Project Summary: Nature-based coastal defence solutions have increasingly been recognized as more sustainable alternatives to conventional hard engineering approaches against climate change. These include using wetlands, mangroves, coral and oyster reefs as a buffer zone, which can attenuate waves and, in a regime of moderate sea level rise, the sediment trapping in such zones can keep pace with sea level. Wetlands and mangroves are regions in which more salt-tolerant species exist, which can protect freshwater species behind them. Nature-based defences have been deployed in the USA, Netherlands and UK and also in some parts of China, with varying degrees of success. In deltas undergoing fast urbanisation, applying nature-based solutions can lead to competition for space with other land uses, e.g. land-reclamation. For optimised management, the question of how much space is required by nature-based solutions must be addressed. However, our current knowledge of the size-dependent defence-value and resilience of different ecosystems is insufficient. Additionally, we lack full understanding of the methods needed for ecosystem creation for coastal defence, as previous restoration efforts have suffered low success rates. The current proposal aims to develop process-based understanding and predictive models of ecosystem size requirements and how to create ecosystems for coastal defence, using the world's largest urban area, the Pearl River Delta (PRD) in China, as a model system. Delta-scale mangrove area monitoring and hydrodynamic modelling will be conducted to study recent wetland area changes and estimate the optimisation of ecosystem spaces for defence, under contrasting scenarios of climate change and land-reclamation. This large-scaled study will also provide underpinning boundary conditions for local-scale experiments and modelling. A set of experiments using novel instruments will be conducted to improve our insights into the processes influencing mangrove resilience and propagation. Innovative measures of using dredged materials and oyster reefs to facilitate mangrove establishment will also be tested experimentally. Local-scale models will incorporate the new experimental knowledge to predict mangrove bio-geomorphic dynamics and provide guidelines for management. The developed models and knowledge will be directly applied in the design of a pilot eco-dike project due to be constructed, in collaboration with our project partners. We will consider how to address resilient urban planning and management, in terms of combining spatial planning and disaster management by optimising land use, institutions and mechanisms for more sustainable urbanisation, exploring eco-dynamic design options to provide opportunities for nature as part of the urban development processes. Summary of the UK applicants' contribution to the project: The UK applicants will lead Work Task 1: Wetland area monitoring/hydrodynamic modelling. This work task will provide an over-view of the bio-physical conditions, including the morphological and land-use aspects of the PRD and its regional setting, for the present day, and under future climate projections of sea level and storms. The UK team will implement a high resolution unstructured-grid model (FVCOM) for the Pearl River Delta (PRD) for hydrodynamics, waves and sediment transport which will provide the interface between the larger scale atmospheric and oceanic boundary conditions and the smaller-scale process studies and ecosystem modelling to be carried out by our Dutch and Chinese partners. This model, together with regional sea level projections, will be used to provide quantitative scenarios for the local area ecological modelling.

Project Summary: Nature-based coastal defence solutions have increasingly been recognized as more sustainable alternatives to conventional hard engineering approaches against climate change. These include using wetlands, mangroves, coral and oyster reefs as a buffer zone, which can attenuate waves and, in a regime of moderate sea level rise, the sediment trapping in such zones can keep pace with sea level. Wetlands and mangroves are regions in which more salt-tolerant species exist, which can protect freshwater species behind them. Nature-based defences have been deployed in the USA, Netherlands and UK and also in some parts of China, with varying degrees of success. In deltas undergoing fast urbanisation, applying nature-based solutions can lead to competition for space with other land uses, e.g. land-reclamation. For optimised management, the question of how much space is required by nature-based solutions must be addressed. However, our current knowledge of the size-dependent defence-value and resilience of different ecosystems is insufficient. Additionally, we lack full understanding of the methods needed for ecosystem creation for coastal defence, as previous restoration efforts have suffered low success rates. The current proposal aims to develop process-based understanding and predictive models of ecosystem size requirements and how to create ecosystems for coastal defence, using the world's largest urban area, the Pearl River Delta (PRD) in China, as a model system. Delta-scale mangrove area monitoring and hydrodynamic modelling will be conducted to study recent wetland area changes and estimate the optimisation of ecosystem spaces for defence, under contrasting scenarios of climate change and land-reclamation. This large-scaled study will also provide underpinning boundary conditions for local-scale experiments and modelling. A set of experiments using novel instruments will be conducted to improve our insights into the processes influencing mangrove resilience and propagation. Innovative measures of using dredged materials and oyster reefs to facilitate mangrove establishment will also be tested experimentally. Local-scale models will incorporate the new experimental knowledge to predict mangrove bio-geomorphic dynamics and provide guidelines for management. The developed models and knowledge will be directly applied in the design of a pilot eco-dike project due to be constructed, in collaboration with our project partners. We will consider how to address resilient urban planning and management, in terms of combining spatial planning and disaster management by optimising land use, institutions and mechanisms for more sustainable urbanisation, exploring eco-dynamic design options to provide opportunities for nature as part of the urban development processes. Summary of the UK applicants' contribution to the project: The UK applicants will lead Work Task 1: Wetland area monitoring/hydrodynamic modelling. This work task will provide an over-view of the bio-physical conditions, including the morphological and land-use aspects of the PRD and its regional setting, for the present day, and under future climate projections of sea level and storms. The UK team will implement a high resolution unstructured-grid model (FVCOM) for the Pearl River Delta (PRD) for hydrodynamics, waves and sediment transport which will provide the interface between the larger scale atmospheric and oceanic boundary conditions and the smaller-scale process studies and ecosystem modelling to be carried out by our Dutch and Chinese partners. This model, together with regional sea level projections, will be used to provide quantitative scenarios for the local area ecological modelling.

