Effects of large macropores on soil evaporation in salt marshes

JOURNAL OF HYDROLOGY

卷:584

Article

Zhou, Tingzhang^1,2  Xin, Pei¹  Li, Ling³  Barry, D. A.⁴  Simunek, Jirka² 

[1] Hohai Univ, State Key Lab Hydrol Water Resources & Hydraul En, Nanjing, Peoples R China

[2] Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA

[3] Westlake Univ, Sch Engn, Hangzhou, Peoples R China

[4] Ecole Polytech Fed Lausanne, IIE, Lab Technol Ecol ECOL, Fac Environm Nat Architectural & Construit ENAC, Lausanne, Switzerland

关键词: Salt marsh;    Soil evaporation;    Macropores;    Preferential flow;    HYDRUS;   

DOI  :  10.1016/j.jhydrol.2020.124754

来源: Elsevier

【 摘 要 】

The occurrence of macropores in salt marsh sediments is a natural and ubiquitous phenomenon. Although they are widely assumed to affect pore-water flow in salt marshes significantly, the mechanisms involved and their extent are not well understood. We conducted laboratory experiments and numerical simulations to examine the effect of macropores on soil evaporation. Soil columns packed with either sand or clay and with or without macropores were set up with watertables in the columns set at different levels. A high potential evaporation rate was induced by infrared light and a fan. The results showed that in the soil with a low saturated hydraulic conductivity (and thus a low water transport capacity), the macropore behaved as a preferential flow path for groundwater to recharge the surrounding soil during evaporation. The evaporated water originated largely from the macropore rather than the soil matrix, maintaining a high evaporation rate in comparison with a homogeneous soil. This effect was more pronounced for sediments with lower hydraulic conductivities and shallower watertables. These results improve our understanding of water flow and evaporation in salt marshes with continuous macropores between the soil surface and groundwater.

【 授权许可】

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