Resilient Coastal Communities: Nature-based Solutions to Mitigate Compound Flood Risks

Coastal wetlands and dunes are vital natural defences that provide protection against severe storms, flooding and coastal erosion (Nepf, 2012). These ecosystems increase the coastal resilience of cities situated along the coast whilst offering additional ecosystem services such as carbon storage, habitats and public amenity value (Barbier et al., 2011; Hansen & Reidenbach 2012). As well as coastal flooding, many UK cities are at risk of surface water and fluvial flooding. In particular, mainland Scotland has almost 10,000 kilometres of coastline and over 50 coastal localities which are within 2 kilometres of the coast and have populations greater than 1,000 people. Compound flooding arises from storms causing concurrent extreme meteorological tides (i.e. storm surges and waves) and precipitation events (Bevacqua et al. 2020) which can cause a variety of cascading, propagating impacts. Compound flooding can severely affect densely populated low-lying coastal areas and affect emergency responder travel times/accessibility (Green et al. 2017) and damage critical infrastructure utility systems (Yin et al., 2022). The impacts of compound flooding are expected to worsen with climate change, resulting in these events becoming more frequent, severe and costly.

Despite growing recognition of the importance of natural solutions in flood risk management, there is a gap in our understanding of how urban green infrastructure (UGI) and coastal green infrastructure (CGI) can effectively protect urban areas from compound flooding events caused by coastal, fluvial, and surface water flooding. Further, the spatial and temporal scales over which Nature-based Solutions (NbS) are effective is place and scale dependent. This PhD will couple field-monitored data with numerical modelling techniques to upscale the influence of NbS interventions and to determine the effectiveness of sustainable, holistic approaches to flood risk management in areas at risk from multiple flood typologies.

This PhD project will involve systematic review of compound flood risk assessments in Scotland and will focus on the role of urban green infrastructure (UGI) and coastal green infrastructure (CGI) to protect cities from compound flooding events caused by coastal, fluvial and surface water flooding. There will be a strong focus on the collection, analysis and interpretation of field-monitored data to understand compound, cascading flood hazards and there is scope to complement and upscale field approaches using hydraulic-hydrological modelling approaches to understand the impact of NbS at larger scales and under different probabilistic scenarios. Network analysis approaches may be employed to understand the influence of cascading flood impacts on emergency responders and critical infrastructure, which may be coupled with live sensor data to develop early-warning systems.

Field observations and model runs will provide novel insights into the influence of vegetation and the interplay of biological, ecological and physical processes in the evolution of vegetated coasts and at-a-source urban Sustainable Drainage Systems (SuDS) interventions. The outcome of the study will improve our predictions of the collective performance of vegetated coasts and urban GI at mitigating against compound flooding and provide wider ecosystem service benefits.

Although this PhD will focus specifically on compound flooding in Scotland, there will be opportunities to collaborate with international stakeholders and partners to realise the potential of NbS within different regions/climates.

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Image Captions

Figure 1: (a) Scale‐dependent feedbacks around vegetation patches in CGI; (b) vegetation along coastal sand dunes; (c) Unmanned Aerial Vehicle (UAV) in combination with Artificial Intelligence Techniques (UAV-AI to monitor biogeomorphic evolution of coastal vegetation patches and map urban topography; (d) urban GI integrated field monitoring network, used to manage local, at-source surface-water runoff.


This project will feature a combination of novel field-based research and numerical modelling approaches to upscale field-monitored datasets. The overall scope of the fieldwork and modelling elements of the PhD project are flexible, but the project may incorporate the following aspects:

• Initial scoping exercise to identify areas most at risk of compound flood risk and determine areas of low- and high- NbS adoption and potential
• Commissioning of field-based sensor systems to monitor hydrometeorological variables (i.e. soil moisture, weather and water level/velocity measurements) within urban and coastal NbS features
• Remote assessment and observation vegetation growth and hydrodynamics using drone-based UAV (Unmanned Aerial Vehicle) and Artificial Intelligence (AI) image analysis techniques
• Numerical modelling and upscaling of field observations to understand the potential of vegetated coasts and source level urban GI features to manage compound flood risk at different scales
• Impact assessment and development of GIS network analysis framework to assess risk to vulnerable locations, infrastructure and emergency service providers
• Stakeholder engagement and impact assessment on vulnerable coastal communities to quantify wider impact of NbS interventions.

