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| Characteristic of rainfall infiltration on Changwu Tableland |
| DIAO Jiao-Na1, 2 , XU Hua-Shua1, 3 , LI Xing1, 3 , ZHANG Liang-De4, YU Miao-Zi1, 3 |
(1.Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources, 712100,Yangling,Shaanxi;
2.Graduate University of Chinese Academy of Sciences, 100049, Beijing;3.Institute of Soil and Water Conservation,Northwest
A&F University,712100,Yangling,Shaanxi;4.Gansu Provincial Institute of Hydraulic and Hydroelectric Resesrch,730000,Lanzhou:China) |
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Abstract In order to deeply understand the mechanism of rainfall infiltration in thick soil layer on Loess Plateau, at Changwu experiment station, dynamic of soil water content in a large-scale loess columns was monitored by using TDR (time domain reflectometry), the amounts of seepage water collected at the bottom of the loess columns was also measured. The results showed that the impact of rainfall on soil water content was mainly concentrated in the depth less than 160 cm, and the impact decreased with depth. In the depth more than 240 cm, the information of rainfall peak almost disappeared. The velocity of wetting front was positively correlated with rain intensity, and negatively correlated with initial soil water content. The depth of wetting front movement was positively correlated with the rainfall and rainfall intensity. Soil water at the depth of 300 cm could be supplied by rainfall, piston flow was the main mechanism of soil water recharge in loess. The time lag of rainfall infiltration recharge to the soil water in 100-200 cm soil layer was about 15-18 d, and the time lag for 300 cm soil layer was about 30-45 d. The results could provide some useful references for understanding the mechanism of water cycle in Loess Tableland.
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Received: 09 March 2012
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