes and procedures

Coastal Management Strategies

Effectiveness of Hard Engineering Solutions

• Immediate protection provided by structures like seawalls and groynes
  • Can effectively reduce erosion and flooding in target areas
  • Often favored for protecting high-value coastal assets
• Potential negative consequences of hard structures
  • Downdrift erosion caused by interruption of sediment transport
  • Habitat loss and alteration of coastal ecosystems
  • Aesthetic impacts on natural coastal landscapes
• Long-term maintenance and adaptation challenges
  • Structures may become inadequate with sea-level rise
  • High costs associated with repair and upgrading

Benefits and Limitations of Soft Engineering Approaches

• Environmental friendliness of beach nourishment and living shorelines
  • Maintain natural beach profiles and habitats
  • Enhance recreational value and tourism potential
• Frequent maintenance and replenishment requirements
  • Nourished beaches erode faster than natural ones
  • Living shorelines may need time to establish and stabilize
• Variability in effectiveness based on local conditions
  • Success depends on wave climate and sediment characteristics
  • May not be suitable for high-energy coastal environments

Adaptive Management and Integrated Approaches

• Flexibility in response to changing environmental conditions
  • Regular monitoring and assessment of strategy effectiveness
  • Adjustment of management plans based on new scientific understanding
• Combination of hard and soft engineering techniques
  • Hybrid approaches tailored to specific coastal environments
  • Example: Using groyne fields with beach nourishment
• Importance of public acceptance and stakeholder involvement
  • Community engagement in decision-making processes
  • Education and outreach to build support for management strategies

Integrated Coastal Zone Management

Holistic Approach to Coastal Planning

• ICZM considers interconnections between land, sea, and human activities
  • Addresses complex interactions in coastal systems
  • Aims to balance environmental protection, economic development, and social well-being
• Cross-sectoral cooperation and coordination
  • Involves various government agencies, NGOs, and local communities
  • Promotes integrated decision-making across different sectors (fisheries, tourism, urban planning)
• Long-term perspective in coastal management
  • Develops strategies that consider future climate change scenarios
  • Incorporates adaptive management principles to address uncertainties

Sustainable Resource Management and Ecosystem Services

• Promotion of sustainable use of coastal resources
  • Implements fishing quotas and marine protected areas
  • Encourages eco-tourism and sustainable aquaculture practices
• Maintenance of ecosystem services and biodiversity
  • Protects key habitats (mangroves, seagrass beds, coral reefs)
  • Recognizes economic value of natural coastal defenses
• Addressing complex challenges in coastal areas
  • Climate change adaptation strategies (coastal buffer zones, nature-based solutions)
  • Sustainable tourism development (carrying capacity assessments, eco-certification programs)

Stakeholder Engagement and Adaptive Management

• Importance of diverse perspectives in decision-making
  • Involves local communities, indigenous groups, and various industries
  • Uses participatory mapping and community-based monitoring programs
• Implementation of monitoring and evaluation systems
  • Regular assessment of environmental indicators and management outcomes
  • Use of remote sensing and GIS technologies for coastal change detection
• Adaptive management to respond to changing conditions
  • Periodic review and update of coastal management plans
  • Flexibility to incorporate new scientific knowledge and technologies