IAP-24-116

Sustainable Flood Management: Feasibility and Effectiveness of Catchment Scale Nature-based Solutions for Flooding and Biodiversity Restoration

Flooding, and its management, cost the UK £2.2billion per year. Many locations across the UK now experience compound flood risks, whereby risks associated with fluvial (river) and surface water (pluvial) flooding interact. Under current climate change and economic pressures, flood management policy is shifting from entirely flood defences to broader management strategies which involve holistic, multi-benefit and integrated approaches. This includes “Natural Flood Management” or “Nature based Solutions” (NbS) which aim to restore the natural resilience of catchments and cities to store water and slow the flow. Catchment-wide solutions often include tree planting, setting aside upstream agricultural land and soil management. In cities, sustainable urban drainage systems (SuDS) can be used to manage surface water drainage and include rain gardens, green roofs and swales.

This PhD will focus on the flood risk problem in Musselburgh, near Edinburgh, that has recently planned a flood protection scheme, and the wider River Esk catchment. Musselburgh has been identified by SEPA as a “Potentially Vulnerable Area” under the Flood Risk Management Act Scotland (2009). Major floods have occurred historically in 1927, 1948, 1966, 1990 and 2000, with 900 properties at flood risk from the 1 in 200-year return period flood event. The town also experiences surface water flooding from sub-surface sewer network capacity being exceeded, especially during high river flows
However, despite gaining popularity with policy makers and flood action groups, a lack of evidence on the effectiveness of Nature based Solutions and advice regarding the implementation of these innovative approaches are limiting its uptake.

This project will look at the interactions between the different sources of flooding (river, surface water, sewer flooding) and determine how each are managed. Particular questions of interest include:

– How do floods generated upstream in catchments impact on surface water floods in urban areas downstream?
– How can NbS in the wider catchment be combined with NbS in the urban areas themselves to mitigate both types of floods?
– How does the positioning of NbS impact upon their local and catchment scale benefits?
– What are the benefits for biodiversity of NbS in catchments and urban areas?
– How do NbS and traditional engineering approaches to fluvial flood management e.g. walls, embankments interact?

This project will work in partnership with the Forth Rivers Trust and other interested catchment stakeholders to develop practical, applied understanding of the above questions.

This project will utilise a mixed methods approach, combining field monitoring, numerical modelling and stakeholder engagement.

Field trials will seek to form a process-based understanding of how individual NbS features function in terms of flood protection and biodiversity restoration, for example using a wide range of soil property tests to study role of agricultural management/urban SuDS in flood mitigation and quantify scale dependency and similarity of processes between different types of NbS.

Numerical modelling, hydrological, hydraulic and ecological models, will be used to upscale the results to the larger catchment scale and also to compare and test different “What if” scenarios. This will evaluate how the spatial positioning of NbS can be optimised to mitigate both types of flooding and restore biodiversity.

Finally, the research student will be able to engage with the stakeholders in this real time flood management project, the Musselburgh Flood Protection Scheme, and consult with a large number of environmental catchment manager stakeholders to understand the factors which govern what type of NbS features are popular and what measures could be put in place to overcome barriers of implementation. Potential methods of engagement could include, but are not limited to, questionnaires and focus groups.

Year 1

General research skills training (e.g. literature reviewing, project management, working with stakeholders, development of experimental and sampling design, training needs assessment (e.g. statistical courses)).

Undertake a comprehensive literature review and develop detailed project objectives, particularly around which NbS interventions will be focussed upon, and design monitoring/modelling experiments to test their effectiveness and assess the multiple benefits.

Year 2

Continue field monitoring of NbS interventions and develop models for larger scale assessment of the multiple benefits and their effectiveness.

Year 3

Finalise data collection and analysis. Further statistical training. Work closely with stakeholders to ensure key messages are translated into practice and policy. Conference attendance to present interim results.

Year 3.5

Thesis writing and journal publications

Skills development will be supported through IAPETUS specific provision, HWU and Stirling Univ provision, and external courses. Example courses include: statistical analysis with R, media training; insights to industry; leadership skills; conference skills (e.g., networking, poster and oral presentation skills); Geographic Information Systems (GIS); and grant writing.

In addition to the core training provided by IAPETUS, the student will undertake specific training on numerical modelling through dedicated courses arranged by HR Wallingford and the Environment Agency. They will also attend a 5 day Annual Catchment Science Summer School, led by internationally leading hydrologists. Further training opportunities will be accessed through the British Hydrological Society. The student will get the opportunity to present their research at a range of national and international conferences, to build communication and networking skills. The student will be a member of the Nature based Solutions research group at Heriot Watt, which runs a series of seminars and training workshops.