Particle size differentiation explains flow regulation controls on sediment sorting in the water-level fluctuation zone of the Three Gorges Reservoir, China

A - Papers appearing in refereed journals

Tang, Q., Collins, A. L., Wen, A., He, X., Bao, Y., Yan, D., Long, Y. and Zhang, Y. 2018. Particle size differentiation explains flow regulation controls on sediment sorting in the water-level fluctuation zone of the Three Gorges Reservoir, China. Science of the Total Environment. 633, pp. 1114-1125.

AuthorsTang, Q., Collins, A. L., Wen, A., He, X., Bao, Y., Yan, D., Long, Y. and Zhang, Y.
Abstract

The Three Gorges Dam has significantly interrupted fluvial continuity and modified the mass transfer regime
along river continuums. Flow regulation following regular dam operations drives dramatic hydrological regime shifts, which facilitates sediment dispersal in the water-level fluctuation zone over episodic inundation periods.How flow regulation modulates sediment redistribution, however, remains unclear. In this study, we depict absolute particle size composition of suspended sediment and sink sediment in the water-level fluctuation zone,and these are interpreted in the context of flow regulation controls on sediment sorting.Multiple sampling strategies
were applied at different spatial and temporal scales, to overcome limitations of labour and cost input in a
large-scale field study and to collect representative samples. The results revealed a longitudinal fining trend and seasonal variability in particle size composition for suspended sediment. Sink sediment collected fromthe water level fluctuation zone during a single summer flood event displayed a similar longitudinal fining trend, reflecting preferential settling of coarser fractions in the backwater reaches where flow velocity declines sharply. Surface sediment demonstrated a laterally coarsening trend with increasing elevations along a slope profile. Flooding duration,frequency and timing represent key factors in determining the elevation-dependent variations in the
magnitude of sedimentation and its source inputs. Relatively longer flooding duration and frequent intermediate summer floods with high suspended sediment flux are responsible for high sedimentation rates in the lower portions with distal upstream source inputs,while low sedimentation rates in the upper portions are principally associated with water impoundment and sediment produced from local bank erosion. Vertical particle size variability was observed along a sedimentary core profile, which most likely reflects seasonal differences in source supplywith contrasting particle size characteristics.Weconclude that absolute particle size differentiation explains flow regulation controls on sediment sorting in the water-level fluctuation zone of the Three Gorges Reservoir.

KeywordsFlow regulation; Hydrological continuity; Particle size; Sediment sorting; Water-level fluctuation zone; Three Gorges Reservoir
Year of Publication2018
JournalScience of the Total Environment
Journal citation633, pp. 1114-1125
Digital Object Identifier (DOI)doi:10.1016/j.scitotenv.2018.03.258
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeS2N - Soil to Nutrition - Work package 3 (WP3) - Sustainable intensification - optimisation at multiple scales
Output statusPublished
Publication dates
Online28 Mar 2018
Publication process dates
Accepted21 Mar 2018
Copyright licenseCC BY
PublisherElsevier Science Bv
ISSN0048-9697

Permalink - https://repository.rothamsted.ac.uk/item/84759/particle-size-differentiation-explains-flow-regulation-controls-on-sediment-sorting-in-the-water-level-fluctuation-zone-of-the-three-gorges-reservoir-china

Restricted files

Publisher's version

Under embargo indefinitely

4 total views
2 total downloads
0 views this month
0 downloads this month