| Permeability characteristics of layered\|heterogeneous vadose zone and influence on precipitation infiltration |
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| DOI：10.7606/j.issn.1000-7601.2020.03.01 |
| Key Words: layered\|heterogeneous vadose zone precipitation infiltration soil moisture dynamics in\|situ monitoring |
| Author Name | Affiliation | | CUI Haohao | Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, Hebei 050061, China
China University of Geosciences (Beijing), Beijing, 100083, China | | ZHANG Guanghui | Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, Hebei 050061, China | | ZHANG Yazhe | Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, Hebei 050061, China； Field Research Base for Groundwater Sciences and Engineering, Ministry of Natural Resources, Zhengding, Hebei 050800, China | | ZHANG Bing | Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, Hebei 050061, China | | FENG Xin | Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, Hebei 050061, China | | LANG Xujuan | School of Water Resources & Environment， Hebei University of Geosciences, Shijiazhuang, Hebei 050031， China |
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| Abstract: |
| The mechanism of how lithologic interfaces influence the process of infiltration, migration and redistribution of precipitation in the vadose zone is still a frontier problem to be studied. In view of the question, in\|situ experiments of natural precipitation infiltration have were carried out based on the layered heterogeneous vadose zone (6 m×4 m×5 m). The results showed that the layered heterogeneous structure had obvious influence on the infiltration process and rate of precipitation: (1) Soil water content showed the characteristics of sharp down at the stratigraphic interfaces; (2) The response of soil water content above 220 cm depth to precipitation infiltration in vadose zone was sensitive, and showed the characteristics of multi\|peak\|valley type with quick changes of water content, for instance, the variation range of water content was 22.58%~29.76% in 20~100 cm stratum and 13.74%~20.74% in 120~200 cm stratum while not sensitive below 220 cm depth and showed small fluctuation, which reflected that with the cumulative effect of multiple rainfall events, the variation range of water content in 220~400 cm stratum was 2.3%~12.15%. The variation in 430~460 cm stratum was only 2.5%~3.41%; (3) The layered heterogeneous structure blocked the movement of water (the average migration velocity of the wetting front decreased from 10.53 cm·d-1 to 0.77 cm·d-1 when it passed through the interface of sandy loam and silty sand, and from 12 cm·d-1 to 1.86 cm·d-1 when it passed through the interface of sandy loam and clay loam), when the water accumulated at the lithological interface until to overcome the resistance, it moved downwards. Due to the effect of water accumulation in the upper interface, the blocking effect of the lower layered heterogeneous structure was weakened or even eliminated. |
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