A Systematic Review and Meta-Analysis on Downstream Dam-Induced River Channel Adjustment

This is the first study on the effects of the dam on channel morphology the downstream of dam on a global scale with a systematic review and meta-analysis approach. This study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Therefore, the SCOPUS and Web of Science databases were searched using the Boolean operators ‘AND’ and ‘OR’ combined with keywords related to the subject area. All of the papers were in English and published up to 2023. Ultimately, 76 papers were evaluated for systematic review (qualitative analysis) and only 6 papers for meta-analysis (quantitative analysis). Results showed that the number of published papers has increased over time. In terms of channel adjustment, channel width decreased in the post-dam period, with narrowing and incision dominating in the downstream reaches. Meta-analysis showed that the dam has a moderately negative effect on channel width. Understanding these changes on a global scale can increase awareness of the impacts of dams on channel adjustment and their consequences.