Application of the effective rainfall method for analyzing groundwater level variations in a landslide site in a snow-covered mountainous region

Katsura, Shin’ya; Hatada, Kazuhiro; Kimura, Takashi; Maruyama, Kiyoteru; Ikeda, Shinji; Akiyama, Kayo

doi:10.3313/jls.53.1

Cited by 3 publications

(1 citation statement)

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“…Numerous previous studies have addressed the prediction of the deep groundwater level due to rainfall [Unno et al ., 2008 ;Ito, 2018 ;Wei et al ., 2019]. There are many types of analysis methods, including analysis of groundwater level response to rainfall using effective rainfall [Unno et al ., 2008 ;Masuyama, 2009 ;Katsura et al ., 2016], conceptual models such as the tank model [Yoshimatsu, 1980 ;Enokida, 1992], and three-dimensional groundwater flow analysis based on detailed physical models [Asano et al ., 2005 ;Fujita et al ., 2014].…”

Section: Introductionmentioning

confidence: 99%

Effects of Shallow Groundwater on Deep Groundwater Dynamics in a Slow-Moving Landslide Site

YOKOYAMA

EGUSA

Ikka

et al. 2023

IJECE

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A slow-moving landslide is a mass movement that has major societal impact because of its large sediment volume. The principal cause of landslides is increased pore water pressure in deep aquifer close to the slip surface. Elucidation of the behavior of deep groundwater is critical in the stability analysis of the slowmoving landslides. Shallow groundwater, which flows through the landslide regolith, can undergo vertical infiltration and thus make a major contribution to the formation of deep groundwater, but this has not been sufficiently elucidated. The aim of the present study was to investigate the effects of shallow groundwater on the dynamics of deep groundwater in a landslide regolith. At a landslide site, with an area of 4200 m 2 , the shallow and deep groundwater levels were observed. A 1-m-depth temperature survey and groundwater quality analysis were also performed. Water budget analysis using the groundwater level showed that in the former half of a major rainfall event, groundwater that infiltrates vertically in the landslide regolith plays a central role in raising the deep groundwater level. In addition, the preferential flow from shallow to deep aquifers is suggested to be important in that infiltration. The results of this study emphasize the importance of including the preferential flow from the shallow aquifer when modeling dynamics of deep groundwater.

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