Project Timeline

Year 1

• Attend core introductory induction programmes of IAPETUS2 and Heriot-Watt University
• Meet supervisory team and wider research teams at Heriot-Watt and Glasgow Universities
• Undertake research-specific start-up training and identify training opportunities/needs
• Undertake systematic literature review on coastal green infrastructure, compound flooding and methodological approaches (Project aim and objectives report)
• Use secondary data sources (i.e. SEPA Flood Maps, LiDAR and UK Climate Projection datasets) for case study location identification and scoping.
• Specific case study scoping exercises and networking with key stakeholders
• Gain clear understanding of research gaps, primary/secondary data requirements and key methodological approaches to undertaking environmental research (Methodology review)
• Undertake practical fieldwork relating to field observation, sensing and measurement.
• Production of first-year report (Mini-thesis format) and formal Departmental research seminar presentation (Oral presentation)
• Compile data sources and conduct exploratory preliminary analyses
• Attend relevant postgraduate national conference (i.e. British Hydrological Society or British Society of Geomorphology events)
• Complete preliminary literature review chapter
• Refine methodological approach of modelling and monitoring and identify key data/parameters to study

Year 2

• Refine study and undertake independent research programme, set up and commissioning field experiments
• Complete draft of methodology thesis chapter
• Submission of thesis plan with Gantt chart for completion and submission
• Begin analysis of field monitoring data

Year 3

• Continue fieldwork and modelling data analyses
• Write up of results and analysis chapter drafts
• Submission of end of year report and route to completion roadmap documentation. Formal meeting with thesis committee for official completion review
• Oral presentation of PhD research at relevant International conference

Year 3.5

Year 3.5 will focus on final thesis writing and publication of original research articles relating to the PhD research programme. The successful applicant will finalise and formally submit the completed PhD thesis and will prepare for the final viva examination. This stage will also be used to either seek follow-on postdoctoral funding relating to the PhD project or prepare the student for postdoctoral jobs within academia and/or industry.

& Skills

The successful candidate will be registered and based at Heriot-Watt University within the Lyell Center and the School of Energy, Geoscience, Infrastructure and Society in Edinburgh and will work closely with research colleagues based in the School of Geographical & Earth Sciences at Glasgow University.

The IAPETUS2 DTP programme will provide cross-disciplinary training and development opportunities, most of which will be held at Heriot-Watt University. The student will also undertake an induction programme hosted at Heriot-Watt University. Prof. Qingping Zou will act as the primary supervisor and the successful student will receive co-supervision from Dr. Daniel Green (Heriot-Watt), Professor Larissa Naylor and Dr. Martin Hurst (Glasgow). The supervisory team will jointly provide transferable research skills training (i.e. literature review, scientific writing/publication, oral presentation) and will signpost the successful candidate to relevant and timely support/training opportunities. Extensive and hands-on research-specific training relating to the fields of flood risk management, coastal geomorphology and environmental monitoring will also be provided by the supervisory team.

There will be opportunities for the student to present their research at relevant national and international conferences and to apply research in an industry context. Further, the successful applicant will be encouraged to work collaboratively with relevant stakeholders and organisations to ensure that outputs of the project are transferable and impactful.

References & further reading

Barbier et al. (2011) ‘The value of estuarine and coastal ecosystem services’, Ecological monographs, 81(2), 169 – 193.

Bevacqua et al. (2020) ‘More meterological events that drive compound coastal flooding are projected under climate change’, Nature Communications Earth and Environment, 1, 47, 1 – 111.

Green et al. (2017) ‘City-scale accessibility of emergency responders operating during flood events’, Natural Hazards and Earth System Sciences, 17, 1 – 16.

Green et al. (2021) ‘Green infrastructure: The future of urban flood risk management?’, WIREs Water, 8(6), e1560.

Nepf (2012) ‘Flow and transport in regions with aquatic vegetation’, Annual Review of Fluid Mechanics, 44, 123 – 142.

Hansen and Reidenbach (2012) ‘Wave and tidally driven flows in eelgrass beds and their effect on sediment suspension’, Marine Ecology Progress Series, 448, 271 – 288.

Yin et al. (2022) ‘Resilience of critical infrastructure systems to floods: A coupled probabilistic network flow and LISFLOOD-FP model’, Water, 14, 683.

We are looking for enthusiastic, self-reliant and self-motivated candidates with a background in Physical Geography, Environmental Sciences, Civil Engineering, Computing or related disciplines. Previous experience in field data collection, data analysis and/or soil-water-plant interactions would be advantageous.

For informal enquiries or if you are considering applying for this Studentship, please contact:
Prof. Qingping Zou (Q.Zou@hw.ac.uk) and/or Dr. Daniel Green (D.Green@hw.ac.uk).

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