Methodologies to Assess and Map the Biophysical Effectiveness of Nature Based Solutions

Abstract

AbstractNature based solutions to mitigate flooding (Natural Flood Management, NFM) can help address persistent flooding on smaller rivers that are beyond the reach of governmental grey infrastructure flood protection schemes and can also contribute to ‘green-grey’ solutions for larger rivers, recognising the many co-benefits of such nature-based solutions for nature and society. It is, however, vital that NFM interventions are carefully designed and fully tested for their effectiveness and cost-effectiveness so as not to waste valuable flood mitigation resources and to ensure that these solutions do not themselves exacerbate risks or become expensive to scale or maintain. Only through accessible, low cost approaches can this be achieved since each NFM project is usually rather small scale, low budget and unique in design and context.This chapter introduces newly developed methods for assessing the effectiveness of NFM with a focus on low-cost and open-access solutions. It highlights the opportunities and challenges of different monitoring and modelling methods, from physically-based spatial scenario models for assessing impacts of NFM interventions on flood risk to downstream assets, to using networks of low-cost environmental monitoring stations for direct measurement of effectiveness of specific interventions. Modelling is best suited to large scale strategic assessment of the optimal type, magnitude and locations of interventions, whereas assessment of the effectiveness of specific interventions is best achieved through a measurement approach or – where that is not possible – space-for-time substitution with comparable sites for which the intervention has already been applied and its effectiveness tested.