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Simplified method to estimate the Green-Ampt wetting front suction and soil sorptivity with the Philip-Dunne falling-head permeameter
被引:19
|作者:
Regalado, CM
Ritter, A
Alvarez-Benedí, J
Muñoz-Carpena, R
机构:
[1] ICIA, Dept Suelos & Riegos, San Cristobal la Laguna 38200, Spain
[2] Inst Tecnol Agr Castilla & Leon, Valladolid 47080, Spain
[3] Univ Florida, Dept Agr & Biol Engn, Gainesville, FL 32611 USA
关键词:
D O I:
10.2136/vzj2004.0103
中图分类号:
X [环境科学、安全科学];
学科分类号:
08 ;
0830 ;
摘要:
Wetting front suction and soil sorptivity (S) are relevant parameters to water movement in the vadose zone. Both may be estimated with the Philip - Dunne falling-head permeameter, given the moisture increment (Delta theta) and measured times (t(med) and t(max)) during an infiltration event. Previous studies have shown that the Philip - Dunne falling head permeameter can be used for estimating saturated hydraulic conductivity (K-s), but its potential to estimate the soil's sorptivity has received little attention. We investigate the ability of the Philip - Dunne method estimate S and the Green - Ampt's suction at the wetting front, Psi, by performing a parameter sensitivity analysis, focusing on the boundary conditions that limit the search space of physically sound solutions, and studying the shape factors used in Philip's analysis to reduce the three-dimensional flux of water in the soil to one dimension. Finally, a useful approximate solution is provided that allows computing both K-s and the Green - Ampt's suction at the wetting front, Psi, ( and hence the macroscopic capillary length parameter, alpha*) from only two infiltration times, t(med) and t(max), without having to resort to such a costly measurement as the soil moisture increment, Delta theta, required by the original method.
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页码:291 / 299
页数:9
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