Coastal Defences aims to present the broad spectrum of methods that engineers use to protect the coastline and investigates the sorts of issues that can arise as a result. The first section of the book examines 'traditional' hard techniques, such as sea walls and groynes, whilst the second looks at the more recent trend of using techniques more sympathetic to nature. By looking at each of the main methods of coastal protection in detail, the book investigates the rationale for using each method and the consequent management issues, presenting a case for and against each of the techniques.
The emphasis now placed on the concept of sediment cells as boundaries for coastal defence groups, and the development of SMPs, should help CPAs realise the importance of natural processes at the coast when designing defence and protection schemes. However, this will only be the case where defence groups exist, and where CPAs take up the challenge of developing SMPs. Coastal landscapes have been produced by the natural forces of wind, waves and tides, and many are nationally or internationally important for their habitats and natural features. Past practices at the coast, such as the construction of harbours, jetties and traditional defence systems may have contributed to the deterioration of the coast. English Nature (1992) have argued that if practices and methods of coastal defence are allowed to continue, then coastlines would be faced with worsening consequences, including: The loss of mudflats and the birds which live on them Damage to geological Sites of Special Scientific Interest (SSSIs) and scenic heritage by erosion, due to the stabilisation of the coast elsewhere Cutting of sediment supplies to beaches resulting in the loss of coastal wildlife Cessation through isolation from coastal processes, of the natural operation of spits, with serious deterioration of rare plants, animals and geomorphological and scenic qualities (English Nature, 1992) A number of designations, provided by national and international legislation do exist to aid conservation.
Around 469,000 households and business in England are at risk of flooding and this figure is likely to rise of the next century because of factors such as climate change. The Environment Agency is responsible for managing the risk from main rivers and the sea in England and Wales. This report looks at their maintenance of 24,000 miles of flood defences and the construction of new defences. It notes the progress made since the last report in 2001 (HC 299 2000-01) and sets out the areas where there is room for further improvement.
The objective of coastal management is the preservation of coastal resources whilst simultaneously satisfying the sometimes conflicting interests and requirements of protection, development, usage and conservation. Given the ever increasing awareness of coastal planning and management on an integrated basis this volume compounds the general change in perspective.
Effective coastal engineering is expensive, but it is not as costly as neglect or ineffective intervention. Good practice needs to be based on sound principles, but theoretical work and modelling also need to be well grounded in practice, which is continuously evolving. Conceptual and detailed design has been advanced by new industry publications since the publication of the second edition. This third edition provides a number of updates: the sections on wave overtopping have been updated to reflect changes brought in with the recently issued EurOtop II manual; a detailed worked example is given of the calculation of extreme wave conditions for design; additional examples have been included on the reliability of structures and probabilistic design; the method for tidal analysis and calculation of amplitudes and phases of harmonic constituents from water level time series has been introduced in a new appendix together with a worked example of harmonic analysis; and a real-life example is included of a design adapting to climate change. This book is especially useful as an information source for undergraduates and engineering MSc students specializing in coastal engineering and management. Readers require a good grounding in basic fluid mechanics or engineering hydraulics, and some familiarity with elementary statistical concepts.
Managed realignment has been a preferred coastal management strategy in England in the 21st century and has also been increasingly implemented elsewhere. Climate change and environmental and financial concerns have led to a shift from the traditional ‘hold-the-line’ approach of coastal protection towards more flexible soft engineering options. Managed realignment is a relatively new soft engineering alternative aiming to provide sustainable flood risk management with added environmental and socio-economic benefits by creating space for coastal habitats to develop more dynamically. The natural adaptive capacity of coastal habitats and the ecosystem services they provide underpin the sustainability of managed realignment. However, many definitions of managed realignment exist and the understanding of what the term actually represents in practice has evolved through time and varies regionally. This book clarifies the definitions and terminology used in the literature and proposes that managed realignment is used as a general term that encompasses the many different methods of implementation worldwide, including: removal, breach and realignment of defences; controlled tidal restoration (which includes regulated tidal exchange and controlled reduced tide); and managed retreat. These methods of implementation are explained and illustrated with examples from around the world. In addition to a general overview of emerging policies and current practices, specific chapters discuss approaches adopted in different locations, including the Netherlands, the UK and Maui (USA). The UK experience is presented from the perspectives of three sectors: the National Trust (a charity organisation that owns 10% of the coastline of England and Wales), the Environment Agency (the organisation responsible for implementing government policy concerning flood and erosion risk) and a private consultant involved in the planning, design and delivery of managed realignment projects. Taking a wider perspective to consider the range of implementation methods, the viability of managed realignment as a long-term coastal management strategy is discussed. Recent national and regional strategies worldwide give managed realignment an increasing role in climate change and flood risk management. Gaining stakeholders and public support is fundamental for the success of emerging coastal management strategies. However, public perception and stakeholders engagement are often cited as a factor limiting the wider uptake of managed realignment. Results from a recent survey are used to benchmark the current thinking about the potential, the performance and the limitations of managed realignment in the UK and elsewhere. Current opinions about managed realignment are often not clearly defined, partly due to many projects being relatively recent. There is a general perception of great potential to provide sustainable flood risk management with added environmental benefits. However, the views of stakeholders are considerably more negative and notably contrast with the views of practitioners and researchers. The only clear and dominant agreement across all groups of respondents is that better understanding about the long-term evolution of sites is needed.
These conference proceedings include 41 papers from the Seventh International Conference on Coastlines, Structures and Breakwaters organised by the Institution of Civil Engineers.
