Flow hydraulic characteristics and dynamic erodibility of saline-sodic soil slopes for coastal areas under simulated rainfall conditions

ABSTRACT

Tidal flat reclamation generates several excavated saline-sodic soil slopes. However, there are limited studies on the hydraulic flow characteristics and dynamic erodibility of saline-sodic soil slopes. This study was conducted to quantify the effects of the soil bulk density (1.35 and 1.40 g cm⁻³), rainfall intensity (85, 110, and 125 mm h⁻¹), and slope gradient (11°, 22°, and 35°) on the hydraulic characteristics and soil erodibility of saline–sodic soil slopes under simulated rainfall conditions. The mean sediment loss significantly increases with the slope gradient (pr = 0.9, p < 0.01), rainfall intensity (pr = 0.6, p < 0.05), and soil bulk density (pr = 0.6, p < 0.05). The hydraulic shear stress (τ) and stream power (ω) are good sediment loss predictors for all soil bulk densities (R² = 0.4 and 0.6). The stream power equation S_L = K_ω(ω − ω_cr) outperforms both hydraulic shear stress equations [S_L = K_τ(τ − τ_cr)^3/2; S_L = K_τ(τ − τ_cr)]. In most cases, the soil erodibility exponentially increases to a maximum and then exponentially decreases (R² > 0.6). Consequently, the dynamic changes in the saline-sodic soil erodibility during a rainfall event cannot be neglected.

KEYWORDS:

• Saline–sodic soil
• sediment loss
• hydraulic flow characteristics
• soil erodibility

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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Additional information

Funding

This work was supported by National Natural Science Foundation of China through grant nos. 51679062 and 41807016, the CAS ‘Light of West China’ Program, and the first-class subject foundation of Guizhou Province (GNYL[2017]007).