Modelling reactive solute transport from groundwater to soil surface under evaporation
Modelling reactive solute transport from groundwater to soil surface under evaporation
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DOI：
10.1002/hyp.7555
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发表时间：
2010-02-28
影响因子：
3.2
通讯作者：
Berndtsson, R.
中科院分区：
文献类型：
--
作者：
Nakagawa, K.;Hosokawa, T.;Berndtsson, R.
进行了涉及毛细管上升和蒸发的两阶段土柱实验，以提高对盐和水从地下水到土壤表面运动的了解。总共 64 个土柱被放置在一个部分装满水的水箱中，以模拟土壤中的地下水位。将每个土壤柱分成 27 段进行分析，以分析规定时间段后液相和固相中的孔隙水和离子分布。通过一维数值模型模拟柱中的水和溶质传输行为。该模型考虑了四种阳离子（Ca2+、Mg2+、Na+ 和 K+）以溶解形式和可交换形式的阳离子交换以及一种阴离子 (SO42-) 的阴离子延迟。 Cl- 被视为保守溶质，没有延迟。液相和固相中的阳离子分布、液相中的阴离子以及体积含水量的数值结果与实验结果吻合较好。为了使模型更好地拟合这些实验结果，可能需要可变的阳离子交换容量 (CEC) 分布。当应用蒸发强度的简单计算方案时，可以更好地预测每日变化。实验开始后大约 10 天，土壤水剖面显示出稳态行为。这与数值结果和计算的速度矢量分布一致。最终模型包括阳离子交换、阴离子延迟和不饱和水流。因此，该模型可用于研究地下水主要离子浓度变化期间连续灌溉对盐积累或反应传输的影响。版权所有 (C) 2009 John Wiley & Sons, Ltd.
Two-stage soil column experiments involving capillary rise and evaporation were conducted to improve understanding of salt and water movement from groundwater to soil surface. In total, 64 soil columns were placed in a tank partly filled with water in order to mimic the groundwater table in soil. Each soil column was analysed by dividing it into 27 segments to analyse pore water and ion distribution in both liquid and solid phases after prescribed time periods. The water and solute transport behaviour in the columns was simulated by a one-dimensional numerical model. The model considers the cation exchange of four cations (Ca2+, Mg2+, Na+ and K+) in both dissolved and exchangeable forms and anion retardation for one anion (SO42-). The Cl- is treated as a conservative solute without retardation. The numerical results of the cation distributions in both liquid and solid phases, anions in the liquid phase, and volumetric water contents were in relatively good agreement with the experimental results. To achieve a better model fit to these experimental results, a variable cation exchange capacity (CEC) distribution may be required. When a simple calculation scheme for evaporation intensity was applied, better predictions in terms of daily variation were achieved. The soil water profile displayed a steady state behaviour approximately 10 days after the start of the experiments. This was in agreement with numerical results and calculated distribution of velocity vectors. The final model includes cation exchange, anion retardation, and unsaturated water flow. Consequently, the model can be applied to study sequential irrigation effects on salt accumulation or reactive transport during major ion concentration changes in groundwater. Copyright (C) 2009 John Wiley & Sons, Ltd.