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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #385032
Research Project: Computational Tools and a Decision Support System for Management of Sediment and Water Quality in Agricultural Watersheds

Location: Watershed Physical Processes Research

Title: Effects of raindrop impact on the resistance characteristics of sheet flow

Author
item SHEN, ENSHUAI - Indian Institute Of Soil And Water Conservation (IISWC)
item LIU, GANG - Indian Institute Of Soil And Water Conservation (IISWC)
item JIA, YAFEI - University Of Mississippi
item DAN, CHENXI - Indian Institute Of Soil And Water Conservation (IISWC)
item A.M.ABD ELBASIT, MOHAMED - Agricultural Research Council Of South Africa
item LIU, CHANG - Indian Institute Of Soil And Water Conservation (IISWC)
item GU, JU - Indian Institute Of Soil And Water Conservation (IISWC)
item SHI, HONGQIANG - Indian Institute Of Soil And Water Conservation (IISWC)

Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2020
Publication Date: 11/18/2020
Citation: Shen, E., Liu, G., Jia, Y., Dan, C., A.M.Abd Elbasit, M., Liu, C., Gu, J., Shi, H. 2020. Effects of raindrop impact on the resistance characteristics of sheet flow. Journal of Hydrology. 592:125767. https://doi.org/10.1016/j.jhydrol.2020.125767.
DOI: https://doi.org/10.1016/j.jhydrol.2020.125767

Interpretive Summary: Soil erosion is one of the major problems in agriculture, deteriorating farming land and pollute water resources. Raindrop splash plays an important role in detaching soil from land surface. This study revealed that raindrops can also impact the surface runoff, disturbing the flow structure and increasing the flow resistance. Multiple experiments have been conducted to collect a wide range of data and extract empirical relationships between rainfall intensity, runoff depth, Reynolds number and flow resistance coefficients. The study improved our understanding to hill-slope hydrological processes, and provided measured data and empirical relationships for hydrological and water resource engineers to analyze and simulate soil erosion processes for batter accuracy.

Technical Abstract: Raindrops impact (RDI) can disturb the flow structure of sheet runoff and thus change the flow resistance. In this study, multiple experimentally simulated rainfalls were applied on a flat and smooth flume with variable slopes. To identify the RDI effect, one half of the data was collected with the flume covered by a gauze screen near runoff surface. Comparisons of results indicated that RDI increased the flow resistance, reduced flow velocity and increased flow depth. Darcy-Weisbach resistance and Manning coefficient decreased in the slope range 2–12%, and kept almost constant in higher slope range. Corresponding approximately to 12% slope, Reynolds number, Re = 800 appears to be a critical value separating the laminar and turbulent flow regime under rainfall conditions. Empirical equations relating Darcy-Weisbach resistance coefficient and Manning coefficient to Reynolds number and rainfall intensity were obtained. In addition, empirical equations of the incremental resistance, due to RDI were established for laminar flows. This study revealed some aspects of RDI in the rainfall-runoff hydrologic processes.