NFM includes a broad range of techniques, some of which deliver real benefits for biodiversity and allow natural ecological processes to become re-established. Others, such as creating 'woody debris dams'-barriers artificially constructed from tree trunks and branches in watercourses to slow the flow of water- have fewer benefits, although they may be good for some species. Dadson et al.  concluded that 'the hazard associated with small floods in small catchments may be significantly reduced' by NFM techniques. However, they noted that the most extreme flood events may overwhelm any risk management measures, and failed to find clear evidence of NFM reducing flood risk downstream in large catchments.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report