What approaches exist to evaluate the effectiveness of UK-relevant natural flood management measures? A systematic map.

NFM can be effective in several different ways owing to their multiple benefits; however, there are evidence gaps around understanding these different forms of effectiveness. This is particularly marked for studies considering transactive and normative effectiveness. Interdisciplinary studies are more likely to consider multiple forms of effectiveness. This systematic map also found that whilst 75% of studies mention future climate change in their studies, only 24.1% contain a systematic consideration of the issue through, for example, using climate change projections. NFM is also at risk of climate change (e.g. through drought) and therefore it is imperative that study designs seek to incorporate consideration of effectiveness under future climate change. Policymakers should be made aware of the lack of understanding of how NFM measures perform under future climate change.