SOIL Studies

SOIL Studies

2021, Vol 10, Num, 2     (Pages: 046-055)

Simulation of Runoff and Sediment in a Water Repellent Soil under Different Rainfall Intensity

Reyhanehsadat MOUSAVİZADEH 1 ,Sayyed-Hassan TABATABAEİ 2 ,Negar NOURMAHNAD 3 ,Sinan ARAS 4

1 Department of Water Engineering, Shahrekord University, Shahrekord, İran
2 Department of Agriculture, Payamenoor University, Tehran, İran
3 İran, Department of Agriculture, Payamenoor University, Tehran, İran
4 International Agricultural Research and Training Center (IARTC), İzmir, Turkey

DOI: 10.21657/topraksu.700846
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The impact of rainfall intensity and soil water repellence (SWR) on runoff generation and soil erosion are not fully understood. These two factors affect runoff and the related sediment. In this paper, a physical model, `Advanced Hydrological Investigations` (AHI) was employed to simulate runoff and sediment yield under different degree of hydrophobicity level also in respect with different artificial rainfall intensities. A sandy loam soil was artificially hydrophobized using different concentration of stearic acid to achieve five degrees of repellence (hydrophilic as the control). On the other hand, these five levels of artificial rainfall intensity were considered as an artificial rainfall in the model and finally 25 treatments were tested. The results showed an increase in runoff volume, decrease in sediment yield, and decrease in deep percolation volume and decrease in time of concentration by increasing hydrophobicity. The higher SWR level, the lower sediment yield. It was recorded 2 gr soil loss in extreme repellent soil under 80 l/h rainfall intensity in compare with control treatment of this situation (6.5 gr soil loss). Possible explanation of sediment reduction in hydrophobic soil, could be aggregate stability in hydrophobic treatments which is positively related with organic matter content. Sediment reduction in higher degree of SWR could be considered as soil management policy in arid and semi-arid region.


Keywords : Hydrophobicity, Runoff coefficient, Deep percolation, Soil management, Arid and Semiarid region