Effects of bedform migration on nutrient fluxes at the sediment–water interface: a theoretical analysis

Lei Huang, Qifeng Gao, Hongwei Fang, Guojian He, Danny Reible, Dianchang Wang, Xinghua Wu

Research output: Contribution to journalArticlepeer-review

Abstract

Nutrient fluxes at the sediment–water interface are essential for water quality and aquatic ecosystems. In this study, a unified expression for the sediment nutrient flux under different controlling modes is proposed by analytically solving the first-order linear partial differential equations describing nutrient transport in the sediment layer and overlying water. In particular, the analytical expression for the sediment nutrient flux due to bedform migration is derived, and the effects of bedform parameters, water depth, and sediment size are explored. With increasing flow velocity, the controlling mode of the sediment nutrient flux changes from diffusion to sand wave motion and then bed erosion, resulting in a significant increase in the flux. The water depth and sediment size indirectly affect the sediment nutrient flux by changing the critical velocity and the dimension and migration velocity of the sand waves. The physical meaning of each term of the analytical solution can be distinguished, which is beneficial for exploring the flux exchange at the sediment–water interface in mobile beds.

Original languageEnglish
JournalEnvironmental Fluid Mechanics
DOIs
StateAccepted/In press - 2021

Keywords

  • Analytical solution
  • Bed erosion
  • Bedform migration
  • Diffusion
  • Sediment nutrient flux

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