Dynamic Simulation on Hydraulic Characteristic Values
of Overland Flow¹

X. T. Fu, L. P. Zhang, X. Y. Wu, X. Y. Wang, and H. S. Zhang

Zijingang Campus of Zhejiang University Hangzhou, 310058, China

Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Hangzhou 310029, Zhejiang Province, China

Ministry of Education, Key Laboratory of Polluted Environment Remediation and Ecological Health, Hangzhou 310029,
Zhejiang Province, China

College of Environmental and Resource Science, Zhejiang University Hangzhou 310029, Zhejiang Province, China

E-mail address: lpzhang@zju.edu.cn

Received March 14, 2011

Abstract—The economic forest management is one of the main land use models on low hill gentle slope. In
order to investigate the soil erosion properties of bare slope under economic forest, dynamic simulation on
hydraulic characteristic values of overland flow was carried out under 0.5 mm min^–1, 1.2 mm min^–1 and 1.8mm
min^–1 rainfall intensities. Results indicated that runoff shear stress increased with increasing of slope length and
their relationship can be described by quadratic equation. There were abnormal points at the length of 4 m and
5.5 m under rainfall intensity of 1.8 mm min^–1. The shallow flow was pseudo-laminar flow under 0.5 mm min^–
1, 1.2 mm min^–1 and 1.8 mm min^–1 rainfall intensities, and the runoff at upslope was sluggish flow then changed
to torrential flow at downslope with increasing of slope length. Critical Reynolds number varied from sluggish
flow to torrential flow with 1.8 mm min^–1 rainfall intensity and was more than that under 0.5 mm min^–1. Rey-
nolds number can be estimated by power function of slope length. And there was a positive correlation between
runoff shear stress and both Froude number Fr and Reynolds number Re. We hope this study can provide sci-
entific gist for soil erosion control under economic forest.

Keywords: overland flow, shear stress, Reynolds number, Froude number

DOI: 10.1134/S0097807812040057

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