Experimental and numerical simulation of water movement in soil

Zhu, Lei; Therrien, René; Yang, Jinzhong; Zhou, Qing

doi:10.1680/wama.10.00056

Cited by 3 publications

(2 citation statements)

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“…Study of the characteristic values of the wetted pattern in soils under micro‐irrigation point source percolation is a precondition and foundation for properly designing an irrigation system and managing moisture in cropland. Scholars throughout the world have conducted many theoretical and experimental studies on water and salt distribution under point source irrigation (Clothier et al ., ; Meshkat et al ., ; Kang and Wan, ; Satyanaga et al ., ), which draw attention to the characteristic values of the wetted pattern in soils under point source percolation (Khan et al ., ) and the influence of discharge rate of drippers, irrigation amount, initial water content and soil type on soil water dynamics (Novak and Knava, ; Kanzari et al ., ; Lei et al ., ; Chen and Feng, ) as well as water and salt movement in the root zone.…”

Section: Introductionmentioning

confidence: 99%

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

Han

Yang

et al. 2015

Irrigation and Drainage

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The application of superabsorbent polymers (SAPs) in agriculture can enhance water use efficiency and ease water shortage in agriculture. In this study, by applying SAPs to the middle layer of the soil root zone, the effects of SAPs on moisture distribution during infiltration and evaporation under the condition of point source irrigation were investigated. The results show that during infiltration, the wetting front formed an accident change zone in the horizontal direction; in the bottom layer, the horizontal infiltration rate is greater than the vertical infiltration rate due to the effect of SAPs from the middle layer; the soil water content in the middle layer increased remarkably by 23.6%, higher than that in the surface and bottom layers; during evaporation, the soil water content changed significantly in the surface layer due to strong evaporation on the surface, it was largest and quite even in the SAP-soil mixture layer, and decreased the least in the bottom layer due to water storage in the mixture layer. Therefore, SAP application in the crop root layer is helpful to conserve soil water content in the crop root zone, inhibit evaporation of soil water in the lower layer and facilitate moisture conservation. RÉSUMÉ L'application de polymères super-absorbants (SAP) dans l'agriculture peut améliorer l'utilisation de l'eau et faciliter la gestion de la pénurie d'eau dans l'agriculture. Nous avons étudié les incidences d'un SAP appliqué sur la couche médiane de la zone racinaire d'un sol sur l'évaporation et l'infiltration au droit d'un goutteur d'irrigation. Les résultats montrent que lors de l'infiltration, le front d'humectation subit un accident dans le sens horizontal; dans la couche inférieure, le taux d'infiltration horizontal est supérieur à la vitesse d'infiltration verticale sous l'effet du SAP de la couche centrale; la teneur en eau du sol dans la couche intermédiaire a augmenté de 23.6%, supérieure à celle de la surface et des couches inférieures; au cours de l'évaporation, la teneur en eau du sol a changé de manière significative dans la couche de surface en raison d' une forte évaporation; la variation a été la plus importante dans la couche de mélange SAP-sol, et la diminution de teneur en eau a été la plus petite dans la couche inférieure en raison du stockage d'eau dans la couche avec SAP. Par conséquent, l'application de SAP dans la zone racinaire est utile à y conserver l'humidité du sol et à inhiber l'évaporation de l'eau dans la couche inférieure.

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Section: Introductionmentioning

confidence: 99%

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

Han

Yang

et al. 2015

Irrigation and Drainage

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“…The second paper (Lei et al, 2012) deals with non-uniform groundwater flows, focusing on the effects of preferential channels on flow dynamics. These channels are formed by soil macropores and fractures, such as worm holes and root paths, enlarged by the flowing water.…”

