Influence of turbid flood water release on sediment deposition and phosphorus distribution in the bed sediment of the Three Gorges Reservoir, China

Tang, Xianqiang; Li, Rui; Wu, Min; Zhao, Weihua; Zhao, Liangyuan; Zhou, Yinjun; Bowes, Michael J. ORCID: https://orcid.org/0000-0002-0673-1934. 2019 Influence of turbid flood water release on sediment deposition and phosphorus distribution in the bed sediment of the Three Gorges Reservoir, China. Science of the Total Environment, 657. 36-45. https://doi.org/10.1016/j.scitotenv.2018.12.011

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Official URL: https://doi.org/10.1016/j.scitotenv.2018.12.011

Abstract/Summary

Excessive phosphorus (P) loading was identified as an urgent problem during the post-Three Gorges Reservoir (TGR) period. Turbid water with high suspended sediment loads has been periodically released during the flood season to mitigate sediment deposition in the TGR, but limited attention has been paid to its effect on the distribution of P in bed sediment within the reservoir. In this study, field surveys, historical monitoring data related to sediment deposition, and physiochemical properties and the fractional P content in the mainstream surface sediment and representative column sediment, were used to investigate the effect of turbid flood water release on P distribution in bed sediment. The results revealed that turbid flood water release could discharge approximately 20% of the suspended sediment inflow entering the TGR. Additionally, both the particle size of the inflow sediment and suspended sediment flux tended to decline, and the deposited sediment volume tended to constantly increase in the TGR at a rate of 0.117 billion tonnes per year between 2004 and 2016. The median particle size (MPS) was larger for surface sediment obtained in the flood season than for that obtained in the dry season, and the MPS tended to increase with an increase in the sediment depth from 0 to 20 cm. The total phosphorus (TP) content in sediment ranged from 2.6% to 17.5% lower in the flood water releasing period than in the non-flood water storing period. However, no consistent variation was detected for the vertical distribution of P fraction in the top 20 cm of bed sediment. Compared with lakes with slow deposition rates, the TGR showed a rapid sedimentation rate of >1.0 m/y, which mostly resulted in the uniform distribution of the surface sediment P fraction.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.scitotenv.2018.12.011
UKCEH and CEH Sections/Science Areas:	Water Resources (Science Area 2017-)
ISSN:	0048-9697
Additional Keywords:	Three Gorges Reservoir, deposition, distribution, fractional P, fine particles, reservoir management
NORA Subject Terms:	Earth Sciences Hydrology
Date made live:	14 Jan 2019 17:06 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/522015

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.scitotenv.2018.12.011

UKCEH and CEH Sections/Science Areas:

Water Resources (Science Area 2017-)

ISSN:

0048-9697

Additional Keywords:

Three Gorges Reservoir, deposition, distribution, fractional P, fine particles, reservoir management

NORA Subject Terms:

Earth Sciences
Hydrology