Simulation of Runoff and Sediment in a Water Repellent Soil under Different Rainfall Intensity
2021
Tabatabaei̇, Sayyed Hassan
The impact of rainfall intensity and soil water repellence (SWR) on runoff generation and soil erosionare not fully understood. These two factors affect runoff and the related sediment. In this paper, aphysical model, “Advanced Hydrological Investigations” (AHI) was employed to simulate runoff andsediment yield under different degree of hydrophobicity level also in respect with different artificialrainfall intensities. A sandy loam soil was artificially hydrophobized using different concentration ofstearic acid to achieve five degrees of repellence (hydrophilic as the control). On the other hand, thesefive levels of artificial rainfall intensity were considered as an artificial rainfall in the model and finally25 treatments were tested. The results showed an increase in runoff volume, decrease in sedimentyield, and decrease in deep percolation volume and decrease in time of concentration by increasinghydrophobicity. The higher SWR level, the lower sediment yield. It was recorded 2 gr soil loss in extremerepellent 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 stabilityin hydrophobic treatments which is positively related with organic matter content. Sediment reductionin higher degree of SWR could be considered as soil management policy in arid and semi-arid region.
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