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The vertical heterogeneity of soil detachment by overland flow on the water-level fluctuation zone slope in the Three Gorges Reservoir, China
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  • Ping Guo,
  • Hai Xiao,
  • Feng Gao,
  • Zijuan Li,
  • Huan Hu,
  • Qianheng Zhang,
  • Zhenyao Xia,
  • Mingyi Li,
  • Yueshu Yang
Ping Guo
China Three Gorges University
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Hai Xiao
China Three Gorges University
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Feng Gao
China Three Gorges University
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Zijuan Li
China Three Gorges University
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Huan Hu
China Three Gorges University
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Qianheng Zhang
China Three Gorges University
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Zhenyao Xia
China Three Gorges University
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Mingyi Li
China Three Gorges University
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Yueshu Yang
China Three Gorges University
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Abstract

Submersion and exposure from the operation of the Three Gorges Reservoir (TGR) can alter soil properties and plant characteristics at different elevations of the water level fluctuation zone (WLFZ), possibly influencing soil detachment capacity (Dc), but the vertical heterogeneity of this effect is uncertain. Soil samples were taken from 6 segments (5 m elevation per segment) along a slope profile in the WLFZ of the TGR to clarify the vertical heterogeneity of Dc. Scouring experiments were conducted at 5 slope gradients (17.63%, 26.79%, 36.40%, 46.63%, and 57.74%) and 5 flow rates (10, 15, 20, 25, and 30 L min–1) to determine Dc. The results indicate that the soil properties and biomass parameters of the WLFZ are strongly affected by elevation. Dc fluctuates with increasing elevation, with maximum and minimum average values at elevations of 145-150 m and 165-170 m, respectively. Linear equations accurately describe the relationships between Dc and hydrodynamic parameters. τ, ω, and E perform much better than U. Furthermore, a clear improvement is seen when using the general index of flow intensity to estimate Dc. Dc is significantly negatively correlated with MWD (p < 0.05) and organic matter (p < 0.01) but not significantly correlated with other soil properties (p > 0.05). At elevations of 145-150 m and 170-175 m, rill erodibility was greater than at other elevations. The critical hydraulic parameters were highest in the 165-170 m segments, both showing obviously fluctuation in the vertical direction of slope surface. This research highlighted the vertical heterogeneity of the soil detachment and was helpful to understand the mechanisms of soil detachment processes in the WLFZ of the TGR.

Peer review status:ACCEPTED

12 Mar 2021Submitted to Hydrological Processes
13 Mar 2021Submission Checks Completed
13 Mar 2021Assigned to Editor
15 Mar 2021Reviewer(s) Assigned
08 Apr 2021Review(s) Completed, Editorial Evaluation Pending
22 Apr 2021Editorial Decision: Revise Major
20 May 20211st Revision Received
20 May 2021Submission Checks Completed
20 May 2021Assigned to Editor
20 May 2021Reviewer(s) Assigned
05 Jun 2021Review(s) Completed, Editorial Evaluation Pending
08 Jun 2021Editorial Decision: Revise Minor
10 Jun 20212nd Revision Received
18 Jun 2021Submission Checks Completed
18 Jun 2021Assigned to Editor
18 Jun 2021Reviewer(s) Assigned
22 Jun 2021Review(s) Completed, Editorial Evaluation Pending
22 Jun 2021Editorial Decision: Accept