Observations and Analysis of Vertical One-Dimensional Rainfall Seepage Flow Phenomenon

Heavy rainfall due to climate change such as global warming exceeds our expectations every year in Japan, and slope failures occur due to heavy rainfall. The heavy rain disasters in Japan tend to result in human and economic loss. Therefore, in this paper, focusing on Horton's infiltration capacity theory, we have developed a proposed formula that takes into account rainfall seepage flow when bare ground or nonwoven filters are installed. We have created an artificial slope as a slope for field experiments and installed a rain gauge and a soil moisture meter for on-site measurement. Furthermore, numerical calculations were performed based on the vertical one-dimensional seepage flow phenomenon. We compared the results of numerical analysis and on-site measurement and examined the effect of the presence or absence of nonwoven filters on the infiltration capacity in the rainfall. In conclusion, when the ground surface is bare, the infiltration capacity tends to decrease due to surface erosion of the slope and the impact of raindrops. Secondly, we are able to determine the constant of the proposed formula from the field observations. Finally, if a nonwoven filter is applied to the ground surface, it has infiltration capacity and improves the water resource recharge function compared to the case of bare ground.