Quantifying the Synergies and Trade-Offs of Nature Based Solutions between flood management and biodiversity restoration

Overview

Flooding, and management, cost the UK £2.2billion per year. Under current economic pressures, flood policy is shifting from entirely flood defences to broader management strategies. This includes Natural Flood Management (often also denominated Nature Based Solutions (NBS)) which aims to restore the natural functioning of catchments to store water and slow the flow. Examples of NBS, shown in the figure here presented, include tree planting, leaky dams and river restoration, along with agricultural land management. These work with hydrological processes, including increasing infiltration of rainfall into the soil, storing water on the floodplain and increasing the flow resistance to flow within the channel to attenuate the flood peak (taking the top of the peak). These interventions also have multiple benefits for other ecosystem services such as biodiversity, water quality and carbon sequestration.

However, despite gaining popularity with policy makers and flood action groups, a lack of evidence on its effectiveness and advice about how to go about implementing such an innovative approach are limiting its success.

There are two gaps in current knowledge relating to the effectiveness of NBS. First, at the intervention scale, we do not have a full understanding of how much the natural processes which are modified by the features do alter ecosystem service provision. Second, at the larger sub-catchment scale, we have limited knowledge of how the effect of the interventions combine together and propagate through the river system. The importance of how sub-catchments interact in terms of tributary synchronicity is essential to understand in terms of larger scale scheme design (Pattison et al., 2014). Furthermore, there may be synergies and trade-offs between the different ecosystem services which need to be considered at the landscape scale.

This project aims to develop guidance on how NBS schemes can provide the optimum benefits in terms of ecosystem services at the catchment scale. The research will be focussed on the Allan Water Restoration project working with a wide range of stakeholders.

Objectives

  1. Carry out laboratory experiments and field trials to determine how interventions, e.g. leaky dams, channel restoration, effect different ecosystem services.
  2. Develop models to upscale these impacts to the catchment scale.
  3. To evaluate the synergies and trade-offs between different ecosystem services at the intervention and catchment scales.

Methodology

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, for example using a wide range of soil property tests to study role of agricultural management in flood mitigation, and temporal surveys of freshwater ecology.

Numerical modelling will be used to upscale the results to the larger catchment scale and also to compare and test different “what – if” scenarios.

Finally, the appointed student will be a part of the wider Allan water River Restoration Project, will consult with a large number of environmental catchment management stakeholders to understand the factors which govern the different types of natural flood management features are effective/popular and what measures could be put in place to overcome barriers of implementation. This would be achieved through a series of questionnaires and focus groups.

Project Timeline

Year 1

Undertake a comprehensive literature review and develop detailed project objectives, particularly around which NBS interventions will be focussed upon, and design 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. Draft initial manuscripts.

Year 3

Finalise data collection and analysis. Work closely with stakeholders to ensure key messages are translated into practice. Continue to draft scientific manuscripts.

Year 3.5

Thesis Writing. Submission of final scientific manuscripts.

Training
& Skills

In addition to the Core training provided by IAPETUS2 and relevant general skills training available at the supervisory team institutions, the student will undertake specific training on numerical modelling through dedicated courses arranged by HR Wallingford and the Environment Agency. The student 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 Water Group at Heriot Watt, which run a series of seminars and training workshops.

References & further reading

Pattison I, Lane SN. (2012). The link between land use management and flood risk: a chaotic conception?, Progress in Physical Geography, 36, 72-92

Pattison I, Lane SN, Hardy RJ, Reaney SM , (2014), The role of tributary relative timing and sequencing in controlling large floods, Water Resources Research, 50, 5444-5458.

Jakubinsky et al 2021. Managing floodplains using nature based solutions to support multiple ecosystem functions and services. Wiley Interdisciplinary Reviews: Water, 8(5), p.e1545.

Further Information

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