ICE design and practice guides : Coastal defence

The desire to preserve assets in the coastal zone has resulted in the widespread installation of coastal defences. The whole task of planning, designing, building and managing coastal defences in a cost-effective, environmentally acceptable and sustainable manner is a complicated undertaking, involving a wide range of skills, Based on contributions from numerous experienced specialists, Coastal Defence offers an introductory handbook to this challenging subject matter. The Guide starts with a review of the history of coastal defences in the UK, and of the legal administrative arrangements for their construction. This is followed by a description of the important processes causing changes to the coast, and examples of the commonest types of coastal defences. It then explains the information that is needed to decide whether installing defences is justifiable, and how to choose appropriate types of defence for further consideration. These decisions have to take account of the technical, environmental and economic aspects of any proposed scheme. In the remainder of the report, the issues of detailed design, construction and post-construction activities are explained.

Coastal Defence will be an essential resource for civil engineers working with coastal defences, management and engineering. Local Authorities and civil engineering students will also find this guide informative and a valuable reference tool.

Contents

COASTAL DEFENCES

• History and background
• Coastal defences – who builds them
• Coastal zone management
• A strategic approach to coastal defence
• COASTLINE PROCESSES
• Waves
• Tides
• Coastline changes
• Changes on open coasts
• Estuarial coastline changes
• REVIEW OF COASTAL DEFENCE TECHNIQUES
• Introudction
• Linear defences
• Introudction
• Embankments
• Revetments
• Seawalls
• Beach Management
• Beach recharge
• Beach recycling and bypassing
• Beach control structures
• Groynes
• Breakwaters
• Sills
• Dune stabilisation methods
• Estuarial coastal defences
• Surge and tidal barriers
• Satmarsh management
• Cliff Stabilisation
• STEPS REQUIRED IN CHOOSING COSTAL DEFENCE OPTIONS
• Introduction
• Data gathering
• Introduction
• Collection of data on physical processes and characteristics
• Data on benefits and costs
• Data on environmental constraints and opportunities
• Studying the ‘non-intervention' option
• Assessing hydrodynamics and sediment transport rates
• Assessing existing defences
• Predicting future changes in the coastline and standards of defence
• Preliminary economic evaluation
• Preliminary environmental appraisal
• Preliminary public consultation
• Assessing coastal defence options
• CHOOSING A PREFERRED OPTION
• Technical appraisal
• Introduction
• Functional effectiveness
• Durability and residual life
• Sustainability
• Constructability
• Economic Appraisal
• Introduction
• Present values/discounting
• Costs
• Benefits
• Economic comparision of options
• Enviornmental appraisal
• Background and need for environmental appraisal
• Scoping
• Environmental surveys
• Impact identification and evaluation
• Mitigation, compensation and enhancement
• Risk
• DESIGN DEVELOPMENT
• Introduction
• Mathematical modelling
• Physical modelling
• Scheme promotion and approval

PRACTICALITIES OF COASTAL DEFENCE CONSTRUCTION

• Access and delivery/storage of materials
• Tidal restrictions
• Seasonal and phased construction
• Seasonal working
• Phased construction
• Planning and environmental considerations
• Construction plant and methods
• Measurement and detailing
• Construction risks
• Construction supervision
• POST PROJECT MONITORING, MAINTENANCE AND APPRAISAL
• Introduction
• Construction appraisal
• Monitoring the condition of defences
• Maintenance
• Evaluation of defence performance
• Environmental monitoring
• Post-project appraisal
• Data storage, sharing and future use
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