Infrastructure is vital for society - for economic growth and quality of life. Existing infrastructure is rapidly deteriorating, the rate of which will accelerate with increasing pressures from climate change and population growth, and the condition of the large majority of assets is unknown. Stewardship of infrastructure to ensure it continuously performs its function will be a colossal challenge for asset owners and operators. The performance of new infrastructure assets must be monitored throughout their life-cycle because they are being designed and constructed to withstand largely unknown future conditions. The UK must be better prepared to face these grand challenges by exploiting technology to increase understanding of asset deterioration and improve decision making and asset management. This research is central to EPSRC's priority area of Engineering for Sustainability and Resilience. The goal is to transform geotechnical asset management by developing new, low-cost, autonomous sensing technologies for condition appraisal and real-time communication of deterioration. This new approach will sense Acoustic Emission (AE) generated by geotechnical assets. AE is generated in soil bodies and soil-structure systems (SB&SSS) by deformation, and has been proven to propagate many tens - even hundreds - of metres along structural elements. This presents an exciting opportunity that has never been exploited before: to develop autonomous sensing systems that can be distributed across structural elements (e.g. buried pipes, pile foundations, retaining walls, tunnel linings, rail track) to listen to AE - analogous to a stethoscope being used to listen to a patient's heartbeat - and provide information on the health of infrastructure in real-time. The idea to use AE sensing to monitor geotechnical assets in this way is novel - it is expected to lead to a disruptive advance in monitoring capability and revolutionise infrastructure stewardship. AE has the potential to increase our understanding of how assets are deteriorating, which could lead to improved design approaches, and to extract more information about asset condition than existing techniques: not only deformation behaviour, but also, for example, changes in stress states, transitions from pre- to post-peak shear strength, and using correlation techniques it will be possible to locate the source of AE to target maintenance and remediation activities. AE sensing will also provide real-time warnings which will enable safety-critical decisions to be made to reduce damages and lives lost as a result of geotechnical asset failures. The number of asset monitoring locations required per unit length to achieve sufficient spatial resolution will be less than other monitoring techniques, and significantly lower cost. Piezoelectric transducers, which sense the AE, are now being developed at costs as low as a few tens of pence per sensor - this recent technological advance makes this research timely. AE sensors could be installed during construction to monitor condition throughout the life-cycle of new-build assets (e.g. HS2), and retrofitted to existing, ageing assets. This will be the most fundamental and ambitious investigation into the understanding of AE generated by SB&SSS yet attempted. The findings will mark a major leap forward in scientific understanding and our ability to exploit AE in novel asset health monitoring systems. The fellowship aims to develop robust diagnostic frameworks and analytics to interpret AE generated by geotechnical assets. This will be achieved using a powerful set of complementary element and large-scale experiments. The outcomes will be demonstrated to end-users and plans will be developed with collaborators for: full-scale field testing with in-service assets to demonstrate performance and benefits in intended applications and environments; and implementation in commercial products that could have significant societal and economic impact.

