Amplification of downstream flood stage due to damming of fine-grained rivers

Hongbo Ma, Jeffrey A. Nittrouer, Xudong Fu, Gary Parker, Yuanfeng Zhang, Yuanjian Wang, Yanjun Wang, Michael P. Lamb, Julia Cisneros, Jim Best, Daniel R. Parsons, Baosheng Wu

Research output: Contribution to journalArticlepeer-review

Abstract

River dams provide many benefits, including flood control. However, due to constantly evolving channel morphology, downstream conveyance of floodwaters following dam closure is difficult to predict. Here, we test the hypothesis that the incised, enlarged channel downstream of dams provides enhanced water conveyance, using a case study from the lower Yellow River, China. We find that, although flood stage is lowered for small floods, counterintuitively, flood stage downstream of a dam can be amplified for moderate and large floods. This arises because bed incision is accompanied by sediment coarsening, which facilitates development of large dunes that increase flow resistance and reduce velocity relative to pre-dam conditions. Our findings indicate the underlying mechanism for such flood amplification may occur in >80% of fine-grained rivers, and suggest the need to reconsider flood control strategies in such rivers worldwide.

Original languageEnglish (US)
Article number3054
JournalNature communications
Volume13
Issue number1
DOIs
StatePublished - Dec 2022

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • General
  • Physics and Astronomy(all)

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