Modeling effect of initial soil moisture on sorptivity and infiltration

Stewart, Ryan D.; Rupp, David E.; Najm, Majdi Abou; Selker, John S.

doi:10.1002/wrcr.20508

Cited by 52 publications

(29 citation statements)

References 35 publications

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“…(18) is the same as in other studies (Haverkamp et al, 1990;Morelsey and Khanji, 1974;Philip, 1958;Stewart et al, 2013;White and Sully, 1987) in which the first term in the second bracket on the right side of the equation was replaced by a variable representing the achievement of "capillary potential." From Eq.…”

Section: Methods Based On Constant Pressure Head Absorption (Mcpa)mentioning

confidence: 88%

An improved method for determining Brooks–Corey model parameters from horizontal absorption

Zhang

Lai

et al. 2016

Geoderma

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Low-cost, simple, rapid and accurate approaches for measuring soil hydraulic properties are of great importance in the application of hydrologic models of the vadose zone. A recently proposed method of constant-saturation absorption (MCSA) for determining Brooks-Corey (BC) model parameters is promising. However, this method has not been tested using experimental data. In this paper, measured soil-water diffusivity or soil-water retention curves (SWRCs) of 20 soil samples were used to test the reliability of MCSA. The results indicate that MCSA consistently estimated soil-water diffusivities by the Bruce and Klute method, but it substantially overestimated air-entry suctions (h d ) and thereby soil suction. A new method (MCPA) is proposed herein to overcome the problems associated with MCSA. Using the improved method, estimated SWRCs are consistent with observation. With the estimated soil hydraulic parameters, HYDRUS-1D generated very accurate simulations of the cumulative absorption curves. Compared with direct or other indirect methods, MCPA is a more accurate, low-cost, and simple method, and it is especially useful for rapid determination of SWRC for soil-water movement simulations. However, if unsaturated soil-water diffusivity is of greater concern, our results also indicate that MCSA more accurately predicts this quantity and thus should be preferred.

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Section: Methods Based On Constant Pressure Head Absorption (Mcpa)mentioning

confidence: 88%

An improved method for determining Brooks–Corey model parameters from horizontal absorption

Zhang

Lai

et al. 2016

Geoderma

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“…This reference sample was reused for each measurement at a different initial SWC. Theoretically, for homogenous soil under normal soil conditions, K fs should be independent of initial SWC, θ i (cm 3 cm −3 ; (Smith, Smettem, Broadbridge, & Woolhiser, )), whereas S f should be a non‐linear function of SWC (Stewart, Rupp, Abou Najm, & Selker, ). However, for hyper‐dry conditions (SWC < 0.02 cm 3 cm −3 ; (Moody et al, ; Moody & Ebel, )), these relations do not hold, and hyper‐dry conditions can be a source of variability (Figure ).…”

Section: Resultsmentioning

confidence: 99%

Sources of inherent infiltration variability in postwildfire soils

Moody

Martin²,

Ebel

2019

Hydrological Processes

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An automated disc infiltrometer was developed to improve the measurements of soil hydraulic properties (saturated hydraulic conductivity and sorptivity) of soils affected by wildfire. Guidelines are given for interpreting curves showing cumulative infiltration as a function of time measured by the autodisc. The autodisc was used to measure the variability of these soil hydraulic properties in three different sample sets: (a) a reference soil consisting of a nonrepellent, uniform, fine sand; (b) soils with the same soil textural classification derived from the same bedrock geology but having different initial burn severities; and (c) soils from different bedrock geology but having the same burn severity. The autodisc infiltrometer had greater sampling rates and volume resolution when compared with the visual minidisc infiltrometer from previous studies. There was no statistical difference in the mean values measured using the autodisc and visual minidisc, but the variability of the autodisc measurements was significantly less than the visual minidisc for a given set of samples. The greatest variability of soil hydraulic properties in reference samples with uniform particle size was attributed to different pore geometries (coefficient of variation [COV] = 0.28–0.34). Unburned field samples (same soil type) with heterogeneous particle sizes had greater variability (COV = 0.57–0.78) than the reference samples. However, this basic variability decreased or remained constant in these field samples as burn severity increased. Additional sources of variability (COV = 0.53–1.99) were attributed to multiple layers resulting from ash or sediment deposition. Results indicate that resolving differences in soil hydraulic properties from different sites requires more than the common 10 random samples because of the multiple sources of variability.

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“…Under the same soil conditions, with soil bulk density increasing, soil porosity decreases, resulting in a decrease in soil infiltration capacity [13][14][15]. In addition, soil initial water content determines the soil water potential during the initial water infiltration stage, thereby significantly affecting the process of soil infiltration [16,17]. The length and diameter of the emitter are the most important design parameters for line source irrigation, because its size determines the seepage area of the line source, which has a great influence on infiltration [18].…”

Section: Introductionmentioning

confidence: 99%

A Simplified Infiltration Model for Predicting Cumulative Infiltration during Vertical Line Source Irrigation

Fan

Huang

Gong

et al. 2018

Water

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Vertical line source irrigation is a water-saving irrigation method for enhancing direct water and nutrient delivery to the root zone, reducing soil evaporation and improving water and nutrient use efficiency. To identify its influencing factors, we performed computer simulations using the HYDRUS-2D software. The results indicate that for a given soil, the line source seepage area, but not the initial soil water content and buried depth, has a significant effect on the cumulative infiltration. We thus proposed a simplified method, taking into account the seepage area for predicting the cumulative infiltration based on the Philip model. Finally, we evaluated the accuracy of the simplified method using experimental data and found the cumulative infiltrations predicted by the simplified method were in very good agreement with the observed values, showing a low mean average error of 0.028-0.480 L, a root mean square error of 0.043-0.908 L, a percentage bias of 0.321-0.900 and a large Nash-Sutcliffe coefficient close to 1.0 (NSE ≥ 0.995). The results indicate that this simplified infiltration model, for which the only emitter parameter required is the seepage area, could provide a valuable and practical tool for irrigation design.

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Modeling effect of initial soil moisture on sorptivity and infiltration

Cited by 52 publications

References 35 publications

An improved method for determining Brooks–Corey model parameters from horizontal absorption

An improved method for determining Brooks–Corey model parameters from horizontal absorption

Sources of inherent infiltration variability in postwildfire soils

A Simplified Infiltration Model for Predicting Cumulative Infiltration during Vertical Line Source Irrigation

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