Natural flood management: assessing the barriers to wider implementation

Flood risk management (FRM) aims to reduce the likelihood and impacts of floods on society. Natural flood management (NFM) as a part of FRM aims to work with natural hydrological and morphological processes, features and characteristics to manage the sources and pathways of flood waters. It is increasingly proposed as a sustainable solution to manage recurrent flooding, both in the UK and other European countries, but significant barriers remain to its implementation. This study takes an interdisciplinary approach to identify and assess the barriers to uptake and implementation of NFM. The research has four key questions: 1) Can natural flood management impact on hydrograph characteristics? 2) To what extent is an at-risk community knowledgeable of NFM and how does this impact on attitudes? 3) What are the barriers to NFM uptake nationally and how do they apply in practice? 4) Can land manager exposure to NFM result in changes of knowledge, attitudes and behaviour? Question 1 (impacts of NFM on the hydrograph), was investigated by constructing and monitoring an experimental NFM site in Southwell, UK. This included construction of earth bunds, a stream restoration reach and large woody debris on agricultural land upstream of the town. This study focused on the impacts of runoff storage within earth bunds. However, the impacts of the scheme as a whole are also discussed. Question 2 was answered using a questionnaire, sent to all households in the selected community. For question 3, semi-structured interviews were undertaken with land managers and individuals from professional FRM backgrounds in the UK. Data were analysed using qualitative methods, including thematic coding and categorisation. For question 4, land managers interviewed previously were invited to a demonstration of the site following the implementation of the experimental NFM. Attendees were subsequently interviewed to assess whether the site visit had an impact on their knowledge and attitudes. Findings regarding question 1 (impacts on the hydrograph), show that at the slope scale a change in the peak stage relationship between the upstream and downstream loggers suggests that NFM intervention has had a positive impact in lowering peak stage during events. Moreover, storage within the bunds has reduced peak discharge during sampled events, with discharge shifting from the rising limb and peak of the hydrograph to the falling limb. Yet, the impacts on the hydrograph have been found to be limited during higher flow events, with the post NFM peak stage relationship curving towards the pre intervention linear trendline. When upscaling from the slope to the catchment scale, reductions in peak discharge became less important. Simulating the impact of a greater amount of storage at the catchment scale suggests that it could have a significant impact on discharge. For meaningful storage to be created, it is likely that more stakeholders will need to be involved across a larger catchment area. Therefore it is crucial that social barriers to uptake from multiple stakeholders are considered. Results for question 2, (community knowledge and attitudes), show that the at-risk community’s attitudes towards NFM were influenced by respondents’ knowledge of NFM and their past experience of flooding. Residents who had experienced flooding in their homes exhibited less favourable attitudes towards NFM. Meanwhile, residents with a lack of knowledge of NFM were also more likely to be unfavourable towards it. When investigating question 3, (barriers to NFM uptake), a total of 25 barriers were identified. Key ones are economic constraints for land managers, a current lack of scientific evidence to support NFM and lack of governance over long-term responsibility for NFM, which hinders future monitoring and maintenance. Practitioners were less likely to recognise other barriers noted by land managers, including cultural challenges, catchment planning concerns and lack of perceived control. After the demonstration site visit for question 4, land managers' knowledge and attitude towards NFM had improved and some were considering NFM on their land. However, the lack of governance over the maintenance of NFM was still a significant barrier to uptake, as was the financial constraints of the farm. Policy is needed to guarantee the maintenance of NFM features in the future. Also, if public good is expected from private land, then financial incentive to land managers needs to be considered, to offset losses to the farm business. The study has highlighted the importance of interdisciplinary research when insights into complex issues are sought. If NFM is to be implemented across wider catchment scales, the hydrological barriers need to be considered alongside the social barriers to uptake. It is vital for sustainability of future projects that policy makers and practitioners of FRM consider the constraints to NFM implementation identified across research disciplines