日本地球惑星科学連合2021年大会

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[E] 口頭発表

セッション記号 M (領域外・複数領域) » M-GI 地球科学一般・情報地球科学

[M-GI30] Near Surface Investigation and Modeling for Groundwater Resources Assessment and Conservation

2021年6月4日(金) 15:30 〜 17:00 Ch.12 (Zoom会場12)

コンビーナ:Jui-Pin Tsai(National Taiwan University, Taiwan)、谷口 真人(総合地球環境学研究所)、Ping-Yu Chang(National Central University)、座長:Jui-Pin Tsai(National Taiwan University, Taiwan)、Shao-Yiu Hsu(National Taiwan University)

15:30 〜 15:45

[MGI30-01] Monitor the clogging evolution and infiltration process in a meso-scale lysimeter

★Invited Papers

*Shao-Yiu Hsu1、Jui-Hsiang Lo1、Qun-Zhan Huang1、Yi-Zhih Tsai1、Jung-Dung Lee1 (1.National Taiwan University)

キーワード:effective hydraulic conductivity, old-new water interaction, soil temperature

In paddy fields or bioretention ponds, clogging occurs when surface water carrying suspended fine grains infiltrates into soils and forms a low permeability soil layer. The clogging layer significantly reduces the infiltration rate and could induce unsaturated zones and preferential flows. In this study, based on Darcy's law for layered soil, we developed a simple 1D equation to show the relationship between the clogging location and the soil water pressure head under different boundary conditions. In a vertical 1D domain, the soil water pressure response head to a decline in the adjacent groundwater level can indicate the occurrence and location of the clogging layer, even the unsaturated zone induced by the clogging layer. We analyzed a series of pressure data measured via a tensiometer installed in a meso-scale lysimeter during steady infiltration experiments under different clogging conditions. The data revealed the clogging development at the bottom of the lysimeter and its influence on the effective hydraulic conductivity evolution. In addition, we performed the unsteady infiltration experiments in the lysimeter (single layer) under flooding and uniform rainfall boundary conditions. The changes in water contents and soil temperatures at different locations were measured to show the infiltration front and old-new water interaction. The results show that the infiltration front was mainly comprised of old water, and its velocity could be increased due to air compression.