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confidence: 99%

Editorial

Crosato¹

2012

Proceedings of the Institution of Civil Engineers - Water Manag

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This issue of Water Management presents scientific findings that increase the understanding of water flows and contribute directly or indirectly to the management of water resources. The first two papers deal with aquifer pollution and sub-surface water flows while the final two papers look at water flows in regulated rivers. The issue closes with a discussion on the effects of bedforms on river channel roughness and on the relative consequences for the prediction of water levels.Numerical modelling has become the dominant tool for scientific investigations in water-related issues. In line with this, the works provide improvement and validation of existing numerical models or advice for good modelling practice.The first paper (Ahmed and Chen, 2012) analyses the effects of tide-induced water table fluctuations on contaminant sorption in beach aquifers. Near-shore groundwater pollution occurs because of the development of coastal areas, where sources of contaminants include solid wastes and the use of fertilisers and pesticides for agriculture. Once spilled on land, the contaminants move gradually seaward, transported by the sub-surface flow, negatively affecting the quality of coastal waters. The paper focuses on the fate processes of naphthalene, a contaminant that binds itself to solid particles. To reproduce these processes, the authors combined a numerical model for water flow with a model for the transport of pollutants. They investigated both equilibrium and rate-limited sorption in coarse sand under fluctuating and constant water table conditions. The results show that the tidal effect depends on the distance between spill location and shoreline, as well as on the partition coefficient and the rate of mass transfer.The second paper (Lei et al., 2012) deals with non-uniform groundwater flows, focusing on the effects of preferential channels on flow dynamics. These channels are formed by soil macropores and fractures, such as worm holes and root paths, enlarged by the flowing water. The authors performed a number of field experiments irrigating a silty-clayey soil with water containing an iodide tracer. Clear preferential flow channels formed in the soil as a response to the large amounts of irrigation water. Numerical simulations of the experiments were undertaken to verify the performance of a hydrogeosphere model simulating soil water content and the dynamic process of infiltration under non-uniform conditions. The comparison with a model based on a continuous medium shows the importance of incorporating soil fractures for the modelling of sub-surface water flows.The third paper (Xia et al., 2012) deals with the modelling of unsteady flow in large lowland rivers. A two-dimensional hydrodynamic model incorporating a procedure for wetting and drying of grid cells is tested against field data of man-made floods in the braided reach of the lower Yellow River (China). The model is based on the finite-volume method on unstructured triangular grids. The results show that wetting and drying of grid cells can impr...

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Experimental and Numerical Investigations of Influence on Overland Flow and Water Infiltration by Fracture Networks in Soil

Zhu

Fan

et al. 2018

Geofluids

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Preferential flow is common in clay or expansive clay soils, involving water bypassing a large portion of the soil matrix. Dye tracer experiment and numerical modeling are used to simulate the surface runoff and subsurface preferential flow patterns influenced by the soil fracture network of a relatively steep hillslope system (slope angle equals to 10 degrees). The result of the experiments indicates that part of the water is infiltrated through cracks, leading to the delay of the initial runoff-yielding time and reduction of the discharge of the surface runoff. The soil water flow is mainly in the matrix when the intensity of precipitation is low. With the increasing of precipitation, soil water movement may become in the form of preferential flow through cracks. In addition, the nonuniformity of soil water infiltration and the depth of the average water infiltration increase as the precipitation intensity increases. To this end, the complete coupling model was established by using the surface-matrix-crack (SMC) model to simulate water flow within discrete fracture as well as to simulate water flow in the soil matrix based on the concept of dual permeability using the traditional Richards' equation. In this model, the "cubic law" of fluid motion in cracks within smooth parallel plates and the two-dimensional diffusion wave approximation to Saint-Venant equations with momentum term ignored (two-dimensional shallow water equations) were used. The model divides soil water infiltration into two forms and uses the overall method to calculate the exchange of water between the crack networks and matrix regions as well as the exchange water between surface runoff and infiltration water. Results indicate that the SMC model has better performance compared with the traditional equivalent continuum model when those models are used to simulate the surface runoff movement and the soil water movement in the presence of cracks.

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Experimental and numerical simulation of water movement in soil

Cited by 3 publications

References 17 publications

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

Editorial

Experimental and Numerical Investigations of Influence on Overland Flow and Water Infiltration by Fracture Networks in Soil

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