Event Abstract
Responding to coastal disasters and enhancing resilience to coastal erosion and flooding needs a holistic, participatory and inter-disciplinary approach where science is embedded in the social, cultural and economic context in which coastal communities live.
THESEUS developed such a systematic approach to delivering both a low-risk coast for human use and healthy habitats for evolving coastal zones subject to multiple change factors. THESEUS adopted two main cross-cutting solutions which are a) the use of case studies, and b) the development of unified tools, i.e. a book of guidelines and a Decision Support System.
Innovation and best practices in coastal engineering
The conventional coastal protection measures can be divided in hard structures and beach nourishment. The latter- often called a soft measure- is an intervention in which sand or gravel is placed on the beach or in the near-shore zone. Hard structures are sea dikes, revetments, breakwaters and artificial reefs as well as groins. The THESEUS project studied the resistance of the crest and rear side of grass covered sea dikes, as well as methods for upgrading conventional rubble mound coastal protection structures, the use of artificial reefs as a wave dampening structure, and best practice for beach nourishment and application of groins. The use of floating structures as coastal protection tools has not yet been widely used. THESEUS considered their use as coastal protection tools by studying the reduction in wave heights landward of these devices.
Preserving and enhancing coastal ecosystems
Habitats which offer the greatest potential for coastal defence are mobile and consist mainly of unconsolidated particles. Sediment management in dune systems, marshes, seagrass meadows and open coasts is therefore critical and requires a holistic approach.
Alongside appropriate management of natural habitats, it is clear that hard engineering interventions will also be required in some locations. The work in THESEUS shows how adopting a systems perspective allows the process understanding of habitats to be integrated with coastal engineering and social aspects of flooding to augment and increase the options available to flood risk managers, and be compliant with the habitats directive.
The governance dimension
The way to approach the governance dimension of flood and erosion risk has been renovated by focusing on key assessment and mitigation approaches. The project analysed risk perception in terms of paradigmatic tensions associated with conflicting pertinence, normative and evidence claims. As such, THESEUS has allowed for the clear identification of norms as the main source of varying perceptions regarding coastal risks. On the mitigation front THESEUS developed a simplified model of insurance taking explicitly into account spill-over effects. This has allowed for a rethinking of the issues of scales and linkages, allowing developments that go beyond the private/public dichotomy.
Decision making for a sustainable coast
Within the large scope of THESEUS, one of the main objectives was to design a tool to help decision makers in defining optimal strategies to minimize risk in the short, medium and long term scenarios. The resulting software reproduces in a simplified way the most relevant physical processes (coastal erosion and flooding) induced by waves and sea-levels taking into account physical and non-physical drivers, such as climate change, subsidence, population growth and economic development.