The past decade has seen significant developments in the approaches to assessing and managing flood risk. Throughout this period major research projects (such as the FREE, Floodsite, FRMRC, iCOASST, RASP) and industry driven innovations (particularly within the insurance sector, water companies and environmental consultants) have all contributed to these advances. As a result of these multiple (but largely independent) strands of innovation the UK has established a pre-eminent position in the science and practice of flood risk analysis and long term infrastructure investment planning. Programmes such as the National Flood Risk Assessment (NaFRA) and the Long Term Investment Strategy (LTIS) (undertaken by the Environment Agency) have built upon this knowledge and continue to represent leading international practice. LTIS is particularly noteworthy as the first national infrastructure investment strategy that is explicitly based on national flood risk analysis. Although the past decade has been powerful in driving innovations it has, understandably, led to a proliferation of techniques that are difficult for practitioners and researchers to access and build upon. Many users are now confused as to what is best practice, and the credibility of the results. Recent publications that question some of these results have been a legitimate challenge to complex environmental models. It is now timely to confirm, consolidate and disseminate the current state-of-art through concerted knowledge transfer (KT) and provide the platform for future advances and collaboration between business and academia. The concerted knowledge transfer proposed here will provide a significant contribution to: (i) enable stakeholders (both leading consultancies and infrastructure providers) to capitalize on existing risk analysis capabilities to target investments to build resilience; (ii) reinvigorate a wave of co-innovation within system risk analysis and investment planning; (iii) maintain UK's pre-eminence in the fields of natural hazard risk analysis and decision making under uncertainty, and (iv) strengthen the competitive advantage of UK-based consultants internationally. The FoRUM project: 1. Transfer knowledge and skills about flood risk analysis - We will consolidate the advances in recent years, including the approaches to the incorporation of infrastructure failure, spatial coherence with storm conditions and the interactions between channel and floodplain dynamics. We will explore the relationship between top-down and bottom-up models and opportunities for the strengths of one to be used to compensate for the weaknesses of the other. In doing so we will highlight recognized limitations and key uncertainties. 2. Transfer knowledge and understanding about investment planning under conditions of future change and regional/local implications - We will consolidate recent advances in investment planning and the approaches adopted at national and regional levels. We will compare and contrast the techniques developed through initiatives such as FRMRC and the Agency sponsored Adaptive Capacity project and long-term Investment studies with those underdevelopment in the Netherlands and within leading corporations (e.g. RAND, World Bank). We will help stakeholders access the latest thinking and techniques to support investment planning and set the approaches being adopted in the UK in the context of wider international practice. 3. Promote a better understanding of the credibility of national estimates of risk -Through the use of case studies, we compare and contrast risk estimates provided at national (through the National Flood Risk Assessment) with those provided at a more local levels (through best practice local analysis). This will enable us to explore the credibility of the analysis at different scales and the uncertainties that users should acknowledge.

More frequent intense rainfall events, associated with climate change, increase the likelihood of shallow slope failures that lead to costly disruption of road and rail journeys, with risk to life and property. There have been recent slope failures adjacent to transport corridors in the UK, sometimes disrupting important road and rail routes for days. Vegetation has a stabilising effect on slopes: Plant root systems interlock with the soil, increasing its stiffness and strength. Uptake of water by root systems dries the soil profile, again increasing soil stiffness and strength. However, engineers need to be able to predict the combined root reinforcement and soil drying effects on slope stability, so that vegetation management can be used proactively to decrease the probability of slope failure. Vegetation has numerous benefits over conventional hard-engineering solutions, in terms of burying carbon in the soil, enhancing biodiversity, and improving the aesthetic quality of the environment for society. This project will develop and test a quantitative coupled hydro-mechanical model for the in-service and ultimate-failure performance of slopes planted with vegetation. Rooted-soil represents an innovative sustainable construction material, with distinct mechanical and hydrological properties, that can be used in geotechnical systems. The model will be applicable to both slopes covered with natural vegetation and slopes where vegetation and soil have been chosen and managed according to engineering principles. The validated model will provide a clear framework for assessment and remediation of slopes with potential for reducing economic and carbon costs. The model will be developed within a multi-scale continuum modelling framework. It will build on knowledge of the elemental components of the system, working from individual soil-root interaction, to continuum soil-root system, and to complete slope, incorporating spatial variability of materials. Modelling will be informed by X-ray CT imaging of the 3-D deformation of rooted soil undergoing shear, using the micro-VIS facility at the University of Southampton, and by field data from slopes containing established vegetation. Predictions of slope performance will be validated against scaled-slopes in the Dundee geotechnical centrifuge under different rainfall regimes. The geotechnical centrifuge enables the testing and monitoring of small-scale slopes containing roots at realistic stresses, which can be manipulated until the slopes ultimately fail. Template guidelines will be produced for a manual of combinations of plant species, soils and management schemes for optimum performance of designed soil-plant systems suited to emerging climatic conditions. Example data will also be included to allow cost-benefit analyses when designing for slope improvement using vegetation. The potential to translate research findings into related areas will be investigated (e.g. river banks, sand dunes, flood embankments, agricultural and amenity systems). We will engage with an important group of Project Partners, representing key industrial sectors and infrastructure owners, to facilitate the rapid adoption of research findings.