Measurement of the mass of soil particles transported by surface flow on which the impact of rain drops is applied

• Published in: Transactions of The Japanese Society of Irrigation, Drainage and Reclamation Engineering Vol. 1993; no. 165; pp. 23 - 32,a1
• Main Authors: Fukada, M. (Yamaguchi Univ. (Japan). Faculty of Agriculture), Fujiwara, T, Kusaka, T
• Format: Journal Article
• Language: Japanese
• Published: The Japanese Society of Irrigation, Drainage and Rural Engineering 25.06.1993
• Subjects: AGUA DE LLUVIA; EAU DE PLUIE; EROSION; EROSION HYDRIQUE; EROSION POR EL AGUA; MOUVEMENT DU SOL; MOVIMIENTO DEL SUELO; RAINWATER; SOIL MOVEMENT; WATER EROSION
• ISSN: 0387-2335; 1884-7234
• DOI: 10.11408/jsidre1965.1993.165_23

The hydraulic characteristics and the sediment of rain flow were investigated by applying artificial rainfall on a continuous flow which was not able to move soil particles. In other words, the tractive force of flow was under critical one. Also the relationship among the total mass of transported soil, rain-drop energy, water depth, mean velocity of the surface flow and diameter of the soil particles was observed. Regarding the experiment at results, the coefficient of friction of the flow was laminar, the runoff of soil particles was generated by the impact of rain drops and it reached to its the maximum values when h/Hmax was between 0.4 and 0.6 (where h means the water depth and Hmax means the maximum height of cavity, generated by the impact of a water drop) and also increases in proportion to the total energy of the rain drops (=(impact energy) ×(frequency of impact)). The experimental data could not be transformed into the non-dimensional form only by non-dimensional tractive force ΨT and non-dimensional runoff ΦL because the sediment also depends on impact energy and particle diameter. However, all of the experimental results may be explained by the other non-dimensional quantity φ(=qs (σ-ρ) gWd/(UaIV02); qs: sediment, σ: specific weight of sand particles, Ua: mean velocity of surface flow, I: rainfall intensity, Wd: sedimentation speed, V0: impact velocity of raindrop), ξ(=d/Hmax) and II 3(=h/Hmax).