Kinematic-wave model for soil-moisture movement with plant-root extraction

Singh, Vijay P.; Joseph, E.

doi:10.1007/bf00190190

Cited by 12 publications

(5 citation statements)

References 9 publications

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“…The kinematic wave assumption is introduced by employing a strictly convective flux law. Several researchers have investigated the kinematic wave approximation for soil water movement [e.g., Sisson, 1980;Smith, 1983;Singh and Joseph, 1993]. The topic is discussed comprehensively by Singh [1997].…”

Section: Introductionmentioning

confidence: 99%

Kinematic wave model for water movement in municipal solid waste

Bendz¹,

Singh²,

Rosqvist³

et al. 1998

Water Resources Research

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Abstract. The movement of water in a large (3.5 m 3) undisturbed sample of 22-year-old municipal solid waste has been modeled using a kinematic wave approximation for unsaturated infiltration and internal drainage. The model employs a two-parameter power expression as macroscopic flux law. The model parameters were determined and interpreted in terms of the internal geometry of the waste medium by fitting the model to one set of infiltration and drainage data. The model was validated using another set of data from a sequence of water input events. The results of the validation show that the model performs satisfactorily, but further development of the model to incorporate spatial variability would increase its capability. IntroductionThe concentration of substances such as heavy metals, nutrients, and organic compounds in landfills produces mass and energy gradients within and between the landfill and its surrounding environment. As a result, these substances will leave the landfill with gas or water flow as long as the gradients An alternative approach to describing the flow in landfills, taking the geometrical configuration into account, was suggested by Ferguson [1993]. With the primary objective of estimating the specific surface in a landfill he suggested a hydraulic model where water is present either as a static surface tension film or as a moving film on refuse particles.Because of the highly heterogeneous nature of a landfill, the flow field is not uniform. The internal geometry of a landfill facilitates fast flow in restricted channels and voids. Further, the field capacity is spatiatty variable, and some parts of the landfill therefore reach field capacity long before the entire landfill does. Water may be flowing in locally saturated regions, while the largest portion of the landfill may be well below field capacity. Channel flow, which is most significant in young deposits because of their coarser structure, has been observed in several investigations [Bengtsson et al

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Section: Introductionmentioning

confidence: 99%

Kinematic wave model for water movement in municipal solid waste

Bendz¹,

Singh²,

Rosqvist³

et al. 1998

Water Resources Research

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“…The value of d can be obtained using an infiltration model or a kinematic wave model requiring only the value of soil moisture at the surface. Following Singh [1997] and Singh and Joseph [1994], this depth can be computed as where K is the hydraulic conductivity (treated as parameter), and t is time the wetting front takes to travel the distance d .…”

Section: Testing Of the Theorymentioning

confidence: 99%

Entropy theory for movement of moisture in soils

Singh

2010

Water Resources Research

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An entropy theory is formulated for one‐dimensional movement of moisture in unsaturated soils in the vertically downward direction. The theory is composed of five parts: (1) Tsallis entropy, (2) principle of maximum entropy, (3) specification of information on soil moisture in terms of constraints, (4) maximization of the Tsallis entropy, and (5) derivation of the probability distributions of soil moisture. The theory is applied to determine the soil moisture profile under three conditions: (1) the moisture is maximum at the soil surface and decreases downward to a minimum value at the bottom of the soil column (it may be near the water table); (2) the moisture is minimum at the soil surface and increases downward to a maximum value at the end of the soil column (this case is the opposite of case 1); and (3) the moisture at the soil surface is low and increases downward up to a distance and then decreases up to the bottom (this case combines case 2 and case 1). The entropy‐based soil moisture profiles are tested using experimental observations reported in the literature, and properties of these profiles are enumerated.

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“…For describing the water fluid dynamics, the terminologies of velocity (i.e., pore water velocity) and celerity have been commonly used in various hydrological systems, such as river channels [13][14][15], estuaries [16,17], and soil porous medium [8,18,19]. Theoretically, velocity expresses mass flux, while celerity represents the speed of pressure propagation through a flow domain [20].…”

Section: Introductionmentioning

confidence: 99%

Quantify the Pore Water Velocity Distribution by a Celerity Function

Shao

Yang

et al. 2018

Geofluids

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Celerity and velocity of subsurface flow in soil porous medium are intimately linked with tracer transport, while only few current studies focused on their relations. This study conducted theoretical analyses based on a pore bundle model, under which celerity in unsaturated flow is equivalent to maximum velocity. Furthermore, under 3 models Brooks-Corey model and unmodified and modified Mualem-van Genuchten models, we used a celerity function to derive breakthrough curves aiming to quantify the advective tracer transport for 5 typical soil textures. The results showed that the celerity under near-saturated conditions can be 5 up to 100 times larger than the saturated hydraulic conductivity, and a small volumetric fraction (<15%) of pores contributed more than half of the specific discharge. First arrival time and extensive tailing of the breakthrough curves were controlled by maximum velocity and velocity distribution, accordingly. As the kinematic ratio in the Brooks-Corey model remained constantly for each specific soil, we used it to quantify the ratio of maximum tracer velocity over average tracer velocity. We also found that a bimodal soil hydraulic function (for a dual-permeability model) may result in similar soil hydraulic conductivity functions for different parameter sets, but their celerities are different. The results showed that the proposed celerity function can assist in investigating subsurface flow and tracer transport, and the kinematic ratio could be used to predict the first arrival time of a conservative tracer.

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Kinematic-wave model for soil-moisture movement with plant-root extraction

Cited by 12 publications

References 9 publications

Kinematic wave model for water movement in municipal solid waste

Kinematic wave model for water movement in municipal solid waste

Entropy theory for movement of moisture in soils

Quantify the Pore Water Velocity Distribution by a Celerity Function

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