Author(s): Haojie Lai

Linked Author(s): Haojie Lai

Keywords: Sediment transport; Biofilm; Erosion; Deposition; Three Gorges Reservoir;

Abstract: Sediment in a water column provides excellent substratum for microorganism colonization, and further contributes to the formation of biofilm, which is a complex structure consisting of living microorganisms and their metabolic products known as extracellular polymeric substances (EPS). Most natural sediment is invariably covered by biofilms in rivers and lakes, which alter the physical and chemical of sediment, resulting in substantial influence on sediment transport and water ecological environment. Moreover, the sediment transport processes also play a crucial role in the development of microbial biomasses by impacts on biofilms growth. In this study, biofilm development model are presented with sediment erosion and deposition for TGR and the lower reaches below the Three Gorges, respectively. The proposed model is coupled with the hydrodynamic and sediment transport model to estimate the distribution of biofilms in TGR with the main consideration of sediment deposition. Then, the temporal distribution of biofilm was calculated by the proposed model at the lower reaches below the Three Gorges. Results show that the biomass of biofilms in the bed sediment near the river bank is significantly higher than that at the mainstream, due to the moderate sediment accumulation rate and flow resistance and the biofilms decrease significantly at the lower reaches below the Three Gorges after the operation of TGR. The proposed model can reasonably reflect interrelation between biofilms development and the processes of deb deformation, which can be further applied to provide references for the integrated management of natural aqueous systems.

DOI: https://doi.org/10.3850/38WC092019-0498

Year: 2019